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https://slideplayer.com/slide/5853394/ | # Radian and Degree Measure Objectives: Describe Angles Use Radian and Degree measures.
## Presentation on theme: "Radian and Degree Measure Objectives: Describe Angles Use Radian and Degree measures."— Presentation transcript:
Radian and Degree Measure Objectives: Describe Angles Use Radian and Degree measures
An angle is determined by rotating a ray about its endpoint. The starting position of the ray is the initial side of the angle and the position after rotation is the terminal side. The endpoint of the ray is the vertex of the angle. This perception of an angle fits a coordinate system in which the origin is the vertex and the initial side coincides with the positive x-axis. Such an angle is in standard position. Counterclockwise rotation generates positive angles and clockwise rotation generates negative angles. Angle that have the same initial and terminal sides are called coterminal angles. Trigonometry: the measurement of triangles the relationships among the sides and angles of triangles
Radian: the measure of a central angle that intercepts an arc equal in length to the radius of the circle. Algebraically, this means that where is measured in radians. (Note that ) Degree: a measure of one degree is equivalent to a rotation of of a complete revolution about the vertex. Measure of an angle: the amount of rotation from the initial side to the terminal side.
Conversions between Degrees and Radians To convert degrees to radians, multiply degrees by EX: Convert from degrees to radians a) b) To convert radians to degrees, multiply radians by EX: Convert from radians to degrees a) b)
Fractional parts of degrees are expressed in minutes and seconds, using the prime and double prime notations, respectively. Many calculators have special keys for converting an angle in degrees, minutes, and seconds to decimal degree form, and vice versa. Decimal degrees are used to denote fractional parts of degrees
A) Determine the quadrant in which the angle lies B) Convert to degrees C) Determine two coterminal angles (one positive and one negative) for each angle. D) Determine the complement and the supplement of each angle (IF POSSIBLE). 1. EXAMPLE
A) Determine the quadrant in which the angle lies B) Convert to radians C) Determine two coterminal angles (one positive and one negative) for each angle. D) Determine the complement and the supplement of each angle (IF POSSIBLE). 2. EXAMPLE
A) Determine the quadrant in which the angle lies B) Convert to degrees C) Determine two coterminal angles (one positive and one negative) for each angle. 3. EXAMPLE
A) Determine the quadrant in which the angle lies B) Convert to radians C) Determine two coterminal angles (one positive and one negative) for each angle. 4. EXAMPLE
a) b) c) EX 5: Convert to Decimal Degrees. Round to the nearest thousandth of a degree.
a) b) c) EX 6: Convert to Degree, Minutes and Seconds | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9192929267883301, "perplexity": 1197.4392654302223}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-51/segments/1575540481281.1/warc/CC-MAIN-20191205164243-20191205192243-00522.warc.gz"} |
https://worldwidescience.org/topicpages/c/classification+systems+adl.html | #### Sample records for classification systems adl
1. Architecture Level Dependency Analysis of SOA Based System through ?-Adl
OpenAIRE
Pawan Kumar; Ratneshwer
2016-01-01
A formal Architecture Description Language (ADL) provides an effective way to dependency analysis at early stage of development. ?-ADL is an ADL that represents the static and dynamic features of software services. In this paper, we describe an approach of dependency analysis of SOA (Service Oriented Architecture) based system, at architecture level, through ?-ADL. A set of algorithms are also proposed for identification of dependency relationships from a SOA based system. The proposed algori...
2. Possibility of Independence in ADL (Activities of Daily Living) for Patients with Cervical Spinal Cord Injuries : An Evaluation based on the Zancolli Classification of Residual Arm Functions
OpenAIRE
Yoshimura, Osamu; Takayanagi, Kiyomi; Kobayashi, Ryuji; Hosoda, Masataka; Minematsu, Akira; Sasaki, Hisato; Maejima, Hiroshi; Matsuda, Yuiti; Tanaka, Satiko; Matsuo, Akihisa; Kanemura, Naohiko
1998-01-01
For patients with cervical spinal cord injuries to become independent in their ADL (Activities of Daily Living), residual arm function is very important. Also, age, sex, physical strength, obesity, spasticity, pain, contracture and motivation are related. We investigated the possibility of independence in ADL for patients with cervical spinal cord injuries, carrying out our evaluation based on the Zancolli Classification of Residual Arm Functions. Zancolli classification C6BII is taken as the...
3. A comparative study of ADL at home and at care facilities : differences between system of elderly daycare administration
OpenAIRE
Mitsumura, Mika; Someya, Fujiko
2011-01-01
[Purpose] In elderly daycare facilities, services are provided according to independence support, which is the basic philosophy of Long-Term Care Insurance, to maintain and improve the user s activities of daily living (ADL). However, the efforts aimed at independence support and methods of service vary from facility to facility. In this study, we examined the relationship between the administrations system of the facilities and the user s independence of ADL, comparing two typ...
4. Restoring ADL function after wrist surgery in children with cerebral palsy: a novel Bilateral robot system design.
Science.gov (United States)
Holley, D; Theriault, A; Kamara, S; Anewenter, V; Hughes, D; Johnson, M J
2013-06-01
Cerebral palsy is a leading cause of disability in children and reducing its effects on arm function will improve quality of life. Our goal is to train children with CP after wrist tendon transfer surgery using a robotic therapy system consisting of two robot arms and wrist robots. The therapeutic goal is to determine if the robot training combined with surgery intervention improved functional outcomes significantly more than surgery alone. To accomplish this long-term goal we have developed a Bilateral ADL Exercise Robot, BiADLER aimed at training children with CP in reach to grasp coordination on ADLs. Specifically, the robot will provide active training using an assist-as-needed. This paper presents the design concepts. PMID:24187280
5. Ontologies vs. Classification Systems
DEFF Research Database (Denmark)
Madsen, Bodil Nistrup; Erdman Thomsen, Hanne
2009-01-01
What is an ontology compared to a classification system? Is a taxonomy a kind of classification system or a kind of ontology? These are questions that we meet when working with people from industry and public authorities, who need methods and tools for concept clarification, for developing meta...... data sets or for obtaining advanced search facilities. In this paper we will present an attempt at answering these questions. We will give a presentation of various types of ontologies and briefly introduce terminological ontologies. Furthermore we will argue that classification systems, e.g. product...... classification systems and meta data taxonomies, should be based on ontologies....
6. Neuromuscular disease classification system.
Science.gov (United States)
Sáez, Aurora; Acha, Begoña; Montero-Sánchez, Adoración; Rivas, Eloy; Escudero, Luis M; Serrano, Carmen
2013-06-01
Diagnosis of neuromuscular diseases is based on subjective visual assessment of biopsies from patients by the pathologist specialist. A system for objective analysis and classification of muscular dystrophies and neurogenic atrophies through muscle biopsy images of fluorescence microscopy is presented. The procedure starts with an accurate segmentation of the muscle fibers using mathematical morphology and a watershed transform. A feature extraction step is carried out in two parts: 24 features that pathologists take into account to diagnose the diseases and 58 structural features that the human eye cannot see, based on the assumption that the biopsy is considered as a graph, where the nodes are represented by each fiber, and two nodes are connected if two fibers are adjacent. A feature selection using sequential forward selection and sequential backward selection methods, a classification using a Fuzzy ARTMAP neural network, and a study of grading the severity are performed on these two sets of features. A database consisting of 91 images was used: 71 images for the training step and 20 as the test. A classification error of 0% was obtained. It is concluded that the addition of features undetectable by the human visual inspection improves the categorization of atrophic patterns. PMID:23804164
7. Aircraft Operations Classification System
Science.gov (United States)
Harlow, Charles; Zhu, Weihong
2001-01-01
Accurate data is important in the aviation planning process. In this project we consider systems for measuring aircraft activity at airports. This would include determining the type of aircraft such as jet, helicopter, single engine, and multiengine propeller. Some of the issues involved in deploying technologies for monitoring aircraft operations are cost, reliability, and accuracy. In addition, the system must be field portable and acceptable at airports. A comparison of technologies was conducted and it was decided that an aircraft monitoring system should be based upon acoustic technology. A multimedia relational database was established for the study. The information contained in the database consists of airport information, runway information, acoustic records, photographic records, a description of the event (takeoff, landing), aircraft type, and environmental information. We extracted features from the time signal and the frequency content of the signal. A multi-layer feed-forward neural network was chosen as the classifier. Training and testing results were obtained. We were able to obtain classification results of over 90 percent for training and testing for takeoff events.
8. Bosniak Classification system
DEFF Research Database (Denmark)
Graumann, Ole; Osther, Susanne Sloth; Karstoft, Jens;
2014-01-01
Background: The Bosniak classification is a diagnostic tool for the differentiation of cystic changes in the kidney. The process of categorizing renal cysts may be challenging, involving a series of decisions that may affect the final diagnosis and clinical outcome such as surgical management....... Purpose: To investigate the inter- and intra-observer agreement among experienced uroradiologists when categorizing complex renal cysts according to the Bosniak classification. Material and Methods: The original categories of 100 cystic renal masses were chosen as “Gold Standard” (GS), established...... to the calculated weighted κ all readers performed “very good” for both inter-observer and intra-observer variation. Most variation was seen in cysts catagorized as Bosniak II, IIF, and III. These results show that radiologists who evaluate complex renal cysts routinely may apply the Bosniak classification...
9. Bosniak classification system
DEFF Research Database (Denmark)
Graumann, Ole; Osther, Susanne Sloth; Karstoft, Jens;
2016-01-01
BACKGROUND: The Bosniak classification was originally based on computed tomographic (CT) findings. Magnetic resonance (MR) and contrast-enhanced ultrasonography (CEUS) imaging may demonstrate findings that are not depicted at CT, and there may not always be a clear correlation between the findings...... at MR and CEUS imaging and those at CT. PURPOSE: To compare diagnostic accuracy of MR, CEUS, and CT when categorizing complex renal cystic masses according to the Bosniak classification. MATERIAL AND METHODS: From February 2011 to June 2012, 46 complex renal cysts were prospectively evaluated by three...... readers. Each mass was categorized according to the Bosniak classification and CT was chosen as gold standard. Kappa was calculated for diagnostic accuracy and data was compared with pathological results. RESULTS: CT images found 27 BII, six BIIF, seven BIII, and six BIV. Forty-three cysts could...
10. Classification system: Netherlands
NARCIS (Netherlands)
Hartemink, A.E.
2006-01-01
Although people have always classified soils, it is only since the mid 19th century that soil classification emerged as an important topic within soil science. It forced soil scientists to think systematically about soils and its genesis and developed to facilitate communication between soil scienti
11. CLASSIFICATION FRAMEWORK FOR COASTAL SYSTEMS
Science.gov (United States)
U.S. Environmental Protection Agency. Classification Framework for Coastal Systems. EPA/600/R-04/061. U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, Narragansett, RI, Gulf Ecology Division, Gulf Bree...
12. Classification of Magnetic Nanoparticle Systems
DEFF Research Database (Denmark)
Bogren, Sara; Fornara, Andrea; Ludwig, Frank;
2015-01-01
This study presents classification of different magnetic single- and multi-core particle systems using their measured dynamic magnetic properties together with their nanocrystal and particle sizes. The dynamic magnetic properties are measured with AC (dynamical) susceptometry and magnetorelaxomet...
13. Classification systems for stalking behavior.
Science.gov (United States)
Racine, Christopher; Billick, Stephen
2014-01-01
Stalking is a complex behavioral phenomenon that is unique in that it necessarily involves a prolonged dyadic relationship between both a perpetrator and a victim. Since criminalization of stalking behavior in the 1990s, different conceptual typologies have attempted to classify this behavior to assess risk and aid in management decisions. The authors reviewed the current literature regarding the most recent and accepted stalking classification systems. The three predominant stalker typologies currently in use include Zona's stalker-victim types, Mullen's stalker typology, and the RECON stalker typology. Of these, the RECON classification system alone was developed in an attempt to separate stalkers into groups based on previously known risk factors for behaviorally based phenomenon such as propensity for violence. Understanding and simplifying these classification systems may enhance the potential that new research will lead to evidence-based management and treatment strategies in the stalking situation. PMID:23980606
14. Classifications of Linear Controlled Systems
OpenAIRE
Li, Jing
2008-01-01
This paper is devoted to a study of linear, differential and topological classifications for linear controlled systems governed by ordinary differential equations. The necessary and sufficient conditions for the linear and topological equivalence are given. It is also shown that the differential equivalence is the same as the linear equivalence for the linear controlled systems.
15. Oral epithelial dysplasia classification systems
DEFF Research Database (Denmark)
Warnakulasuriya, S; Reibel, J; Bouquot, J;
2008-01-01
At a workshop coordinated by the WHO Collaborating Centre for Oral Cancer and Precancer in the United Kingdom issues related to potentially malignant disorders of the oral cavity were discussed by an expert group. The consensus views of the Working Group are presented in a series of papers....... In this report, we review the oral epithelial dysplasia classification systems. The three classification schemes [oral epithelial dysplasia scoring system, squamous intraepithelial neoplasia and Ljubljana classification] were presented and the Working Group recommended epithelial dysplasia grading for routine...... use. Although most oral pathologists possibly recognize and accept the criteria for grading epithelial dysplasia, firstly based on architectural features and then of cytology, there is great variability in their interpretation of the presence, degree and significance of the individual criteria...
16. Automated Periodontal Diseases Classification System
Directory of Open Access Journals (Sweden)
Aliaa A. A. Youssif
2012-01-01
Full Text Available This paper presents an efficient and innovative system for automated classification of periodontal diseases, The strength of our technique lies in the fact that it incorporates knowledge from the patients' clinical data, along with the features automatically extracted from the Haematoxylin and Eosin (H&E stained microscopic images. Our system uses image processing techniques based on color deconvolution, morphological operations, and watershed transforms for epithelium & connective tissue segmentation, nuclear segmentation, and extraction of the microscopic immunohistochemical features for the nuclei, dilated blood vessels & collagen fibers. Also, Feedforward Backpropagation Artificial Neural Networks are used for the classification process. We report 100% classification accuracy in correctly identifying the different periodontal diseases observed in our 30 samples dataset.
17. URL Crawling & classification system
OpenAIRE
Vaagland, Emil Lindgjerdet
2012-01-01
Today, malware is often found on legitimate web sites that have been hacked. The aim of this thesis was to create a system to crawl potential malicious web sites and rate them as malicious or not. Through research into current malware trends and mechanisms to detect malware on the web, we analyzed and discussed the problem space, before we began design the system architecture. After we had implemented our suggested architecture, we ran the system through tests. These test shed some light on t...
18. Multiple Fuzzy Classification Systems
CERN Document Server
Scherer, Rafał
2012-01-01
Fuzzy classifiers are important tools in exploratory data analysis, which is a vital set of methods used in various engineering, scientific and business applications. Fuzzy classifiers use fuzzy rules and do not require assumptions common to statistical classification. Rough set theory is useful when data sets are incomplete. It defines a formal approximation of crisp sets by providing the lower and the upper approximation of the original set. Systems based on rough sets have natural ability to work on such data and incomplete vectors do not have to be preprocessed before classification. To achieve better performance than existing machine learning systems, fuzzy classifiers and rough sets can be combined in ensembles. Such ensembles consist of a finite set of learning models, usually weak learners. The present book discusses the three aforementioned fields – fuzzy systems, rough sets and ensemble techniques. As the trained ensemble should represent a single hypothesis, a lot of attention is placed o...
19. Automated Periodontal Diseases Classification System
OpenAIRE
Aliaa A. A. Youssif; Abeer Saad Gawish,; Mohammed Elsaid Moussa
2012-01-01
This paper presents an efficient and innovative system for automated classification of periodontal diseases, The strength of our technique lies in the fact that it incorporates knowledge from the patients' clinical data, along with the features automatically extracted from the Haematoxylin and Eosin (H&E) stained microscopic images. Our system uses image processing techniques based on color deconvolution, morphological operations, and watershed transforms for epithelium & connective tissue se...
20. Ineffective ADL skills in women with fibromyalgia
DEFF Research Database (Denmark)
Von Bülow, Cecilie; Amris, Kirstine; La Cour, Karen;
2016-01-01
BACKGROUND: Subgroups of women with fibromyalgia likely show different activity of daily living (ADL) skill deficits. Identifying ineffective ADL skills of significance in the 'typical' woman with fibromyalgia will promote the planning of targeted occupational therapy interventions aiming...... at improving ADL ability. OBJECTIVE: To identify frequently reported ADL skill deficits of significance in subgroups of women with fibromyalgia who have decreased ADL motor ability in combination with decreased or competent ADL process ability. METHOD: Women with fibromyalgia were evaluated with the Assessment......). CONCLUSION: It is suggested that clinicians modify the individual's tasks and environments to compensate for identified ineffective ADL skills and to use the AMPS to differentiate interventions in women with fibromyalgia....
Science.gov (United States)
Mitchell, Joan S.
1997-01-01
Discusses knowledge organization tools in the context of seven challenges facing library classification systems. Highlights include revisions to the Dewey Decimal Classification, the Windows-based CD-ROM version of Dewey, support for machine-assisted classification, multilingual use of Dewey, use of Dewey as a general knowledge organization and…
2. Classification system to describe workpieces definitions
CERN Document Server
Macconnell, W R
2013-01-01
A Classification System to Describe Workpieces provides information pertinent to the fundamental aspects and principles of coding. This book discusses the various applications of the classification system of coding.Organized into three chapters, this book begins with an overview of the requirements of a system of classification pertaining adequately and equally to design, production, and work planning. This text then examines the purpose of the classification system in production to determine the most suitable means of machining a component. Other chapters consider the optimal utilization of m
3. Autoclass: An automatic classification system
Science.gov (United States)
Stutz, John; Cheeseman, Peter; Hanson, Robin
1991-01-01
The task of inferring a set of classes and class descriptions most likely to explain a given data set can be placed on a firm theoretical foundation using Bayesian statistics. Within this framework, and using various mathematical and algorithmic approximations, the AutoClass System searches for the most probable classifications, automatically choosing the number of classes and complexity of class descriptions. A simpler version of AutoClass has been applied to many large real data sets, has discovered new independently-verified phenomena, and has been released as a robust software package. Recent extensions allow attributes to be selectively correlated within particular classes, and allow classes to inherit, or share, model parameters through a class hierarchy. The mathematical foundations of AutoClass are summarized.
4. Advancing Towards a Universal Soil Classification System
Science.gov (United States)
Owens, Phillip R.; Hempel, Jon; Micheli, Erika; McBratney, Alex
2014-05-01
Within the variability of soils across the globe, there are common soil attributes that pedologists have used to group soil within taxonomic classifications. Classification systems are necessary for the communication of information about soils. There are many national classification systems used within designated countries and two classification systems used globally, the US Soil Taxonomy and the World Reference Base. There is a great need for soil scientists to develop one common language or taxonomic system to communicate information within soil science as well as to other scientists in other disciplines. The International Union of Soil Sciences Working Group for Universal Soil Classification was officially established by an IUSS Council decision in August of 2010 at the World Congress of Soil Science in Brisbane, Australia. The charge for the Working Group includes development of common standards for methods and terminology in soil observations and investigations and the development of a universal soil classification system. The Universal Soil Classification Working Group was established and the initial meeting was held at Purdue University in West Lafayette, Indiana USA. The Working Group has evaluated the current national systems and the two international systems to identify gaps in knowledge. Currently, it was determined that gaps in knowledge exists in cold soil, hydromorphic, salt affected, anthropengic, and tropical soil groups. Additionally, several members of the Working Group have utilized taxonomic distance calculations from large databases to determine the clusters of similar taxonomic groupings utilizing the classification. Additionally, the databases are being used to make allocations into logical groups to recognize "Great Soil Groups". The great soil groups will be equivalent to great groups level from Soil Taxonomy along with similar levels in the World Reference Base, Australian Soil Classification and other defined soil classification systems
5. STUDY ON CLASSIFICATION SYSTEM FOR CHINESE COAL
Institute of Scientific and Technical Information of China (English)
陈鹏
1998-01-01
An integrated coal classification system-technical/commercial and scientific/geneticclassification in China is discussed in this paper. This system shall enable producers, sellers andpurchasers to communicate unambiguously with regard to the quality of coal complying with therequirements of the respective application. The determination of perfect coal classification systemis an important measure for rational utilization of coal resources.
6. Challenges for the present CKD classification system
NARCIS (Netherlands)
Gansevoort, Ron T.; de Jong, Paul E.
2010-01-01
Purpose of review In 2002 the Kidney Disease Outcomes Quality Initiative (K/DOQI) organization published a guideline on chronic kidney disease (CKD), which contained a classification system for CKD severity, independent of cause. This classification system was immediately widely embraced. However, s
7. Music Genre Classification Systems - A Computational Approach
OpenAIRE
Ahrendt, Peter; Hansen, Lars Kai
2006-01-01
Automatic music genre classification is the classification of a piece of music into its corresponding genre (such as jazz or rock) by a computer. It is considered to be a cornerstone of the research area Music Information Retrieval (MIR) and closely linked to the other areas in MIR. It is thought that MIR will be a key element in the processing, searching and retrieval of digital music in the near future. This dissertation is concerned with music genre classification systems and in particular...
8. Trainee Occupational Therapists Scoring the Barthel ADL.
Science.gov (United States)
Martin, Elizabeth; Nugent, Chris; Bond, Raymond; Martin, Suzanne
2015-09-01
9. Gender Classification by Fuzzy Inference System
OpenAIRE
Payman Moallem; B. Somayeh Mousavi
2013-01-01
Gender classification from face images has many applications and is thus an important research topic. This paper presents an approach to gender classification based on shape and texture information gathered to design a fuzzy decision making system. Beside face shape features, Zernik moments are applied as system inputs to improve the system output which is considered as the probability of being male face image. After parameters tuning of the proposed fuzzy decision making system, 85.05% class...
10. Classification systems for natural resource management
Science.gov (United States)
Kleckner, Richard L.
1981-01-01
Resource managers employ various types of resource classification systems in their management activities such as inventory, mapping, and data analysis. Classification is the ordering or arranging of objects into groups or sets on the basis of their relationships, and as such, provide the resource managers with a structure for organizing their needed information. In addition of conforming to certain logical principles, resource classifications should be flexible, widely applicable to a variety of environmental conditions, and useable with minimal training. The process of classification may be approached from the bottom up (aggregation) or the top down (subdivision) or a combination of both, depending on the purpose of the classification. Most resource classification systems in use today focus on a single resource and are used for a single, limited purpose. However, resource managers now must employ the concept of multiple use in their management activities. What they need is an integrated, ecologically based approach to resource classification which would fulfill multiple-use mandates. In an effort to achieve resource-data compatibility and data sharing among Federal agencies, and interagency agreement has been signed by five Federal agencies to coordinate and cooperate in the area of resource classification and inventory.
11. Land Cover - Minnesota Land Cover Classification System
Data.gov (United States)
Minnesota Department of Natural Resources — Land cover data set based on the Minnesota Land Cover Classification System (MLCCS) coding scheme. This data was produced using a combination of aerial photograph...
12. Classification
Science.gov (United States)
Clary, Renee; Wandersee, James
2013-01-01
In this article, Renee Clary and James Wandersee describe the beginnings of "Classification," which lies at the very heart of science and depends upon pattern recognition. Clary and Wandersee approach patterns by first telling the story of the "Linnaean classification system," introduced by Carl Linnacus (1707-1778), who is…
13. A statistical approach to root system classification.
Directory of Open Access Journals (Sweden)
Gernot eBodner
2013-08-01
Full Text Available Plant root systems have a key role in ecology and agronomy. In spite of fast increase in root studies, still there is no classification that allows distinguishing among distinctive characteristics within the diversity of rooting strategies. Our hypothesis is that a multivariate approach for plant functional type identification in ecology can be applied to the classification of root systems. We demonstrate that combining principal component and cluster analysis yields a meaningful classification of rooting types based on morphological traits. The classification method presented is based on a data-defined statistical procedure without a priori decision on the classifiers. Biplot inspection is used to determine key traits and to ensure stability in cluster based grouping. The classification method is exemplified with simulated root architectures and morphological field data. Simulated root architectures showed that morphological attributes with spatial distribution parameters capture most distinctive features within root system diversity. While developmental type (tap vs. shoot-borne systems is a strong, but coarse classifier, topological traits provide the most detailed differentiation among distinctive groups. Adequacy of commonly available morphologic traits for classification is supported by field data. Three rooting types emerged from measured data, distinguished by diameter/weight, density and spatial distribution respectively. Similarity of root systems within distinctive groups was the joint result of phylogenetic relation and environmental as well as human selection pressure. We concluded that the data-define classification is appropriate for integration of knowledge obtained with different root measurement methods and at various scales. Currently root morphology is the most promising basis for classification due to widely used common measurement protocols. To capture details of root diversity efforts in architectural measurement
14. Music Genre Classification Systems - A Computational Approach
DEFF Research Database (Denmark)
Ahrendt, Peter
2006-01-01
that MIR will be a key element in the processing, searching and retrieval of digital music in the near future. This dissertation is concerned with music genre classification systems and in particular systems which use the raw audio signal as input to estimate the corresponding genre. This is in contrast...... be applicable to ordinary real-world music collections. The considered music genre classification systems can basically be seen as a feature representation of the song followed by a classification system which predicts the genre. The feature representation is here split into a Short-time feature extraction part...... followed by Temporal feature integration which combines the (multivariate) time-series of short-time feature vectors into feature vectors on a larger time scale. Several different short-time features with 10-40 ms frame sizes have been examined and ranked according to their significance in music genre...
15. An evaluation of classification systems for stillbirth
Directory of Open Access Journals (Sweden)
Pattinson Robert
2009-06-01
Full Text Available Abstract Background Audit and classification of stillbirths is an essential part of clinical practice and a crucial step towards stillbirth prevention. Due to the limitations of the ICD system and lack of an international approach to an acceptable solution, numerous disparate classification systems have emerged. We assessed the performance of six contemporary systems to inform the development of an internationally accepted approach. Methods We evaluated the following systems: Amended Aberdeen, Extended Wigglesworth; PSANZ-PDC, ReCoDe, Tulip and CODAC. Nine teams from 7 countries applied the classification systems to cohorts of stillbirths from their regions using 857 stillbirth cases. The main outcome measures were: the ability to retain the important information about the death using the InfoKeep rating; the ease of use according to the Ease rating (both measures used a five-point scale with a score Results InfoKeep scores were significantly different across the classifications (p ≤ 0.01 due to low scores for Wigglesworth and Aberdeen. CODAC received the highest mean (SD score of 3.40 (0.73 followed by PSANZ-PDC, ReCoDe and Tulip [2.77 (1.00, 2.36 (1.21, 1.92 (1.24 respectively]. Wigglesworth and Aberdeen resulted in a high proportion of unexplained stillbirths and CODAC and Tulip the lowest. While Ease scores were different (p ≤ 0.01, all systems received satisfactory scores; CODAC received the highest score. Aberdeen and Wigglesworth showed poor agreement with kappas of 0.35 and 0.25 respectively. Tulip performed best with a kappa of 0.74. The remainder had good to fair agreement. Conclusion The Extended Wigglesworth and Amended Aberdeen systems cannot be recommended for classification of stillbirths. Overall, CODAC performed best with PSANZ-PDC and ReCoDe performing well. Tulip was shown to have the best agreement and a low proportion of unexplained stillbirths. The virtues of these systems need to be considered in the development of an
16. Mapping a classification system to architectural education
DEFF Research Database (Denmark)
Hermund, Anders; Klint, Lars; Rostrup, Nicolai
2015-01-01
a questionnaire survey among 88 students in graduate school. Qualitative interviews with a handful of practicing architects, to be able to cross check the relevance of the education with the profession. The examination indicates the need of a new definition, in addition to the CCS’s scale, covering the earliest......This paper examines to what extent a new classification system, Cuneco Classification System, CCS, proves useful in the education of architects, and to what degree the aim of an architectural education, rather based on an arts and crafts approach than a polytechnic approach, benefits from...... the distinct terminology of the classification system. The method used to examine the relationship between education, practice and the CCS bifurcates in a quantitative and a qualitative exploration: Quantitative comparison of the curriculum with the students’ own descriptions of their studies through...
17. Myelodysplastic syndrome: classification and prognostic systems
Directory of Open Access Journals (Sweden)
Rosangela Invernizzi
2011-12-01
Full Text Available Myelodysplastic syndromes (MDS are acquired clonal disorders of hematopoiesis, that are characterized most frequently by normocellular or hypercellular bone marrow specimens, and maturation that is morphologically and functionally dysplastic. MDS constitute a complex hematological problem: differences in disease presentation, progression and outcome have made it necessary to use classification systems to improve diagnosis, prognostication and treatment selection. On the basis of new scientific and clinical information, classification and prognostic systems have recently been updated and minimal diagnostic criteria forMDS have been proposed by expert panels. In addition, in the last few years our ability to define the prognosis of the individual patient with MDS has improved. In this paper World Health Organization (WHO classification refinements and recent prognostic scoring systems for the definition of individual risk are highlighted and current criteria are discussed. The recommendations should facilitate diagnostic and prognostic evaluations in MDS and selection of patients for new effective targeted therapies.
18. Fission--fusion systems: classification and critique
International Nuclear Information System (INIS)
A useful classification scheme for hybrid systems is described and some common features that the scheme makes apparent are pointed out. The early history of fusion-fission systems is reviewed. Some designs are described along with advantages and disadvantages of each. The extension to low and moderate Q devices is noted. (U.S.)
19. Image-based Vehicle Classification System
CERN Document Server
Ng, Jun Yee
2012-01-01
Electronic toll collection (ETC) system has been a common trend used for toll collection on toll road nowadays. The implementation of electronic toll collection allows vehicles to travel at low or full speed during the toll payment, which help to avoid the traffic delay at toll road. One of the major components of an electronic toll collection is the automatic vehicle detection and classification (AVDC) system which is important to classify the vehicle so that the toll is charged according to the vehicle classes. Vision-based vehicle classification system is one type of vehicle classification system which adopt camera as the input sensing device for the system. This type of system has advantage over the rest for it is cost efficient as low cost camera is used. The implementation of vision-based vehicle classification system requires lower initial investment cost and very suitable for the toll collection trend migration in Malaysia from single ETC system to full-scale multi-lane free flow (MLFF). This project ...
20. 42 CFR 412.620 - Patient classification system.
Science.gov (United States)
2010-10-01
... 42 Public Health 2 2010-10-01 2010-10-01 false Patient classification system. 412.620 Section 412... Inpatient Rehabilitation Hospitals and Rehabilitation Units § 412.620 Patient classification system. (a) Classification methodology. (1) A patient classification system is used to classify patients in...
1. 42 CFR 412.513 - Patient classification system.
Science.gov (United States)
2010-10-01
... 42 Public Health 2 2010-10-01 2010-10-01 false Patient classification system. 412.513 Section 412... Long-Term Care Hospitals § 412.513 Patient classification system. (a) Classification methodology. CMS... LTC-DRG classification system provides a LTC-DRG, and an appropriate weighting factor, for those...
2. Updated Classification System for Proximal Humeral Fractures
Science.gov (United States)
Guix, José M. Mora; Pedrós, Juan Sala; Serrano, Alejandro Castaño
2009-01-01
Proximal humeral fractures can restrict daily activities and, therefore, deserve efficient diagnoses that minimize complications and sequels. For good diagnosis and treatment, patient characteristics, variability in the forms of the fractures presented, and the technical difficulties in achieving fair results with surgical treatment should all be taken into account. Current classification systems for these fractures are based on anatomical and pathological principles, and not on systematic image reading. These fractures can appear in many different forms, with many characteristics that must be identified. However, many current classification systems lack good reliability, both inter-observer and intra-observer for different image types. A new approach to image reading, following a well-designed set and sequence of variables to check, is needed. We previously reported such an image reading system. In the present study, we report a classification system based on this image reading system. Here we define 21 fracture characteristics and apply them along with classical Codman approaches to classify fractures. We base this novel classification system for classifying proximal humeral fractures on a review of scientific literature and improvements to our image reading protocol. Patient status, fracture characteristics and surgeon circumstances have been important issues in developing this system. PMID:19574487
3. INFORMATION SYSTEM SECURITY THREATS CLASSIFICATIONS
OpenAIRE
Sandro Gerić; Željko Hutinski
2007-01-01
Information systems are exposed to different types of security risks. Theconsequences of information systems security (ISS) breaches can vary from e.g. damaging the data base integrity to physical "destruction" of entire information system facilities, and can result with minor disruptions in less important segments of information systems, or with significant interruptions in information systems functionality. The sources of security risks are different, and can origin from inside or outside o...
4. Classification and Importance of Intrusion Detection System
Directory of Open Access Journals (Sweden)
Rajasekaran K
2012-08-01
Full Text Available An intrusion detection system (IDS is a device or software application that monitors network or system activities for malicious activities or policy violations and produces reports to a Management Station. Some systems may attempt to stop an intrusion attempt but this is neither required nor expected of a monitoring system. Due to a growing number of intrusion events and also because the Internet and local networks have become so ubiquitous, organizations are increasingly implementing various systems that monitor IT security breaches. This includes an overview of the classification of intrusion detection systems and introduces the reader to some fundamental concepts of IDS methodology: audit trail analysis and on-the-fly processing as well as anomaly detection and signature detection approaches. This research paper discusses the primary intrusion detection techniques and the classification of intrusion Detection system.
5. CLASSIFICATION OF THE MGR EMPLACEMENT DRIFT SYSTEM
Energy Technology Data Exchange (ETDEWEB)
J.A. Ziegler
2001-02-01
The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) emplacement drift system structures, systems and components (SSCs) performed by the MGR Preclosure Safety and Systems Engineering Section. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 2000). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P7 Quality Assurance Requirements and Description (QARD) (DOE 2000).
6. Classification System for Mortgage Arrear Management
NARCIS (Netherlands)
Sun, Zhe; Wiering, Marco; Petkov, Nicolai
2014-01-01
Due to the economic recession in the recent years, more and more mortgage customers default on the payments. This brings tremendous losses to banks and forces their arrear management departments to develop more efficient processes. In this paper, we propose a classification system to predict the out
7. Common occupational classification system - revision 3
Energy Technology Data Exchange (ETDEWEB)
Stahlman, E.J.; Lewis, R.E.
1996-05-01
Workforce planning has become an increasing concern within the DOE community as the Office of Environmental Restoration and Waste Management (ER/WM or EM) seeks to consolidate and refocus its activities and the Office of Defense Programs (DP) closes production sites. Attempts to manage the growth and skills mix of the EM workforce while retaining the critical skills of the DP workforce have been difficult due to the lack of a consistent set of occupational titles and definitions across the complex. Two reasons for this difficulty may be cited. First, classification systems commonly used in industry often fail to cover in sufficient depth the unique demands of DOE`s nuclear energy and research community. Second, the government practice of contracting the operation of government facilities to the private sector has introduced numerous contractor-specific classification schemes to the DOE complex. As a result, sites/contractors report their workforce needs using unique classification systems. It becomes difficult, therefore, to roll these data up to the national level necessary to support strategic planning and analysis. The Common Occupational Classification System (COCS) is designed to overcome these workforce planning barriers. The COCS is based on earlier workforce planning activities and the input of technical, workforce planning, and human resource managers from across the DOE complex. It provides a set of mutually-exclusive occupation titles and definitions that cover the broad range of activities present in the DOE complex. The COCS is not a required record-keeping or data management guide. Neither is it intended to replace contractor/DOE-specific classification systems. Instead, the system provides a consistent, high- level, functional structure of occupations to which contractors can crosswalk (map) their job titles.
8. Classification of ERP System Services
Directory of Open Access Journals (Sweden)
Petr Sodomka
2016-07-01
Full Text Available Today the ERP business information systems are an essential tool for organization management, regardless of size and field of activity. Their successful implementation and use is conditioned predominantly by IS/ICT knowledge and managerial skills required for directing their life cycle correctly. Defining and correct setting of the service level is a key requirement and skill, usually provided by a service provider based on an implementation and service contract, or an advisory organization, in particular when presale services concerning analyses and tender documentation processing are provided. The following paper discusses the characteristics of the individual service types and the particulars of their practical use. Moreover, it presents the selected significant results of the long-term research performed by the authors in the Center for inVestigations into Information Systems.
9. Classification of the MGR Administration System
International Nuclear Information System (INIS)
The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) administration system structures, systems and components (SSCs) performed by the MGR Safety Assurance Department. This analysis also provides the basis for revision of YMP/9O-55Qy Q-List (YMP 1998). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P, ''Quality Assurance Requirements and Description'' (QARD) (DOE 1998)
10. Intelligent Computer Vision System for Automated Classification
Science.gov (United States)
Jordanov, Ivan; Georgieva, Antoniya
2010-05-01
In this paper we investigate an Intelligent Computer Vision System applied for recognition and classification of commercially available cork tiles. The system is capable of acquiring and processing gray images using several feature generation and analysis techniques. Its functionality includes image acquisition, feature extraction and preprocessing, and feature classification with neural networks (NN). We also discuss system test and validation results from the recognition and classification tasks. The system investigation also includes statistical feature processing (features number and dimensionality reduction techniques) and classifier design (NN architecture, target coding, learning complexity and performance, and training with our own metaheuristic optimization method). The NNs trained with our genetic low-discrepancy search method (GLPτS) for global optimisation demonstrated very good generalisation abilities. In our view, the reported testing success rate of up to 95% is due to several factors: combination of feature generation techniques; application of Analysis of Variance (ANOVA) and Principal Component Analysis (PCA), which appeared to be very efficient for preprocessing the data; and use of suitable NN design and learning method.
11. Intelligent Computer Vision System for Automated Classification
International Nuclear Information System (INIS)
In this paper we investigate an Intelligent Computer Vision System applied for recognition and classification of commercially available cork tiles. The system is capable of acquiring and processing gray images using several feature generation and analysis techniques. Its functionality includes image acquisition, feature extraction and preprocessing, and feature classification with neural networks (NN). We also discuss system test and validation results from the recognition and classification tasks. The system investigation also includes statistical feature processing (features number and dimensionality reduction techniques) and classifier design (NN architecture, target coding, learning complexity and performance, and training with our own metaheuristic optimization method). The NNs trained with our genetic low-discrepancy search method (GLPτS) for global optimisation demonstrated very good generalisation abilities. In our view, the reported testing success rate of up to 95% is due to several factors: combination of feature generation techniques; application of Analysis of Variance (ANOVA) and Principal Component Analysis (PCA), which appeared to be very efficient for preprocessing the data; and use of suitable NN design and learning method.
12. BIOPHARMACEUTICAL CLASSIFICATION SYSTEM AND BIOWAVER: AN OVERVIEW
OpenAIRE
Puranik Prashant K; Kasar Sagar Ashok; Gadade Deepak Dilip; Mali Prabha R
2011-01-01
The biopharmaceutical classification system (BCS) has been developed to provide a scientific approach for classifying drug compounds based on solubility as related to dose and intestinal permeability in combination with the dissolution properties of the oral immediate release dosage form. BCS is to provide a regulatory tool for replacing certain bioequivalence (BE) studies by accurate in vitro dissolution tests. This review gives three dimensionless numbers which are used in BCS are absorptio...
13. Terrorism Event Classification Using Fuzzy Inference Systems
OpenAIRE
Dat Tran; Choochart Haruechaiyasak; Phayung Meesad; Uraiwan Inyaem
2010-01-01
Terrorism has led to many problems in Thai societies, not only property damage but also civilian casualties. Predicting terrorism activities in advance can help prepare and manage risk from sabotage by these activities. This paper proposes a framework focusing on event classification in terrorism domain using fuzzy inference systems (FISs). Each FIS is a decision-making model combining fuzzy logic and approximate reasoning. It is generated in five main parts: the input interface, the fuzzific...
14. Fuzzy Soft System and Arrhythmia Classification
OpenAIRE
Pankaj Srivastava; Neeraja Sharma; Aparna, C. S.
2014-01-01
An arrhythmia is an irregularity with the speed or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm. Most arrhythmias are harmless, but some can be serious or even life threatening. The present paper deals with the classification scheme of arrhythmia commonly occurring in human beings of Southeast Asian countries. Medical knowledge used in practice has been closely studied for modelling user friendly referral system to sharpen a...
15. Regional medical campuses: a new classification system.
Science.gov (United States)
Cheifetz, Craig E; McOwen, Katherine S; Gagne, Pierre; Wong, Jennifer L
2014-08-01
There is burgeoning belief that regional medical campuses (RMCs) are a significant part of the narrative about medical education and the health care workforce in the United States and Canada. Although RMCs are not new, in the recent years of medical education enrollment expansion, they have seen their numbers increase. Class expansion explains the rapid growth of RMCs in the past 10 years, but it does not adequately describe their function. Often, RMCs have missions that differ from their main campus, especially in the areas of rural and community medicine. The absence of an easy-to-use classification system has led to a lack of current research about RMCs as evidenced by the small number of articles in the current literature. The authors describe the process of the Group on Regional Medical Campuses used to develop attributes of a campus separate from the main campus that constitute a "classification" of a campus as an RMC. The system is broken into four models-basic science, clinical, longitudinal, and combined-and is linked to Liaison Committee on Medical Education standards. It is applicable to all schools and can be applied by any medical school dean or medical education researcher. The classification system paves the way for stakeholders to agree on a denominator of RMCs and conduct future research about their impact on medical education.
16. BIOPHARMACEUTICAL CLASSIFICATION SYSTEM AND BIOWAVER: AN OVERVIEW
Directory of Open Access Journals (Sweden)
Puranik Prashant K
2011-05-01
Full Text Available The biopharmaceutical classification system (BCS has been developed to provide a scientific approach for classifying drug compounds based on solubility as related to dose and intestinal permeability in combination with the dissolution properties of the oral immediate release dosage form. BCS is to provide a regulatory tool for replacing certain bioequivalence (BE studies by accurate in vitro dissolution tests. This review gives three dimensionless numbers which are used in BCS are absorption number, dissolution number, dose number.Biowaver is an important tool for formulation development. Bioavailability (BA and BE play a central role in pharmaceutical product development, and BE studies are presently being conducted for New Drug Applications (NDAs of new compounds, in supplementary NDAs for new medical indications and product line extensions, in Abbreviated New Drug Applications (ANDAs of generic products, and in applications for scale-up and post-approval changes. The principles of the BCS classification system can be applied to NDA and ANDA approvals as well as to scale-up and post approval changes in drug manufacturing. BCS classification can therefore save pharmaceutical companies a significant amount in development time and reduce costs. The aim of the present review is to present the status of BCS and discuss its future application in pharmaceutical product development.
17. Search techniques in intelligent classification systems
CERN Document Server
Savchenko, Andrey V
2016-01-01
A unified methodology for categorizing various complex objects is presented in this book. Through probability theory, novel asymptotically minimax criteria suitable for practical applications in imaging and data analysis are examined including the special cases such as the Jensen-Shannon divergence and the probabilistic neural network. An optimal approximate nearest neighbor search algorithm, which allows faster classification of databases is featured. Rough set theory, sequential analysis and granular computing are used to improve performance of the hierarchical classifiers. Practical examples in face identification (including deep neural networks), isolated commands recognition in voice control system and classification of visemes captured by the Kinect depth camera are included. This approach creates fast and accurate search procedures by using exact probability densities of applied dissimilarity measures. This book can be used as a guide for independent study and as supplementary material for a technicall...
18. CLASSIFICATION OF THE MGR BACKFILL EMPLACEMENT SYSTEM
Energy Technology Data Exchange (ETDEWEB)
R. Garrett
1999-08-31
The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) backfill emplacement system structures, systems and components (SSCs) performed by the MGR Safety Assurance Department. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 1998). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P, ''Quality Assurance Requirements and Description'' (QARD) (DOE 1998).
19. Classification of Dynamic Vehicle Routing Systems
DEFF Research Database (Denmark)
Larsen, Allan; Madsen, Oli B.G.; Solomon, Marius M.
2007-01-01
to classify dynamic vehicle routing systems. Methods for evaluation of the performance of algorithms that solve on-line routing problems are discussed and we list some of the most important issues to include in the system objective. Finally, we provide a three-echelon classification of dynamic vehicle routing......This chapter discusses important characteristics seen within dynamic vehicle routing problems. We discuss the differences between the traditional static vehicle routing problems and its dynamic counterparts. We give an in-depth introduction to the degree of dynamism measure which can be used...
20. A system for heart sounds classification.
Directory of Open Access Journals (Sweden)
Grzegorz Redlarski
Full Text Available The future of quick and efficient disease diagnosis lays in the development of reliable non-invasive methods. As for the cardiac diseases - one of the major causes of death around the globe - a concept of an electronic stethoscope equipped with an automatic heart tone identification system appears to be the best solution. Thanks to the advancement in technology, the quality of phonocardiography signals is no longer an issue. However, appropriate algorithms for auto-diagnosis systems of heart diseases that could be capable of distinguishing most of known pathological states have not been yet developed. The main issue is non-stationary character of phonocardiography signals as well as a wide range of distinguishable pathological heart sounds. In this paper a new heart sound classification technique, which might find use in medical diagnostic systems, is presented. It is shown that by combining Linear Predictive Coding coefficients, used for future extraction, with a classifier built upon combining Support Vector Machine and Modified Cuckoo Search algorithm, an improvement in performance of the diagnostic system, in terms of accuracy, complexity and range of distinguishable heart sounds, can be made. The developed system achieved accuracy above 93% for all considered cases including simultaneous identification of twelve different heart sound classes. The respective system is compared with four different major classification methods, proving its reliability.
1. A system for heart sounds classification.
Science.gov (United States)
Redlarski, Grzegorz; Gradolewski, Dawid; Palkowski, Aleksander
2014-01-01
The future of quick and efficient disease diagnosis lays in the development of reliable non-invasive methods. As for the cardiac diseases - one of the major causes of death around the globe - a concept of an electronic stethoscope equipped with an automatic heart tone identification system appears to be the best solution. Thanks to the advancement in technology, the quality of phonocardiography signals is no longer an issue. However, appropriate algorithms for auto-diagnosis systems of heart diseases that could be capable of distinguishing most of known pathological states have not been yet developed. The main issue is non-stationary character of phonocardiography signals as well as a wide range of distinguishable pathological heart sounds. In this paper a new heart sound classification technique, which might find use in medical diagnostic systems, is presented. It is shown that by combining Linear Predictive Coding coefficients, used for future extraction, with a classifier built upon combining Support Vector Machine and Modified Cuckoo Search algorithm, an improvement in performance of the diagnostic system, in terms of accuracy, complexity and range of distinguishable heart sounds, can be made. The developed system achieved accuracy above 93% for all considered cases including simultaneous identification of twelve different heart sound classes. The respective system is compared with four different major classification methods, proving its reliability. PMID:25393113
2. Extensions to the Speech Disorders Classification System (SDCS)
Science.gov (United States)
Shriberg, Lawrence D.; Fourakis, Marios; Hall, Sheryl D.; Karlsson, Heather B.; Lohmeier, Heather L.; McSweeny, Jane L.; Potter, Nancy L.; Scheer-Cohen, Alison R.; Strand, Edythe A.; Tilkens, Christie M.; Wilson, David L.
2010-01-01
This report describes three extensions to a classification system for paediatric speech sound disorders termed the Speech Disorders Classification System (SDCS). Part I describes a classification extension to the SDCS to differentiate motor speech disorders from speech delay and to differentiate among three sub-types of motor speech disorders.…
3. A program system for efficient multispectral classification
Science.gov (United States)
Åkersten, S. I.
Pixelwise multispectral classification is an important tool for analyzing remotely sensed imagery data. The computing time for performing this analysis becomes significantly large when large, multilayer images are analyzed. In the classical implementation of the supervised multispectral classification assuming gaussian-shaped multidimensional class-clusters, the computing time is furthermore approximately proportional to the square of the number of image layers. This leads to very appreciable CPU-times when large numbers of multispectral channels are used and/or temporal classification is performed. In order to decrease computer time, a classification program system has been implemented which has the following characteristics: (1) a simple one-dimensional box classifier, (2) a multidimensional box classifier, (3) a class-pivotal "canonical" classifier utilizing full maximum likelihood and making full use of within-class and between-class statistical characteristics, (4) a hybrid classifier (2 and 3 combined), and (5) a local neighbourhood filtering algorithm producing generalized classification results. The heart of the classifier is the class-pivotal canonical classifier. This algorithm is based upon an idea of Dye suggesting the use of linear transformations making possible a simultaneous evaluation of a measure of the pixel being likely not to belong to the candidate class as well as computing its full maximum likelihood ratio. In case it is more likely to be misclassified the full maximum likelihood evaluation can be truncated almost immediately, i.e. the candidate class can often be rejected using only one or two of the available transformed spectral features. The result of this is a classifier with CPU-time which is empirically shown to be linearly dependent upon the number of image layers. The use of the hybrid classifier lowers the CPU-time with another factor of 3-4. Furthermore, for certain problems like classifying water-non water a single spectral band
4. A simplified classification system for partially edentulous spaces
OpenAIRE
Bhandari Aruna J, Bhandari Akshay J
2014-01-01
Background: There is no single universally employed classification system that will specify the exact edentulous situation. Several classification systems exist to group the situation and avoid confusion. Classifications based on edentulous areas, finished restored prostheses, type of direct retainers or fulcrum lines are there. Some are based depending on the placement of the implants. Widely accepted Kennedy Applegate classification does not give any idea about length, span or number of tee...
5. Functional classifications for cerebral palsy: correlations between the gross motor function classification system (GMFCS), the manual ability classification system (MACS) and the communication function classification system (CFCS).
Science.gov (United States)
Compagnone, Eliana; Maniglio, Jlenia; Camposeo, Serena; Vespino, Teresa; Losito, Luciana; De Rinaldis, Marta; Gennaro, Leonarda; Trabacca, Antonio
2014-11-01
This study aimed to investigate a possible correlation between the gross motor function classification system-expanded and revised (GMFCS-E&R), the manual abilities classification system (MACS) and the communication function classification system (CFCS) functional levels in children with cerebral palsy (CP) by CP subtype. It was also geared to verify whether there is a correlation between these classification systems and intellectual functioning (IF) and parental socio-economic status (SES). A total of 87 children (47 males and 40 females, age range 4-18 years, mean age 8.9±4.2) were included in the study. A strong correlation was found between the three classifications: Level V of the GMFCS-E&R corresponds to Level V of the MACS (rs=0.67, p=0.001); the same relationship was found for the CFCS and the MACS (rs=0.73, pGMFCS-E&R and the CFCS (rs=0.61, p=0.001). The correlations between the IQ and the global functional disability profile were strong or moderate (GMFCS and IQ: rs=0.66, p=0.001; MACS and IQ: rs=0.58, p=0.001; CFCS and MACS: rs=0.65, p=0.001). The Kruskal-Wallis test was used to determine if there were differences between the GMFCS-E&R, the CFCS and the MACS by CP type. CP types showed different scores for the IQ level (Chi-square=8.59, df=2, p=0.014), the GMFCS-E&R (Chi-square=36.46, df=2, pGMFCS-E&R, CFCS and MACS) complement each other to provide a better description of the functional profile of CP. The systematic evaluation of the IQ can provide useful information about a possible future outcome for every functional level. The SES does not appear to affect functional profiles.
6. Fuzzy Rule Base System for Software Classification
Directory of Open Access Journals (Sweden)
2013-07-01
Full Text Available Given the central role that software development plays in the delivery and application of informationtechnology, managers have been focusing on process improvement in the software development area. Thisimprovement has increased the demand for software measures, or metrics to manage the process. Thismetrics provide a quantitative basis for the development and validation of models during the softwaredevelopment process. In this paper a fuzzy rule-based system will be developed to classify java applicationsusing object oriented metrics. The system will contain the following features:Automated method to extract the OO metrics from the source code,Default/base set of rules that can be easily configured via XML file so companies, developers, teamleaders,etc, can modify the set of rules according to their needs,Implementation of a framework so new metrics, fuzzy sets and fuzzy rules can be added or removeddepending on the needs of the end user,General classification of the software application and fine-grained classification of the java classesbased on OO metrics, andTwo interfaces are provided for the system: GUI and command.
7. Gender classification system in uncontrolled environments
Science.gov (United States)
Zeng, Pingping; Zhang, Yu-Jin; Duan, Fei
2011-01-01
Most face analysis systems available today perform mainly on restricted databases of images in terms of size, age, illumination. In addition, it is frequently assumed that all images are frontal and unconcealed. Actually, in a non-guided real-time supervision, the face pictures taken may often be partially covered and with head rotation less or more. In this paper, a special system supposed to be used in real-time surveillance with un-calibrated camera and non-guided photography is described. It mainly consists of five parts: face detection, non-face filtering, best-angle face selection, texture normalization, and gender classification. Emphases are focused on non-face filtering and best-angle face selection parts as well as texture normalization. Best-angle faces are figured out by PCA reconstruction, which equals to an implicit face alignment and results in a huge increase of the accuracy for gender classification. Dynamic skin model and a masked PCA reconstruction algorithm are applied to filter out faces detected in error. In order to fully include facial-texture and shape-outline features, a hybrid feature that is a combination of Gabor wavelet and PHoG (pyramid histogram of gradients) was proposed to equitable inner texture and outer contour. Comparative study on the effects of different non-face filtering and texture masking methods in the context of gender classification by SVM is reported through experiments on a set of UT (a company name) face images, a large number of internet images and CAS (Chinese Academy of Sciences) face database. Some encouraging results are obtained.
8. 40 CFR 141.710 - Bin classification for filtered systems.
Science.gov (United States)
2010-07-01
... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Bin classification for filtered... Cryptosporidium Treatment Technique Requirements § 141.710 Bin classification for filtered systems. (a) Following... applicable calculation for bin classification in paragraphs (b)(1) through (4) of this section. (c)...
9. Nuclear reactors transients identification and classification system
International Nuclear Information System (INIS)
This work describes the study and test of a system capable to identify and classify transients in thermo-hydraulic systems, using a neural network technique of the self-organizing maps (SOM) type, with the objective of implanting it on the new generations of nuclear reactors. The technique developed in this work consists on the use of multiple networks to do the classification and identification of the transient states, being each network a specialist at one respective transient of the system, that compete with each other using the quantization error, that is a measure given by this type of neural network. This technique showed very promising characteristics that allow the development of new functionalities in future projects. One of these characteristics consists on the potential of each network, besides responding what transient is in course, could give additional information about that transient. (author)
10. Applications of CRACK in the Classification of Integrable Systems
OpenAIRE
Wolf, Thomas
2003-01-01
Work on different classification problems is described as: the classification of integrable vector evolution equations, NLS systems with two vector unknowns, systems with one scalar and one vector unknown, classification of integrable Hamiltonians and non-local 2+1 dimensional equations. All these problems lead to large bi-linear algebraic systems to be solved. In an extended appendix an overview of the computer algebra package is given that was used to solve these systems.
11. Terrorism Event Classification Using Fuzzy Inference Systems
CERN Document Server
Inyaem, Uraiwan; Meesad, Phayung; Tran, Dat
2010-01-01
Terrorism has led to many problems in Thai societies, not only property damage but also civilian casualties. Predicting terrorism activities in advance can help prepare and manage risk from sabotage by these activities. This paper proposes a framework focusing on event classification in terrorism domain using fuzzy inference systems (FISs). Each FIS is a decision-making model combining fuzzy logic and approximate reasoning. It is generated in five main parts: the input interface, the fuzzification interface, knowledge base unit, decision making unit and output defuzzification interface. Adaptive neuro-fuzzy inference system (ANFIS) is a FIS model adapted by combining the fuzzy logic and neural network. The ANFIS utilizes automatic identification of fuzzy logic rules and adjustment of membership function (MF). Moreover, neural network can directly learn from data set to construct fuzzy logic rules and MF implemented in various applications. FIS settings are evaluated based on two comparisons. The first evaluat...
12. A Curriculum-Based Classification System for Community Colleges.
Science.gov (United States)
Schuyler, Gwyer
2003-01-01
Proposes and tests a community college classification system based on curricular characteristics and their association with institutional characteristics. Seeks readily available data correlates to represent percentage of a college's course offerings that are in the liberal arts. A simple two-category classification system using total enrollment…
13. Designing a Classification System for Internet Offenders: Doing Cognitive Distortions
Science.gov (United States)
Hundersmarck, Steven F.; Durkin, Keith F.; Delong, Ronald L.
2007-01-01
Televised features such as NBC's "To Catch a Predator" have highlighted the growing problem posed by Internet sexual predators. This paper reports on the authors' attempts in designing a classification system for Internet offenders. The classification system was designed based on existing theory, understanding the nature of Internet offenders and…
14. Classification process in a text document recommender system
Directory of Open Access Journals (Sweden)
Dan MUNTEANU
2005-12-01
Full Text Available This paper presents the classification process in a recommender system used for textual documents taken especially from web. The system uses in the classification process a combination of content filters, event filters and collaborative filters and it uses implicit and explicit feedback for evaluating documents.
Science.gov (United States)
Matolak, David W.
2003-01-01
16. A novel classification system for aging theories
Directory of Open Access Journals (Sweden)
2013-03-01
Full Text Available Theories of lifespan evolution are a source of confusion amongst aging researchers. After a century of aging research the dispute over whether the aging process is active or passive persists and a comprehensive and universally accepted theoretical model remains elusive. Evolutionary aging theories primarily dispute whether the aging process is exclusively adapted to favor the kin or exclusively non-adapted to favor the individual. Interestingly, contradictory data and theories supporting both exclusively programmed and exclusively non-programmed theories continue to grow. However, this is a false dichotomy; natural selection favors traits resulting in efficient reproduction whether they benefit the individual or the kin. Thus, to understand the evolution of aging, first we must understand the environment-dependent balance between the advantages and disadvantages of extended lifespan in the process of spreading genes. As described by distinct theories, different niches and environmental conditions confer on extended lifespan a range of fitness values varying from highly beneficial to highly detrimental. Here, we considered the range of fitness values for extended lifespan and develop a fitness-based framework for categorizing existing theories. We show that all theories can be classified into four basic types: secondary (beneficial, maladaptive (neutral, assisted death (detrimental and senemorphic aging (varying between beneficial to detrimental. We anticipate that this classification system will assist with understanding and interpreting aging/death by providing a way of considering theories as members of one of these classes rather than consideration of their individual details.
17. Examining Literary Warrant in Ancient Chinese Book Classification Systems
Directory of Open Access Journals (Sweden)
Hui-Chen Cheng
2016-06-01
Full Text Available This study examines the application of literary warrant—a key principle in modern classification theory—in traditional Chinese bibliographic classifications for the purpose of improving the understanding of classification theory in the Chinese tradition. The concept of literary warrant is first briefly discussed. Next, the author analyzes a number of selected book classification systems from premodern China to determine whether literary warrant is a factor in their design and how it is applied. This paper concludes with a summary of the findings. [Article content in Chinese
18. 78 FR 58153 - Prevailing Rate Systems; North American Industry Classification System Based Federal Wage System...
Science.gov (United States)
2013-09-23
... RIN 3206-AM78 Prevailing Rate Systems; North American Industry Classification System Based Federal... Industry Classification System (NAICS) codes currently used in Federal Wage System wage survey industry..., 2013, the U.S. Office of Personnel Management (OPM) issued a proposed rule (78 FR 18252) to update...
19. Towards a Collaborative Intelligent Tutoring System Classification Scheme
Science.gov (United States)
Harsley, Rachel
2014-01-01
This paper presents a novel classification scheme for Collaborative Intelligent Tutoring Systems (CITS), an emergent research field. The three emergent classifications of CITS are unstructured, semi-structured, and fully structured. While all three types of CITS offer opportunities to improve student learning gains, the full extent to which these…
20. EPUAP classification system for pressure ulcers: European reliability study.
NARCIS (Netherlands)
Beeckman, D.; Schoonhoven, L.; Fletcher, J.; Furtado, K.; Gunningberg, L.; Heyman, H.; Lindholm, C.; Paquay, L.; Verdu, J.; Defloor, T.
2007-01-01
AIM: This paper is a report of a study of the inter-observer reliability of the European Pressure Ulcer Advisory Panel pressure ulcer classification system and of the differential diagnosis between moisture lesions and pressure ulcers. BACKGROUND: Pressure ulcer classification is a valuable tool to
1. Calibration of a Plastic Classification System with the Ccw Model
International Nuclear Information System (INIS)
This document describes the calibration of a plastic Classification system with the Ccw model (Classification by Quantum's built with Wavelet Coefficients). The method is applied to spectra of plastics usually present in domestic wastes. Obtained results are showed. (Author) 16 refs
2. New C2 synchondrosal fracture classification system
Energy Technology Data Exchange (ETDEWEB)
Rusin, Jerome A.; Ruess, Lynne [Department of Radiology, Nationwide Children' s Hospital, Columbus, OH (United States); The Ohio State University College of Medicine and Public Health, Columbus, OH (United States); Daulton, Robert S. [Department of Radiology, Nationwide Children' s Hospital, Columbus, OH (United States)
2015-06-15
Excessive cervical flexion-extension accompanying mild to severe impact injuries can lead to C2 synchondrosal fractures in young children. To characterize and classify C2 synchondrosal fracture patterns. We retrospectively reviewed imaging and medical records of children who were treated for cervical spine fractures at our institution between 1995 and 2014. We reviewed all fractures involving the five central C2 synchondroses with regard to patient demographics, mechanism of injury, fracture pattern, associated fractures and other injuries, treatment plans and outcome. Fourteen children had fractures involving the central C2 synchondroses. There were nine boys and five girls, all younger than 6 years. We found four distinct fracture patterns. Eleven complete fractures were further divided into four subtypes (a, b, c and d) based on degree of anterior displacement of the odontoid segment and presence of distraction. Nine of these 11 children had fractures through both odontoneural synchondroses and the odontocentral synchondrosis; one had fractures involving both neurocentral synchondroses and the odontoneural synchondrosis; one had fractures through bilateral odontoneural and bilateral neurocentral synchondroses. Three children had incomplete fractures, defined as a fracture through a single odontoneural synchondrosis with or without partial extension into either the odontocentral or the adjacent neurocentral synchondroses. All complete fractures were displaced or angulated. Four had associated spinal cord injury, including two contusions (subtype c fractures) and two fatal transections (subtype d fractures). Most children were treated with primary halo stabilization. Subtype c fractures required surgical fixation. We describe four patterns of central C2 synchondrosal fractures, including two unique patterns that have not been reported. We propose a classification system to distinguish these fractures and aid in treatment planning. (orig.)
3. EAI-oriented information classification code system in manufacturing enterprises
Institute of Scientific and Technical Information of China (English)
Junbiao WANG; Hu DENG; Jianjun JIANG; Binghong YANG; Bailing WANG
2008-01-01
Although the traditional information classifi-cation coding system in manufacturing enterprises (MEs) emphasizes the construction of code standards, it lacks the management of the code creation, code data transmission and so on. According to the demands of enterprise application integration (EAI) in manufacturing enter-prises, an enterprise application integration oriented information classification code system (EAIO-ICCS) is proposed. EAIO-ICCS expands the connotation of the information classification code system and assures the identity of the codes in manufacturing enterprises with unified management of codes at the view of its lifecycle.
4. The theory and practice of the Dewey Decimal Classification system
CERN Document Server
Satija, M P
2013-01-01
The Dewey Decimal Classification system (DDC) is the world's most popular library classification system. The 23rd edition of the DDC was published in 2011. This second edition of The Theory and Practice of the Dewey Decimal Classification System examines the history, management and technical aspects of the DDC up to its latest edition. The book places emphasis on explaining the structure and number building techniques in the DDC and reviews all aspects of subject analysis and number building by the most recent version of the DDC. A history of, and introduction to, the DDC is followed by subjec
5. Economic systems: scientific cognition methodology and classification criteria
OpenAIRE
Dmytrychenko, Liana
2016-01-01
The paper explores methodological approaches to determination of the essence and criteria of economic system classification. Among diversified approaches to classification of economic systems two major ones are identified, namely formational and civilizational. Researchers' views of the relation between these approaches are reviewed.It is reasoned that out of the two methodological approaches to periodization of economic systems the formational one is the most correct technique from the scien...
6. A proposed ecosystem services classification system to support green accounting
Science.gov (United States)
There are a multitude of actual or envisioned, complete or incomplete, ecosystem service classification systems being proposed to support Green Accounting. Green Accounting is generally thought to be the formal accounting attempt to factor environmental production into National ...
7. Symplectic Topology of Integrable Hamiltonian Systems, II: Topological Classification
OpenAIRE
Zung, Nguyen Tien
2000-01-01
The main purpose of this paper is to give a topological and symplectic classification of completely integrable Hamiltonian systems in terms of characteristic classes and other local and global invariants.
8. Towards a classification of natural bi-hamiltonian systems
OpenAIRE
Tsiganov, A. V.
2006-01-01
For construction and classification of the natural integrable systems we propose to use a criterion of separability in Darboux--Nijenhuis coordinates, which can be tested without an a priori explicit knowledge of these coordinates.
9. Classification systems and selection systems: the risks of radical innovation and category spanning
NARCIS (Netherlands)
N.M. Wijnberg
2011-01-01
This paper looks at the relations between classification and competition, using the theoretical framework of selection system theory. In a particular competitive arena more than one classification system can be in use. The proportion of classification systems in use by consumers that are also in use
10. A simplified classification system for partially edentulous spaces
Directory of Open Access Journals (Sweden)
Bhandari Aruna J, Bhandari Akshay J
2014-04-01
Full Text Available Background: There is no single universally employed classification system that will specify the exact edentulous situation. Several classification systems exist to group the situation and avoid confusion. Classifications based on edentulous areas, finished restored prostheses, type of direct retainers or fulcrum lines are there. Some are based depending on the placement of the implants. Widely accepted Kennedy Applegate classification does not give any idea about length, span or number of teeth missing. Rule 6 governing the application of Kennedy method states that additional edentulous areas are referred as modification number 1,2 etc. Rule 7 states that extent of the modification is not considered; only the number of edentulous areas is considered. Hence there is a need to modify the Kennedy –Applegate System. Aims: This new classification system is an attempt to modify Kennedy –Applegate System so as to give the exact idea about missing teeth, space, span, side and areas of partially edentulous arches. Methods and Material: This system will provide the information regarding Maxillary or Mandibular partially edentulous arches, Left or Right side, length of the edentulous space, number of teeth missing and whether there will be tooth borne or tooth – tissue borne prosthesis. Conclusions: This classification is easy for application, communication and will also help to design the removable cast partial denture in a better logical and systematic way. Also, this system will give the idea of the edentulous status and the number of missing teeth in fixed, hybrid or implant prosthesis.
11. A Classification System for Peri-implant Diseases and Conditions.
Science.gov (United States)
Sarmiento, Hector L; Norton, Michael R; Fiorellini, Joseph P
2016-01-01
Peri-implant bone levels are influenced by pathologic and nonpathologic conditions. The understanding of peri-implant disease has evolved over the past several decades, and the classification of peri-implantitis has been limited to descriptions of disease progression or those involving soft and/or hard tissues (peri-implant mucositis or peri-implantitis). However, no classification system has been established based on etiology. The objective of this study was to identify various etiologies for peri-implantitis and to establish a classification system based on the pathogenesis. The results indicate that the majority of bone loss was related to biofilm, followed by iatrogenic factors, exogenous irritants, absence of keratinized tissue, and extrinsic pathology. The proposed classification system will allow the clinician to properly diagnose peri-implant diseases in relation to etiology. These conditions may respond differently to applied therapies. PMID:27560674
12. Sensitivity of different ADL measures to apraxia and motor impairments
NARCIS (Netherlands)
Donkervoort, M; Dekker, J; Deelman, BG
2002-01-01
Objective: To determine whether specifically designed activities of daily living (ADL) observations can measure disability due to apraxia with more sensitivity than the Barthel ADL Index, a conventional functional scale. Design: Cross-sectional study. Setting: Rehabilitation centres and nursing home
13. The 2010 Standard Occupational Classification (SOC): A Classification System Gets an Update
Science.gov (United States)
Emmel, Alissa; Cosca, Theresa
2010-01-01
Making sense of occupational data isn't always easy. But the task is less daunting when the data are well organized. For Federal occupational statistics, the Standard Occupational Classification (SOC) system establishes that organization. And a recent revision to the SOC means that the data will be current, in addition to being well organized. The…
14. On deformation and classification of V-systems
OpenAIRE
V. Schreiber; A.P. Veselov
2014-01-01
The V-systems are special finite sets of covectors which appeared in the theory of the generalized Witten-Dijkgraaf-Verlinde-Verlinde (WDVV) equations. Several families of V-systems are known but their classification is an open problem. We derive the relations describing the infinitesimal deformations of V-systems and use them to study the classification problem for V-systems in dimension 3. We discuss also possible matroidal structures of V-systems in relation with projective geometry and gi...
15. Comparison of the clinical applicability of Miller's classification system to Kumar and Masamatti's classification system of gingival recession
Science.gov (United States)
Kumar, Ashish; Gupta, Geeti; Puri, Komal; Bansal, Mansi; Jain, Deept; Khatri, Manish; Masamatti, Sujata Surendra
2015-01-01
Background: The aims of the present study were to (i) Find the percentage of recession cases that could be classified by application of Miller's and/or Kumar and Masamatti's classification of gingival recession, and (ii) compare the percentage of clinical applicability of Miller's criteria and Kumar and Masamatti's criteria to the total recessions present. Materials and Methods: A total of 104 patients (1089 recession cases) were included in the study wherein they were classified using both Miller's and Kumar and Masamatti's classification systems of gingival recession. Percentage comparison of the application of both classification systems was done. Results: Data analysis showed that though all the cases of the recession were classified by Kumar and Masamatti's classification, only 34.61% cases were classified by Miller's classification. 19.10% cases were completely (having only labial/buccal recession) classified. In 15.51% (out of 34.61%) cases, only buccal recession was classified according to Miller's criteria and included in this category, although these cases had both buccal and lingual/palatal recessions. Furthermore, 29.75% cases of recession with interdental loss and marginal tissue loss coronal to mucogingival junction (MGJ) remained uncategorized by Miller's classification; categorization of palatal/lingual recession was possible with Kumar and Masamatti's classification. Conclusion: The elaborative evaluation of both buccal and palatal/lingual recession by the Kumar and Masamatti's classification system can be used to overcome the limitations of Miller's classification system, especially the cases with interdental loss and having marginal tissue loss coronal to MGJ. PMID:26644724
16. Medical classification systems in Canada: moving toward the year 2000
OpenAIRE
Lalonde, A N; Taylor, E.
1997-01-01
The use of different standards for coding diagnoses and procedures has been identified as a major obstacle to the collection and analysis of data across the various jurisdictions in Canada. In this article the authors briefly describe the current and future situation of medical classification systems in Canada and discuss some of the potential benefits and implications of adopting the 10th revision of the International Statistical Classification of Diseases and Related Health Problems and a r...
17. Classification of solvable 3-dimensional Lie triple systems
OpenAIRE
Bouetou, Thomas Bouetou
2003-01-01
We give the classification of solvable and splitting Lie triple system and it turn that, up to isomorphism there exist 7 non isomorphic canonical Lie triple systems and 6 non isomorphic splitting canonical Lie triple systems and find the solvable Lie algebras associated.
18. Development of the Gross Motor Function Classification System (1997)
Science.gov (United States)
Morris, Christopher
2008-01-01
To address the need for a standardized system to classify the gross motor function of children with cerebral palsy, the authors developed a five-level classification system analogous to the staging and grading systems used in medicine. Nominal group process and Delphi survey consensus methods were used to examine content validity and revise the…
19. Comparing the performance of different stream classification systems using aquatic macroinvertebrates
OpenAIRE
Márlon de Castro Vasconcelos; Adriano Sanches Melo; Albano Schwarzbold
2013-01-01
AIM: We evaluated five stream classification systems observing: 1) differences in richness, abundance and macroinvertebrates communities among stream classes within classification systems; and 2) whether classification systems present better performance using macroinvertebrates. Additionally, we evaluated the effects of taxonomic resolution and data type (abundance and presence) on results. METHODS: Five stream classification systems were used, two based on hydroregions, one based on ecoregio...
20. CLASSIFICATION OF THE MGR WASTE EMPLACEMENT/RETRIEVAL SYSTEM
Energy Technology Data Exchange (ETDEWEB)
J.A. Ziegler
2000-11-08
The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) waste emplacement/retrieved system structures, systems and components (SSCs) performed by the MGR Preclosure Safety and Systems Engineering Section. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 2000). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P, Quality Assurance Requirements and Description (QARD) (DOE 2000). This QA classification incorporates the current MGR design and the results of the ''Design Basis Event Frequency and Dose Calculation for Site Recommendation'' (CRWMS M&O 2000a). The content and technical approach of this analysis is in accordance with the development plan ''QA Classification of MGR Structures, Systems, and Components'' (CRWMS M&O 1999b).
1. Systematic Review and Classification on Video Surveillance Systems
Directory of Open Access Journals (Sweden)
Fereshteh Falah Chamasemani
2013-06-01
Full Text Available Recently, various conferences and journals have published articles related to Video Surveillance Systems, indicating researchers’ attention. The goal of this review is to examine the latest works were published in journals, propose a new classification framework of video surveillance systems and investigate each aspect of this classification framework. This paper provides a comprehensive and systematic literature review of video surveillance systems from 2010-2011, extracted from six online digital libraries using article’s title and keyword. The proposed classification framework is expanded on the basis of architecture of video surveillance systems, which is composed of six layers: Concept and Foundation Layer, Network Infrastructure Layer, Processing Layer, Communication Layer, Application Layer, and User Interaction Layer. This review shows, although many publication and research focus on real-time aspect of the challenge, only few researches have investigated the deployment of extracted and retrieved information for forensic video surveillance.
2. Optimizing Mining Association Rules for Artificial Immune System based Classification
Directory of Open Access Journals (Sweden)
SAMEER DIXIT
2011-08-01
Full Text Available The primary function of a biological immune system is to protect the body from foreign molecules known as antigens. It has great pattern recognition capability that may be used to distinguish between foreigncells entering the body (non-self or antigen and the body cells (self. Immune systems have many characteristics such as uniqueness, autonomous, recognition of foreigners, distributed detection, and noise tolerance . Inspired by biological immune systems, Artificial Immune Systems have emerged during the last decade. They are incited by many researchers to design and build immune-based models for a variety of application domains. Artificial immune systems can be defined as a computational paradigm that is inspired by theoretical immunology, observed immune functions, principles and mechanisms. Association rule mining is one of the most important and well researched techniques of data mining. The goal of association rules is to extract interesting correlations, frequent patterns, associations or casual structures among sets of items in thetransaction databases or other data repositories. Association rules are widely used in various areas such as inventory control, telecommunication networks, intelligent decision making, market analysis and risk management etc. Apriori is the most widely used algorithm for mining the association rules. Other popular association rule mining algorithms are frequent pattern (FP growth, Eclat, dynamic itemset counting (DIC etc. Associative classification uses association rule mining in the rule discovery process to predict the class labels of the data. This technique has shown great promise over many other classification techniques. Associative classification also integrates the process of rule discovery and classification to build the classifier for the purpose of prediction. The main problem with the associative classification approach is the discovery of highquality association rules in a very large space of
3. Classification system for reporting events involving human malfunctions
International Nuclear Information System (INIS)
The report describes a set of categories for reporting industrial incidents and events involving human malfunction. The classification system aims at ensuring information adequate for improvement of human work situations and man-machine interface systems and for attempts to quantify ''human error'' rates. The classification system has a multifacetted non-hierarchial structure and its compatibility with Ispra's ERDS classification is described. The collection of the information in general and for quantification purposes are discussed. 24 categories, 12 of which being human factors oriented, are listed with their respective subcategories, and comments are given. Underlying models of human data processes and their typical malfunctions and of a human decision sequence are described. (author)
4. CLASSIFICATION OF THE MGR WASTE HANDLING BUILDING VENTILATION SYSTEM
Energy Technology Data Exchange (ETDEWEB)
J.A. Ziegler
2000-11-02
The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) waste handling building ventilation system structures, systems and components (SSCs) performed by the MGR Preclosure Safety and Systems Engineering Section. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 2000). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P, ''Quality Assurance Requirements and Description'' (QARD) (DOE 2000). This QA classification incorporates the current MGR design and the results of the ''Design Basis Event Frequency and Dose Calculation for Site Recommendation'' (CRWMS M&O 2000a) and ''Bounding Individual Category 1 Design Basis Event Dose Calculation to Support Quality Assurance Classification'' (Gwyn 2000).
5. Classification system for reporting events involving human malfunctions
International Nuclear Information System (INIS)
The report describes a set of categories for reporting industrial incidents and events involving human malfunction. The classification system aims at ensuring information adequate for improvement of human work situations and man-machine interface systems and for attempts to quantify ''human error'' rates. The classification system has a multifacetted non-hierarchical structure and its compatibility with Ispra's ERDS classification is described. The collection of the information in general and for quantification purposes are discussed. 24 categories, 12 of which being human factors-oriented, are listed with their respective subcategories, and comments are given. Underlying models of human data process and their typical malfuntions and of a human decision sequence are described. The work reported is a joint contribution to the CSNI Group of Experts on Human Error Data and Assessment
6. What's behind the Biological Classification System in Use Today?
Science.gov (United States)
Robertson, William C.
2010-01-01
Whether students should memorize classification schemes (taxonomies) is a column in itself, but the author can address the role that this system plays in the study of biology. To that end, it will help to address how the system developed over time. And toward "that" end, you will do a simple activity to start. (Contains 3 figures.)
7. Advances in metals classification under the United Nations globally harmonized system of classification and labeling.
Science.gov (United States)
Skeaff, James; Adams, William J; Rodriguez, Patricio; Brouwers, Tony; Waeterschoot, Hugo
2011-10-01
This article shows how regulatory obligations mandated for metal substances can be met with a laboratory-based transformation/dissolution (T/D) method for deriving relevant hazard classification outcomes, which can then be linked to attendant environmental protection management decisions. We report the results of a ring-test at 3 laboratories conducted to determine the interlaboratory precision of the United Nations T/D Protocol (T/DP) in generating data for classifying 4 metal-bearing substances for acute and chronic toxicity under the United Nations Globally Harmonized System of Classification and Labelling (GHS) criteria with respect to the aquatic environment. The test substances were Ni metal powder, cuprous oxide (Cu(2) O) powder, tricobalt tetroxide (Co(3) O(4) ) powder, and cuttings of a NILO K Ni-Co-Fe alloy. Following GHS Annex 10 guidelines, we tested 3 loadings (1, 10, and 100 mg/L) of each substance at pH 6 and 8 for 7 or 28 d to yield T/D data for acute and chronic classification, respectively. We compared the T/DP results (dissolved metal in aqueous media) against acute and chronic ecotoxicity reference values (ERVs) for each substance to assess GHS classification outcomes. For dissolved metal ions, the respective acute and chronic ERVs established at the time of the T/D testing were: 29 and 8 µg/L for Cu; 185 and 1.5 µg/L for Co; and 13.3 and 1.0 mg/L for Fe. The acute ERVs for Ni were pH-dependent: 120 and 68 µg/L at pH 6 and 8, respectively, whereas the chronic ERV for Ni was 2.4 µg/L. The acute classification outcomes were consistent among 3 laboratories: cuprous oxide, Acute 1; Ni metal powder, Acute 3; Co(3) O(4) and the NILO K alloy, no classification. We obtained similar consistent results in chronic classifications: Cu(2) O, Ni metal powder, and Co(3) O(4) , Chronic 4; and the NILO K alloy, no classification. However, we observed equivocal results only in 2 of a possible 48 cases where the coefficient of variation of final T
8. Binary classification of real sequences by discrete-time systems
Science.gov (United States)
Kaliski, M. E.; Johnson, T. L.
1979-01-01
This paper considers a novel approach to coding or classifying sequences of real numbers through the use of (generally nonlinear) finite-dimensional discrete-time systems. This approach involves a finite-dimensional discrete-time system (which we call a real acceptor) in cascade with a threshold type device (which we call a discriminator). The proposed classification scheme and the exact nature of the classification problem are described, along with two examples illustrating its applicability. Suggested approaches for further research are given.
9. Intelligent Decision Support System for Bank Loans Risk Classification
Institute of Scientific and Technical Information of China (English)
杨保安; 马云飞; 俞莲
2001-01-01
Intelligent Decision Support System (IISS) for Bank Loans Risk Classification (BLRC), based on the way of integration Artificial Neural Network (ANN) and Expert System (ES), is proposed. According to the feature of BLRC, the key financial and non-financial factors are analyzed. Meanwhile, ES and Model Base (MB) which contain ANN are designed . The general framework,interaction and integration of the system are given. In addition, how the system realizes BLRC is elucidated in detail.
10. Classifications of central solar domestic hot water systems
Science.gov (United States)
Guo, J. Y.; Hao, B.; Peng, C.; Wang, S. S.
2016-08-01
Currently, there are many means by which to classify solar domestic hot water systems, which are often categorized according to their scope of supply, solar collector positions, and type of heat storage tank. However, the lack of systematic and scientific classification as well as the general disregard of the thermal performance of the auxiliary heat source is important to DHW systems. Thus, the primary focus of this paper is to determine a classification system for solar domestic hot water systems based on the positions of the solar collector and auxiliary heating device, both respectively and in combination. Field-testing data regarding many central solar DHW systems demonstrates that the position of the auxiliary heat source clearly reflects the operational energy consumption. The consumption of collective auxiliary heating hot water system is much higher than individual auxiliary heating hot water system. In addition, costs are significantly reduced by the separation of the heat storage tank and the auxiliary heating device.
11. Quality assurance: The 10-Group Classification System (Robson classification), induction of labor, and cesarean delivery.
LENUS (Irish Health Repository)
Robson, Michael
2015-10-01
Quality assurance in labor and delivery is needed. The method must be simple and consistent, and be of universal value. It needs to be clinically relevant, robust, and prospective, and must incorporate epidemiological variables. The 10-Group Classification System (TGCS) is a simple method providing a common starting point for further detailed analysis within which all perinatal events and outcomes can be measured and compared. The system is demonstrated in the present paper using data for 2013 from the National Maternity Hospital in Dublin, Ireland. Interpretation of the classification can be easily taught. The standard table can provide much insight into the philosophy of care in the population of women studied and also provide information on data quality. With standardization of audit of events and outcomes, any differences in either sizes of groups, events or outcomes can be explained only by poor data collection, significant epidemiological variables, or differences in practice. In April 2015, WHO proposed that the TGCS (also known as the Robson classification) is used as a global standard for assessing, monitoring, and comparing cesarean delivery rates within and between healthcare facilities.
12. Systems Competence: Operationalization, Evaluation and Theoretic Classification
OpenAIRE
Paukert, Marco
2011-01-01
This thesis pursues the question of how trainings for counseling competences have to be laid out to be effective and how evaluation procedures have to be set up to capture the competence development in this field. The construct systems competence is the starting point for these thoughts. It lists the competences, skills, abilities, and knowledge aspects that are necessary for working with complex, social systems. It is based on the theoretical considerations of Synergetics; a systems theory t...
13. Hotel Classification Systems: A Comparison of International Case Studies
Directory of Open Access Journals (Sweden)
Roberta Minazzi,
2010-12-01
Full Text Available Over the last few decades we have witnessed an increasing interest of scholars andespecially operators in service quality in the lodging business. Firstly, it is important to observe thatthe diverseness of the hospitality industry also affects the classification of hotel quality. We canactually find many programmes, classifications and seals of quality promoted by public authoritiesand private companies that create confusion in the consumer perceptions of hotel quality. Moreover,new electronic distribution channels and their ratings are becoming a new way to gather informationabout a hotel and its quality. Secondly, a point that can cause complications is that different countriesand regions can choose differing approaches depending on the features of the classification (numberof levels, symbols used, etc. and the nature of the programme (public, private. Considering theseassumptions and the recent changes in the Italian hotel classification system, this paper aims toanalyse the situation in Italy, underlining both its positive and negative aspects and comparing it withother European and North American cases. Based on a review of literature and tourism laws as wellas personal interviews with public authorities and exponents of the private sectors, we were able toidentify critical issues and trends in hotel classification systems. The comparison of case studiesshows a heterogeneous situation. Points in common are the scale and the symbol used but, if weanalyse the requirements of each category, we discover very different circumstances, also sometimesin the same country. A future European classification system could be possible only after astandardization of minimum requirements and criteria at a national level. In this situation brands andonline consumers’ feedbacks become even more considered by the customers in the hospitalityindustry.
14. A Classification of Adaptive Feedback in Educational Systems for Programming
OpenAIRE
Nguyen-Thinh Le
2016-01-01
Over the last three decades, many educational systems for programming have been developed to support learning/teaching programming. In this paper, feedback types that are supported by existing educational systems for programming are classified. In order to be able to provide feedback, educational systems for programming deployed various approaches to analyzing students’ programs. This paper identifies analysis approaches for programs and introduces a classification for adaptive feedback suppo...
15. The Nature of the Physical Microenvironment: An Expanded Classification System.
Science.gov (United States)
Wachs, Theodore D.
1989-01-01
Develops a classification system for the physical environment based on 3 dimensions of stimulation. Intercorrelations of physical and social environmental measures obtained for 88 infants of 12 months supported the validity of the decision rule that nonresponsive animate stimulation is primarily physical rather than social. (RJC)
16. Image interpretation for a multilevel land use classification system
Science.gov (United States)
1973-01-01
The potential use is discussed of three remote sensors for developing a four level land use classification system. Three types of imagery for photointerpretation are presented: ERTS-1 satellite imagery, high altitude photography, and medium altitude photography. Suggestions are given as to which remote sensors and imagery scales may be most effectively employed to provide data on specific types of land use.
17. The Spinal Cord Injury-Interventions Classification System
NARCIS (Netherlands)
van Langeveld, A.H.B.
2010-01-01
Title: The Spinal Cord Injury-Interventions Classification System: development and evaluation of a documentation tool to record therapy to improve mobility and self-care in people with spinal cord injury. Background: Many rehabilitation researchers have emphasized the need to examine the actual cont
18. Classification system for conventional crown and fixed partial denture failures.
Science.gov (United States)
Manappallil, John Joy
2008-04-01
The dental literature is replete with reports on the many aspects of failure encountered with traditional fixed prosthodontic treatment, including longitudinal survival studies of crowns and fixed partial dentures and reasons for failures. However, criteria for grading or classifying the type and severity of these failures are inadequate. A classification system for conventional fixed prosthodontic failures based on severity is presented.
19. Ergoterapeutiske ADL-indsatser på akut psykiatrisk hospital
DEFF Research Database (Denmark)
Nielsen, Kristina Tomra; Petersen, Rikke; Decker, Lone
2015-01-01
Det første kapitel i bogen omhandler ADL-begrebet såvel på engelsk som dansk og præsenterer relevante definitioner i et historisk samt tværfagligt og ergoterapeutisk perspektiv. I de efterfølgende kapitler får man et godt indtryk af, hvordan der arbejdes med ADL bredt set, og hvilke metoder og re...
20. BIOPHARMACEUTICS CLASSIFICATION SYSTEM: A STRATEGIC TOOL FOR CLASSIFYING DRUG SUBSTANCES
Directory of Open Access Journals (Sweden)
Rohilla Seema
2011-07-01
Full Text Available The biopharmaceutical classification system (BCS is a scientific approach for classifying drug substances based on their dose/solubility ratio and intestinal permeability. The BCS has been developed to allow prediction of in vivo pharmacokinetic performance of drug products from measurements of permeability and solubility. Moreover, the drugs can be categorized into four classes of BCS on the basis of permeability and solubility namely; high permeability high solubility, high permeability low solubility, low permeability high solubility and low permeability low solubility. The present review summarizes the principles, objectives, benefits, classification and applications of BCS.
1. Standard practice for classification of computed radiology systems
CERN Document Server
American Society for Testing and Materials. Philadelphia
2005-01-01
1.1 This practice describes the evaluation and classification of a computed radiography (CR) system, a particular phosphor imaging plate (IP), system scanner and software, in combination with specified metal screens for industrial radiography. It is intended to ensure that the evaluation of image quality, as far as this is influenced by the scanner/IP system, meets the needs of users. 1.2 The practice defines system tests to be used to classify the systems of different suppliers and make them comparable for users. 1.3 The CR system performance is described by signal and noise parameters. For film systems, the signal is represented by gradient and the noise by granularity. The signal-to-noise ratio is normalized by the basic spatial resolution of the system and is part of classification. The normalization is given by the scanning aperture of 100 µm diameter for the micro-photometer, which is defined in Test Method E1815 for film system classification. This practice describes how the parameters shall be meas...
2. On a production system using default reasoning for pattern classification
Science.gov (United States)
Barry, Matthew R.; Lowe, Carlyle M.
1990-01-01
This paper addresses an unconventional application of a production system to a problem involving belief specialization. The production system reduces a large quantity of low-level descriptions into just a few higher-level descriptions that encompass the problem space in a more tractable fashion. This classification process utilizes a set of descriptions generated by combining the component hierarchy of a physical system with the semantics of the terminology employed in its operation. The paper describes an application of this process in a program, constructed in C and CLIPS, that classifies signatures of electromechanical system configurations. The program compares two independent classifications, describing the actual and expected system configurations, in order to generate a set of contradictions between the two.
3. Intrusion Detection System with Hierarchical Different Parallel Classification
Directory of Open Access Journals (Sweden)
2015-12-01
Full Text Available Todays, lives integrated to networks and internet. The needed information is transmitted through networks. So, someone may attempt to abuse the information and attack and make changes by weakness of networks. Intrusion Detection System is a system capable to detect some attacks. The system detects attacks through classifier construction and considering IP in network. The recent researches showed that a fundamental classification cannot be effective lonely and due to its errors, but mixing some classifications provide better efficiency. So, the current study attempt to design three classes of support vector machine, the neural network of multilayer perceptron and parallel fuzzy system in which there are trained dataset and capability to detect two classes. Finally, decisions made by an intermediate network due to type of attack. In the present research, suggested system tested through dataset of KDD99 and results indicated appropriate efficiency 99.71% in average.
4. Classification of Recommender Expertise in the Wikipedia Recommender System
DEFF Research Database (Denmark)
Jensen, Christian D.; Pilkauskas, Povilas; Lefevre, Thomas
2011-01-01
The Wikipedia is a web-based encyclopedia, written and edited collaboratively by Internet users. The Wikipedia has an extremely open editorial policy that allows anybody, to create or modify articles. This has promoted a broad and detailed coverage of subjects, but also introduced problems relati...... and present an evaluation of four existing knowledge classification schemes with respect to these requirements. This evaluation helped us identify a classification scheme, which we have implemented in the current version of the Wikipedia Recommender System....... to the quality of articles. The Wikipedia Recommender System (WRS) was developed to help users determine the credibility of articles based on feedback from other Wikipedia users. The WRS implements a collaborative filtering system with trust metrics, i.e., it provides a rating of articles "which...... articles in the Wikipedia. In this paper, we examine different ways to classify the subject area of Wikipedia article according to well established knowledge classification schemes. We identify a number of requirements that a classification scheme must meet in order to be useful in the context of the WRS...
5. Classification of Recommender Expertise in the Wikipedia Recommender System
DEFF Research Database (Denmark)
Jensen, Christian D.; Pilkauskas, Povilas; Lefévre, Thomas
2011-01-01
The Wikipedia is a web-based encyclopedia, written and edited collaboratively by Internet users. The Wikipedia has an extremely open editorial policy that allows anybody, to create or modify articles. This has promoted a broad and detailed coverage of subjects, but also introduced problems relati...... and present an evaluation of four existing knowledge classification schemes with respect to these requirements. This evaluation helped us identify a classification scheme, which we have implemented in the current version of the Wikipedia Recommender System....... to the quality of articles. The Wikipedia Recommender System (WRS) was developed to help users determine the credibility of articles based on feedback from other Wikipedia users. The WRS implements a collaborative filtering system with trust metrics, i.e., it provides a rating of articles which...... articles in the Wikipedia. In this paper, we examine different ways to classify the subject area of Wikipedia article according to well established knowledge classification schemes. We identify a number of requirements that a classification scheme must meet in order to be useful in the context of the WRS...
6. A Classification System for Hospital-Based Infection Outbreaks
Directory of Open Access Journals (Sweden)
Paul S. Ganney
2010-01-01
Full Text Available Outbreaks of infection within semi-closed environments such as hospitals, whether inherent in the environment (such as Clostridium difficile (C.Diff or Methicillinresistant Staphylococcus aureus (MRSA or imported from the wider community (such as Norwalk-like viruses (NLVs, are difficult to manage. As part of our work on modelling such outbreaks, we have developed a classification system to describe the impact of a particular outbreak upon an organization. This classification system may then be used in comparing appropriate computer models to real outbreaks, as well as in comparing different real outbreaks in, for example, the comparison of differing management and containment techniques and strategies. Data from NLV outbreaks in the Hull and East Yorkshire Hospitals NHS Trust (the Trust over several previous years are analysed and classified, both for infection within staff (where the end of infection date may not be known and within patients (where it generally is known. A classification system consisting of seven elements is described, along with a goodness-of-fit method for comparing a new classification to previously known ones, for use in evaluating a simulation against history and thereby determining how ‘realistic’ (or otherwise it is.
7. Creating a Canonical Scientific and Technical Information Classification System for NCSTRL+
Science.gov (United States)
Tiffany, Melissa E.; Nelson, Michael L.
1998-01-01
The purpose of this paper is to describe the new subject classification system for the NCSTRL+ project. NCSTRL+ is a canonical digital library (DL) based on the Networked Computer Science Technical Report Library (NCSTRL). The current NCSTRL+ classification system uses the NASA Scientific and Technical (STI) subject classifications, which has a bias towards the aerospace, aeronautics, and engineering disciplines. Examination of other scientific and technical information classification systems showed similar discipline-centric weaknesses. Traditional, library-oriented classification systems represented all disciplines, but were too generalized to serve the needs of a scientific and technically oriented digital library. Lack of a suitable existing classification system led to the creation of a lightweight, balanced, general classification system that allows the mapping of more specialized classification schemes into the new framework. We have developed the following classification system to give equal weight to all STI disciplines, while being compact and lightweight.
8. Understanding Acupuncture Based on ZHENG Classification from System Perspective
OpenAIRE
Junwei Fang; Ningning Zheng; Yang Wang; Huijuan Cao; Shujun Sun; Jianye Dai; Qianhua Li; Yongyu Zhang
2013-01-01
Acupuncture is an efficient therapy method originated in ancient China, the study of which based on ZHENG classification is a systematic research on understanding its complexity. The system perspective is contributed to understand the essence of phenomena, and, as the coming of the system biology era, broader technology platforms such as omics technologies were established for the objective study of traditional chinese medicine (TCM). Omics technologies could dynamically determine molecular c...
9. Annotation and Classification of CRISPR-Cas Systems.
Science.gov (United States)
Makarova, Kira S; Koonin, Eugene V
2015-01-01
The clustered regularly interspaced short palindromic repeats (CRISPR)-Cas (CRISPR-associated proteins) is a prokaryotic adaptive immune system that is represented in most archaea and many bacteria. Among the currently known prokaryotic defense systems, the CRISPR-Cas genomic loci show unprecedented complexity and diversity. Classification of CRISPR-Cas variants that would capture their evolutionary relationships to the maximum possible extent is essential for comparative genomic and functional characterization of this theoretically and practically important system of adaptive immunity. To this end, a multipronged approach has been developed that combines phylogenetic analysis of the conserved Cas proteins with comparison of gene repertoires and arrangements in CRISPR-Cas loci. This approach led to the current classification of CRISPR-Cas systems into three distinct types and ten subtypes for each of which signature genes have been identified. Comparative genomic analysis of the CRISPR-Cas systems in new archaeal and bacterial genomes performed over the 3 years elapsed since the development of this classification makes it clear that new types and subtypes of CRISPR-Cas need to be introduced. Moreover, this classification system captures only part of the complexity of CRISPR-Cas organization and evolution, due to the intrinsic modularity and evolutionary mobility of these immunity systems, resulting in numerous recombinant variants. Moreover, most of the cas genes evolve rapidly, complicating the family assignment for many Cas proteins and the use of family profiles for the recognition of CRISPR-Cas subtype signatures. Further progress in the comparative analysis of CRISPR-Cas systems requires integration of the most sensitive sequence comparison tools, protein structure comparison, and refined approaches for comparison of gene neighborhoods.
10. CLASSIFICATION OF THE MGR SITE RADIOLOGICAL MONITORING SYSTEM
International Nuclear Information System (INIS)
The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) site radiological monitoring system structures, systems and components (SSCs) performed by the MGR Safety Assurance Department. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 1998). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P, ''Quality Assurance Requirements and Description'' (QARD) (DOE 1998)
11. Algorithm integration using ADL (Algorithm Development Library) for improving CrIMSS EDR science product quality
Science.gov (United States)
Das, B.; Wilson, M.; Divakarla, M. G.; Chen, W.; Barnet, C.; Wolf, W.
2013-05-01
Algorithm Development Library (ADL) is a framework that mimics the operational system IDPS (Interface Data Processing Segment) that is currently being used to process data from instruments aboard Suomi National Polar-orbiting Partnership (S-NPP) satellite. The satellite was launched successfully in October 2011. The Cross-track Infrared and Microwave Sounder Suite (CrIMSS) consists of the Advanced Technology Microwave Sounder (ATMS) and Cross-track Infrared Sounder (CrIS) instruments that are on-board of S-NPP. These instruments will also be on-board of JPSS (Joint Polar Satellite System) that will be launched in early 2017. The primary products of the CrIMSS Environmental Data Record (EDR) include global atmospheric vertical temperature, moisture, and pressure profiles (AVTP, AVMP and AVPP) and Ozone IP (Intermediate Product from CrIS radiances). Several algorithm updates have recently been proposed by CrIMSS scientists that include fixes to the handling of forward modeling errors, a more conservative identification of clear scenes, indexing corrections for daytime products, and relaxed constraints between surface temperature and air temperature for daytime land scenes. We have integrated these improvements into the ADL framework. This work compares the results from ADL emulation of future IDPS system incorporating all the suggested algorithm updates with the current official processing results by qualitative and quantitative evaluations. The results prove these algorithm updates improve science product quality.
12. General classification handbook for floodplain vegetation in large river systems
Science.gov (United States)
Dieck, Jennifer J.; Ruhser, Janis; Hoy, Erin E.; Robinson, Larry R.
2015-01-01
This handbook describes the General Wetland Vegetation Classification System developed as part of the U.S. Army Corps of Engineers’ Upper Mississippi River Restoration (UMRR) Program, Long Term Resource Monitoring (LTRM) element. The UMRR is a cooperative effort between the U.S. Army Corps of Engineers, U.S. Geological Survey, U.S. Fish and Wildlife Service, and the states of Illinois, Iowa, Minnesota, Missouri, and Wisconsin. The classification system consists of 31 general map classes and has been used to create systemic vegetation data layers throughout the diverse Upper Mississippi River System (UMRS), which includes the commercially navigable reaches of the Mississippi River from Minneapolis, Minnesota, in the north to Cairo, Illinois, in the south, the Illinois River, and navigable portions of the Kaskaskia, Black, St. Croix, and Minnesota Rivers. In addition, this handbook describes the evolution of the General Wetland Vegetation Classification System, discusses the process of creating a vegetation data layer, and describes each of the 31 map classes in detail. The handbook also acts as a pictorial guide to each of the map classes as they may appear in the field, as well as on color-infrared imagery. This version is an update to the original handbook published in 2004.
13. Selecting Quasar Candidates by a SVM Classification System
CERN Document Server
Peng, Nanbo; Zhao, Yongheng; Wu, Xuebing
2012-01-01
We develop and demonstrate a classification system constituted by several Support Vector Machines (SVM) classifiers, which can be applied to select quasar candidates from large sky survey projects, such as SDSS, UKIDSS, GALEX. How to construct this SVM classification system is presented in detail. When the SVM classification system works on the test set to predict quasar candidates, it acquires the efficiency of 93.21% and the completeness of 97.49%. In order to further prove the reliability and feasibility of this system, two chunks are randomly chosen to compare its performance with that of the XDQSO method used for SDSS-III's BOSS. The experimental results show that the high faction of overlap exists between the quasar candidates selected by this system and those extracted by the XDQSO technique in the dereddened i-band magnitude range between 17.75 and 22.45, especially in the interval of dereddened i-band magnitude < 20.0. In the two test areas, 57.38% and 87.15% of the quasar candidates predicted by ...
14. LANGUAGE SYSTEM AS NATURAL MULTILEVEL HIGH-RELIABILITY CLASSIFICATION
Directory of Open Access Journals (Sweden)
Ирина Михайловна Некипелова
2013-09-01
Full Text Available Classification of language presupposes its standardization. The conception of artificial standardization should be distinguished from natural standardization. The artificial standardization makes by society, pressing on language and making it more universal, but slowing down its development. The natural classification is inner aspiration of language system to be a universal mean for communication. This processes correlate to each other, but they are realized by different mechanisms. The natural standardization realizes needs of all society, and the artificial – needs of science community and state. In that case, when artificial standardization of language becomes to curb and restrain natural development of language system. Opposition between artificial and natural processes of standardization is come. As of a result of it scientists register weak language culture of population. But it is just the result of divergence of standards: natural, reflecting back needs of society, and artificial, reflecting back requirements to proficiency in a language. In whole, classification is one of the basic, fundamental method of cognition. Individual begins mastering of language from infancy and it is been conditional on predominance of classifying way of comprehension of phenomena of the world in the first years of life. In the process of language mastering, offering by society, an individual strives for, on the one hand, to correspond to standard language characteristics, on the other hand, to express his identity. In this respect language is not only classification, but classifier, because it detects further direction of human thinking in the field of building of classification of language. The research showed that logic operations of synthesis and analysis – being the fundamental of classification method - make it possible to comprehend language as system, which units interact to each other permanently. Openness and simplicity of the method enable
15. 78 FR 18252 - Prevailing Rate Systems; North American Industry Classification System Based Federal Wage System...
Science.gov (United States)
2013-03-26
... survey industry regulations with the 2007 NAICS revisions published by the Office of Management and... From the Federal Register Online via the Government Publishing Office #0; #0;Proposed Rules #0... Industry Classification System Based Federal Wage System Wage Surveys AGENCY: U. S. Office of...
16. Nasal Septal Deviations: A Systematic Review of Classification Systems
Science.gov (United States)
Teixeira, Jeffrey; Certal, Victor; Chang, Edward T.; Camacho, Macario
2016-01-01
Objective. To systematically review the international literature for internal nasal septal deviation classification systems and summarize them for clinical and research purposes. Data Sources. Four databases (including PubMed/MEDLINE) were systematically searched through December 16, 2015. Methods. Systematic review, adhering to PRISMA. Results. After removal of duplicates, this study screened 952 articles for relevance. A final comprehensive review of 50 articles identified that 15 of these articles met the eligibility criteria. The classification systems defined in these articles included C-shaped, S-shaped, reverse C-shaped, and reverse S-shaped descriptions of the septal deviation in both the cephalocaudal and anteroposterior dimensions. Additional studies reported use of computed tomography and categorized deviation based on predefined locations. Three studies graded the severity of septal deviations based on the amount of deflection. The systems defined in the literature also included an evaluation of nasal septal spurs and perforations. Conclusion. This systematic review ascertained that the majority of the currently published classification systems for internal nasal septal deviations can be summarized by C-shaped or reverse C-shaped, as well as S-shaped or reverse S-shaped deviations in the anteroposterior and cephalocaudal dimensions. For imaging studies, predefined points have been defined along the septum. Common terminology can facilitate future research. PMID:26933510
17. Nasal Septal Deviations: A Systematic Review of Classification Systems
Directory of Open Access Journals (Sweden)
Jeffrey Teixeira
2016-01-01
Full Text Available Objective. To systematically review the international literature for internal nasal septal deviation classification systems and summarize them for clinical and research purposes. Data Sources. Four databases (including PubMed/MEDLINE were systematically searched through December 16, 2015. Methods. Systematic review, adhering to PRISMA. Results. After removal of duplicates, this study screened 952 articles for relevance. A final comprehensive review of 50 articles identified that 15 of these articles met the eligibility criteria. The classification systems defined in these articles included C-shaped, S-shaped, reverse C-shaped, and reverse S-shaped descriptions of the septal deviation in both the cephalocaudal and anteroposterior dimensions. Additional studies reported use of computed tomography and categorized deviation based on predefined locations. Three studies graded the severity of septal deviations based on the amount of deflection. The systems defined in the literature also included an evaluation of nasal septal spurs and perforations. Conclusion. This systematic review ascertained that the majority of the currently published classification systems for internal nasal septal deviations can be summarized by C-shaped or reverse C-shaped, as well as S-shaped or reverse S-shaped deviations in the anteroposterior and cephalocaudal dimensions. For imaging studies, predefined points have been defined along the septum. Common terminology can facilitate future research.
18. Side effects of cancer therapies. International classification and documentation systems
International Nuclear Information System (INIS)
The publication presents and explains verified, international classification and documentation systems for side effects induced by cancer treatments, applicable in general and clinical practice and clinical research, and covers in a clearly arranged manner the whole range of treatments, including acute and chronic side effects of chemotherapy and radiotherapy, surgery, or combined therapies. The book fills a long-felt need in tumor documentation and is a major contribution to quality assurance in clinical oncology in German-speaking countries. As most parts of the book are bilingual, presenting German and English texts and terminology, it satisfies the principles of interdisciplinarity and internationality. The tabulated form chosen for presentation of classification systems and criteria facilitate the user's approach as well as application in daily work. (orig./CB)
19. Danish translation and validation of the International Skin Tear Advisory Panel Skin Tear Classification System
DEFF Research Database (Denmark)
Skiveren, J; Bermark, S; LeBlanc, K;
2015-01-01
OBJECTIVE: The aim of this study was to translate, validate and establish reliability of the International Skin Tear Classification System in Danish. METHOD: Phase 1 of the project involved the translation of the International Skin Tear Advisory Panel (ISTAP) Skin Tear Classification System into ...... the earlier ISTAP study and further validates the classification system. The Danish translation of the classification system is vital to the promotion of skin tears in both research and the clinical settings in Denmark....
20. Classification of Transient Phenomena in Distribution System using wavelet Transform
Science.gov (United States)
Sedighi, Alireza
2014-05-01
An efficient procedure for classification of transient phenomena in distribution systems is proposed in this paper. The proposed method has been applied to classify some transient phenomena such as inrush current, load switching, capacitor switching and single phase to ground fault. The new scheme is based on wavelet transform algorithm. All of the events for feature extraction and test are simulated using Electro Magnetic Transient Program (EMTP). Results show high accuracy of proposed method.
1. A classification system for tableting behaviors of binary powder mixtures
OpenAIRE
Changquan Calvin Sun
2016-01-01
The ability to predict tableting properties of a powder mixture from individual components is of both fundamental and practical importance to the efficient formulation development of tablet products. A common tableting classification system (TCS) of binary powder mixtures facilitates the systematic development of new knowledge in this direction. Based on the dependence of tablet tensile strength on weight fraction in a binary mixture, three main types of tableting behavior are identified. Eac...
2. Derivation and validation of the Systemic Lupus International Collaborating Clinics classification criteria for systemic lupus erythematosus
DEFF Research Database (Denmark)
Petri, Michelle; Orbai, Ana-Maria; Alarcón, Graciela S;
2012-01-01
The Systemic Lupus International Collaborating Clinics (SLICC) group revised and validated the American College of Rheumatology (ACR) systemic lupus erythematosus (SLE) classification criteria in order to improve clinical relevance, meet stringent methodology requirements, and incorporate new kno...
3. Derivation and validation of the Systemic Lupus International Collaborating Clinics classification criteria for systemic lupus erythematosus
DEFF Research Database (Denmark)
Petri, Michelle; Orbai, Ana-Maria; Alarcón, Graciela S;
2012-01-01
The Systemic Lupus International Collaborating Clinics (SLICC) group revised and validated the American College of Rheumatology (ACR) systemic lupus erythematosus (SLE) classification criteria in order to improve clinical relevance, meet stringent methodology requirements, and incorporate new...
4. THE BIOPHARMACEUTICAL CLASSIFICATION SYSTEM (BCS: PRESENT STATUS AND FUTURE PROSPECTIVES
Directory of Open Access Journals (Sweden)
Budhwaar Vikaas
2012-09-01
Full Text Available The Biopharmaceutical classification system (BCS was introduced By Amidon et al., (1995 as a method for classifying drug substances based on their dose/solubility ratio and intestinal permeability. It allows predicting the in vivo pharmacokinetic performance of drug products. The drug can be categorized into four classes of BCS, namely, High solubility high permeability, low solubility high permeability, High solubility low permeability and low solubility low permeability. An objective of BCS approach is to determine the equilibrium solubility of drug substances under physiological environment. The BCS helps in mathematically analyzing the kinetics and dynamics of drug in gastrointestinal tract (GIT for New Drug Applications (NDA and Abbreviated New Drug Applications (ANDA filings and biowaivers. This step reduces time in the new drug development process. Further it helps to decide when the dissolution rate is likely to be the rate determining step. It also helps in the prediction of potential of inactive ingredients in the dosage form to alter the dissolution / absorption of the drug. The present review, apart from giving a brief overview of BCS classification system, highlights these and some of the more recent applications of BCS classification system.
5. 5 CFR 9901.231 - Conversion of positions and employees to NSPS classification system.
Science.gov (United States)
2010-01-01
... NSPS classification system. 9901.231 Section 9901.231 Administrative Personnel DEPARTMENT OF DEFENSE... MANAGEMENT) DEPARTMENT OF DEFENSE NATIONAL SECURITY PERSONNEL SYSTEM (NSPS) Classification Transitional Provisions § 9901.231 Conversion of positions and employees to NSPS classification system. (a)...
6. 42 CFR 412.10 - Changes in the DRG classification system.
Science.gov (United States)
2010-10-01
... 42 Public Health 2 2010-10-01 2010-10-01 false Changes in the DRG classification system. 412.10... § 412.10 Changes in the DRG classification system. (a) General rule. CMS issues changes in the DRG classification system in a Federal Register notice at least annually. Except as specified in paragraphs (c)...
7. CLASSIFICATION OF THE MGR CARRIER PREPARATION BUILDING MATERIALS HANDLING SYSTEM
Energy Technology Data Exchange (ETDEWEB)
J.A. Ziegler
2001-02-08
The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) carrier preparation building materials handling system structures, systems and components (SSCs) performed by the MGR Preclosure Safety and Systems Engineering Section. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 2000). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P7 ''Quality Assurance Requirements and Description'' (QARD) (DOE 2000).
8. CLASSIFICATION OF THE MGR CARRIER/CASK HANDLING SYSTEM
Energy Technology Data Exchange (ETDEWEB)
J.A. Ziegler
2001-02-08
The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) carried cask handling system structures, systems and components (SSCs) performed by the MGR Preclosure Safety and Systems Engineering Section. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 2000). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P, ''Quality Assurance Requirements and Description'' (QARD) (DOE 2000).
9. CLASSIFICATION OF THE MGR WASTE PACKAGE REMEDIATION SYSTEM
Energy Technology Data Exchange (ETDEWEB)
J.A. Ziegler
2000-11-02
The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) waste package remediation system structures, systems, and components (SSCs) performed by the MGR Preclosure Safety and Systems Engineering Section. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 2000). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P7 ''Quality Assurance Requirements and Description'' (QARD) (DOE 2000).
10. Classification of Unmanned Aircraft Systems. UAS Classification/Categorization for Certification
Science.gov (United States)
2004-01-01
Category, class, and type designations are primary means to identify appropriate aircraft certification basis, operating rules/limitations, and pilot qualifications to operate in the National Airspace System (NAS). The question is whether UAS fit into existing aircraft categories or classes, or are unique enough to justify the creation of a new category/class. In addition, the characteristics or capabilities, which define when an UAS becomes a regulated aircraft, must also be decided. This issue focuses on UAS classification for certification purposes. Several approaches have been considered for classifying UAS. They basically group into either using a weight/mass basis, or a safety risk basis, factoring in the performance of the UAS, including where the UAS would operate. Under existing standards, aircraft must have a Type Certificate and Certificate of Airworthiness, in order to be used for "compensation or hire", a major difference from model aircraft. Newer technologies may make it possible for very small UAS to conduct commercial services, but that is left for a future discussion to extend the regulated aircraft to a lower level. The Access 5 position is that UAS are aircraft and should be regulated above the weight threshold differentiating them from model airplanes. The recommended classification grouping is summarized in a chart.
11. On the Origins of the Quinarian System of Classification.
Science.gov (United States)
Novick, Aaron
2016-02-01
William Sharp Macleay developed the quinarian system of classification in his Horæ Entomologicæ, published in two parts in 1819 and 1821. For two decades, the quinarian system was widely discussed in Britain and influenced such naturalists as Charles Darwin, Richard Owen, and Thomas Huxley. This paper offers the first detailed account of Macleay's development of the quinarian system. Macleay developed his system under the shaping influence of two pressures: (1) the insistence by followers of Linnaeus on developing artificial systems at the expense of the natural system and (2) the apparent tension between the continuity of organic nature and the failure of linear classification schemes (which continuity seemed to require). Against what he perceived as dogmatic indolence on the part of the Linnaeans, Macleay developed a philosophy of science in which hypotheses that exceeded the available evidence should be proposed and subjected to severe tests. He also developed a novel comparative anatomical methodology, the method of variation, to aid in his search for the natural system. Using this method, he developed an intricate system that showed how organic nature could be continuous without being linear. A failure to appreciate these facets of Macleay's thought has led to several misunderstandings of him and his work, most notably that he was an idealist. These misunderstandings are here rebutted.
12. A classification system for conditions causing condylar hyperplasia.
Science.gov (United States)
Wolford, Larry M; Movahed, Reza; Perez, Daniel E
2014-03-01
A classification system was developed to place patients with condylar hyperplasia (CH) into categories based on histology, clinical and imaging characteristics, effects on the jaws and facial structures, and rate of occurrence. Four major categories were defined. CH type 1 is an accelerated and prolonged growth aberration of the "normal" mandibular condylar growth mechanism, causing a predominantly horizontal growth vector, resulting in prognathism that can occur bilaterally (CH type 1A) or unilaterally (CH type 1B). CH type 2 refers to enlargement of the mandibular condyle caused by an osteochondroma, resulting in predominantly unilateral vertical overgrowth and elongation of the mandible and face. One of the forms has predominantly a vertical growth vector and condylar enlargement, but without exophytic tumor extensions (type 2A), whereas the other primary form grows vertically but develops horizontal exophytic tumor growth off of the condyle (CH type 2B). CH type 3 includes other rare, benign tumors and CH type 4 includes malignant conditions that originate in the mandibular condyle causing enlargement. The order of classification is based on occurrence rates and type of pathology, where CH type 1A is the most commonly occurring form and CH type 4 is the rarest. This classification system for CH pathology should help the clinician understand the nature of the pathology, progression if untreated, recommended ages for surgical intervention to minimize adverse effects on subsequent facial growth and development in younger patients, and the surgical protocols to comprehensively and predictably treat these conditions. PMID:24388179
13. An alternative respiratory sounds classification system utilizing artificial neural networks
Directory of Open Access Journals (Sweden)
Rami J Oweis
2015-04-01
Full Text Available Background: Computerized lung sound analysis involves recording lung sound via an electronic device, followed by computer analysis and classification based on specific signal characteristics as non-linearity and nonstationarity caused by air turbulence. An automatic analysis is necessary to avoid dependence on expert skills. Methods: This work revolves around exploiting autocorrelation in the feature extraction stage. All process stages were implemented in MATLAB. The classification process was performed comparatively using both artificial neural networks (ANNs and adaptive neuro-fuzzy inference systems (ANFIS toolboxes. The methods have been applied to 10 different respiratory sounds for classification. Results: The ANN was superior to the ANFIS system and returned superior performance parameters. Its accuracy, specificity, and sensitivity were 98.6%, 100%, and 97.8%, respectively. The obtained parameters showed superiority to many recent approaches. Conclusions: The promising proposed method is an efficient fast tool for the intended purpose as manifested in the performance parameters, specifically, accuracy, specificity, and sensitivity. Furthermore, it may be added that utilizing the autocorrelation function in the feature extraction in such applications results in enhanced performance and avoids undesired computation complexities compared to other techniques.
14. Improved Classification Methods for Brain Computer Interface System
Directory of Open Access Journals (Sweden)
YI Fang
2012-03-01
Full Text Available Brain computer interface (BCI aims at providing a new communication way without brain’s normal output through nerve and muscle. The electroencephalography (EEG has been widely used for BCI system because it is a non-invasive approach. For the EEG signals of left and right hand motor imagery, the event-related desynchronization (ERD and event-related synchronization(ERS are used as classification features in this paper. The raw data are transformed by nonlinear methods and classified by Fisher classifier. Compared with the linear methods, the classification accuracy can get an obvious increase to 86.25%. Two different nonlinear transform were arised and one of them is under the consideration of the relativity of two channels of EEG signals. With these nonlinear transform, the performance are also stable with the balance of two misclassifications.
15. The measurement of instrumental ADL: content validity and construct validity
DEFF Research Database (Denmark)
Avlund, K; Schultz-Larsen, K; Kreiner, S
1993-01-01
A new measure of Instrumental Activities of Daily Living (IADL), which is able to discriminate among the large group of elderly who do not depend on help, was tested for content validity and construct validity. Most assessments of functional ability include Physical ADL (PADL) and Instrumental ADL....... The measure of Instrumental ADL included 30 activities in relation to tiredness and reduced speed. Construct validity was tested by the Rasch model for item analysis; internal validity was specifically addressed by assessing the homogeneity of items under different conditions. The Rasch item analysis of IADL...... showed that 14 items could be combined into two qualitatively different additive scales. The IADL-measure complies with demands for content validity, distinguishes between what the elderly actually do, and what they are capable of doing, and is a good discriminator among the group of elderly persons who...
16. Nominal classification
OpenAIRE
Senft, G.
2007-01-01
This handbook chapter summarizes some of the problems of nominal classification in language, presents and illustrates the various systems or techniques of nominal classification, and points out why nominal classification is one of the most interesting topics in Cognitive Linguistics.
17. Classification of healthcare systems: Can we go further?
Science.gov (United States)
Toth, Federico
2016-05-01
This article addresses the issue of the classification of healthcare systems, with the intent to take a step further than the previously analysed models of healthcare organisation. As concerns the financing of healthcare services, the standard tripartite classification (according to which healthcare systems are divided into three groups: voluntary insurance, social health insurance and universal coverage) is enriched with two additional types: compulsory national health insurance and residual programs. With respect to the provision of services and the relationship between insurers and providers, it is important to distinguish between vertically integrated and separated systems. What differentiates this analysis from the majority of previous studies is its underlying logic. Assuming that all systems are hybrid, the article proposes to put aside the classic logic for classifying healthcare systems (according to which individual countries are pigeonholed into different classes depending on the prevailing system) in favour of the identikit logic. The concept of segmentation (of healthcare services or population) proves to be remarkably useful to this purpose. PMID:27041537
18. Quantitative Assessment of ADL: A Pilot Study of Upper Extremity Reaching Tasks
Directory of Open Access Journals (Sweden)
Saiyi Li
2015-01-01
Full Text Available Effective telerehabilitation technologies enable patients with certain physiological disabilities to engage in rehabilitative exercises for performing Activities of Daily Living (ADLs. Therefore, training and assessment scenarios for the performance of ADLs are vital for the promotion for telerehabilitation. In this paper we investigate quantitatively and automatically assessing patient’s kinematic ability to perform functional upper extremity reaching tasks. The shape of the movement trajectory and the instantaneous acceleration of kinematically crucial body parts, such as wrists, are used to compute the approximate entropy of the motions to represent stability (smoothness in addition to the duration of the activity. Computer simulations were conducted to illustrate the consistency, sensitivity and robustness of the proposed method. A preliminary experiment with kinematic data captured from healthy subjects mimicking a reaching task with dyskinesia showed a high degree of correlation (Cohen’s kappa 0.85 with p<0.05 between a human observer and the proposed automatic classification tool in terms of assigning the datasets to various levels to represent the subjects’ kinematic abilities to perform reaching tasks. This study supported the use of Microsoft Kinect to quantitatively evaluate the ability of individuals with involuntary movements to perform an upper extremity reaching task.
19. Analytical models and system topologies for remote multispectral data acquisition and classification
Science.gov (United States)
Huck, F. O.; Park, S. K.; Burcher, E. E.; Kelly, W. L., IV
1978-01-01
Simple analytical models are presented of the radiometric and statistical processes that are involved in multispectral data acquisition and classification. Also presented are basic system topologies which combine remote sensing with data classification. These models and topologies offer a preliminary but systematic step towards the use of computer simulations to analyze remote multispectral data acquisition and classification systems.
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5. Self-reported quality of ADL task performance among patients with COPD exacerbations
DEFF Research Database (Denmark)
Bendixen, Hans Jørgen; Wæhrens, Eva Ejlersen; Wilcke, Jon Torgny;
2014-01-01
Lifescience Database Archive (English)
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13. Neighborhood Hypergraph Based Classification Algorithm for Incomplete Information System
Directory of Open Access Journals (Sweden)
Feng Hu
2015-01-01
Full Text Available The problem of classification in incomplete information system is a hot issue in intelligent information processing. Hypergraph is a new intelligent method for machine learning. However, it is hard to process the incomplete information system by the traditional hypergraph, which is due to two reasons: (1 the hyperedges are generated randomly in traditional hypergraph model; (2 the existing methods are unsuitable to deal with incomplete information system, for the sake of missing values in incomplete information system. In this paper, we propose a novel classification algorithm for incomplete information system based on hypergraph model and rough set theory. Firstly, we initialize the hypergraph. Second, we classify the training set by neighborhood hypergraph. Third, under the guidance of rough set, we replace the poor hyperedges. After that, we can obtain a good classifier. The proposed approach is tested on 15 data sets from UCI machine learning repository. Furthermore, it is compared with some existing methods, such as C4.5, SVM, NavieBayes, and KNN. The experimental results show that the proposed algorithm has better performance via Precision, Recall, AUC, and F-measure.
14. Reporting ureteroscopy complications using the modified clavien classification system
Directory of Open Access Journals (Sweden)
Ahmed Khalil Ibrahim
2015-01-01
Full Text Available Objective: Perioperative complications are one of the surrogate indicators of surgical outcomes. However, reporting these complications need a precise grading system. Our aim is to report and grade the complications of semirigid ureteroscopy in ureteral stone management according to the modified Clavien classification system. Materials and Methods: This is a prospective study conducted From January 2012 to June 2013. All patients with ureteral stones who were indicated for semirigid URS were evaluated. All procedures were performed by the same surgeon. The data recorded including patient demographics, clinical indication, stone size and location, operative time and complications were classified according to the modified Clavien classification system. The patients were followed for 8 weeks postoperatively. Results: 148 patients included, Stone distribution was: 89 (60.1% lower ureteral, 26 (17.6% mid ureteral, and 33 (22.3% upper ureteral. the mean stone size was 8.6 mm. Urgent URS done in 23% of patient. The overall stone free rate was 88.5%, the individual stone free rate for the upper, middle and lower ureter were 87.9%, 84.6%, and 89.9%, respectively. The mean operative time was 31.9 min (20-50 min.. Complications occurred in 26.35% of patients. Grade I complications occurred in 32 patients (26.1%, grade II in 9 (6.1%, grade IIIa in 7 (4.7%, grade IIIb in 8 (5.4%, grade IVa in two patient (1.35%, and grade IVb in one patient (0.7%. No grade V complication was encountered. Conclusion: Ureteroscopy becomes the vanguard interventional therapy for ureteral stones with well-established efficacy and safety. It is of paramount importance to adopt a precise structured classification system for reporting surgical complications, that should be flexible and comprehensive in order to accommodate the various and rapidly expanding surgical fields.
15. The Bellevue Classification System: nursing's voice upon the library shelves*†
OpenAIRE
Mages, Keith C
2011-01-01
This article examines the inspiration, construction, and meaning of the Bellevue Classification System (BCS), created during the 1930s for use in the Bellevue School of Nursing Library. Nursing instructor Ann Doyle, with assistance from librarian Mary Casamajor, designed the BCS after consulting with library leaders and examining leading contemporary classification systems, including the Dewey Decimal Classification and Library of Congress, Ballard, and National Health Library classification ...
16. Computer aided decision support system for cervical cancer classification
Science.gov (United States)
2012-10-01
Conventional analysis of a cervical histology image, such a pap smear or a biopsy sample, is performed by an expert pathologist manually. This involves inspecting the sample for cellular level abnormalities and determining the spread of the abnormalities. Cancer is graded based on the spread of the abnormal cells. This is a tedious, subjective and time-consuming process with considerable variations in diagnosis between the experts. This paper presents a computer aided decision support system (CADSS) tool to help the pathologists in their examination of the cervical cancer biopsies. The main aim of the proposed CADSS system is to identify abnormalities and quantify cancer grading in a systematic and repeatable manner. The paper proposes three different methods which presents and compares the results using 475 images of cervical biopsies which include normal, three stages of pre cancer, and malignant cases. This paper will explore various components of an effective CADSS; image acquisition, pre-processing, segmentation, feature extraction, classification, grading and disease identification. Cervical histological images are captured using a digital microscope. The images are captured in sufficient resolution to retain enough information for effective classification. Histology images of cervical biopsies consist of three major sections; background, stroma and squamous epithelium. Most diagnostic information are contained within the epithelium region. This paper will present two levels of segmentations; global (macro) and local (micro). At the global level the squamous epithelium is separated from the background and stroma. At the local or cellular level, the nuclei and cytoplasm are segmented for further analysis. Image features that influence the pathologists' decision during the analysis and classification of a cervical biopsy are the nuclei's shape and spread; the ratio of the areas of nuclei and cytoplasm as well as the texture and spread of the abnormalities
17. A Meter Classification System for Spoken Persian Poetries
Directory of Open Access Journals (Sweden)
Saeid Hamidi & Farbod Razzazi
2011-11-01
Full Text Available In this article, a meter classification system has been proposed for Persian poems based onfeatures that are extracted from uttered poem. In the first stage, the utterance has beensegmented into syllables using three features, pitch frequency and modified energy of each frameof the utterance and its temporal variations. In the second stage, each syllable is classified intolong syllable and short syllable classes which is a historically convenient categorization in Persianliterature. In this stage, the classifier is an SVM classifier with radial basis function kernel. Theemployed features are the syllable temporal duration, zero crossing rate and PARCORcoefficients of each syllable. The sequence of extracted syllables classes is then softly comparedwith classic Persian meter styles using dynamic time warping, to make the system robust againstsyllables insertion, deletion or classification and poems authorities. The system has beenevaluated on 136 poetries utterances from 12 Persian meter styles gathered from 8 speakers,using k-fold evaluation strategy. The results show 91% accuracy in three top meter style choicesof the system.
18. A proposed classification system for liver metastasis from colorectal carcinoma.
Science.gov (United States)
Petrelli, N J; Bonnheim, D C; Herrera, L O; Mittelman, A
1984-04-01
A proposed classification system for liver metastasis from colorectal carcinoma is presented. This proposed system utilizes the prognostic factors of the extent of hepatic involvement by metastasis at the time of laparotomy, performance status, preoperative serum alkaline phosphatase level, and the presence or absence of extrahepatic intraabdominal disease at the time of laparotomy. Because of the several different modes of treatment for liver metastasis from colorectal carcinoma, it is necessary that a liver classification system be adopted so that different treatment groups will be comparable. The proposed system utilizes the extent of hepatic involvement by metastasis at laparotomy with a division into three subsets of patients described by a Roman numeral. Roman numeral I represents less than or equal to 25 per cent involvement of the liver by metastasis; Roman numeral II represents greater than 25 per cent but less than or equal to 50 per cent involvement by liver metastasis, and Roman numeral III represents greater than 50 per cent involvement by liver metastasis. An Arabic subscript number is used to describe the patients' performance status. Alkaline phosphatase levels are described by a subscript letter with a representing less than two times normal alkaline phosphatase, b representing greater than two times, but less than four times normal levels, and c representing greater than four times normal levels. At the time of laparotomy extrahepatic intra-abdominal disease is represented by the superscript letter E. PMID:6714032
19. Classification of time series patterns from complex dynamic systems
Energy Technology Data Exchange (ETDEWEB)
Schryver, J.C.; Rao, N.
1998-07-01
An increasing availability of high-performance computing and data storage media at decreasing cost is making possible the proliferation of large-scale numerical databases and data warehouses. Numeric warehousing enterprises on the order of hundreds of gigabytes to terabytes are a reality in many fields such as finance, retail sales, process systems monitoring, biomedical monitoring, surveillance and transportation. Large-scale databases are becoming more accessible to larger user communities through the internet, web-based applications and database connectivity. Consequently, most researchers now have access to a variety of massive datasets. This trend will probably only continue to grow over the next several years. Unfortunately, the availability of integrated tools to explore, analyze and understand the data warehoused in these archives is lagging far behind the ability to gain access to the same data. In particular, locating and identifying patterns of interest in numerical time series data is an increasingly important problem for which there are few available techniques. Temporal pattern recognition poses many interesting problems in classification, segmentation, prediction, diagnosis and anomaly detection. This research focuses on the problem of classification or characterization of numerical time series data. Highway vehicles and their drivers are examples of complex dynamic systems (CDS) which are being used by transportation agencies for field testing to generate large-scale time series datasets. Tools for effective analysis of numerical time series in databases generated by highway vehicle systems are not yet available, or have not been adapted to the target problem domain. However, analysis tools from similar domains may be adapted to the problem of classification of numerical time series data.
20. Fault Tolerant Neural Network for ECG Signal Classification Systems
Directory of Open Access Journals (Sweden)
MERAH, M.
2011-08-01
Full Text Available The aim of this paper is to apply a new robust hardware Artificial Neural Network (ANN for ECG classification systems. This ANN includes a penalization criterion which makes the performances in terms of robustness. Specifically, in this method, the ANN weights are normalized using the auto-prune method. Simulations performed on the MIT ? BIH ECG signals, have shown that significant robustness improvements are obtained regarding potential hardware artificial neuron failures. Moreover, we show that the proposed design achieves better generalization performances, compared to the standard back-propagation algorithm.
1. Classification of boundary equilibrium bifurcations in planar Filippov systems.
Science.gov (United States)
Glendinning, Paul
2016-01-01
If a family of piecewise smooth systems depending on a real parameter is defined on two different regions of the plane separated by a switching surface, then a boundary equilibrium bifurcation occurs if a stationary point of one of the systems intersects the switching surface at a critical value of the parameter. We derive the leading order terms of a normal form for boundary equilibrium bifurcations of planar systems. This makes it straightforward to derive a complete classification of the bifurcations that can occur. We are thus able to confirm classic results of Filippov [Differential Equations with Discontinuous Right Hand Sides (Kluwer, Dordrecht, 1988)] using different and more transparent methods, and explain why the 'missing' cases of Hogan et al. [Piecewise Smooth Dynamical Systems: The Case of the Missing Boundary Equilibrium Bifurcations (University of Bristol, 2015)] are the only cases omitted in more recent work.
2. A complete electrical hazard classification system and its application
Energy Technology Data Exchange (ETDEWEB)
Gordon, Lloyd B [Los Alamos National Laboratory; Cartelli, Laura [Los Alamos National Laboratory
2009-01-01
The Standard for Electrical Safety in the Workplace, NFPA 70E, and relevant OSHA electrical safety standards evolved to address the hazards of 60-Hz power that are faced primarily by electricians, linemen, and others performing facility and utility work. This leaves a substantial gap in the management of electrical hazards in Research and Development (R&D) and specialized high voltage and high power equipment. Examples include lasers, accelerators, capacitor banks, electroplating systems, induction and dielectric heating systems, etc. Although all such systems are fed by 50/60 Hz alternating current (ac) power, we find substantial use of direct current (dc) electrical energy, and the use of capacitors, inductors, batteries, and radiofrequency (RF) power. The electrical hazards of these forms of electricity and their systems are different than for 50160 Hz power. Over the past 10 years there has been an effort to develop a method of classifying all of the electrical hazards found in all types of R&D and utilization equipment. Examples of the variation of these hazards from NFPA 70E include (a) high voltage can be harmless, if the available current is sufficiently low, (b) low voltage can be harmful if the available current/power is high, (c) high voltage capacitor hazards are unique and include severe reflex action, affects on the heart, and tissue damage, and (d) arc flash hazard analysis for dc and capacitor systems are not provided in existing standards. This work has led to a comprehensive electrical hazard classification system that is based on various research conducted over the past 100 years, on analysis of such systems in R&D, and on decades of experience. Initially, national electrical safety codes required the qualified worker only to know the source voltage to determine the shock hazard. Later, as arc flash hazards were understood, the fault current and clearing time were needed. These items are still insufficient to fully characterize all types of
3. An Evaluation of ADLs on Modeling Patterns for Software Architecture
NARCIS (Netherlands)
2007-01-01
Architecture patterns provide solutions to recurring design problems at the architecture level. In order to model patterns during software architecture design, one may use a number of existing Architecture Description Languages (ADLs), including the UML, a generic language but also a de facto indust
4. Light-water reactors reference system classification for the European reliability data system (ERDS)
International Nuclear Information System (INIS)
The reference system classification represents a basic stage in the organization of the European reliability data system (ERDS) for light-water reactors, a project actually in development at the Joint Research Centre, Ispra. This project is concerned with operational reliability data collection from the various ''national'' data banks, and centralization in a European reliability data system, so improving the significance of the resulting reliability evaluations. In the framework of the ERDS project, the reference system classification provides a LWR functional break-down and represents a plant-unique identification in the process of homogenization of event-data coming from the various ''national'' organizations. The report, after a brief description of the main objectives of the ERDS project, reviews the criteria followed in the elaboration of the reference system classification; then the detailed classification is presented. The nuclear power station is subdivided in about 180 systems. To each system a sheet is associated, containing: a comprehensive description of system-functions and boundaries; a descritpion of the plant operating mode, linked to the various system functions; a list of the main interface system; and finally, a list of the main components, including type and safety classification
5. Inter-rater reliability of the EPUAP pressure ulcer classification system using photographs.
NARCIS (Netherlands)
Defloor, T.; Schoonhoven, L.
2004-01-01
BACKGROUND: Many classification systems for grading pressure ulcers are discussed in the literature. Correct identification and classification of a pressure ulcer is important for accurate reporting of the magnitude of the problem, and for timely prevention. The reliability of pressure ulcer classif
6. Understanding Acupuncture Based on ZHENG Classification from System Perspective
Directory of Open Access Journals (Sweden)
Junwei Fang
2013-01-01
Full Text Available Acupuncture is an efficient therapy method originated in ancient China, the study of which based on ZHENG classification is a systematic research on understanding its complexity. The system perspective is contributed to understand the essence of phenomena, and, as the coming of the system biology era, broader technology platforms such as omics technologies were established for the objective study of traditional chinese medicine (TCM. Omics technologies could dynamically determine molecular components of various levels, which could achieve a systematic understanding of acupuncture by finding out the relationships of various response parts. After reviewing the literature of acupuncture studied by omics approaches, the following points were found. Firstly, with the help of omics approaches, acupuncture was found to be able to treat diseases by regulating the neuroendocrine immune (NEI network and the change of which could reflect the global effect of acupuncture. Secondly, the global effect of acupuncture could reflect ZHENG information at certain structure and function levels, which might reveal the mechanism of Meridian and Acupoint Specificity. Furthermore, based on comprehensive ZHENG classification, omics researches could help us understand the action characteristics of acupoints and the molecular mechanisms of their synergistic effect.
7. Gender and cultural issues in psychiatric nosological classification systems.
Science.gov (United States)
van de Water, Tanya; Suliman, Sharain; Seedat, Soraya
2016-08-01
Much has changed since the two dominant mental health nosological systems, the International Classification of Diseases (ICD) and the Diagnostic and Statistical Manual of Mental Disorders (DSM), were first published in 1900 and 1952, respectively. Despite numerous modifications to stay up to date with scientific and cultural changes (eg, exclusion of homosexuality as a disorder) and to improve the cultural sensitivity of psychiatric diagnoses, the ICD and DSM have only recently renewed attempts at harmonization. Previous nosological iterations demonstrate the oscillation in the importance placed on the biological focus, highlighting the tension between a gender- and culture-free nosology (solely biological) and a contextually relevant understanding of mental illness. In light of the release of the DSM 5, future nosological systems, such as the ICD 11, scheduled for release in 2017, and the Research Development Criteria (RDoC), can learn from history and apply critiques. This article aims to critically consider gender and culture in previous editions of the ICD and DSM to inform forthcoming classifications. PMID:27133577
8. A data-stream classification system for investigating terrorist threats
Science.gov (United States)
Schulz, Alexia; Dettman, Joshua; Gottschalk, Jeffrey; Kotson, Michael; Vuksani, Era; Yu, Tamara
2016-05-01
The role of cyber forensics in criminal investigations has greatly increased in recent years due to the wealth of data that is collected and available to investigators. Physical forensics has also experienced a data volume and fidelity revolution due to advances in methods for DNA and trace evidence analysis. Key to extracting insight is the ability to correlate across multi-modal data, which depends critically on identifying a touch-point connecting the separate data streams. Separate data sources may be connected because they refer to the same individual, entity or event. In this paper we present a data source classification system tailored to facilitate the investigation of potential terrorist activity. This taxonomy is structured to illuminate the defining characteristics of a particular terrorist effort and designed to guide reporting to decision makers that is complete, concise, and evidence-based. The classification system has been validated and empirically utilized in the forensic analysis of a simulated terrorist activity. Next-generation analysts can use this schema to label and correlate across existing data streams, assess which critical information may be missing from the data, and identify options for collecting additional data streams to fill information gaps.
9. Classification of hospitals based on measured output: the VA system.
Science.gov (United States)
Thomas, J W; Berki, S E; Wyszewianski, L; Ashcraft, M L
1983-07-01
Evaluation of hospital performance and improvement of resource allocation in hospital systems require a method for classifying hospitals on the basis of their output. Previous approaches to hospital classification relied largely on input characteristics. The authors propose and apply a procedure for classifying hospitals into groups where within-group hospitals are similar with respect to output. Direct measures of case-mix-adjusted discharges and outpatient visits are the principal measures of patient care output; other measures capture training and research functions. The component measures were weighted, and a composite output measure was calculated for each of the 162 hospitals in the Veterans Administration health care system. The output score then was used as the dependent variable in an Automatic Interaction Detector analysis, which partitioned the 162 hospitals into 10 groups, accounting for 85 per cent of the variance in the dependent variable. An extension of the output classification method is presented for illustration of how the difference between hospitals' actual operating costs and costs predicted on the basis of output can be used in defining isoefficiency groups. PMID:6350744
10. Tangata whaiora/consumers perspectives on current psychiatric classification systems
Directory of Open Access Journals (Sweden)
Wells Debra
2008-06-01
Full Text Available Abstract Background A number of studies have been undertaken with the aim of considering the utility of mental health classification systems from the perspective of a variety of stakeholders. There is a lack of research on how useful consumers/tangata whaiora think these are in assisting them in their recovery. Methods Seventy service users were involved in seven focus groups in order to consider this question. Results and discussion While for clinicians diagnosing someone might be a discrete event and easily forgotten as a moment in a busy schedule, most people in this study remembered the occasion and aftermath very clearly. The overall consensus was that whether being 'diagnosed' was helpful or not, in large part, depended on how the process happened and what resulted from being 'labeled' in the person's life. Conclusion Overall, people thought that in terms of their recovery, the classification systems were tools and their utility depended on how they were used. They suggested that whatever tool was used it needed to help them make sense of their distress and provide them with a variety of supports, not just medication, to assist them to live lives that were meaningful to them.
11. CLASSIFICATION OF MAMMOGRAPHIC MASSES USING FUZZY INFERENCE SYSTEM
Directory of Open Access Journals (Sweden)
2015-10-01
Full Text Available Computer aided detection (CAD intends to provide assistance to the mammography detection, reducing breast cancer misdiagnosis, thus allowing better diagnosis and more efficient treatments. In this work the task of automatically classifying the mass tissue into Breast Imaging Reporting and Data System (BI-RADS shape categories: round, oval, lobular, irregular and also as benign or malignant is investigated. Geometrical shape and margin features based on maximum and minimum radius of mass are used in this work to classify the masses. These geometric features are found to be good in discriminating regular shapes from irregular shapes. For the purpose of classification, the masses are segmented from the mammogram using gray level thresholding. Finally, the classification is performed using fuzzy inference system. The fuzzy rules are used to construct the generalized fuzzy membership function for classifying the shape and severity of masses. The images were collected from Mammographic Image Analysis Society (MIAS Database and Digital Database for Screening Mammography (DDSM. The experiments were implemented in MATLAB.
12. ATTACHMENTS IN PROSTHODONTICS: DIFFERENT SYSTEMS OF CLASSIFICATION: A REVIEW
Directory of Open Access Journals (Sweden)
Khuthija Khanam
2014-07-01
Full Text Available Attachments are mechanical devices for the fixation and stabilisation of a dental prosthesis and include frictional, internal, intracoronal, extracoronal, key-key way, parallel, precision and slotted types. (Boucher 1976. Attachments are used as alternative to clasps in removable partial denture therapy for both aesthetic and functional purpose. Their application is not only limited to removable partial dentures, but has a broader usage in fixed bridges, overdentures, implant supported dentures as well. Hundreds of attachments are available commercially and significant differences exist between them. In this article, different systems of classification of attachments have been reviewed. They are categorised as precision and semi-precision depending on the method of manufacture, intracoronal and extra coronal depending on their location relative to the abutment tooth, rigid and resilient determined by the amount of movement allowed between the component parts, also as stud and bar attachments depending on the design. A classification system to more accurately evaluate differences among resilient attachments has also been described here.
13. Pathohistological classification systems in gastric cancer: Diagnostic relevance and prognostic value
OpenAIRE
Berlth, Felix; Bollschweiler, Elfriede; Drebber, Uta; Hoelscher, Arnulf H; Moenig, Stefan
2014-01-01
Several pathohistological classification systems exist for the diagnosis of gastric cancer. Many studies have investigated the correlation between the pathohistological characteristics in gastric cancer and patient characteristics, disease specific criteria and overall outcome. It is still controversial as to which classification system imparts the most reliable information, and therefore, the choice of system may vary in clinical routine. In addition to the most common classification systems...
14. Optimal User-Centered Knowledge Organization and Classification Systems: Using Non-reflected Gray Codes
OpenAIRE
Losee, Robert M.
2006-01-01
Existing library classification systems, such as the Dewey Decimal Classification (DDC) system and the Library of Congress Classification system, are generally considered effective at bringing similar documents together. For example, the DDC system is widely used to classify books in libraries and increasingly is being used for online applications, such as browsing Online Public Access Catalogues (OPACs) and Cooperative Online Resource Catalogs (CORCs), and will probably see increasing use in...
15. Operating Rule Classification System of Water Supply Reservoir Based on Learning Classifier System
Institute of Scientific and Technical Information of China (English)
ZHANG Xian-feng; WANG Xiao-lin; YIN Zheng-jie; LI Hui-qiang
2008-01-01
An operating rule classification system based on lesrning classifier system (LCS), which learns through credit assignment (bucket brigade algorithm, BBA) and rule discovery (genetic algorithm, GA), is established to extract water-supply reservoir operating rules. The proposed system acquires an online identification rate of 95% for training samples and an offline rate of 85% for testing samples in a case study. The performances of the rule classification system are discussed from the rationality of the obtained rules, the impact of training samples on rule extraction, and a comparison between the rule classification system and the artificial neural network (ANN). The results indicate that the LCS is feasible and effective for the system to obtain the reservoir supply operating rules.
16. Development Of An Econometric Model Case Study: Romanian Classification System
Directory of Open Access Journals (Sweden)
Savescu Roxana
2015-08-01
Full Text Available The purpose of the paper is to illustrate an econometric model used to predict the lean meat content in pig carcasses, based on the muscle thickness and back fat thickness measured by the means of an optical probe (OptiGrade PRO.The analysis goes through all steps involved in the development of the model: statement of theory, specification of the mathematical model, sampling and collection of data, estimation of the parameters of the chosen econometric model, tests of the hypothesis derived from the model and prediction equations. The data have been in a controlled experiment conducted by the Romanian Carcass Classification Commission in 2007. The purpose of the experiment was to develop the prediction formulae to be used in the implementation of SEUROP classification system, imposed by European Union legislation. The research methodology used by the author in this study consisted in reviewing the existing literature and normative acts, analyzing the primary data provided by and organization conducting the experiment and interviewing the representatives of the working team that participated in the trial.
17. Aneurysms of the superficial venous system: classification and treatment
Directory of Open Access Journals (Sweden)
Ronald G. Bush
2014-11-01
Full Text Available Superficial venous aneurysms are rarely described and they may remain indolent or become the source for pulmonary emboli. A system of classification and treatment protocol according to size and location is proposed. Three hundred thirty patients were evaluated for symptomatic venous disease (C2-C6 over a 2-year period. A proposed designation for venous aneurysm is described. Patients fulfilling this criterion are described in reference to site of involvement, histologic findings, and method of treatment. Five percent of patients met the criteria for venous aneurysm. Nine aneurysms of the greater saphenous vein were identified. Three aneurysms were proximal to the subterminal valve and the rest were distal. Six aneurysms of the anterior accessory greater saphenous vein (AAGSV were identified. Three aneurysms of the AAGSV spontaneously thrombosed. Two patients presented with aneurysms of the small saphenous vein. Histology revealed thickened intima, smooth muscle and adventitia. Aneurysm designation relates to diameter of normal and contiguous vein. All superficial venous aneurysms in close proximity to the junction of the femoral or popliteal vein should be ligated. Classification of venous aneurysms should include the AAGSV, which may present with spontaneous thrombosis.
18. Challenging of Facial Expressions Classification Systems: Survey, Critical Considerations and Direction of Future Work
OpenAIRE
2012-01-01
The main purpose of this study is analysis of the parameters and the affects of those on the performance of the facial expressions classification systems. In recent years understanding of emotions is a basic requirement in the development of Human Computer Interaction (HCI) systems. Therefore, an HCI is highly depended on accurate understanding of facial expression. Classification module is the main part of facial expressions recognition system. Numerous classification techniques were propose...
19. Classification Systems, their Digitization and Consequences for Data-Driven Decision Making
DEFF Research Database (Denmark)
Stein, Mari-Klara; Newell, Sue; Galliers, Robert D.;
2013-01-01
Classification systems are foundational in many standardized software tools. This digitization of classification systems gives them a new ‘materiality’ that, jointly with the social practices of information producers/consumers, has significant consequences on the representational quality of such ...... and the foundational role of representational quality in understanding the success and consequences of data-driven decision-making.......-narration and meta-narration), and three different information production/consumption situations. We contribute to the relational theorization of representational quality and extend classification systems research by drawing explicit attention to the importance of ‘materialization’ of classification systems...
20. From fault classification to fault tolerance for multi-agent systems
CERN Document Server
Potiron, Katia; Taillibert, Patrick
2013-01-01
Faults are a concern for Multi-Agent Systems (MAS) designers, especially if the MAS are built for industrial or military use because there must be some guarantee of dependability. Some fault classification exists for classical systems, and is used to define faults. When dependability is at stake, such fault classification may be used from the beginning of the system's conception to define fault classes and specify which types of faults are expected. Thus, one may want to use fault classification for MAS; however, From Fault Classification to Fault Tolerance for Multi-Agent Systems argues that
1. [Application of ecological classification system in China's digital forestry].
Science.gov (United States)
Tang, Li-Na; Dai, Li-Min
2008-02-01
In China's conventional forest management system, there are two types of sub-compartment, i.e., the 2nd- and 3rd-level sub-compartments, which are concurrent but inconsistent in size and boundary locations. Even in the same type of sub-compartments, the inconsistency still existed at different time, which is unbeneficial to the long-term forest management planning by using digital technologies. With the mountainous region in eastern Liaoning Province as a case, this paper established an ecological classification system (ECS), which contained 5 ecological land types (ELTs) and 34 ecological land type phases (ELTPs). Based on the basic technical needs of China's digital forestry, the ELTPs could be used as a fixed sub-compartment system. A compatible forest inventory system was designed then. It was concluded that ecosystem management based on ECS and geospatial information technologies combined with computer models and decision-support systems would be the important component of digital forestry. PMID:18464630
2. The Self-Directed Violence Classification System and the Columbia Classification Algorithm for Suicide Assessment: A Crosswalk
Science.gov (United States)
Matarazzo, Bridget B.; Clemans, Tracy A.; Silverman, Morton M.; Brenner, Lisa A.
2013-01-01
The lack of a standardized nomenclature for suicide-related thoughts and behaviors prompted the Centers for Disease Control and Prevention, with the Veterans Integrated Service Network 19 Mental Illness Research Education and Clinical Center, to create the Self-Directed Violence Classification System (SDVCS). SDVCS has been adopted by the…
3. Human posture classification for intelligent visual surveillance systems
Science.gov (United States)
Rababaah, Haroun; Shirkhodaie, Amir
2008-04-01
Intelligent surveillance systems (ISS) have gained a significant attention in recent years due to the nationwide security concerns. Some of the important applications of ISS include: homeland security, border monitoring, battlefield intelligence, and sensitive facility monitoring. The essential requirements of an ISS include: (1) multi-modality multi-sensor data and information fusion, (2) communication networking, (3) distributed data/information processing,(4) Automatic target recognition and tracking, (5) Scenario profiling from discrete correlated/uncorrelated events, (6) Context-based situation reasoning, and (7) Collaborative resource sharing and decision support systems. In this paper we have addressed the problem of humanposture classification in crowded urban terrain environments. Certain range of human postures can be attributed to different suspicious acts of intruders in a constrained environment. By proper time analysis of human trespassers' postures in an environment, it would be possible to identify and differentiate malicious intention of the trespassers from other normal human behaviors. Specifically in this paper, we have proposed an image processing-based approach for characterization of five different human postures including: standing, bending, crawling, carrying a heavy object, and holding a long object. Two approaches were introduced to address the problem: template-matching and Hamming Adaptive Neural Network (HANN) classifiers. The former approach performs human posture characterization via binary-profile projection and applies a correlation-based method for classification of human postures. The latter approach is based a HANN technique. For training of the neural, the posture-patterns are initially compressed, thresholded, and serialized. The binary posture-pattern arrays were then used for training of the HANN. The comparative performance evaluation of both approaches the same set of training and testing examples were used to measure
4. 42 CFR 419.31 - Ambulatory payment classification (APC) system and payment weights.
Science.gov (United States)
2010-10-01
... 42 Public Health 3 2010-10-01 2010-10-01 false Ambulatory payment classification (APC) system and... Outpatient Services § 419.31 Ambulatory payment classification (APC) system and payment weights. (a) APC... OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEM FOR...
5. Classification systems in nursing : Formalizing nursing knowledge and implications for nursing information systems
NARCIS (Netherlands)
Goossen, WTF; Epping, PJMM; Abraham, IL
1996-01-01
The development of nursing information systems (NIS) is often hampered by the fact that nursing lacks a unified nursing terminology and classification system. Currently there exist various initiatives in this area. We address the question as to how current initiatives in the development of nursing t
6. Risk classification and uncertainty propagation for virtual water distribution systems
International Nuclear Information System (INIS)
While the secrecy of real water distribution system data is crucial, it poses difficulty for research as results cannot be publicized. This data includes topological layouts of pipe networks, pump operation schedules, and water demands. Therefore, a library of virtual water distribution systems can be an important research tool for comparative development of analytical methods. A virtual city, 'Micropolis', has been developed, including a comprehensive water distribution system, as a first entry into such a library. This virtual city of 5000 residents is fully described in both geographic information systems (GIS) and EPANet hydraulic model frameworks. A risk classification scheme and Monte Carlo analysis are employed for an attempted water supply contamination attack. Model inputs to be considered include uncertainties in: daily water demand, seasonal demand, initial storage tank levels, the time of day a contamination event is initiated, duration of contamination event, and contaminant quantity. Findings show that reasonable uncertainties in model inputs produce high variability in exposure levels. It is also shown that exposure level distributions experience noticeable sensitivities to population clusters within the contaminant spread area. High uncertainties in exposure patterns lead to greater resources needed for more effective mitigation strategies.
7. The tool in the brain: Apraxia in ADL.
Directory of Open Access Journals (Sweden)
Marta M. N. Bienkiewicz
2014-04-01
Full Text Available Humans differ from other animals in the way they can skilfully and precisely operate or invent tools to facilitate their everyday life. Tools have dominated our home, travel and work environment, becoming an integral step for our motor skills development. What happens when the part of the brain responsible for tool use is damaged in our adult life due to a cerebrovascular accident? How does daily life change when we lose the previously mastered ability to make use of the objects around us? How do patients suffering from compromised tool use cope with food preparation, personal hygiene, grooming, housework or use of home appliances? In this literature review we present a state of the art for single and multiple tool use research, with a focus on the impact that apraxia (impaired ability to perform tool-based actions and action disorganisation syndrome (impaired ability to carry our multi-step actions have on activities of daily living (ADL. Firstly, we summarise the behavioural studies investigating the impact of apraxia and other comorbidity syndromes, such as neglect or visual extinction, on ADL. We discuss the hallmarks of the compromised tool use in terms of the sequencing of action steps, conceptual errors committed, spatial motor control and temporal organisation of the movement. In addition, we present an up-to-date overview of the neuroimaging and lesion analyses studies that provide an insight into neural correlates of tool use in the human brain and functional changes in the neural organisation following a stroke, in the context of ADL. Finally we discuss the current practice in neurorehabilitation of ADL in apraxia and action disorganisation syndrome aiming at increasing patients’ independence.
8. Classification of multipartite systems featuring only $|W\\rangle$ and $|GHZ\\rangle$ genuine entangled states
OpenAIRE
Holweck, Frédéric; Lévay, Péter
2015-01-01
In this paper we present several multipartite quantum systems featuring the same type of genuine (tripartite) entanglement. Based on a geometric interpretation of the so-called $|W\\rangle$ and $|GHZ\\rangle$ states we show that the classification of all multipartite systems featuring those and only those two classes of genuine entanglement can be deduced from earlier work of algebraic geometers. This classification corresponds in fact to classification of fundamental subadjoint varieties and e...
9. Multivariate classification of systemic vascular resistance using photoplethysmography
International Nuclear Information System (INIS)
Systemic vascular resistance (SVR) classification is useful for the diagnosis and prognosis of critical pathophysiological conditions, with the ability to identify patients with abnormally high or low SVR of immense clinical value. In this study, a supervised classifier, based on Bayes' rule, is employed to classify a heterogeneous group of intensive care unit patients (N = 48) as being below (SVR < 900 dyn s cm−5), within (900 ≤ SVR ≤ 1200 dyn s cm−5) or above (SVR > 1200 dyn s cm−5) the clinically accepted range for normal SVR. Features derived from the finger photoplethysmogram (PPG) waveform and other routine cardiovascular measurements (heart rate and mean arterial pressure) were used as inputs to the classifier. In the construction of the classifier model, two techniques were used to approximate the class conditional probability densities-–a single Gaussian distribution model (also known as discriminant analysis) and a non-parametric model using the Parzen window kernel density estimation method. An exhaustive feature search was performed to select a feature subset that maximized the performance indicator, Cohen's kappa coefficient (κ). The Gaussian model with multiple features achieved the best overall kappa coefficient (κ = 0.57), although the results from the non-parametric model were comparable (κ = 0.51). The optimum subset in the Gaussian model consisted of PPG waveform variability features, including the low-frequency to high-frequency ratio (LF/HF) and the normalized mid-frequency power (MFNU), in addition to the PPG pulse wave features, such as pulse width, peak-to-notch time, reflection index, and notch time ratio. The classifier performed particularly well in discriminating low SVR, with a sensitivity of 85%, specificity of 86%, positive predictive value of 88% and a negative predictive value of 82%. The results highlight the feasibility of deploying a multivariate statistical approach of SVR classification in the clinical
10. Transporter Classification Database (TCDB)
Data.gov (United States)
U.S. Department of Health & Human Services — The Transporter Classification Database details a comprehensive classification system for membrane transport proteins known as the Transporter Classification (TC)...
11. Superiority of Classification Tree versus Cluster, Fuzzy and Discriminant Models in a Heartbeat Classification System
Science.gov (United States)
Krasteva, Vessela; Jekova, Irena; Leber, Remo; Schmid, Ramun; Abächerli, Roger
2015-01-01
This study presents a 2-stage heartbeat classifier of supraventricular (SVB) and ventricular (VB) beats. Stage 1 makes computationally-efficient classification of SVB-beats, using simple correlation threshold criterion for finding close match with a predominant normal (reference) beat template. The non-matched beats are next subjected to measurement of 20 basic features, tracking the beat and reference template morphology and RR-variability for subsequent refined classification in SVB or VB-class by Stage 2. Four linear classifiers are compared: cluster, fuzzy, linear discriminant analysis (LDA) and classification tree (CT), all subjected to iterative training for selection of the optimal feature space among extended 210-sized set, embodying interactive second-order effects between 20 independent features. The optimization process minimizes at equal weight the false positives in SVB-class and false negatives in VB-class. The training with European ST-T, AHA, MIT-BIH Supraventricular Arrhythmia databases found the best performance settings of all classification models: Cluster (30 features), Fuzzy (72 features), LDA (142 coefficients), CT (221 decision nodes) with top-3 best scored features: normalized current RR-interval, higher/lower frequency content ratio, beat-to-template correlation. Unbiased test-validation with MIT-BIH Arrhythmia database rates the classifiers in descending order of their specificity for SVB-class: CT (99.9%), LDA (99.6%), Cluster (99.5%), Fuzzy (99.4%); sensitivity for ventricular ectopic beats as part from VB-class (commonly reported in published beat-classification studies): CT (96.7%), Fuzzy (94.4%), LDA (94.2%), Cluster (92.4%); positive predictivity: CT (99.2%), Cluster (93.6%), LDA (93.0%), Fuzzy (92.4%). CT has superior accuracy by 0.3–6.8% points, with the advantage for easy model complexity configuration by pruning the tree consisted of easy interpretable ‘if-then’ rules. PMID:26461492
12. An overview of some historical knowledge organisation systems and classifications with a special emphasy on monastery libraries’ classification
Directory of Open Access Journals (Sweden)
Sonja Svoljšak
2005-01-01
Full Text Available The article gives an overview of some most prominent historical turning – points in the field of knowledge organization an2d western European sistematization of science, based on Greek and christian philosophy. Some examples of earlier attempts to unify the systems of knowledge organization and science systematization are presented. Some specific systems of the most prominent European christian religious orders’ library contents arrangement and classification are described in this context.
13. Asynchronous data-driven classification of weapon systems
International Nuclear Information System (INIS)
This communication addresses real-time weapon classification by analysis of asynchronous acoustic data, collected from microphones on a sensor network. The weapon classification algorithm consists of two parts: (i) feature extraction from time-series data using symbolic dynamic filtering (SDF), and (ii) pattern classification based on the extracted features using the language measure (LM) and support vector machine (SVM). The proposed algorithm has been tested on field data, generated by firing of two types of rifles. The results of analysis demonstrate high accuracy and fast execution of the pattern classification algorithm with low memory requirements. Potential applications include simultaneous shooter localization and weapon classification with soldier-wearable networked sensors. (rapid communication)
14. Using IPEDS To Develop a Classification System for Two-Year Postsecondary Institutions.
Science.gov (United States)
Merisotis, Jamie P.; Shedd, Jessica M.
2003-01-01
Explores the development of a classification system for two-year institutions that can provide a framework for analysis and contribute to the discourse in public policy. The proposed classification system is based on cluster analyses using data from the National Center for Education Statistics' Integrated Postsecondary Education Data System…
15. Perceptual and Acoustic Reliability Estimates for the Speech Disorders Classification System (SDCS)
Science.gov (United States)
Shriberg, Lawrence D.; Fourakis, Marios; Hall, Sheryl D.; Karlsson, Heather B.; Lohmeier, Heather L.; McSweeny, Jane L.; Potter, Nancy L.; Scheer-Cohen, Alison R.; Strand, Edythe A.; Tilkens, Christie M.; Wilson, David L.
2010-01-01
A companion paper describes three extensions to a classification system for paediatric speech sound disorders termed the Speech Disorders Classification System (SDCS). The SDCS uses perceptual and acoustic data reduction methods to obtain information on a speaker's speech, prosody, and voice. The present paper provides reliability estimates for…
16. Volunteer-Based System for classification of traffic in computer networks
DEFF Research Database (Denmark)
Bujlow, Tomasz; Balachandran, Kartheepan; Riaz, M. Tahir;
2011-01-01
To overcome the drawbacks of existing methods for traffic classification (by ports, Deep Packet Inspection, statistical classification) a new system was developed, in which the data are collected from client machines. This paper presents design of the system, implementation, initial runs and obta...
17. Application of the Safety Classification of Structures, Systems and Components in Nuclear Power Plants
International Nuclear Information System (INIS)
This publication describes how to complete tasks associated with every step of the classification methodology set out in IAEA Safety Standards Series No. SSG-30, Safety Classification of Structures, Systems and Components in Nuclear Power Plants. In particular, how to capture all the structures, systems and components (SSCs) of a nuclear power plant to be safety classified. Emphasis is placed on the SSCs that are necessary to limit radiological releases to the public and occupational doses to workers in operational conditions This publication provides information for organizations establishing a comprehensive safety classification of SSCs compliant with IAEA recommendations, and to support regulators in reviewing safety classification submitted by licensees
18. Standard practice for verification and classification of extensometer systems
CERN Document Server
American Society for Testing and Materials. Philadelphia
2010-01-01
1.1 This practice covers procedures for the verification and classification of extensometer systems, but it is not intended to be a complete purchase specification. The practice is applicable only to instruments that indicate or record values that are proportional to changes in length corresponding to either tensile or compressive strain. Extensometer systems are classified on the basis of the magnitude of their errors. 1.2 Because strain is a dimensionless quantity, this document can be used for extensometers based on either SI or US customary units of displacement. Note 1—Bonded resistance strain gauges directly bonded to a specimen cannot be calibrated or verified with the apparatus described in this practice for the verification of extensometers having definite gauge points. (See procedures as described in Test Methods E251.) 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish app...
19. Comparison of wheat classification accuracy using different classifiers of the image-100 system
Science.gov (United States)
Dejesusparada, N. (Principal Investigator); Chen, S. C.; Moreira, M. A.; Delima, A. M.
1981-01-01
Classification results using single-cell and multi-cell signature acquisition options, a point-by-point Gaussian maximum-likelihood classifier, and K-means clustering of the Image-100 system are presented. Conclusions reached are that: a better indication of correct classification can be provided by using a test area which contains various cover types of the study area; classification accuracy should be evaluated considering both the percentages of correct classification and error of commission; supervised classification approaches are better than K-means clustering; Gaussian distribution maximum likelihood classifier is better than Single-cell and Multi-cell Signature Acquisition Options of the Image-100 system; and in order to obtain a high classification accuracy in a large and heterogeneous crop area, using Gaussian maximum-likelihood classifier, homogeneous spectral subclasses of the study crop should be created to derive training statistics.
20. Lie Group Classification of a Generalized Lane-Emden Type System in Two Dimensions
Directory of Open Access Journals (Sweden)
Motlatsi Molati
2012-01-01
Full Text Available The aim of this work is to perform a complete Lie symmetry classification of a generalized Lane-Emden type system in two dimensions which models many physical phenomena in biological and physical sciences. The classical approach of group classification is employed for classification. We show that several cases arise in classifying the arbitrary parameters, the forms of which include amongst others the power law nonlinearity, and exponential and quadratic forms.
1. Analysis on Design of Kohonen-network System Based on Classification of Complex Signals
Institute of Scientific and Technical Information of China (English)
2002-01-01
The key methods of detection and classification of the electroencephalogram(EEG) used in recent years are introduced . Taking EEG for example, the design plan of Kohonen neural network system based on detection and classification of complex signals is proposed, and both the network design and signal processing are analyzed, including pre-processing of signals, extraction of signal features, classification of signal and network topology, etc.
2. An automated, real time classification system for biological and anthropogenic sounds from fixed ocean observatories
OpenAIRE
Zaugg, Serge Alain; Schaar, Mike van der; Houegnigan, Ludwig; André, Michel
2010-01-01
The automated, real time classification of acoustic events in the marine environment is an important tool to study anthropogenic sound pollution, marine mammals and for mitigating human activities that are potentially harmful. We present a real time classification system targeted at many important groups of acoustic events (clicks, buzzes, calls, whistles from several cetacean species, tonal and impulsive shipping noise and explosions). The achieved classification performance ...
3. Application of Group Analysis to Classification of Systems of Three Second-Order Ordinary Differential Equations
OpenAIRE
Suksern, S.; S. Moyo; Meleshko, S. V.
2013-01-01
Here we give a complete group classification of the general case of linear systems of three second-order ordinary differential equations excluding the case of systems which are studied in the literature. This is given as the initial step in the study of nonlinear systems of three second-order ordinary differential equations. In addition the complete group classification of a system of three linear second-order ordinary differential equations is done. Four cases of linear systems of equations ...
4. Automated cloud classification with a fuzzy logic expert system
Science.gov (United States)
Tovinkere, Vasanth; Baum, Bryan A.
1993-01-01
An unresolved problem in current cloud retrieval algorithms concerns the analysis of scenes containing overlapping cloud layers. Cloud parameterizations are very important both in global climate models and in studies of the Earth's radiation budget. Most cloud retrieval schemes, such as the bispectral method used by the International Satellite Cloud Climatology Project (ISCCP), have no way of determining whether overlapping cloud layers exist in any group of satellite pixels. One promising method uses fuzzy logic to determine whether mixed cloud and/or surface types exist within a group of pixels, such as cirrus, land, and water, or cirrus and stratus. When two or more class types are present, fuzzy logic uses membership values to assign the group of pixels partially to the different class types. The strength of fuzzy logic lies in its ability to work with patterns that may include more than one class, facilitating greater information extraction from satellite radiometric data. The development of the fuzzy logic rule-based expert system involves training the fuzzy classifier with spectral and textural features calculated from accurately labeled 32x32 regions of Advanced Very High Resolution Radiometer (AVHRR) 1.1-km data. The spectral data consists of AVHRR channels 1 (0.55-0.68 mu m), 2 (0.725-1.1 mu m), 3 (3.55-3.93 mu m), 4 (10.5-11.5 mu m), and 5 (11.5-12.5 mu m), which include visible, near-infrared, and infrared window regions. The textural features are based on the gray level difference vector (GLDV) method. A sophisticated new interactive visual image Classification System (IVICS) is used to label samples chosen from scenes collected during the FIRE IFO II. The training samples are chosen from predefined classes, chosen to be ocean, land, unbroken stratiform, broken stratiform, and cirrus. The November 28, 1991 NOAA overpasses contain complex multilevel cloud situations ideal for training and validating the fuzzy logic expert system.
5. Toward a common classification approach for biorefinery systems
NARCIS (Netherlands)
Cherubini, F.; Jungmeier, G.; Wellisch, M.; Wilke, T.; Skiadas, I.; Ree, van R.; Jong, de E.
2009-01-01
This paper deals with a biorefinery classification approach developed within International Energy Agency (IEA) Bioenergy Task 42. Since production of transportation biofuels is seen as the driving force for future biorefinery developments, a selection of the most interesting transportation biofuels
6. Development of the Construction Classification System in Japan (JCCS)
Institute of Scientific and Technical Information of China (English)
Tatsuo Terai
2008-01-01
This paper deals with the intermediate results of the development of a national standardized clas-sification system called JCCS to ensure harmonized use of various kinds of information to be processed through the whole life cycle of construction projects in a nation-wide Japanese CALS/EC scheme. JCCS is planned to be a Japanese IFD and developped on the technical basis of ISO 12006-2 and 12006-3. Japan has currently no such an IFD-like library of terminologies which is to be an essential tool for the multiple and harmonized information processing, so that JCCS should be a key technology for the successful CALS/EC.First, the development concepts and related technologies are described. Second, evaluation of the current situation of information process in the construction industry is clarified, and followed by the requirements of the development of JCCS. In the main part, the current version of JCCS is outlined, major contents of which are the basic architecture of JCCS, JCCS schema, JCCS basic tables and the usage of JCCS in practice.Finally, future develoment in plan is briefly explained.
7. Biopharmaceutics classification system: importance and inclusion in biowaiver guidance
Directory of Open Access Journals (Sweden)
Lorena Barbosa Arrunátegui
2015-03-01
Full Text Available Pharmacological therapy is essential in many diseases treatment and it is important that the medicine policy is intended to offering safe and effective treatment with affordable price to the population. One way to achieve this is through biowaiver, defined as the replacement of in vivo bioequivalence studies by in vitro studies. For biowaiver of new immediate release solid oral dosage forms, data such as intestinal permeability and solubility of the drug are required, as well as the product dissolution. The Biopharmaceutics Classification System (BCS is a scientific scheme that divides drugs according to their solubility and permeability and has been used by various guides as a criterion for biowaiver. This paper evaluates biowaiver application, addressing the general concepts and parameters used by BCS, making a historical account of its use, the requirements pertaining to the current legislation, the benefits and risks associated with this decision. The results revealed that the use of BCS as a biowaiver criterion greatly expands the therapeutics options, contributing to greater therapy access of the general population with drug efficacy and safety guaranteed associated to low cost.
8. A novel classification system for evolutionary aging theories.
Science.gov (United States)
Trindade, Lucas S; Aigaki, Toshiro; Peixoto, Alexandre A; Balduino, Alex; Mânica da Cruz, Ivana B; Heddle, Jonathan G
2013-01-01
Theories of lifespan evolution are a source of confusion amongst aging researchers. After a century of aging research the dispute over whether the aging process is active or passive persists and a comprehensive and universally accepted theoretical model remains elusive. Evolutionary aging theories primarily dispute whether the aging process is exclusively adapted to favor the kin or exclusively non-adapted to favor the individual. Interestingly, contradictory data and theories supporting both exclusively programmed and exclusively non-programmed theories continue to grow. However, this is a false dichotomy; natural selection favors traits resulting in efficient reproduction whether they benefit the individual or the kin. Thus, to understand the evolution of aging, first we must understand the environment-dependent balance between the advantages and disadvantages of extended lifespan in the process of spreading genes. As described by distinct theories, different niches and environmental conditions confer on extended lifespan a range of fitness values varying from highly beneficial to highly detrimental. Here, we considered the range of fitness values for extended lifespan and develop a fitness-based framework for categorizing existing theories. We show that all theories can be classified into four basic types: secondary (beneficial), maladaptive (neutral), assisted death (detrimental), and senemorphic aging (varying between beneficial to detrimental). We anticipate that this classification system will assist with understanding and interpreting aging/death by providing a way of considering theories as members of one of these classes rather than consideration of their individual details.
9. In vitro -in vivo correlation and biopharmaceutical classification system
Directory of Open Access Journals (Sweden)
R Tiwari
2011-01-01
Full Text Available In vitro dissolution has been extensively used as a quality control tool for solid oral dosage forms. In several cases, however, it is not known whether one can predict the in vivo performance of these products from in vitro dissolution data. In an effort to minimize unnecessary human testing, investigations of in vitro-in vivo correlations (IVIVC between in vitro dissolution and in vivo bioavailability are increasingly becoming an integral part of extended release drug product development. Development, rapidity in drug development can be achieved by researchers on finding a mathematical link between bioavailability and dissolution testing, which leads to the concept of IVIVC. IVIVC is a mathematical model that can be used to estimate in vivo behavior from its in vitro performance. Among all the five levels of correlation, Level A correlation is widely accepted by the regulatory agencies. Biopharmaceutical classification system explains the suitability of IVIVC. Dissolution method design plays a pivotal role in the estimation of correlations. Applications of IVIVC ranges from drug and product development, their scale up and postapproval changes. Hence, IVIVC should be considered as an important tool in drug development.
10. The psychometric properties of ADCS - activities of daily living inventory and comparison of different ADL scores
OpenAIRE
Rózsa, S.; Brandtmüller, A.; Nagy, B.; Brennan, A.(School of Physics, University of Melbourne, Victoria, Australia); Akehurst, R
2009-01-01
Several multi-item activities of daily living (ADL) scales have been developed for assessment of functional status of patients with Alzheimer’s Disease (AD) in the last few decades. A disadvantage of the large number of scales is that scores of different ADL scales cannot be compared directly with each other. ADL scales which are used by McNamee’s (Townsend's disability scale) and Hill’s (Medicare Beneficiary definitions and Katz index of ADL) provide suitable tools for modelling the cost-eff...
11. Clinical usefulness of the Vaughan Williams classification system.
Science.gov (United States)
Cobbe, S M
1987-03-01
The clinical usefulness of the Vaughan Williams classification scheme is limited by the complexity of the mechanisms of arrhythmia formation in man, which offer multiple potential sites for intervention. The properties of antiarrhythmic drugs may be considerably altered in abnormal myocardium. Despite these limitations, however, the classification provides a valuable conceptual framework for the understanding of the clinical electrophysiological properties of antiarrhythmic drugs and for their use.
12. Hazard Classification of Household Chemical Products in Korea according to the Globally Harmonized System of Classification and labeling of Chemicals
OpenAIRE
Kim, Kyung-Hee; Song, Dae-Jong; Yu, Myeong-Hyun; Park, Yuon-Shin; Noh, Hye-Ran; Kim, Hae-Joon; Choi, Jae-Wook
2013-01-01
Objectives This study was conducted to review the validity of the need for the application of the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) to household chemical products in Korea. The study also aimed to assess the severity of health and environmental hazards of household chemical products using the GHS. Methods 135 products were classified as ‘cleaning agents and polishing agents’ and 98 products were classified as ‘bleaches, disinfectants, and germicides....
13. Topological, smooth and holomorphic classifications of nonautonomous linear differential systems and projective matrix Riccati equations
CERN Document Server
Gorbuzov, V N
2011-01-01
The questions of global topological, smooth and holomorphic classifications of the differential systems, defined by covering foliations, are considered. The received results are applied to nonautonomous linear differential systems and projective matrix Riccati equations.
14. Invariant Classification and Limits of Maximally Superintegrable Systems in 3D
OpenAIRE
Capel, Joshua J.; Kress, Jonathan M.; Post, Sarah
2015-01-01
The invariant classification of superintegrable systems is reviewed and utilized to construct singular limits between the systems. It is shown, by construction, that all superintegrable systems on conformally flat, 3D complex Riemannian manifolds can be obtained from singular limits of a generic system on the sphere. By using the invariant classification, the limits are geometrically motivated in terms of transformations of roots of the classifying polynomials.
15. Initial steps towards an evidence-based classification system for golfers with a physical impairment
NARCIS (Netherlands)
Stoter, Inge K; Hettinga, Florentina J; Altmann, Viola; Eisma, Wim; Arendzen, Hans; Bennett, Tony; van der Woude, Lucas H; Dekker, Rienk
2015-01-01
PURPOSE: The present narrative review aims to make a first step towards an evidence-based classification system in handigolf following the International Paralympic Committee (IPC). It intends to create a conceptual framework of classification for handigolf and an agenda for future research. METHOD:
16. 15 CFR 921.3 - National Estuarine Research Reserve System biogeographic classification scheme and estuarine...
Science.gov (United States)
2010-01-01
... biogeographic classification scheme and estuarine typologies. (a) National Estuarine Research Reserves are... biogeographic classification scheme is used to ensure that the National Estuarine Research Reserve System... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false National Estuarine Research...
17. Characterization of Neisseria gonorrhoeae reference strains used in development of serologic classification systems.
OpenAIRE
Evins, G. M.; Knapp, J S
1988-01-01
Certain strains of Neisseria gonorrhoeae have been used by numerous investigators to develop serologic classification systems. Some of these strains have been used by investigators to study gonococcal virulence. A reference consisting of strain classification by auxotype and serovar, a strain history, and a selected bibliography are provided cohesively.
18. Using hydrogeomorphic criteria to classify wetlands on Mt. Desert Island, Maine - approach, classification system, and examples
Science.gov (United States)
Nielsen, Martha G.; Guntenspergen, Glenn R.; Neckles, Hilary A.
2005-01-01
A wetland classification system was designed for Mt. Desert Island, Maine, to help categorize the large number of wetlands (over 1,200 mapped units) as an aid to understanding their hydrologic functions. The classification system, developed by the U.S. Geological Survey (USGS), in cooperation with the National Park Service, uses a modified hydrogeomorphic (HGM) approach, and assigns categories based on position in the landscape, soils and surficial geologic setting, and source of water. A dichotomous key was developed to determine a preliminary HGM classification of wetlands on the island. This key is designed for use with USGS topographic maps and 1:24,000 geographic information system (GIS) coverages as an aid to the classification, but may also be used with field data. Hydrologic data collected from a wetland monitoring study were used to determine whether the preliminary classification of individual wetlands using the HGM approach yielded classes that were consistent with actual hydroperiod data. Preliminary HGM classifications of the 20 wetlands in the monitoring study were consistent with the field hydroperiod data. The modified HGM classification approach appears robust, although the method apparently works somewhat better with undisturbed wetlands than with disturbed wetlands. This wetland classification system could be applied to other hydrogeologically similar areas of northern New England.
19. Improvements to the current classification of salary expenses in the accounting system of the enterprise
Directory of Open Access Journals (Sweden)
Fylypenko Anna
2016-04-01
Full Text Available The article considers the existing classification of salary expenses in Ukraine. The analysis of the classifications of such costs in management and accounting is carried out. The article suggests approaches for improvement in the cost-accounting system for the respective enterprise features, which greatly facilitates the management of salary expenses and allows the search of reserves to reduce them.
20. An indigenous soil classification system for Bellona Island - a raised atoll in the Solomon Islands
DEFF Research Database (Denmark)
Elberling, Bo; Breuning-Madsen, Henrik; Bruun, Thilde Bech
2010-01-01
on the island. The Bellonese soil classification system is mainly based on the physical properties of the humus-containing top layer. Subsoil layers are only used for classification if they are very close to the surface and may be mixed with the topsoil. Results show a general agreement among farmers, who...
1. Audio Development Laboratory (ADL) User Test Planning Guide
Science.gov (United States)
Romero, Andy
2012-01-01
Test process, milestones and inputs are unknowns to first-time users of the ADL. The User Test Planning Guide aids in establishing expectations for both NASA and non-NASA facility customers. The potential audience for this guide includes both internal and commercial spaceflight hardware/software developers. It is intended to assist their test engineering personnel in test planning and execution. Material covered includes a roadmap of the test process, roles and responsibilities of facility and user, major milestones, facility capabilities, and inputs required by the facility. Samples of deliverables, test article interfaces, and inputs necessary to define test scope, cost, and schedule are included as an appendix to the guide.
2. Classification of nutrient emission sources in the Vistula River system
International Nuclear Information System (INIS)
Eutrophication of the Baltic sea still remains one of the biggest problems in the north-eastern area of Europe. Recognizing the sources of nutrient emission, classification of their importance and finding the way towards reduction of pollution are the most important tasks for scientists researching this area. This article presents the chemometric approach to the classification of nutrient emission with respect to the regionalisation of emission sources within the Vistula River basin (Poland). Modelled data for mean yearly emission of nitrogen and phosphorus in 1991-2000 has been used for the classification. Seventeen subcatchements in the Vistula basin have been classified according to cluster and factor analyses. The results of this analysis allowed determination of groups of areas with similar pollution characteristics and indicate the need for spatial differentiation of policies and strategies. Three major factors indicating urban, erosion and agricultural sources have been identified as major discriminants of the groups. - Two classification methods applied to evaluate the results of nutrient emission allow definition of major sources of the emissions and classification of catchments with similar pollution.
3. 關於圖書分類法的修訂 Concerning the Revision of Classification System
OpenAIRE
Ho-chin Chen
1999-01-01
無For reviewing a classification scheme, we usually look in much detail at its traditional features such as detailed schedules, hospital notation, a supportive index and its adaptability. Yet another desirable feature, a good and financially secure revision programme, is a key point to the success of classification scheme. The author traces the history of revision processes of three successful classification systems (Dewey Decimal Classification, Library of Congress Classification and Universa...
4. STANSORT - Stanford Remote Sensing Laboratory pattern recognition and classification system
Science.gov (United States)
Honey, F. R.; Prelat, A.; Lyon, R. J. P.
1974-01-01
The principal barrier to routine use of the ERTS multispectral scanner computer compatible tapes, rather than photointerpretation examination of the images, has been the high computing costs involved due to the large quantity of information (4 Mbytes) contained in a scene. STANSORT, the interactive program package developed at Stanford Remote Sensing Laboratories alleviates this problem, providing an extremely rapid, flexible and low cost tool for data reduction, scene classification, species searches and edge detection. The primary classification procedure, utilizing a search with variable gate widths, for similarities in the normalized, digitized spectra is described along with associated procedures for data refinement and extraction of information. The more rigorous statistical classification procedures are also explained.
5. Classification of systems for passive afterheat removal from reactor containment of nuclear power plant with water-cooled power reactor
OpenAIRE
Khaled, N.; D. V. Shevelev; A. S. Balashevsky
2014-01-01
A classification on systems for passive afterheat removal from reactor containment has been developed in the paper. The classification permits to make a detailed analysis of various concepts pertaining to systems for passive afterheat removal from reactor containment of new generation. The paper considers main classification features of the given systems.
6. CLASSIFICATION OF SYSTEMS FOR PASSIVE AFTERHEAT REMOVAL FROM REACTOR CONTAINMENT OF NUCLEAR POWER PLANT WITH WATER-COOLED POWER REACTOR
Directory of Open Access Journals (Sweden)
N. Khaled
2014-01-01
Full Text Available A classification on systems for passive afterheat removal from reactor containment has been developed in the paper. The classification permits to make a detailed analysis of various concepts pertaining to systems for passive afterheat removal from reactor containment of new generation. The paper considers main classification features of the given systems.
7. Injuries from Intimate Partner and Sexual Violence: Significance and Classification Systems
OpenAIRE
Sommers, Marilyn S.; Brunner, Lillian S.; Brown, Kathleen M.; Buschur, Carole; Everett, Janine S.; Fargo, Jamison D.; Fisher, Bonnie S.; Hinkle, Christina; Zink, Therese M
2012-01-01
While intimate partner violence (IPV) and sexual violence (SV) are highly associated with injury, the healthcare and legal significance of these injuries is controversial. Purpose: Herein we propose to explore the significance of injury in IPV and SV and examine the current status of injury classification systems from the perspectives of the healthcare and criminal justice systems. We will review current injury classification systems and suggest a typology of injury that could be tested empir...
8. Medical diagnosis of cardiovascular diseases using an interval-valued fuzzy rule-based classification system
OpenAIRE
Sanz Delgado, José Antonio; Galar Idoate, Mikel; Jurío Munárriz, Aránzazu; Brugos Larumbe, Antonio; Pagola Barrio, Miguel; Bustince Sola, Humberto
2013-01-01
Objective: To develop a classifier that tackles the problem of determining the risk of a patient of suffering from a cardiovascular disease within the next ten years. The system has to provide both a diagnosis and an interpretable model explaining the decision. In this way, doctors are able to analyse the usefulness of the information given by the system. Methods: Linguistic fuzzy rule-based classification systems are used, since they provide a good classification rate and a highly interpreta...
9. Toward a common classification approach for biorefinery systems
DEFF Research Database (Denmark)
Cherubini, Francesco; Jungmeier, Gerfried; Wellisch, Maria;
2009-01-01
until 2020 is based on their characteristics to be mixed with gasoline, diesel and natural gas, reflecting the main advantage of using the already-existing infrastructure for easier market introduction. This classification approach relies on four main features: (1) platforms; (2) products; (3) feedstock......This paper deals with a biorefinery classification approach developed within International Energy Agency (IEA) Bioenergy Task 42. Since production of transportation biofuels is seen as the driving force for future biorefinery developments, a selection of the most interesting transportation biofuels...
10. The evolution of classification systems: Ontogeny of the UDC
CERN Document Server
Salah, Almila Akdag; Suchecki, Krzysztof; Scharnhorst, Andrea; Smiraglia, Richard P
2012-01-01
To classify is to put things in meaningful groups, but the criteria for doing so can be problematic. Study of evolution of classification includes ontogenetic analysis of change in classification over time. We present an empirical analysis of the UDC over the entire period of its development. We demonstrate stability in main classes, with major change driven by 20th century scientific developments. But we also demonstrate a vast increase in the complexity of auxiliaries. This study illustrates an alternative to Tennis' "scheme-versioning" method.
11. On the Implementation of a Land Cover Classification System for SAR Images Using Khoros
Science.gov (United States)
Medina Revera, Edwin J.; Espinosa, Ramon Vasquez
1997-01-01
The Synthetic Aperture Radar (SAR) sensor is widely used to record data about the ground under all atmospheric conditions. The SAR acquired images have very good resolution which necessitates the development of a classification system that process the SAR images to extract useful information for different applications. In this work, a complete system for the land cover classification was designed and programmed using the Khoros, a data flow visual language environment, taking full advantages of the polymorphic data services that it provides. Image analysis was applied to SAR images to improve and automate the processes of recognition and classification of the different regions like mountains and lakes. Both unsupervised and supervised classification utilities were used. The unsupervised classification routines included the use of several Classification/Clustering algorithms like the K-means, ISO2, Weighted Minimum Distance, and the Localized Receptive Field (LRF) training/classifier. Different texture analysis approaches such as Invariant Moments, Fractal Dimension and Second Order statistics were implemented for supervised classification of the images. The results and conclusions for SAR image classification using the various unsupervised and supervised procedures are presented based on their accuracy and performance.
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13. Physical performance as long-term predictor of onset of activities of daily living (ADL) disability
DEFF Research Database (Denmark)
Idland, Gro; Pettersen, Renate; Avlund, Kirsten;
2013-01-01
non-disabled community-dwelling women with a mean age of 79.5 years at baseline. The baseline examinations of physical performance were: functional reach, climbing steps and comfortable walking speed. ADL disability was defined as need of personal assistance in at least one of five basic ADL items...
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10. Classification System for English Language Learners: Issues and Recommendations
Science.gov (United States)
Abedi, Jamal
2008-01-01
High-stakes decisions for the instruction and assessment of English language learner (ELL) students are made based on the premise that ELL classification is a valid dichotomy that distinguishes between those who are proficient in the use of the English language and those who are not. However, recent research findings draw a vague picture of the…
11. Application of Interactive Classification System in University Study Course Comparison
Science.gov (United States)
Birzniece, Ilze; Rudzajs, Peteris; Kalibatiene, Diana; Vasilecas, Olegas; Rencis, Edgars
2015-01-01
The growing amount of information in the world has increased the need for computerized classification of different objects. This situation is present in higher education as well where the possibility of effortless detection of similarity between different study courses would give the opportunity to organize student exchange programmes effectively…
12. Near Earth Asteroids: A Classification System According to Their Shapes
Science.gov (United States)
Acevedo, R. D.; Rocca, M.; Rabassa, J.; Ponce, J. F.; Stinco, S.
2012-09-01
A new way to classify Near Earth Asteroids (NEAs) according to their shapes is proposed. This classification is based on the asteroid roundness and sphericity in the same way that it is used in geological sciences to describe clasts in mechanical sedimentary rocks.
13. Group classification of systems of non-linear reaction-diffusion equations with general diffusion matrix. II. Generalized Turing systems
OpenAIRE
Nikitin, A. G.
2004-01-01
Group classification of systems of two coupled nonlinear reaction-diffusion equation with a diagonal diffusion matrix is carried out. Symmetries of diffusion systems with singular diffusion matrix and additional first order derivative terms are described.
DEFF Research Database (Denmark)
Nielsen, Kristina Tomra; Wæhrens, Eva
2014-01-01
15. R-parametrization and its role in classification of linear multivariable feedback systems
Science.gov (United States)
Chen, Robert T. N.
1988-01-01
A classification of all the compensators that stabilize a given general plant in a linear, time-invariant multi-input, multi-output feedback system is developed. This classification, along with the associated necessary and sufficient conditions for stability of the feedback system, is achieved through the introduction of a new parameterization, referred to as R-Parameterization, which is a dual of the familiar Q-Parameterization. The classification is made to the stability conditions of the compensators and the plant by themselves; and necessary and sufficient conditions are based on the stability of Q and R themselves.
16. Methodological levels of abductive logic and its application in analyzing knowledge classification systems
Directory of Open Access Journals (Sweden)
2015-05-01
Originality/Value: Introduces methodological levels of abductive logic and provides LIS professionals with a new and alternative way for analyzing knowledge classification systems as interpretative and semantic social constructions.
17. EULAR points to consider in the development of classification and diagnostic criteria in systemic vasculitis
DEFF Research Database (Denmark)
Basu, Neil; Watts, Richard; Bajema, Ingeborg;
2010-01-01
The systemic vasculitides are multiorgan diseases where early diagnosis and treatment can significantly improve outcomes. Robust nomenclature reduces diagnostic delay. However, key aspects of current nomenclature are widely perceived to be out of date, these include disease definitions, classific...
18. 5 CFR 9701.231 - Conversion of positions and employees to the DHS classification system.
Science.gov (United States)
2010-01-01
... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Conversion of positions and employees to... Provisions § 9701.231 Conversion of positions and employees to the DHS classification system. (a) This... from the GS system, a prevailing rate system, the SL/ST system, or the SES system, as provided...
19. Methodological levels of abductive logic and its application in analyzing knowledge classification systems
OpenAIRE
2015-01-01
Purpose: This paper distinguishes between “methodology” and “method” and discusses methodological levels of abductive logic as related to the knowledge classification systems. The purpose is to clarify the application of abductive logic for analyzing knowledge classification systems as an alternative for mainstream logics in the field, i.e. inductive and deductive logic. Methodology: Conceptual analysis. Findings: Abductive logic approaches reality as a social construction. It is obviou...
20. A classification of large amplitude oscillations of a spring-pendulum system
Science.gov (United States)
Broucke, R.
1977-01-01
We present a detailed classification of large amplitude oscillations of a non-integrable autonomous system with two degrees of freedom: the spring pendulum system. The classification is made with the method of invariant curves. The results show the importance of three types of motion: periodic, quasi-periodic and semi-ergodic. The numerical results are given for nine different values of the energy constant.
1. Open source, web-based machine-learning assisted classification system
OpenAIRE
Consarnau Pallarés, Mireia Roser
2016-01-01
The aim of this article is to provide a design overview of the web based machine learning assisted multi-user classification system. The design is based on open source standards both for multi-user environment written in PHP using the Laravel framework and a Python based machine learning toolkit, Scikit-Learn. The advantage of the proposed system is that it does not require the domain specific knowledge or programming skills. Machine learning classification tasks are done on the background...
2. A Preliminary Study on the Multiple Mapping Structure of Classification Systems for Heterogeneous Databases
OpenAIRE
Seok-Hyoung Lee; Hwan-Min Kim; Ho-Seop Choe
2012-01-01
While science and technology information service portals and heterogeneous databases produced in Korea and other countries are integrated, methods of connecting the unique classification systems applied to each database have been studied. Results of technologists' research, such as, journal articles, patent specifications, and research reports, are organically related to each other. In this case, if the most basic and meaningful classification systems are not connected, it is difficult to ach...
3. Introduction of the gross motor function classification system in Venezuela - a model for knowledge dissemination
OpenAIRE
Löwing, Kristina; Arredondo, Ynes C.; Tedroff, Marika; Tedroff, Kristina
2015-01-01
Background A current worldwide common goal is to optimize the health and well-being of children with cerebral palsy (CP). In order to reach that goal, for this heterogeneous group, a common language and classification systems are required to predict development and offer evidence based interventions. In most countries in Africa, South America, Asia and Eastern Europe the classification systems for CP are unfamiliar and rarely used. Education and implementation are required. The specific aims ...
4. Reliability of the Multidimensional Pain Inventory and stability of the MPI classification system in chronic back pain
NARCIS (Netherlands)
Verra, M.L.; Angst, F.; Staal, J.B.; Brioschi, R.; Lehmann, S.; Aeschlimann, A.; Bie, R.A. de
2012-01-01
ABSTRACT: BACKGROUND: This cross validation study examined the reliability of the Multidimensional Pain Inventory (MPI) and the stability of the Multidimensional Pain Inventory Classification System of the empirically derived subgroup classification obtained by cluster analysis in chronic musculoske
5. HZI systems for EEG parametrization and classification of psychotropic drugs.
Science.gov (United States)
Itil, T M; Shapiro, D M; Herrmann, W M; Schulz, W; Morgan, V
1979-01-01
The EEG effects of twenty, clinically most frequently used psychotropic drugs and five placebos were studied in 75 male volunteers in five simultaneously designed basic studies. In each of the five studies single oral dosages of five drugs (well known representatives of neuroleptics, antidepressants, anxiolytics and psychostimulants, as well as placebos) were investigated in 15 subjects in a double-blind latin-square research design using the methods of the Quantitative Pharmaco-EEG. The results demonstrated that the therapeutically equivalent effective compounds also have similar effects on human EEG. With a classification rule, based on discriminant function 20, and with a classification rule, based on correlation statistics 19 of 25 compounds could be reclassified into correct clinical-therapeutic psychotropic drug groups. It is suggested that CEEG is an important tool in predicting and describing psychotropic properties of compounds, and should routinely be used in psychotropic drug development. PMID:419164
6. New classification for single-system light treatment
OpenAIRE
Ohshiro, Toshio
2011-01-01
Background and Aims: Although the use of the laser in medical applications has increased dramatically during the last three decades, it is significant that during the last few years non-laser light sources have gained prominence in photomedicine and photosurgery, particularly the use of light-emitting diodes (LEDs) and intense pulsed light (IPL). The author therefore believed it was important to devise a new classification of light/tissue interactions, and that the well-accepted acronym LLLT ...
7. Pediatric patient classification system: improvement of an instrument
OpenAIRE
Ariane Polidoro Dini; Edinêis de Brito Guirardello
2014-01-01
Objective Improve the content validity of the instrument for classification of pediatric patients and evaluate its construct validity. Method A descriptive exploratory study in the measurement of the content validity index, and correlational design for construct validation through exploratory factor analysis. Results The content validity index for indicators was 0.99 and it was 0.97 for graded situations. Three domains were extracted in the construct validation, namely: patient, family an...
8. IMAGE RECONSTRUCTION AND OBJECT CLASSIFICATION IN CT IMAGING SYSTEM
Institute of Scientific and Technical Information of China (English)
张晓明; 蒋大真; 等
1995-01-01
By obtaining a feasible filter function,reconstructed images can be got with linear interpolation and filtered backoprojection techniques.Considering the gray and spatial correlation neighbour informations of each pixel,a new supervised classification method is put forward for the reconstructed images,and an experiment with noise image is done,the result shows that the method is feasible and accurate compared with ideal phantoms.
Science.gov (United States)
Drake, B.
1977-01-01
A hierarchial, four level, standardized system for classifying land use/land cover primarily from remote-sensor data (USGS system) is described. The USGS system was developed for nonmicrowave imaging sensors such as camera systems and line scanners. The USGS system is not compatible with the land use/land cover classifications at different levels that can be made from radar imagery, and particularly from synthetic-aperture radar (SAR) imagery. The use of radar imagery for classifying land use/land cover at different levels is discussed, and a possible revision of the USGS system to more readily accept land use/land cover classifications from radar imagery is proposed.
10. Natural fracture systems on planetary surfaces: Genetic classification and pattern randomness
Science.gov (United States)
Rossbacher, Lisa A.
1987-01-01
One method for classifying natural fracture systems is by fracture genesis. This approach involves the physics of the formation process, and it has been used most frequently in attempts to predict subsurface fractures and petroleum reservoir productivity. This classification system can also be applied to larger fracture systems on any planetary surface. One problem in applying this classification system to planetary surfaces is that it was developed for ralatively small-scale fractures that would influence porosity, particularly as observed in a core sample. Planetary studies also require consideration of large-scale fractures. Nevertheless, this system offers some valuable perspectives on fracture systems of any size.
11. Accurate crop classification using hierarchical genetic fuzzy rule-based systems
Science.gov (United States)
Topaloglou, Charalampos A.; Mylonas, Stelios K.; Stavrakoudis, Dimitris G.; Mastorocostas, Paris A.; Theocharis, John B.
2014-10-01
This paper investigates the effectiveness of an advanced classification system for accurate crop classification using very high resolution (VHR) satellite imagery. Specifically, a recently proposed genetic fuzzy rule-based classification system (GFRBCS) is employed, namely, the Hierarchical Rule-based Linguistic Classifier (HiRLiC). HiRLiC's model comprises a small set of simple IF-THEN fuzzy rules, easily interpretable by humans. One of its most important attributes is that its learning algorithm requires minimum user interaction, since the most important learning parameters affecting the classification accuracy are determined by the learning algorithm automatically. HiRLiC is applied in a challenging crop classification task, using a SPOT5 satellite image over an intensively cultivated area in a lake-wetland ecosystem in northern Greece. A rich set of higher-order spectral and textural features is derived from the initial bands of the (pan-sharpened) image, resulting in an input space comprising 119 features. The experimental analysis proves that HiRLiC compares favorably to other interpretable classifiers of the literature, both in terms of structural complexity and classification accuracy. Its testing accuracy was very close to that obtained by complex state-of-the-art classification systems, such as the support vector machines (SVM) and random forest (RF) classifiers. Nevertheless, visual inspection of the derived classification maps shows that HiRLiC is characterized by higher generalization properties, providing more homogeneous classifications that the competitors. Moreover, the runtime requirements for producing the thematic map was orders of magnitude lower than the respective for the competitors.
12. Exupery volcano fast response system - The event detection and waveform classification system
Science.gov (United States)
Hammer, Conny; Ohrnberger, Matthias
2010-05-01
Volcanic eruptions are often preceded by seismic activity which can be used to quantify the volcanic activity since the number and the size of certain types of seismic events usually increase before periods of volcanic crisis. The implementation of an automatic detection and classification system for seismic signals of volcanic origin allows not only for the processing of large amounts of data in short time, but also provides consistent and time-invariant results. Here, we have developed a system based upon a combination of different methods. To enable a first robust event detection in the continuous data stream different modules are implemented in the real time system Earthworm which is widely distributed in active volcano monitoring observatories worldwide. Among those software modules are classical trigger algorithm like STA/LTA and cross-correlation master event matching which is also used to detect different classes of signals. Furthermore an additional module is implemented in the real time system to compute continuous activity parameters which are also used to quantify the volcanic activity. Most automatic classification systems need a sufficiently large pre-classified data set for training the system. However in case of a volcanic crisis we are often confronted with a lack of training data due to insufficient prior observations because prior data acquisition might be carried out with different equipment at a low number of sites and due to the imminent crisis there might be no time for the time-consuming and tedious process of preparing a training data set. For this reason we have developed a novel seismic event spotting technique in order to be less dependent on the existence of previously acquired data bases of event classes. One main goal is therefore to provide observatory staff with a robust event classification based on a minimum number of reference waveforms. By using a "learning-while-recording" approach we are allowing for the fast build-up of a
13. Development of a classification system for cup anemometers - CLASSCUP
DEFF Research Database (Denmark)
Friis Pedersen, Troels
2003-01-01
Errors associated with the measurements of the wind speed are the major sources of uncertainties in power performance testing of wind turbines. Field comparisons of well-calibrated anemometers show a significant and not acceptable difference. TheEuropean CLASSCUP research project posed......). The classification of three commercial cup anemometersshowed that for the normal category, the best class for horizontal wind speed measurements was class 2 and for vector measurements class 3. The CLASSCUP prototype anemometer got a class 2 as a horizontal anemometer and class 1 as a vector anemometer. Forthe...
14. APPROACHES TO THE CLASSIFICATION OF BRANDS OF PROFESSIONAL FOOTBALL CLUBS IN THE SYSTEM OF SPORTIVE MARKETING
OpenAIRE
Romat, E.; Ostroverh, S.
2014-01-01
This article was told about methods of classification of professional football clubs in the system of sportive marketing in the total commercial conditions of the most popular kind sport, football. Also was told about importance of brand in the professional football club as an active method of increasing trade value multi-functional enterprise in the sport area, which works on business model. The criterions where proposed and also was told about essence of the classification, which is used to...
15. Analysis on Systematic Water Scarcity Based on Establishment of Water Scarcity Classification System
Institute of Scientific and Technical Information of China (English)
2011-01-01
It would be very helpful for making countermeasures against complex water scarcity by analysis on systematic water scarcity.Based on the previous researches on water scarcity classification,a classification system of water scarcity was established according to contributing factors,which comprises three water scarcity categories caused by anthropic factors,natural factors and mixed factors respectively.Accordingly,the concept of systematic water scarcity was proposed,which can be defined as one type of water...
16. Comparing the Utility of the 2000 and 2005 Carnegie Classification Systems in Research on Students' College Experiences and Outcomes
Science.gov (United States)
McCormick, Alexander C.; Pike, Gary R.; Kuh, George D.; Chen, Pu-Shih Daniel
2009-01-01
This study compares the explanatory power of the 2000 edition of Carnegie Classification, the 2005 revision of the classification, and selected variables underlying Carnegie's expanded 2005 classification system using data from the National Survey of Student Engagement's spring 2004 administration. Results indicate that the 2000 and 2005…
17. A study on Pc- based ultrasonic testing system using intelligent ultrasonic flaw classification software
International Nuclear Information System (INIS)
For convenient application of ultrasonic pattern recognition approaches in practical field inspection of weldments, we have developed an intelligent ultrasonic flaw classification system by the novel combination of two ingredients; 1) a PC-based ultrasonic testing system, and 2) an intelligent ultrasonic flaw classification software with an invariant ultrasonic pattern recognition algorithm. Here, key aspects of this intelligent system are addressed including the Pc-based ultrasonic testing system, enhancement of the performance by use of newly proposed ultrasonic features, and feature selection.
18. Terminology and classification aspects of the Bethesda System for Reporting Thyroid Cytopathology
Directory of Open Access Journals (Sweden)
G V Semkina
2012-12-01
Full Text Available The article is devoted to the relevance of Betesda System for Reporting Thyroid Cytopathology. This article summarizes recent data on the main differences and advantages of new classification system. Application of the Betesda System for Reporting Thyroid Cytopathology leads to the increased sensitivity and specificity of FNA.
19. A land use and land cover classification system for use with remote sensor data
Science.gov (United States)
Anderson, James R.; Hardy, Ernest E.; Roach, John T.; Witmer, Richard E.
1976-01-01
The framework of a national land use and land cover classification system is presented for use with remote sensor data. The classification system has been developed to meet the needs of Federal and State agencies for an up-to-date overview of land use and land cover throughout the country on a basis that is uniform in categorization at the more generalized first and second levels and that will be receptive to data from satellite and aircraft remote sensors. The proposed system uses the features of existing widely used classification systems that are amenable to data derived from remote sensing sources. It is intentionally left open-ended so that Federal, regional, State, and local agencies can have flexibility in developing more detailed land use classifications at the third and fourth levels in order to meet their particular needs and at the same time remain compatible with each other and the national system. Revision of the land use classification system as presented in U.S. Geological Survey Circular 671 was undertaken in order to incorporate the results of extensive testing and review of the categorization and definitions.
20. It is time to bring borderline intellectual functioning back into the main fold of classification systems.
Science.gov (United States)
Wieland, Jannelien; Zitman, Frans G
2016-08-01
Borderline intellectual functioning is an important and frequently unrecognised comorbid condition relevant to the diagnosis and treatment of any and all psychiatric disorders. In the DSM-IV-TR, it is defined by IQ in the 71-84 range. In DSM-5, IQ boundaries are no longer part of the classification, leaving the concept without a clear definition. This modification is one of the least highlighted changes in DSM-5. In this article we describe the history of the classification of borderline intellectual functioning. We provide information about it and on the importance of placing it in the right context and in the right place in future DSM editions and other classification systems such as the International Classification of Diseases. PMID:27512590
1. The normalization of citation counts based on classification systems
CERN Document Server
Bornmann, Lutz; Barth, Andreas
2013-01-01
If we want to assess whether the paper in question has had a particularly high or low citation impact compared to other papers, the standard practice in bibliometrics is to normalize citations in respect of the subject category and publication year. A number of proposals for an improved procedure in the normalization of citation impact have been put forward in recent years. Against the background of these proposals this study describes an ideal solution for the normalization of citation impact: in a first step, the reference set for the publication in question is collated by means of a classification scheme, where every publication is associated with a single principal research field or subfield entry (e. g. via Chemical Abstracts sections) and a publication year. In a second step, percentiles of citation counts are calculated for this set and used to assign the normalized citation impact score to the publications (and also to the publication in question).
2. The Normalization of Citation Counts Based on Classification Systems
Directory of Open Access Journals (Sweden)
Andreas Barth
2013-08-01
Full Text Available If we want to assess whether the paper in question has had a particularly high or low citation impact compared to other papers, the standard practice in bibliometrics is to normalize citations in respect of the subject category and publication year. A number of proposals for an improved procedure in the normalization of citation impact have been put forward in recent years. Against the background of these proposals, this study describes an ideal solution for the normalization of citation impact: in a first step, the reference set for the publication in question is collated by means of a classification scheme, where every publication is associated with a single principal research field or subfield entry (e.g., via Chemical Abstracts sections and a publication year. In a second step, percentiles of citation counts are calculated for this set and used to assign the normalized citation impact score to the publications (and also to the publication in question.
3. Pediatric patient classification system: improvement of an instrument
Directory of Open Access Journals (Sweden)
Ariane Polidoro Dini
2014-10-01
Full Text Available Objective Improve the content validity of the instrument for classification of pediatric patients and evaluate its construct validity. Method A descriptive exploratory study in the measurement of the content validity index, and correlational design for construct validation through exploratory factor analysis. Results The content validity index for indicators was 0.99 and it was 0.97 for graded situations. Three domains were extracted in the construct validation, namely: patient, family and therapeutic procedures, with 74.97% of explained variance. The instrument showed evidences of content and construct validity. Conclusion The validation of the instrument occurred under the approach of family-centered care, and allowed incorporating some essential needs of childhood such as playing, interaction and affection in the content of the instrument.
4. Young Planetary Nebulae: Hubble Space Telescope Imaging and a New Morphological Classification System
CERN Document Server
Sahai, Raghvendra; Villar, Gregory G
2011-01-01
Using Hubble Space Telescope images of 119 young planetary nebulae, most of which have not previously been published, we have devised a comprehensive morphological classification system for these objects. This system generalizes a recently devised system for pre-planetary nebulae, which are the immediate progenitors of planetary nebulae (PNs). Unlike previous classification studies, we have focussed primarily on young PNs rather than all PNs, because the former best show the influences or symmetries imposed on them by the dominant physical processes operating at the first and primary stage of the shaping process. Older PNs develop instabilities, interact with the ambient interstellar medium, and are subject to the passage of photoionization fronts, all of which obscure the underlying symmetries and geometries imposed early on. Our classification system is designed to suffer minimal prejudice regarding the underlying physical causes of the different shapes and structures seen in our PN sample, however, in many...
5. [Diseases of the digestive system and a system for patient classification: diagnostic-related groups (DRG)].
Science.gov (United States)
Poves Martínez, E
1996-10-01
In the last years different classification systems for hospitalized patients have been developed in the United States, that allow to evaluate different aspects of any Hospital: The quality, the efficacy and the efficiency. The classification of "The Diagnosis Related Groups" (DRG) relates the hospitalized patients with the expenses that they generate, and it is the most used in Europe. In the version DRG-All Patient, all the diagnoses and procedures of the hospitalized patients, using the International Classification of Diseases, are divided in to 25 Major Diagnostic Categories (MDC) where each one excludes all the others. We describe the behavior with respect to the age, sex and stay of all the GDR integrated in the CDM 6 and 7: diseases and disorders of the digestive tract, and diseases and disorders of the hepatobiliary system and the pancreas. The study has been carried out with a national data base of two millions of cases seen from 214 acute-care Hospitals. The MDC number 6 is the most frequent, with an important number of patients in the pediatric age; it is more frequent in males; the average stay is 8.59 days and 19 GDR (36.5%) have a variation coefficient greater than one. The other MDC, number 7 is less frequent, the majority of the patients are between 60-80 years of age, the average stay is 12.2 days with a coefficient of variation greater than one in 4 GDR (17.4%). Clinical Services should know the characteristics and behavior of their patients, as well as the comparison with the national data bases. This may allow a control of the quality and the costs by using a common "language" with the managers. PMID:8983307
6. A Process for the Representation of openEHR ADL Archetypes in OWL Ontologies.
Science.gov (United States)
Porn, Alex Mateus; Peres, Leticia Mara; Didonet Del Fabro, Marcos
2015-01-01
ADL is a formal language to express archetypes, independent of standards or domain. However, its specification is not precise enough in relation to the specialization and semantic of archetypes, presenting difficulties in implementation and a few available tools. Archetypes may be implemented using other languages such as XML or OWL, increasing integration with Semantic Web tools. Exchanging and transforming data can be better implemented with semantics oriented models, for example using OWL which is a language to define and instantiate Web ontologies defined by W3C. OWL permits defining significant, detailed, precise and consistent distinctions among classes, properties and relations by the user, ensuring the consistency of knowledge than using ADL techniques. This paper presents a process of an openEHR ADL archetypes representation in OWL ontologies. This process consists of ADL archetypes conversion in OWL ontologies and validation of OWL resultant ontologies using the mutation test.
DEFF Research Database (Denmark)
Nielsen, Kristina Tomra; Petersen, Rikke S.; Wæhrens, Eva Ejlersen
2015-01-01
8. A Process for the Representation of openEHR ADL Archetypes in OWL Ontologies.
Science.gov (United States)
Porn, Alex Mateus; Peres, Leticia Mara; Didonet Del Fabro, Marcos
2015-01-01
ADL is a formal language to express archetypes, independent of standards or domain. However, its specification is not precise enough in relation to the specialization and semantic of archetypes, presenting difficulties in implementation and a few available tools. Archetypes may be implemented using other languages such as XML or OWL, increasing integration with Semantic Web tools. Exchanging and transforming data can be better implemented with semantics oriented models, for example using OWL which is a language to define and instantiate Web ontologies defined by W3C. OWL permits defining significant, detailed, precise and consistent distinctions among classes, properties and relations by the user, ensuring the consistency of knowledge than using ADL techniques. This paper presents a process of an openEHR ADL archetypes representation in OWL ontologies. This process consists of ADL archetypes conversion in OWL ontologies and validation of OWL resultant ontologies using the mutation test. PMID:26262167
9. Dengue disease severity in Indonesian children: An evaluation of the World Health Organization classification system
NARCIS (Netherlands)
T.E. Setiati (Tatty); A.T.A. Mairuhu; P. Koraka (Penelopie); M. Supriatna (Mohamad); M.R. Mac Gillavry (Melvin); D.P.M. Brandjes (Dees); A.D.M.E. Osterhaus (Albert); J.W.M. van der Meer (Jos); E.C.M. van Gorp (Eric); A. Soemantri (Augustinus)
2007-01-01
textabstractBackground: Dengue disease severity is usually classified using criteria set up by the World Health Organization (WHO). We aimed to assess the diagnostic accuracy of the WHO classification system and modifications to this system, and evaluated their potential practical usefulness. Method
10. Local classification of stable geometric solutions of systems of quasilinear first-order PDE
Institute of Scientific and Technical Information of China (English)
李兵; 李养成
2002-01-01
Systems of quasilinear first order PDE are studied in the framework of contact manifold. All of the local stable geometric solutions of such systems are classified by using versal deformation and the classification of stable map germs of type ∑1 in singularity theory.
11. International society of neuropathology-haarlem consensus guidelines for nervous system tumor classification and grading
NARCIS (Netherlands)
Louis, D.N.; Perry, A.; Burger, P.; Ellison, D.W.; Reifenberger, G.; Deimling, A. Von; Aldape, K.; Brat, D.; Collins, V.P.; Eberhart, C.; Figarella-Branger, D.; Fuller, G.N.; Giangaspero, F.; Giannini, C.; Hawkins, C.; Kleihues, P.; Korshunov, A.; Kros, J.M.; Lopes, M. Beatriz; Ng, H.K.; Ohgaki, H.; Paulus, W.; Pietsch, T.; Rosenblum, M.; Rushing, E.; Soylemezoglu, F.; Wiestler, O.; Wesseling, P.
2014-01-01
Major discoveries in the biology of nervous system tumors have raised the question of how non-histological data such as molecular information can be incorporated into the next World Health Organization (WHO) classification of central nervous system tumors. To address this question, a meeting of neur
12. Structure and contents of layered classification system of digital geomorphology for China
Institute of Scientific and Technical Information of China (English)
CHENG Weiming; ZHOU Chenghu; LI Bingyuan; SHEN Yuancun; ZHANG Baiping
2011-01-01
This paper presents the structure and contents of a standardized layered classification system of digital geomorphology for China.This digital classification method combines landforms characteristics of morphology with genesis.A total of 15 categories of exogenic and endogenic forces are divided into two broad categories:morpho-genetic and morpho-structural landforms.Polygon patches are used to manage the morpho-genetic types,and solitary points,lines and polygons are used to manage the morpho-structural types.The classification method of digital morpho-genetic types can be divided into seven layers,i.e.basic morphology and altitude,genesis,sub-genesis,morphology,micro-morphology,slope and aspect,material and lithology.The method proposes combinations of matrix forms based on layered indicators.The attributes of every landform types are obtained from all or some of the seven layers.For the 15 forces categories,some classification indicators and calculation methods are presented for the basic morphology,the morphologic and sub-morphologic landforms of the morpho-genetic types.The solitary polygon,linear and point types of morpho-structural landforms are presented respectively.The layered classification method can meet the demands of scale-span geomorphologic mapping for the national primary scales from 1:500,000 to 1:1,000,000.The layers serve as classification indicators,and therefore can be added and reduced according to mapping demands,providing flexible expandability.
13. Classification of Aeronautics System Health and Safety Documents
Data.gov (United States)
National Aeronautics and Space Administration — Most complex aerospace systems have many text reports on safety, maintenance, and associated issues. The Aviation Safety Reporting System (ASRS) spans several...
14. Listeria monocytogenes DNA Glycosylase AdlP Affects Flagellar Motility, Biofilm Formation, Virulence, and Stress Responses
Science.gov (United States)
Zhang, Ting; Bae, Dongryeoul
2016-01-01
ABSTRACT The temperature-dependent alteration of flagellar motility gene expression is critical for the foodborne pathogen Listeria monocytogenes to respond to a changing environment. In this study, a genetic determinant, L. monocytogenes f2365_0220 (lmof2365_0220), encoding a putative protein that is structurally similar to the Bacillus cereus alkyl base DNA glycosylase (AlkD), was identified. This determinant was involved in the transcriptional repression of flagellar motility genes and was named adlP (encoding an AlkD-like protein [AdlP]). Deletion of adlP activated the expression of flagellar motility genes at 37°C and disrupted the temperature-dependent inhibition of L. monocytogenes motility. The adlP null strains demonstrated decreased survival in murine macrophage-like RAW264.7 cells and less virulence in mice. Furthermore, the deletion of adlP significantly decreased biofilm formation and impaired the survival of bacteria under several stress conditions, including the presence of a DNA alkylation compound (methyl methanesulfonate), an oxidative agent (H2O2), and aminoglycoside antibiotics. Our findings strongly suggest that adlP may encode a bifunctional protein that transcriptionally represses the expression of flagellar motility genes and influences stress responses through its DNA glycosylase activity. IMPORTANCE We discovered a novel protein that we named AlkD-like protein (AdlP). This protein affected flagellar motility, biofilm formation, and virulence. Our data suggest that AdlP may be a bifunctional protein that represses flagellar motility genes and influences stress responses through its DNA glycosylase activity. PMID:27316964
15. Open Fractures of the Hand: Review of Pathogenesis and Introduction of a New Classification System.
Science.gov (United States)
Tulipan, Jacob E; Ilyas, Asif M
2016-01-01
Open fractures of the hand are a common and varied group of injuries. Although at increased risk for infection, open fractures of the hand are more resistant to infection than other open fractures. Numerous unique factors in the hand may play a role in the altered risk of postinjury infection. Current systems for the classification of open fractures fail to address the unique qualities of the hand. This article proposes a novel classification system for open fractures of the hand, taking into account the factors unique to the hand that affect its risk for developing infection after an open fracture.
16. A state of the art ash classification system - China Light and Power Company Limited, Hong Kong
Energy Technology Data Exchange (ETDEWEB)
Meijers, S.J.; Brunskill, J. [Bateman Material Handling Ltd., Wilbart (South Africa)
1994-12-31
The pressures from environmentalists are ever increasing in todays highly polluted world. One of the hardest hit are the power stations generating gaseous liquid and solid pollutants. In recent times, the waste fly ash has proven itself to be an important commodity in the cementitious industry if used in the correct form. In order to meet world standards for the particle size criteria, sophisticated equipment needs to be used in a fly ash classification system. This paper highlights the major operating areas in the worlds latest fly ash classification system recently commissioned in Hong Kong. 3 refs., 5 figs.
17. Data Processing And Machine Learning Methods For Multi-Modal Operator State Classification Systems
Science.gov (United States)
Hearn, Tristan A.
2015-01-01
This document is intended as an introduction to a set of common signal processing learning methods that may be used in the software portion of a functional crew state monitoring system. This includes overviews of both the theory of the methods involved, as well as examples of implementation. Practical considerations are discussed for implementing modular, flexible, and scalable processing and classification software for a multi-modal, multi-channel monitoring system. Example source code is also given for all of the discussed processing and classification methods.
18. Classification in Australia.
Science.gov (United States)
McKinlay, John
Despite some inroads by the Library of Congress Classification and short-lived experimentation with Universal Decimal Classification and Bliss Classification, Dewey Decimal Classification, with its ability in recent editions to be hospitable to local needs, remains the most widely used classification system in Australia. Although supplemented at…
19. Cross-Cultural Perspectives on the Classification of Children with Disabilities: Part II. Implementing Classification Systems in Schools
Science.gov (United States)
McLaughlin, Margaret J.; Dyson, Alan; Nagle, Katherine; Thurlow, Martha; Rouse, Martyn; Hardman, Michael; Norwich, Brahm; Burke, Phillip J.; Perlin, Michael
2006-01-01
This article is the second in a 2-part synthesis of an international comparative seminar on the classification of children with disabilities. In this article, the authors discuss classification frameworks used in identifying children for the purpose of providing special education and related services. The authors summarize 7 papers that addressed…
20. Software component composition based on ADL and Middleware
Institute of Scientific and Technical Information of China (English)
2001-01-01
How to compose prefabricated components is a key issue in component-based reuse. Research on Software Architecture (SA) and Component-based Software Development (CBSD) provides two hopeful solutions from different perspectives. SA provides a top-down approach to realizing component-based reuse. However, it pays insufficient attention to the refinement and implementation of the architectural descriptions, and does not provide the necessary capability to automate the transformation or composition to form a final executable application. CBSD provides a bottom-up way by using existing middleware infrastructures. However, these technologies do not take into account the systematic methodology that can guide the CBSD process, especially the component composition at higher abstract levels. We argue that it is a natural solution to combine these two approaches. In this paper, an architecture-based component composition approach is presented. In this way, SA description, using mapping rules and mini-tools to narrow the gap between design and implementation, is used as the blueprint and middleware technology as the runtime scaffold for component composition. Our approach presents an ADL, which supports user-defined connectors and has an extensible framework, to specify software architectures. To map a SA description into implementation, it is necessary to map it first to an OO design model described in UML, then to the final implementation. The architectural description can be mapped into source code or executable code by using some ORB conforming to CORBA standard. Also a toolkit is provided to support this approach efficiently. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.42084190249443054, "perplexity": 5042.319437241109}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-22/segments/1495463608956.34/warc/CC-MAIN-20170527152350-20170527172350-00320.warc.gz"} |
https://seop.illc.uva.nl/entries/causal-explanation-science/ | # Causal Approaches to Scientific Explanation
First published Fri Mar 17, 2023
This entry discusses some accounts of causal explanation developed after approximately 1990. For a discussion of earlier accounts of explanation including the deductive-nomological (DN) model, Wesley Salmon’s statistical relevance and causal mechanical models, and unificationist models, see the general entry on scientific explanation. Recent accounts of non-causal explanation will be discussed in a separate entry. In addition, a substantial amount of recent discussion of causation and causal explanation has been conducted within the framework of causal models. To avoid overlap with the entry on causal models we do not discuss this literature here.
Our focus in this entry is on the following three accounts – Section 1 those that focus on mechanisms and mechanistic explanations, Section 2 the kairetic account of explanation, and Section 3 interventionist accounts of causal explanation. All of these have as their target explanations of why or perhaps how some phenomenon occurs (in contrast to, say, explanations of what something is, which is generally taken to be non-causal) and they attempt to capture causal explanations that aim at such explananda. Section 4 then takes up some recent proposals having to do with how causal explanations may differ in explanatory depth or goodness. Section 5 discusses some issues having to do with what is distinctive about causal (as opposed to non-causal) explanations.
We also make the following preliminary observation. An account of causal explanation in science may leave open the possibility that there are other sorts of explanations of a non-causal variety (it is just that the account does not claim to capture these, at least without substantial modifications) or it may, more ambitiously, claim that all explanations of the why/how variety are, at least in some extended sense, causal. The kairetic model makes this latter claim, as do many advocates of mechanistic models. By contrast, interventionist models, need not deny that there are non-causal explanations, although the version described below does not attempt to cover such explanations. Finally, we are very conscious that, for reasons of space, we omitted many recent discussions of causal explanation from this entry. We provide brief references to a number of these at the end of this article (Section 6).
## 1. Mechanisms and Mechanistic Explanations
Many accounts of causation and explanation assign a central importance to the notion of mechanism. While discussions of mechanism are present in the early modern period, with the work of Descartes and others, a distinct and very influential research program emerged with the “new mechanist” approaches of the late twentieth and early twenty-first century. This section focuses on work in this tradition.
Wesley Salmon’s causal mechanical (CM) model of explanation (Salmon 1984) was an influential late twentieth century precursor to the work on mechanisms that followed. The CM model is described in the SEP entry on scientific explanation and readers are referred to this for details. For present purposes we just note the following. First, Salmon’s model is proposed as an alternative to the deductive-nomological (DN) model and the “new mechanist” work that follows also rejects the DN model, although in some cases for reasons somewhat different from Salmon’s. Like the CM model and in contrast to the DN model, the new mechanist tradition downplays the role of laws in explanation, in part because (it is thought) there are relatively few laws in the life sciences, which are the primary domain of application of recent work on mechanisms. Second, although Salmon provides an account of causal relationships that are in an obvious sense “mechanical”, he focuses virtually entirely on physical examples (like billiard ball collisions) rather than examples from the life sciences. Third Salmon presents his model as an “ontic” account of explanation, according to which explanations are things or structures in the world and contrasts this with what he regarded as “epistemic” accounts of explanation (including in his view, the DN model) which instead conceive of explanations as representations of what is in the world (Salmon 1984). This “ontic” orientation has been important in the work of some of the new mechanists, such as Craver (2007a), but less so for others. Finally, Salmon’s model introduces a distinction between the “etiological” aspects of explanation which have to do with tracing the causal history of some event E and the “constitutive” aspects which have to do with “the internal causal mechanisms that account for E’s nature” (Salmon 1984: 275). This focus on the role of “constitution” is retained by a number of the new mechanists.
We may think of the “new mechanism” research program properly speaking as initiated by writers like Bechtel and Richardson (1993 [2010]), Glennan (1996, 1997), and Machamer, Darden, and Craver (2000). Although these writers provide accounts that differ in detail,[1] they share common elements: mechanisms are understood as causal systems, exhibiting a characteristic organization, with multiple causal factors that work together in a coordinated manner to produce some effect of interest. Providing a mechanistic explanation involves explaining an outcome by appealing to the causal mechanism that produces it. The components of a mechanism stand in causal relationships but most accounts conceptualize the relationship between these components and the mechanism itself as a part-whole or “constitutive relationship” – e.g., a human cell is constituted by various molecules, compounds and organelles, the human visual system is constituted by various visual processing areas (including V1–V5) and an automobile engine may be constituted by pistons, cylinders, camshaft and carburetor, among other components. Such part/whole relations are generally conceptualized as non-causal – that is, constitution is seen as a non-causal relationship. Thus, on these accounts, mechanisms are composed of or constituted by lower-level causal parts that interact together to produce the higher-level behavior of the (whole) mechanism understood as some effect of interest. This part-whole picture gives mechanistic explanation a partially reductive character, in the sense that higher-level outcomes characterizing the whole mechanism are explained by the lower-level causes that produce them. In many accounts this is depicted in nested, hierarchical diagrams describing these relations between levels of mechanisms (Craver 2007a).
Although philosophical discussion has often focused on the role of constitutive relations in mechanisms and how best to understand these, it is, as noted above, also common to think of mechanism as consisting of factors or components that stand in causal (“etiological”) relations to one another with accompanying characteristic spatial, temporal or geometrical organization. This feature of mechanism and mechanistic explanation is emphasized by Illari and Williamson (2010, 2012) and Woodward (2002, 2013). In particular, elucidating a mechanism is often understood as involving the identification of “mediating” factors that are “between” the input to the mechanism and its eventual output – “between” both in the sense of causally between and in the sense that the operation of these mediating factors often can be thought of as spatially and temporally between the input to the mechanism and its output. (The causal structure and the spatiotemporal structure thus “mirror” or run parallel to each other.) Often this information about intermediates can be thought of as describing the “steps” by which the mechanism operates over time. For example, mechanistic explanations of the action potential will cite the (anatomical) structure of the neural cell membrane, the relative location and structure of ion channels (in this membrane), ion types on either side of this membrane, and the various temporal steps in the opening and closing of ion channels that generate the action potential. A step-by-step description of this mechanism cites all of these parts and their interactions from the beginning of the causal process to the end. In this respect a description of a mechanism will provide more detail than, say, directed acyclic graphs which describe causal relations among variables but do not provide spatio-temporal or geometrical information.
A hotly debated issue in the literature on mechanisms concerns the amount of detail descriptions of mechanisms or mechanistic explanations need to contain. While some mechanists suggest that mechanisms (or their descriptions) can be abstract or lacking in detail (Levy & Bechtel 2012), it is more commonly claimed that mechanistic explanations must contain significant detail – perhaps as much “relevant” detail as possible or at least that this should be so for an “ideally complete description” of a mechanism (see Craver 2006 and the discussion in Section 4). Thus, a mere description of an input-output causal relation, even if correct, lacks sufficient detail to count as a description of a mechanism. For example, a randomized control trial can support the claim that drug X causes recovery Y, but this alone doesn’t elucidate the “mechanism of action” of the drug. Craver (2007a: 113–4) goes further, suggesting that even models that provide substantial information about anatomical structures and causal intermediaries are deficient qua mechanistic explanations if they omit detail thought to be relevant. For example, the original Hodgkin-Huxley (HH) model of the action potential identified a role for the opening and closing of membrane channels but did not specify the molecular mechanisms involved in the opening and closing of those channels. Craver (2006, 2007a, 2008) takes this to show that the HH model is explanatorily deficient – it is a “mechanism sketch” rather than a fully satisfactory mechanistic explanation. (This is echoed by Glennan who states that the monocausal model of disease – a one cause-one effect relationship – is “the sketchiest of mechanism sketches” [Glennan 2017: 226].) This “the more relevant detail the better” view has in turn been criticized by those who think that one can sometimes improve the quality of an explanation or at least make it no worse by omitting detail. For such criticism see, e.g., Batterman and Rice (2014), Levy (2014), Chirimuuta (2014), Ross (2015, 2020), etc. and for a response see by Craver and Kaplan (2020).[2]
The new mechanists differ among themselves in their views of causation and their attitudes toward general theories of causation found in the philosophical literature. Since a mechanism involves components standing in causal relations, one might think that a satisfactory treatment of mechanisms should include an account of what is meant by “causal relations”. Some mechanists have attempted to provide such an account. For example, Craver (2007a) appeals to elements of Woodward’s interventionist account of causation in this connection and for other purposes – e.g., to provide an account of constitutive relevance (Craver 2007b). By contrast, Glennan (1996, 2017) argues that the notion of mechanism is more fundamental than that of causation and that the former can be used to elucidate the latter – roughly, X causes Y when there is a mechanism connecting X to Y. Of course, for Glennan’s project this requires that mechanism is elucidated in a way that doesn’t appeal to the notion causation. Yet another view, inspired by Anscombe (1971) and advocated by Machamer, Darden, and Craver (MDC) (2000), Machamer (2004) and others, eschews any appeal to general theories of causation and instead describes the causal features of mechanism in terms of specific causal verbs. For example, according to MDC, mechanisms involve entities that engage in “activities”, with examples of the latter including “attraction”, “repulsion”, “pushing” and so on (MDC 2000: 5). It is contended that no more general account according to which these are instances of some common genus (causation) is likely to be illuminating. A detailed evaluation of this claim is beyond the scope of this entry, but we do wish to note that relatively general theories of causation that go beyond the cataloging of particular causal activities now flourish not just in philosophy but in disciplines like computer science and statistics (Pearl 2000 [2009]; Morgan & Winship, 2014) where they are often thought to provide scientific and mathematical illumination.
Another issue raised by mechanistic accounts concerns their scope. As we have seen these accounts were originally devised to capture a form of explanation thought to be widespread in the life sciences. This aspiration raises several questions. First, are all explanations in the life sciences “mechanistic” in the sense captured by some model of mechanistic explanation? Many new mechanists have answered this question in the affirmative but there has been considerable pushback to this claim, with other philosophers claiming that there are explanations in the life sciences that appeal to topological or network features (Lange 2013; Huneman 2010; Rathkopf 2018; Kostić 2020; Ross 2021b), to dynamical systems models (Ross 2015) and to other features deemed “non-mechanical” as with computational models in neuroscience (Chirimuuta 2014, 2018). This debate raises the question of how broadly it is appropriate to extend the notion of “mechanism” (Silberstein & Chemero 2013).
While the examples above are generally claimed to be non-causal and non-mechanistic, a further question is whether there are also types of causal explanation that are non-mechanistic. Answering this question depends, in part, on how “mechanism” is defined and what types of causal structures count as “mechanisms”. If mechanisms have the particular features mentioned above – part-whole relationships, some significant detail, and mechanical interactions – it would seem clear that some causal explanations are non-mechanistic in the sense that they cite causal systems and information with different features. For example, causal systems including pathways, networks, and cascades have been advanced as important types of causal structures that do not meet standard mechanism characteristics (Ross 2018, 2021a, forthcoming). Other examples include complex causal processes that lack machine-like and fixed causal parts (Dupré 2013). This work often questions whether “mechanism” fruitfully captures the diversity of causal structures and causal explanations that are present in scientific contexts.
There is an understandable tendency among mechanists to attempt to extend the scope of their accounts as far as possible but presumably the point of the original project was that mechanistic explanations have some distinctive features. Extending the models too far may lead to loss of sight of these. The problem is compounded by the fact that “mechanism” is used in many areas of science as general term of valorization or approval, as is arguably the case for talk of the “mechanism” of natural selection or of “externalizing tendencies” as a “mechanism” leading to substance abuse. The question is whether these candidates for mechanisms have enough in common with, say, the mechanism by which the action potential is produced to warrant the treatment of both by some common model. Of course, this problem also arises when one considers the extent to which talk of mechanisms is appropriate outside of the life sciences. Chemists talk of mechanisms of reaction, physicists of the Higgs mechanism, and economists of mechanism design, but again this raises the question of whether an account of mechanistic explanation should aspire to cover all of these.
## 2. The Kairetic Account of Explanation
This account is developed by Michael Strevens in his Depth (2008) and in a number of papers (2004, 2013, 2018). Strevens describes his theory as a “two factor” account (Strevens 2008: 4). The first factor – Strevens’ starting point – is the notion of causation or dependence (Strevens calls it “causal influence”) that figures in fundamental physics. Strevens is ecumenical about what this involves. He holds that a number of different philosophical treatments of causal influence – conserved quantity, counterfactual or interventionist – will fit his purposes. This notion of causal influence is then used as input to an account of causal explanation – Strevens’ second factor. A causal explanation of an individual event e (Strevens’ starting point) assembles all and only those causal influences that make a difference to (are explanatorily relevant to) e. A key idea here is the notion of causal entailment (Strevens 2008: 74).[3] A set of premises that causally entail that e occurs deductively entail this claim and do this in a way that “mirrors” the causal influences (ascertained from the first stage) leading to e. This notion of mirroring is largely left at an intuitive level but as an illustration a derivation of an effect from premises describing the cause mirrors the causal influences leading to the effect while the reverse derivation from effect to cause does not. However, more than mirroring is required for causal explanation: The premises in a causal entailment of the sort just described are subjected to a process (a kind of “abstraction”) in which premises that are not necessary for the entailment of e are removed or replaced with weaker alternatives that are still sufficient to entail e – the result of this being to identify factors which are genuinely difference-makers or explanatorily relevant to e. The result is what Strevens calls a “stand-alone” explanation for e (Strevens 2008: 70). (Explanatory relevance or difference-making is thus understood in terms of what, so to speak, is minimally required for causal entailment, constrained by a cohesiveness requirement described below, rather than, as in some other models of explanation, in terms of counterfactuals or statistical relevance.) As an illustration, if the event e is the shattering of a window the causal influences on e, identified from fundamental physics, will be extremely detailed and will consist of influences that affect fine grained features of e’s occurrence, having to do, e.g., with exactly how the window shatters. But to the extent that the explanandum is just whether e occurs most of those details will be irrelevant in the sense that they will affect only the details of how the shattering occurs and not whether it occurs at all. Dropping these details will result in a derivation that still causally entails e. The causal explanation of e is what remains after all such details have been dropped and only what is necessary for the causal entailment of e is retained.
As Strevens is fully aware, this account faces the following apparent difficulty. There are a number of different causal scenarios that realize causes of bottle shatterings – the impact of rocks but also, say, sonic booms (cf. Hall 2012). In Strevens’ view, we should not countenance causal explanations that disjoin causal models that describe such highly different realizers, even though weakening derivations via the inclusion of such disjunctions may preserve causal entailment. Strevens’ solution appeals to the notion of cohesion; when different processes serve as “realizers” for the causes of e, these must be “cohesive” in the sense that they are “causally contiguous” from the point of view of the underlying physics. Roughly, contiguous causal processes are those that are nearby or neighbors to one another in a space provided by fundamental physics.[4] Sonic booms and rock impacts do not satisfy this cohesiveness requirement and hence models involving them as disjunctive premises are excluded. Fundamental physics is thus the arbitrator of whether upper-level properties with different realizers are sufficiently similar to satisfy the cohesion requirement. Or at least this is so for deep “stand alone” explanations in contrast to those explanations that are “framework” dependent (see below).
As Strevens sees it, a virtue of his account is that it separates difficult (“metaphysical”) questions about the nature of the causal relationships (at least as these are found in physics which is Strevens’ starting point) from issues about causal explanation, which are the main focus of the kairetic account. It also follows that most of the causal claims that we consider in common sense and in science (outside of fundamental physics) are in fact claims about causal explanation and explanatory relevance as determined by the kairetic abstraction procedure rather than claims about causation per se. In effect when one claims that “aspirin causes headache relief” one is making a rather complicated causal explanatory claim about the upshot of the application of the abstraction procedure to the causal claims that, properly speaking, are provided by physics. This contrasts with an account in which causal claims outside of physics are largely univocal with causal claims (assuming that there are such) within physics.
We noted above that Strevens imposes a cohesiveness requirement on his abstraction procedure. This seems to have the consequence that upper-level causal generalizations that have realizers that are rather disparate from the point of view of the underlying physics are defective qua explainers, even though there are many examples of such generalizations that (rightly or wrongly) are regarded as explanatory. Strevens addresses this difficulty by introducing the notion of a framework – roughly a set of presuppositions for an explanation. When scientists “framework” some aspect of a causal story, they put that aspect aside (it is presupposed rather an explicit part of the explanation) and focus on getting the story right for the part that remains. A common example is to framework details of implementation, in effect black-boxing the low-level causal explanation of why certain parts of a system behave in the way they do. The resulting explanation simply presupposes that these parts do what they do, without attempting to explain why. Consequently, the black boxes in such explanations are not subject to the cohesion requirement, because they are not the locus of explanatory attention . Thus although explanations appealing to premises with disparate realizers are defective when considered by themselves as stand-alone explanations, we may regard such explanations as dependent on a framework with the framework incorporating information about a presupposed mechanism that satisfies the coherence constraint.[5] When this is the case, the explanation will be acceptable qua frameworked explanation. Nonetheless in such cases the explanation should in principle be deepened by making explicit the information presupposed in the framework.
Strevens describes his account as “descriptive” rather than “normative” in aspiration. Presumably, however, it is not intended as a description of the bases on which lay people or scientists come to accept causal explanations outside of fundamental physics – people don’t actually go through the abstraction from fundamental physics process that Strevens describes when they arrive at or reason about upper-level causal explanations. Instead, as we understand his account, it is intended to characterize something like what must be the case from the point of view of fundamental physics for upper-level causal judgments to be explanatory – the explanatory upper-level claims must fit with physics in the right way as specified in Strevens’ abstraction procedure and the accompanying cohesiveness constraint.[6] Perhaps then the account is intended to be descriptive in the sense that the upper-level causal explanations people regard as satisfactory do in fact satisfy the constraints he describes. In addition, the account is intended to be descriptive in the sense that it contends that as a matter of empirical fact people regard their explanations as committed to various claims about the underlying physics even if these claims are presently unknown – e.g., to claims about the cohesiveness of these realizers.[7] At the same time the kairetic account is also normative in the sense that it judges that explanations that fail to satisfy the constraints of the abstraction procedure are in some way unsatisfactory – thus people are correct to have the commitments described above.
Depth also contains an interesting treatment of the role of idealizations in explanation. It is often thought that idealizations involve the presence of “falsehoods”, or “distortions”. Strevens claims that these “false” features involve claims that do not have to do with difference-makers, in the sense captured by the abstraction procedure. Thus, according to the kairetic model, it does not matter if idealizations involve falsehoods or if they omit certain information since the falsehoods or omitted information do not concern difference-makers – their presence thus does not detract from the resulting explanation. Moreover, we can think of idealizations as conveying useful information about which factors are not difference-makers.
The kairetic account covers a great deal more that we lack the space to discuss including treatments of what Strevens calls “entanglement”, equilibrium explanations, statistical explanation and much else.
As is always the case with ambitious theories in philosophy, there have been a number of criticisms of the kairetic model. Here we mention just two. First, the kairetic model assumes that all legitimate explanation is causal or at least that all explanation must in some way reference or connect with causal information. (A good deal of the discussion in Depth is concerned to show that explanations that might seem to be non-causal can nonetheless be regarded as working by conveying causal information.) This claim that all explanation is causal is by no means an implausible idea – until recently it was widely assumed in the literature on explanation (Skow 2014). Nonetheless this idea has recently been challenged by a number of philosophers (Baker 2005; Batterman 2000, 2002, 2010a; Lange 2013, 2016; Lyon 2012; Pincock 2007). Relatedly, the kairetic account assumes that fundamental physics is “causal” – physics describes causal relations, and indeed lots of causal relations, enough to generate a large range of upper-level causal explanations when the abstraction procedure is applied. Some hold instead that the dependence relations described in physics are either not causal at all (causation being a notion that applies only to upper-level or macroscopic relationships) or else that these dependence relations lack certain important features (such as asymmetry) that are apparently present in causal explanatory claims outside of physics (Ney 2009, 2016). These claims about the absence of causation in physics are controversial but if correct, it follows that physics does not provide the input that Strevens’ account needs.[8]
A second set of issues concern the kairetic abstraction process. Here there are several worries. First, the constraints on this process have struck some as vague since they involve judgments of cohesiveness of realizers from the point of view of underlying physics. Does physics or any other science really provide a principled, objective basis for such judgments? Second, it seems, as suggested above, that upper-level causal explanations often generalize over realizers that are very disparate from the point of view of the underlying physics. Potochnik (2011, 2017) focuses on the example, also discussed by Strevens, of the Lotka-Volterra (LV) equations which are applied to a large variety of different organisms that stand in predator/prey relations. Strevens uses his ideas about frameworks to argue that use of the LV equations is in some sense justifiable, but it also appears to be a consequence of his account (and Strevens seems to agree) that explanations appealing to the LV equations are not very deep, considered as standalone explanations. But, at least as a descriptive matter, Potochnik claims, this does not seem to correspond to the judgments or practices of the scientists using these equations, who seem happy to use the LV equations despite the fact that they fail to satisfy the causal contiguity requirement. Potochnik thus challenges this portion of the descriptive adequacy of Strevens’ account. Of course, one might respond that these scientists ought to judge in accord with Strevens’ account, but as noted above, this involves taking the account to have normative implications and not as merely descriptive.
A more general form of this issue arises in connection with “universal” behavior (Batterman 2002). There are a number of cases in which physical and biological systems that are very different from one another in terms of their low-level realizers exhibit similar or identical upper-level behavior (Batterman 2002; Batterman & Rice 2014; Ross 2015). As a well-known example, substances as diverse as ferromagnets and various liquid/gas systems exhibit similar behavior around their critical points (Batterman 2000, 2002). Renormalization techniques are often thought to explain this commonality in behavior, but they do so precisely by showing that the physical details of these systems do not matter for (are irrelevant to) the aspects of their upper-level behavior of interest. The features of these systems that are relevant to their behavior have to do with their dimensionality and symmetry properties among others and this is revealed by the renormalization group analysis (RGA) (Batterman 2010b). One interesting question is whether we can think of that analysis as an instance of Strevens’ kairetic procedure. On the one hand the RGA can certainly be viewed as an abstraction procedure that discards non-difference-making factors. On the other hand, it is perhaps not so clear the RGA respects the cohesiveness requirements that Strevens proposes since the upshot is that systems that are very different at the level of fundamental physics are given a common explanation. That is, the RGA does not seem to work by showing (at least in any obvious way) that the systems to which it applies are contiguous with respect to the underlying physics.[9]
Another related issue is this: a number of philosophers claim that the RGA provides a non-causal explanation (Batterman 2002, 2010a; Reutlinger 2014). As we have seen, Strevens denies that there are non-causal explanations in his extended sense of “causal” but, in addition, if it is thought the RGA implements Strevens’ abstraction procedure, this raises the question of whether (contrary to Strevens’ expectations) this procedure can take causal information as input and yield a non-causal explanation as output. A contrary view, which may be Strevens’, is that as long as the explanation is the result of applying the kairetic procedure to causal input, that result must be causal.
The issue that we have been addressing so far has to do with whether causal contiguity is a defensible requirement to impose on upper-level explanations. There is also a related question – assuming that the requirement is defensible, how can we tell whether it is satisfied? The contiguity requirement as well as the whole abstraction procedure with which it is associated is characterized with reference to fundamental physics but, as we have noted, users of upper-level explanations usually have little or no knowledge of how to connect these with the underlying physics. If Strevens’ model is to be applicable to the assessment of upper-level explanations it must be possible to tell, from the vantage point of those explanations and the available information that surrounds their use, whether they satisfy the contiguity and other requirements but without knowing in detail how they connect to the underlying physics. Strevens clearly thinks this is possible (as he should, given his views) and in some cases this seems plausible. For example, it seems fairly plausible, as we take Strevens to assume, that predator/prey pairs consisting of lions and zebras are disparate from pairs consisting of spiders and house flies from the point of view of the underlying physics and thus constitute heterogeneous realizers of the LV equations.[10] On the other hand, in a case of pre-emption in which Billy’s rock shatters a bottle very shortly before Suzy’s rock arrives at the same space, Strevens seems committed to the claim that these two causal processes are non-contiguous – indeed he needs this result to avoid counting Suzy’s throw as a cause of the shattering[11] (Non-contiguity must hold even if the throws involve rocks with the same mass and velocity following very similar trajectories, differing only slightly in their timing.) In other examples, Strevens claims that airfoils of different flexibility and different materials satisfy the contiguity constraint, as do different molecular scattering processes in gases – apparently this is so even if the latter are governed by rather different potential functions (as they sometimes are) (Strevens 2008: 165–6). The issue here is not that these judgments are obviously wrong but rather that one would like to have a more systematic and principled story about the basis on which they are to be made.
That said, we think that Strevens has put his finger on an important issue that deserves more philosophical attention. This is that there is something explanatorily puzzling or incomplete about a stable upper-level generalization that appears to have very disparate realizers: one naturally wants a further explanation of how this comes about – one that does not leave it as a kind of unexplained coincidence that this uniformity of behavior occurs.[12] The RGA purports to do this for certain aspects of behavior around critical points and it does not seem unreasonable to hope for accounts (perhaps involving some apparatus very different from the RGA) for other cases. What is less clear is whether such an explanation will always appeal to causal contiguity at the level of fundamental physics – for example in the case of the RGA the relevant factors (and where causal contiguity appears to obtain) are relatively abstract and high-level, although certainly “physical”.
## 3. Interventionist Theories
Interventionist theories are intended both as theories of causation and of causal explanation. Here we provide only a very quick overview of the former, referring readers to the entry causation and manipulability for more detailed discussion of the former and instead focus on causal explanation. Consider a causal claim (generalization) of the form
(G)
C causes E
where “C” and “E” are variables – that is, they refer to properties or quantities that can take at least two values. Examples are “forces cause accelerations” and “Smoking causes lung cancer”. According to interventionist accounts (G) is true if and only if there is a possible intervention I such that if I were to change the value of C, the value of E or the probability distribution of E would change (Woodward 2003). The notion of an intervention is described in more detail in the causation and manipulability entry, but the basic idea is that this is an unconfounded experimental manipulation of C that changes E, if at all, via a route that goes through C and not in any other way. Counterfactuals that describe would happen if an intervention were to be performed are called interventionist counterfactuals. A randomized experiment provides one paradigm of an intervention.
Causal explanations can take several different forms within an interventionist framework[13] – for instance, a causal explanation of some explanandum $$E =e$$ requires:
(3.1)
Specification of a true causal generalization $$E= f(C)$$ – that is, some set of values of $$C$$ is mapped into values of $$E$$ by $$f$$ – meeting the interventionist criterion for causation described above,
as well as
(3.2)
One or more initial conditions $$C=c$$ ($$C$$ being the independent variable or variables that figure in (3.1)) such that $$E$$ is derivable from (3.1) and (3.2)
and also meeting the condition
(3.3)
When combined with other initial conditions (3.1) tells us how the value e of E would change under changes in the initial conditions in specified in (3.2).
By meeting these conditions (and especially in virtue of satisfying (3.3)) an explanation answers what Woodward (2003) calls “what-if-things-had-been-different questions” (w-questions) about E – it tells us how E would have been different under changes in the values of the C variable from the value specified in (3.2).
As an example, consider an explanation of why the strength (E) of the electrical field created by a long straight wire along which the charge is uniformly distributed is described by $$E= \lambda/2 \pi r \epsilon_{o}$$ where $$\lambda$$ is the charge density and $$r$$ is the distance from the wire. An explanation of this can be constructed by appealing to Coulomb’s law (playing the role of (3.1) above) in conjunction with information about the shape of the wire and the charge distribution along it ((3.2) above). This information allows for the derivation of $$E= \lambda/2 \pi r \epsilon_{o}$$ but it also can be used to provide answers to a number of other w-questions. For example, Coulomb’s law and a similar modeling strategy can be used to answer questions about what the field would be if the wire had a different shape (e.g., if twisted to form a loop) or if it was somehow flattened into a plane or deformed into a sphere.
The condition that the explanans answer a range of w-questions is intended to capture the requirement that the explanans must be explanatorily relevant to the explanandum. That is, factors having to do with the charge density and the shape of the conductor are explanatorily relevant to the field intensity because changes in these factors would lead to changes in the field intensity. Other factors such as the color of the conductor are irrelevant and should be omitted from the explanation because changes in them will not lead to changes in the field intensity. As an additional illustration, consider Salmon’s (1971a: 34) example of a purported explanation of (F) a male’s failure to get pregnant that appeals to his taking birth control pills (B). Intuitively (B) is explanatorily irrelevant to (F). The interventionist model captures this by observing that B fails to satisfy the what-if-things-had-been-different requirement with respect to F: F would not change if B were to change. (Note the contrast with the rather different way in which the kairetic model captures explanatory relevance.)
Another key idea of the interventionist model is the notion of invariance of a causal generalization (Woodward & Hitchcock 2003). Consider again a generalization (G) relating $$C$$ to $$E$$, $$E= f(C)$$. As we have seen, for (G) to describe a causal relationship at all it must at least be the case that (G) correctly tells how E would change under at least some interventions on C. However, causal generalizations can vary according to the range of interventions over which this is true. It might be that (G) correctly describes how E would change under some substantial range R of interventions that set C to different values or this might instead be true only for some restricted range of interventions on C. The interventions on C over which (G) continues to hold are the interventions over which (G) is invariant. As an illustration consider a type of spring for which the restoring force F under extensions X is correctly described by Hooke’s law:
(3.4)
$$F=-kX$$
for some range R of interventions on X. Extending the spring too much will cause it to break so that its behavior will no longer be described by Hooke’s law. (3.4) is invariant under interventions in R but not so for interventions outside of R. (3.4) is, intuitively, invariant only under a somewhat narrow range of interventions. Contrast (3.4) with the gravitational inverse square law:
(3.5)
$$F= Gm_{1}m_{2}/r^{2}$$.
(3.5) is invariant under a rather wide range of interventions that set $$m_1,$$ $$m_2,$$ and $$r$$ to different values but there are also values for these variables for which (3.5) fails to hold – e.g., values at which general relativistic effects become important. Moreover, invariance under interventions is just one variety of invariance. One may also talk about the invariance of a generalization under many other sorts of changes – for example, changes in background conditions, understood as conditions that are not explicitly included in the generalization itself. As an illustration, the causal connection between smoking and lung cancer holds for subjects with different diets, in different environmental conditions, with different demographic characteristics and so on.[14] However, as explained below, it is invariance under interventions that is most crucial to evaluating whether an explanation is good or deep within the interventionist framework.
Given the account of causal explanation above it follows that for a generalization to figure in a causal explanation it must be invariant under at least some interventions. As a general rule a generalization that is invariant under a wider range of interventions and other changes will be such that it can be used to answer a wider range of w-questions. (See section 4 below.) In this respect such a generalization might be regarded as having superior explanatory credentials – it at least explains more than generalizations with a narrower range of invariance. Generalizations that are invariant under a very wide range of interventions and that have the sort of mathematical formulation that allows for precise predictions are those that we tend to regard as laws of nature. Generalizations that have a narrower range of invariance like Hooke’s “law” capture causal information but are not plausible candidates for laws of nature. An interventionist model of form (3.1–3.3) above thus requires generalizations with some degree of invariance or relationships that support interventionist counterfactuals, but it does not require laws. In this respect, like the other models considered in this entry, it departs from the DN model which does require laws for successful explanation (see the entry on scientific explanation).
Turning now to criticisms of the interventionist model, some of these are also criticisms of interventionist accounts of causation. Several of these (and particularly the delicate question of what it means for an intervention to be “possible”) are addressed if not resolved in the causation and manipulability entry.
Another criticism, not addressed in the above entry, concerns the “truth makers” or “grounds” for the interventionist counterfactuals that figure in causal explanation. Many philosophers hold that it is necessary to provide a metaphysical account of some kind for these. There are a variety of different proposals – perhaps interventionist counterfactuals or causal claims more generally are made true by “powers” or “dispositions”. Perhaps instead such counterfactuals are grounded in laws of nature, with the latter being understood in terms of some metaphysical framework, as in the Best Systems Analysis. For the most part interventionists, have declined to provide truth conditions of this sort and this has struck some metaphysically minded philosophers as a serious omission. One response is that while it certainly makes sense to ask for deeper explanations of why various interventionist counterfactuals hold, the only explanation that is needed is an ordinary scientific explanation in terms of some deeper theory, rather than any kind of distinctively “metaphysical” explanation (Woodward 2017b). For example, one might explain why the interventionist counterfactual “if I were to drop this bottle it will fall to the ground” is true by appealing to Newtonian gravitational theory and “grounding” it in this way. (There is also the task of providing a semantics for interventionist counterfactuals and here there have been a variety of proposals – see, e.g., Briggs 2012. But again, this needn’t take the form of providing metaphysical grounding.) This response raises the question of whether in addition to ordinary scientific explanations there are metaphysical explanations (of counterfactuals, laws and so on) that it is the task of philosophy to provide – a very large topic that is beyond the scope of this entry.
Yet another criticism (pressed by Franklin-Hall 2016 and Weslake 2010) is that the w-condition implies that explanations at the lowest level of detail are always superior to explanations employing upper-level variables – the argument being that lower-level explanations will always answer more w-questions than upper-level explanations. (But see Woodward (2021) for further discussion.)
## 4. Explanatory Depth
Presumably all models of causal explanation (and certainly all of the models considered above) agree that a causal explanation involves the assembly of causal information that is relevant to the explanandum of interest, although different models may disagree about how to understand causation, causal relevance, and exactly what causal information is needed for explanation. There is also widespread agreement (at least among the models considered above) that causal explanations can differ in how deep or good they are. Capturing what is involved in variations in depth is thus an important task for a theory of causal explanation (or for that matter, for any theory of explanation, causal or non-causal). Unsurprisingly different treatments of causal explanation provide different accounts of what explanatory depth consists in. One common idea is that explanations that drill down (provide information) about lower-level realizing detail are (to that extent) better – this is taken to be one dimension of depth even if not the only one.
This idea is discussed by Sober (1999) in the context of reduction, multiple realizability, and causal explanations in biology. Sober suggests that lower-level details provide objectively superior explanations compared to higher-level ones and he supports this in three main ways. First, he suggests that for any explanatory target, lower-level details can always be included without detracting from an explanation. The worst offense committed by this extra detail is that it “explains too much,” while the same cannot be said for higher-level detail (Sober 1999: 547). Second, Sober claims that lower-level details do the “work” in producing higher-level phenomena and that this justifies their privilege or priority in explanations. A similar view is expressed by Waters, who claims that higher-level detail, while more general, provides “shallow explanations” compared to the “deeper accounts” provided by lower-level detail (1990: 131). A third reason is that physics has a kind of “causal completeness” that other sciences do not have. It is argued that this causal completeness provides an objective measure of explanatory strength, in contrast to the more “subjective” measures sometimes invoked in defenses of the explanatory credentials of upper level-sciences. As Sober (1999: 561) puts it,
illumination is to some degree in the eye of the beholder; however, the sense in which physics can provide complete explanations is supposed to be perfectly objective.
Furthermore,
if singular occurrences can be explained by citing their causes, then the causal completeness of physics [ensures] that physics has a variety of explanatory completeness that other sciences do not possess. (1999: 562)
Cases where some type-level effect (e.g., a disease) has a shared causal etiology at higher-levels, but where this etiology is multiply-realized at lower ones present challenges for such views (Ross 2020). In Sober’s example, “smoking causes lung cancer” is a higher-level (macro) causal relationship. He suggests that lower-level realizers of smoking (distinct carcinogens) provide deeper explanations of this outcome. One problem with this claim is that any single lower-level carcinogen only “makes a difference to” and explains a narrow subset of all cases of the disease. By contrast, the higher-level causal factor “smoking” makes a difference to all (or most) cases of this disease. This is reflected in the fact that biomedical researchers and nonexperts appeal to smoking as the cause of lung cancer and explicitly target smoking cessation in efforts to control and prevent this disease. This suggests that there can be drawbacks to including too much lower-level detail.
The kairetic theory also incorporates, in some respects, the idea that explanatory depth is connected to tracking lower-level detail. This is reflected in the requirement that deeper explanations are those that are cohesive with respect to fundamental physics – at the very least we will be in a better position to see that this requirement is satisfied when there is supporting information about low-level realizers.[15] On the other hand, as we have seen, the kairetic abstraction procedure taken in itself pushes away from the inclusion of specific lower-level detail in the direction of greater generality which, in some form or other, is also regarded by most as a desirable feature in explanations, the result being a trade-off between these two desiderata. The role of lower-level detail is somewhat different in mechanistic models since in typical formulations generality per se is not given independent weight, and depth is associated with the provision of more rather than less relevant detail. Of course a great deal depends on what is meant by “relevant detail”. As noted above, this issue is taken up by Craver in several papers, including most recently, Craver and Kaplan (2020) who discuss what they call “norms of completeness” for mechanistic explanations, the idea being that there needs to be some “stopping point” at which a mechanistic explanation is complete in the sense that no further detail needs to be provided. Clearly, whatever “relevant detail” in this connection means it cannot mean all factors any variation in which would make a difference to some feature of the phenomenon P which is the explanatory target. After all, in a molecular level explanation of some P, variations at the quantum mechanical level – say in the potential functions governing the behavior of individual atoms will often make some difference to P, thus requiring (on this understanding of relevance) the addition of this information. Typically, however, such an explanation is taken by mechanists to be complete just at the molecular level – no need to drill down further. Similarly, from a mechanistic point of view an explanation T of the behavior of a gas in terms of thermodynamic variables like pressure and temperature is presumably less than fully adequate since the gas laws are regarded by some if not most mechanists as merely “phenomenological” and not as describing a mechanism. A statistical mechanical explanation (SM) of the behavior of the gas is better qua mechanistic explanation but ordinarily such explanations don’t advert to, say, the details of the potentials (DP) governing molecular interactions, even though variations in these would make some difference to some aspects of the behavior of the gas. The problem is thus to describe a norm of completeness that allows one to say that SM is superior to T without requiring DP rather than SM. Craver and Kaplan’s discussion (2020) is complex and we will not try to summarize it further here except to say that it does try to find this happy medium of capturing how a norm of completeness can be met, despite its being legitimate to omit some detail.
A closely related issue is this: fine-grained details can be relevant to an explanandum in the sense that variations in those details may make a difference to the explanandum but it can also be the case that those details sometimes can be “screened off” from or rendered conditionally irrelevant to this explanandum (or approximately so) by other, more coarse grained variables that provide less detail, as described in Woodward 2021. For example, thermodynamic variables can approximately screen off statistical mechanical variables from one another. In such a case is it legitimate to omit (do norms about completeness permit omitting) the more fine-grained details as long as the more coarse-grained but screening off detail is included?
Interventionist accounts, at least in the form described by Woodward (2003), Hitchcock and Woodward (2003) offer a somewhat different treatment of explanatory depth. Some candidate explanations will answer no w-questions and thus fail to be explanatory at all. Above this threshold explanations may differ in degree of goodness or depth, depending on the extent to which they provide more rather than less information relevant to answering w-questions about the explanandum – and thus more information about what the explanandum depends on. For example, an explanation of the behavior of a body falling near the earth’s surface in terms of Galileo’s law $$v=gt$$ is less deep than an explanation in terms of the Newtonian law of gravitation since the latter makes explicit how the rate of fall depends on the mass of the earth and the distance of the body above the earth’s surface. That is, the Newtonian explanation provides answers to questions about how the velocity of the fall would have been different if the mass of the earth had been different, if the body was falling some substantial distance away from the earth’s surface and so on, thus answering more w-questions than the explanation appealing to Galileo’s law.
This account associates generality with explanatory depth but this connection holds only for a particular kind of generality. Consider the conjunction of Galileo’s law and Boyle’s law. In one obvious sense, this conjunction is more general than either Galileo’s law or Boyle’s law taken alone – more systems will satisfy either the antecedent of Galileo’s law or the antecedent of Boyle’s law than one of these generalizations alone. On the other hand, given an explanandum having to do with the pressure P exerted by a particular gas, the conjunctive law will tell us no more about what P depends on than Boyle’s law by itself does. In other words, the addition of Galileo’s law does not allow us to answer any additional w-questions about the pressure than are answered by Boyle’s law alone. For this reason, this version of interventionism judges that the conjunctive law does not provide a deeper explanation of P than Boyle’s law despite the conjunctive law being in one sense more general (Hitchcock & Woodward 2003).
To develop this idea in a bit more detail, let us say that the scope of a generalization has to do with the number of different systems or kinds of systems to which the generalization applies (in the sense that the systems satisfy the antecedent and consequents of the generalization). Then the interventionist analysis claims that greater scope per se does not contribute to explanatory depth. The conjunction of Galileo’s and Boyle’s law has greater scope than either law alone, but it does not provide deeper explanations.
As another, perhaps more controversial, illustration consider a set of generalizations N1 that successfully explain (by interventionist criteria) the behavior of a kind of neural circuit found only in a certain kind K of animal. Would the explanatory credentials of N1 or the depth of the explanations it provides be improved if this kind of neural circuit was instead found in many different kinds of animals or if N1 had many more instances? According to the interventionist treatment of depth under consideration, the answer to this question is “no” (Woodward 2003: 367). Such an extension of the application of N1 is a mere increase in scope. Learning that N1 applies to other kinds of animals does not tell us anything more about what the behavior of the original circuit depends on than if N1 applied just to a single kind of animal.
It is interesting that philosophical discussions of the explanatory credentials of various generalizations often assume (perhaps tacitly) that greater scope (or even greater potential scope in the sense that there are possible – perhaps merely metaphysically possible – but not actual systems to which the generalization would apply) per se contributes to explanatory goodness. For example, Fodor and many others argue for the explanatory value of folk psychology on the grounds that its generalizations apply not just to humans but would apply to other systems with the appropriate structure were these to exist (perhaps certain AI systems, Martians if appropriately similar to humans etc.) (Fodor 1981: 8–9). The interventionist treatment of depth denies there is any reason to think the explanatory value of folk psychology would be better in the circumstances imagined above than if it applied only to humans. As another illustration, Weslake (2010) argues that upper-level generalizations can provide better or deeper explanations of the same explananda than lower-level generalizations if there are physically impossible [but metaphysically possible] systems to which the upper-level explanation applies but to which the lower-level explanation does not (2010: 287), the reason being that in such cases the upper- level explanation is more general in the sense of applying to a wider variety of systems. Suppose for example, that for some systems governed by the laws of thermodynamics, the underlying micro theory is Newtonian mechanics and for other “possible” or actual systems governed by the same thermodynamic laws, the correct underlying micro-theory is quite different. Then, according to Weslake, thermodynamics provides a deeper explanation than the either of the two micro-theories. This is also an argument that identifies greater depth with greater scope. The underlying intuition about depth here is, so to speak, the opposite of Strevens’ since he would presumably draw the conclusion that in this scenario the generalizations of thermodynamics would lack causal cohesion if the different realizing microsystems were actual.
This section has focused on recent discussion of the roles played by the provision of more underlying detail, and generality (in several interpretations of that notion) in assessments of the depth of causal explanation. It is arguable that there are a number of other dimensions of depth that we do not discuss – readers are referred to Glymour (1980), Wigner (1967), Woodward (2010), Deutsch (2011) among many others.
## 5. Non-causal and Mathematical Explanation
We noted above that there has been considerable recent interest in the question of whether there are non-causal explanations (of the “why” variety) or whether instead all explanations are causal. Although this entry does not discuss non-causal explanations in detail, this issue raises the question of whether there is anything general that might be said about what makes an explanation “causal” as opposed to “non-causal”. In what follows we review some proposals about the causal/non-causal contrast, including ideas that abstract somewhat from the details of the theories described in previous sections.
We will follow the philosophical literature on this topic by focusing on candidate explanations that target empirical explananda within empirical science but (it is claimed) explain these non-causally. These contrast with explanations within mathematics, as when some mathematical proofs are regarded as explanatory (of mathematical facts). Accounts of non-causal explanation in empirical science typically focus on explanatory factors that seem “mathematical”, that abstract from lower-level causal details, and/or that are related to the explanatory target via dependency relations that are (in some sense) non-empirical, even though the explanatory target appears to be an empirical claim. A common suggestion is that explanations exhibiting one or more of these features, qualify as non-causal. Purported examples include appeals to mathematical facts to explain various traits in biological systems, such as the prime-number life cycles of cicadas, the hexagonal-shape of the bee’s honeycomb, and the fact that seeds on a sunflower head are described by the golden angle (Baker 2005; Lyon & Colyvan 2008; Lyon 2012). An additional illustration is Lange’s claim (e.g., 2013: 488) that one can explain why 23 strawberries cannot be evenly divided among three children by appealing to the mathematical fact that 23 is not evenly divisible by three. It is claimed that in these cases, explaining the outcome of interest requires appealing to mathematical relationships, which are distinct from causal relationships, in the sense that the former are non-contingent and part of some mathematical theory (e.g., arithmetic, geometry, graph theory, calculus) or a consequence of some mathematical axiom system.
A closely related idea is that in addition to appealing to mathematical relationships, non-causal explanations abstract from lower-level detail, with the implication that although these details may be causal, they are unnecessary for the explanation which is consequently taken to be non-causal. The question of whether it is possible to traverse each bridge in the city of Königsberg exactly once (hereafter just “traverse”) is a much-discussed example. Euler provided a mathematical proof that whether such traversability is possible depends on higher-level topological or graph-theoretical properties concerning the connectivity of the bridges, as opposed to any lower-level causal details of the system (Euler 1736 [1956]; Pincock 2012). This explanatory pattern is similar to other topological or network explanations in the literature, which explain despite abstracting from lower-level causal detail (Huneman 2012; Kostic 2020; Ross 2021b). Other candidates for non-causal explanations are minimal model explanations, in which the removal of at least some or perhaps all causal detail is used to explain why systems which differ microphysically all exhibit the same behavior in some respects (Batterman 2002; Chirimuuta 2014; Ross 2015; and the entry on models in science).
Still other accounts (not necessarily inconsistent with those described above) attempt to characterize some non-causal explanations in terms of the absence of other features (besides those described above). Woodward (2018) discusses two types of cases.
(5.1)
Cases in which the factors cited in the explanans are not possible targets of physical interventions, although we can still ask what would be the case if those factors were different.
(5.2)
Cases in which, although the factors in the explanans are possible targets of interventions, the dependency relation between explanans and explanandum is “mathematical” rather than contingent.
An example of (5.1) is a purported explanation relating the possibility of stable planetary orbits to the dimensionality of space – given natural assumptions, stable orbits are possible in a three-dimensional space but not possible in a space of dimensionality greater than three, so that the possibility of stable orbits in this sense seems to depend on the dimensionality of space. (For discussion see Ehrenfest 1917; Büchel 1963 [1969]; Callendar 2005). Assuming it is not possible to intervene to change the dimensionality of space, this explanation (if that is what it is) is treated as non-causal within an interventionist framework because of this impossibility. In other words, the distinction between explanations that appeal to factors that are targets of possible interventions and those that appeal to factors that are not targets of possible interventions is taken to mark one dividing line between causal and non-causal explanations.
In the second set of cases (5.2), there are factors cited in the explanans that can be changed under interventions but the relationship between this property and the explanandum is non-contingent and “mathematical”. For example, it is certainly possible to intervene to change the configuration of bridges in Königsberg and in this way to change their traversability but the relation between the bridge configuration and their traversability is, as we have seen, non-contingent. Many of the examples mentioned earlier – the cicada, honeybee, and sunflower cases – are similar. In these cases, the non-contingent character of the dependency relation between explanans and explanandum is claimed to mark off these explanations as non-causal.
A feature of many of the candidates for non-causal explanation discussed above (and arguably another consideration that distinguishes causal from non-causal explanations) is that the non-causal explanations often seem to explain why some outcome is possible or impossible (e.g., why stable orbits are possible or impossible in spaces of different dimensions, why it is possible or not to traverse various configurations of bridges). By contrast it seems characteristic of causal explanations that they are concerned with a range of outcomes all of which are taken to be possible and instead explain why one such outcome in contrast to an alternative is realized (why an electric field has a certain strength rather than some alternative strength.)
While many have taken the above examples to represent clear cases of non-causal, mathematical explanation, others have argued that these explanations remain causal through-and-through. One example of this expansive position about causal explanation is Strevens (2018). According to Strevens, the Königsberg and other examples are cases in which mathematics plays a merely representational role, for example the role of representing difference-makers that dictate the movement of causal processes in the world. Strevens refers to these as “non-tracking” explanations, which identify limitations on causal processes that can explain their final outcome, but not the exact path taken to them (Strevens 2018: 112). For Strevens the topological structure represented in the Königsberg’s case captures information about causal structure or the web of causal influence – in this way the information relevant to the explanation, although abstract, is claimed to be causal. While this argument is suggestive, one open question is how the kairetic account can capture the fact that some of these cases involve explanations of impossibilities, where the source of the impossibility is not obviously “structural” (Lange 2013, 2016). For example, the impossibility of evenly dividing 23 by 3 does not appear to be a consequence of the way in which a structure influences some causal process.[16]
In addition to the examples and considerations just described, the philosophical literature contains many other proposed contrasts between causal and non-causal explanations, with accompanying claims about how to classify particular cases. For example, Sober (1983) claims that “equilibrium explanations” are non-causal. These are explanations in which an outcome is explained by showing that, because it is an equilibrium (or better, a unique equilibrium) , any one of a large number of different more specific processes would have led to that outcome. As an illustration, for sexually reproducing populations meeting certain additional conditions (see below), natural selection will produce an equilibrium in which there are equal numbers of males and females, although the detailed paths by which this outcome is produced (which conception events lead to males or females) will vary on different occasions. The underlying intuition here is that causal explanations are those that track specific trajectories or concrete processes, while equilibrium explanations do not do this. By contrast the kairetic theory treats at least some equilibrium explanations as causal in an extended sense (Strevens 2008: 267). Interventionist accounts at least in form described in Woodward (2003) also take equilibrium explanations to be causal to the extent that information is provided about what the equilibrium itself depends on. (That is, the interventionist framework takes the explanandum to be why this equilibrium rather than some alternative equilibrium obtains.) For example, the sex ratio equilibrium depends on such factors as the amount of parental investment required to produce each sex. Differences in required investment can lead to equilibria in which there are unequal numbers of males and females. On interventionist accounts, parental investment is thus among the causes of the sex ratio because it makes a difference for which equilibrium is realized. Interventionist accounts are able to reach this conclusion because they treat relatively “abstract” factors like parental investment as causes as long as interventions on these are systematically associated with associated with changes in outcomes. Thus, in contrast to some of the accounts described above, interventionism does not regard the abstractness per se of an explanatory factor as a bar to interpreting it as causal.
There has also been considerable discussion of whether computational explanations of the sort found in cognitive psychology and cognitive neuroscience that relate inputs to outputs via computations are causal or mechanistic. Many advocates (Piccinini 2006; Piccinini & Craver 2011) of mechanistic models of explanation have regarded such explanations as at best mechanism sketches, since they say little or nothing about realizing (e.g., neurobiological) detail. Since these writers tend to treat “mechanistic explanation”, “causal explanation” and even “explanation” as co-extensional, at least in the biomedical sciences, they seem to leave no room for a notion of non-causal explanation. By contrast computational explanations count as causal by interventionist lights as long as they correctly describe how outputs vary under interventions on inputs (Rescorla 2014). But other analyses of computational models suggest that they are similar to non-causal forms of explanation (Chirimuuta 2014, 2018).
Besides the authors discussed above, there is a great deal of additional recent work related to causal explanation that we lack the space to discuss. For additional work on the role of abstraction and idealization in causal explanation (and whether the presence of various sorts of abstraction and idealization in an explanation implies that it is non-causal) see Janssen and Saatsi (2019), Reutlinger and Andersen (2016), Blanchard (2020), Rice (2021), and Pincock (2022). Another set of issues that has received a great deal of recent attention concerns causal explanation in contexts in which different “levels” are present (Craver & Bechtel 2007; Baumgartner 2010; Woodward 2020) This literature addresses questions of the following sort. Can there be “upper-level” causation at all or does all causal action occur at some lower, microphysical level, with upper-level variables being casually inert? Can there be “cross-level” causation – e.g., “downward” causation from upper to lower levels? Finally, in addition to the work on explanatory depth discussed in Section 4, there has been a substantial amount of recent work on distinctions among different sorts of causal claims (Woodward 2010; Ross 2021a; Ross & Woodward 2022) and on what makes some causes more explanatorily significant than others (e.g., Potochnik 2015).
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http://math.stackexchange.com/questions/181898/is-there-a-simple-proof-of-the-isoperimetric-theorem-for-squares?answertab=votes | # Is there a “simple” proof of the isoperimetric theorem for squares?
"Simple" means that it doesn't use any integral or multivariable calculus concepts.
A friend of mine who's taking a differential calculus course came up with the problem
Prove that among all the quadrilaterals with a given perimeter, the one with the biggest area is the square.
I solved the problem with Lagrange multipliers, using $2h + 2b$ as the function and $hb = A$ as the constraint. But I'm the one who took the multivariable calculus course, not him.
So I'd like to know if there's a way of proving this theorem using differential calculus concepts, or even geometry and trigonometry.
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Isn't the problem you solved different from the one you pose? You solved a maximization of the perimeter given a fixed area. – Jose27 Aug 13 '12 at 1:46
Well, $A$ is an arbitrary constant and $h$ and $b$ are variables. I got $h = b$ as the only solution for this maximization, shouldn't that be enough for proving it? – user1002327 Aug 13 '12 at 1:51
See this. The isoperimetric theorem is discussed a bit later, after the inequality shown on that page. – Timmy Turner Aug 13 '12 at 1:52
@user1002327: Yes, but you're solving a different problem: You're maximizing perimeter with a given area as constrain. On the other hand you're asking for maximization of the area given a perimeter. – Jose27 Aug 13 '12 at 1:57
Oh, you're right. – user1002327 Aug 13 '12 at 1:59
In the case of rectangles, here's a solution of the dual problem: find the rectangle of smallest perimeter for a given area. The shapes should be the same.
Just complete the square (if you can pardon the expression). The width is $w$; the height is $A/w$ (where $A$ is the area). So the semi-circumference is $$w + \frac A w = \left(w - 2\sqrt{A}+ \frac A w\right) + 2\sqrt{A} = \left(\sqrt{w} - \sqrt{\frac{A}{w}}\right)^2 + 2\sqrt{A}.$$ This is as small as possible when the expression that gets squared is $0$. So that $=0$ when $w=\text{what?}$
Later edit: Now let's try it more directly. The perimeter is $4\ell$. You have a rectangle with two opposite sides of length $k$ and and two of length $2\ell-k$. The area is \begin{align} A & = k(2\ell-k) = -k^2 + 2k\ell = -\Big(k^2 - 2k\ell\Big) = -\Big(k^2 -2k\ell + \ell^2\Big) +\ell^2 \\[8pt] & = -\Big(k-\ell\Big)^2 + \ell^2. \end{align} This is as big as possible when $k=\ell$, so you have a square.
We still have the case of non-rectangles to deal with.
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The second proof is very simple, looks like we can use that. And I don't think they're going to deal with the other quadrilaterals in a differential calculus course for engineers, so I'm marking your answer as the correct one. Thanks. – user1002327 Aug 13 '12 at 2:03
This is essentially the arithmetic-geometric mean (AM-GM) inequality for lists of 2 numbers. http://en.wikipedia.org/wiki/Inequality_of_arithmetic_and_geometric_means#Geometric_interpretation
In higher dimensions, the inequality says that the hypercube has the most volume among all boxes where the sum of length + width + depth + ... is fixed.
The wiki page above has a bunch of proofs, many of which don't use calculus.
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Since you mentioned being interested in a geometric proof, here's one that should be easy to understand (albeit with one sneaky detail swept under the rug). Start with a $w\times h$ rectangle, with $w\gt h$; we'll prove that there's another rectangle of the same perimiter but greater area. Since the area of the rectangle is twice the area of the triangle of base $w$ and height $h$, we can just consider the triangle's area. But now consider adding some small amount $x$ to the height $h$ and subtracting the same amount from the width $w$. This doesn't change the perimeter, since we're just redistributing a small segment, but we can see what it does to the area:
The area of the original triangle with base $w$ and height $h$ is the sum of the pink and green triangles, while the area of the new triangle with base $w-x$ and height $h+x$ is the sum of the pink and blue triangles. But as long as $w-x\gt h+x$, the blue triangle will have a greater area than the green one: they both have the same base ($x$) and the blue one has a greater height. This implies that as long as $w\gt h$, we can increase the area of the triangle (and thus the rectangle) by trading off some amount of width for the same amount of height, and that in turn implies that the maximum area must be achieved by the square.
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I really like this one, I'm very tempted to choose yours as the correct answer. – user1002327 Aug 13 '12 at 22:27
Thank you! As I said, it does have one subtle catch - I don't have a quick, easy geometric proof as to why the height of the blue triangle is larger other than the intuition that the intersection point lies on the 'right' side of the $45^\circ$ bisector through the right angle. An algebraic proof is easy, but loses a lot of the charm of the core proof; still, if you present this one, most students probably won't catch you on it! – Steven Stadnicki Aug 14 '12 at 4:15 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 1, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9035151600837708, "perplexity": 337.99063962674586}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-18/segments/1429246640550.27/warc/CC-MAIN-20150417045720-00249-ip-10-235-10-82.ec2.internal.warc.gz"} |
https://link.springer.com/chapter/10.1007%2F978-3-319-33954-2_28 | # A New Solver for the Minimum Weighted Vertex Cover Problem
• Hong Xu
• T. K. Satish Kumar
• Sven Koenig
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9676)
## Abstract
Given a vertex-weighted graph $$G = \langle V, E \rangle$$, the minimum weighted vertex cover (MWVC) problem is to choose a subset of vertices with minimum total weight such that every edge in the graph has at least one of its endpoints chosen. While there are good solvers for the unweighted version of this NP-hard problem, the weighted version—i.e., the MWVC problem—remains understudied despite its common occurrence in many areas of AI—like combinatorial auctions, weighted constraint satisfaction, and probabilistic reasoning. In this paper, we present a new solver for the MWVC problem based on a novel reformulation to a series of SAT instances using a primal-dual approximation algorithm as a starting point. We show that our SAT-based MWVC solver (SBMS) significantly outperforms other methods.
## Notes
### Acknowledgments
The research at USC was supported by NSF under grant numbers 1409987 and 1319966 and a MURI under grant number N00014-09-1-1031. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the sponsoring organizations, agencies or the U.S. government.
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https://elabs.academy/course/is-lm/The-Investment-Function | The Keynesian cross is a stepping-stone on our path to the IS-LM model. It is useful because it shows how the spending plans of households, firms and the government determine the economy's income. Yet, we have assumed that the level of planned investment $I$ is fixed. We now relax this assumption in our model by introducing a relationship between the interest rate and planned investment:
$I = I(r)$
Because the interest rate is the cost of borrowing to finance investment projects, an increase in the interest rate reduces planned investment. As a result, the investment function slopes downward.
$r$
1.00
0.2511.75 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 3, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6737590432167053, "perplexity": 988.7526122248987}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-13/segments/1552912202433.77/warc/CC-MAIN-20190320150106-20190320172106-00301.warc.gz"} |
https://www.ideals.illinois.edu/handle/2142/22498 | ## Files in this item
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## Description
Title: Solid state nuclear magnetic resonance spectroscopic studies of quadrupolar nuclei in inorganic systems and determination of optical parameters in optical waveguides Author(s): Han, Oc Hee Department / Program: Chemistry Discipline: Chemistry Degree Granting Institution: University of Illinois at Urbana-Champaign Degree: Ph.D. Genre: Dissertation Subject(s): Chemistry, Analytical Chemistry, Inorganic Chemistry, Physical Abstract: The general purpose of my research in this thesis is to apply solid state NMR of quadrupole nuclei to characterize and probe the chemical, structural, physical and electronic properties of materials, such as group III-V semiconductors, AlCl$\sb3\cdot$THF complexes, graphite intercalated with AlCl$\sb3$ (and related systems), and the copper-free high T$\sb{\rm c}$ superconductor (Ba$\sb{0.6}$K$\sb{0.4}$BiO$\sb3$), and related systems. Overall, I have tried to use solid-state NMR to give new information about structure in a variet of interesting and important conducting compounds, especially: semiconductors, superconductors, and metallic intercalation compounds (together with additional studies on appropriate "model" compounds). Issue Date: 1989 Type: Text Language: English URI: http://hdl.handle.net/2142/22498 Rights Information: Copyright 1989 Han, Oc Hee Date Available in IDEALS: 2011-05-07 Identifier in Online Catalog: AAI9010874 OCLC Identifier: (UMI)AAI9010874
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http://www.chennaispeakers.com/2016/09/is-ramkumar-died-of-electric-wire.html | # Is Ramkumar died of electric wire?????
0
Ramkumar who was caught in the case of swathi murder was prisoned in puzhal is found to dead at 18th of this month. He committed suicide by biting teh electric wire passing inside the block where he was put is the information for from.the securities of the prison. There are. Some suspect in the death of the ramkumar said by his family members.
After postmortem somehow we people was eager that will get cleared from the investigation but there are obstacles prevailing still.
Electric wire is embossed in the wall from this suspect arises that how he would have died by biting the wire.
There was a switch box near the place where he is dead. That is not that much easy to bite the wire which is already embossed in the wall. Suppose if he has done that he would have got shock and he would have thrown somewhere due to the radiation.
There’s was no scars in his body so we conclude that he would have not died due to the electric wire shock.
We will come to known there real reason of the death only after CBI investigation and the post mortem report.
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SHARE | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9130332469940186, "perplexity": 2548.117687189837}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-43/segments/1508187824618.72/warc/CC-MAIN-20171021062002-20171021082002-00139.warc.gz"} |
http://mathhelpforum.com/number-theory/172931-prove-sum-all-positive-integers-k-print.html | # Prove the sum of all positive integers k...
• February 28th 2011, 09:09 AM
uberbandgeek6
Prove the sum of all positive integers k...
Prove that the sum of all positive integers k where 1 <= k <= n and gcd(k,n) = 1 is (1/2)n*phi(n).
I don't even know where to begin with this. We've been going over primitive roots in class lately so it probably has something to do with them, but I have no idea where they come into the problem.
• February 28th 2011, 02:16 PM
LoblawsLawBlog
For any n, $\zeta=e^{2\pi i/n}$ is a primitive nth root of unity, and the other primitive roots are exactly the numbers $\zeta^k$, where gcd(k,n)=1. If you picture these on the unit circle and realize that the conjugate of a primitive root is also a primitive root, you can prove it that way.
• February 28th 2011, 06:21 PM
uberbandgeek6
Quote:
Originally Posted by LoblawsLawBlog
For any n, $\zeta=e^{2\pi i/n}$ is a primitive nth root of unity, and the other primitive roots are exactly the numbers $\zeta^k$, where gcd(k,n)=1. If you picture these on the unit circle and realize that the conjugate of a primitive root is also a primitive root, you can prove it that way.
Uh, we didn't learn anything like that in class.
• February 28th 2011, 06:55 PM
LoblawsLawBlog
Ok, I tried to explain it using primitive roots because you said you're learning about them. The same proof will carry over to the group $\mathbb{Z}/n\mathbb{Z}$, since this group is isomorphic to the nth roots of unity. But you might not be doing much with groups if this is a number theory course, even though there's a lot of overlap.
I guess the key facts are that $\varphi(n)$ is the number of positive integers less than n that are relatively prime to n and also that gcd(n,k)=gcd(n,n-k). Does that help?
You could probably also prove this using some facts about $\varphi$ listed on its wikipedia page.
edit: Ah, that explains it- there are two uses of the term primitive root. I thought you meant primitive roots of unity and I had never heard of the other meaning. Still, my second paragraph could still be used.
• February 28th 2011, 07:21 PM
chisigma
Quote:
Originally Posted by uberbandgeek6
Prove that the sum of all positive integers k where 1 <= k <= n and gcd(k,n) = 1 is (1/2)n*phi(n).
I don't even know where to begin with this. We've been going over primitive roots in class lately so it probably has something to do with them, but I have no idea where they come into the problem.
In any case is $\displaystyle \sum_{k=1}^{n-1} k= \frac{n\ (n-1)}{2}$. If n is prime then $\varphi(n)= n-1$ so that $\displaystyle \sum_{k=1}^{n-1} k= \frac{n}{2}\ \varphi(n)$...
Kind regards
$\chi$ $\sigma$
• March 1st 2011, 05:44 AM
uberbandgeek6
@chisigma: I understand what you mean, but I'm not given that n is prime, so I don't see how that would work.
@Loblawslawblog: I don't understand where you are going with the gcd(n, n-k). I get that it is true, but I don't see how that helps.
• March 1st 2011, 06:46 AM
chisigma
Quote:
Originally Posted by uberbandgeek6
@chisigma: I understand what you mean, but I'm not given that n is prime, so I don't see how that would work.
One of Your hypothesis is that $\forall k$ for which $0\le k\le n$ is $\text {gcd} (k,n)=1$ and that means that n is prime...
Kind regards
$\chi$ $\sigma$
• March 1st 2011, 06:57 AM
uberbandgeek6
Quote:
Originally Posted by chisigma
One of Your hypothesis is that $\forall k$ for which $0\le k\le n$ is $\text {gcd} (k,n)=1$ and that means that n is prime...
Kind regards
$\chi$ $\sigma$
Maybe I'm interpreting it wrong, but I think the problem means that it wants the sum of all k's that are relatively prime with n. So if n was not prime (say n = 10), it would be 1+3+7+9 = 20. Then (1/2)(10)phi(10) = 20 as well.
• March 1st 2011, 07:35 AM
LoblawsLawBlog
Quote:
Originally Posted by uberbandgeek6
@Loblawslawblog: I don't understand where you are going with the gcd(n, n-k). I get that it is true, but I don't see how that helps.
Look at your example with n=10. 1 is relatively prime to 10, and so is 10-1=9. Likewise, 3 and 10-3=7 are both relatively prime to 10. Then the sum we're looking for is (1+9)+(3+7)=(4/2)(10).
• March 1st 2011, 10:28 AM
tonio
Quote:
Originally Posted by LoblawsLawBlog
Look at your example with n=10. 1 is relatively prime to 10, and so is 10-1=9. Likewise, 3 and 10-3=7 are both relatively prime to 10. Then the sum we're looking for is (1+9)+(3+7)=(4/2)(10).
The hint, or info, given by LLLB is critical: let
$\Phi(n,k):=\{k\in\mathbb{N}\;;\;1\leq k\leq n\,,\,\,gcd(n,k)=1\}$
1) Prove that $k\in\Phi(n,k)\Longleftrightarrow n-k\in\Phi(n,k)$
2) Thus, we can pair up all the numbers in $\Phi(n,k)$ in pairs $(k,n-k)$ , with
$k\mbox{ and also }n-k\mbox{ in } \Phi(n,k)$
3) Since $|\Phi(n,k)|=\phi(n)$ , there are $\frac{1}{2}\phi(n)$ pairs as above, and
since the sum of each such pair is $n$ we're then done...(Clapping)
Tonio
• March 1st 2011, 07:11 PM
Bruno J.
Quote:
Originally Posted by LoblawsLawBlog
For any n, $\zeta=e^{2\pi i/n}$ is a primitive nth root of unity, and the other primitive roots are exactly the numbers $\zeta^k$, where gcd(k,n)=1. If you picture these on the unit circle and realize that the conjugate of a primitive root is also a primitive root, you can prove it that way.
How can you prove it that way?
• March 2nd 2011, 08:10 AM
LoblawsLawBlog
It's the same proof. A primitive root z^k would correspond to k in Z_n and the pairing (k,n-k) is just the pair z^k and its conjugate. Then the factor of 1/2 comes in because you only need to consider the top half of the unit circle. Add the exponents of the primitive roots and you're done.
So basically there's no reason to go to complex numbers, but I tried to awkwardly jam them in because I thought the OP was learning something similar.
• March 2nd 2011, 08:23 AM
Bruno J.
That's what I thought. There's no reason to talk about primitive roots here. :) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 32, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9033001661300659, "perplexity": 346.55223751029627}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-35/segments/1408500831903.50/warc/CC-MAIN-20140820021351-00086-ip-10-180-136-8.ec2.internal.warc.gz"} |
http://mathhelpforum.com/advanced-algebra/103586-bilinear-maps.html | 1. ## Bilinear Maps
I was told that any bilinear map $B: V\times V\longrightarrow \mathbb{F}$ (where $V$ is an n-dimensional vector space and $\mathbb{F}$ is a field of scalars) can be expressed as $B(u,v)=u^TAv$, where $A$ is an $n\times n$ matrix.
Does this statement require proof, and if so, how can I prove it?
2. Originally Posted by redsoxfan325
I was told that any bilinear map $B: V\longrightarrow \mathbb{F}$ (where $V$ is an n-dimensional vector space and $\mathbb{F}$ is a field of scalars) can be expressed as $B(u,v)=u^TAv$, where $A$ is an $n\times n$ matrix.
Does this statement require proof, and if so, how can I prove it?
A bilinear form on V is a bilinear mapping $B: V \times V \longrightarrow \mathbb{F}$ such that
B(u+u', v) = B(u,v) + B(u',v),
B(u, v+v') = B(u,v) + B(u,v'),
B(tu, v) = B(u, tv) = tB(u,v), where t is a scalar in the field F.
Let u= BX, v=BY, where B = (v_1, v_2, ... , v_n) is a basis of V and X,Y are coordinate vectors.
Then, $B(u, v) = B(\sum_iv_ix_i, \sum_jv_jy_j)$.
Using bilinearity, $B(\sum_iv_ix_i, \sum_jv_jy_j) = \sum_{i,j}x_iy_jB(v_i, v_j)=X^TAY$, where A is $B(v_i, v_j)$.
3. Originally Posted by redsoxfan325
I was told that any bilinear map $B: V\longrightarrow \mathbb{F}$ (where $V$ is an n-dimensional vector space and $\mathbb{F}$ is a field of scalars) can be expressed as $B(u,v)=u^TAv$, where $A$ is an $n\times n$ matrix.
Does this statement require proof, and if so, how can I prove it?
that $B$ is actually from $V \times V$ to $\mathbb{F}.$ also $u^TAv$ has no meaning unless you fix a basis $\mathcal{B}=\{e_1, \cdots , e_n \}$ for $V$ and then by $u,v$ we'll mean $[u], \ [v],$ the coordinate vectors of $u,v$ with respect to
the basis $\mathcal{B}.$ anyway, the proof is quite easy: define the matrix $A=[a_{ij}]$ by $a_{ij}=B(e_i,e_j).$ now $[e_k], \ 1 \leq k \leq n,$ is an $n \times 1$ vector with $1$ in its $k$-th row and $0$ is in other rows. it's easy to see
that $[e_i]^T A [e_j]=a_{ij}=B(e_i,e_j).$ finally if $u=\sum_i b_ie_i, \ v=\sum_i c_ie_i,$ then using bilinearity of $B$ we get: $B(u,v)=\sum_{i,j} b_ic_j B(e_i,e_j)=\sum_{i,j}b_ic_j[e_i]^T A [e_j]=(\sum_i b_i[e_i]^T)A (\sum_j c_j[e_j] )=[u]^TA[v].$ | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 43, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9921922087669373, "perplexity": 173.34968745972466}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-17/segments/1492917121267.21/warc/CC-MAIN-20170423031201-00077-ip-10-145-167-34.ec2.internal.warc.gz"} |
http://www.ck12.org/measurement/Comparison-of-Metric-Measurements/web/user:13IntK/Measures/r1/ | <meta http-equiv="refresh" content="1; url=/nojavascript/">
# Comparison of Metric Measurements
## Use <, > and/or equal to when comparing metric measurements.
%
Progress
Practice Comparison of Metric Measurements
Progress
%
This interactive game teaches the metric system and how to convert both to and from metric units. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8220025300979614, "perplexity": 10988.828043523821}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-22/segments/1432207928078.25/warc/CC-MAIN-20150521113208-00297-ip-10-180-206-219.ec2.internal.warc.gz"} |
https://www.jswconline.org/highwire/markup/5476/expansion?width=1000&height=500&iframe=true&postprocessors=highwire_tables%2Chighwire_reclass%2Chighwire_figures%2Chighwire_math%2Chighwire_inline_linked_media%2Chighwire_embed | Table 5
Parameters for linear regression for concentration and load between dissolved reactive phosphorus (DRP as dependent variable) and total P (TP as independent variable) by treatment. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.879038393497467, "perplexity": 10922.140950529016}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-49/segments/1637964363229.84/warc/CC-MAIN-20211206012231-20211206042231-00584.warc.gz"} |
https://human.libretexts.org/Courses/Community_College_of_Allegheny_County/Book%3A_A_Guide_to_Rhetoric_Genre_and_Success_in_First-Year_Writing_(Gagich_and_Zickel)/09%3A_Reading_about_Writing/9.07%3A_APA_Citation | # 9.7: APA Citation
$$\newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} }$$ $$\newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}}$$$$\newcommand{\id}{\mathrm{id}}$$ $$\newcommand{\Span}{\mathrm{span}}$$ $$\newcommand{\kernel}{\mathrm{null}\,}$$ $$\newcommand{\range}{\mathrm{range}\,}$$ $$\newcommand{\RealPart}{\mathrm{Re}}$$ $$\newcommand{\ImaginaryPart}{\mathrm{Im}}$$ $$\newcommand{\Argument}{\mathrm{Arg}}$$ $$\newcommand{\norm}[1]{\| #1 \|}$$ $$\newcommand{\inner}[2]{\langle #1, #2 \rangle}$$ $$\newcommand{\Span}{\mathrm{span}}$$ $$\newcommand{\id}{\mathrm{id}}$$ $$\newcommand{\Span}{\mathrm{span}}$$ $$\newcommand{\kernel}{\mathrm{null}\,}$$ $$\newcommand{\range}{\mathrm{range}\,}$$ $$\newcommand{\RealPart}{\mathrm{Re}}$$ $$\newcommand{\ImaginaryPart}{\mathrm{Im}}$$ $$\newcommand{\Argument}{\mathrm{Arg}}$$ $$\newcommand{\norm}[1]{\| #1 \|}$$ $$\newcommand{\inner}[2]{\langle #1, #2 \rangle}$$ $$\newcommand{\Span}{\mathrm{span}}$$
In the meantime, here are are some helpful resources to get you started on APA formatting and citation, all courtesy of the Purdue OWL(Online Writing Lab), a great resource that you should check out and use extensively if you are not already doing so! | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.20093737542629242, "perplexity": 307.502258825087}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-21/segments/1652662606992.69/warc/CC-MAIN-20220526131456-20220526161456-00448.warc.gz"} |
https://www.cut-the-knot.org/Probability/TwoVarsityDivisions.shtml | # Two Varsity Divisions
### Solution 1
Twenty teams may be split into two divisions of $10$ teams each in $\displaystyle \frac{1}{2}{20\choose 10}$ ways. Two teams removed, $18$ to be split between the two divisions. For the first question, we need $9$ teams to complete the division with one of the strongest teams (the other division will be filled automatically.) Thus the probability in Question 1 is
$\displaystyle P=\frac{\displaystyle {18\choose 9}}{\displaystyle \frac{1}{2}{20\choose 10}}=\frac{10}{19}.$
For the second question, we need $8$ teams to complete the division of the two strongest teams. Thus the probability in Question 2 is
$\displaystyle P=\frac{\displaystyle {18\choose 8}}{\displaystyle \frac{1}{2}{20\choose 10}}=\frac{9}{19}.$
### Solution 2
Denote, for convenience, the two strongest teams $A$ and $B.$ When $A$ is chosen into one of the divisions, there are $19$ slots that $B$ can fit in. For the first question, $10$ of these slots are in the "other" division, giving the probability as $\displaystyle \frac{10}{19}.$
For the second question, there are $9$ slots in the same division as $A,$ making the probability of $B$ falling there equal to $\displaystyle \frac{9}{19}.$
Naturally, if $A$ and $B$ are not in the same division, then they are in different ones, so that $\displaystyle \frac{10}{19}+\frac{9}{19}=1.$
### Acknowledgment
That's a modification of a problem from A. M. Yaglom, I. M. Yaglom, Challenging Mathematical Problems with Elementary Solutions, Vol I, Dover, 1987. But I have only a Russian edition. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8721330761909485, "perplexity": 425.08116124940045}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-39/segments/1537267158001.44/warc/CC-MAIN-20180922005340-20180922025740-00403.warc.gz"} |
https://reaktoro.org/api/structReaktoro_1_1EquilibriumOptions.html | Reaktoro v2.1.1 A unified framework for modeling chemically reactive systems
EquilibriumOptions Struct Reference
The options for the equilibrium calculations. More...
#include <EquilibriumOptions.hpp>
## Public Attributes
Optima::Options optima
The options for the optimisation solver.
double epsilon = 1e-16
The default lower bound for the amounts of the species.
double logarithm_barrier_factor = 1.0
The value multiplied by epsilon to compute the logarithm barrier penalty parameter $$\tau$$.
bool warmstart = true
The flag indicating if warm-start strategy should be used when possible. More...
bool use_ideal_activity_models = false
The flag indicating if ideal activity models should be used in the calculations.
GibbsHessian hessian = GibbsHessian::PartiallyExact
The calculation mode of the Hessian of the Gibbs energy function.
## Detailed Description
The options for the equilibrium calculations.
## ◆ warmstart
bool warmstart = true
The flag indicating if warm-start strategy should be used when possible.
Setting this flag to true will cause equilibrium calculations to use the correct chemical state as an initial guess to the equilibrium calculation. If the current chemical state is detected to be uninitialized (e.g., all species with zero molar amounts), then cold-start is inevitably used. In this case, a first estimate of a initial guess will be done using a simplex algorithm, which in most cases generates a chemical state that works well as initial guess for all equilibrium algorithms.
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http://math.stackexchange.com/questions/272470/counting-pairs-n-n1-where-n-and-n1-are-both-quadratic-residues-etc | # Counting pairs $(n,n+1)$ where $n$ and $n+1$ are both quadratic residues, etc.?
This is an interesting problem I read that has me stumped.
Let $(RR)$ denote the number of pairs $(n,n+1)$ in the set $\{1,2,\dots,p-1\}$ such that $n$ and $n+1$ are both residues modulo $p$. Let $(NR)$ denote the pairs where $n$ is a nonresidue, and $n+1$ is a residue modulo $p$. Do the same for $(NN)$ and $(RN)$.
The question is, what are $(RR)+(RN),(NR)+(NN),(RR)+(NR),(RN)+(NN)$?
I know that if $g$ is a primitive root, then the residues are the even powers of $g$, and the nonresidues are the odd powers of $g$. So the pairs in $(RR)$ have form $(g^{2k},g^{2j})$, and I would like to count the pairs that can be expressed as $n=g^{2k},n+1=g^{2j}$. This implies $g^{2j}-g^{2k}=1=g^{p-1}$. I could set up similar equations for the other three types of pairs, but I don't see any thing nice to grab onto and work with. Maybe computing $(RR)+(RN)$ is easier than computing $(RR)$ and $(RN)$ separately for some reason?
How could one approach computing these? Thank you.
Source: Ireland/Rosen #5.29
-
Hint: can you spot some mutually exclusive combinations which might combine neatly ... – Mark Bennet Jan 7 '13 at 23:22
Let $p$ be odd. We look at $(RR)+(RN)$. This is almost the number of QR. The only way a QR can fail to be followed by a QR or an NR is if the QR is at $p-1$. This is the case iff $p\equiv 1\pmod{4}$.
So when $p\equiv 1\pmod{4}$, we have $(RR)+(RN)=\frac{p-1}{2}-1$. When $p\equiv -1\pmod{4}$, we have $(RR)+(RN)=\frac{p-1}{2}$. I have not done the other questions. They look much the same. For the last two we have to travel backwards, and note that $1$ is always a QR.
-
Thanks again, I'll try my best to work out the rest. – Noomi Holloway Jan 8 '13 at 8:00
To compute separately see Apostol Chapter 9 Ex 5, p201.
With $\alpha$,$\beta$ being $\pm1$ let $N(\alpha,\beta)$ denote the number of integers $x$ among $1,2,\dots,p-2$ such that $(x|p)=\alpha$ and $(x+1|p)=\beta$ where $p$ is an odd prime. So $N(1,-1)=(RN)$ above. Then
$4N(\alpha,\beta)=\displaystyle\sum_{x=1}^{p-2}(1+\alpha(x|p))(1+\beta(x+1|p))$
since $1+\alpha(x|p)=2$ if $(x|p)=\alpha$; and is $0$ otherwsie. Similarily for $\beta$ so that $(1+\alpha(x|p))(1+\beta(x+1|p))=4$ if $(x|p)=\alpha$ and $(x+1|p)=\beta$; and is $0$ otherwise.
Then expanding the sum we get
$4N(\alpha,\beta)=p-2-\beta-\alpha\beta-\alpha(-1|p)$
using
$\displaystyle\sum_{x=1}^{p-2}(x|p)=-(-1|p)$; $\displaystyle\sum_{x=1}^{p-2}(x+1|p)=-1$ and $\displaystyle\sum_{x=1}^{p-2}(x(x+1)|p)=-1$.
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https://www.physicsforums.com/threads/clarification-about-vectors.910677/ | Tags:
1. Apr 8, 2017
### donaldparida
Background: I have just started studying vector algebra. I studied that physical quantities like velocity, force, momentum, etc. are vectors (My book addresses them as polar vectors/true vectors) and physical quantities like quantities like angular velocity, torque, angular momentum are also vectors (My book addresses them as axial vectors/pseudovectors).
My question/problem: I really do not understand why axial vectors do not have a "curved direction" like clockwise or anticlockwise. For example, torque has a direction which is perpendicular to the force vector and the position vector which i find completely meaningless. Why does it not have a direction like clockwise or anticlockwise (I believe that they are valid directions). I found out on browsing the Internet that this is because they are cross products of two vectors and the cross product of two vectors is a vector whose direction is perpendicular to the plane containing the vectors which are being cross multiplied.
2. Apr 8, 2017
### A.T.
In 3D there is no unique clockwise direction. And it depends on the perspective whether a rotation is CW or CCW. The current convention is the simplest way to encode all the needed information in 3D.
3. Apr 8, 2017
### donaldparida
@A.T. Can you please elaborate on "The current convention is the simplest way to encode all the needed information in 3D.".
4. Apr 8, 2017
### PeroK
If you have motion in 2D, then angular momentum can be represented by a "signed scalar". Positive for clockwise and negative for anticlockwise. But if you have motion in 3D, then you must accept the full vector nature of angular momentum.
Mathematically, the vector (cross) product of two vectors in the x-y plane is a vector in the z-direction. That's why you can shortcut the vector notation and just have use a signed scalar (where the z-direction is implied).
5. Apr 8, 2017
### A.T.
Can you propose a simpler way to encode all information about 3D rotation?
6. Apr 9, 2017
### donaldparida
@A.T. , Ok. Now i got it. Let me write what i have understood (Thanks for reading).
In 3 dimensions, the rotation of an object is possible about any of the infinite number of axes of rotation (There can be infinite number of axes of rotation in 3 dimensions) and for each axis, there is a corresponding clockwise and anticlockwise sense of rotation. Thus in 3 dimensions, to describe the rotational motion of an object and the direction of vectors related to it, it is necessary to specify both the orientation of the axis of rotation as well as the sense of rotation for that particular axis . That is why the direction of an axial vector or pseudovector is perpendicular to the plane containing the two vectors of which it is the cross product and this direction is the same as the orientation of the axis of rotation. In addition, the sense of rotation of the object about an axis can either be clockwise or anticlockwise which is indicated by - and + signs respectively before the magnitude of the axial vector. The orientation of the axis of rotation thus tells us about the direction of the axial vectors in consideration and for that specific orientation of the axis of rotation or direction of the axial vector, the sense of rotation is indicated by - and + signs depending upon whether it is clockwise or anticlockwise respectively. Right?
One more question, Since axial vectors are cross products and cross products are 3 dimensional in nature, how would the direction of them be specified in 2 dimensions or is there no need of specifying the direction since they is only one axis (or point?) of rotation in 2 dimensions or do they not exist in 2 dimensions but only 3 dimensions?
Last edited: Apr 9, 2017
7. Apr 9, 2017
### vanhees71
That's correct.
Another way to state the direction of rotation in connection with axial vectors is the "right-hand rule": point with the thumb of your right hand in direction of the vector, then the fingers give the orientation of the rotation. The most simple quantity to visualize should be angular velocity.
8. Apr 9, 2017
### donaldparida
@vanhees71 , @PeroK and @A.T. , I have a doubt. In 3 dimensions, the direction of axial vectors (which are cross products of two vectors) is determined by applying the right hand rule and this direction automatically encodes the sense of rotation along with orientation of the axis of rotation. Then isn't it unnecessary to point out vectors which are related to clockwise and anticlockwise sense of rotation by using - and + signs respectively?
Last edited: Apr 9, 2017
9. Apr 9, 2017
### vanhees71
The right-hand rule tells you the direction of rotation. That's it. In 3D there's no $\pm$. In 2D one defines that rotating counter-clockwise is by a positive angle.
10. Apr 9, 2017
### A.T.
As already explained, the clockwise concept is not useful in 3D. When you look at a clock from from the back, the pointers of go anticlockwise.
For every axis there are two possible axial vector directions, corresponding to the two possible rotation directions around that axis.
11. Apr 10, 2017
### vanhees71
Yes, and this ambiguity is removed by defining the orientation by the right-hand rule, nicely depicted in your figure.
12. Apr 10, 2017
### donaldparida
Thanks to all! Just for the sake of satisfaction let me write what i have learnt. Please let me know whether i am absolutely correct or not.
Rotation of an object about a fixed point refers to its motion about the point in such a way that the distance of each of the particles comprising it from that point remains constant. This point is known as the **point of rotation or the central point**. A perpendicular passing through the point of rotation is known as the **axis of rotation**. Each point on the axis of rotation remains stationary.
Axial vectors/pseudovectors are cross products of two vectors.
To describe the rotational motion of an object and the direction of vectors related to it (axial vectors) we have to specify the orientation of the axis of rotation along with sense of rotation since there exist infinitely many axes of rotation in 3 dimensions. In 2 dimensions, however, there exists only one axis of rotation, which is oriented along the Z-axis, i.e., it is perpendicular to the X-Y plane.
Therefore in 2 dimensions, the orientation of the axis of rotation is always the same and is implicitly implied. To specify the sense of rotation we add a - sign or a + sign to denote clockwise and anticlockwise sense of rotation respectively.
In 3 dimensions, the rotation of an object is possible about any of the infinite
number of axes of rotation and for each axis, there is a corresponding clockwise and anticlockwise sense of rotation. Thus in 3 dimensions, to describe the rotational motion of an object and the direction of vectors related to it, it is necessary to specify both the orientation of the axis of rotation as well as the sense of rotation for that particular axis. The best way to do this is to use the Right Hand Rule according to which, if the two vectors of which the axial vector is a cross product are placed tail to tail and the right hand is placed along the direction of the first vector and the fingers are curled in the sense in which the first vector should be rotated in order to reach the second vector through the smaller angle, then the direction in which the extended thumb points is the direction of the axial vector. This direction encodes the sense of rotation along with the orientation of the axis (which is perpendicular to the plane containing the two vectors which are being cross-multiplied).
Thus - and + signs are not required in 3 dimensions since the sense of rotation is encoded in the direction of axial vectors along with the orientation of the axis.
13. Apr 10, 2017
### A.T.
Again, the concepts clockwise and anticlockwise do not make much sense here. For any 3D axis there a two possible rotation directions, period.
14. Apr 10, 2017
### vanhees71
...and usually one chooses the orientation according to the right-hand rule.
15. Apr 10, 2017
### zwierz
16. Apr 10, 2017
### PeroK
You need only specify the axis of rotation. If, say, the axis of rotation is the z-axis and the rotation is $\theta$ that means $\theta$ "anticlockwise" about the z-axis. More precisely, the axis of rotation is specified by the positive z-axis - or by unit vector $(0, 0, 1)$.
For a "clockwise" rotation about the z-axis, the axis of rotation is the negative z-axis: the unit vector $(0, 0, -1)$. Or, this is equivalent to a rotation of $-\theta$ about the positive z-axis.
In either case, the rotation is entirely specified by the vector $(0, 0, \theta)$, where $\theta$ can be positive or negative, or simply in the range $0 \le \theta < 2\pi$.
In this way, the "orientation" of the axis of rotation is encapsulated simply by the vector describing the rotation.
The way I remember rotations is that if you look down the axis (i.e. with the axis pointing at you), then a positive rotation is anti-clockwise.
The other thing I remember is that $\vec{i} \times \vec{j} = \vec{k}$. Everything to do with cross products follows from that. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.779390275478363, "perplexity": 299.1129818097611}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257646602.39/warc/CC-MAIN-20180319062143-20180319082143-00154.warc.gz"} |
http://thiagomarzagao.com/teaching/cheaters_hall/ | # cheaters_hall
Here I’ll put the names of the students I catch cheating (plagiarizing, etc), so they are publicly shamed. So far this hall hasn’t been inaugurated (let’s hope that doesn’t change!). | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9370975494384766, "perplexity": 7245.847839894366}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-26/segments/1529267859904.56/warc/CC-MAIN-20180617232711-20180618012711-00229.warc.gz"} |
https://socratic.org/questions/form-the-quaderatic-equation-whose-roots-alpha-and-beta-satisfy-relation-alpha-b | Algebra
Topics
# Form the quadratic equation whose roots alpha and beta satisfy the relations alpha beta=768 and alpha^2+beta^2=1600?
Jan 6, 2018
${x}^{2} - 56 x + 768 = 0$
#### Explanation:
if $\alpha \text{ and } \beta$ are the roots of a quadratic eqn , the eqn can be written as
${x}^{2} - \left(\alpha + \beta\right) x + \alpha \beta = 0$
we are given
$\textcolor{red}{\alpha \beta = 768}$
$\textcolor{b l u e}{{\alpha}^{2} + {\beta}^{2} = 1600}$
now
${\left(\alpha + \beta\right)}^{2} = \textcolor{b l u e}{{\alpha}^{2} + {\beta}^{2}} + \textcolor{red}{2 \alpha \beta}$
so ${\left(\alpha + \beta\right)}^{2} = \textcolor{b l u e}{1600} + 2 \times \textcolor{red}{768} = 3136$
$\therefore \alpha + \beta = \sqrt{3136} = 56$
${x}^{2} - 56 x + 768 = 0$ | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 9, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.98577481508255, "perplexity": 1996.7315106093508}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-45/segments/1603107900200.97/warc/CC-MAIN-20201028162226-20201028192226-00516.warc.gz"} |
https://www.physicsforums.com/threads/nodal-analysis.781322/ | # Nodal Analysis
1. Nov 11, 2014
### _N3WTON_
1. The problem statement, all variables and given/known data
Answer the following questions about the given circuit. These questions will walk you through the steps of the analysis process we call nodal analysis, which is applicable to all electric circuits.
2.1 (3 pts) A quick Fermi-type problem before we start. Use Ohm’s Law to approximate the value of the currents
2.2 (6 pts) Apply KCL at the labeled nodes: Using the currents as defined, write KCL at the labeled nodes. Do not change the direction of any currents from what I have shown! What is the voltage at the right hand end of resistor R3? (Remember that Node 0 serves as the voltage reference or 0V.) How many KCL equations do you have?
2.3 (6 pts) Make the dictionary: Using Ohm's Law, write expressions for all six defined currents.
2.4 (3 pts) Substitute the Ohm's Law expressions for the currents into the equations established in 2.4.
2.5 (6 pts) Write the matrix equation corresponding to the equations you determined in 2.6.
2.6 (3 pts) Use MATLAB or your calculator to solve the matrix equation for the node voltages.
2.7 (3 pts) Now that you know the node voltages, solve for all six currents. Are the values of i3and i6y 0? Does this match your preliminary Fermi estimate?
2. Relevant equations
$I = \frac{V}{R}$
$i = vG$
3. The attempt at a solution
I'm not really knowledgeable about circuits (this is just an introductory lesson). However, for the Fermi problem I was thinking that I could assume that the voltage is constant throughout the parallel parts of the circuit (is this a valid assumption). Furthermore, for part 2.2, I was thinking that I would need to write an Ohm's Law expression for each $i_{a}$. Also, I know that $G = \frac{1}{R}$ so I was planning to account for G that way. I hope this is the right way to proceed, I was hoping someone can confirm. Thanks
2. Nov 11, 2014
### _N3WTON_
I don't believe this problem would be too difficult if it was just a regular circuit, but I am confused about how to account for the extended portion.
3. Nov 11, 2014
### _N3WTON_
I have some values for i, I wanted to see if I am on the right track:
$i_{6} = \frac{10-v{3}}{20}$
$i_{4} = \frac{v_{2}-v{3}}{1}$
$i_{1} = \frac{v_{2}-v_{1}}{41.61}$
I got 41.67 by adding R2 and R1.
Last edited: Nov 11, 2014
4. Nov 11, 2014
### ehild
Take care of the magnitude. 20 in the first equation is 20 MΩ and 1 in the second one is 1 mΩ.
R1 and R2 are parallel resistors, their resultant is not 41.67 Ω.
5. Nov 11, 2014
### _N3WTON_
thanks for the response. I recalculated the resultant of R1 and R2 and found it to be approximately 10 ohms. Assuming, my equations for 'i' above are correct I found the following equations for each node. I was hoping you could let me know if I am on the right track:
Node 3: $\frac{10-v_{3}}{20 M \Omega} - \frac{v_{3}-0}{10 \Omega} - \frac{v_{3}-v_{2}}{1 m \Omega} = 0$
Node 2: $\frac{v_{3}-v_{2}}{1 m \Omega} - \frac{v_{2}-0}{10 \Omega} + 1 = 0$
Node 1: $1 - \frac{v_{2}-v_{1}}{10 \Omega} = 0$
Assuming that these equations are correct, my next step would be to formulate a matrix and plug it into MatLab, no?
Last edited: Nov 11, 2014
6. Nov 11, 2014
### _N3WTON_
I'm thinking that maybe my answer is way off track here, I'm going to read up on the subject and see if I can reach a different conclusion
7. Nov 11, 2014
### ehild
Check node 2. I3 flows through 20 MΩ.
8. Nov 12, 2014
### _N3WTON_
ok here are my updated current equations, I was hoping somebody could let me know if I'm on track here:
$i_{6} = \frac{10-v_{3}}{20M \Omega}$
$i_{4} = \frac{v_{2}-v_{3}}{1m \Omega}$
$i_{1} = \frac{v_{1}-v_{2}}{10 \Omega}$
$i_{3} = \frac{v_{2}-0}{20M \Omega}$
$i_{5} = \frac{v_{3}-0}{10 \Omega}$
And for $i_{2}$ I would not need an equation because I calculated the resultant of resistors $R1 \hspace{2 mm} {and} \hspace{2 mm} R2$ right?
$\frac{1}{R} = \frac{1}{R_{1}} + \frac{1}{R_{2}}$.
I will post my updated Node equations momentarily
9. Nov 12, 2014
### _N3WTON_
Here are my node equations:
Node 3: $\frac{10-v_{3}}{20M \Omega} + \frac{v_{2}-v_{3}}{1m \Omega} - \frac{v_{3}-0}{10 \Omega} = 0$
Node 2: $\frac{v_{1}-v_{2}}{10 \Omega} - \frac{v_{2}-v_{3}}{1m \Omega} - \frac{v_{2}-0}{20M \Omega} = 0$
Node 1: $1 - \frac{v_{1}-v_{2}}{10 \Omega} = 0$
Now I can formulate my matrix, no? Also, the problem asks what the voltage would be at the right hand end of R3, it would just be 10V right?
10. Nov 12, 2014
### _N3WTON_
Also, for the above equations I assumed that current going into a node is positive and current leaving a node is negative.
11. Nov 12, 2014
### _N3WTON_
I'm a little confused about setting up this matrix, is there a specific formula I should follow?
12. Nov 12, 2014
### ehild
You know that v1-v2= 10 V from the third equation.
You are left with 2 unknowns, v2 and v3. Do you say that you can not solve a simple two variable system of equations? :D
Collect the terms with v2 and also the terms with v3. You get two equations of form av2+bv3=Q; cv2+dv3=R.
13. Nov 12, 2014
### _N3WTON_
Thanks for the response again, I'm sure I could solve by hand but I was having trouble figuring out how to formulate a matrix to put in matlab...I'll try by hand first and probably that will help...ps I can solve systems of equations with the best of them :D
14. Nov 12, 2014
### _N3WTON_
Also, just to be sure, what I did(ignoring the extended portion of the circuit) is a legal move because I found the resultant resistance, right?
15. Nov 12, 2014
### ehild
I do not understand what you did. Show your calculation and result.
I am not good in Latex.
You have system of linear equation for v1, v2 and v3 in the form
a11 v1 + a22 v2+a13 v3= Q1
a21 v1 +a22 v2 +a33 v3 = Q2
a31 v1 + a32 v2 +a33 v3 = Q3
Arrange the aik-s in matrix form, and the right side as a vector Q. v1, v2, v3 are also components of the vector v.
Then you have a matrix equation A v = Q
16. Nov 12, 2014
### _N3WTON_
Ok, I was confused about how to deal with the extended portion of the circuit, I was told that you could do this:
$\frac{1}{R} = \frac{1}{R_{1}} + \frac{1}{R_{2}}$
I performed that calculation and found that the resultant was 10 ohms, I was also told that after doing this I could ignore the extended portion of the circuit as long as I wrote that $R_{1} = 10 \Omega$. Somehow, this doesn't seem correct to me though, so I am confused about how to account for the extended portion...I feel like $i_{2}$ must impact the circuit somehow or else it would not have been included in the problem..
17. Nov 12, 2014
### _N3WTON_
Basically I am wondering if $i_{2}$ should appear in my node equations for nodes 1 and 2...
18. Nov 12, 2014
### ehild
You can solve for the voltages v1, v2, v3, without including i1 and i2. Determine them from the equation i1= (v2-v1)/16.67 and i2=(v2-v1)/25.
Or you can write the equations without simplifying, then include both i1 and i2 in the equation for node 1. 1=(v2-v1)/25 + (v2-v1)/16.67.
So you either include both i1 and i2 or only their sum, which is 1 A.
19. Nov 12, 2014
### _N3WTON_
ok, so then my above equation was correct, thanks for the help!
Draft saved Draft deleted
Similar Discussions: Nodal Analysis | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7711005210876465, "perplexity": 832.4348138793775}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-34/segments/1502886106865.74/warc/CC-MAIN-20170820170023-20170820190023-00185.warc.gz"} |
https://www.freqtrade.io/en/2020.12/advanced-hyperopt/ | This page explains some advanced Hyperopt topics that may require higher coding skills and Python knowledge than creation of an ordinal hyperoptimization class.
## Derived hyperopt classes¶
Custom hyperop classes can be derived in the same way it can be done for strategies.
Applying to hyperoptimization, as an example, you may override how dimensions are defined in your optimization hyperspace:
class MyAwesomeHyperOpt(IHyperOpt):
...
# Uses default stoploss dimension
class MyAwesomeHyperOpt2(MyAwesomeHyperOpt):
@staticmethod
def stoploss_space() -> List[Dimension]:
# Override boundaries for stoploss
return [
Real(-0.33, -0.01, name='stoploss'),
]
and then quickly switch between hyperopt classes, running optimization process with hyperopt class you need in each particular case:
$freqtrade hyperopt --hyperopt MyAwesomeHyperOpt --hyperopt-loss SharpeHyperOptLossDaily --strategy MyAwesomeStrategy ... or$ freqtrade hyperopt --hyperopt MyAwesomeHyperOpt2 --hyperopt-loss SharpeHyperOptLossDaily --strategy MyAwesomeStrategy ...
## Creating and using a custom loss function¶
To use a custom loss function class, make sure that the function hyperopt_loss_function is defined in your custom hyperopt loss class. For the sample below, you then need to add the command line parameter --hyperopt-loss SuperDuperHyperOptLoss to your hyperopt call so this function is being used.
A sample of this can be found below, which is identical to the Default Hyperopt loss implementation. A full sample can be found in userdata/hyperopts.
from freqtrade.optimize.hyperopt import IHyperOptLoss
EXPECTED_MAX_PROFIT = 3.0
class SuperDuperHyperOptLoss(IHyperOptLoss):
"""
Defines the default loss function for hyperopt
"""
@staticmethod
min_date: datetime, max_date: datetime,
*args, **kwargs) -> float:
"""
Objective function, returns smaller number for better results
This is the legacy algorithm (used until now in freqtrade).
Weights are distributed as follows:
* 1.0 to total profit, compared to the expected value (EXPECTED_MAX_PROFIT) defined above
"""
total_profit = results['profit_percent'].sum()
profit_loss = max(0, 1 - total_profit / EXPECTED_MAX_PROFIT)
result = trade_loss + profit_loss + duration_loss
return result
Currently, the arguments are:
• results: DataFrame containing the result
The following columns are available in results (corresponds to the output-file of backtesting when used with --export trades):
pair, profit_percent, profit_abs, open_date, open_rate, open_fee, close_date, close_rate, close_fee, amount, trade_duration, open_at_end, sell_reason
• trade_count: Amount of trades (identical to len(results))
• min_date: Start date of the hyperopting TimeFrame
• min_date: End date of the hyperopting TimeFrame
This function needs to return a floating point number (float). Smaller numbers will be interpreted as better results. The parameters and balancing for this is up to you.
Note
This function is called once per iteration - so please make sure to have this as optimized as possible to not slow hyperopt down unnecessarily.
Note
Please keep the arguments *args and **kwargs in the interface to allow us to extend this interface later. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2859911322593689, "perplexity": 9760.210003504946}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296945242.64/warc/CC-MAIN-20230324020038-20230324050038-00031.warc.gz"} |
https://infoscience.epfl.ch/record/183643 | Infoscience
Journal article
# Two-phase heat transfer and high-speed visualization of refrigerant flows in 100 × 100 μm2 silicon multi-microchannels
Two-phase flow boiling of R245fa, R236fa, and R1234ze(E) in 100 × 100 μm2 parallel microchannels for cooling of future 3D-ICs has been investigated. Significant flow instabilities, back flow, and non-uniform flow distribution among the channels were observed in the micro-evaporator without any inlet restrictions (micro-orifices). Therefore, to prevent such problems, rectangular restrictions were placed at the inlet of each channel and the two-phase flow flashed by the micro-orifices was identified as the most optimal operating condition. In the present study, a novel in-situ pixel-by-pixel technique was developed to calibrate the raw infra-red images, thus converting them into two-dimensional temperature fields of 10’000 pixels over the test section surface operating at 60 Hz. Tests showed that the base heat flux of 48.6 W cm−2 could be dissipated whilst keeping the micro-evaporator’s temperature below 85 °C. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8952569365501404, "perplexity": 4238.492439837108}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-30/segments/1500549423723.8/warc/CC-MAIN-20170721062230-20170721082230-00450.warc.gz"} |
http://www.science.gov/topicpages/a/absorption+optical+depth.html | #### Sample records for absorption optical depth
1. Studying Velocity Turbulence from Doppler-broadened Absorption Lines: Statistics of Optical Depth Fluctuations
SciTech Connect
Lazarian, A.; Pogosyan, D.
2008-10-10
We continue our work on developing techniques for studying turbulence with spectroscopic data. We show that Doppler-broadened absorption spectral lines, in particular, saturated absorption lines, can be used within the framework of the previously introduced technique termed the velocity coordinate spectrum (VCS). The VCS relates the statistics of fluctuations along the velocity coordinate to the statistics of turbulence; thus, it does not require spatial coverage by sampling directions in the plane of the sky. We consider lines with different degree of absorption and show that for lines of optical depth less than one, our earlier treatment of the VCS developed for spectral emission lines is applicable, if the optical depth is used instead of intensity. This amounts to correlating the logarithms of absorbed intensities. For larger optical depths and saturated absorption lines, we show that only wings of the line are available for the analysis. In terms of the VCS formalism, this results in introducing an additional window, whose size decreases with the increase of the optical depth. As a result, strongly saturated absorption lines only carry the information about the small-scale turbulence. Nevertheless, the contrast of the fluctuations corresponding to the small-scale turbulence increases with the increase of the optical depth, which provides advantages for studying turbulence by combining lines with different optical depths. By combining different absorption lines one can develop a tomography of the turbulence in the interstellar gas in all its complexity.
2. Optical absorption depth profiling of photodegraded poly(vinylchloride) (PVC) films by quantitative photothermal deflection technique
Fu, S.-W.; Power, J. F.; Nepotchatykh, O. V.
2000-05-01
An improved photothermal beam deflection technique is applied for optical absorption depth profiling of UV photodegraded PVC films, for nondestructive evaluation of their decomposition mechanism. A new model-based on diffraction theory is used to describe the photothermal response (with bicell recording), induced by impulse irradiation of a depth dependent array of thin planar optical absorbers approximating the sample's depth profile. Improved techniques of alignment, sample preparation and quantitative deconvolution of the bicell impulse response have increased the signal repeatability and reduced the principal bias errors affecting this ill posed problem. By this technique and a stable solution of the inverse problem, the absorption coefficient depth profile is accurately reconstructed in PVC films. Experimental depth profiles were confirmed against destructive techniques run on identical samples of the degraded material. An excellent agreement was found between depth profiles recovered using the mirage effect and these reference methods. Observed absorption profiles were fully consistent with known patterns of depth dependent PVC degradation under nitrogen and oxygen atmospheres.
3. Total ozone and aerosol optical depths inferred from radiometric measurements in the Chappuis absorption band
SciTech Connect
Flittner, D.E.; Herman, B.M.; Thome, K.J.; Simpson, J.M.; Reagan, J.A. )
1993-04-15
A second-derivative smoothing technique, commonly used in inversion work, is applied to the problem of inferring total columnar ozone amounts and aerosol optical depths. The application is unique in that the unknowns (i.e., total columnar ozone and aerosol optical depth) may be solved for directly without employing standard inversion methods. It is shown, however, that by employing inversion constraints, better solutions are normally obtained. The current method requires radiometric measurements of total optical depth through the Chappuis ozone band. It assumes no a priori shape for the aerosol optical depth versus wavelength profile and makes no assumptions about the ozone amount. Thus, the method is quite versatile and able to deal with varying total ozone and various aerosol size distributions. The technique is applied first in simulation, then to 119 days of measurements taken in Tucson, Arizona, that are compared to TOMS values for the same dates. The technique is also applied to two measurements taken at Mauna Loa, Hawaii, for which Dobson ozone values are available in addition to the TOMS values, and the results agree to within 15%. It is also shown through simulations that additional information can be obtained from measurements outside the Chappuis band. This approach reduces the bias and spread of the estimates total ozone and is unique in that it uses measurements from both the Chappuis and Huggins absorption bands. 12 refs., 6 figs., 2 tabs.
4. The long-term global record on Aerosol Absorption Optical Depth from TOMS and OMI observations
Torres, O.; Bhartia, P.; Ahn, C.; Veefkind, P.
2006-12-01
Carbonaceous aerosols from biomass burning and boreal forest fires, and desert dust lofted by the winds from the world major arid and semi-arid areas are among the most long-lived aerosol types in the Earth's atmosphere, since they often reach the free troposphere and are sometimes transported thousands of kilometers from their original sources. A lot has been learned about the global distribution of aerosol sources, and the transport patterns of these aerosol types since the development of the near-UV methods of aerosol detection and characterization using data from the TOMS series of instruments. Because both smoke and desert dust aerosols absorb UV-radiation, the TOMS aerosol sensing technique is specially suited for tracking these aerosol types over variety of surfaces including clouds and snow. TOMS aerosol observations, for instance, have been fundamental in discovering that carbonaceous aerosols associated with wild fires at mid and high latitudes often reach the lower stratosphere, and travel as far as the remote polar regions. We have recently completed the development of an improved algorithm to derive quantitative information about aerosol absorption optical depth using near-UV data. We will discuss the multi- decadal global record on aerosol absorption optical depth produced using TOMS and OMI sensors, and review the multiple contributions of the TOMS-OMI record to the current understanding of the factors that govern the observed temporal and spatial distribution of smoke and desert dust aerosols.
5. Case study of absorption aerosol optical depth closure of black carbon over the East China Sea
Koike, M.; Moteki, N.; Khatri, P.; Takamura, T.; Takegawa, N.; Kondo, Y.; Hashioka, H.; Matsui, H.; Shimizu, A.; Sugimoto, N.
2014-01-01
6. Using the OMI aerosol index and absorption aerosol optical depth to evaluate the NASA MERRA Aerosol Reanalysis
Buchard, V.; da Silva, A. M.; Colarco, P. R.; Darmenov, A.; Randles, C. A.; Govindaraju, R.; Torres, O.; Campbell, J.; Spurr, R.
2015-05-01
A radiative transfer interface has been developed to simulate the UV aerosol index (AI) from the NASA Goddard Earth Observing System version 5 (GEOS-5) aerosol assimilated fields. The purpose of this work is to use the AI and aerosol absorption optical depth (AAOD) derived from the Ozone Monitoring Instrument (OMI) measurements as independent validation for the Modern Era Retrospective analysis for Research and Applications Aerosol Reanalysis (MERRAero). MERRAero is based on a version of the GEOS-5 model that is radiatively coupled to the Goddard Chemistry, Aerosol, Radiation, and Transport (GOCART) aerosol module and includes assimilation of aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Since AI is dependent on aerosol concentration, optical properties and altitude of the aerosol layer, we make use of complementary observations to fully diagnose the model, including AOD from the Multi-angle Imaging SpectroRadiometer (MISR), aerosol retrievals from the AErosol RObotic NETwork (AERONET) and attenuated backscatter coefficients from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission to ascertain potential misplacement of plume height by the model. By sampling dust, biomass burning and pollution events in 2007 we have compared model-produced AI and AAOD with the corresponding OMI products, identifying regions where the model representation of absorbing aerosols was deficient. As a result of this study over the Saharan dust region, we have obtained a new set of dust aerosol optical properties that retains consistency with the MODIS AOD data that were assimilated, while resulting in better agreement with aerosol absorption measurements from OMI. The analysis conducted over the southern African and South American biomass burning regions indicates that revising the spectrally dependent aerosol absorption properties in the near-UV region improves the modeled-observed AI comparisons
7. Using the OMI Aerosol Index and Absorption Aerosol Optical Depth to Evaluate the NASA MERRA Aerosol Reanalysis.
Buchard, V.; da Silva, A. M., Jr.; Colarco, P. R.; Darmenov, A.; Govindaraju, R.
2014-12-01
A radiative transfer interface has been developed to simulate the UV Aerosol Index (AI) from the NASA Goddard Earth Observing System version 5 (GEOS-5) aerosol assimilated fields. The purpose of this work is to use the AI derived from the Ozone Monitoring Instrument (OMI) measurements as independent validation for the Modern Era Retrospective analysis for Research and Applications Aerosol Reanalysis (MERRAero). In this presentation we show comparisons of model produced AI with the corresponding OMI measurements during several months of 2007 characterized by a good sampling of dust and biomass burning events. In parallel, model produced Absorption Aerosol Optical Depth (AAOD) were compared to OMI AAOD for the same period, identifying regions where the model representation of absorbing aerosols were deficient. Since AI is dependent on aerosol concentration, optical properties and altitude of the aerosol layer, we make use of complementary observations to fully diagnose the model, including AOD from the Multi-angle Imaging SpectroRadiometer (MISR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors, aerosol retrievals from the Aerosol Robotic Network (AERONET) and attenuated backscatter coefficients from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission to ascertain misplacement of plume height by the model.
8. Simulations of the Aerosol Index and the Absorption Aerosol Optical Depth and Comparisons with OMI Retrievals During ARCTAS-2008 Campaign
NASA Technical Reports Server (NTRS)
2010-01-01
We have computed the Aerosol Index (AI) at 354 nm, useful for observing the presence of absorbing aerosols in the atmosphere, from aerosol simulations conducted with the Goddard Chemistry, Aerosol, Radiation, and Transport (GOCART) module running online the GEOS-5 Atmospheric GCM. The model simulates five aerosol types: dust, sea salt, black carbon, organic carbon and sulfate aerosol and can be run in replay or data assimilation modes. In the assimilation mode, information's provided by the space-based MODIS and MISR sensors constrains the model aerosol state. Aerosol optical properties are then derived from the simulated mass concentration and the Al is determined at the OMI footprint using the radiative transfer code VLIDORT. In parallel, model derived Absorption Aerosol Optical Depth (AAOD) is compared with OMI retrievals. We have focused our study during ARCTAS (June - July 2008), a period with a good sampling of dust and biomass burning events. Our ultimate goal is to use OMI measurements as independent validation for our MODIS/MISR assimilation. Towards this goal we document the limitation of OMI aerosol absorption measurements on a global scale, in particular sensitivity to aerosol vertical profile and cloud contamination effects, deriving the appropriate averaging kernels. More specifically, model simulated (full) column integrated AAOD is compared with model derived Al, this way identifying those regions and conditions under which OMI cannot detect absorbing aerosols. Making use of ATrain cloud measurements from MODIS, C1oudSat and CALIPSO we also investigate the global impact on clouds on OMI derived Al, and the extent to which GEOS-5 clouds can offer a first order representation of these effects.
9. The Global Ozone and Aerosol Profiles and Aerosol Hygroscopic Effect and Absorption Optical Depth (GOA2HEAD) Network Initiative
Gao, R. S.; Elkins, J. W.; Frost, G. J.; McComiskey, A. C.; Murphy, D. M.; Ogren, J. A.; Petropavlovskikh, I. V.; Rosenlof, K. H.
2014-12-01
Inverse modeling using measurements of ozone (O3) and aerosol is a powerful tool for deriving pollutant emissions. Because they have relatively long lifetimes, O3 and aerosol are transported over large distances. Frequent and globally spaced vertical profiles rather than ground-based measurements alone are therefore highly desired. Three requirements necessary for a successful global monitoring program are: Low equipment cost, low operation cost, and reliable measurements of known uncertainty. Conventional profiling using aircraft provides excellent data, but is cost prohibitive on a large scale. Here we describe a new platform and instruments meeting all three global monitoring requirements. The platform consists of a small balloon and an auto-homing glider. The glider is released from the balloon at about 5 km altitude, returning the light instrument package to the launch location, and allowing for consistent recovery of the payload. Atmospheric profiling can be performed either during ascent or descent (or both) depending on measurement requirements. We will present the specifications for two instrument packages currently under development. The first measures O3, RH, p, T, dry aerosol particle number and size distribution, and aerosol optical depth. The second measures dry aerosol particle number and size distribution, and aerosol absorption coefficient. Other potential instrument packages and the desired spatial/temporal resolution for the GOA2HEAD monitoring initiative will also be discussed.
10. Constraining Black Carbon Aerosol over Asia using OMI Aerosol Absorption Optical Depth and the Adjoint of GEOS-Chem
NASA Technical Reports Server (NTRS)
Zhang, Li; Henze, David K.; Grell, Georg A.; Carmichael. Gregory R.; Bousserez, Nicolas; Zhang, Qiang; Torres, Omar; Ahn, Changwoo; Lu, Zifeng; Cao, Junji; Mao, Yuhao
2015-01-01
Accurate estimates of the emissions and distribution of black carbon (BC) in the region referred to here as Southeastern Asia (70degE-l50degE, 11degS-55degN) are critical to studies of the atmospheric environment and climate change. Analysis of modeled BC concentrations compared to in situ observations indicates levels are underestimated over most of Southeast Asia when using any of four different emission inventories. We thus attempt to reduce uncertainties in BC emissions and improve BC model simulations by developing top-down, spatially resolved, estimates of BC emissions through assimilation of OMI observations of aerosol absorption optical depth (AAOD) with the GEOS-Chem model and its adjoint for April and October of 2006. Overwhelming enhancements, up to 500%, in anthropogenic BC emissions are shown after optimization over broad areas of Southeast Asia in April. In October, the optimization of anthropogenic emissions yields a slight reduction (1-5%) over India and parts of southern China, while emissions increase by 10-50% over eastern China. Observational data from in situ measurements and AERONET observations are used to evaluate the BC inversions and assess the bias between OMI and AERONET AAOD. Low biases in BC concentrations are improved or corrected in most eastern and central sites over China after optimization, while the constrained model still underestimates concentrations in Indian sites in both April and October, possibly as a. consequence of low prior emissions. Model resolution errors may contribute up to a factor of 2.5 to the underestimate of surface BC concentrations over northern India. We also compare the optimized results using different anthropogenic emission inventories and discuss the sensitivity of top-down constraints on anthropogenic emissions with respect to biomass burning emissions. In addition, the impacts of brown carbon, the formulation of the observation operator, and different a priori constraints on the optimization are
11. Optical absorption measurement system
DOEpatents
Draggoo, Vaughn G.; Morton, Richard G.; Sawicki, Richard H.; Bissinger, Horst D.
1989-01-01
The system of the present invention contemplates a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature.
12. Characterization of penetration depth as a function of optical fiber separation at various absorption and scatter coefficients for a noninvasive metabolic sensor
DeMilo, Charles; Brukilacchio, Thomas; Soller, Babs R.; Soyemi, Olusola
2004-06-01
A visible-near IR (500-1,000nm) fiber optic sensor is under development that is intended to non-invasively assess muscle metabolism through the measurement of tissue pH and oxygen partial pressure. These parameters are calculated from the spectra of hemoglobin and myoglobin in muscle. The sensor consists of transmit (illumination) fibers and receive (detection) fibers that are coupled to a spectrometer. Light from the probe must penetrate below the surface of the skin and into a 5-10mm thick layer of muscle. A study was conducted to quantify the relationship between transmit and receive fiber separation and sensor penetration depth below the surface of the skin. A liquid phantom was created to replicate the absorption (μa) and reduced scatter coefficient (μs') profiles typically found in human blood and tissue. The phantom consisted of a solution of Intralipid and India ink in the appropriate concentrations to achieve desired reduced scatter coefficient and absorption profiles. The reduced scatter coefficient of the liquid phantom was achieved to an accuracy of +/-10% compared to previously published data. A fixed illumination fiber and translatable detector fiber were placed in the liquid phantom, and the fiber separation was varied from 3-40mm. Values of μa and μs' varied from 0.03-0.40 cm-1 and 5.0-15.0 cm-1 respectively. Results from the experiment demonstrate a strong correlation between penetration depth and fiber separation. Additionally, it was found that penetration depth was not substantially influenced by absorption and scatter concentration. As signal-to-noise is an important parameter in many non-invasive biomedical applications, the relative signal as a function of fiber separation was determined to follow an exponential relationship.
13. The Relationship between the Optical Depth of the 9.7 μm Silicate Absorption Feature and Infrared Differential Extinction in Dense Clouds
Chiar, J. E.; Ennico, K.; Pendleton, Y. J.; Boogert, A. C. A.; Greene, T.; Knez, C.; Lada, C.; Roellig, T.; Tielens, A. G. G. M.; Werner, M.; Whittet, D. C. B.
2007-09-01
We have examined the relationship between the optical depth of the 9.7 μm silicate absorption feature (τ9.7) and the near-infrared color excess, E(J-Ks), in the Serpens, Taurus, IC 5146, Chameleon I, Barnard 59, and Barnard 68 dense clouds/cores. Our data set, based largely on Spitzer IRS spectra, spans E(J-Ks)=0.3-10 mag (corresponding to visual extinction between about 2 and 60 mag). All lines of sight show the 9.7 μm silicate feature. Unlike in the diffuse ISM where a tight linear correlation between the 9.7 μm silicate feature optical depth and the extinction (AV) is observed, we find that the silicate feature in dense clouds does not show a monotonic increase with extinction. Thus, in dense clouds, τ9.7 is not a good measure of total dust column density. With few exceptions, the measured τ9.7 values fall well below the diffuse ISM correlation line for E(J-Ks)>2 mag (AV>12 mag). Grain growth via coagulation is a likely cause of this effect.
14. Aerosols in GEOS-5: simulations of the UV Aerosol Index and the Aerosol Absorption Optical Depth and comparisons with OMI retrievals.
Buchard-Marchant, Virginie; da Silva, Arlindo; Colarco, Peter; Darmenov, Anton; Govindaraju, Ravi
2013-04-01
GEOS-5 is the latest version of the NASA Global Modeling and Assimilation Office (GMAO) earth system model. GEOS-5 contains components for atmospheric circulation and composition (including data assimilation), ocean circulation and biogeochemistry, and land surface processes. In addition to traditional meteorological parameters, GEOS-5 includes modules representing the atmospheric composition, most notably aerosols and tropospheric/stratospheric chemical constituents, taking explicit account of the impact of these constituents on the radiative processes of the atmosphere. The assimilation of Aerosol Optical Depth (AOD) in GEOS-5 involves very careful cloud screening and homogenization of the observing system by means of a Neural Net scheme that translates MODIS radiances into AERONET calibrated AOD. These measurements are further quality controlled using an adaptive buddy check scheme, and assimilated using the Local Displacement Ensemble (LDE) methodology. For this analysis, GEOS-5 runs at a nominal 50km horizontal resolution with 72 vertical layers (top at ~85km). GEOS-5 is driven by daily biomass burning emissions derived from MODIS fire radiative power retrievals. We present a summary of our efforts to simulate the UV Aerosol Index (AI) at 354 nm from aerosol simulations by performing a radiative transfer calculation. We have compared model produced AI with the corresponding OMI measurements, identifying regions where the model representation of absorbing aerosols were deficient. Separately, model derived Absorption Aerosol Optical Depth (AAOD) is compared with OMI retrievals. Making use of CALIPSO measurements we have also investigated the impact of the altitude of the aerosol layer on OMI derived AI trying to ascertain misplacement of plume height by the model.
15. Aerosol optical depth measuring network - project description
Aaltonen, A.; Koskela, K.; Lihavainen, L.
2003-04-01
The Finnish Meteorological Institute (FMI), in collaboration with Servicio Meteorológico Nacional (SMN), Argentina, is constructing a network for aerosol optical depth (AOD) measurements. Measurements are to be started in the summer 2003 with three sunphotometers, model PFR, Davos. One of them will be sited in Marambio (64°S), Antarctica, and the rest two in the Observatory of Jokioinen (61°N) and Sodankylä GAW station (67°N), Finland. Each instrument consists of a precision filter radiometer and a suntracker. Due to the harsh climate conditions special solutions had to be introduced to keep the instrument warm and free from snow. Aerosol optical depth measured at Pallas-Sodankylä GAW station can be compared with estimated aerosol extinction, which is calculated from ground base aerosol scattering and absorption coefficient measurements.
16. Assimilation of Aerosol Optical Depths
Verver, Gé; Henzing, Bas
Climate predictions are hampered by the large uncertainties involved in the estima- tion of the effects of atmospheric aerosol (IPCC,2001). These uncertainties are caused partly because sources and sinks as well as atmospheric processing of the different types of aerosol are not accurately known. Moreover, the climate impact (especially the indirect effect) of a certain distribution of aerosol is hard to quantify. There have been different approaches to reduce these uncertainties. In recent years intensive ob- servational campaigns such as ACE and INDOEX have been carried out, aiming to in- crease our knowledge of atmospheric processes that determine the fate of atmospheric aerosols and to quantify the radiation effects. With the new satellite instruments such as SCIAMACHY and OMI it will be possible in the near future to derive the ge- ographical distribution of the aerosol optical depths (AOD) and perhaps additional information on the occurrence of different aerosol types. The goal of the ARIA project (started in 2001) is to assimilate global satellite de- rived aerosol optical depth (AOD) in an off-line chemistry/transport model TM3. The TM3 model (Jeuken et al. 2001) describes sources, sinks, transformation and transport processes of different types of aerosol (mineral dust, carbon, sulfate, nitrate) that are relevant to radiative forcing. All meteorological input is provided by ECMWF. The assimilation procedure constrains the aerosol distribution produced by the model on the basis of aerosol optical depths observed by satellite. The product, i.e. an optimal estimation of global aerosol distribution, is then available for the calculation of radia- tive forcing. Error analyses may provide valuable information on deficiencies of the model. In the ARIA project it is tried to extract additional information on the type of aerosol present in the atmosphere by assimilating AOD at multiple wavelengths. First results of the ARIA project will be presented. The values
17. Analyzing Water's Optical Absorption
NASA Technical Reports Server (NTRS)
2002-01-01
A cooperative agreement between World Precision Instruments (WPI), Inc., and Stennis Space Center has led the UltraPath(TM) device, which provides a more efficient method for analyzing the optical absorption of water samples at sea. UltraPath is a unique, high-performance absorbance spectrophotometer with user-selectable light path lengths. It is an ideal tool for any study requiring precise and highly sensitive spectroscopic determination of analytes, either in the laboratory or the field. As a low-cost, rugged, and portable system capable of high- sensitivity measurements in widely divergent waters, UltraPath will help scientists examine the role that coastal ocean environments play in the global carbon cycle. UltraPath(TM) is a trademark of World Precision Instruments, Inc. LWCC(TM) is a trademark of World Precision Instruments, Inc.
18. Optical Absorption in Liquid Semiconductors
Bell, Florian Gene
An infrared absorption cell has been developed which is suitable for high temperature liquids which have absorptions in the range .1-10('3) cm('-1). The cell is constructed by clamping a gasket between two flat optical windows. This unique design allows the use of any optical windows chemically compatible with the liquid. The long -wavelength limit of the measurements is therefore limited only by the choice of the optical windows. The thickness of the cell can easily be set during assembly, and can be varied from 50 (mu)m to .5 cm. Measurements of the optical absorption edge were performed on the liquid alloy Se(,1-x)Tl(,x) for x = 0, .001, .002, .003, .005, .007, and .009, from the melting point up to 475(DEGREES)C. The absorption was found to be exponential in the photon energy over the experimental range from 0.3 eV to 1.2 eV. The absorption increased linearly with concentration according to the empirical relation (alpha)(,T)(h(nu)) = (alpha)(,1) + (alpha)(,2)x, and the absorption (alpha)(,1) was interpreted as the absorption in the absence of T1. (alpha)(,1) also agreed with the measured absorption in 100% Se at corresponding temperatures and energies. The excess absorption defined by (DELTA)(alpha) = (alpha)(,T)(h(nu))-(alpha)(,1) was interpreted as the absorption associated with Tl and was found to be thermally activated with an activation energy E(,t) = 0.5 eV. The exponential edge is explained as absorption on atoms immersed in strong electric fields surrounding ions. The strong fields give rise to an absorption tail similar to the Franz-Keldysh effect. A simple calculation is performed which is based on the Dow-Redfield theory of absorption in an electric field with excitonic effects included. The excess absorption at low photon energies is proportional to the square of the concentration of ions, which are proposed to exist in the liquid according to the relation C(,i) (PROPORTIONAL) x(' 1/2)(.)e('-E)t('/kT), which is the origin of the thermal activation
19. Optical absorption of silicon nanowires
SciTech Connect
Xu, T.; Lambert, Y.; Krzeminski, C.; Grandidier, B.; Stievenard, D.; Leveque, G.; Akjouj, A.; Pennec, Y.; Djafari-Rouhani, B.
2012-08-01
We report on simulations and measurements of the optical absorption of silicon nanowires (NWs) versus their diameter. We first address the simulation of the optical absorption based on two different theoretical methods: the first one, based on the Green function formalism, is useful to calculate the scattering and absorption properties of a single or a finite set of NWs. The second one, based on the finite difference time domain (FDTD) method, is well-adapted to deal with a periodic set of NWs. In both cases, an increase of the onset energy for the absorption is found with increasing diameter. Such effect is experimentally illustrated, when photoconductivity measurements are performed on single tapered Si nanowires connected between a set of several electrodes. An increase of the nanowire diameter reveals a spectral shift of the photocurrent intensity peak towards lower photon energies that allow to tune the absorption onset from the ultraviolet radiations to the visible light spectrum.
20. Hyperspectral Aerosol Optical Depths from TCAP Flights
SciTech Connect
Shinozuka, Yohei; Johnson, Roy R.; Flynn, Connor J.; Russell, P. B.; Schmid, Beat; Redemann, Jens; Dunagan, Stephen; Kluzek, Celine D.; Hubbe, John M.; Segal-Rosenheimer, Michal; Livingston, J. M.; Eck, T.; Wagener, Richard; Gregory, L.; Chand, Duli; Berg, Larry K.; Rogers, Ray; Ferrare, R. A.; Hair, John; Hostetler, Chris A.; Burton, S. P.
2013-11-13
4STAR (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research), the world’s first hyperspectral airborne tracking sunphotometer, acquired aerosol optical depths (AOD) at 1 Hz during all July 2012 flights of the Two Column Aerosol Project (TCAP). Root-mean square differences from AERONET ground-based observations were 0.01 at wavelengths between 500-1020 nm, 0.02 at 380 and 1640 nm and 0.03 at 440 nm in four clear-sky fly-over events, and similar in ground side-by-side comparisons. Changes in the above-aircraft AOD across 3-km-deep spirals were typically consistent with integrals of coincident in situ (on DOE Gulfstream 1 with 4STAR) and lidar (on NASA B200) extinction measurements within 0.01, 0.03, 0.01, 0.02, 0.02, 0.02 at 355, 450, 532, 550, 700, 1064 nm, respectively, despite atmospheric variations and combined measurement uncertainties. Finer vertical differentials of the 4STAR measurements matched the in situ ambient extinction profile within 14% for one homogeneous column. For the AOD observed between 350-1660 nm, excluding strong water vapor and oxygen absorption bands, estimated uncertainties were ~0.01 and dominated by (then) unpredictable throughput changes, up to +/-0.8%, of the fiber optic rotary joint. The favorable intercomparisons herald 4STAR’s spatially-resolved high-frequency hyperspectral products as a reliable tool for climate studies and satellite validation.
1. Vertical Profiles of Light Scattering, Light Absorption, and Single Scattering Albedo during the Dry, Biomass Burning Season in Southern Africa and Comparisons of In Situ and Remote Sensing Measurements of Aerosol Optical Depths
NASA Technical Reports Server (NTRS)
Magi, Brian I.; Hobbs, Peter V.; Schmid, Beat; Redermann, Jens
2003-01-01
Airborne in situ measurements of vertical profiles of aerosol light scattering, light absorption, and single scattering albedo (omega (sub 0)) are presented for a number of locations in southern Africa during the dry, biomass burning season. Features of the profiles include haze layers, clean air slots, and marked decreases in light scattering in passing from the boundary layer into the free troposphere. Frequency distributions of omega (sub 0) reflect the strong influence of smoke from biomass burning. For example, during a period when heavy smoke was advected into the region from the north, the mean value of omega (sub 0) in the boundary layer was 0.81 +/- 0.02 compared to 0.89 +/- 0.03 prior to this intrusion. Comparisons of layer aerosol optical depths derived from the in situ measurements with those measured by a Sun photometer aboard the aircraft show excellent agreement.
2. Optical absorption in trilayer graphene
Li, Xiao; Zhang, Fan; Niu, Qian
2013-03-01
We use a low energy effective model to analyze the optical responses of trilayer graphene samples. We first show that optical absorption of the ABA-stacked trilayer has strong dependence on both the Fermi energy and optical frequency, which is in sharp contrast to that of ABC-stacked trilayer graphene. Secondly, we are able to determine the possible existence of trigonal warping effects in the bandstructure of ABC-stacked trilayer graphene by a divergence in the absorption spectra at around 10 meV. In addition, we can partially distinguish the vairious broken symmetry states driven by electron-electron interactions in ABC-stacked trilayer graphene. In particular, the quantum anomalous Hall (QAH) state is sensitive to the polarization of the incident light, giving a way to detect its possible existence.
3. Electro-optical liquid depth sensor
NASA Technical Reports Server (NTRS)
Heppner, D. B.; Atwood, S. O.
1976-01-01
Transducer utilizes absorptive properties of water to determine variations in depth without disturbing liquid. Instrument is inexpensive, simple, and small and thus can be used in lieu of direct graduated scale readout or capacitive, ultrasonic, resistive or inducive sensors when these are impractical because of complexity or cost.
4. Evaluation of Air Pollution Applications of AERONET and MODIS Aerosol Column Optical Depth by Comparison with In Situ Measurements of Aerosol Light Scattering and Absorption for Reno, NV, USA
Loria Salazar, S.; Arnott, W. P.; Moosmuller, H.; Colucci, D.
2012-12-01
Reno, Nevada, USA is subject to typical urban aerosol, wind-blown dust, and occasional biomass burning smoke from anthropogenic and natural fires. Reno has complex air flow at levels relevant for aerosol transport. At times recirculating mountain and urban flow arrives from the Sierra Nevada, San Francisco, CA and Sacramento, CA. The urban plumes are further modified by biogenic forest emissions and secondary aerosol formation during transport over the Sierra Nevada Mountains to Reno. This complicates the use of MODIS aerosol optical depth (AOD) for air quality measurements in Reno. Our laboratory at the University of Nevada Reno has collocated multispectral photoacoustic instruments and reciprocal nephelometers to measure light absorption and light scattering coefficients as well as an AERONET operated CIMEL CE-318 ground-based sunphotometer. Preliminary measurements from August 2011 indicate substantially larger Cimel AOD than could be accounted for by use of the in situ aerosol extinction measurements combined with mixing height estimate. This poster presents new results comparing AERONET AOD and single scattering albedo and MODIS AOD with in situ measurements for summer and fall 2012, along with extensive back trajectory analysis, to evaluate conditions when satellite measurement may be useful for air pollution applications in Reno.
5. Depth selective acousto-optic flow measurement
PubMed Central
Tsalach, Adi; Schiffer, Zeev; Ratner, Eliahu; Breskin, Ilan; Zeitak, Reuven; Shechter, Revital; Balberg, Michal
2015-01-01
Optical based methods for non-invasive measurement of regional blood flow tend to incorrectly assess cerebral blood flow, due to contribution of extra-cerebral tissues to the obtained signal. We demonstrate that spectral analysis of phase-coded light signals, tagged by specific ultrasound patterns, enables differentiation of flow patterns at different depths. Validation of the model is conducted by Monte Carlo simulation. In-vitro experiments demonstrate good agreement with the simulations' results and provide a solid validation to depth discrimination ability. These results suggest that signal contamination originating from extra-cerebral tissue may be eliminated using spectral analysis of ultrasonically tagged light. PMID:26713201
6. Aerosol Optical Depth Determinations for BOREAS
NASA Technical Reports Server (NTRS)
Wrigley, R. C.; Livingston, J. M.; Russell, P. B.; Guzman, R. P.; Ried, D.; Lobitz, B.; Peterson, David L. (Technical Monitor)
1994-01-01
Automated tracking sun photometers were deployed by NASA/Ames Research Center aboard the NASA C-130 aircraft and at a ground site for all three Intensive Field Campaigns (IFCs) of the Boreal Ecosystem-Atmosphere Study (BOREAS) in central Saskatchewan, Canada during the summer of 1994. The sun photometer data were used to derive aerosol optical depths for the total atmospheric column above each instrument. The airborne tracking sun photometer obtained data in both the southern and northern study areas at the surface prior to takeoff, along low altitude runs near the ground tracking sun photometer, during ascents to 6-8 km msl, along remote sensing flightlines at altitude, during descents to the surface, and at the surface after landing. The ground sun photometer obtained data from the shore of Candle Lake in the southern area for all cloud-free times. During the first IFC in May-June ascents and descents of the airborne tracking sun photometer indicated the aerosol optical depths decreased steadily from the surface to 3.5 kni where they leveled out at approximately 0.05 (at 525 nm), well below levels caused by the eruption of Mt. Pinatubo. On a very clear day, May 31st, surface optical depths measured by either the airborne or ground sun photometers approached those levels (0.06-0.08 at 525 nm), but surface optical depths were often several times higher. On June 4th they increased from 0.12 in the morning to 0.20 in the afternoon with some evidence of brief episodes of pollen bursts. During the second IFC surface aerosol optical depths were variable in the extreme due to smoke from western forest fires. On July 20th the aerosol optical depth at 525 nm decreased from 0.5 in the morning to 0.2 in the afternoon; they decreased still further the next day to 0.05 and remained consistently low throughout the day to provide excellent conditions for several remote sensing missions flown that day. Smoke was heavy for the early morning of July 24th but cleared partially by 10
7. Optical design for large depth of field
Shen, Yang; Wang, Hu; Yue, Pan; Xue, Yaoke; Liu, Jie; Ye, Shuifu
2016-01-01
Optical system with large depth of field and large field of view has been designed. To enforce optical system with focal length of 6 mm to imaging the object with object length of 200mmm-1200mm, accord to the equation of depth of field, in case of the CCD sensor with pixel of 5.5umx 5.5um square area, the entrance pupil diameter to ideal imaging will be 0.423mm. To enlarge the modulation transfer function (MTF) at spatial frequency of 90 lp/mm, the entrance pupil diameter is enlarged to 1mm.After design and optimization, with field of view of 80°, within object length of 200mm - 1200mm, the optical system can imaging well, the modulation transfer function (MTF) at spatial frequency of 90lp/mm is larger than 0.1, the distortion of full field of viewed is less than 3%.The optical system can be widely used in machine vision, surveillance cameras, etc.
8. Modeling optical absorption for thermoreflectance measurements
Yang, Jia; Ziade, Elbara; Schmidt, Aaron J.
2016-03-01
Optical pump-probe techniques based on thermoreflectance, such as time domain thermoreflectance and frequency domain thermoreflectance (FDTR), have been widely used to characterize the thermal conductivity of thin films and the thermal conductance across interfaces. These techniques typically use a transducer layer to absorb the pump light and improve the thermoreflectance signal. The transducer, however, complicates the interpretation of the measured signal because the approximation that all the energy from the pump beam is deposited at the transducer surface is not always accurate. In this paper, we consider the effect of laser absorption in the top layer of a multilayer sample, and derive an analytical solution for the thermoreflectance signal in the diffusion regime based on volumetric heating. We analyze the measurement sensitivity to the pump absorption depth for transducers with different thermal conductivities, and investigate the additional effect of probe laser penetration depth on the measured signal. We validate our model using FDTR measurements on 490 nm thick amorphous silicon films deposited on fused silica and silicon substrates.
9. Diurnal variations in optical depth at Mars
NASA Technical Reports Server (NTRS)
Colburn, D. S.; Pollack, J. B.; Haberle, R. M.
1989-01-01
Viking lander camera images of the Sun were used to compute atmospheric optical depth at two sites over a period of 1 to 1/3 martian years. The complete set of 1044 optical depth determinations is presented in graphical and tabular form. Error estimates are presented in detail. Otpical depths in the morning (AM) are generally larger than in the afternoon (PM). The AM-PM differences are ascribed to condensation of water vapor into atmospheric ice aerosols at night and their evaporation in midday. A smoothed time series of these differences shows several seasonal peaks. These are simulated using a one-dimensional radiative convective model which predicts martial atmospheric temperature profiles. A calculation combinig these profiles with water vapor measurements from the Mars Atmospheric Water Detector is used to predict when the diurnal variations of water condensation should occur. The model reproduces a majority of the observed peaks and shows the factors influencing the process. Diurnal variation of condensation is shown to peak when the latitude and season combine to warm the atmosphere to the optimum temperature, cool enough to condense vapor at night and warm enough to cause evaporation at midday.
10. Absorption depth profile of water on thermoplastic starch films
SciTech Connect
Bonno, B.; Laporte, J.L.; Paris, D.; D'Leon, R.T.
2000-01-01
It is well known that petroleum derived polymers are primary environmental contaminants. The study of new packing biodegradable materials has been the object of numerous papers in past years. Some of these new materials are the thermoplastic films derived from wheat starch. In the present paper, the authors study some of properties of wheat starch thermoplastic films, with various amounts of absorbed water, using photoacoustic spectroscopy techniques. The absorption depth profile of water in the starch substrate is determined for samples having a variable water level.
11. THEMIS Observations of Atmospheric Aerosol Optical Depth
NASA Technical Reports Server (NTRS)
Smith, Michael D.; Bandfield, Joshua L.; Christensen, Philip R.; Richardson, Mark I.
2003-01-01
The Mars Odyssey spacecraft entered into Martian orbit in October 2001 and after successful aerobraking began mapping in February 2002 (approximately Ls=330 deg.). Images taken by the Thermal Emission Imaging System (THEMIS) on-board the Odyssey spacecraft allow the quantitative retrieval of atmospheric dust and water-ice aerosol optical depth. Atmospheric quantities retrieved from THEMIS build upon existing datasets returned by Mariner 9, Viking, and Mars Global Surveyor (MGS). Data from THEMIS complements the concurrent MGS Thermal Emission Spectrometer (TES) data by offering a later local time (approx. 2:00 for TES vs. approx. 4:00 - 5:30 for THEMIS) and much higher spatial resolution.
12. Absorption Optics of Aqueous Foams
Bandyopadhyay, Ranjini; Gittings, Alex; Durian, D. J.
2002-11-01
Aqueous foams are composed of gas bubbles packed together in a small volume of soapy water. The large number of gas-liquid interfaces in foams results in very strong scattering of light, which explains the opaque nature of conventional aqueous foams such as shaving foams and mousse. For dry foams, the interfaces can take the following three forms: the soap films where two bubbles meet, the triangular plateau borders where three soap films meet and the vertices where four plateau borders meet. Previous experiments have shown that most of the scattering occurs from the plateau borders 2,3 and the transport mean free path of light (l*), the bubble radius (R) and the liquid fraction of foam (epsilon) is related through the relation l*=R/(epsilon0.5). To understand the reflection and scattering of light at the gas-bubble interfaces, we study the absorption of photons in the liquid network as a function of the foam absorptivity. We do this to confirm if the time spent by the photons in the liquid phase is proportional to the liquid fraction of the foam. Our results indicate that for a specific range of liquid fractions (0.05 is less than e is less than 0.1), the photons seem to get trapped in the liquid network. This result is independent of the absorptivity of the foam and leads us to conclude that under appropriate conditions, an aqueous foam behaves very much like an optical fiber network. Aqueous foam is generated in the lab by the method of turbulent mixing of N2 gas with a jet of alpha-olefin-sulfonate (AOS) solution. The foam has been made absorbing by dissolving small quantities of rhodamine dye (R = 0.005 g/l, R = 0.01 g/l and R = 0.0124 g/l) in the AOS solution. The transmission of photons through the foams of liquid fractions 0.0297 is less than e is less than 0.35 has been studied using Diffuse Transmission Spectroscopy (DTS). For each liquid fraction, the transport mean free path l* (the length over which the photon travels before it gets completely
13. Aerosol optical depth retrievals over the Konza Prairie
NASA Technical Reports Server (NTRS)
Bruegge, Carol J.; Halthore, Rangasayi N.; Markham, Brian; Spanner, Michael; Wrigley, Robert
1992-01-01
The aerosol optical depth over the Konza Prairie, near Manhattan, Kansas, was recorded at various locations by five separate teams. These measurements were made in support of the First ISLSCP Field Experiment (FIFE) and used to correct imagery from a variety of satellite and aircraft sensors for the effects of atmospheric scattering and absorption. The results from one instrument are reported here for 26 days in 1987 and for 7 in 1989. Daily averages span a range of 0.05 to 0.28 in the midvisible wavelengths. In addition, diurnal variations are noted in which the afternoon optical depths are greater than those of the morning by as much as 0.07. A comparison between instruments and processing techniques used to determine these aerosol optical depths is provided. The first comparisons are made using summer 1987 data. Differences of as much as 0.05 (midvisible) are observed. Although these data allow reasonable surface reflectance retrievals, they do not agree to within the performance limits typically associated with these types of instruments. With an accuracy goal of 0.02 a preseason calibration/comparison experiment was conducted at a mountain site prior to the final field campaign in 1989. Good calibration data were obtained, and good agreement (0.01, midvisible) was observed in the retrieved optical depth acquired over the Konza. By comparing data from the surface instruments at different locations, spatial inhomogeneities are determined. Then, data from the airborne tracking sunphotometer allow one to determine variations as a function of altitude. Finally, a technique is proposed for using the in situ data to establish an instrument calibration.
14. RANDOM WALKS AND EFFECTIVE OPTICAL DEPTH IN RELATIVISTIC FLOW
SciTech Connect
Shibata, Sanshiro; Tominaga, Nozomu; Tanaka, Masaomi
2014-05-20
We investigate the random walk process in relativistic flow. In the relativistic flow, photon propagation is concentrated in the direction of the flow velocity due to the relativistic beaming effect. We show that in the pure scattering case, the number of scatterings is proportional to the size parameter ξ ≡ L/l {sub 0} if the flow velocity β ≡ v/c satisfies β/Γ >> ξ{sup –1}, while it is proportional to ξ{sup 2} if β/Γ << ξ{sup –1}, where L and l {sub 0} are the size of the system in the observer frame and the mean free path in the comoving frame, respectively. We also examine the photon propagation in the scattering and absorptive medium. We find that if the optical depth for absorption τ{sub a} is considerably smaller than the optical depth for scattering τ{sub s} (τ{sub a}/τ{sub s} << 1) and the flow velocity satisfies β≫√(2τ{sub a}/τ{sub s}), then the effective optical depth is approximated by τ{sub *} ≅ τ{sub a}(1 + β)/β. Furthermore, we perform Monte Carlo simulations of radiative transfer and compare the results with the analytic expression for the number of scatterings. The analytic expression is consistent with the results of the numerical simulations. The expression derived in this study can be used to estimate the photon production site in relativistic phenomena, e.g., gamma-ray burst and active galactic nuclei.
15. Sensitivity of depth of maximum and absorption depth of EAS to hadron production mechanism
NASA Technical Reports Server (NTRS)
Antonov, R. A.; Ivanenko, I. P.; Kanevsky, B. L.; Kuzmin, V. A.; Galkin, V. I.; Hein, L. A.
1985-01-01
Comparison of experimental data on depth of extensive air showers (EAS) development maximum in the atmosphere, T sub M and path of absorption, lambda, in the lower atmosphere of EAS with fixed particle number in the energy region eV with the results of calculation show that these parameters are sensitive mainly to the inelastic interaction cross section and scaling violation in the fragmentation and pionization region. The data are explained in a unified manner within the framework of a model in which scaling is violated slightly in the fragmentation region and strongly in the pionization region at primary cosmic rays composition close to the normal one and a permanent increase of inelastic interaction cross section. It is shown that, while interpreting the experimental data, disregard of two methodical points causes a systematic shift in T sub M: (1) shower selection system; and (2) EAS electron lateral distribution when performing the calculations on basis of which the transfer is made from the Cerenkov pulse FWHM to the depth of shower maximum, T sub M.
16. Ocean optics estimation for absorption, backscattering, and phase function parameters.
PubMed
Hakim, Ammar H; McCormick, Norman J
2003-02-20
We propose and test an inverse ocean optics procedure with numerically simulated data for the determination of inherent optical properties using in-water radiance measurements. If data are available at only one depth within a deep homogeneous water layer, then the single-scattering albedo and the single parameter that characterizes the Henyey-Greenstein phase function can be estimated. If data are available at two depths, then these two parameters can be determined along with the optical thickness so that the absorption and scattering coefficients, and also the backscattering coefficient, can be estimated. With a knowledge of these parameters, the albedo and Lambertian fraction of reflected radiance of the bottom can be determined if measurements are made close to the bottom. A simplified method for determining the optical properties of the water also is developed for only three irradiance-type measurements if the radiance is approximately in the asymptotic regime. PMID:12617207
17. Geometrical interpretation of optical absorption
SciTech Connect
Monzon, J. J.; Barriuso, A. G.; Sanchez-Soto, L. L.; Montesinos-Amilibia, J. M.
2011-08-15
We reinterpret the transfer matrix for an absorbing system in very simple geometrical terms. In appropriate variables, the system appears as performing a Lorentz transformation in a (1 + 3)-dimensional space. Using homogeneous coordinates, we map that action on the unit sphere, which is at the realm of the Klein model of hyperbolic geometry. The effects of absorption appear then as a loxodromic transformation, that is, a rhumb line crossing all the meridians at the same angle.
18. Smoke optical depths - Magnitude, variability, and wavelength dependence
NASA Technical Reports Server (NTRS)
Pueschel, R. F.; Russell, P. B.; Colburn, D. A.; Ackerman, T. P.; Allen, D. A.
1988-01-01
An airborne autotracking sun-photometer has been used to measure magnitudes, temporal/spatial variabilities, and the wavelength dependence of optical depths in the near-ultraviolet to near-infrared spectrum of smoke from two forest fires and one jet fuel fire and of background air. Jet fuel smoke optical depths were found to be generally less wavelength dependent than background aerosol optical depths. Forest fire smoke optical depths, however, showed a wide range of wavelength depedences, such as incidents of wavelength-independent extinction.
19. Improved evaluation of optical depth components from Langley plot data
NASA Technical Reports Server (NTRS)
Biggar, S. F.; Gellman, D. I.; Slater, P. N.
1990-01-01
A simple, iterative procedure to determine the optical depth components of the extinction optical depth measured by a solar radiometer is presented. Simulated data show that the iterative procedure improves the determination of the exponent of a Junge law particle size distribution. The determination of the optical depth due to aerosol scattering is improved as compared to a method which uses only two points from the extinction data. The iterative method was used to determine spectral optical depth components for June 11-13, 1988 during the MAC III experiment.
20. Further advancement of differential optical absorption spectroscopy: theory of orthogonal optical absorption spectroscopy.
PubMed
Liudchik, Alexander M
2014-08-10
A modified version of the differential optical absorption spectroscopy (DOAS) method is presented. The technique is called orthogonal optical absorption spectroscopy (OOAS). A widespread variant of DOAS with smoothing of the registered spectrum and absorption cross sections being made employing a polynomial regression is a particular case of OOAS. The concept of OOAS provides a variety of new possibilities for constructing computational schemes and analyzing the influence of different error sources on calculated concentrations. PMID:25320931
1. Single-molecule imaging by optical absorption
Celebrano, Michele; Kukura, Philipp; Renn, Alois; Sandoghdar, Vahid
2011-02-01
To date, optical studies of single molecules at room temperature have relied on the use of materials with high fluorescence quantum yield combined with efficient spectral rejection of background light. To extend single-molecule studies to a much larger pallet of substances that absorb but do not fluoresce, scientists have explored the photothermal effect, interferometry, direct attenuation and stimulated emission. Indeed, very recently, three groups have succeeded in achieving single-molecule sensitivity in absorption. Here, we apply modulation-free transmission measurements known from absorption spectrometers to image single molecules under ambient conditions both in the emissive and strongly quenched states. We arrive at quantitative values for the absorption cross-section of single molecules at different wavelengths and thereby set the ground for single-molecule absorption spectroscopy. Our work has important implications for research ranging from absorption and infrared spectroscopy to sensing of unlabelled proteins at the single-molecule level.
2. Optical and thermal depth profile reconstructions of inhomogeneous photopolymerization in dental resins using photothermal waves
Martínez-Torres, P.; Mandelis, A.; Alvarado-Gil, J. J.
2010-09-01
Photopolymerization is a process that depends, among other factors, on the optical properties of polymerized materials. In turn, this process affects longitudinal light transport in these materials, thereby altering their optical absorption coefficient which is thus expected to exhibit depth dependence. Furthermore, polymerization affects the thermal properties of these materials. A robust theoretical approach to the study of the depth-dependent optical absorption coefficient, β(x ), and thermal diffusivity, α(x ), in materials exhibiting depth profiles of these parameters has been developed through the photothermal inverse problem based on the concept of the thermal-harmonic oscillator. Using this concept in the frequency-domain nonhomogeneous photothermal-wave boundary-value problem, the simultaneous reconstruction of arbitrary simultaneous optical and thermal depth profiles was achieved using a multiparameter fitting method to the experimental amplitude and phase. As a first application of the theory to partially polymerized Alert Composite (shade A3) dental resin, with curing induced by a blue light-emitting diode, the β(x ) and α(x ) depth profiles were reconstructed from photothermal radiometric frequency-scanned data. A strong anticorrelation of these two depth profiles was observed and was interpreted in terms of photochemical processes occurring during the optical (photocuring) creation of long polymeric chains in the resin. The photothermally reconstructed depth profiles may have implications for the optimization of blue light curing methods using such resins in dental clinical practice.
3. Coherent perfect absorption in nonlinear optics
Zheng, Yuanlin; Wan, Wenjie; Chen, Xianfeng
2013-02-01
Recently, a concept of time reversed lasing or coherent perfect absorber (CPA) has been proposed by A. D. Stone and co-workers, and was shortly experimentally demonstrated by them. The CPA system is illuminated coherently and monochromatically by the time reverse of the output of a lasing mode and the incident radiation is perfectly absorbed. Shortly afterwards, Stefano Longhi extended the idea to realize a CPA for colored incident light, and have theoretically shown that the time reversal of optical parametric oscillation (OPO) in a nonlinear medium could also realize a colored CPA for incident signal and idler fields which can be seemed as a kind of nonlinear CPA. Here we present the realization of such time-reversed processes in nonlinear optics regime, including time-reversed second harmonic generation (SHG) for coherent absorption at harmonic frequency of the pump and time-reversed optical parametric amplification (OPA) for coherent attenuation of colored travelling optical fields. Time reversed SHG is carried out at both phase matching and mismatching conditions, which shows parametric near perfect absorption at the harmonic frequency of the pump. The time reversal of OPA is demonstrated experimentally in a nonlinear medium to form a coherent absorber for perpendicularly polarized signal and idler travelling waves, realizing in the condition of OPA by a type II phase matching scheme. The absorption of signal/idler pair occurs at some specific phase difference. This is the first experimental demonstration of coherent absorption processes in nonlinear optics regime.
4. Spectral Absorption Depth Profile: A Step Forward to Plasmonic Solar Cell Design
Hossain, Mohammad K.; Mukhaimer, Ayman W.; Drmosh, Qasem A.
2016-07-01
Absorption depth profile, a deterministic and key factor that defines the quality of excitons generation rate in optoelectronic devices, is numerically predicted using finite different time domain analysis. A typical model, nanoparticles array on silicon slab, was devised considering the concept of plasmonic solar cell design. The trend of spectral absorption depth profile distributions at various wavelengths of the solar spectrum, 460 nm, 540 nm, 650 nm, 815 nm, and 1100 nm, was obtained. A stronger and well-distributed absorption profile was obtained at ˜650 nm of the solar spectrum (i.e. ˜1.85 eV, c-Si bandgap), although the absorbing layer was affected more than a half micron depth at shorter wavelengths. Considering the observations obtained from this simulation, we have shown a simple two-step method in fabricating ultra-pure silver (Ag) nanoparticles that can be used as plasmonic nanoscatterers in a thin film solar cell. The morphology and elemental analysis of as-fabricated Ag nanoparticles was confirmed by field emission scanning electron microscope (FESEM) and FESEM-coupled electron diffraction spectroscopy. The size of the as-fabricated Ag nanoparticles was found to range from 50 nm to 150 nm in diameter. Further investigations on structural and optical properties of the as-fabricated specimen were carried out using ultraviolet-visible (UV-Vis) absorption, photoluminesce, and x-ray diffraction (XRD). Preferential growth of ZnO along {002} was confirmed by XRD pattern that was more intense and broadened at increasing annealing temperatures. The lattice parameter c was found to increase, whereas grain size increased with increasing annealing temperature. The optical bandgap was also observed to decrease from 3.31 eV to 3.25 eV at increasing annealing temperatures through UV-Vis measurements. This parallel investigation on optical properties by simulation is in line with experimental studies and, in fact, facilitates devising optimum process cost for
5. Microwave and optical saturable absorption in graphene.
PubMed
Zheng, Zhiwei; Zhao, Chujun; Lu, Shunbin; Chen, Yu; Li, Ying; Zhang, Han; Wen, Shuangchun
2012-10-01
We report on the first experiments on saturable absorption in graphene at microwave frequency band. Almost independent of the incident frequency, microwave absorbance of graphene always decreases with increasing the power and reaches at a constant level for power larger than 80 µW, evidencing the microwave saturable absorption property of graphene. Optical saturable absorption of the same graphene sample was also experimentally confirmed by an open-aperture Z-scan technique by one laser at telecommunication band and another pico-second laser at 1053 nm, respectively. Herein, we are able to conclude that graphene is indeed a broadband saturable absorber that can operate at both microwave and optical band. PMID:23188285
6. Calculation of optical depths from an integral of the Voigt function
NASA Technical Reports Server (NTRS)
Milman, A. S.
1978-01-01
The optical depth along a vertical path in an atmosphere in hydrostatic equilibrium can be calculated from an integral of the Voigt function for the case where the absorption is due to spectral lines. Series expansions are presented that allow rapid evaluation of this integral over all values of the independent variables, frequency and pressure.
7. LINKING Lyα AND LOW-IONIZATION TRANSITIONS AT LOW OPTICAL DEPTH
SciTech Connect
Jaskot, A. E.; Oey, M. S.
2014-08-20
We suggest that low optical depth in the Lyman continuum (LyC) may relate the Lyα emission, C II and Si II absorption, and C II* and Si II* emission seen in high-redshift galaxies. We base this analysis on Hubble Space Telescope Cosmic Origins Spectrograph spectra of four Green Pea (GP) galaxies, which may be analogs of z > 2 Lyα emitters (LAEs). In the two GPs with the strongest Lyα emission, the Lyα line profiles show reduced signs of resonant scattering. Instead, the Lyα profiles resemble the Hα line profiles of evolved star ejecta, suggesting that the Lyα emission originates from a low column density and similar outflow geometry. The weak C II absorption and presence of non-resonant C II* emission in these GPs support this interpretation and imply a low LyC optical depth along the line of sight. In two additional GPs, weak Lyα emission and strong C II absorption suggest a higher optical depth. These two GPs differ in their Lyα profile shapes and C II* emission strengths, however, indicating different inclinations of the outflows to our line of sight. With these four GPs as examples, we explain the observed trends linking Lyα, C II, and C II* in stacked LAE spectra, in the context of optical depth and geometric effects. Specifically, in some galaxies with strong Lyα emission, a low LyC optical depth may allow Lyα to escape with reduced scattering. Furthermore, C II absorption, C II* emission, and Lyα profile shape can reveal the optical depth, constrain the orientation of neutral outflows in LAEs, and identify candidate LyC emitters.
8. Microphysical and Dynamical Influences on Cirrus Cloud Optical Depth Distributions
SciTech Connect
Kay, J.; Baker, M.; Hegg, D.
2005-03-18
Cirrus cloud inhomogeneity occurs at scales greater than the cirrus radiative smoothing scale ({approx}100 m), but less than typical global climate model (GCM) resolutions ({approx}300 km). Therefore, calculating cirrus radiative impacts in GCMs requires an optical depth distribution parameterization. Radiative transfer calculations are sensitive to optical depth distribution assumptions (Fu et al. 2000; Carlin et al. 2002). Using raman lidar observations, we quantify cirrus timescales and optical depth distributions at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site in Lamont, OK (USA). We demonstrate the sensitivity of outgoing longwave radiation (OLR) calculations to assumed optical depth distributions and to the temporal resolution of optical depth measurements. Recent work has highlighted the importance of dynamics and nucleation for cirrus evolution (Haag and Karcher 2004; Karcher and Strom 2003). We need to understand the main controls on cirrus optical depth distributions to incorporate cirrus variability into model radiative transfer calculations. With an explicit ice microphysics parcel model, we aim to understand the influence of ice nucleation mechanism and imposed dynamics on cirrus optical depth distributions.
9. Aerosol optical absorption measurements with photoacoustic spectroscopy
Liu, Kun; Wang, Lei; Liu, Qiang; Wang, Guishi; Tan, Tu; Zhang, Weijun; Chen, Weidong; Gao, Xiaoming
2015-04-01
Many parameters related to radiative forcing in climate research are known only with large uncertainties. And one of the largest uncertainties in global radiative forcing is the contribution from aerosols. Aerosols can scatter or absorb the electromagnetic radiation, thus may have negative or positive effects on the radiative forcing of the atmosphere, respectively [1]. And the magnitude of the effect is directly related to the quantity of light absorbed by aerosols [2,3]. Thus, sensitivity and precision measurement of aerosol optical absorption is crucial for climate research. Photoacoustic spectroscopy (PAS) is commonly recognized as one of the best candidates to measure the light absorption of aerosols [4]. A PAS based sensor for aerosol optical absorption measurement was developed. A 532 nm semiconductor laser with an effective power of 160 mW was used as a light source of the PAS sensor. The PAS sensor was calibrated by using known concentration NO2. The minimum detectable optical absorption coefficient (OAC) of aerosol was determined to be 1 Mm-1. 24 hours continues measurement of OAC of aerosol in the ambient air was carried out. And a novel three wavelength PAS aerosol OAC sensor is in development for analysis of aerosol wavelength-dependent absorption Angstrom coefficient. Reference [1] U. Lohmann and J. Feichter, Global indirect aerosol effects: a review, Atmos. Chem. Phys. 5, 715-737 (2005) [2] M. Z. Jacobson, Strong radiative heating due to the mixing state of black carbon in atmospheric aerosols, Nature 409, 695-697 (2001) [3] V. Ramanathan and G. Carmichae, Global and regional climate changes due to black carbon, nature geoscience 1, 221-227 (2008) [4] W.P Arnott, H. Moosmuller, C. F. Rogers, T. Jin, and R. Bruch, Photoacoustic spectrometer for measuring light absorption by aerosol: instrument description. Atmos. Environ. 33, 2845-2852 (1999).
10. Depth
PubMed Central
Koenderink, Jan J; van Doorn, Andrea J; Wagemans, Johan
2011-01-01
Depth is the feeling of remoteness, or separateness, that accompanies awareness in human modalities like vision and audition. In specific cases depths can be graded on an ordinal scale, or even measured quantitatively on an interval scale. In the case of pictorial vision this is complicated by the fact that human observers often appear to apply mental transformations that involve depths in distinct visual directions. This implies that a comparison of empirically determined depths between observers involves pictorial space as an integral entity, whereas comparing pictorial depths as such is meaningless. We describe the formal structure of pictorial space purely in the phenomenological domain, without taking recourse to the theories of optics which properly apply to physical space—a distinct ontological domain. We introduce a number of general ways to design and implement methods of geodesy in pictorial space, and discuss some basic problems associated with such measurements. We deal mainly with conceptual issues. PMID:23145244
11. Depth-resolved photothermal optical coherence tomography by local optical path length change measurement (Conference Presentation)
Makita, Shuichi; Hong, Young-Joo; Li, En; Yasuno, Yoshiaki
2016-03-01
Photothermal OCT has been emerged to contrast absorbers in biological tissues. The tissues response to photothermal excitation as change of thermal strain and refractive index. To resolve the depth of absorption agents, the measurements of the local thermal strain change and local refractive index change due to photothermal effect is required. In this study, we developed photothermal OCT for depth-resolved absorption contrast imaging. The phase-resolved OCT can measure the axial strain change and local refractive index change as local optical path length change. A swept-source OCT system is used with a wavelength swept laser at 1310 nm with a scanning rate of 50 kHz. The sensitivity of 110 dB is achieved. At the sample arm, the excitation beam from a fiber-coupled laser diode of 406 nm wavelength is combined with the OCT probe beam co-linearly. The slowly modulated excitation beam around 300 Hz illuminate biological tissues. M-mode scan is applied during one-period modulation duration. The local optical path length change is measured by temporal and axial phase difference. The theoretical prediction of the photothermal response is derived and in good agreement with experimental results. In the case of slow modulation, the delay of photothermal response can be neglected. The local path length changes are averaged over the half period of the excitation modulation, and then demodulated. This method exhibits 3-dB gain in the sensitivity of the local optical path length change measurement over the direct Fourier transform method. In vivo human skin imaging of endogenous absorption agent will be demonstrated.
12. Aerosol Optical Depth Value-Added Product Report
SciTech Connect
Koontz, A; Hodges, G; Barnard, J; Flynn, C; Michalsky, J
2013-03-17
This document describes the process applied to retrieve aerosol optical depth (AOD) from multifilter rotating shadowband radiometers (MFRSR) and normal incidence multifilter radiometers (NIMFR) operated at the ARM Climate Research Facility’s ground-based facilities.
13. Aerosol spectral optical depths - Jet fuel and forest fire smokes
NASA Technical Reports Server (NTRS)
Pueschel, R. F.; Livingston, J. M.
1990-01-01
The Ames autotracking airborne sun photometer was used to investigate the spectral depth between 380 and 1020 nm of smokes from a jet fuel pool fire and a forest fire in May and August 1988, respectively. Results show that the forest fire smoke exhibited a stronger wavelength dependence of optical depths than did the jet fuel fire smoke at optical depths less than unity. At optical depths greater than or equal to 1, both smokes showed neutral wavelength dependence, similar to that of an optically thin stratus deck. These results verify findings of earlier investigations and have implications both on the climatic impact of large-scale smokes and on the wavelength-dependent transmission of electromagnetic signals.
14. Towards Improved Cirrus Cloud Optical Depths from CALIPSO
Garnier, Anne; Vaughan, Mark; Pelon, Jacques; Winker, David; Trepte, Chip; Young, Stuart
2016-06-01
This paper reviews recent advances regarding the retrieval of optical depths of semi-transparent cirrus clouds using synergetic analyses of perfectly collocated observations from the CALIOP lidar and the IIR infrared radiometer aboard the CALIPSO satellite.
15. Linear and nonlinear optical absorption coefficients of spherical dome shells
Guo, Kangxian; Liu, Guanghui; Huang, Lu; Zheng, Xianyi
2015-08-01
Linear and nonlinear optical absorption coefficients of spherical dome shells are theoretically investigated within analytical wave functions and numerical quantized energy levels. Our results show that the inner radius, the outer radius and the cut-off angle of spherical dome shells have great influences on linear and nonlinear optical absorption coefficients as well as the total optical absorption coefficients. It is found that with the increase of the inner radius and the outer radius, linear and nonlinear optical absorption coefficients exhibit a blueshift and a redshift, respectively. However, with the increase of the cut-off angle, linear and nonlinear optical absorption coefficients do not shift. Besides, the resonant peaks of linear and nonlinear optical absorption coefficients climb up and then decrease with increasing the cut-off angle. The influences of the incident optical intensity on the total optical absorption coefficients are studied. It is found that the bleaching effect occurs at higher incident optical intensity.
16. Depth-encoded synthetic aperture optical coherence tomography of biological tissues with extended focal depth.
PubMed
Mo, Jianhua; de Groot, Mattijs; de Boer, Johannes F
2015-02-23
Optical coherence tomography (OCT) has proven to be able to provide three-dimensional (3D) volumetric images of scattering biological tissues for in vivo medical diagnostics. Unlike conventional optical microscopy, its depth-resolving ability (axial resolution) is exclusively determined by the laser source and therefore invariant over the full imaging depth. In contrast, its transverse resolution is determined by the objective's numerical aperture and the wavelength which is only approximately maintained over twice the Rayleigh range. However, the prevailing laser sources for OCT allow image depths of more than 5 mm which is considerably longer than the Rayleigh range. This limits high transverse resolution imaging with OCT. Previously, we reported a novel method to extend the depth-of-focus (DOF) of OCT imaging in Mo et al.Opt. Express 21, 10048 (2013)]. The approach is to create three different optical apertures via pupil segmentation with an annular phase plate. These three optical apertures produce three OCT images from the same sample, which are encoded to different depth positions in a single OCT B-scan. This allows for correcting the defocus-induced curvature of wave front in the pupil so as to improve the focus. As a consequence, the three images originating from those three optical apertures can be used to reconstruct a new image with an extended DOF. In this study, we successfully applied this method for the first time to both an artificial phantom and biological tissues over a four times larger depth range. The results demonstrate a significant DOF improvement, paving the way for 3D high resolution OCT imaging beyond the conventional Rayleigh range. PMID:25836528
17. Depth profilometry via multiplexed optical high-coherence interferometry.
PubMed
2015-01-01
Depth Profilometry involves the measurement of the depth profile of objects, and has significant potential for various industrial applications that benefit from non-destructive sub-surface profiling such as defect detection, corrosion assessment, and dental assessment to name a few. In this study, we investigate the feasibility of depth profilometry using an Multiplexed Optical High-coherence Interferometry MOHI instrument. The MOHI instrument utilizes the spatial coherence of a laser and the interferometric properties of light to probe the reflectivity as a function of depth of a sample. The axial and lateral resolutions, as well as imaging depth, are decoupled in the MOHI instrument. The MOHI instrument is capable of multiplexing interferometric measurements into 480 one-dimensional interferograms at a location on the sample and is built with axial and lateral resolutions of 40 μm at a maximum imaging depth of 700 μm. Preliminary results, where a piece of sand-blasted aluminum, an NBK7 glass piece, and an optical phantom were successfully probed using the MOHI instrument to produce depth profiles, demonstrate the feasibility of such an instrument for performing depth profilometry. PMID:25803289
18. Depth Profilometry via Multiplexed Optical High-Coherence Interferometry
PubMed Central
2015-01-01
Depth Profilometry involves the measurement of the depth profile of objects, and has significant potential for various industrial applications that benefit from non-destructive sub-surface profiling such as defect detection, corrosion assessment, and dental assessment to name a few. In this study, we investigate the feasibility of depth profilometry using an Multiplexed Optical High-coherence Interferometry MOHI instrument. The MOHI instrument utilizes the spatial coherence of a laser and the interferometric properties of light to probe the reflectivity as a function of depth of a sample. The axial and lateral resolutions, as well as imaging depth, are decoupled in the MOHI instrument. The MOHI instrument is capable of multiplexing interferometric measurements into 480 one-dimensional interferograms at a location on the sample and is built with axial and lateral resolutions of 40 μm at a maximum imaging depth of 700 μm. Preliminary results, where a piece of sand-blasted aluminum, an NBK7 glass piece, and an optical phantom were successfully probed using the MOHI instrument to produce depth profiles, demonstrate the feasibility of such an instrument for performing depth profilometry. PMID:25803289
19. Optical absorption spectra of dications of carotenoids
SciTech Connect
Jeevarajan, J.A.; Wei, C.C.; Jeevarajan, A.S.; Kispert, L.D.
1996-04-04
Quantitative optical absorption spectra of the cation radicals and the dications of canthaxanthin (I), {beta}carotene (II), 7-cyano-7-ethoxycarbonyl-7-apo-{beta}-carotene (III), and 7,7-dimethyl-7-apo-{beta}-carotene (IV) in dichloromethane solution are reported. Exclusive formation of dications occurs when the carotenoids are oxidized with ferric chloride. Addition of neutral carotenoid to the dications results in equilibrium formation of cation radicals. Oxidation with iodine in dichloromethane affords only cation radicals; electrochemical oxidation under suitable conditions yields both dications and cation radicals. Values of the optical parameters depend on the nature of the oxidative medium. The oscillator strengths calculated for gas phase cation radicals and dications of I-IV using the INDO/S method show the same trend as the experimental values. 31 refs., 4 figs., 2 tabs.
20. Aerosol optical depth determination from ground based irradiance ratios
SciTech Connect
Miller, J. R.; O'Neill, N. T.; Boyer, A.
1989-08-01
The atmospheric optical depth serves as an input parameter to atmospheric correction procedures in remote sensing and as an index of atmospheric opacity or constituent columnar abundance for meteorological applications. Its measurement, typically performed by means of a small field of view radiometer centered on the solar disk, is sensitive to the absolute calibration accuracy of the instrument. In this paper a simple technique is presented which permits the extraction of aerosol optical depth from the ratio of total to direct irradiance measurements. An error analysis performed on the results of radiative transfer simulations and field measurements indicates that the technique generates values of aerosol optical depth which are sufficiently accurate for many applications. This method thus represents a useful alternative to standard sunphotometer measurements.
1. Validation of MODIS Aerosol Optical Depth Retrieval Over Land
NASA Technical Reports Server (NTRS)
Chu, D. A.; Kaufman, Y. J.; Ichoku, C.; Remer, L. A.; Tanre, D.; Holben, B. N.; Einaudi, Franco (Technical Monitor)
2001-01-01
Aerosol optical depths are derived operationally for the first time over land in the visible wavelengths by MODIS (Moderate Resolution Imaging Spectroradiometer) onboard the EOSTerra spacecraft. More than 300 Sun photometer data points from more than 30 AERONET (Aerosol Robotic Network) sites globally were used in validating the aerosol optical depths obtained during July - September 2000. Excellent agreement is found with retrieval errors within (Delta)tau=+/- 0.05 +/- 0.20 tau, as predicted, over (partially) vegetated surfaces, consistent with pre-launch theoretical analysis and aircraft field experiments. In coastal and semi-arid regions larger errors are caused predominantly by the uncertainty in evaluating the surface reflectance. The excellent fit was achieved despite the ongoing improvements in instrument characterization and calibration. This results show that MODIS-derived aerosol optical depths can be used quantitatively in many applications with cautions for residual clouds, snow/ice, and water contamination.
2. Dual focus diffractive optical element with extended depth of focus
Uno, Katsuhiro; Shimizu, Isao
2014-09-01
A dual focus property and an extended depth of focus were verified by a new type of diffractive lens displaying on liquid crystal on silicon (LCoS) devices. This type of lens is useful to read information on multilayer optical discs and tilted discs. The radial undulation of the phase groove on the diffractive lens gave the dual focus nature. The focal extension was performed by combining the dual focus lens with the axilens that was invented for expanding the depth of focus. The number of undulations did not affect the intensity along the optical axis but the central spot of the diffraction pattern.
3. Comment: On the different approaches of Rayleigh optical depth determination
Eberhard, Wynn L.
2010-07-01
Srivastava et al. (2009) presented Rayleigh scattering cross-sections and optical depths for Earth's atmosphere that are approximately 3% smaller than previously accepted. Their analysis was based on quantum-mechanical theory for anisotropic scattering in the Cabannes line published in papers that seem to have introduced some confusion about determining the anisotropy and King factors. This comment clarifies these factors and shows that including the frequency-shifted rotational Raman lines gives the traditional King factor and the correct Rayleigh scattering for the optical depth.
4. A quantitative assessment of the depth sensitivity of an optical topography system using a solid dynamic tissue-phantom.
PubMed
Correia, Teresa; Banga, Anil; Everdell, N L; Gibson, Adam P; Hebden, Jeremy C
2009-10-21
A solid dynamic phantom with tissue-like optical properties is presented, which contains seven discrete targets impregnated with thermochromic pigment located at different depths from the surface. Changes in absorption are obtained in response to localized heating of the targets, simulating haemodynamic changes occurring in the brain and other tissues. The depth sensitivity of a continuous wave optical topography system was assessed successfully using the phantom. Images of the targets have been reconstructed using a spatially variant regularization, and the determined spatial localization in the depth direction is shown to be accurate within an uncertainty of about 3 mm down to a depth of about 30 mm. PMID:19794240
5. A quantitative assessment of the depth sensitivity of an optical topography system using a solid dynamic tissue-phantom
Correia, Teresa; Banga, Anil; Everdell, N. L.; Gibson, Adam P.; Hebden, Jeremy C.
2009-10-01
A solid dynamic phantom with tissue-like optical properties is presented, which contains seven discrete targets impregnated with thermochromic pigment located at different depths from the surface. Changes in absorption are obtained in response to localized heating of the targets, simulating haemodynamic changes occurring in the brain and other tissues. The depth sensitivity of a continuous wave optical topography system was assessed successfully using the phantom. Images of the targets have been reconstructed using a spatially variant regularization, and the determined spatial localization in the depth direction is shown to be accurate within an uncertainty of about 3 mm down to a depth of about 30 mm.
6. Periodically Diameter-Modulated Semiconductor Nanowires for Enhanced Optical Absorption.
PubMed
Ko, Minjee; Baek, Seong-Ho; Song, Bokyung; Kang, Jang-Won; Kim, Shin-Ae; Cho, Chang-Hee
2016-04-01
A diameter-modulated silicon nanowire array to enhance the optical absorption across broad spectral range is presented. Periodic shape engineering is achieved using conventional semiconductor processes and the unique optical properties are analyzed. The periodicity in the diameter of the silicon nanowires enables stronger and more closely spaced optical resonances, leading to broadband absorption enhancement. PMID:26833855
7. Linking Lyα and Low-ionization Transitions at Low Optical Depth
Jaskot, A. E.; Oey, M. S.
2014-08-01
We suggest that low optical depth in the Lyman continuum (LyC) may relate the Lyα emission, C II and Si II absorption, and C II* and Si II* emission seen in high-redshift galaxies. We base this analysis on Hubble Space Telescope Cosmic Origins Spectrograph spectra of four Green Pea (GP) galaxies, which may be analogs of z > 2 Lyα emitters (LAEs). In the two GPs with the strongest Lyα emission, the Lyα line profiles show reduced signs of resonant scattering. Instead, the Lyα profiles resemble the Hα line profiles of evolved star ejecta, suggesting that the Lyα emission originates from a low column density and similar outflow geometry. The weak C II absorption and presence of non-resonant C II* emission in these GPs support this interpretation and imply a low LyC optical depth along the line of sight. In two additional GPs, weak Lyα emission and strong C II absorption suggest a higher optical depth. These two GPs differ in their Lyα profile shapes and C II* emission strengths, however, indicating different inclinations of the outflows to our line of sight. With these four GPs as examples, we explain the observed trends linking Lyα, C II, and C II* in stacked LAE spectra, in the context of optical depth and geometric effects. Specifically, in some galaxies with strong Lyα emission, a low LyC optical depth may allow Lyα to escape with reduced scattering. Furthermore, C II absorption, C II* emission, and Lyα profile shape can reveal the optical depth, constrain the orientation of neutral outflows in LAEs, and identify candidate LyC emitters. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs GO-13293 and GO-12928.
8. Mirage effect spectrometry and light profile microscopy: Two views of an optical depth profile (abstract)
Power, J. F.; Fu, S. W.; Nepotchatykh, O. V.
2003-01-01
Photothermal depth profiling techniques are well adapted for the inspection of optically absorbing features on the length scale of 1-100 μm in a variety of media. However, the depth profiling mechanism intrinsic to thermal wave imaging is inherently ill posed [J. F. Power, AIP Conf. Proc. 463, 3 (1999)], and suffers obvious disadvantages such as sensitivity to experimental errors (requiring regularization) and subsurface broadening of the regularized depth profiles. Recently, through the introduction of light profile microscopy (LPM) an alternate method of optical inspection was made available for depth profiling optically absorbing, scattering, and luminescent structures on this length scale [J. F. Power and S. W. Fu, Appl. Spectros. 53, 1507 (1999); J. F. Power and S. W. Fu, U.S. Patent Pending]. LPM inspects a thin film under test by directing a laser beam through the material along the depth axis, parallel to a polished cross-sectional viewing surface. Luminescence and elastic scatter excited in the beam volume is imaged by a microscope aligned orthogonal to the beam axis. The images obtained by this method showed striking depth contrast in a variety of materials with subsurface interfaces and depth variations of luminescence yield. When implemented in dual beam mode [J. F. Power and S. W. Fu, U.S. Patent Pending; J. F. Power and S. W. Fu, (unpublished)] with an associated mathematical method, LPM may be used to quantitatively resolve depth variable optical absorption from light scattering and luminescence efficiency. In contrast to photothermal methods, the LPM technique is well posed. LPM was evaluated in tandem with mirage effect spectrometry (in normal deflection mode with bicell detection) [J. F. Power, S. W. Fu, and M. A. Schweitzer, Appl. Spectros. 54, 110 (2000)], to determine the effective use of each technique in analysis problems on complex materials. This study used samples with known depth variations of optical properties including homogeneous
9. A comparison of hydrographically and optically derived mixed layer depths
USGS Publications Warehouse
Zawada, D.G.; Zaneveld, J.R.V.; Boss, E.; Gardner, W.D.; Richardson, M.J.; Mishonov, A.V.
2005-01-01
Efforts to understand and model the dynamics of the upper ocean would be significantly advanced given the ability to rapidly determine mixed layer depths (MLDs) over large regions. Remote sensing technologies are an ideal choice for achieving this goal. This study addresses the feasibility of estimating MLDs from optical properties. These properties are strongly influenced by suspended particle concentrations, which generally reach a maximum at pycnoclines. The premise therefore is to use a gradient in beam attenuation at 660 nm (c660) as a proxy for the depth of a particle-scattering layer. Using a global data set collected during World Ocean Circulation Experiment cruises from 1988-1997, six algorithms were employed to compute MLDs from either density or temperature profiles. Given the absence of published optically based MLD algorithms, two new methods were developed that use c660 profiles to estimate the MLD. Intercomparison of the six hydrographically based algorithms revealed some significant disparities among the resulting MLD values. Comparisons between the hydrographical and optical approaches indicated a first-order agreement between the MLDs based on the depths of gradient maxima for density and c660. When comparing various hydrographically based algorithms, other investigators reported that inherent fluctuations of the mixed layer depth limit the accuracy of its determination to 20 m. Using this benchmark, we found a ???70% agreement between the best hydrographical-optical algorithm pairings. Copyright 2005 by the American Geophysical Union.
10. Eddington limit for a gaseous stratus with finite optical depth
Fukue, Jun
2015-06-01
The Eddington luminosity of a spherical source is usually defined for a uniformly extending normal plasma. We usually suppose that the gas can accrete to the central object at the sub-Eddington luminosity, while it would be blown off from the central luminous source in the super-Eddington case. We reconsider this central dogma of the Eddington limit under the radiative transfer effect for the purely scattering case, using analytical and numerical methods. For the translucent isolated gas cloud (stratus) with finite optical depth, the concept of the Eddington luminosity is drastically changed. In an heuristic way, we find that the critical condition is approximately expressed as Γ = (1 + μ* + τc)/2, where Γ (=L/LE) is the central luminosity L normalized by the Eddington luminosity LE, τc is the optical depth of the stratus, and μ* (=√{1-R_*^2/R^2}) is the direction cosine of the central object, R* being the radius of the central object, and R the distance from the central object. When the optical depth of the stratus is around unity, the classical Eddington limit roughly holds for the stratus; Γ ˜ 1. However, when the optical depth is greater than unity, the critical condition becomes roughly Γ ˜ τc/2, and the stratus would infall on to the central source even at the highly super-Eddington luminosity. When the optical depth is less than unity, on the other hand, the critical condition reduces to Γ ≳ (1 + μ*)/2, and the stratus could be blown off in some limited ranges, depending on μ*. This new concept of the Eddington limit for the isolated stratus could drastically change the accretion and outflow physics of highly inhomegeneous plasmas, with relevance for astrophysical jets and winds and supermassive black hole formation.
11. Structured illumination assisted microdeflectometry with optical depth scanning capability.
PubMed
Lu, Sheng-Huei; Hua, Hong
2016-09-01
Microdeflectometry is a powerful noncontact tool for measuring nanometer defects on a freeform surface. However, it requires a time-consuming process to take measurements at different depths for an extended depth of field (EDOF) and lacks surface information for integrating the measured gradient data to height. We propose an optical depth scanning technique to speed up the measurement process and introduce the structured illumination technique to efficiently determine the focused data among 3D observation and provide surface orientations for reconstructing an unknown surface shape. We demonstrated 3D measurements with an equivalent surface height sensitivity of 7.21 nm and an EDOF of at least 250 μm, which is 15 times that of the diffraction limited depth range. PMID:27607986
12. Absorption spectra and light penetration depth of normal and pathologically altered human skin
Barun, V. V.; Ivanov, A. P.; Volotovskaya, A. V.; Ulashchik, V. S.
2007-05-01
A three-layered skin model (stratum corneum, epidermis, and dermis) and engineering formulas for radiative transfer theory are used to study absorption spectra and light penetration depths of normal and pathologically altered skin. The formulas include small-angle and asymptotic approximations and a layer-addition method. These characteristics are calculated for wavelengths used for low-intensity laser therapy. We examined several pathologies such as vitiligo, edema, erythematosus lupus, and subcutaneous wound, for which the bulk concentrations of melanin and blood vessels or tissue structure (for subcutaneous wound) change compared with normal skin. The penetration depth spectrum is very similar to the inverted blood absorption spectrum. In other words, the depth is minimal at blood absorption maxima. The calculated absorption spectra enable the power and irradiation wavelength providing the required light effect to be selected. Relationships between the penetration depth and the diffuse reflectance coefficient of skin (unambiguously expressed through the absorption coefficient) are analyzed at different wavelengths. This makes it possible to find relationships between the light fields inside and outside the tissue.
13. Contrails of Small and Very Large Optical Depth
NASA Technical Reports Server (NTRS)
Atlas, David; Wang, Zhien
2010-01-01
This work deals with two kinds of contrails. The first comprises a large number of optically thin contrails near the tropopause. They are mapped geographically using a lidar to obtain their height and a camera to obtain azimuth and elevation. These high-resolution maps provide the local contrail geometry and the amount of optically clear atmosphere. The second kind is a single trail of unprecedentedly large optical thickness that occurs at a lower height. The latter was observed fortuitously when an aircraft moving along the wind direction passed over the lidar, thus providing measurements for more than 3 h and an equivalent distance of 620 km. It was also observed by Geostationary Operational Environmental Satellite (GOES) sensors. The lidar measured an optical depth of 2.3. The corresponding extinction coefficient of 0.023 per kilometer and ice water content of 0.063 grams per cubic meter are close to the maximum values found for midlatitude cirrus. The associated large radar reflectivity compares to that measured by ultrasensitive radar, thus providing support for the reality of the large optical depth.
14. Optical absorption in semiconductor nanorings under electric and magnetic fields
Zhang, Tong-Yi; Cao, Jun-Cheng; Zhao, Wei
2005-01-01
The optical absorption in semiconductor nanorings under a lateral DC field and a perpendicular magnetic field is numerically simulated by coherent wave approach. The exciton dominated optical absorption is compared with the free-carrier interband absorption to demonstrate the key role of Coulomb interaction between electron and hole. The influence of the lateral DC field and the perpendicular magnetic field on the optical absorption are discussed in detail. It shows that the lateral DC field can significantly enhance the Aharonov-Bohm effect of the neutral excitons in semiconductor nanorings.
15. High-resolution in-depth imaging of optically cleared thick samples using an adaptive SPIM
PubMed Central
Masson, Aurore; Escande, Paul; Frongia, Céline; Clouvel, Grégory; Ducommun, Bernard; Lorenzo, Corinne
2015-01-01
Today, Light Sheet Fluorescence Microscopy (LSFM) makes it possible to image fluorescent samples through depths of several hundreds of microns. However, LSFM also suffers from scattering, absorption and optical aberrations. Spatial variations in the refractive index inside the samples cause major changes to the light path resulting in loss of signal and contrast in the deepest regions, thus impairing in-depth imaging capability. These effects are particularly marked when inhomogeneous, complex biological samples are under study. Recently, chemical treatments have been developed to render a sample transparent by homogenizing its refractive index (RI), consequently enabling a reduction of scattering phenomena and a simplification of optical aberration patterns. One drawback of these methods is that the resulting RI of cleared samples does not match the working RI medium generally used for LSFM lenses. This RI mismatch leads to the presence of low-order aberrations and therefore to a significant degradation of image quality. In this paper, we introduce an original optical-chemical combined method based on an adaptive SPIM and a water-based clearing protocol enabling compensation for aberrations arising from RI mismatches induced by optical clearing methods and acquisition of high-resolution in-depth images of optically cleared complex thick samples such as Multi-Cellular Tumour Spheroids. PMID:26576666
16. High-resolution in-depth imaging of optically cleared thick samples using an adaptive SPIM
Masson, Aurore; Escande, Paul; Frongia, Céline; Clouvel, Grégory; Ducommun, Bernard; Lorenzo, Corinne
2015-11-01
Today, Light Sheet Fluorescence Microscopy (LSFM) makes it possible to image fluorescent samples through depths of several hundreds of microns. However, LSFM also suffers from scattering, absorption and optical aberrations. Spatial variations in the refractive index inside the samples cause major changes to the light path resulting in loss of signal and contrast in the deepest regions, thus impairing in-depth imaging capability. These effects are particularly marked when inhomogeneous, complex biological samples are under study. Recently, chemical treatments have been developed to render a sample transparent by homogenizing its refractive index (RI), consequently enabling a reduction of scattering phenomena and a simplification of optical aberration patterns. One drawback of these methods is that the resulting RI of cleared samples does not match the working RI medium generally used for LSFM lenses. This RI mismatch leads to the presence of low-order aberrations and therefore to a significant degradation of image quality. In this paper, we introduce an original optical-chemical combined method based on an adaptive SPIM and a water-based clearing protocol enabling compensation for aberrations arising from RI mismatches induced by optical clearing methods and acquisition of high-resolution in-depth images of optically cleared complex thick samples such as Multi-Cellular Tumour Spheroids.
17. Effect of depth order on linear vection with optical flows.
PubMed
Seya, Yasuhiro; Tsuji, Takayuki; Shinoda, Hiroyuki
2014-01-01
In the present study, the effects of depth order on forward and backward vection were examined using optical flows simulating motion in depth (i.e., approaching or receding). In an experiment, space extending 10 or 20 m in depth was simulated, and the space was divided into foreground and background spaces. In each space, a random-dot pattern was presented and the binocular disparity, size, and velocity of each dot were continuously manipulated in a way consistent with the depth being simulated. Participants reported whether they perceived vection. Latency, total duration (i.e., the amount of time that participants reported perceiving vection during a 60-s presentation), and strong-vection duration (i.e., the amount of time that participants reported perceiving strong vection) were measured. The results indicated that, even though the dots making up the optical flow were much smaller and slower moving in the background space than in the foreground space, vection was strongly dependent on flow motion in the background space. This supports the idea that the perceptual system uses background stimulus motion as a reliable cue for self-motion perception. PMID:25926971
18. Diurnal variations in optical depth at Mars: Observations and interpretations
NASA Technical Reports Server (NTRS)
Colburn, D. S.; Pollack, J. B.; Haberle, R. M.
1988-01-01
Viking lander camera images of the Sun were used to compute atmospheric optical depth at two sites over a period of 1 to 1/3 martian years. The complete set of 1044 optical depth determinations is presented in graphical and tabular form. Error estimates are presented in detail. Optical depths in the morning (AM) are generally larger than in the afternoon (PM). The AM-PM differences are ascribed to condensation of water vapor into atmospheric ice aerosols at night and their evaporation in midday. A smoothed time series of these differences shows several seasonal peaks. These are simulated using a one-dimensional radiative convective model which predicts martial atmospheric temperature profiles. A calculation combining these profiles with water vapor measurements from the Mars Atmospheric Water Detector is used to predict when the diurnal variations of water condensation should occur. The model reproduces a majority of the observed peaks and shows the factors influencing the process. Diurnal variation of condensation is shown to peak when the latitude and season combine to warm the atmosphere to the optimum temperature, cool enough to condense vapor at night and warm enough to cause evaporation at midday.
19. Elimination of depth degeneracy in optical frequency-domain imaging through polarization-based optical demodulation.
PubMed
Vakoc, B J; Yun, S H; Tearney, G J; Bouma, B E
2006-02-01
A novel optical frequency-domain imaging system is demonstrated that employs a passive optical demodulation circuit and a chirped digital acquisition clock derived from a voltage-controlled oscillator. The demodulation circuit allows the separation of signals from positive and negative depths to better than 50 dB, thereby eliminating depth degeneracy and doubling the imaging depth range. Our system design is compatible with dual-balanced and polarization-diverse detection, important techniques in the practical biomedical application of optical frequency-domain imaging. PMID:16480209
20. Enhanced optical clearing of skin in vivo and optical coherence tomography in-depth imaging
Wen, Xiang; Jacques, Steven L.; Tuchin, Valery V.; Zhu, Dan
2012-06-01
The strong optical scattering of skin tissue makes it very difficult for optical coherence tomography (OCT) to achieve deep imaging in skin. Significant optical clearing of in vivo rat skin sites was achieved within 15 min by topical application of an optical clearing agent PEG-400, a chemical enhancer (thiazone or propanediol), and physical massage. Only when all three components were applied together could a 15 min treatment achieve a three fold increase in the OCT reflectance from a 300 μm depth and 31% enhancement in image depth Zthreshold.
1. The Non-Linear Relationship between Silicate Absorption Depth and IR Extinction in Dense Clouds
Chiar, Jean E.; Pendleton, Y.; Ennico, K.; Boogert, A.; Greene, T.; Lada, C.; Roellig, T.; Tielens, A.; Werner, M.; Whittet, D.
2006-12-01
Interstellar silicates are likely to be a part of all grains responsible for extinction in the diffuse interstellar medium (ISM) and dense clouds. A correlation between visual extinction (Av) and the depth of the 9.7 mu silicate feature (measured as optical depth, tau(9.7)) is expected if the dust species are well mixed. In the diffuse ISM, such a correlation is observed for lines of sight in the solar neighborhood. A previous study of the silicate absorption feature in the Taurus dark cloud showed a tendency for the correlation to break down at high Av (Whittet et al. 1988, MNRAS, 233, 321), but the scatter was large. We have acquired Spitzer Infrared Spectrograph data of several lines of sight in the IC 5146, Barnard 68, Chameleon I and Serpens dense clouds. To eliminate any uncertainties associated with adopting a specific extinction law, we investigated the relationship between tau(9.7) and E(J-K). Our data set spans E(J-K) between 0.3 and 8 mag (Av=between 2-35 mag.). All lines of sight show the 9.7 mu silicate feature. For E(J-K) greater than about 2 mag, tau(9.7) levels off, much like the trend observed in the Taurus data. There are two exceptions: one line of sight in Serpens, with E(J-K) 4 mag lies on the diffuse ISM line. Another line of sight with E(J-K) 8 mag, also in Serpens, lies well below the diffuse ISM line, but well above the “flat” trend of the other dense cloud sources. This particular line of sight also has a high ice column relative to the amount of visual/infrared extinction. The cause of the “flat” trend exhibited by most of the dense cloud points is undetermined. However, in general, it is unlikely that ice mantles would have any effect on the measured silicate feature since ices are transparent in the 10 mu region.
2. Measurement of aerosol optical depth and sub-visual cloud detection using the optical depth sensor (ODS)
Toledo, D.; Rannou, P.; Pommereau, J.-P.; Sarkissian, A.; Foujols, T.
2016-02-01
A small and sophisticated optical depth sensor (ODS) has been designed to work in the atmosphere of Mars. The instrument measures alternatively the diffuse radiation from the sky and the attenuated direct radiation from the Sun on the surface. The principal goals of ODS are to retrieve the daily mean aerosol optical depth (AOD) and to detect very high and optically thin clouds, crucial parameters in understanding the Martian meteorology and climatology. The detection of clouds is undertaken at twilight, allowing the detection and characterization of clouds with opacities below 0.03 (sub-visual clouds). In addition, ODS is capable to retrieve the aerosol optical depth during nighttime from moonlight measurements. Recently, ODS has been selected at the METEO meteorological station on board the ExoMars 2018 Lander. In order to study the performance of ODS under Mars-like conditions as well as to evaluate the retrieval algorithms for terrestrial measurements, ODS was deployed in Ouagadougou (Africa) between November 2004 and October 2005, a Sahelian region characterized by its high dust aerosol load and the frequent occurrence of Saharan dust storms. The daily average AOD values retrieved by ODS were compared with those provided by a CIMEL sunphotometer of the AERONET (Aerosol Robotic NETwork) network localized at the same location. Results represent a good agreement between both ground-based instruments, with a correlation coefficient of 0.77 for the whole data set and 0.94 considering only the cloud-free days. From the whole data set, a total of 71 sub-visual cirrus (SVC) were detected at twilight with opacities as thin as 1.10-3 and with a maximum of occurrence at altitudes between 14 and 20 km. Although further optimizations and comparisons of ODS terrestrial measurements are required, results indicate the potential of these measurements to retrieve the AOD and detect sub-visual clouds.
3. Measurement of aerosol optical depth and sub-visual cloud detection using the optical depth sensor (ODS)
Toledo, D.; Rannou, P.; Pommereau, J.-P.; Sarkissian, A.; Foujols, T.
2015-09-01
A small and sophisticated optical depth sensor (ODS) has been designed to work in the atmosphere of Earth and Mars. The instrument measures alternatively the diffuse radiation from the sky and the attenuated direct radiation from the sun on the surface. The principal goals of ODS are to retrieve the daily mean aerosol optical depth (AOD) and to detect very high and optically thin clouds, crucial parameters in understanding the Martian and Earth meteorology and climatology. The detection of clouds is undertaken at twilight, allowing the detection and characterization of clouds with opacities below 0.03 (sub-visual clouds). In addition, ODS is capable to retrieve the aerosol optical depth during night-time from moonlight measurements. In order to study the performance of ODS under Mars-like conditions as well as to evaluate the retrieval algorithms for terrestrial measurements, ODS was deployed in Ouagadougou (Africa) between November 2004 and October 2005, a sahelian region characterized by its high dust aerosol load and the frequent occurrence of Saharan dust storms. The daily average AOD values retrieved by ODS were compared with those provided by a CIMEL Sun-photometer of the AERONET (Aerosol Robotic NETwork) network localized at the same location. Results represent a good agreement between both ground-based instruments, with a correlation coefficient of 0.79 for the whole data set and 0.96 considering only the cloud-free days. From the whole dataset, a total of 71 sub-visual cirrus (SVC) were detected at twilight with opacities as thin as 1.10-3 and with a maximum of occurrence at altitudes between 14 and 20 km. Although further analysis and comparisons are required, results indicate the potential of ODS measurements to detect sub-visual clouds.
4. Synthesis and nonlinear optical absorption of novel chalcone derivative compounds
Rahulan, K. Mani; Balamurugan, S.; Meena, K. S.; Yeap, G.-Y.; Kanakam, Charles C.
2014-03-01
3-(4-(dimethylamino)phenyl)-1-(4-(4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)phenyl)prop-2-en-1-one was synthesized and its third order nonlinear optical properties have been investigated using a z-scan technique with nanosecond laser pulses at 532 nm. The nonlinear absorption behavior of the compound in chloroform presents a distinct difference at different laser intensity. Interestingly, the compound showed a switchover from saturable absorption (SA) to reverse saturable absorption (RSA) with the increase of excitation intensity. Our studies suggest that compound could be used as a potential candidate for optical device applications such as optical limiters.
5. Depth resolved detection of lipid using spectroscopic optical coherence tomography
PubMed Central
Fleming, Christine P.; Eckert, Jocelyn; Halpern, Elkan F.; Gardecki, Joseph A.; Tearney, Guillermo J.
2013-01-01
Optical frequency domain imaging (OFDI) can identify key components related to plaque vulnerability but can suffer from artifacts that could prevent accurate identification of lipid rich regions. In this paper, we present a model of depth resolved spectral analysis of OFDI data for improved detection of lipid. A quadratic Discriminant analysis model was developed based on phantom compositions known chemical mixtures and applied to a tissue phantom of a lipid-rich plaque. We demonstrate that a combined spectral and attenuation model can be used to predict the presence of lipid in OFDI images. PMID:24009991
6. Strategies for Improved CALIPSO Aerosol Optical Depth Estimates
NASA Technical Reports Server (NTRS)
Vaughan, Mark A.; Kuehn, Ralph E.; Tackett, Jason L.; Rogers, Raymond R.; Liu, Zhaoyan; Omar, A.; Getzewich, Brian J.; Powell, Kathleen A.; Hu, Yongxiang; Young, Stuart A.; Avery, Melody A.; Winker, David M.; Trepte, Charles R.
2010-01-01
In the spring of 2010, the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) project will be releasing version 3 of its level 2 data products. In this paper we describe several changes to the algorithms and code that yield substantial improvements in CALIPSO's retrieval of aerosol optical depths (AOD). Among these are a retooled cloud-clearing procedure and a new approach to determining the base altitudes of aerosol layers in the planetary boundary layer (PBL). The results derived from these modifications are illustrated using case studies prepared using a late beta version of the level 2 version 3 processing code.
7. Control of enhanced optical absorption in {mu}c-Si
SciTech Connect
Kalkan, A.K.; Fonash, S.J.
1997-07-01
The influence of grain size on the enhanced optical absorption of {micro}c-Si has been investigated using films of various grain sizes prepared by solid phase crystallization. The authors show that they can control this grain size and therefore the degree of absorption changes. For grain sizes below a threshold range significant absorption enhancement can be seen in the photon energy range of 1 to {approximately}3 eV and the absorption characteristics of these films show that the dominant mode of optical transitions is indirect. A correlation between first order Raman peak broadening and enhanced absorption was found suggesting both effects are related to confinement. A simple model was developed to see how confinement in the crystallites could influence indirect optical transitions.
8. Seasonal variability of aerosol optical depth over Indian subcontinent
USGS Publications Warehouse
Prasad, A.K.; Singh, R.P.; Singh, A.; Kafatos, M.
2005-01-01
Ganga basin extends 2000 km E-W and about 400 km N-S and is bounded by Himalayas in the north. This basin is unequivocally found to be affected by high aerosols optical depth (AOD) (>0.6) throughout the year. Himalayas restricts movement of aerosols toward north and as a result dynamic nature of aerosol is seen over the Ganga basin. High AOD in this region has detrimental effects on health of more than 460 million people living in this part of India besides adversely affecting clouds formation, monsoonal rainfall pattern and Normalized Difference Vegetation Index (NDVI). Severe drought events (year 2002) in Ganga basin and unexpected failure of monsoon several times, occurred in different parts of Indian subcontinent. Significant rise in AOD (18.7%) over the central part of basin (Kanpur region) have been found to cause substantial decrease in NDVI (8.1%) since 2000. A negative relationship is observed between AOD and NDVI, magnitude of which differs from region to region. Efforts have been made to determine general distribution of AOD and its dominant departure in recent years spatially using Moderate Resolution Imaging Spectroradiometer (MODIS) data. The seasonal changes in aerosol optical depth over the Indo-Gangetic basin is found to very significant as a result of the increasing dust storm events in recent years. ?? 2005 IEEE.
9. Depth-selective X-ray absorption spectroscopy by detection of energy-loss Auger electrons
Isomura, Noritake; Soejima, Narumasa; Iwasaki, Shiro; Nomoto, Toyokazu; Murai, Takaaki; Kimoto, Yasuji
2015-11-01
A unique X-ray absorption spectroscopy (XAS) method is proposed for depth profiling of chemical states in material surfaces. Partial electron yield mode detecting energy-loss Auger electrons, called the inelastic electron yield (IEY) mode, enables a variation in the probe depth. As an example, Si K-edge XAS spectra for a well-defined multilayer sample (Si3N4/SiO2/Si) have been investigated using this method at various kinetic energies. We found that the peaks assigned to the layers from the top layer to the substrate appeared in the spectra in the order of increasing energy loss relative to the Auger electrons. Thus, the probe depth can be changed by the selection of the kinetic energy of the energy loss electrons in IEY-XAS.
10. On optical depth profiling using confocal Raman spectroscopy.
PubMed
Freebody, N A; Vaughan, A S; Macdonald, A M
2010-04-01
Until 2006 the performance of confocal Raman spectroscopy depth profiling was typically described and modeled through the application of geometrical optics, including refraction at the surface, to explain the degree of resolution and the precise form of the depth profile obtained from transparent and semicrystalline materials. Consequently a range of techniques, physical and analytical, was suggested to avoid the errors thus encountered in order to improve the practice of Raman spectroscopy, if not the understanding of the underlying mechanisms. These approaches were completely unsuccessful in accounting for the precise form of the depth profile, the fact that spectra obtained from laminated samples always contain characteristic peaks from all materials present both well above and below the focal point and that spectra can be obtained when focused some 40 mum above the sample surface. This paper provides further evidence that the physical processes underlying Raman spectroscopy are better modeled and explained through the concept of an extended illuminated volume contributing to the final Raman spectrum and modeled through a photon scattering approach rather than a point focus ray optics approach. The power of this numerical model lies in its ability to incorporate, simultaneously, the effects of degree of refraction at the surface (whether using a dry or oil objective lens), the degree of attenuation due to scatter by the bulk of the material, the Raman scattering efficiency of the material, and surface roughness effects. Through this we are now able to explain why even removing surface aberration and refraction effects through the use of oil immersion objective lenses cannot reliably ensure that the material sampled is only that at or close to the point of focus of the laser. Furthermore we show that the precise form of the depth profile is affected by the degree of flatness of the surface of the sample. Perhaps surprisingly, we show that the degree of flatness
11. Pulsed airborne lidar measurements of atmospheric optical depth using the Oxygen A-band at 765 nm.
PubMed
Riris, Haris; Rodriguez, Michael; Allan, Graham R; Hasselbrack, William; Mao, Jianping; Stephen, Mark; Abshire, James
2013-09-01
We report on an airborne demonstration of atmospheric oxygen optical depth measurements with an IPDA lidar using a fiber-based laser system and a photon counting detector. Accurate knowledge of atmospheric temperature and pressure is required for NASA's Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission, and climate modeling studies. The lidar uses a doubled erbium-doped fiber amplifier and single photon-counting detector to measure oxygen absorption at 765 nm. Our results show good agreement between the experimentally derived differential optical depth measurements with the theoretical predictions for aircraft altitudes from 3 to 13 km. PMID:24085100
12. Measurements of aerosol optical depth and diffuse-to-direct irradiance ratios in the Northeastern United States
SciTech Connect
Laulainen, N.; Larson, N.; Michalsky, J.J.
1995-12-31
13. Optical-domain subsampling for data efficient depth ranging in Fourier-domain optical coherence tomography
PubMed Central
Siddiqui, Meena; Vakoc, Benjamin J.
2012-01-01
Recent advances in optical coherence tomography (OCT) have led to higher-speed sources that support imaging over longer depth ranges. Limitations in the bandwidth of state-of-the-art acquisition electronics, however, prevent adoption of these advances into the clinical applications. Here, we introduce optical-domain subsampling as a method for imaging at high-speeds and over extended depth ranges but with a lower acquisition bandwidth than that required using conventional approaches. Optically subsampled laser sources utilize a discrete set of wavelengths to alias fringe signals along an extended depth range into a bandwidth limited frequency window. By detecting the complex fringe signals and under the assumption of a depth-constrained signal, optical-domain subsampling enables recovery of the depth-resolved scattering signal without overlapping artifacts from this bandwidth-limited window. We highlight key principles behind optical-domain subsampled imaging, and demonstrate this principle experimentally using a polygon-filter based swept-source laser that includes an intra-cavity Fabry-Perot (FP) etalon. PMID:23038343
14. Broadband optical limiting and nonlinear optical absorption properties of a novel hyperbranched conjugated polymer
Li, Chao; Liu, Chunling; Li, Quanshui; Gong, Qihuang
2004-12-01
The nonlinear transmittance of a novel hyperbranched conjugated polymer named DMA-HPV has been measured in CHCl 3 solution using a nanosecond optical parametric oscillator. DMA-HPV shows excellent optical limiting performance in the visible region from 490 to 610 nm. An explanation based on the combination of two-photon absorption and reverse saturable absorption was proposed for its huge and broadband nonlinear optical absorption.
15. Diffuse Optical Imaging and Spectroscopy of the Human Breast for Quantitative Oximetry with Depth Resolution
Yu, Yang
Near-infrared spectral imaging for breast cancer diagnostics and monitoring has been a hot research topic for the past decade. Here we present instrumentation for diffuse optical imaging of breast tissue with tandem scan of a single source-detector pair with broadband light in transmission geometry for tissue oximetry. The efforts to develop the continuous-wave (CW) domain instrument have been described, and a frequency-domain (FD) system is also used to measure the bulk tissue optical properties and the breast thickness distribution. We also describe the efforts to improve the data processing codes in the 2D spatial domain for better noise suppression, contrast enhancement, and spectral analysis. We developed a paired-wavelength approach, which is based on finding pairs of wavelength that feature the same optical contrast, to quantify the tissue oxygenation for the absorption structures detected in the 2D structural image. A total of eighteen subjects, two of whom were bearing breast cancer on their right breasts, were measured with this hybrid CW/FD instrument and processed with the improved algorithms. We obtained an average tissue oxygenation value of 87% +/- 6% from the healthy breasts, significantly higher than that measured in the diseased breasts (69% +/- 14%) (p < 0.01). For the two diseased breasts, the tumor areas bear hypoxia signatures versus the remainder of the breast, with oxygenation values of 49 +/- 11% (diseased region) vs. 61 +/- 16% (healthy regions) for the breast with invasive ductal carcinoma, and 58 +/- 8% (diseased region) vs 77 +/- 11% (healthy regions) for ductal carcinoma in situ. Our subjects came from various ethnical/racial backgrounds, and two-thirds of our subjects were less than thirty years old, indicating a potential to apply the optical mammography to a broad population. The second part of this thesis covers the topic of depth discrimination, which is lacking with our single source-detector scan system. Based on an off
16. Derivation of Aerosol Columnar Mass from MODIS Optical Depth
NASA Technical Reports Server (NTRS)
Gasso, Santiago; Hegg, Dean A.
2003-01-01
In order to verify performance, aerosol transport models (ATM) compare aerosol columnar mass (ACM) with those derived from satellite measurements. The comparison is inherently indirect since satellites derive optical depths and they use a proportionality constant to derive the ACM. Analogously, ATMs output a four dimensional ACM distribution and the optical depth is linearly derived. In both cases, the proportionality constant requires a direct intervention of the user by prescribing the aerosol composition and size distribution. This study introduces a method that minimizes the direct user intervention by making use of the new aerosol products of MODIS. A parameterization is introduced for the derivation of columnar aerosol mass (AMC) and CCN concentration (CCNC) and comparisons between sunphotometer, MODIS Airborne Simulator (MAS) and in-measurements are shown. The method still relies on the scaling between AMC and optical depth but the proportionality constant is dependent on the MODIS derived r$_{eff}$,\\eta (contribution of the accumulation mode radiance to the total radiance), ambient RH and an assumed constant aerosol composition. The CCNC is derived fkom a recent parameterization of CCNC as a function of the retrieved aerosol volume. By comparing with in-situ data (ACE-2 and TARFOX campaigns), it is shown that retrievals in dry ambient conditions (dust) are improved when using a proportionality constant dependent on r${eff}$ and \\eta derived in the same pixel. In high humidity environments, the improvement inthe new method is inconclusive because of the difficulty in accounting for the uneven vertical distribution of relative humidity. Additionally, two detailed comparisons of AMC and CCNC retrieved by the MAS algorithm and the new method are shown. The new method and MAS retrievals of AMC are within the same order of magnitude with respect to the in-situ measurements of aerosol mass. However, the proposed method is closer to the in-situ measurements than
17. In-depth quantification by using multispectral time-resolved diffuse optical tomography
Zouaoui, Judy; Hervé, Lionel; Di Sieno, Laura; Planat-Chrétien, Anne; Berger, Michel; Dalla Mora, Alberto; Pifferi, Antonio; Derouard, Jacques; Dinten, Jean-Marc
2015-07-01
Near-infrared diffuse optical tomography (DOT) is a medical imaging which gives the distribution of the optical properties of biological tissues. To obtain endogenous chromophore features in the depth of a scattering medium, a multiwavelength/time-resolved (MW/TR) DOT setup was used. Reconstructions of the three-dimensional maps of chromophore concentrations of probed media were obtained by using a data processing technique which manages Mellin-Laplace Transforms of their MW/TR optical signals and those of a known reference medium. The point was to put a constraint on the medium absorption coefficient by using a material basis composed of a given set of chromophores of known absorption spectra. Experimental measurements were conducted by injecting the light of a picosecond near- infrared laser in the medium of interest and by collecting, for several wavelengths and multiple positions, the backscattered light via two fibers (with a source-detector separation of 15 mm) connected to fast-gated single-photon avalanche diodes (SPAD) and coupled to a time-correlated single-photon counting (TCSPC) system. Validations of the method were performed in simulation in the same configuration as the experiments for different combination of chromophores. Evaluation of the technique in real conditions was investigated on liquid phantoms composed of an homogenous background and a 10 mm depth inclusion formed of combination of intralipid and inks scanned at 30 positions and at three wavelengths. Both numerical and preliminary phantom experiments confirm the potential of this method to determine chromophore concentrations in the depth of biological tissues.
18. Exploring the origin of high optical absorption in conjugated polymers.
PubMed
Vezie, Michelle S; Few, Sheridan; Meager, Iain; Pieridou, Galatia; Dörling, Bernhard; Ashraf, Raja Shahid; Goñi, Alejandro R; Bronstein, Hugo; McCulloch, Iain; Hayes, Sophia C; Campoy-Quiles, Mariano; Nelson, Jenny
2016-07-01
The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells that are limited by sub-optimal electrical transport. Here, we compare over 40 conjugated polymers, and find that many different chemical structures share an apparent maximum in their extinction coefficients. However, a diketopyrrolopyrrole-thienothiophene copolymer shows remarkably high optical absorption at relatively low photon energies. By investigating its backbone structure and conformation with measurements and quantum chemical calculations, we find that the high optical absorption can be explained by the high persistence length of the polymer. Accordingly, we demonstrate high absorption in other polymers with high theoretical persistence length. Visible light harvesting may be enhanced in other conjugated polymers through judicious design of the structure. PMID:27183327
19. Parameterization of cirrus optical depth and cloud fraction
SciTech Connect
Soden, B.
1995-09-01
This research illustrates the utility of combining satellite observations and operational analysis for the evaluation of parameterizations. A parameterization based on ice water path (IWP) captures the observed spatial patterns of tropical cirrus optical depth. The strong temperature dependence of cirrus ice water path in both the observations and the parameterization is probably responsible for the good correlation where it exists. Poorer agreement is found in Southern Hemisphere mid-latitudes where the temperature dependence breaks down. Uncertainties in effective radius limit quantitative validation of the parameterization (and its inclusion into GCMs). Also, it is found that monthly mean cloud cover can be predicted within an RMS error of 10% using ECMWF relative humidity corrected by TOVS Upper Troposphere Humidity. 1 ref., 2 figs.
20. Underwater optical wireless communications: depth-dependent beam refraction.
PubMed
Johnson, Laura J; Green, Roger J; Leeson, Mark S
2014-11-01
Global refractive gradients in seawater cause pointing problems for optical wireless communications. A refractive index depth profile of the Pacific Ocean was calculated from measured salinity, temperature, and pressure, determining the end points of a refracted and nonrefracted 200 m communication link. Numerical ray tracing was used with a point source for angles between 10° and 80° and transmission wavelengths of 500-650 nm; the maximum end-point difference found was 0.23 m. A 500 nm laser with a 0.57° full-angle FOV was traced; the nonrefracted receiver location was outside the FOV for all links angled >15° to the vertical. However, most pointing issues underwater are unlikely to be significant with suitable FOV choice and natural scattering of the source. PMID:25402887
1. Aerosol Optical Depth: A study using Thailand based Brewer Spectrophotometers
Kumharn, Wilawan; Sudhibrabha, Sumridh; Hanprasert, Kesrin
2015-12-01
The Aerosol Optical Depth (AOD) was retrieved from the direct-sun Brewer observation by the application of the Beer's law for the years 1997-2011 at two monitoring sites in Thailand (Bangkok and Songkhla). AOD values measured in Bangkok exhibited higher values than Songkhla. In addition, AOD values were higher in the morning and evening in Bangkok. In contrast, the AOD values in Songkhla were slightly lower during the mornings and late afternoons. The variation of AOD was seasonal in Bangkok, with the higher values found in summer (from Mid-February to Mid-May) compared with rainy season (Mid-May to Mid-October), whilst there was no clear seasonal pattern of AOD in Songkhla.
2. Fano resonance based optical modulator reaching 85% modulation depth
Zhao, Wenyu; Jiang, Huan; Liu, Bingyi; Jiang, Yongyuan; Tang, Chengchun; Li, Junjie
2015-10-01
In this paper, we demonstrate the combination of nematic liquid crystal with a binary silicon nanohole array to realize a high performance Fano resonance based optical modulator. The simulations using a finite difference time domain method reveal that the sharp Fano profile in the binary array originates from the interaction of the in-phased and anti-phased lattice collective resonance hybridized through lattice coupling effects. Experimental results agree very well with the simulations and demonstrate the strong dependence of the Q factor and spectral contrast of the resonance on the radius difference of the two nanohole arrays. Infiltrated with nematic liquid crystal, E7, the Fano profile can be dynamically and continuously tuned by an applied voltage, and an unprecedented modulation depth up to 85% is achieved.
3. Eight-year climatology of dust optical depth on Mars
Montabone, L.; Forget, F.; Millour, E.; Wilson, R. J.; Lewis, S. R.; Cantor, B.; Kass, D.; Kleinböhl, A.; Lemmon, M. T.; Smith, M. D.; Wolff, M. J.
2015-05-01
We have produced a multiannual climatology of airborne dust from martian year 24-31 using multiple datasets of retrieved or estimated column optical depths. The datasets are based on observations of the martian atmosphere from April 1999 to July 2013 made by different orbiting instruments: the Thermal Emission Spectrometer (TES) aboard Mars Global Surveyor, the Thermal Emission Imaging System (THEMIS) aboard Mars Odyssey, and the Mars Climate Sounder (MCS) aboard Mars Reconnaissance Orbiter (MRO). The procedure we have adopted consists of gridding the available retrievals of column dust optical depth (CDOD) from TES and THEMIS nadir observations, as well as the estimates of this quantity from MCS limb observations. Our gridding method calculates averages and uncertainties on a regularly spaced spatio-temporal grid, using an iterative procedure that is weighted in space, time, and retrieval quality. The lack of observations at certain times and locations introduces missing grid points in the maps, which therefore may result in irregularly gridded (i.e. incomplete) fields. In order to evaluate the strengths and weaknesses of the resulting gridded maps, we compare with independent observations of CDOD by PanCam cameras and Mini-TES spectrometers aboard the Mars Exploration Rovers "Spirit" and "Opportunity", by the Surface Stereo Imager aboard the Phoenix lander, and by the Compact Reconnaissance Imaging Spectrometer for Mars aboard MRO. We have statistically analyzed the irregularly gridded maps to provide an overview of the dust climatology on Mars over eight years, specifically in relation to its interseasonal and interannual variability, in addition to provide a basis for instrument intercomparison. Finally, we have produced regularly gridded maps of CDOD by spatially interpolating the irregularly gridded maps using a kriging method. These complete maps are used as dust scenarios in the Mars Climate Database (MCD) version 5, and are useful in many modeling
4. The Optical Depth Sensor (ODS) for Mars atmosphere
Toledo, D.; Rannou, P.; Pommereau, J.-P.; Sarkissian, A.; Foujols, T.
2015-10-01
A small and sophisticated optical depth sensor (ODS) has been designed to work in both Martian and Earth environments. The principal goal of ODS is to carry out the opacity due to the Martian dust as well as to characterize the high altitude clouds at twilight, crucial parameters in understanding of Martian meteorology. The instrument was initially designed for the failed MARS96 Russian mission, and also was included in the payload of several other missions [1]. Until recently, it was selected (NASA/ESA AO) in the payload of the atmospheric package DREAMS onboard the MARS 2016 mission. But following a decision of the CNES, it is no more included in the payload. In order to study the performance of ODS under a wide range of conditions as well as its capable to provide daily measurements of both dust optical thickness and high altitude clouds properties, the instrument has participated in different terrestrial campaigns. A good performance of ODS prototype (Figure 1) on cirrus clouds detection and in dust opacity estimation was previously archived in Africa during 2004-2005 and in Brasil from 2012 to nowadays. Moreover, a campaign in the arctic is expected before 2016 where fifteen ODSs will be part of an integrated observing system over the Arctic Ocean, allowing test the ODS performance in extreme conditions. In this presentation we present main principle of the retrieval, the instrumental concept, the result of the tests performed and the principal objectives of ODS in Mars.
5. [Study of retrieving formaldehyde with differential optical absorption spectroscopy].
PubMed
Li, Yu-Jin; Xie, Pin-Hua; Qin, Min; Qu, Xiao-Ying; Hu, Lin
2009-01-01
The present paper introduces the method of retrieving the concentration of HCHO with differential optical absorption spectroscopy (DOAS). The authors measured ambient HCHO in Beijing region with the help of differential optical absorption spectroscopy instrument made by ourself, and discussed numerous factors in retrieving the concentration of HCHO with differential optical absorption spectroscopy (DOAS), especially, the choice of HCHO wave band, how to avoid absorption of ambient SO2, NO2 and O3, and the influence of the Xenon lamp spectrum structure on the absorption of ambient HCHO. The authors achieved the HCHO concentration by simultaneously retrieving the concentrations of HCHO, SO2, NO2 and O3 with non-linear least square fitting method, avoiding the effect of choosing narrow wave of HCHO and the residual of SO2, NO2, O3 and the Xenon lamp spectrum structure in retrieving process to attain the concentration of HCHO, Finally the authors analyzed the origin of error in retrieving the concentration of HCHO with differential optical absorption spectroscopy (DOAS), and the total error is within 13.7% in this method. PMID:19385238
6. Absorption-edge calculations of inorganic nonlinear optical crystals
Wu, Kechen; Chen, Chuangtian
1992-03-01
A theoretical model suitable for calculating absorption edges of inorganic nonlinear optical (NLO) crystals is introduced. This model is proved to be useful to elucidate the relationship between electronic structures of NLO-active groups and macroscopic properties of absorption edges on the UV side of most of the inorganic nonlinear optical crystals. A systematic calculation of absorption edges on the UV side for several important inorganic NLO crystals is carried out by means of DV-SCM-Xα method and all calculated results are in good agreement with experimental data. These inorganic NLO crystals include LiB3O5(LBO), β-BaB2O4(BBO), KB5, KDP, Na2SbF5, Ba2TiSi2O8, iodate and NaNO2. The calculated energy level structures of LiB3O5 and β-BaB2O4 crystals are compared with the measured XPS spectra. The unusual transparent spectra of KB5 and KDP crystals are partly explained from the microstructure point of view. The effect of lone electron pair in iodate and NaNO2 crystals on their absorption edges are discussed. All these results show that Anionic Group Theory of Nonlinear Optical Crystals is useful to evaluate the absorption edges of the inorganic nonlinear optical crystal and is a powerful tool in a Molecular Engineering approach to search for new nonlinear optical materials.
7. Distributed Bragg Reflectors With Reduced Optical Absorption
DOEpatents
Klem, John F.
2005-08-16
A new class of distributed Bragg reflectors has been developed. These distributed Bragg reflectors comprise interlayers positioned between sets of high-index and low-index quarter-wave plates. The presence of these interlayers is to reduce photon absorption resulting from spatially indirect photon-assisted electronic transitions between the high-index and low-index quarter wave plates. The distributed Bragg reflectors have applications for use in vertical-cavity surface-emitting lasers for use at 1.55 .mu.m and at other wavelengths of interest.
8. Electronic structure and optic absorption of phosphorene under strain
Duan, Houjian; Yang, Mou; Wang, Ruiqiang
2016-07-01
We studied the electronic structure and optic absorption of phosphorene (monolayer of black phosphorus) under strain. Strain was found to be a powerful tool for the band structure engineering. The in-plane strain in armchair or zigzag direction changes the effective mass components along both directions, while the vertical strain only has significant effect on the effective mass in the armchair direction. The band gap is narrowed by compressive in-plane strain and tensile vertical strain. Under certain strain configurations, the gap is closed and the energy band evolves to the semi-Dirac type: the dispersion is linear in the armchair direction and is gapless quadratic in the zigzag direction. The band-edge optic absorption is completely polarized along the armchair direction, and the polarization rate is reduced when the photon energy increases. Strain not only changes the absorption edge (the smallest photon energy for electron transition), but also the absorption polarization.
9. Optical absorption spectra of palladium doped gold cluster cations
SciTech Connect
Kaydashev, Vladimir E.; Janssens, Ewald Lievens, Peter
2015-01-21
Photoabsorption spectra of gas phase Au{sub n}{sup +} and Au{sub n−1}Pd{sup +} (13 ≤ n ≤ 20) clusters were measured using mass spectrometric recording of wavelength dependent Xe messenger atom photodetachment in the 1.9–3.4 eV photon energy range. Pure cationic gold clusters consisting of 15, 17, and 20 atoms have a higher integrated optical absorption cross section than the neighboring sizes. It is shown that the total optical absorption cross section increases with size and that palladium doping strongly reduces this cross section for all investigated sizes and in particular for n = 14–17 and 20. The largest reduction of optical absorption upon Pd doping is observed for n = 15.
10. [Spectral calibration for space-borne differential optical absorption spectrometer].
PubMed
Zhou, Hai-Jin; Liu, Wen-Qing; Si, Fu-Qi; Zhao, Min-Jie; Jiang, Yu; Xue, Hui
2012-11-01
Space-borne differential optical absorption spectrometer is used for remote sensing of atmospheric trace gas global distribution. This instrument acquires high accuracy UV/Vis radiation scattered or reflected by air or earth surface, and can monitor distribution and variation of trace gases based on differential optical absorption spectrum algorithm. Spectral calibration is the premise and base of quantification of remote sensing data of the instrument, and the precision of calibration directly decides the level of development and application of the instrument. Considering the characteristic of large field, wide wavelength range, high spatial and spectral resolution of the space-borne differential optical absorption spectrometer, a spectral calibration method is presented, a calibration device was built, the equation of spectral calibration was calculated through peak searching and regression analysis, and finally the full field spectral calibration of the instrument was realized. The precision of spectral calibration was verified with Fraunhofer lines of solar light. PMID:23387142
11. Nonlinear intersubband optical absorption in a semiconductor quantum well
NASA Technical Reports Server (NTRS)
Ahn, D.; Chuang, S. L.
1987-01-01
The third-order nonlinear intersubband absorption in a semiconductor quantum well is studied theoretically using the density matrix formalism including intrasubband relaxation. It is shown that the peak absorption is reduced by half for an optical intensity 1 MW/sq cm for the well size L = 126.5 A with 3.0 x 10 to the 16th/cu cm electrons.
12. Imaging heterogeneous absorption distribution of advanced breast cancer by optical tomography
Xu, Yan; Zhu, Quing
2010-11-01
Tumor vascular patterns of advanced breast cancers are complex and heterogeneous. Two typical light absorption patterns of periphery enhancement and posterior shadowing have been observed when imaging these advanced cancers using optical tomography guided by ultrasound. We perform a series simulation and phantom experiments to systemically evaluate the effects of target parameters, target locations, and target optical properties on imaging periphery enhancement absorption distribution using reflection geometry. Large tumors are modeled as concentric semiellipsoidal targets of different outer shell and inner core optical properties. We show that larger targets of more than 3 to 4 cm diameter with outer shell thicknesses less than 1 cm can be resolved at a depth less than 3 cm. A clinical example is given to show the complex vasculature distributions seen from an advanced cancer.
13. Optical Absorption Spectra of Sodium Borate Cobalt Doped Glasses
SciTech Connect
Elokr, M. M.; Hassan, M. A.; Yaseen, A. M.; Elokr, R.
2007-02-14
Glassy system: xNa2O-(100-x-y)B2O3-yCo3O4 has been prepared by conventional melt quenching technique. Optical absorption spectra have been obtained in the range 300 - 2500 nm at room temperature. An absorption edge was observed in the near UV range, the analysis of which reveals that indirect transition is the dominant absorption mechanism. All prepared samples exhibit blue color, indicating that the Co ions are acted upon by tetrahedral ligand field. Obtained spectra were used to estimate some ligand field parameters.
14. Metal nanoparticles enhanced optical absorption in thin film solar cells
Xie, Wanlu; Liu, Fang; Qu, Di; Xu, Qi; Huang, Yidong
2011-12-01
The plasmonic enhanced absorption for thin film solar cells with silver nanoparticles (NPs) deposited on top of the amorphous silicon film (a-Si:H) solar cells and embedded inside the active layer of organic solar cells (OSCs) has been simulated and analyzed. Obvious optical absorption enhancement is obtained not only at vertical incidence but also at oblique incidence. By properly adjusting the period and size of NPs, an increased absorption enhancement of about 120% and 140% is obtained for a-Si:H solar cells and OSCs, respectively.
15. Optical absorption of several nanostructures arrays for silicon solar cells
Xu, Zhaopeng; Qiao, Huiling; Huangfu, Huichao; Li, Xiaowei; Guo, Jingwei; Wang, Haiyan
2015-12-01
To improve the efficiency and reduce the cost of solar cells, it's important to enhance the light absorption. Within the visible solar spectrum based on optimization simulations by COMSOL Multiphysics, the optical absorption of silicon cylindrical nanowires, nanocones and inverted nanocones was calculated respectively. The results reveal that the average absorption for the nanocones between 400 and 800 nm is 70.2%, which is better than cylindrical nanowires (55.3%), inverted nanocones (42.3%) and bulk silicon (42.2%). In addition, more than 95% of light from 630 to 800 nm is reflected for inverted nanocones, which can be used to enhance infrared reflection in photovoltaic devices.
16. Differential optical absorption spectrometer for measurement of tropospheric pollutants
Evangelisti, F.; Baroncelli, A.; Bonasoni, P.; Giovanelli, G.; Ravegnani, F.
1995-05-01
Our institute has recently developed a differential optical absorption spectrometry system called the gas analyzer spectrometer correlating optical absorption differences (GASCOAD), which features as a detector a linear image sensor that uses an artificial light source for long-path tropospheric-pollution monitoring. The GASCOAD, its method of eliminating interference from background sky light, and subsequent spectral analysis are reported and discussed. The spectrometer was used from 7 to 22 February 1993 in Milan, a heavily polluted metropolitan area, to measure the concentrations of SO2, NO2, O3, and HNO2 averaged over a 1.7-km horizontal light path. The findings are reported and briefly discussed.
17. Comparison of simulated and observed aerosol optical depth
Laulainen, Nels; Ghan, Steven; Easter, Richard; Zaveri, Rahul
2000-08-01
A variety of measurements have been used to evaluate the treatment of aerosol radiative properties and radiative impacts of aerosols simulated by the Model for Integrated Research on Atmospheric Global Exchanges (MIRAGE). This paper focuses on comparisons of simulated and measured aerosol optical depth (AOD). When the analyzed relative humidity is used to calculate aerosol water uptake in MIRAGE, the simulated AOD agrees with most surface measurements after cloudy conditions are filtered out and differences between model and station elevations are accounted for. Simulated AODs are low over sites in Brazil during the biomass burning season and over sites in central Canada during the wildfire season, which can be attributed to limitations in the organic and black carbon emissions data used by MIRAGE. The simulated AODs are mostly within a factor of two of satellite estimates, but MIRAGE simulates excessively high AODs off the east coast of the US and China, and too little dust off the coast of West Africa and in the Arabian Sea.
18. Aerosol optical depth trend over the Middle East
Klingmueller, Klaus; Pozzer, Andrea; Metzger, Swen; Abdelkader, Mohamed; Stenchikov, Georgiy; Lelieveld, Jos
2016-04-01
We use the combined Dark Target/Deep Blue aerosol optical depth (AOD) satellite product of the Moderate-resolution Imaging Spectroradiometer (MODIS) collection 6 to study trends over the Middle East between 2000 and 2015. Our analysis corroborates a previously identified positive AOD trend over large parts of the Middle East during the period 2001 to 2012. By relating the annual AOD to precipitation, soil moisture and surface wind, being the main factors controlling the dust cycle, we identify regions where these attributes are significantly correlated to the AOD over Saudi Arabia, Iraq and Iran. The Fertile Crescent turns out to be of prime importance for the AOD trend over these countries. Using multiple linear regression we show that AOD trend and interannual variability can be attributed to the above mentioned dust cycle parameters, confirming that the AOD increase is predominantly driven by dust. In particular, the positive AOD trend relates to a negative soil moisture trend. This suggests that increasing temperature and decreasing relative humidity in the last decade have promoted soil drying, leading to increased dust emissions and AOD; consequently an AOD increase is expected due to climate change. Based on simulations using the ECHAM/MESSy atmospheric chemistry-climate model (EMAC), we interpret the correlations identified in the observational data in terms of causal relationships.
19. Aerosol optical depth retrieval using the MERIS observation
Mei, Linlu; Rozanov, Vladimir; Vountas, Marco; Burrows, John P.
2015-04-01
Surface reflectance determination and aerosol type selection are the two main challenges for space-borne aerosol remote sensing, especially for those instruments lacking of near-infrared channels, high-temporal observations, multi-angles abilities and/or polarization information. However, space based instruments like the MEdium Resolution Imaging Spectrometer (MERIS) and the successor, Ocean and Land Colour Instrument (OLCI) with high calibration accuracy and high spatial resolution provide unique abilities for obtaining valuable aerosol information for a better understanding of the impact of aerosols on climate, which is still one of the largest uncertainties of global climate change evaluation. In this study, a new Aerosol Optical Depth (AOD) retrieval algorithm is presented. Global aerosol type and surface spectral dataset were used for the aerosol type selection and surface reflectance determination. A modified Ross-Li mode is used to describe the surface Bidirectional Reflectance Distribution Function (BRDF) effect. The comparison with operational MODIS C6 product and the validation using AErosol RObotic NETwork (AERONET) show promising results.
20. Satellite derived aerosol optical depth climatology over Bangalore, India
Sreekanth, V.
2013-06-01
Climatological aerosol optical depths (AOD) over Bangalore, India have been examined to bring out the temporal heterogeneity in columnar aerosol characteristics. AOD values at 550 nm derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard NASA's Terra and Aqua satellites, for the period of 2002-2011 have been analyzed (independently) for the purpose. Frequency distributions of the AOD values are examined to infer the monthly mean values. Monthly and seasonal variations of AOD are investigated in the light of regional synoptic meteorology. Climatological monthly and seasonal mean Terra and Aqua AOD values exhibited similar temporal variation patterns. Monthly mean AOD values increased from January, peaks during May and thereafter (except for a secondary peak during July) fall off to reach a minimum during December. Monsoon season recorded the highest climatological seasonal mean AOD, while winter season recorded the lowest. AOD values show an overall increasing trend on a yearly basis, which was found mainly due to sustained increase in the seasonal averaged AOD during summer. The results obtained in the present study are compared with that of the earlier studies over the same location and also with AOD over various other Indian locations. Finally, the radiative and climatic impacts are discussed.
1. Spatiotemporal modeling of irregularly spaced Aerosol Optical Depth data
PubMed Central
Oleson, Jacob J.; Kumar, Naresh; Smith, Brian J.
2012-01-01
Many advancements have been introduced to tackle spatial and temporal structures in data. When the spatial and/or temporal domains are relatively large, assumptions must be made to account for the sheer size of the data. The large data size, coupled with realities that come with observational data, make it difficult for all of these assumptions to be met. In particular, air quality data are very sparse across geographic space and time, due to a limited air pollution monitoring network. These “missing” values make it diffcult to incorporate most dimension reduction techniques developed for high-dimensional spatiotemporal data. This article examines aerosol optical depth (AOD), an indirect measure of radiative forcing, and air quality. The spatiotemporal distribution of AOD can be influenced by both natural (e.g., meteorological conditions) and anthropogenic factors (e.g., emission from industries and transport). After accounting for natural factors influencing AOD, we examine the spatiotemporal relationship in the remaining human influenced portion of AOD. The presented data cover a portion of India surrounding New Delhi from 2000 – 2006. The proposed method is demonstrated showing how it can handle the large spatiotemporal structure containing so much missing data for both meteorologic conditions and AOD over time and space. PMID:24470786
2. Retrieval of Aerosol Optical Depth Above Clouds from OMI Observations: Sensitivity Analysis, Case Studies
NASA Technical Reports Server (NTRS)
Torres, O.; Jethva, H.; Bhartia, P. K.
2012-01-01
A large fraction of the atmospheric aerosol load reaching the free troposphere is frequently located above low clouds. Most commonly observed aerosols above clouds are carbonaceous particles generally associated with biomass burning and boreal forest fires, and mineral aerosols originated in arid and semi-arid regions and transported across large distances, often above clouds. Because these aerosols absorb solar radiation, their role in the radiative transfer balance of the earth atmosphere system is especially important. The generally negative (cooling) top of the atmosphere direct effect of absorbing aerosols, may turn into warming when the light-absorbing particles are located above clouds. The actual effect depends on the aerosol load and the single scattering albedo, and on the geometric cloud fraction. In spite of its potential significance, the role of aerosols above clouds is not adequately accounted for in the assessment of aerosol radiative forcing effects due to the lack of measurements. In this paper we discuss the basis of a simple technique that uses near-UV observations to simultaneously derive the optical depth of both the aerosol layer and the underlying cloud for overcast conditions. The two-parameter retrieval method described here makes use of the UV aerosol index and reflectance measurements at 388 nm. A detailed sensitivity analysis indicates that the measured radiances depend mainly on the aerosol absorption exponent and aerosol-cloud separation. The technique was applied to above-cloud aerosol events over the Southern Atlantic Ocean yielding realistic results as indicated by indirect evaluation methods. An error analysis indicates that for typical overcast cloudy conditions and aerosol loads, the aerosol optical depth can be retrieved with an accuracy of approximately 54% whereas the cloud optical depth can be derived within 17% of the true value.
3. Rattlesnake Mountain Observator (46.4{degrees}N, 119.6{degrees}W) multispectral optical depth measurements, 1979--1994
SciTech Connect
Daniels, R.C.
1995-09-22
Surface measurements of solar irradiance of the atmosphere were made by a multipurpose computer-controlled scanning photometer at the Rattlesnake Mountain Observatory. The observatory is located at 46.4{degrees}N, 119.6{degrees}W at an elevation of 1088 m above mean sea level. The photometer measures the attenuation of direct solar radiation for different wavelengths using 12 filters. Five of these filters (ie., at 428 nm, 486 nm, 535 nm, 785 nm, and 1010 nm, with respective half-power widths of 2, 2, 3, 18, and 28 nm) are suitable for monitoring variations in the total optical depth of the atmosphere. Total optical depths for the five wavelength bands were derived from solar irradiance measurements taken at the observatory from August 5, 1979, to September 2, 1994; these total optical depth data are distributed with this numeric data package (NDP). To determine the contribution of atmospheric aerosols to the total optical depths, the effects of Rayleigh scattering and ozone absorption were subtracted (other molecular scattering was minimal for the five filters) to obtain total column aerosol optical depths. The total aerosol optical depths were further decomposed into tropospheric and stratospheric components by calculating a robustly smoothed mean background optical depth (tropospheric component) for each wavelength using data obtained during periods of low stratospheric aerosol loading. By subtracting the smoothed background tropospheric aerosol optical depths from the total aerosol optical depths, residual aerosol optical depths were obtained. These residuals are good estimates of the stratospheric aerosol optical depth at each wavelength and may be used to monitor the long-term effects of volcanic eruptions on the atmosphere. These data are available as an NDP from the Carbon Dioxide Information Analysis Center (CDIAC), and the NDP consists of this document and a set of computerized data files.
4. Spectroradiometer with wedge interference filters (SWIF): measurements of the spectral optical depths at Mauna Loa Observatory.
PubMed
Vasilyev, O B; Leyva, A; Muhila, A; Valdes, M; Peralta, R; Kovalenko, A P; Welch, R M; Berendes, T A; Isakov, V Y; Kulikovskiy, Y P; Sokolov, S S; Strepanov, N N; Gulidov, S S; von Hoyningen-Huene, W
1995-07-20
A spectroradiometer with wedge interference filters (SWIF) (the filters were produced by Carl Zeiss, Jena, Germany) and a CCD matrix (which was of Russian production) that functions as the sensor has been designed and built for use in ground-based optical sensing of the atmosphere and the Earth's surface in the spectral range of 0.35-1.15 µm. Absolute calibration of this instrument was performed through a series of observations of direct solar radiation at Mauna Loa Observatory (MLO) in Hawaii in May and June 1993. Spectral optical depth (SOD) measurements that were made during these field experiments provided detailed spectral information about both aerosol extinction (scattering plus absorption) and molecular absorption in the atmosphere above the site at MLO. The aerosol-SOD measurements were compared with narrow-band radiometer measurements at wavelengths of 380, 500, and 778 nm The SWIF and narrow-band radiometer measurements are in agreement to within the experimental error. At a wavelength of 500 nm, the aerosol SOD was found to be approximately 0.045. Adescription of the SWIF instrument, its absolute calibration, and the determination of atmospheric SOD's at MLO are presented. PMID:21052277
5. Improved retrieval of aerosol optical depth by satellite
Drury, Easan Evans
Atmospheric aerosols are of major concern for public health and climate change, but their sources and atmospheric distributions remain poorly constrained. Satellite-borne radiometers offer a new constraint on aerosol sources and processes by providing global aerosol optical depth (AOD) retrievals. However, quantitative evaluation of chemical transport models (CTMs) with AOD products retrieved from satellite backscattered reflectances can be compromised by inconsistent assumptions of aerosol optical properties and errors in surface reflectance estimates. We present an improved AOD retrieval algorithm for the MODIS satellite instrument using locally derived surface reflectances and CTM aerosol optical properties. Assuming negligible atmospheric reflectance at 2.13 in cloud-free conditions, we derive 0.47/2.13 and 0.65/2.13 surface reflectance ratios at 1°x1.25° horizontal resolution for the continental United States in summer 2004 from the subset of top-of-atmosphere (TOA) reflectance data with minimal aerosol reflectance. We find higher ratios over arid regions than those assumed in the operational MODIS AOD retrieval algorithm, explaining the high AOD bias found in these regions. We simulate TOA reflectances for each MODIS scene using local aerosol optical properties from the GEOS-Chem CTM, and fit these reflectances to the observed MODIS TOA reflectances for a best estimate of AODs for each scene. Comparison with coincident ground-based (AERONET) AOD observations in the western and central United States during the summer of 2004 shows considerable improvement over the operational MODIS AOD products in this region. We find the AOD retrieval is more accurate at 0.47 than at 0.65 mum because of the higher signal to noise ratio, and that the correlation between MODIS and AERONET AODs improves as averaging time increases. We further improve the AOD retrieval method using an extensive ensemble of aircraft, ground-based, and satellite aerosol observations during the
6. An Atmospheric Radiation Measurement Value-Added Product to Retrieve Optically Thin Cloud Visible Optical Depth using Micropulse Lidar
SciTech Connect
Lo, C; Comstock, JM; Flynn, C
2006-10-01
The purpose of the Micropulse Lidar (MPL) Cloud Optical Depth (MPLCOD) Value-Added Product (VAP) is to retrieve the visible (short-wave) cloud optical depth for optically thin clouds using MPL. The advantage of using the MPL to derive optical depth is that lidar is able to detect optically thin cloud layers that may not be detected by millimeter cloud radar or radiometric techniques. The disadvantage of using lidar to derive optical depth is that the lidar signal becomes attenuation limited when τ approaches 3 (this value can vary depending on instrument specifications). As a result, the lidar will not detect optically thin clouds if an optically thick cloud obstructs the lidar beam.
7. AIR MONITORING BY DIFFERENTIAL OPTICAL ABSORPTION SPECTROMETRY IN BAYTOWN, TEXAS
EPA Science Inventory
This report documents the results of a field study carried out in Baytown, Texas in August 1993. ne goal of the field study was to evaluate calibration and audit procedures for a differential optical absorption spectrometry (DOAS) system. he other major goal of the study was to c...
8. Focused optical and acoustic beams in media with nonlinear absorption
Rudenko, O. V.; Sukhorukov, A. A.
1996-11-01
Optical and acoustic beams are known to be useful for medical and biological applications, such as diagnostics, surgery, etc. At high intensities both nonlinear lens effects and nonlinear absorption can be significant for the beams. The nonlinear absorption arises due to two-photon optical processes or acoustic shock wave formation. The present work is devoted to the theoretical description of nonlinear beam propagation and focal spot formation taking into account the competition between focusing, diffraction and absorption. We derived a new nonlinear integro- differential equation describing the spatial evolution of the beam width. The general analytical solution of this equation is obtained for arbitrary boundary conditions. The simple formulas are derived for the angle divergence in the far field, as well as for beam width at nonlinear waist. The results of the analysis of these key parameters in different situations are presented.
9. Tunable enhanced optical absorption of graphene using plasmonic perfect absorbers
SciTech Connect
Cai, Yijun; Zhu, Jinfeng; Liu, Qing Huo
2015-01-26
Enhancement and manipulation of light absorption in graphene is a significant issue for applications of graphene-based optoelectronic devices. In order to achieve this purpose in the visible region, we demonstrate a design of a graphene optical absorber inspired by metal-dielectric-metal metamaterial for perfect absorption of electromagnetic waves. The optical absorbance ratios of single and three atomic layer graphene are enhanced up to 37.5% and 64.8%, respectively. The graphene absorber shows polarization-dependence and tolerates a wide range of incident angles. Furthermore, the peak position and bandwidth of graphene absorption spectra are tunable in a wide wavelength range through a specific structural configuration. These results imply that graphene in combination with plasmonic perfect absorbers have a promising potential for developing advanced nanophotonic devices.
10. Aerosol optical depth trend over the Middle East
Klingmüller, Klaus; Pozzer, Andrea; Metzger, Swen; Stenchikov, Georgiy L.; Lelieveld, Jos
2016-04-01
We use the combined Dark Target/Deep Blue aerosol optical depth (AOD) satellite product of the moderate-resolution imaging spectroradiometer (MODIS) collection 6 to study trends over the Middle East between 2000 and 2015. Our analysis corroborates a previously identified positive AOD trend over large parts of the Middle East during the period 2001 to 2012. We relate the annual AOD to precipitation, soil moisture and surface winds to identify regions where these attributes are directly related to the AOD over Saudi Arabia, Iraq and Iran. Regarding precipitation and soil moisture, a relatively small area in and surrounding Iraq turns out to be of prime importance for the AOD over these countries. Regarding surface wind speed, the African Red Sea coastal area is relevant for the Saudi Arabian AOD. Using multiple linear regression we show that AOD trends and interannual variability can be attributed to soil moisture, precipitation and surface winds, being the main factors controlling the dust cycle. Our results confirm the dust driven AOD trends and variability, supported by a decreasing MODIS-derived Ångström exponent and a decreasing AERONET-derived fine mode fraction that accompany the AOD increase over Saudi Arabia. The positive AOD trend relates to a negative soil moisture trend. As a lower soil moisture translates into enhanced dust emissions, it is not needed to assume growing anthropogenic aerosol and aerosol precursor emissions to explain the observations. Instead, our results suggest that increasing temperature and decreasing relative humidity in the last decade have promoted soil drying, leading to increased dust emissions and AOD; consequently an AOD increase is expected due to climate change.
11. Deriving atmospheric visibility from satellite retrieved aerosol optical depth
Riffler, M.; Schneider, Ch.; Popp, Ch.; Wunderle, S.
2009-04-01
Atmospheric visibility is a measure that reflects different physical and chemical properties of the atmosphere. In general, poor visibility conditions come along with risks for transportation (e.g. road traffic, aviation) and can negatively impact human health since visibility impairment often implies the presence of atmospheric pollution. Ambient pollutants, particulate matter, and few gaseous species decrease the perceptibility of distant objects. Common estimations of this parameter are usually based on human observations or devices that measure the transmittance of light from an artificial light source over a short distance. Such measurements are mainly performed at airports and some meteorological stations. A major disadvantage of these observations is the gap between the measurements, leaving large areas without any information. As aerosols are one of the most important factors influencing atmospheric visibility in the visible range, the knowledge of their spatial distribution can be used to infer visibility with the so called Koschmieder equation, which relates visibility and atmospheric extinction. In this study, we evaluate the applicability of satellite aerosol optical depth (AOD) products from the Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) to infer atmospheric visibility on large spatial scale. First results applying AOD values scaled with the planetary boundary layer height are promising. For the comparison we use a full automated and objective procedure for the estimation of atmospheric visibility with the help of a digital panorama camera serving as ground truth. To further investigate the relation between the vertical measure of AOD and the horizontal visibility data from the Aerosol Robotic Network (AERONET) site Laegeren (Switzerland), where the digital camera is mounted, are included as well. Finally, the derived visibility maps are compared with synoptical observations in central
12. Aerosol optical depth increase in partly cloudy conditions
SciTech Connect
Chand, Duli; Wood, R.; Ghan, Steven J.; Wang, Minghuai; Ovchinnikov, Mikhail; Rasch, Philip J.; Miller, Steven D.; Schichtel, Bret; Moore, Tom
2012-09-14
Remote sensing observations of aerosol from surface and satellite instruments are extensively used for atmospheric and climate research. From passive sensors, the apparent cloud-free atmosphere in the vicinity of clouds often appears to be brighter then further away from the clouds, leading to an enhancement in the retrieved aerosol optical depth. Mechanisms contributing to this enhancement, including contamination by undetected clouds, hygroscopic growth of aerosol particles, and meteorological conditions, have been debated in recent literature, but an extent to which each of these factors influence the observed enhancement is poorly known. Here we used 11 years of daily global observations at 10x10 km2 resolution from the MODIS on the NASA Terra satellite to quantify as a function of cloud fraction (CF). Our analysis reveals that, averaged over the globe, the clear sky is enhanced by ? = 0.05 which corresponds to relative enhancements of 25% in cloudy conditions (CF=0.8-0.9) compared with relatively clear conditions (CF=0.1-0.2). Unlike the absolute enhancement ?, the relative increase in ? is rather consistent in all seasons and is 25-35% in the subtropics and 15-25% at mid and higher latitudes. Using a simple Gaussian probability density function model to connect cloud cover and the distribution of relative humidity, we argue that much of the enhancement is consistent with aerosol hygroscopic growth in the humid environment surrounding clouds. Consideration of these cloud-dependent effects will facilitate understanding aerosol-cloud interactions and reduce the uncertainty in estimates of aerosol radiative forcing by global climate models.
13. Large Magellanic Cloud Microlensing Optical Depth with Imperfect Event Selection
Bennett, David P.
2005-11-01
I present a new analysis of the MACHO Project 5.7 yr Large Magellanic Cloud (LMC) microlensing data set that incorporates the effects of contamination of the microlensing event sample by variable stars. Photometric monitoring of MACHO LMC microlensing event candidates by the EROS and OGLE groups has revealed that one of these events is likely to be a variable star, while additional data have confirmed that many of the other events are very likely to be microlensing. These additional data on the nature of the MACHO microlensing candidates are incorporated into a simple likelihood analysis to derive a probability distribution for the number of MACHO microlens candidates that are true microlensing events. This analysis shows that 10-12 of the 13 events that passed the MACHO selection criteria are likely to be microlensing events, with the other 1-3 being variable stars. This likelihood analysis is also used to show that the main conclusions of the MACHO LMC analysis are unchanged by the variable star contamination. The microlensing optical depth toward the LMC is τ=(1.0+/-0.3)×10-7. If this is due to microlensing by known stellar populations plus an additional population of lens objects in the Galactic halo, then the new halo population would account for 16% of the mass of a standard Galactic halo. The MACHO detection exceeds the expected background of two events expected from ordinary stars in standard models of the Milky Way and LMC at the 99.98% confidence level. The background prediction is increased to three events if maximal disk models are assumed for both the Milky Way and LMC, but this model fails to account for the full signal seen by MACHO at the 99.8% confidence level.
14. Intercomparison of Desert Dust Optical Depth from Satellite Measurements
NASA Technical Reports Server (NTRS)
Carboni, E.; Thomas, G. E.; Sayer, A. M.; Siddans, R.; Poulsen, C. A.; Grainger, R. G.; Ahn, C.; Antoine, D.; Bevan, S.; Braak, R.; Brindley, H.; DeSouza-Machado, S.; Deuze, J. L.; Diner, D.; Ducos, F.; Grey, W.; Hsu, C.; Kalashnikova, O. V.; Kahn, R.; North, P. R. J.; Salustro, C.; Smith, A.; Tanre, D.; Torres, O.; Veihelmann, B,
2012-01-01
This work provides a comparison of satellite retrievals of Saharan desert dust aerosol optical depth (AOD) during a strong dust event through March 2006. In this event, a large dust plume was transported over desert, vegetated, and ocean surfaces. The aim is to identify the differences between current datasets. The satellite instruments considered are AATSR, AIRS, MERIS, MISR, MODIS, OMI, POLDER, and SEVIRI. An interesting aspect is that the different algorithms make use of different instrument characteristics to obtain retrievals over bright surfaces. These include multi-angle approaches (MISR, AATSR), polarisation measurements (POLDER), single-view approaches using solar wavelengths (OMI, MODIS), and the thermal infrared spectral region (SEVIRI, AIRS). Differences between instruments, together with the comparison of different retrieval algorithms applied to measurements from the same instrument, provide a unique insight into the performance and characteristics of the various techniques employed. As well as the intercomparison between different satellite products, the AODs have also been compared to co-located AERONET data. Despite the fact that the agreement between satellite and AERONET AODs is reasonably good for all of the datasets, there are significant differences between them when compared to each other, especially over land. These differences are partially due to differences in the algorithms, such as assumptions about aerosol model and surface properties. However, in this comparison of spatially and temporally averaged data, it is important to note that differences in sampling, related to the actual footprint of each instrument on the heterogeneous aerosol field, cloud identification and the quality control flags of each dataset can be an important issue.
15. Programmable diffractive optical elements for extending the depth of focus in ophthalmic optics
Romero, Lenny A.; Millán, María. S.; Jaroszewicz, Zbigniew; Kołodziejczyk, Andrzej
2015-01-01
The depth of focus (DOF) defines the axial range of high lateral resolution in the image space for object position. Optical devices with a traditional lens system typically have a limited DOF. However, there are applications such as in ophthalmology, which require a large DOF in comparison to a traditional optical system, this is commonly known as extended DOF (EDOF). In this paper we explore Programmable Diffractive Optical Elements (PDOEs), with EDOF, as an alternative solution to visual impairments, especially presbyopia. These DOEs were written onto a reflective liquid cystal on silicon (LCoS) spatial light modulator (SLM). Several designs of the elements are analyzed: the Forward Logarithmic Axicon (FLAX), the Axilens (AXL), the Light sword Optical Element (LSOE), the Peacock Eye Optical Element (PE) and Double Peacock Eye Optical Element (DPE). These elements focus an incident plane wave into a segment of the optical axis. The performances of the PDOEs are compared with those of multifocal lenses. In all cases, we obtained the point spread function and the image of an extended object. The results are presented and discussed.
16. Optical absorption of thin film on a Lambertian reflector substrate
Sheng, P.
1984-05-01
A formula is derived for calculating the optical absorption of thin films deposited on a Lambertian reflector substrate. It is shown that compared with the case of flat reflecting substrate, the incoherent absorption is enhanced by a factor of m x epsilon (1) in the weak absorption limit, where epsilon (1) is the real part of the film dielectric constant and m near two is a slightly varying function of epsilon (1). For a 0.5-micron a-SiH(x) (bandgap 1.7 eV) solar cell with a Lambertian reflector substrate, the total absorption in terms of the short-circuit current is calculated to be 18.63 mA/sq cm.
17. Marcasite revisited: Optical absorption gap at room temperature
Sánchez, C.; Flores, E.; Barawi, M.; Clamagirand, J. M.; Ares, J. R.; Ferrer, I. J.
2016-03-01
Jagadeesh and Seehra published in 1980 that the marcasite band gap energy is 0.34 eV. However, recent calculations and experimental approximations accomplished by several research groups point out that the marcasite band gap energy should be quite similar to that of pyrite (of the order of 0.8-1.0 eV). By using diffuse reflectance spectroscopy (DRS) we have determined that marcasite has no optical absorption gap at photon energies 0.06 ≤ hν ≤ 0.75 eV and that it has two well defined optical transitions at ~ 0.9 eV and ~ 2.2 eV quite similar to those of pyrite. Marcasite optical absorption gap appears to be Eg ≅ 0.83 ± 0.02 eV and it is due to an allowed indirect transition.
18. Design of Optical Systems with Extended Depth of Field: An Educational Approach to Wavefront Coding Techniques
ERIC Educational Resources Information Center
Ferran, C.; Bosch, S.; Carnicer, A.
2012-01-01
A practical activity designed to introduce wavefront coding techniques as a method to extend the depth of field in optical systems is presented. The activity is suitable for advanced undergraduate students since it combines different topics in optical engineering such as optical system design, aberration theory, Fourier optics, and digital image…
19. Study on optical weak absorption of borate crystals
Li, Xiaomao; Hu, Zhanggui; Yue, Yinchao; Yu, Xuesong; Lin, Zheshuai; Zhang, Guochun
2013-10-01
Borate crystal is an important type of nonlinear optical crystals used in frequency conversion in all-solid-state lasers. Especially, LiB3O5 (LBO), CsB3O5 (CBO) and CsLiB6O10 (CLBO) are the most advanced. Although these borate crystals are all constructed by the same anionic group-(B3O7)5-, they show different nonlinear optical properties. In this study, bulk weak absorption values of three borate crystals have been studied at 1064 nm by a photothermal common-path interferometer. The bulk weak absorption values of them along [1 0 0], [0 1 0] and [0 0 1] directions were obtained, respectively, to be approximately 17.5 ppm cm-1, 15 ppm cm-1 and 20 ppm cm-1 (LBO); 80 ppm cm-1, 100 ppm cm-1 and 40 ppm cm-1 (CBO); 600 ppm cm-1, 600 ppm cm-1 and 150 ppm cm-1 (CLBO) at 1064 nm. The results showed an obvious discrepancy of the values of these crystals along three axis directions. A correlation between the bulk weak absorption property and crystal intrinsic structure was then discussed. It is found that the bulk weak absorption values strongly depend on the interstitial area surrounded by the B-O frames. The interstitial area is larger, the bulk weak absorption value is higher.
20. Simultaneous measurement of thermal diffusivity and optical absorption coefficient using photothermal radiometry. II Multilayered solids
Salazar, Agustín; Fuente, Raquel; Apiñaniz, Estibaliz; Mendioroz, Arantza; Celorrio, R.
2011-08-01
The aim of this work is to analyze the ability of modulated photothermal radiometry to retrieve the thermal diffusivity and the optical absorption coefficient of layered materials simultaneously. First, we extend the thermal quadrupole method to calculate the surface temperature of semitransparent multilayered materials. Then, this matrix method is used to evaluate the influence of heat losses by convection and radiation, the influence of the use of thin paint layers on the accuracy of thermal diffusivity measurements, and the effect of lateral heat diffusion due to the use of Gaussian laser beams. Finally, we apply the quadrupole method to retrieve (a) the thermal contact resistance in glass stacks and (b) the thermal diffusivity and optical absorption coefficient depth profiles in heterogeneous materials with continuously varying physical properties, as is the case of functionally graded materials and partially cured dental resins.
1. Aerosol Optical Depth Trends in Switzerland from 1995 - 2010
Nyeki, S.; Halios, C.; Eleftheriadis, K.; Wehrli, C.; Groebner, J.
2011-12-01
Accurate and long-term measurements of aerosol optical depth (AOD) serve as an important contribution to studies assessing the effect of aerosols on climate change. In this study re-calibrated and updated AOD climatologies are reported for two sites in Switzerland for 1995 - 2010, (Davos, 1580 m and Jungfraujoch, 3580 m), as well as a new data-set for an urban site Bern (560 m asl). At Davos and Jungfraujoch AOD observations were conducted using an SPM2000 sun-photometer system until 2003 and with precision filter radiometers (PFR) from 1999 onwards, while continuous AOD measurements were conducted at Bern over the 1998 - 2006 period with SPM2000. In order to homogenize these diverse data-sets, procedures and algorithms of the GAW-PFR (Global Atmosphere Watch - Precision Filter Radiometer, WMO) program to derive AOD are used here. GAW-PFR procedures and algorithms use: 1) in-situ air pressure data, ii) in-situ or satellite ozone data, 3) commonly-used algorithms for cloud-screening, airmass calculation etc. The AOD average for the available 1-month data-set was 0.026 (± 0.013; ± 1 stdev) at Jungfraujoch, 0.069 (± 0.037) at Davos and 0.174 (± 0.054) at Bern illustrating the typical increase in average AOD with decreasing altitude due to surface aerosol sources, and to boundary layer/free troposphere dynamics. A trend analysis was performed using the seasonal Kendall test, and Sen's slope estimator on logarithmized AOD data. The seasonal Kendall test is an extension of the Mann-Kendall test, a non-parametric technique which determines if a monotonic increasing or de-creasing long-term trend exists. As AOD data are log-normally distributed, the logarithm of AOD was used for analysis. Statistically significant linear trends was found only at Jungfraujoch while for Davos and Bern even though no statistically significant trends were observed, significant trends during certain months were detected (e.g. during May, July, and December for Bern). Factors which could
2. VIIRS Aerosol Optical Depth (AOD) Products for Air Quality Applications
Huff, A. K.; Zhang, H.; Kondragunta, S.; Laszlo, I.
2014-12-01
The air quality community uses satellite aerosol optical depth (AOD) for a variety of applications, including daily air quality forecasting, retrospective event analysis, and justification for Exceptional Events. AOD is suitable for ambient air quality applications because is related to particulate matter (e.g., PM2.5) concentrations in the atmosphere; higher values of AOD correspond to higher concentrations of particulate matter. AOD is useful for identifying and tracking areas of high PM2.5 concentrations that correspond to air quality events, such as wildfires, dust storms, or haze episodes. Currently, the air quality community utilizes AOD from the MODIS instrument on NASA's polar-orbiting Terra and Aqua satellites and from NOAA's GOES geostationary satellites (e.g, GASP). The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on the Suomi-NPP satellite is making AOD measurements that are similar to MODIS AOD, but with higher spatial resolution. Two AOD products are available from VIIRS: the 750 m nadir resolution Intermediate Product (IP) and the 6 km resolution Environmental Data Record (EDR) product, which is aggregated from IP measurements. These VIIRS AOD products offer a substantial increase in spatial resolution compared to the MODIS AOD 3 km and 10 km AOD products, respectively. True color (RGB) imagery is also available from VIIRS as a decision aid for air quality applications. It serves as a complement to AOD measurements by providing visible information about areas of smoke, haze, and blowing dust in the atmosphere. Case studies of VIIRS AOD and RGB data for recent air quality events will be presented, with a focus on wildfires, and the relative pros and cons of the VIIRS AOD IP and EDR for air quality applications will be discussed in comparison to MODIS AOD products. Improvements to VIIRS aerosol products based on user feedback as part of the NOAA Satellite Air Quality Proving Ground (AQPG) will be outlined, and an overview of future
3. Two-Photon-Absorption Scheme for Optical Beam Tracking
NASA Technical Reports Server (NTRS)
Ortiz, Gerardo G.; Farr, William H.
2011-01-01
A new optical beam tracking approach for free-space optical communication links using two-photon absorption (TPA) in a high-bandgap detector material was demonstrated. This tracking scheme is part of the canonical architecture described in the preceding article. TPA is used to track a long-wavelength transmit laser while direct absorption on the same sensor simultaneously tracks a shorter-wavelength beacon. The TPA responsivity was measured for silicon using a PIN photodiode at a laser beacon wavelength of 1,550 nm. As expected, the responsivity shows a linear dependence with incident power level. The responsivity slope is 4.5 x 10(exp -7) A/W2. Also, optical beam spots from the 1,550-nm laser beacon were characterized on commercial charge coupled device (CCD) and complementary metal-oxide semiconductor (CMOS) imagers with as little as 13.7 microWatts of optical power (see figure). This new tracker technology offers an innovative solution to reduce system complexity, improve transmit/receive isolation, improve optical efficiency, improve signal-to-noise ratio (SNR), and reduce cost for free-space optical communications transceivers.
4. Optical absorption analysis and optimization of gold nanoshells.
PubMed
Tuersun, Paerhatijiang; Han, Xiang'e
2013-02-20
Gold nanoshells, consisting of a nanoscale dielectric core coated with an ultrathin gold shell, have wide biomedical applications due to their strong optical absorption properties. Gold nanoshells with high absorption efficiencies can help to improve these applications. We investigate the effects of the core material, surrounding medium, core radius, and shell thickness on the absorption spectra of gold nanoshells by using the light-scattering theory of a coated sphere. Our results show that the position and intensity of the absorption peak can be tuned over a wide range by manipulating the above-mentioned parameters. We also obtain the optimal absorption efficiencies and structures of hollow gold nanoshells and gold-coated SiO(2) nanoshells embedded in water at wavelengths of 800, 820, and 1064 nm. The results show that hollow gold nanoshells possess the maximum absorption efficiency (5.42) at a wavelength of 800 nm; the corresponding shell thickness and core radius are 4.8 and 38.9 nm, respectively. They can be used as the ideal photothermal conversation particles for biomedical applications. PMID:23435006
5. Absorption characteristics of optically complex inland waters: Implications for water optical classification
Shi, Kun; Li, Yunmei; Li, Lin; Lu, Heng
2013-06-01
Multiple bio-optical measurements were conducted in inland waters of China, including Lake Taihu [spring and autumn], Lake Chaohu, Lake Dianchi, and Three Gorges Reservoirs. The variations in the absorption characteristics of chromophoric dissolved organic matter (CDOM), phytoplankton, and non-algal particles (NAP) and their relative contributions to total absorption among these waters were analyzed. The obtained results indicated that these areas are representative of the optically complex inland waters characterized by strong regional variations of their absorption properties. By means of the relative contributions of NAP and phytoplankton to the total water absorption at 550 and 675 nm, these waters were classified into three optical water types, each one having specific biogeochemical and optical properties. Two of the types were distinct and corresponded to waters that are optically controlled by NAP (Type I) and dominated by phytoplankton (Type III). Type II was related to relatively optically mixed waters where the absorption properties are controlled by NAP and phytoplankton. Additionally, the differences in remote-sensing reflectance (Rrs) spectra among the three classified water types were clarified to establish optical criteria for identifying these water types. On this basis, the classification criteria for MERIS images were developed, which allowed one to cluster every Rrs spectrum into one of the three water types by comparing the values from band 6, band 8, and band 9 of MERIS images. The proposed criteria were subsequently conducted to map the water types of Lake Taihu using MERIS images.
6. Hi Gas Cycles and Lyman Continuum Optical Depth in Low-Redshift Starbursts
Neutral gas both fuels star formation and determines the propagation of ionizing photons. In this work, we reveal the interactions between H I, star formation, and radiative feedback in two samples of low-redshift starbursts. Using the ALFALFA-Halpha sample, we present the first comparison of starbursts and non-starbursts within a statistically uniform, H I-selected sample. The moderate H I gas fractions of the starbursts relative to non-starbursts indicate efficient HI to H2 conversion and show that the H I supply is largely unaffected by ionizing radiation. Mergers may trigger the more massive starbursts, while the absence of obvious kinematical disturbances in dwarf starbursts may indicate periodic starburst activity, triggered by cycles of gas expulsion and re-accretion. While the ALFALFA-Halpha galaxies demonstrate that starbursts may maintain large H I reservoirs, the more powerful starbursts in the Green Pea (GP) galaxies illustrate the effects of extreme radiative feedback on neutral gas. To investigate whether the enormous [O III]/[O II] ratios in the most extreme GPs indicate LyC escape, we use photoionization modeling to constrain their ionizing sources and optical depths. Radiation from Wolf-Rayet stars or unusually hot O stars reproduces the observed [O III]/[O II] ratios, but no clear signatures of these stars are present. The GP spectra do suggest the presence of shocks, however, and accounting for shock emission necessitates a low optical depth. We therefore suggest that the GPs may be a new class of low-redshift LyC Emitters (LCEs), and we evaluate this scenario using Hubble Space Telescope COS spectra of four GPs. With these spectra, we develop a simple physical picture of the neutral gas optical depth and geometry that explains the previously enigmatic link between Lyalpha, Si II, and Si II* lines observed in high-redshift Lyalpha Emitters. Two GPs are likely optically thin along the line of sight, and their strong, narrow Lyalpha emission, weak
7. Anomalous nonlinear absorption in epsilon-near-zero materials: optical limiting and all-optical control.
PubMed
Vincenti, M A; de Ceglia, D; Scalora, Michael
2016-08-01
We investigate nonlinear absorption in films of epsilon-near-zero materials. The combination of large local electric fields at the fundamental frequency and material losses at the harmonic frequencies induce unusual intensity-dependent phenomena. We predict that the second-order nonlinearity of a low-damping, epsilon-near-zero slab produces an optical limiting effect that mimics a two-photon absorption process. Anomalous absorption profiles that depend on low permittivity values at the pump frequency are also predicted for third-order nonlinearities. These findings suggest new opportunities for all-optical light control and novel ways to design reconfigurable and tunable nonlinear devices. PMID:27472631
8. Contribution of a visual pigment absorption spectrum to a visual function: depth perception in a jumping spider
PubMed Central
Nagata, Takashi; Arikawa, Kentaro; Terakita, Akihisa
2013-01-01
Absorption spectra of visual pigments are adaptively tuned to optimize informational capacity in most visual systems. Our recent investigation of the eyes of the jumping spider reveals an apparent exception: the absorption characteristics of a visual pigment cause defocusing of the image, reducing visual acuity generally in a part of the retina. However, the amount of defocus can theoretically provide a quantitative indication of the distance of an object. Therefore, we proposed a novel mechanism for depth perception in jumping spiders based on image defocus. Behavioral experiments revealed that the depth perception of the spider depended on the wavelength of the ambient light, which affects the amount of defocus because of chromatic aberration of the lens. This wavelength effect on depth perception was in close agreement with theoretical predictions based on our hypothesis. These data strongly support the hypothesis that the depth perception mechanism of jumping spiders is based on image defocus.
9. Simultaneous multiple-depths en-face optical coherence tomography using multiple signal excitation of acousto-optic deflectors.
PubMed
Zurauskas, Mantas; Rogers, John; Podoleanu, Adrian Gh
2013-01-28
We present a novel low-coherence interferometer configuration, equipped with acousto-optic deflectors that can be used to simultaneously acquire up to eight time domain optical coherence tomography en-face images. The capabilities of the configuration are evaluated in terms of depth resolution, signal to noise ratio and crosstalk. Then the configuration is employed to demonstrate simultaneous en-face optical coherence tomography imaging at five different depths in a specimen of armadillidium vulgare. PMID:23389175
10. Birefringence and anisotropic optical absorption in porous silicon
SciTech Connect
Efimova, A. I. Krutkova, E. Yu.; Golovan', L. A.; Fomenko, M. A.; Kashkarov, P. K.; Timoshenko, V. Yu.
2007-10-15
The refractive indices and the coefficients of optical absorption by free charge carriers and local vibrations in porous silicon (por-Si) films, comprising nanometer-sized silicon residues (nanocrystals) separated by nanometer-sized pores (nanopores) formed in the course of electrochemical etching of the initial single crystal silicon, have been studied by polarization-resolved IR absorption spectroscopy techniques. It is shown that the birefringence observed in por-Si is related to the anisotropic shapes of nanocrystals and nanopores, while the anisotropy (dichroism) of absorption by the local vibrational modes is determined predominantly by the microrelief of the surface of nanocrystals. It is demonstrated that silicon-hydrogen surface bonds in nanocrystals can be restored by means of selective hydrogen thermodesorption with the formation of a considerable number of H-terminated surface Si-Si dimers.
11. Neuron absorption study and mid-IR optical excitations
Guo, Dingkai; Chen, Xing; Vadala, Shilpa; Leach, Jennie; Kostov, Yordan; Bewley, William W.; Kim, Chul-Soo; Kim, Mijin; Canedy, Chadwick L.; Merritt, Charles D.; Vurgaftman, Igor; Meyer, Jerry R.; Choa, Fow-Sen
2012-02-01
Neuronal optical excitation can provide non-contacting tools to explore brain circuitry and a durable stimulation interface for cardiac pacing and visual as well as auditory sensory neuronal stimulation. To obtain accurate absorption spectra, we scan the transmission of neurons in cell culture medium, and normalize it by subtracting out the absorption spectrum of the medium alone. The resulting spectra show that the main neuronal absorption peaks are in the 3000- 6000nm band, although there is a smaller peak near 1450nm. By coupling the output of a 3μm interband cascade laser (ICL) into a mid-IR fluorozirconate fiber, we can effectively deliver more than 1J/cm2 photon intensity to the excitation site for neuronal stimulation.
12. Optical absorption of ion-beam sputtered amorphous silicon coatings
Steinlechner, Jessica; Martin, Iain W.; Bassiri, Riccardo; Bell, Angus; Fejer, Martin M.; Hough, Jim; Markosyan, Ashot; Route, Roger K.; Rowan, Sheila; Tornasi, Zeno
2016-03-01
Low mechanical loss at low temperatures and a high index of refraction should make silicon optimally suited for thermal noise reduction in highly reflective mirror coatings for gravitational wave detectors. However, due to high optical absorption, amorphous silicon (aSi) is unsuitable for being used as a direct high-index coating material to replace tantala. A possible solution is a multimaterial design, which enables exploitation of the excellent mechanical properties of aSi in the lower coating layers. The possible number of aSi layers increases with absorption reduction. In this work, the optimum heat treatment temperature of aSi deposited via ion-beam sputtering was investigated and found to be 450 °C . For this temperature, the absorption after deposition of a single layer of aSi at 1064 nm and 1550 nm was reduced by more than 80%.
13. Probing molecular chirality by coherent optical absorption spectra
SciTech Connect
Jia, W. Z.; Wei, L. F.
2011-11-15
We propose an approach to sensitively probe the chirality of molecules by measuring their coherent optical-absorption spectra. It is shown that quantum dynamics of the cyclic three-level chiral molecules driven by appropriately designed external fields is total-phase dependent. This will result in chirality-dependent absorption spectra for the probe field. As a consequence, the charality-dependent information in the spectra (such as the locations and relative heights of the characteristic absorption peaks) can be utilized to identify molecular chirality and determinate enantiomer excess (i.e., the percentages of different enantiomers). The feasibility of the proposal with chiral molecules confined in hollow-core photonic crystal fiber is also discussed.
14. Remark on: the neutron spherical optical-model absorption.
SciTech Connect
Smith, A. B.; Nuclear Engineering Division
2007-06-30
The energy-dependent behavior of the absorption term of the spherical neutron optical potential for doubly magic {sup 208}Pb and the neighboring {sup 209}Bi is examined. These considerations suggest a phenomenological model that results in an intuitively attractive energy dependence of the imaginary potential that provides a good description of the observed neutron cross sections and that is qualitatively consistent with theoretical concepts. At the same time it provides an alternative to some of the arbitrary assumptions involved in many conventional optical-model interpretations reported in the literature and reduces the number of the parameters of the model.
15. Ultraviolet optical absorptions of semiconducting copper phosphate glasses
NASA Technical Reports Server (NTRS)
Bae, Byeong-Soo; Weinberg, Michael C.
1993-01-01
Results are presented of a quantitative investigation of the change in UV optical absorption in semiconducting copper phosphate glasses with batch compositions of 40, 50, and 55 percent CuO, as a function of the Cu(2+)/Cu(total) ratio in the glasses for each glass composition. It was found that optical energy gap, E(opt), of copper phosphate glass is a function of both glass composition and Cu(2+)/Cu(total) ratio in the glass. E(opt) increases as the CuO content for fixed Cu(2+)/Cu(total) ratio and the Cu(2+)/Cu(total) ratio for fixed glass composition are reduced.
16. Study on the elemental mercury absorption cross section based on differential optical absorption spectroscopy
Zheng, Haiming; Yao, Penghui
2015-08-01
With the method of ultraviolet absorption spectrum, the exact absorption cross-section with the light source of the low-pressure mercury lamp was determined, during which the optimum wavelength for mercury concentrations inversion was 253.69 nm, the highest detection limit was 0.177 μg/cm3, and the lowest detection limit was 0.034 μg/cm3. Furthermore, based on the differential optical absorption spectroscopy(DOAS), the relationship between the integral parameters (IP) and the concentration as well as the signal-noise ration (SNR) under the conditions of gas flow was determined and the lowest detection limit was figured out to be 0.03524 μg/cm3, providing a method of DOAS to de-noise through the comparison between the mercury concentration values produced by DOAS and that produced by the wavelet de-noising method (db5). It turned out that the differential optical absorption spectroscopy had a strong anti-interference ability, while the wavelet de-noising method was not suitable for measuring the trace concentration change.
17. Optical absorption spectrum of Cu 2+ in calcium tartrate tetrahydrate
Swamy, Y. K. R.; Reddy, P. P.; Reddy, Y. P.
1980-02-01
Copper doped single crystals of calcium tartrate tetrahydrate are grown from silica gel. The optical absorption spectrum is investigated with polarised and unpolarised beams of incident light. The spectrum is attributed to the Cu 2+ ion in C 4V symmetry associated with spin-orbit coupling. The following crystal field parameters are evaluated: Dq = 1000 cm -1; λ = -830 cm -1; Ds = 1540 cm -1; Dt = 470 cm -1.
18. Electron paramagnetic resonance and optical absorption spectral studies on chalcocite
Reddy, S. Lakshmi; Fayazuddin, Md.; Frost, Ray L.; Endo, Tamio
2007-11-01
A chalcocite mineral sample of Shaha, Congo is used in the present study. An electron paramagnetic resonance (EPR) study on powdered sample confirms the presence of Mn(II), Fe(III) and Cu(II). Optical absorption spectrum indicates that Fe(III) impurity is present in octahedral structure whereas Cu(II) is present in rhombically distorted octahedral environment. Mid-infrared results are due to water and sulphate fundamentals.
19. Electron paramagnetic resonance and optical absorption spectral studies on chalcocite.
PubMed
Reddy, S Lakshmi; Fayazuddin, Md; Frost, Ray L; Endo, Tamio
2007-11-01
A chalcocite mineral sample of Shaha, Congo is used in the present study. An electron paramagnetic resonance (EPR) study on powdered sample confirms the presence of Mn(II), Fe(III) and Cu(II). Optical absorption spectrum indicates that Fe(III) impurity is present in octahedral structure whereas Cu(II) is present in rhombically distorted octahedral environment. Mid-infrared results are due to water and sulphate fundamentals. PMID:17324611
20. Estimation of aerosol optical properties considering hygroscopicity and light absorption
Jung, Chang Hoon; Lee, Ji Yi; Kim, Yong Pyo
2015-03-01
In this study, the influences of water solubility and light absorption on the optical properties of organic aerosols were investigated. A size-resolved model for calculating optical properties was developed by combining thermodynamic hygroscopic growth and aerosol dynamics models. The internal mixtures based on the homogeneous and core-shell mixing were compared. The results showed that the radiative forcing (RF) of Water Soluble Organic Carbon (WSOC) aerosol can be estimated to range from -0.07 to -0.49 W/m2 for core-shell mixing and from -0.09 to -0.47 W/m2 for homogeneous mixing under the simulation conditions (RH = 60%). The light absorption properties of WSOC showed the mass absorption efficiency (MAE) of WSOC can be estimated 0.43-0.5 m2/g, which accounts for 5-10% of the MAE of elemental carbon (EC). The effect on MAE of increasing the imaginary refractive index of WSOC was also calculated, and it was found that increasing the imaginary refractive index by 0.001i enhanced WSOC aerosol absorption by approximately 0.02 m2/g. Finally, the sensitivity test results revealed that changes in the fine mode fraction (FMF) and in the geometric mean diameter of the accumulation mode play important roles in estimating RF during hygroscopic growth.
1. Underwater optical wireless communications: depth dependent variations in attenuation.
PubMed
Johnson, Laura J; Green, Roger J; Leeson, Mark S
2013-11-20
Depth variations in the attenuation coefficient for light in the ocean were calculated using a one-parameter model based on the chlorophyll-a concentration C(c) and experimentally-determined Gaussian chlorophyll-depth profiles. The depth profiles were related to surface chlorophyll levels for the range 0-4 mg/m², representing clear, open ocean. The depth where C(c) became negligible was calculated to be shallower for places of high surface chlorophyll; 111.5 m for surface chlorophyll 0.8depth is the absolute minimum attenuation for underwater ocean communication links, calculated to be 0.0092 m⁻¹ at a wavelength of 430 nm. By combining this with satellite surface-chlorophyll data, it is possible to quantify the attenuation between any two locations in the ocean, with applications for low-noise or secure underwater communications and vertical links from the ocean surface. PMID:24513735
2. Assessment of 10 Year Record of Aerosol Optical Depth from OMI UV Observations
NASA Technical Reports Server (NTRS)
Ahn, Changwoo; Torres, Omar; Jethva, Hiren
2014-01-01
The Ozone Monitoring Instrument (OMI) onboard the EOS-Aura satellite provides information on aerosol optical properties by making use of the large sensitivity to aerosol absorption in the near-ultraviolet (UV) spectral region. Another important advantage of using near UV observations for aerosol characterization is the low surface albedo of all terrestrial surfaces in this spectral region that reduces retrieval errors associated with land surface reflectance characterization. In spite of the 13 × 24 square kilometers coarse sensor footprint, the OMI near UV aerosol algorithm (OMAERUV) retrieves aerosol optical depth (AOD) and single-scattering albedo under cloud-free conditions from radiance measurements at 354 and 388 nanometers. We present validation results of OMI AOD against space and time collocated Aerosol Robotic Network measured AOD values over multiple stations representing major aerosol episodes and regimes. OMAERUV's performance is also evaluated with respect to those of the Aqua-MODIS Deep Blue and Terra-MISR AOD algorithms over arid and semi-arid regions in Northern Africa. The outcome of the evaluation analysis indicates that in spite of the "row anomaly" problem, affecting the sensor since mid-2007, the long-term aerosol record shows remarkable sensor stability.
3. Axial resolution improvement in spectral domain optical coherence tomography using a depth-adaptive maximum-a-posterior framework
Boroomand, Ameneh; Tan, Bingyao; Wong, Alexander; Bizheva, Kostadinka
2015-03-01
The axial resolution of Spectral Domain Optical Coherence Tomography (SD-OCT) images degrades with scanning depth due to the limited number of pixels and the pixel size of the camera, any aberrations in the spectrometer optics and wavelength dependent scattering and absorption in the imaged object [1]. Here we propose a novel algorithm which compensates for the blurring effect of these factors of the depth-dependent axial Point Spread Function (PSF) in SDOCT images. The proposed method is based on a Maximum A Posteriori (MAP) reconstruction framework which takes advantage of a Stochastic Fully Connected Conditional Random Field (SFCRF) model. The aim is to compensate for the depth-dependent axial blur in SD-OCT images and simultaneously suppress the speckle noise which is inherent to all OCT images. Applying the proposed depth-dependent axial resolution enhancement technique to an OCT image of cucumber considerably improved the axial resolution of the image especially at higher imaging depths and allowed for better visualization of cellular membrane and nuclei. Comparing the result of our proposed method with the conventional Lucy-Richardson deconvolution algorithm clearly demonstrates the efficiency of our proposed technique in better visualization and preservation of fine details and structures in the imaged sample, as well as better speckle noise suppression. This illustrates the potential usefulness of our proposed technique as a suitable replacement for the hardware approaches which are often very costly and complicated.
4. Retrieval of Aerosol Optical Depth Under Thin Cirrus from MODIS: Application to an Ocean Algorithm
NASA Technical Reports Server (NTRS)
Lee, Jaehwa; Hsu, Nai-Yung Christina; Sayer, Andrew Mark; Bettenhausen, Corey
2013-01-01
A strategy for retrieving aerosol optical depth (AOD) under conditions of thin cirrus coverage from the Moderate Resolution Imaging Spectroradiometer (MODIS) is presented. We adopt an empirical method that derives the cirrus contribution to measured reflectance in seven bands from the visible to shortwave infrared (0.47, 0.55, 0.65, 0.86, 1.24, 1.63, and 2.12 µm, commonly used for AOD retrievals) by using the correlations between the top-of-atmosphere (TOA) reflectance at 1.38 micron and these bands. The 1.38 micron band is used due to its strong absorption by water vapor and allows us to extract the contribution of cirrus clouds to TOA reflectance and create cirrus-corrected TOA reflectances in the seven bands of interest. These cirrus-corrected TOA reflectances are then used in the aerosol retrieval algorithm to determine cirrus-corrected AOD. The cirrus correction algorithm reduces the cirrus contamination in the AOD data as shown by a decrease in both magnitude and spatial variability of AOD over areas contaminated by thin cirrus. Comparisons of retrieved AOD against Aerosol Robotic Network observations at Nauru in the equatorial Pacific reveal that the cirrus correction procedure improves the data quality: the percentage of data within the expected error +/-(0.03 + 0.05 ×AOD) increases from 40% to 80% for cirrus-corrected points only and from 80% to 86% for all points (i.e., both corrected and uncorrected retrievals). Statistical comparisons with Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) retrievals are also carried out. A high correlation (R = 0.89) between the CALIOP cirrus optical depth and AOD correction magnitude suggests potential applicability of the cirrus correction procedure to other MODIS-like sensors.
5. The matter power spectrum from the Lyα forest: an optical depth estimate
Zaroubi, S.; Viel, M.; Nusser, A.; Haehnelt, M.; Kim, T.-S.
2006-06-01
We measure the matter power spectrum from 31 Lyα spectra spanning the redshift range of 1.6-3.6. The optical depth, τ, for Lyα absorption of the intergalactic medium is obtained from the flux using the inversion method of Nusser & Haehnelt. The optical depth is converted to density by using a simple power-law relation, τ ~ (1 + δ)α. The non-linear 1D power spectrum of the gas density is then inferred with a method that makes simultaneous use of the one- and two-point statistics of the flux and compared against theoretical models with a likelihood analysis. A cold dark matter model with standard cosmological parameters fits the data well. The power-spectrum amplitude is measured to be (assuming a flat Universe), σ8 = (0.92 +/- 0.09) × (Ωm/0.3)-0.3, with α varying in the range of 1.56-1.8 with redshift. Enforcing the same cosmological parameters in all four redshift bins, the likelihood analysis suggests some evolution in the temperature-density relation and the thermal smoothing length of the gas. The inferred evolution is consistent with that expected if reionization of HeII occurred at z ~ 3.2. A joint analysis with the Wilkinson Microwave Anisotropy Probe results together with a prior on the Hubble constant as suggested by the Hubble Space Telescope key project data, yields values of Ωm and σ8 that are consistent with the cosmological concordance model. We also perform a further inversion to obtain the linear 3D power spectrum of the matter density fluctuations.
6. A Long-term Record of Saharan Dust Aerosol Properties from TOMS Observations: Optical Depth and Single Scattering Albedo
NASA Technical Reports Server (NTRS)
Torres, Omar; Bhartia, P. K.; Herman, J. R.; Einaudi, Franco (Technical Monitor)
2000-01-01
The interaction between the strong Rayleigh scattering in the near UV spectral region (330-380 nm) and the processes of aerosol absorption and scattering, produce a clear spectral signal in the upwelling radiance at the top of the atmosphere. This interaction is the basis of the TOMS (Total Ozone Mapping Spectrometer) aerosol retrieval technique that can be used for their characterization and to differentiate non-absorbing sulfates from strongly UV-absorbing aerosols such as mineral dust. For absorbing aerosols, the characterization is in terms of the optical depth and single scattering albedo with assumptions about the aerosol plume height. The results for non-absorbing aerosols are not dependent on plume height. Although iron compounds represent only between 5% to 8% of desert dust aerosol mass, hematite (Fe2O3) accounts for most of the near UV absorption. Because of the large ultraviolet absorption characteristic of hematite, the near UV method of aerosol sensing is especially suited for the detection and characterization of desert dust aerosols. Using the combined record of near UV measurements by the Nimbus7 (1978-1992) and Earth Probe (1996-present) TOMS instruments, a global longterm climatology of near UV optical depth and single scattering albedo has been produced. The multi-year long record of mineral aerosol properties over the area of influence of the Saharan desert, will be discussed.
7. Optical absorption of nanoporous silicon: quasiparticle band gaps and absorption spectra
Shi, Guangsha; Kioupakis, Emmanouil
2013-03-01
Silicon is an earth-abundant material of great importance in semiconductors electronics, but its photovoltaic applications are limited by the low absorption coefficient in the visible due to its indirect band gap. One strategy to improve the absorbance is to perforate silicon with nanoscale pores, which introduce carrier scattering that enables optical transitions across the indirect gap. We used density functional and many-body perturbation theory in the GW approximation to investigate the electronic and optical properties of porous silicon for various pore sizes, spacings, and orientations. Our calculations include up to 400 atoms in the unit cell. We will discuss the connection of the band-gap value and absorption coefficient to the underlying nanopore geometry. The absorption coefficient in the visible range is found to be optimal for appropriately chosen nanopore size, spacing, and orientation. Our work allows us to predict porous-silicon structures that may have optimal performance in photovoltaic applications. This research was supported as part of CSTEC, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science. Computational resources were provided by the DOE NERSC facility.
8. [Retrieval of monocyclic aromatic hydrocarbons with differential optical absorption spectroscopy].
PubMed
Xie, Pin-Hua; Fu, Qiang; Liu, Jian-Guo; Liu, Wen-Qing; Qin, Min; Li, Ang; Liu, Shi-Sheng; Wei, Qing-Nong
2006-09-01
Differential optical absorption spectroscopy (DOAS) technique has been used to measure trace gases in the atmosphere by their strongly structured absorption of radiation in the UV and visible spectral range, e. g. SO2, NO2, O3 etc. However, unlike the absorption spectra of SO2 and NO2, the analysis of aromatic compounds is difficult and strongly suffers from the cross interference of other absorbers (Herzberg bands of oxygen, ozone and sulfur dioxide), especially with relatively low concentrations of aromatic compounds in the atmosphere. In the present paper, the DOAS evaluation of aromatic compounds was performed by nonlinear least square fit with two interpolated oxygen optical density spectra at different path lengths and reference spectra of ozone at different temperature and SO2 cross section to correct the interference from absorbers of O2, O3 and SO2. The measurement of toluene, benzene, (m, p, o) xylene and phenol with a DOAS system showed that DOAS method is suitable for monocyclic aromatic compounds monitoring in the atmosphere. PMID:17112022
9. Combining energy and Laplacian regularization to accurately retrieve the depth of brain activity of diffuse optical tomographic data
Chiarelli, Antonio M.; Maclin, Edward L.; Low, Kathy A.; Mathewson, Kyle E.; Fabiani, Monica; Gratton, Gabriele
2016-03-01
Diffuse optical tomography (DOT) provides data about brain function using surface recordings. Despite recent advancements, an unbiased method for estimating the depth of absorption changes and for providing an accurate three-dimensional (3-D) reconstruction remains elusive. DOT involves solving an ill-posed inverse problem, requiring additional criteria for finding unique solutions. The most commonly used criterion is energy minimization (energy constraint). However, as measurements are taken from only one side of the medium (the scalp) and sensitivity is greater at shallow depths, the energy constraint leads to solutions that tend to be small and superficial. To correct for this bias, we combine the energy constraint with another criterion, minimization of spatial derivatives (Laplacian constraint, also used in low resolution electromagnetic tomography, LORETA). Used in isolation, the Laplacian constraint leads to solutions that tend to be large and deep. Using simulated, phantom, and actual brain activation data, we show that combining these two criteria results in accurate (error <2 mm) absorption depth estimates, while maintaining a two-point spatial resolution of <24 mm up to a depth of 30 mm. This indicates that accurate 3-D reconstruction of brain activity up to 30 mm from the scalp can be obtained with DOT.
10. Optical Absorption Spectra of Hydrous Wadsleyite to 32 GPa
Thomas, S.; Goncharov, A. F.; Jacobsen, S. D.; Bina, C. R.; Frost, D. J.
2009-05-01
Optical absorption spectra of high-pressure minerals can be used as indirect tools to calculate radiative conductivity of the Earth's interior [e.g., 1]. Recent high-pressure studies show that e.g. ringwoodite, γ-(Mg,Fe)2SiO4, does not become opaque in the near infrared and visible region, as previously assumed, but remains transparent to 21.5 GPa [2]. Therefore, it has been concluded that radiative heat transfer does not necessarily become blocked at high pressures of the mantle and ferromagnesian minerals actually could contribute to the heat flow in the Earth's interior [2]. In this study we use gem-quality single-crystals of hydrous Fe-bearing wadsleyite, β-(Mg,Fe)2SiO4, that were synthesized at 18 GPa and 1400 °C in a multianvil apparatus. Crystals were analyzed by Mössbauer and Raman spectroscopy, electron microprobe analysis and single-crystal X-ray diffraction. For absorption measurements a double-polished 50 μm sized single-crystal of wadsleyite was loaded in a diamond-anvil cell with neon as pressure medium. Optical absorption spectra were recorded at ambient conditions as well as up to 32 GPa from 400 to 50000 cm-1. At ambient pressure the absorption spectrum reveals two broad bands at - 10000 cm-1 and -15000 cm-1, and an absorption edge in the visible-ultraviolet range. With increasing pressure the absorption spectrum changes, both bands continuously shift to higher frequencies as has been observed for ringwoodite [2], but is contrary to earlier presumptions for wadsleyite [3]. Here, we will discuss band assignment along with the influence of iron, compare our results to previous absorption studies of mantle materials [2], and analyze possible implications for radiative conductivity of the transition zone. References: [1] Goncharov et al. (2008), McGraw Yearbook Sci. Tech., 242-245. [2] Keppler & Smyth (2005), Am. Mineral., 90 1209-1212. [3] Ross (1997), Phys. Chem. Earth, 22 113-118.
11. Effect of Thin Cirrus Clouds on Dust Optical Depth Retrievals From MODIS Observations
NASA Technical Reports Server (NTRS)
Feng, Qian; Hsu, N. Christina; Yang, Ping; Tsay, Si-Chee
2011-01-01
The effect of thin cirrus clouds in retrieving the dust optical depth from MODIS observations is investigated by using a simplified aerosol retrieval algorithm based on the principles of the Deep Blue aerosol property retrieval method. Specifically, the errors of the retrieved dust optical depth due to thin cirrus contamination are quantified through the comparison of two retrievals by assuming dust-only atmospheres and the counterparts with overlapping mineral dust and thin cirrus clouds. To account for the effect of the polarization state of radiation field on radiance simulation, a vector radiative transfer model is used to generate the lookup tables. In the forward radiative transfer simulations involved in generating the lookup tables, the Rayleigh scattering by atmospheric gaseous molecules and the reflection of the surface assumed to be Lambertian are fully taken into account. Additionally, the spheroid model is utilized to account for the nonsphericity of dust particles In computing their optical properties. For simplicity, the single-scattering albedo, scattering phase matrix, and optical depth are specified a priori for thin cirrus clouds assumed to consist of droxtal ice crystals. The present results indicate that the errors in the retrieved dust optical depths due to the contamination of thin cirrus clouds depend on the scattering angle, underlying surface reflectance, and dust optical depth. Under heavy dusty conditions, the absolute errors are comparable to the predescribed optical depths of thin cirrus clouds.
12. Micro-optical system based 3D imaging for full HD depth image capturing
Park, Yong-Hwa; Cho, Yong-Chul; You, Jang-Woo; Park, Chang-Young; Yoon, Heesun; Lee, Sang-Hun; Kwon, Jong-Oh; Lee, Seung-Wan
2012-03-01
20 Mega-Hertz-switching high speed image shutter device for 3D image capturing and its application to system prototype are presented. For 3D image capturing, the system utilizes Time-of-Flight (TOF) principle by means of 20MHz high-speed micro-optical image modulator, so called 'optical shutter'. The high speed image modulation is obtained using the electro-optic operation of the multi-layer stacked structure having diffractive mirrors and optical resonance cavity which maximizes the magnitude of optical modulation. The optical shutter device is specially designed and fabricated realizing low resistance-capacitance cell structures having small RC-time constant. The optical shutter is positioned in front of a standard high resolution CMOS image sensor and modulates the IR image reflected from the object to capture a depth image. Suggested novel optical shutter device enables capturing of a full HD depth image with depth accuracy of mm-scale, which is the largest depth image resolution among the-state-of-the-arts, which have been limited up to VGA. The 3D camera prototype realizes color/depth concurrent sensing optical architecture to capture 14Mp color and full HD depth images, simultaneously. The resulting high definition color/depth image and its capturing device have crucial impact on 3D business eco-system in IT industry especially as 3D image sensing means in the fields of 3D camera, gesture recognition, user interface, and 3D display. This paper presents MEMS-based optical shutter design, fabrication, characterization, 3D camera system prototype and image test results.
13. Optical Hydrogen Absorption Consistent with a Bow Shock Leading the Hot Jupiter HD 189733b
Cauley, Paul Wilson; Redfield, Seth; Jensen, Adam
2015-08-01
Bow shocks are ubiquitous astrophysical phenomena resulting from the supersonic passage of an object through a gas. Recently, pre-transit absorption in UV metal transitions of the hot Jupiter exoplanets HD 189733b and WASP12-b have been interpreted as being caused by material compressed in a planetary bow shock. Here we present a robust detection of a time-resolved pre-transit, as well as in-transit, absorption signature around the hot Jupiter exoplanet HD 189733b using high spectral resolution observations of several hydrogen Balmer lines. The line shape of the pre-transit feature and the shape of the time series absorption provide the strongest constraints on the morphology and physical characteristics of extended structures around an exoplanet. The in-transit measurements confirm the exospheric Hα detection of Jensen et al. (2012) although the absorption depth measured here is ~50% lower. The pre-transit absorption feature occurs 125 minutes before the predicted optical transit, a projected linear distance to the stellar disk of 7.2 Rp. The absorption strength observed in the Balmer lines indicates an optically thick, but physically small, geometry. We model this signal as the early ingress of a planetary bow shock. If the bow shock is mediated by a planetary magnetosphere, the large standoff distance derived from the model suggests a large planetary magnetic field strength. Better knowledge of exoplanet magnetic field strengths is crucial to understanding the role these fields play in star-planet interactions and protecting planets in the habitable zone from dangerous stellar flares.
14. Retrieval of the optical depth using an all-sky CCD camera.
PubMed
Olmo, Francisco J; Cazorla, Alberto; Alados-Arboledas, Lucas; López-Alvarez, Miguel A; Hernández-Andrés, Javier; Romero, Javier
2008-12-01
A new method is presented for retrieval of the aerosol and cloud optical depth using a CCD camera equipped with a fish-eye lens (all-sky imager system). In a first step, the proposed method retrieves the spectral radiance from sky images acquired by the all-sky imager system using a linear pseudoinverse algorithm. Then, the aerosol or cloud optical depth at 500 nm is obtained as that which minimizes the residuals between the zenith spectral radiance retrieved from the sky images and that estimated by the radiative transfer code. The method is tested under extreme situations including the presence of nonspherical aerosol particles. The comparison of optical depths derived from the all-sky imager with those retrieved with a sunphotometer operated side by side shows differences similar to the nominal error claimed in the aerosol optical depth retrievals from sunphotometer networks. PMID:19037341
15. A COMPARISON OF AEROSOL OPTICAL DEPTH SIMULATED USING CMAQ WITH SATELLITE ESTIMATES
EPA Science Inventory
Satellite data provide new opportunities to study the regional distribution of particulate matter. The aerosol optical depth (AOD) - a derived estimate from the satellite measured irradiance, can be compared against model derived estimate to provide an evaluation of the columnar ...
16. Temporal variations in atmospheric water vapor and aerosol optical depth determined by remote sensing
NASA Technical Reports Server (NTRS)
Pitts, D. E.; Mcallum, W. E.; Heidt, M.; Jeske, K.; Lee, J. T.; Demonbrun, D.; Morgan, A.; Potter, J.
1977-01-01
By automatically tracking the sun, a four-channel solar radiometer was used to continuously measure optical depth and atmospheric water vapor. The design of this simple autotracking solar radiometer is presented. A technique for calculating the precipitable water from the ratio of a water band to a nearby nonabsorbing band is discussed. Studies of the temporal variability of precipitable water and atmospheric optical depth at 0.610, 0.8730 and 1.04 microns are presented. There was good correlation between the optical depth measured using the autotracker and visibility determined from National Weather Service Station data. However, much more temporal structure was evident in the autotracker data than in the visibility data. Cirrus clouds caused large changes in optical depth over short time periods. They appear to be the largest deleterious atmospheric effect over agricultural areas that are remote from urban pollution sources.
17. Comparison of Cirrus height and optical depth derived from satellite and aircraft measurements
SciTech Connect
Kastner, M.; Kriebel, K.T.; Meerkoetter, R.; Renger, W.; Ruppersberg, G.H.; Wendling, P. )
1993-10-01
During the International Cirrus Experiment (ICE'89) simultaneous measurements of cirrus cloud-top height and optical depth by satellite and aircraft have been taken. Data from the Advanced Very High Resolution Radiometer (AVHRR) onboard the NOAA polar-orbiting meteorological satellite system have been used together with the algorithm package AVHRR processing scheme over clouds, land and ocean (APOLLO) to derive optical depth. NOAA High-Resolution Infrared Radiation Sounder (HIRS) data have been used together with a bispectral technique to derive cloud-top height. Also, the optical depth of some contrails could be estimated. Airborne measurements have been performed simultaneously by using the Airborne Lidar Experiment (ALEX), a backscatter lidar. Comparison of satellite data with airborne data showed agreement of the top heights to about 500 m and of the optical depths to about 30%. These uncertainties are within the limits obtained from error estimates. 34 refs., 8 figs.
18. Absorptance Measurements of Optical Coatings - A Round Robin
SciTech Connect
Chow, R; Taylor, J R; Wu, Z L; Boccara, C A; Broulik, U; Commandre, M; DiJon, J; Fleig, C; Giesen, A; Fan, Z X; Kuo, P K; Lalezari, R; Moncur, K; Obramski, H-J; Reicher, D; Ristau, D; Roche, P; Steiger, B; Thomsen, M; von Gunten, M
2000-10-26
An international round robin study was conducted on the absorption measurement of laser-quality coatings. Sets of optically coated samples were made by a ''reactive DC magnetron'' sputtering and an ion beam sputtering deposition process. The sample set included a high reflector at 514 nm and a high reflector for the near infrared (1030 to 1318 nm), single layers of silicon dioxide, tantalum pentoxide, and hafnium dioxide. For calibration purposes, a sample metalized with hafnium and an uncoated, superpolished fused silica substrate were also included. The set was sent to laboratory groups for absorptance measurement of these coatings. Whenever possible, each group was to measure a common, central area and another area specifically assigned to the respective group. Specific test protocols were also suggested in regards to the laser exposure time, power density, and surface preparation.
19. Optical Path Switching Based Differential Absorption Radiometry for Substance Detection
NASA Technical Reports Server (NTRS)
Sachse, Glen W. (Inventor)
2000-01-01
A system and method are provided for detecting one or more substances. An optical path switch divides sample path radiation into a time series of alternating first polarized components and second polarized components. The first polarized components are transmitted along a first optical path and the second polarized components along a second optical path. A first gasless optical filter train filters the first polarized components to isolate at least a first wavelength band thereby generating first filtered radiation. A second gasless optical filter train filters the second polarized components to isolate at least a second wavelength band thereby generating second filtered radiation. The first wavelength band and second wavelength band are unique. Further, spectral absorption of a substance of interest is different at the first wavelength band as compared to the second wavelength band. A beam combiner combines the first and second filtered radiation to form a combined beam of radiation. A detector is disposed to monitor magnitude of at least a portion of the combined beam alternately at the first wavelength band and the second wavelength band as an indication of the concentration of the substance in the sample path.
20. Tuning nonlinear optical absorption properties of WS2 nanosheets
Long, Hui; Tao, Lili; Tang, Chun Yin; Zhou, Bo; Zhao, Yuda; Zeng, Longhui; Yu, Siu Fung; Lau, Shu Ping; Chai, Yang; Tsang, Yuen Hong
2015-10-01
To control the optical properties of two-dimensional (2D) materials is a long-standing goal, being of both fundamental and technological significance. Tuning nonlinear optical absorption (NOA) properties of 2D transition metal dichalcogenides in a cost effective way has emerged as an important research topic because of its possibility to custom design NOA properties, implying enormous applications including optical computers, communications, bioimaging, and so on. In this study, WS2 with different size and thickness distributions was fabricated. The results demonstrate that both NOA onset threshold, FON, and optical limiting threshold, FOL, of WS2 under the excitation of a nanosecond pulsed laser can be tuned over a wide range by controlling its size and thickness. The FON and FOL show a rapid decline with the decrease of size and thickness. Due to the edge and quantum confinement effect, WS2 quantum dots (2.35 nm) exhibit the lowest FON (0.01 J cm-2) and FOL (0.062 J cm-2) among all the samples, which are comparable to the lowest threshold achieved in graphene based materials, showing great potential as NOA materials with tunable properties.To control the optical properties of two-dimensional (2D) materials is a long-standing goal, being of both fundamental and technological significance. Tuning nonlinear optical absorption (NOA) properties of 2D transition metal dichalcogenides in a cost effective way has emerged as an important research topic because of its possibility to custom design NOA properties, implying enormous applications including optical computers, communications, bioimaging, and so on. In this study, WS2 with different size and thickness distributions was fabricated. The results demonstrate that both NOA onset threshold, FON, and optical limiting threshold, FOL, of WS2 under the excitation of a nanosecond pulsed laser can be tuned over a wide range by controlling its size and thickness. The FON and FOL show a rapid decline with the decrease of size
1. Photoacoustic determination of optical absorption to extinction ratio in aerosols.
PubMed
Roessler, D M; Faxvog, F R
1980-02-15
The photoacoustic technique has been used in conjunction with an optical transmission measurement to determine the fraction of light absorbed in cigarette and acetylene smoke aerosols. At 0.5145-microm wavelength,the absorption-to-extinction fraction is 0.01 +/- 0.003 for cigarette smoke and is in excellent agreement with predictions from Mie theory for smoke particles having a refractive index of 1.45-0.00133i and a median diameter in the 0.15-0.65-microm range. For acetylene smoke the absorbed fraction was 0.85 +/- 0.05. PMID:20216896
2. Optical absorption and scattering spectra of pathological stomach tissues
Giraev, K. M.; Ashurbekov, N. A.; Lakhina, M. A.
2011-03-01
Diffuse reflection spectra of biotissues in vivo and transmission and reflection coefficients for biotissues in vitro are measured over 300-800 nm. These data are used to determine the spectral absorption and scattering indices and the scattering anisotropy factor for stomach mucous membranes under normal and various pathological conditions (chronic atrophic and ulcerous defects, malignant neoplasms). The most importan tphysiological (hemodynamic and oxygenation levels) and structural-morphological (scatterer size and density) parameters are also determined. The results of a morphofunctional study correlate well with the optical properties and are consistent with data from a histomorphological analysis of the corresponding tissues.
3. Using a piezoelectric fiber stretcher to remove the depth ambiguity in optical Fourier domain imaging
Vergnole, Sébastien; Lamouche, Guy; Dufour, Marc; Gauthier, Bruno
2007-07-01
This paper reports the study of an Optical Fourier Domain Imaging (OFDI) setup for optical coherence tomography. One of the main drawbacks of OFDI is its inability to differentiate positive and negative depths. Some setups have already been proposed to remove this depth ambiguity by introducing a modulation by means of electro-optic or acousto-optic modulators. In our setup, we implement a piezoelectric fiber stretcher to generate a periodic phase shift between successive A-scans, thus introducing a transverse modulation. The depth ambiguity is then resolved by performing a Fourier treatment in the transverse direction before processing the data in the axial direction. It is similar to the B-M mode scanning already proposed for Spectral-Domain OCT1 but with a more efficient experimental setup. We discuss the advantages and the drawbacks of our technique compared to the technique based on acousto-optics modulators by comparing images of an onion obtained with both techniques.
4. Extending differential optical absorption spectroscopy for limb measurements in the UV
Puä·Ä«Te, J.; Kühl, S.; Deutschmann, T.; Platt, U.; Wagner, T.
2009-11-01
Methods of UV/VIS absorption spectroscopy to determine the constituents in the Earth's atmosphere from measurements of scattered light are often based on the Beer-Lambert law, like e.g. Differential Optical Absorption Spectroscopy (DOAS). Therefore they are strictly valid for weak absorptions and narrow wavelength intervals (strictly only for monochromatic radiation). For medium and strong absorption (e.g. along very long light-paths like in limb geometry) the relation between the optical depth and the concentration of an absorber is not linear anymore. As well, for large wavelength intervals the wavelength dependent differences in the travelled light-paths become important, especially in the UV, where the probability for scattering increases strongly with decreasing wavelength. However, by taking into account these dependencies, the applicability of the DOAS method can be extended also to cases with medium to strong absorptions and for broader wavelength intervals. Common approaches for this correction are the so called air mass factor modified (or extended) DOAS and the weighting function modified DOAS. These approaches take into account the wavelength dependency of the slant column densities (SCDs), but also require a-priori knowledge for the air mass factor or the weighting function calculation by radiative transfer modelling. We describe an approach that considers the fitting results obtained from DOAS, the SCDs, as a function of wavelength and vertical optical depth and expands this function into a Taylor series of both quantities. The Taylor coefficients are then applied as additional fitting parameters in the DOAS analysis. Thus the variability of the SCD in the fit window is determined by the retrieval itself. This new approach gives a description of the SCD that is as close to reality as desired (depending on the order of the Taylor expansion), and is independent from any assumptions or a-priori knowledge of the considered absorbers. In case studies for
5. Fine Structure and Optical Depth in the Solar Transition Region
Plovanic, Jacob; Kankelborg, C. C.; Williamson, K.
2011-05-01
Unresolved fine structure in the solar transition region (TR) has long been inferred from measurements of density-sensitive line pairs showing low filling factor (< 0.01). Low filling factor models for the structure of the He II source region, however, have not been well studied. We propose a highly structured model of the lower atmosphere in which He II is formed at low filling factors, leading to high emission measure and an optically thin He II line. This transparent TR material is juxtaposed with absorbing chromospheric structures, leading to the nearly uniform center to limb behavior of the He II line as observed.
6. All-optical reservoir computer based on saturation of absorption.
PubMed
Dejonckheere, Antoine; Duport, François; Smerieri, Anteo; Fang, Li; Oudar, Jean-Louis; Haelterman, Marc; Massar, Serge
2014-05-01
Reservoir computing is a new bio-inspired computation paradigm. It exploits a dynamical system driven by a time-dependent input to carry out computation. For efficient information processing, only a few parameters of the reservoir needs to be tuned, which makes it a promising framework for hardware implementation. Recently, electronic, opto-electronic and all-optical experimental reservoir computers were reported. In those implementations, the nonlinear response of the reservoir is provided by active devices such as optoelectronic modulators or optical amplifiers. By contrast, we propose here the first reservoir computer based on a fully passive nonlinearity, namely the saturable absorption of a semiconductor mirror. Our experimental setup constitutes an important step towards the development of ultrafast low-consumption analog computers. PMID:24921786
7. Graphical aerosol classification method using aerosol relative optical depth
Chen, Qi-Xiang; Yuan, Yuan; Shuai, Yong; Tan, He-Ping
2016-06-01
A simple graphical method is presented to classify aerosol types based on a combination of aerosol optical thickness (AOT) and aerosol relative optical thickness (AROT). Six aerosol types, including maritime (MA), desert dust (DD), continental (CO), sub-continental (SC), urban industry (UI) and biomass burning (BB), are discriminated in a two dimensional space of AOT440 and AROT1020/440. Numerical calculations are performed using MIE theory based on a multi log-normal particle size distribution, and the AROT ranges for each aerosol type are determined. More than 5 years of daily observations from 8 representative aerosol sites are applied to the method to confirm spatial applicability. Finally, 3 individual cases are analyzed according to their specific aerosol status. The outcomes indicate that the new graphical method coordinates well with regional characteristics and is also able to distinguish aerosol variations in individual situations. This technique demonstrates a novel way to estimate different aerosol types and provide information on radiative forcing calculations and satellite data corrections.
8. Mars Orbiter Laser Altimeter Radiometry: Phase Functions and the Optical Depth of Nocturnal Water Ice Clouds
Neumann, G. A.; Barker, M. K.; Sun, X.
2014-12-01
Over the course of more than 3 Mars years the MOLA instrument on board Mars Global Surveyor (from 1999 to the loss of MGS in Nov. 2006) obtained passive reflectance measurements of Mars at 1064 nm wavelength from the solar background. As an altimeter, the quantity of light removed from a laser beam by scattering or absorption during the roundtrip to the surface may be calculated knowing the energy returned, the surface geometric albedo and the instrument parameters for each laser shot. These opacity measurements indicate the combined effects of dust and condensates, particularly those seen during during the night. The measure of opacity, to optical depths exceeding unity, correlates well with daytime measurements by the Hubble Space Telescope and with the broadband Thermal Emission Spectrometer. Applying a simple phase function to passive radiometric observations obtained at emission angles varying from 0 to 80 degrees, upper and lower limits are obtained for atmospheric opacity as a function of season and time of day. The implications for the effects of nocturnal water ice clouds on radiative transfer, and for future applications to the detection of icy plumes from moons of the outer solar system will be discussed.
9. Improving Calculation Accuracies of Accumulation-Mode Fractions Based on Spectral of Aerosol Optical Depths
Ying, Zhang; Zhengqiang, Li; Yan, Wang
2014-03-01
Anthropogenic aerosols are released into the atmosphere, which cause scattering and absorption of incoming solar radiation, thus exerting a direct radiative forcing on the climate system. Anthropogenic Aerosol Optical Depth (AOD) calculations are important in the research of climate changes. Accumulation-Mode Fractions (AMFs) as an anthropogenic aerosol parameter, which are the fractions of AODs between the particulates with diameters smaller than 1μm and total particulates, could be calculated by AOD spectral deconvolution algorithm, and then the anthropogenic AODs are obtained using AMFs. In this study, we present a parameterization method coupled with an AOD spectral deconvolution algorithm to calculate AMFs in Beijing over 2011. All of data are derived from AErosol RObotic NETwork (AERONET) website. The parameterization method is used to improve the accuracies of AMFs compared with constant truncation radius method. We find a good correlation using parameterization method with the square relation coefficient of 0.96, and mean deviation of AMFs is 0.028. The parameterization method could also effectively solve AMF underestimate in winter. It is suggested that the variations of Angstrom indexes in coarse mode have significant impacts on AMF inversions.
10. Importance of representing optical depth variability for estimates of global line-shaped contrail radiative forcing
PubMed Central
Kärcher, Bernd; Burkhardt, Ulrike; Ponater, Michael; Frömming, Christine
2010-01-01
Estimates of the global radiative forcing by line-shaped contrails differ mainly due to the large uncertainty in contrail optical depth. Most contrails are optically thin so that their radiative forcing is roughly proportional to their optical depth and increases with contrail coverage. In recent assessments, the best estimate of mean contrail radiative forcing was significantly reduced, because global climate model simulations pointed at lower optical depth values than earlier studies. We revise these estimates by comparing the probability distribution of contrail optical depth diagnosed with a climate model with the distribution derived from a microphysical, cloud-scale model constrained by satellite observations over the United States. By assuming that the optical depth distribution from the cloud model is more realistic than that from the climate model, and by taking the difference between the observed and simulated optical depth over the United States as globally representative, we quantify uncertainties in the climate model’s diagnostic contrail parameterization. Revising the climate model results accordingly increases the global mean radiative forcing estimate for line-shaped contrails by a factor of 3.3, from 3.5 mW/m2 to 11.6 mW/m2 for the year 1992. Furthermore, the satellite observations and the cloud model point at higher global mean optical depth of detectable contrails than often assumed in radiative transfer (off-line) studies. Therefore, we correct estimates of contrail radiative forcing from off-line studies as well. We suggest that the global net radiative forcing of line-shaped persistent contrails is in the range 8–20 mW/m2 for the air traffic in the year 2000. PMID:20974909
11. Importance of representing optical depth variability for estimates of global line-shaped contrail radiative forcing.
PubMed
Kärcher, Bernd; Burkhardt, Ulrike; Ponater, Michael; Frömming, Christine
2010-11-01
Estimates of the global radiative forcing by line-shaped contrails differ mainly due to the large uncertainty in contrail optical depth. Most contrails are optically thin so that their radiative forcing is roughly proportional to their optical depth and increases with contrail coverage. In recent assessments, the best estimate of mean contrail radiative forcing was significantly reduced, because global climate model simulations pointed at lower optical depth values than earlier studies. We revise these estimates by comparing the probability distribution of contrail optical depth diagnosed with a climate model with the distribution derived from a microphysical, cloud-scale model constrained by satellite observations over the United States. By assuming that the optical depth distribution from the cloud model is more realistic than that from the climate model, and by taking the difference between the observed and simulated optical depth over the United States as globally representative, we quantify uncertainties in the climate model's diagnostic contrail parameterization. Revising the climate model results accordingly increases the global mean radiative forcing estimate for line-shaped contrails by a factor of 3.3, from 3.5 mW/m(2) to 11.6 mW/m(2) for the year 1992. Furthermore, the satellite observations and the cloud model point at higher global mean optical depth of detectable contrails than often assumed in radiative transfer (off-line) studies. Therefore, we correct estimates of contrail radiative forcing from off-line studies as well. We suggest that the global net radiative forcing of line-shaped persistent contrails is in the range 8-20 mW/m(2) for the air traffic in the year 2000. PMID:20974909
12. Extending differential optical absorption spectroscopy for limb measurements in the UV
Puä·Ä«Te, J.; Kühl, S.; Deutschmann, T.; Platt, U.; Wagner, T.
2010-05-01
Methods of UV/VIS absorption spectroscopy to determine the constituents in the Earth's atmosphere from measurements of scattered light are often based on the Beer-Lambert law, like e.g. Differential Optical Absorption Spectroscopy (DOAS). While the Beer-Lambert law is strictly valid for a single light path only, the relation between the optical depth and the concentration of any absorber can be approximated as linear also for scattered light observations at a single wavelength if the absorption is weak. If the light path distribution is approximated not to vary with wavelength, also linearity between the optical depth and the product of the cross-section and the concentration of an absorber can be assumed. These assumptions are widely made for DOAS applications for scattered light observations. For medium and strong absorption of scattered light (e.g. along very long light-paths like in limb geometry) the relation between the optical depth and the concentration of an absorber is no longer linear. In addition, for broad wavelength intervals the differences in the travelled light-paths at different wavelengths become important, especially in the UV, where the probability for scattering increases strongly with decreasing wavelength. However, the DOAS method can be extended to cases with medium to strong absorptions and for broader wavelength intervals by the so called air mass factor modified (or extended) DOAS and the weighting function modified DOAS. These approaches take into account the wavelength dependency of the slant column densities (SCDs), but also require a priori knowledge for the air mass factor or the weighting function from radiative transfer modelling. We describe an approach that considers the fitting results obtained from DOAS, the SCDs, as a function of wavelength and vertical optical depth and expands this function into a Taylor series of both quantities. The Taylor coefficients are then applied as additional fitting parameters in the DOAS analysis
13. Tuning nonlinear optical absorption properties of WS₂ nanosheets.
PubMed
Long, Hui; Tao, Lili; Tang, Chun Yin; Zhou, Bo; Zhao, Yuda; Zeng, Longhui; Yu, Siu Fung; Lau, Shu Ping; Chai, Yang; Tsang, Yuen Hong
2015-11-14
To control the optical properties of two-dimensional (2D) materials is a long-standing goal, being of both fundamental and technological significance. Tuning nonlinear optical absorption (NOA) properties of 2D transition metal dichalcogenides in a cost effective way has emerged as an important research topic because of its possibility to custom design NOA properties, implying enormous applications including optical computers, communications, bioimaging, and so on. In this study, WS2 with different size and thickness distributions was fabricated. The results demonstrate that both NOA onset threshold, F(ON), and optical limiting threshold, F(OL), of WS2 under the excitation of a nanosecond pulsed laser can be tuned over a wide range by controlling its size and thickness. The F(ON) and F(OL) show a rapid decline with the decrease of size and thickness. Due to the edge and quantum confinement effect, WS2 quantum dots (2.35 nm) exhibit the lowest F(ON) (0.01 J cm(-2)) and F(OL) (0.062 J cm(-2)) among all the samples, which are comparable to the lowest threshold achieved in graphene based materials, showing great potential as NOA materials with tunable properties. PMID:26456545
14. Impact of inhomogeneous optical scattering coefficient distribution on recovery of optical absorption coefficient maps using tomographic photoacoustic data
Li, Xiaoqi; Jiang, Huabei
2013-02-01
We present a study through extensive simulation that considers the impact of inhomogeneous optical scattering coefficient distribution on recovery of optical absorption coefficient maps using tomographic photoacoustic data collected from media mimicking breast tissue. We found that while the impact of scattering heterogeneities/targets is modest on photoacoustic recovery of optical absorption coefficients, the impact of scattering contrast caused by adipose tissue, a layer of normal tissue along the boundary of the breast, is dramatic on reconstruction of optical absorption coefficients using photoacoustic data—up to 25.8% relative error in recovering the absorption coefficient is estimated in such cases. To overcome this problem, we propose a new method to enhance photoacoustic recovery of the optical absorption coefficient in heterogeneous media by considering inhomogeneous scattering coefficient distribution provided by diffuse optical tomography (DOT). Results from extensive simulations show that photoacoustic recovery of absorption coefficient maps can be improved considerably with a priori scattering information from DOT.
15. Nonlinear dynamics of optical absorption of intense beams
Corbett, D.; van Oosten, C. L.; Warner, M.
2008-07-01
On traversing materials with absorbing dyes, weak optical beams decay exponentially (a Beer profile), while intense beams develop in time a profile that is spatially linear until at great depth it becomes spatially exponential. This anomalous, deep penetration, due to photobleaching of surface layers, is important for heavy dye loading and intense beams, for instance in photo-actuation. We address the problem of the evolution in time from initial Beer’s Law to a finally deeply-penetrating optical profile in dyes. Our largely analytic solution of the coupled, nonlinear, partial differential equations governing the spatiotemporal decay of the Poynting flux and the nonlinear population dynamics of the photo-active molecules under intense irradiation has application to optomechanical devices.
16. Metal incorporated M-DNA: structure, magnetism, optical absorption
Mizoguchi, Kenji
2011-09-01
DNA is an interesting material from the viewpoint of the materials science. This paper discusses the electronic states of the metal incorporated M-DNA complexes with several species of metal ions. M-DNA prepared by the ordinary methanol precipitation technique has been investigated with ESR, STM and optical absorption, and concluded that the metal ion hydrated with several water molecules locates in between the bases of a base pair and that the divalent metal ions are incorporated into DNA in place of two Na cations as the counter ion for PO-4in the DNA backbones. Only in Fe-DNA, it was confirmed that the Fe2+ in the FeCl2 aqueous solution reacts with DNA to form Fe-DNA complex with Fe3+, where the charge would transfer to DNA. Within 30 min, the hydrolysis of Fe2+ to form Fe3+O(OH) did not occur in the FeCl2 aqueous solution at room temperature. The optical absorption spectra of Fe-DNA is similar to that for FeCl3 with the ionic character, but definitely differs from that of Fe3+O(OH) with the covalent bonding nature, suggesting the ionic character of Fe3+ in Fe-DNA. Finally, the possible two kinds of electronic states for Zn-DNA with different bonding nature will be discussed in relation to the recent report on Zn-DNA.
17. In vivo photothermal optical coherence tomography for non-invasive imaging of endogenous absorption agents
PubMed Central
Makita, Shuichi; Yasuno, Yoshiaki
2015-01-01
In vivo photothermal optical coherence tomography (OCT) is demonstrated for cross-sectional imaging of endogenous absorption agents. In order to compromise the sensitivity, imaging speed, and sample motion immunity, a new photothermal detection scheme and phase processing method are developed. Phase-resolved swept-source OCT and fiber-pigtailed laser diode (providing excitation at 406 nm) are combined to construct a high-sensitivity photothermal OCT system. OCT probe and excitation beam coaxially illuminate and are focused on tissues. The photothermal excitation and detection procedure is designed to obtain high efficiency of photothermal effect measurement. The principle and method of depth-resolved cross-sectional imaging of absorption agents with photothermal OCT has been derived. The phase-resolved thermal expansion detection algorithm without motion artifact enables in vivo detection of photothermal effect. Phantom imaging with a blood phantom and in vivo human skin imaging are conducted. A phantom with guinea-pig blood as absorber has been scanned by the photothermal OCT system to prove the concept of cross-sectional absorption agent imaging. An in vivo human skin measurement is also performed with endogenous absorption agents. PMID:26137374
18. Chemical state of Ag in Conducting Bridge Random Access Memory cells: a depth resolved X-ray Absorption Spectroscopy investigation.
d'Acapito, F.; Souchier, E.; Noe, P.; Blaise, P.; Bernard, M.; Jousseaume, V.
2016-05-01
Conducting Bridge Random Access Memories (CBRAM) are a promising substitute for FLASH technology but problems with limited retention of the low resistance ON state still hamper their massive deployment. Depth resolved X-ray Absorption Spectroscopy has been used to describe the chemical state of the atoms of the active electrode (in this case Ag) and to reveal the role of Sb as stabilizer of the metallic state.
19. Cloud Optical Depth Retrievals from Solar Background "signal" of Micropulse Lidars
NASA Technical Reports Server (NTRS)
Chiu, J. Christine; Marshak, A.; Wiscombe, W.; Valencia, S.; Welton, E. J.
2007-01-01
Pulsed lidars are commonly used to retrieve vertical distributions of cloud and aerosol layers. It is widely believed that lidar cloud retrievals (other than cloud base altitude) are limited to optically thin clouds. Here we demonstrate that lidars can retrieve optical depths of thick clouds using solar background light as a signal, rather than (as now) merely a noise to be subtracted. Validations against other instruments show that retrieved cloud optical depths agree within 10-15% for overcast stratus and broken clouds. In fact, for broken cloud situations one can retrieve not only the aerosol properties in clear-sky periods using lidar signals, but also the optical depth of thick clouds in cloudy periods using solar background signals. This indicates that, in general, it may be possible to retrieve both aerosol and cloud properties using a single lidar. Thus, lidar observations have great untapped potential to study interactions between clouds and aerosols.
20. Development and evaluation of optical needle depth sensor for percutaneous diagnosis and therapies
Palmer, Keryn; Alelyunas, David; McCann, Connor; Yoshimitsu, Kitaro; Kato, Takahisa; Song, Sang-Eun; Hata, Nobuhiko
2014-03-01
Current methods of needle insertion during percutaneous CT and MRI guided procedures lack precision in needle depth sensing. The depth of the needle insertion is currently monitored through depth markers drawn on the needle and later confirmed by intra-procedural imaging; until this confirmation, the physicians' judgment that the target is reached is solely based on the depth markers, which are not always clearly visible. We have therefore designed an optical sensing device which provides continuous feedback of needle insertion depth and degree of rotation throughout insertion. An optical mouse sensor was used in conjunction with a microcontroller board, Arduino Due, to acquire needle position information. The device is designed to be attached to a needle guidance robot developed for MRI-guided prostate biopsy in order to aid the manual insertion. An LCD screen and three LEDs were employed with the Arduino Due to form a hand-held device displaying needle depth and rotation. Accuracy of the device was tested to evaluate the impact of insertion speed and rotation. Unlike single dimensional needle depth sensing developed by other researchers, this two dimensional sensing device can also detect the rotation around the needle axis. The combination of depth and rotation sensing would be greatly beneficial for the needle steering approaches that require both depth and rotation information. Our preliminary results indicate that this sensing device can be useful in detecting needle motion when using an appropriate speed and range of motion.
1. Ocean color patterns help to predict depth of optical layers in stratified coastal waters
Montes-Hugo, Martín A.; Weidemann, Alan; Gould, Richard; Arnone, Robert; Churnside, James H.; Jaroz, Ewa
2011-01-01
Subsurface optical layers distributed at two different depths were investigated in Monterrey Bay, East Sound, and the Black Sea based on spatial statistics of remote sensing reflectance (Rrs). The main objective of this study was to evaluate the use of Rrs(443)/Rrs(490) (hereafter R1) skewness (ψ) as an indicator of vertical optical structure in different marine regions. Measurements of inherent optical properties were obtained using a remotely operated towed vehicle and R1 was theoretically derived from optical profiles. Although the broad range of trophic status and water stratification, a common statistical pattern consisting of lower ψR1--a deeper optical layer was found in all study cases. This variation was attributed to optical changes above the opticline and related to horizontal variability of particulates and spectral variations with depth. We recommend more comparisons in stratified coastal waters with different phytoplankton communities before the use of ψR1 can be generalized as a noninvasive optical proxy for screening depth changes on subsurface optical layers.
2. Photothermal optical coherence tomography for depth-resolved imaging of mesenchymal stem cells via single wall carbon nanotubes
Subhash, Hrebesh M.; Connolly, Emma; Murphy, Mary; Barron, Valerie; Leahy, Martin
2014-03-01
The progress in stem cell research over the past decade holds promise and potential to address many unmet clinical therapeutic needs. Tracking stem cell with modern imaging modalities are critically needed for optimizing stem cell therapy, which offers insight into various underlying biological processes such as cell migration, engraftment, homing, differentiation, and functions etc. In this study we report the feasibility of photothermal optical coherence tomography (PT-OCT) to image human mesenchymal stem cells (hMSCs) labeled with single-walled carbon nanotubes (SWNTs) for in vitro cell tracking in three dimensional scaffolds. PT-OCT is a functional extension of conventional OCT with extended capability of localized detection of absorbing targets from scattering background to provide depth-resolved molecular contrast imaging. A 91 kHz line rate, spectral domain PT-OCT system at 1310nm was developed to detect the photothermal signal generated by 800nm excitation laser. In general, MSCs do not have obvious optical absorption properties and cannot be directly visualized using PT-OCT imaging. However, the optical absorption properties of hMSCs can me modified by labeling with SWNTs. Using this approach, MSC were labeled with SWNT and the cell distribution imaged in a 3D polymer scaffold using PT-OCT.
3. Comparison of Atmospheric Column Optical Depth Measurements for Urban Reno, NV with Three Different Sun Photometers and In Situ Measurements Combined with Boundary Layer Height Estimation
Loria Salazar, S. M.; Arnott, W. P.; Moosmuller, H.; Sumlin, B.; Karr, D.
2011-12-01
Reno, Nevada, USA is located in a mountain valley often characterized by very dry conditions, clear sky and red sunsets during the summer season, with rare incursions of monsoonal moisture. This city is subject to moderately strong nocturnal inversions nearly every day in summer. Urban aerosols, wind blown dust, as well as occasional biomass burning smoke from natural and non-natural fires all contribute to the optical depth. Because of its geographical position, drastic changes in weather conditions and variations in aerosol optical properties make Reno an excellent location for evaluating measurements of aerosol optical depth in order to determine particulate air pollution concentration as well as to provide input for models of atmospheric radiation transfer and evaluation of satellite-based aerosol optical sensing measurements. Aerosol optical depth can be calculated by in situ photoacoustic measurements of aerosol light absorption and reciprocal nephelometer scattering coefficients and estimation of aerosol mixing height. LED-based hand-held sun photometers are commonly used as inexpensive instruments for informal networks. However, the LED emission wavelength maximum and bandwidth are higher and narrower than the LED reception wavelength spectrum, necessitating empirical determination of an equivalent wavelength. The manually operated spectrometer and Cimel sun photometer measurements provide the most accurate and precise column aerosol optical depth. This paper makes a comparison between these four instruments for measurements obtained during the summer and fall seasons in order to study how the total and aerosol optical depth change during dry and moist conditions. Ångström exponents of extinction and absorption are also analyzed to provide insight on aerosol size distribution and composition, respectively.
4. Study on the Relationship between the Depth of Spectral Absorption and the Content of the Mineral Composition of Biotite.
PubMed
Yang, Chang-bao; Zhang, Chen-xi; Liu, Fang; Jiang, Qi-gang
2015-09-01
The mineral composition of rock is one of the main factors affecting the spectral reflectance characteristics, and it's an important reason for generating various rock characteristic spectra. This study choose the rock samples provided by Jet Propulsion Laboratory (JPL) (including all kinds of mineral percentage of rocks, and spectral reflectances range from 0.35 to 2.50 μm wavelength measured by ASD spectrometer), and the various types of mineral spectral reflectances contained within the rocks are the essential data. Using the spectral linear mixture model of rocks and their minerals, firstly, a simulation study on the mixture of rock and mineral composition is achieved, the experimental results indicate that rock spectral curves using the model which based on the theory of the linear mixture are able to simulate better and preserve the absorption characteristics of various mineral components well. Then, 8 samples which contain biotite mineral are picked from the rock spectra of igneous, biotite contents and the absorption depth characteristics of spectral reflection at 2.332 μm, furthermore, a variety of linear and nonlinear normal statistical models are used to fit the relationship between the depth of absorption spectra and the content of the mineral composition of biotite, finally, a new simulation model is build up with the Growth and the Exponential curve model, and a statistical response relationship between the spectral absorption depth and the rock mineral contents is simulated by using the new model, the fitting results show that the correlation coefficient reaches 0.9984 and the standard deviation is 0.572, although the standard deviation using Growth and Exponential model is less than the two model combined with the new model fitting the standard deviation, the correlation coefficient of the new model had significantly increased, which suggesting that the, new model fitting effect is closer to the measured values of samples, it proves that the
5. Optical performance and metallic absorption in nanoplasmonic systems.
PubMed
Arnold, Matthew D; Blaber, Martin G
2009-03-01
Optical metrics relating to metallic absorption in representative plasmonic systems are surveyed, with a view to developing heuristics for optimizing performance over a range of applications. We use the real part of the permittivity as the independent variable; consider strengths of particle resonances, resolving power of planar lenses, and guiding lengths of planar waveguides; and compare nearly-free-electron metals including Al, Cu, Ag, Au, Li, Na, and K. Whilst the imaginary part of metal permittivity has a strong damping effect, field distribution is equally important and thus factors including geometry, real permittivity and frequency must be considered when selecting a metal. Al performs well at low permittivities (e.g. sphere resonances, superlenses) whereas Au & Ag only perform well at very negative permittivities (shell and rod resonances, LRSPP). The alkali metals perform well overall but present engineering challenges. PMID:19259225
6. Optical re-injection in cavity-enhanced absorption spectroscopy
PubMed Central
Leen, J. Brian; O’Keefe, Anthony
2014-01-01
Non-mode-matched cavity-enhanced absorption spectrometry (e.g., cavity ringdown spectroscopy and integrated cavity output spectroscopy) is commonly used for the ultrasensitive detection of trace gases. These techniques are attractive for their simplicity and robustness, but their performance may be limited by the reflection of light from the front mirror and the resulting low optical transmission. Although this low transmitted power can sometimes be overcome with higher power lasers and lower noise detectors (e.g., in the near-infrared), many regimes exist where the available light intensity or photodetector sensitivity limits instrument performance (e.g., in the mid-infrared). In this article, we describe a method of repeatedly re-injecting light reflected off the front mirror of the optical cavity to boost the cavity's circulating power and deliver more light to the photodetector and thus increase the signal-to-noise ratio of the absorption measurement. We model and experimentally demonstrate the method's performance using off-axis cavity ringdown spectroscopy (OA-CRDS) with a broadly tunable external cavity quantum cascade laser. The power coupled through the cavity to the detector is increased by a factor of 22.5. The cavity loss is measured with a precision of 2 × 10−10 cm−1/\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}$\\sqrt {{\\rm Hz;}}$\\end{document} Hz ; an increase of 12 times over the standard off-axis configuration without reinjection and comparable to the best reported sensitivities in the mid-infrared. Finally, the re-injected CRDS system is used to measure the spectrum of several volatile organic compounds, demonstrating the improved ability to resolve weakly absorbing spectroscopic features. PMID:25273701
7. Optical re-injection in cavity-enhanced absorption spectroscopy.
PubMed
Leen, J Brian; O'Keefe, Anthony
2014-09-01
Non-mode-matched cavity-enhanced absorption spectrometry (e.g., cavity ringdown spectroscopy and integrated cavity output spectroscopy) is commonly used for the ultrasensitive detection of trace gases. These techniques are attractive for their simplicity and robustness, but their performance may be limited by the reflection of light from the front mirror and the resulting low optical transmission. Although this low transmitted power can sometimes be overcome with higher power lasers and lower noise detectors (e.g., in the near-infrared), many regimes exist where the available light intensity or photodetector sensitivity limits instrument performance (e.g., in the mid-infrared). In this article, we describe a method of repeatedly re-injecting light reflected off the front mirror of the optical cavity to boost the cavity's circulating power and deliver more light to the photodetector and thus increase the signal-to-noise ratio of the absorption measurement. We model and experimentally demonstrate the method's performance using off-axis cavity ringdown spectroscopy (OA-CRDS) with a broadly tunable external cavity quantum cascade laser. The power coupled through the cavity to the detector is increased by a factor of 22.5. The cavity loss is measured with a precision of 2 × 10(-10) cm(-1)/√Hz; an increase of 12 times over the standard off-axis configuration without reinjection and comparable to the best reported sensitivities in the mid-infrared. Finally, the re-injected CRDS system is used to measure the spectrum of several volatile organic compounds, demonstrating the improved ability to resolve weakly absorbing spectroscopic features. PMID:25273701
8. Optical re-injection in cavity-enhanced absorption spectroscopy
SciTech Connect
Leen, J. Brian O’Keefe, Anthony
2014-09-15
Non-mode-matched cavity-enhanced absorption spectrometry (e.g., cavity ringdown spectroscopy and integrated cavity output spectroscopy) is commonly used for the ultrasensitive detection of trace gases. These techniques are attractive for their simplicity and robustness, but their performance may be limited by the reflection of light from the front mirror and the resulting low optical transmission. Although this low transmitted power can sometimes be overcome with higher power lasers and lower noise detectors (e.g., in the near-infrared), many regimes exist where the available light intensity or photodetector sensitivity limits instrument performance (e.g., in the mid-infrared). In this article, we describe a method of repeatedly re-injecting light reflected off the front mirror of the optical cavity to boost the cavity's circulating power and deliver more light to the photodetector and thus increase the signal-to-noise ratio of the absorption measurement. We model and experimentally demonstrate the method's performance using off-axis cavity ringdown spectroscopy (OA-CRDS) with a broadly tunable external cavity quantum cascade laser. The power coupled through the cavity to the detector is increased by a factor of 22.5. The cavity loss is measured with a precision of 2 × 10{sup −10} cm{sup −1}/√(Hz;) an increase of 12 times over the standard off-axis configuration without reinjection and comparable to the best reported sensitivities in the mid-infrared. Finally, the re-injected CRDS system is used to measure the spectrum of several volatile organic compounds, demonstrating the improved ability to resolve weakly absorbing spectroscopic features.
9. Excitonic Effects and Optical Absorption Spectrum of Doped Graphene
Jornada, Felipe; Deslippe, Jack; Louie, Steven
2012-02-01
First-principles calculations based on the GW-Bethe-Salpeter Equation (GW-BSE) approach and subsequent experiments have shown large excitonic effects in the optical absorbance of graphene. Here we employ the GW-BSE formalism to probe the effects of charge carrier doping and of having an external electric field on the absorption spectrum of graphene. We show that the absorbance peak due to the resonant exciton exhibits systematic changes in both its position and profile when graphene is gate doped by carriers, in excellent agreement to very recent measurementsootnotetextTony F. Heinz, private communications.. We analyze the various contributions to these changes in the absorption spectrum, such as the effects of screening by carriers to the quasiparticle energies and electron-hole interactions. This work was supported by National Science Foundation Grant No. DMR10-1006184, the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, and the U.S. DOD - Office of Naval Research under RTC Grant No. N00014-09-1-1066. Computer time was provided by NERSC.
10. Absorption Filter Based Optical Diagnostics in High Speed Flows
NASA Technical Reports Server (NTRS)
Samimy, Mo; Elliott, Gregory; Arnette, Stephen
1996-01-01
Two major regimes where laser light scattered by molecules or particles in a flow contains significant information about the flow are Mie scattering and Rayleigh scattering. Mie scattering is used to obtain only velocity information, while Rayleigh scattering can be used to measure both the velocity and the thermodynamic properties of the flow. Now, recently introduced (1990, 1991) absorption filter based diagnostic techniques have started a new era in flow visualization, simultaneous velocity and thermodynamic measurements, and planar velocity measurements. Using a filtered planar velocimetry (FPV) technique, we have modified the optically thick iodine filter profile of Miles, et al., and used it in the pressure-broaden regime which accommodates measurements in a wide range of velocity applications. Measuring velocity and thermodynamic properties simultaneously, using absorption filtered based Rayleigh scattering, involves not only the measurement of the Doppler shift, but also the spectral profile of the Rayleigh scattering signal. Using multiple observation angles, simultaneous measurement of one component velocity and thermodynamic properties in a supersonic jet were measured. Presently, the technique is being extended for simultaneous measurements of all three components of velocity and thermodynamic properties.
11. Measurement of optical penetration depth and refractive index of human tissue
Xie, Shusen; Li, Hui; Li, Buhong
2003-01-01
Experimental techniques for measurement of optical penetration depth and refractive index of human tissue are presented, respectively. Optical penetration depth can be obtained from the measurement of the relative fluence-depth distribution inside the target tissue. The depth of normal and carcinomatous human lung tissues irradiated with the wavelengths of 406.7, 632.8 and 674.4 nm in vitro are respectively determined. In addition, a novel simple method based on total internal reflection for measuring the refractive index of biotissue in vivo is developed, and the refractive indices of skin from people of different age, sex and skin color are measured. Their refractive indices are almost same and the average is 1.533.
12. VizieR Online Data Catalog: Perseus dust optical depth and column density maps (Zari+, 2016)
Zari, E.; Lombardi, M.; Alves, J.; Lada, C.; Bouy, H.
2015-11-01
We present optical depth and temperature maps of the Perseus Molecular Cloud, created combining Planck and Herschel data. The maps were obtained using Herschel SPIRE 250um, SPIRE 350um, SPIRE 500um, and, where available, PACS 160um data. The file planckherschelfit.fits reports the results of a full SED fit (with free parameters the optical depth and the temperature), at the SPIRE 500um resolution (36-arcsec). The file planckherschelfit2-a.fits uses the temperature from planckherschelfit.fits and the flux at SPIRE 250um to infer the optical depth with a resolution of 18 arcsec. Finally, the catalogue of Class I/0 protostars reports WISE magnitudes for the sources used to estimate the Schmidt law. (3 data files).
13. Constraining the CMB optical depth through the dispersion measure of cosmological radio transients
Fialkov, A.; Loeb, A.
2016-05-01
The dispersion measure of extragalactic radio transients can be used to measure the column density of free electrons in the intergalactic medium. The same electrons also scatter the Cosmic Microwave Background (CMB) photons, affecting precision measurements of cosmological parameters. We explore the connection between the dispersion measure of radio transients existing during the Epoch of Reionization (EoR) and the total optical depth for the CMB showing that the existence of such transients would provide a new sensitive probe of the CMB optical depth. As an example, we consider the population of FRBs. Assuming they exist during the EoR, we show that: (i) such sources can probe the reionization history by measuring the optical depth to sub-percent accuracy, and (ii) they can be detected with high significance by an instrument such as the Square Kilometer Array.
14. 3D Radiative Aspects of the Increased Aerosol Optical Depth Near Clouds
NASA Technical Reports Server (NTRS)
Marshak, Alexander; Wen, Guoyong; Remer, Lorraine; Cahalan, Robert; Coakley, Jim
2007-01-01
To characterize aerosol-cloud interactions it is important to correctly retrieve aerosol optical depth in the vicinity of clouds. It is well reported in the literature that aerosol optical depth increases with cloud cover. Part of the increase comes from real physics as humidification; another part, however, comes from 3D cloud effects in the remote sensing retrievals. In many cases it is hard to say whether the retrieved increased values of aerosol optical depth are remote sensing artifacts or real. In the presentation, we will discuss how the 3D cloud affects can be mitigated. We will demonstrate a simple model that can assess the enhanced illumination of cloud-free columns in the vicinity of clouds. This model is based on the assumption that the enhancement in the cloud-free column radiance comes from the enhanced Rayleigh scattering due to presence of surrounding clouds. A stochastic cloud model of broken cloudiness is used to simulate the upward flux.
15. Transmission and division of total optical depth method: A universal calibration method for Sun photometric measurements
Zhang, Ming; Gong, Wei; Ma, Yingying; Wang, Lunche; Chen, Zhongyong
2016-03-01
Sun photometric measurements, which provide accurate and timely information on atmospheric components such as aerosols, clouds, and gases are important to climate research. For regions with heavy and variable aerosol loading, the traditional Langley plot method cannot be applied for Sun photometric instrument calibration, as almost no suitable prolonged periods with stable atmosphere and low-aerosol loading occurs. An improved calibration method, namely, the transmission and division of total optical depth method, is proposed in this study. Atmospheric total optical depth variation information obtained via other methods is transmitted, and period groups with similar atmospheric extinction effects are selected for Langley regression. This method is validated through calibration of a multifilter rotating shadowband radiometer under heavy aerosol-loading conditions. The obtained aerosol optical depth (AOD) compares well with the interpolated AOD from a Cimel Sun-sky radiometer.
16. Depth enhancement in spectral domain optical coherence tomography using bidirectional imaging modality with a single spectrometer
Ravichandran, Naresh Kumar; Wijesinghe, Ruchire Eranga; Shirazi, Muhammad Faizan; Park, Kibeom; Jeon, Mansik; Jung, Woonggyu; Kim, Jeehyun
2016-07-01
A method for depth enhancement is presented using a bidirectional imaging modality for spectral domain optical coherence tomography (SD-OCT). Two precisely aligned sample arms along with two reference arms were utilized in the optical configuration to scan the samples. Using exemplary images of the optical resolution target, Scotch tape, a silicon sheet with two needles, and a leaf, we demonstrated how the developed bidirectional SD-OCT imaging method increases the ability to characterize depth-enhanced images. The results of the developed system were validated by comparing the images with the standard OCT configuration (single-sample arm setup). Given the advantages of higher resolution and the ability to visualize deep morphological structures, this method can be utilized to increase the depth dependent fall-off in samples with limited thickness. Thus, the proposed bidirectional imaging modality is apt for cross-sectional imaging of entire samples, which has the potential capability to improve the diagnostic ability.
17. Quantitative comparison of wavelength dependence on penetration depth and imaging contrast for ultrahigh-resolution optical coherence tomography using supercontinuum sources at five wavelength regions
Ishida, S.; Nishizawa, N.
2012-01-01
Optical coherence tomography (OCT) is a non invasive optical imaging technology for micron-scale cross-sectional imaging of biological tissue and materials. We have been investigating ultrahigh resolution optical coherence tomography (UHR-OCT) using fiber based supercontinuum sources. Although ultrahigh longitudinal resolution was achieved in several center wavelength regions, its low penetration depth is a serious limitation for other applications. To realize ultrahigh resolution and deep penetration depth simultaneously, it is necessary to choose the proper wavelength to maximize the light penetration and enhance the image contrast at deeper depths. Recently, we have demonstrated the wavelength dependence of penetration depth and imaging contrast for ultrahigh resolution OCT at 0.8 μm, 1.3 μm, and 1.7 μm wavelength ranges. In this paper, additionally we used SC sources at 1.06 μm and 1.55 μm, and we have investigated the wavelength dependence of UHR-OCT at five wavelength regions. The image contrast and penetration depth have been discussed in terms of the scattering coefficient and water absorption of samples. Almost the same optical characteristics in longitudinal and lateral resolution, sensitivity, and incident optical power at all wavelength regions were demonstrated. We confirmed the enhancement of image contrast and decreased ambiguity of deeper epithelioid structure at longer wavelength region.
18. Increasing the penetration depth for ultrafast laser tissue ablation using glycerol based optical clearing
Gabay, Ilan; Subramanian, Kaushik G.; Martin, Chris; Yildirim, Murat; Tuchin, Valery V.; Ben-Yakar, Adela
2016-03-01
Background: Deep tissue ablation is the next challenge in ultrafast laser microsurgery. By focusing ultrafast pulses below the tissue surface one can create an ablation void confined to the focal volume. However, as the ablation depth increases in a scattering tissue, increase in the required power can trigger undesired nonlinear phenomena out of focus that restricts our ability to ablate beyond a maximum ablation depth of few scattering lengths. Optical clearing (OC) might reduce the intensity and increase the maximal ablation depth by lowering the refractive index mismatch, and therefore reducing scattering. Some efforts to ablate deeper showed out of focus damage, while others used brutal mechanical methods for clearing. Our clinical goal is to create voids in the scarred vocal folds and inject a biomaterial to bring back the tissue elasticity and restore phonation. Materials and methods: Fresh porcine vocal folds were excised and applied a biocompatible OC agent (75% glycerol). Collimated transmittance was monitored. The tissue was optically cleared and put under the microscope for ablation threshold measurements at different depths. Results: The time after which the tissue was optically cleared was roughly two hours. Fitting the threshold measurements to an exponential decay graph indicated that the scattering length of the tissue increased to 83+/-16 μm, which is more than doubling the known scattering length for normal tissue. Conclusion: Optical clearing with Glycerol increases the tissue scattering length and therefore reduces the energy for ablation and increases the maximal ablation depth. This technique can potentially improve clinical microsurgery.
19. Measurements of total column ozone, precipitable water content and aerosol optical depth at Sofia
Kaleyna, P.; Kolev, N.; Savov, P.; Evgenieva, Ts.; Danchovski, V.; Muhtarov, P.
2016-03-01
This article reports the results of a study related to variations in total ozone content, aerosol optical depth, water vapor content and Ångström coefficients from summer campaign carried out in June-July 2014, at two sites in the city of Sofia (Astronomical Observatory in the Borisova Gradina Park and National Institute of Geophysics, Geodesy and Geography (NIGGG)). The results of data analysis indicate the following: Spectral dependence of aerosol optical depth (AOD); Greater AOD values due to greater portion of aerosols; Inverse relationship between the time variations of AOD or water vapor and ozone.
20. 24 mm depth range discretely swept optical frequency domain imaging in dentistry
Kakuma, Hideo; Choi, DongHak; Furukawa, Hiroyuki; Hiro-Oka, Hideaki; Ohbayashi, Kohji
2009-02-01
A large depth range is needed if optical coherence tomography (OCT) is to be used to observe multiple teeth simultaneously. A discretely swept optical frequency domain imaging system with a 24-mm depth range was made by using a superstructure-grating distributed Bragg reflector (SSG-DBR) laser as the light source and setting the frequencystep interval to be 3.13 GHz (λ ~ 0.026 nm). The swept wavelength range was 40 nm centered at 1580 nm, the resolution was 29 μm, and the A-scan rate was 1.3 kHz. Application of the OCT system to a dental phantom was demonstrated.
1. A disposable flexible skin patch for clinical optical perfusion monitoring at multiple depths
Farkas, Dana L.; Kolodziejski, Noah J.; Stapels, Christopher J.; McAdams, Daniel R.; Fernandez, Daniel E.; Podolsky, Matthew J.; Christian, James F.; Ward, Brent B.; Vartarian, Mark; Feinberg, Stephen E.; Lee, Seung Yup; Parikh, Urmi; Mycek, Mary-Ann; Joyner, Michael J.; Johnson, Christopher P.; Paradis, Norman A.
2016-03-01
Stable, relative localization of source and detection fibers is necessary for clinical implementation of quantitative optical perfusion monitoring methods such as diffuse correlation spectroscopy (DCS) and diffuse reflectance spectroscopy (DRS). A flexible and compact device design is presented as a platform for simultaneous monitoring of perfusion at a range of depths, enabled by precise location of optical fibers in a robust and secure adhesive patch. We will discuss preliminary data collected on human subjects in a lower body negative pressure model for hypovolemic shock. These data indicate that this method facilitates simple and stable simultaneous monitoring of perfusion at multiple depths and within multiple physiological compartments.
2. Trace gas emissions from biomass burning inferred from aerosol optical depth
Paton-Walsh, Clare; Jones, Nicholas; Wilson, Stephen; Meier, Arndt; Deutscher, Nicholas; Griffith, David; Mitchell, Ross; Campbell, Susan
2004-03-01
We have observed strong correlations between simultaneous and co-located measurements of aerosol optical depth and column amounts of carbon monoxide, hydrogen cyanide, formaldehyde and ammonia in bushfire smoke plumes over SE Australia during the Austral summers of 2001/2002 and 2002/2003. We show how satellite-derived aerosol optical depth maps may be used in conjunction with these correlations to determine the total amounts of these gases present in a fire-affected region. This provides the basis of a method for estimating total emissions of trace gases from biomass burning episodes using visible radiances measured by satellites.
3. Analytical Derivation of the Vegetation Optical Depth from the Microwave Polarization Difference Index
NASA Technical Reports Server (NTRS)
Meesters, Antoon G. C. A.; DeJeu, Richard A. M.; Owe, Manfred
2006-01-01
A numerical solution for the canopy optical depth in an existing microwave-based land surface parameter retrieval model is presented. The optical depth is derived from the microwave polarization difference index and the dielectric constant of the soil. The original procedure used an approximation in the form of a logarithmic decay function to define this relationship, and was derived through a series of lengthy polynomials. These polynomials had to be recalculated when the scattering albedo or antenna incidence angle changes. The new procedure is computationally more efficient and accurate.
4. Design and fabrication of an optical probe with a phase filter for extended depth of focus.
PubMed
Xing, Jingchao; Kim, Junyoung; Yoo, Hongki
2016-01-25
The trade-off between spot size and depth of focus (DOF) often limits the performance of optical systems, such as optical coherence tomography and optical tweezers. Although researchers have proposed various methods to extend the DOF in free-space optics, many are difficult to implement in miniaturized optical probes due to space limitations. In this study, we present an optical probe with an extended DOF using a binary phase spatial filter (BPSF). The BPSF pattern was fabricated on the distal tip of an optical probe with a diameter of 1 mm by replica molding soft lithography, which can be easily implemented in a miniaturized optical probe due to its simple configuration. We optimized the BPSF pattern to enhance DOF, spot diameter, and light efficiency. To evaluate the fabricated endoscopic optical probe, we measured the three-dimensional point spread function of the BPSF probe and compared it with a probe without BPSF. The BPSF probe has a spot diameter of 3.56 μm and a DOF of 199.7 μm, while the probe without BPSF has a spot diameter of 3.69 μm and a DOF of 73.9 μm, representing a DOF gain of 2.7. We anticipate that this optical probe can be used in biomedical applications, including optical imaging and optical trapping techniques. PMID:26832486
5. Average depth of blood vessels in skin and lesions deduced by optical fiber spectroscopy
Jacques, Steven L.; Saidi, Iyad S.; Tittel, Frank K.
1994-09-01
The average depth of blood vessels in a cutaneous site, either normal or diseased, can be specified by a simple rapid noninvasive optical measurement. An optical fiber spectrophotometer delivers white light via optical fibers to a skin site. The light reflected by tissue scattering and successfully collected by optical fibers is carried to a diode array spectrophotometer for spectral analysis. The reflectance spectrum is analyzed to specify the component of the optical density (OD) spectrum which is attributed to the cutaneous blood. Then the ratio of the OD420 nm/OD585 nm provides a quantitative indication of the average depth of the blood in the skin site. The purple light (420 nm) less easily penetrates the skin to sample the cutaneous blood content than does the yellow light (585 nm). The calibration of the measurement was accomplished by Monte Carlo simulations of measurements on skin with a layer of blood at various depths. In a study of 47 neonates, the amount of blood content ranged from 4 - 12 mg hemoglobin/g tissue (equivalent to 0.8 - 2.4% of the skin volume being whole blood), and the average depth of blood ranged from 250 - 425 micrometers .
6. Remote sensing of atmospheric optical depth using a smartphone sun photometer.
PubMed
Cao, Tingting; Thompson, Jonathan E
2014-01-01
In recent years, smart phones have been explored for making a variety of mobile measurements. Smart phones feature many advanced sensors such as cameras, GPS capability, and accelerometers within a handheld device that is portable, inexpensive, and consistently located with an end user. In this work, a smartphone was used as a sun photometer for the remote sensing of atmospheric optical depth. The top-of-the-atmosphere (TOA) irradiance was estimated through the construction of Langley plots on days when the sky was cloudless and clear. Changes in optical depth were monitored on a different day when clouds intermittently blocked the sun. The device demonstrated a measurement precision of 1.2% relative standard deviation for replicate photograph measurements (38 trials, 134 datum). However, when the accuracy of the method was assessed through using optical filters of known transmittance, a more substantial uncertainty was apparent in the data. Roughly 95% of replicate smart phone measured transmittances are expected to lie within ±11.6% of the true transmittance value. This uncertainty in transmission corresponds to an optical depth of approx. ±0.12-0.13 suggesting the smartphone sun photometer would be useful only in polluted areas that experience significant optical depths. The device can be used as a tool in the classroom to present how aerosols and gases effect atmospheric transmission. If improvements in measurement precision can be achieved, future work may allow monitoring networks to be developed in which citizen scientists submit acquired data from a variety of locations. PMID:24416199
7. Calculation of optical properties of dental composites as a basis for determining color impression and penetration depth of laser light
Weniger, Kirsten K.; Muller, Gerhard J.
2005-03-01
In order to achieve esthetic dental restorations, there should be no visible difference between restorative material and treated teeth. This requires a match of the optical properties of both restorative material and natural teeth. These optical properties are determined by absorption and scattering of light emerging not only on the surface but also inside the material. Investigating different dental composites in several shades, a method has been developed to calculate the optical parameters absorption coefficient μa, scattering coefficient μs, anisotropy factor g and reduced scattering coefficient μs'. The method includes sample preparation and measurements of transmittance and reflectance in an integrating sphere spectrometer, followed by inverse Monte Carlo simulations. Determination of optical properties is more precise and comprehensive than with the previously used Kubelka Munk theory because scattering can be looked at separated into pure scattering with the scattering coefficient μs and its direction with the anisotropy factor g. Moreover the use of the inverse Monte Carlo simulation not only minimizes systematic errors and considers the scattering phase function, but also takes into account the measuring geometry. The compilation of a data pool of optical parameters now enables the application of further calculation models as a basis for optimization of the composition of new materials. For example, a prediction of the general color impression for multiple layers can be carried out as well as the calculation of the wavelength dependent penetration depths of light with regard to photo polymerization. Further applications are possible in the area of laser ablation.
8. Performance of reduced bit-depth acquisition for optical frequency domain imaging
PubMed Central
Goldberg, Brian D.; Vakoc, Benjamin J.; Oh, Wang-Yuhl; Suter, Melissa J.; Waxman, Sergio; Freilich, Mark I.; Bouma, Brett E.; Tearney, Guillermo J.
2009-01-01
High-speed optical frequency domain imaging (OFDI) has enabled practical wide-field microscopic imaging in the biological laboratory and clinical medicine. The imaging speed of OFDI, and therefore the field of view, of current systems is limited by the rate at which data can be digitized and archived rather than the system sensitivity or laser performance. One solution to this bottleneck is to natively digitize OFDI signals at reduced bit depths, e.g., at 8-bit depth rather than the conventional 12–14 bit depth, thereby reducing overall bandwidth. However, the implications of reduced bit-depth acquisition on image quality have not been studied. In this paper, we use simulations and empirical studies to evaluate the effects of reduced depth acquisition on OFDI image quality. We show that image acquisition at 8-bit depth allows high system sensitivity with only a minimal drop in the signal-to-noise ratio compared to higher bit-depth systems. Images of a human coronary artery acquired in vivo at 8-bit depth are presented and compared with images at higher bit-depth acquisition. PMID:19770914
9. Aerosol optical Depth Measurements in the UVB and visible at Ispra, Italy: 1992 TO 2002
Gröbner, J.; Meleti, C.
2003-04-01
Since 1992 direct solar irradiance has been measured with a Brewer spectroradiometer typ MKIV at several wavelengths in the UVB (between 306 and 320 nm) and visible (between 431 and 453 nm) part of the solar spectrum. So far, the measurements in the UVB were only used to determine the total column Ozone while those in the visible were used for the total column Nitrogen Dioxide. Here we present a re-evaluation of the whole times series with respect to aerosol optical depth (aod) using the same direct solar irradiance measurements. AOD measurements since 1997 from a CIMEL spectrophotometer belonging to AERONET were used as a cross check to verify the quality of the retrieved Brewer data. In the UVB, the calibration is based on routine lamp measurements performed on the global irradiance port of the Brewer and then transferred to the direct irradiance port using a custom measurement procedure. The calibration in the visible is based on Langley-plots performed at Ispra. A second method to calculate the relative extraterrestrials constants (ETC) for the Brewer using CIMEL data was also applied. The estimated ETC of the two methods agree to better than 4.5%. Comparison between the aod as derived from the Brewer spectroradiometer and the aod at 440 nm from the CIMEL instrument shows that the data are strongly correlated, confirming that the Brewer direct sun measurements are able to provide reliable aod. A detailed study reveals that the NO2 absorption needs to be taken into account for more accurate aod estimations in these wavelength regions. Finally, the time series of the Å ngström exponent α calculated from the retrieved aod is presented and its performance discussed.
10. Design of an optical system with large depth of field using in the micro-assembly
Li, Rong; Chang, Jun; Zhang, Zhi-jing; Ye, Xin; Zheng, Hai-jing
2013-08-01
Micro system currently is the mainstream of application and demand of the field of micro fabrication of civilian and national defense. Compared with the macro assembly, the requirements on location accuracy of the micro-assembly system are much higher. Usually the dimensions of the components of the micro-assembly are mostly between a few microns to several hundred microns. The general assembly precision requires for the sub-micron level. Micro system assembly is the bottleneck of micro fabrication currently. The optical stereo microscope used in the field of micro assembly technology can achieve high-resolution imaging, but the depth of field of the optical imaging system is too small. Thus it's not conducive to the three-dimensional observation process of the micro-assembly. This paper summarizes the development of micro system assembly at home and abroad firstly. Based on the study of the core features of the technology, a program is proposed which uses wave front coding technology to increase the depth of field of the optical imaging system. In the wave front coding technology, by combining traditional optical design with digital image processing creatively, the depth of field can be greatly increased, moreover, all defocus-related aberrations, such as spherical aberration, chromatic aberration, astigmatism, Ptzvel(field) curvature, distortion, and other defocus induced by the error of assembling and temperature change, can be corrected or minimized. In this paper, based on the study of theory, a set of optical microscopy imaging system is designed. This system is designed and optimized by optical design software CODE V and ZEMAX. At last, the imaging results of the traditional optical stereo microscope and the optical stereo microscope applied wave front coding technology are compared. The results show that: the method has a practical operability and the phase plate obtained by optimized has a good effect on improving the imaging quality and increasing the
11. Removing the depth-degeneracy in optical frequency domain imaging with frequency shifting
PubMed Central
Yun, S. H.; Tearney, G. J.; de Boer, J. F.; Bouma, B. E.
2009-01-01
A novel technique using an acousto-optic frequency shifter in optical frequency domain imaging (OFDI) is presented. The frequency shift eliminates the ambiguity between positive and negative differential delays, effectively doubling the interferometric ranging depth while avoiding image cross-talk. A signal processing algorithm is demonstrated to accommodate nonlinearity in the tuning slope of the wavelength-swept OFDI laser source. PMID:19484034
12. Study on distribution of aerosol optical depth in Chongqing urban area
Yang, Shiqi; Liu, Can; Gao, Yanghua
2015-12-01
This paper selected 6S (second simulation of the satellite signal in the solar spectrum) model with dark pixel method to inversion aerosol optical depth by MODIS data, and got the spatial distribution and the temporal distribution of Chongqing urban area. By comparing with the sun photometer and API data, the result showed that the inversion method can be used in aerosol optical thickness monitoring in Chongqing urban area.
13. Pulsed airborne lidar measurements of atmospheric optical depth using the Oxygen A-band at 765 nm
Riris, H.; Rodriguez, M.; Allan, G. R.; Mao, J.; Hasselbrack, W.; Abshire, J. B.
2013-12-01
We report on an airborne demonstration of atmospheric oxygen (O2) optical depth measurements with an Integrated Path Differential Absorption (IPDA) lidar using a fiber-based laser system and a photon counting detector. Accurate atmospheric temperature and pressure measurements are required for NASA's Active Sensing of CO2 Emissions over Nights, Days and Seasons (ASCENDS) space mission. Since O2 in uniformly mixed in the atmosphere, its absorption spectra can be used to estimate atmospheric pressure. In its airborne configuration, the IPDA lidar uses a doubled Erbium Doped Fiber amplifier and single photon counting detector to measure oxygen absorption at multiple discrete wavelengths in the oxygen A-band near 765 nm. This instrument has been deployed three times aboard NASA's DC-8 airborne laboratory as part of campaigns to measure CO2 mixing ratios over a wide range of topography and weather conditions from altitudes between 3 km and 13 km. The O2 IPDA lidar flew seven flights in 2011 and six flights in 2013 in the continental United States and British Columbia, Canada. Our results from 2011 showed good agreement between the experimentally derived differential optical depth measurements with the theoretical predictions for aircraft altitudes from 3 to 13 km after a systematic bias correction of approximately 8% was applied. The random noise component was 2.5-3.0 %. The most recent data recorded in 2013 show better agreement between experimental optical depth measurements and theoretical predictions and much smaller systematic errors. The random error remained comparable with 2011 at 2-3%. The main source of random error is primarily the low energy (power) of the laser transmitter and the high solar background. We are in the process of addressing this issue with a new, higher energy amplifier that we anticipate will reduce the random noise component by a factor of 3-5 to less than 0.5%. The results from these flights show that the IPDA technique is a viable method
14. Airborne imaging spectrometer data of the Ruby Mountains, Montana: Mineral discrimination using relative absorption band-depth images
USGS Publications Warehouse
Crowley, J.K.; Brickey, D.W.; Rowan, L.C.
1989-01-01
Airborne imaging spectrometer data collected in the near-infrared (1.2-2.4 ??m) wavelength range were used to study the spectral expression of metamorphic minerals and rocks in the Ruby Mountains of southwestern Montana. The data were analyzed by using a new data enhancement procedure-the construction of relative absorption band-depth (RBD) images. RBD images, like bandratio images, are designed to detect diagnostic mineral absorption features, while minimizing reflectance variations related to topographic slope and albedo differences. To produce an RBD image, several data channels near an absorption band shoulder are summed and then divided by the sum of several channels located near the band minimum. RBD images are both highly specific and sensitive to the presence of particular mineral absorption features. Further, the technique does not distort or subdue spectral features as sometimes occurs when using other data normalization methods. By using RBD images, a number of rock and soil units were distinguished in the Ruby Mountains including weathered quartz - feldspar pegmatites, marbles of several compositions, and soils developed over poorly exposed mica schists. The RBD technique is especially well suited for detecting weak near-infrared spectral features produced by soils, which may permit improved mapping of subtle lithologic and structural details in semiarid terrains. The observation of soils rich in talc, an important industrial commodity in the study area, also indicates that RBD images may be useful for mineral exploration. ?? 1989.
15. Optical Absorption Microspectroscopy (μ-OAS) Based on Schwarzschild-Type Cassegrain Optics.
PubMed
Chassé, Mathieu; Lelong, Gérald; van Nijnatten, Peter; Schoofs, Ivo; de Wolf, Jürgen; Galoisy, Laurence; Calas, Georges
2015-04-01
A new experimental setup, combining a custom-designed Schwarzschild-type Cassegrain-based microscope and an ultraviolet-visible-near infrared (UV-Vis-NIR) spectrophotometer, has been developed, focusing the light beam down to 20 μm diameter. Optical absorption spectra (in the 300-2500 nm range) have been measured on micrometer-sized natural glass inclusions providing information on iron speciation in magmatic melts. The absence of contribution from the host crystal matrix provides a test of the efficiency of micro-focusing. A microthermometric stage has been adapted on the microscope for measuring optical absorption spectra up to 900 K with application to the thermochromism of minute natural spinel crystals (MgAl2O4:Fe(2+),Cr(3+)). This experimental setup provides an easy and fast way to follow the evolution of spectral properties and color of glasses or crystals with temperature as well as the possibility of measuring spatially resolved optical absorption spectra. PMID:25741926
16. Lidar multiple scattering factors inferred from CALIPSO lidar and IIR retrievals of semi-transparent cirrus cloud optical depths over oceans
Garnier, A.; Pelon, J.; Vaughan, M. A.; Winker, D. M.; Trepte, C. R.; Dubuisson, P.
2015-07-01
Cirrus cloud absorption optical depths retrieved at 12.05 μm are compared to extinction optical depths retrieved at 0.532 μm from perfectly co-located observations of single-layered semi-transparent cirrus over ocean made by the Imaging Infrared Radiometer (IIR) and the Cloud and Aerosol Lidar with Orthogonal Polarization (CALIOP) flying on board the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) satellite. IIR infrared absorption optical depths are compared to CALIOP visible extinction optical depths when the latter can be directly derived from the measured apparent two-way transmittance through the cloud. An evaluation of the CALIOP multiple scattering factor is inferred from these comparisons after assessing and correcting biases in IIR and CALIOP optical depths reported in version 3 data products. In particular, the blackbody radiance taken in the IIR version 3 algorithm is evaluated, and IIR retrievals are corrected accordingly. Numerical simulations and IIR retrievals of ice crystal sizes suggest that the ratios of CALIOP extinction and IIR absorption optical depths should remain roughly constant with respect to temperature. Instead, these ratios are found to increase quasi-linearly by about 40 % as the temperature at the layer centroid altitude decreases from 240 to 200 K. It is discussed that this behavior can be explained by variations of the multiple scattering factor ηT applied to correct the measured apparent two-way transmittance for contribution of forward-scattering. While the CALIOP version 3 retrievals hold ηT fixed at 0.6, this study shows that ηT varies with temperature (and hence cloud particle size) from ηT = 0.8 at 200 K to ηT = 0.5 at 240 K for single-layered semi-transparent cirrus clouds with optical depth larger than 0.3. The revised parameterization of ηT introduces a concomitant temperature dependence in the simultaneously derived CALIOP lidar ratios that is consistent with observed changes in CALIOP
17. In-vivo measurements of penetration depth, oxygenation, and drug concentration using broadband absorption spectroscopy in human tissues before and after photodynamic therapy
Wang, Hsing-Wen; Zhu, Timothy C.; Solonenko, Michael; Hahn, Stephen M.; Metz, James M.; Dimofte, Andrea; Mile, Jermy; Yodh, Arjun G.
2003-06-01
Photodynamic therapy (PDT) employs a combination of photosensitizing chemical, light, and oxygen Knowledge of tissue optical properties, including absorption (μa) and reduce scattering coefficients (μs"), makes possible to derive blood oxygen saturation, light penetration depth, and drug concentration, which are important to ensure PDT treatment efficacy at the specific wavelengths. We have developed an absorption spectroscopy system to measure μa and μs" in the spectral range 600-800nm using a contact linear probe with a source fiber and multiple source-detector separation distances less than 1 cm. The μa and μs" were recovered based on diffusion approximations of the photon transport equation. We measured tissue optical properties among various organs of patients with intraperitoneal malignancies for an on-going Phase II PDT protocol. The results from 12 patients showed various effective penetration depth from site to site and from organ to organ. The percentage oxygen saturation (%StO2) are similar before and after PDT. Before PDT, meff (mean (standard deviation) (number of patients)) in cm-1 at 630nm are 2.4 (0.2) (12) in small bowel, 2.2(0.4) (9) in large bowel, 4.2(2.7) (7) in tumor, 3.3 (0.3) (10) in peritoneum, 2.7 (0.3) (11) in skin, and 10.1 (0.6) (10) in liver. %StO2 is 60-80% for most organs but 30-40% for tumor.
18. Analysis of airborne imaging spectrometer data for the Ruby Mountains, Montana, by use of absorption-band-depth images
NASA Technical Reports Server (NTRS)
Brickey, David W.; Crowley, James K.; Rowan, Lawrence C.
1987-01-01
Airborne Imaging Spectrometer-1 (AIS-1) data were obtained for an area of amphibolite grade metamorphic rocks that have moderate rangeland vegetation cover. Although rock exposures are sparse and patchy at this site, soils are visible through the vegetation and typically comprise 20 to 30 percent of the surface area. Channel averaged low band depth images for diagnostic soil rock absorption bands. Sets of three such images were combined to produce color composite band depth images. This relative simple approach did not require extensive calibration efforts and was effective for discerning a number of spectrally distinctive rocks and soils, including soils having high talc concentrations. The results show that the high spectral and spatial resolution of AIS-1 and future sensors hold considerable promise for mapping mineral variations in soil, even in moderately vegetated areas.
19. NEUTRAL HYDROGEN OPTICAL DEPTH NEAR STAR-FORMING GALAXIES AT z Almost-Equal-To 2.4 IN THE KECK BARYONIC STRUCTURE SURVEY
SciTech Connect
Rakic, Olivera; Schaye, Joop; Steidel, Charles C.; Rudie, Gwen C.
2012-06-01
We study the interface between galaxies and the intergalactic medium by measuring the absorption by neutral hydrogen in the vicinity of star-forming galaxies at z Almost-Equal-To 2.4. Our sample consists of 679 rest-frame UV-selected galaxies with spectroscopic redshifts that have impact parameters <2 (proper) Mpc to the line of sight of one of the 15 bright, background QSOs and that fall within the redshift range of its Ly{alpha} forest. We present the first two-dimensional maps of the absorption around galaxies, plotting the median Ly{alpha} pixel optical depth as a function of transverse and line-of-sight separation from galaxies. The Ly{alpha} optical depths are measured using an automatic algorithm that takes advantage of all available Lyman series lines. The median optical depth, and hence the median density of atomic hydrogen, drops by more than an order of magnitude around 100 kpc, which is similar to the virial radius of the halos thought to host the galaxies. The median remains enhanced, at the >3{sigma} level, out to at least 2.8 Mpc (i.e., >9 comoving Mpc), but the scatter at a given distance is large compared with the median excess optical depth, suggesting that the gas is clumpy. Within 100 (200) kpc, and over {+-}165 km s{sup -1}, the covering fraction of gas with Ly{alpha} optical depth greater than unity is 100{sup +0}{sub -32}% (66% {+-} 16%). Absorbers with {tau}{sub Ly{alpha}} > 0.1 are typically closer to galaxies than random. The mean galaxy overdensity around absorbers increases with the optical depth and also as the length scale over which the galaxy overdensity is evaluated is decreased. Absorbers with {tau}{sub Ly{alpha}} {approx} 1 reside in regions where the galaxy number density is close to the cosmic mean on scales {>=}0.25 Mpc. We clearly detect two types of redshift space anisotropies. On scales <200 km s{sup -1}, or <1 Mpc, the absorption is stronger along the line of sight than in the transverse direction. This 'finger of God
20. Parametric distortion of the optical absorption edge of a magnetic semiconductor by a strong laser field
SciTech Connect
Nunes, O.A.C.
1985-09-15
The influence of a strong laser field on the optical absorption edge of a direct-gap magnetic semiconductor is considered. It is shown that as the strong laser intensity increases the absorption coefficient is modified so as to give rise to an absorption tail below the free-field forbidden gap. An application is made for the case of the EuO.
1. INTEGRATING LIDAR AND SATELLITE OPTICAL DEPTH WITH AMBIENT MONITORING FOR 3-DIMENSIONAL PARTICULATE CHARACTERIZATION
EPA Science Inventory
A combination of in-situ PM2.5, sunphotometers, upward pointing lidar and satellite aerosol optical depth (AOD) instruments have been employed to better understand variability in the correlation between AOD and PM2.5 at the surface. Previous studies have shown good correlation be...
2. Empirical Relationship between particulate matter and Aerosol Optical Depth over Northern Tien-Shan, Central Asia
EPA Science Inventory
Measurements were obtained at two sites in northern Tien-Shan in Central Asia during a 1-year period beginning July 2008 to examine the statistical relationship between aerosol optical depth (AOD) and of fine [PM2.5, particles less than 2.5 μm aerodynamic diameter (AD)] and coars...
3. Relative skills of soil moisture and vegetation optical depth retrievals for agricultural drought monitoring
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Soil moisture condition is an important indicator for agricultural drought monitoring. Through the Land Parameter Retrieval Model (LPRM), vegetation optical depth (VOD) as well as surface soil moisture (SM) can be retrieved simultaneously from brightness temperature observations from the Advanced Mi...
4. Aerosol optical depth during episodes of Asian dust storms and biomass burning at Kwangju, South Korea
Ogunjobi, K. O.; He, Z.; Kim, K. W.; Kim, Y. J.
Spectral daily aerosol optical depths (τ a λ) estimated from a multi-filter radiometer over Kwangju were analyzed from January 1999 to August 2001 (total of 277 days). Optical depths obtained showed a pronounced temporal trend, with maximum dust loading observed during spring time and biomass burning aerosol in early summer and autumn of each year. Result indicates that τ a501 nm increased from spring average of 0.45±0.02 to values >0.7 on 7 April 2000, and 13 April 2001. Daily mean spectral variations in the Ångström exponents α were also computed for various episode periods under consideration. A dramatic change in α value is noted especially at high aerosol optical depth when coarse mode aerosol dominates over the influence of accumulation-mode aerosol. High values of τ a λ associated with high values of α in early June and October are characteristics of smoke aerosol predominantly from biomass burning aerosol. Also, volume size distribution is investigated for different pollution episodes with result indicating that the peak in the distribution of the coarse mode volume radius and fine mode particles of dust and biomass-burning aerosol respectively increases as aerosol optical depth increases at Kwangju. Air-mass trajectory were developed on 7-8 April and 19-20 October, 2000 to explain the transport of Asian dust particle and biomass burning to Kwangju.
5. Correction to “Hyperspectral Aerosol Optical Depths from TCAP Flights”
SciTech Connect
Shinozuka, Yohei; Johnson, Roy R.; Flynn, Connor J.; Russell, P. B.; Schmid, Beat; Redemann, Jens; Dunagan, Stephen; Kluzek, Celine D.; Hubbe, John M.; Segal-Rosenheimer, Michal; Livingston, J. M.; Eck, T.; Wagener, Richard; Gregory, L.; Chand, Duli; Berg, Larry K.; Rogers, Ray; Ferrare, R. A.; Hair, John; Hostetler, Chris A.; Burton, S. P.
2014-02-16
In the paper “Hyperspectral aerosol optical depths from TCAP flights” by Y. Shinozuka et al. (Journal of Geophysical Research: Atmospheres, 118, doi:10.1002/2013JD020596, 2013), Tables 1 and 2 were published with the column heads out of order. Tables 1 and 2 are published correctly here. The publisher regrets the error.
6. Direct numerical modeling of Saturn's dense rings at high optical depth
Richardson, Derek C.; Ballouz, Ronald-Louis; Morishima, Ryuji
2015-11-01
Saturn's B ring exhibits complex optical depth structure of uncertain origin. We are investigating the extent to which viscous overstability and/or gravitational wakes can give rise to this structure, via discrete particle numerical simulations. We use the parallelized N-body tree code pkdgrav with a soft-sphere collision model for detailed treatment of particle collisional physics, including multi-point persistent contact with static, sliding, rolling, and twisting friction forces. This enables us to perform local simulations with millions of particles, realistic sizes, and configurable material properties in high-optical-depth ring patches with near-linear scaling across multiple processors. Recent code improvements to the collision search algorithm provide a further roughly factor of 2 speedup. We present results from the first year of this study in which a library of simulations with different optical depths was constructed. Parameters explored include normal (dynamical) optical depths between 0.5 (approximately 100,000 particles) and 4.0 (approximately 8.3 million particles) in ring patches of dimension 6 by 6 critical Toomre wavelengths, using material parameters ranging from highly elastic smooth spheres to rough "gravel"-like particles. We also vary the particle internal densities to enhance (low density)/suppress (high density) viscous overstability in order to compare against gravitational instability in these different regimes. These libraries will be used to carry out simulated observations for comparison with Cassini CIRS temperature measurements and UVIS occulation data of Saturn's dense rings.
7. Ripeness of 'Sun Bright' tomato using the optical absorption and scattering properties
Technology Transfer Automated Retrieval System (TEKTRAN)
Maturity is one of the most important factors in determining the processing and eating quality of tomato. The objective of this research was to test the suitability of optical absorption and scattering properties for evaluating the maturity of tomatoes. Optical absorption and reduced scattering coef...
8. Continuous wavelet-transform analysis of photoacoustic signal waveform to determine optical absorption coefficient
Hirasawa, T.; Ishihara, M.; Tsujita, K.; Hirota, K.; Irisawa, K.; Kitagaki, M.; Fujita, M.; Kikuchi, M.
2012-02-01
In photo-acoustic (PA) imaging, valuable medical applications based on optical absorption spectrum such as contrast agent imaging and blood oxygen saturation measurement have been investigated. In these applications, there is an essential requirement to determine optical absorption coefficients accurately. In present, PA signal intensities have been commonly used to determine optical absorption coefficients. This method achieves practical accuracy by combining with radiative transfer analysis. However, time consumption of radiative transfer analysis and effects of signal generation efficiencies were problems of this method. In this research, we propose a new method to determine optical absorption coefficients using continuous wavelet transform (CWT). We used CWT to estimate instantaneous frequencies of PA signals which reflects optical absorption distribution. We validated the effectiveness of CWT in determination of optical absorption coefficients through an experiment. In the experiment, planar shaped samples were illuminated to generate PA signal. The PA signal was measured by our fabricated PA probe in which an optical fiber and a ring shaped P(VDFTrFE) ultrasound sensor were coaxially aligned. Optical properties of samples were adjusted by changing the concentration of dye solution. Tunable Ti:Sapphire laser (690 - 1000 nm) was used as illumination source. As a result, we confirmed strong correlation between optical absorption coefficients of samples and the instantaneous frequency of PA signal obtained by CWT. Advantages of this method were less interference of light transfer and signal generation efficiency.
9. Microlensing Optical Depth towards the Galactic Bulge Using Clump Giants from the MACHO Survey
SciTech Connect
Popowski, P; Griest, K; Thomas, C L; Cook, K H; Bennett, D P; Becker, A C; Alves, D R; Minniti, D; Drake, A J; Alcock, C; Allsman, R A; Axelrod, T S; Freeman, K C; Geha, M; Lehner, M J; Marshall, S L; Nelson, C A; Peterson, B A; Quinn, P J; Stubbs, C W; Sutherland, W; Vandehei, T; Welch, D
2005-07-14
Using 7 years of MACHO survey data, we present a new determination of the optical depth to microlensing towards the Galactic bulge. We select the sample of 62 microlensing events (60 unique) on clump giant sources and perform a detailed efficiency analysis. We use only the clump giant sources because these are bright bulge stars and are not as strongly affected by blending as other events. Using a subsample of 42 clump events concentrated in an area of 4.5 deg{sup 2} with 739000 clump giant stars, we find {tau} = 2.17{sub -0.38}{sup +0.47} x 10{sup -6} at (l,b) = (1{sup o}.50, -2{sup o}.68), somewhat smaller than found in most previous MACHO studies, but in excellent agreement with recent theoretical predictions. We also present the optical depth in each of the 19 fields in which we detected events, and find limits on optical depth for fields with no events. The errors in optical depth in individual fields are dominated by Poisson noise. We measure optical depth gradients of (1.06 {+-} 0.71) x 10{sup -6}deg{sup -1} and (0.29 {+-} 0.43) x 10{sup -6}deg{sup -1} in the galactic latitude b and longitude l directions, respectively. Finally, we discuss the possibility of anomalous duration distribution of events in the field 104 centered on (l,b) = (3{sup o}.11, -3{sup o}.01) as well as investigate spatial clustering of events in all fields.
10. The INTEGRAL/IBIS AGN catalogue - I. X-ray absorption properties versus optical classification | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6509696245193481, "perplexity": 4132.355370244775}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-44/segments/1476988718285.69/warc/CC-MAIN-20161020183838-00033-ip-10-171-6-4.ec2.internal.warc.gz"} |
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If $$x$$ and $$y$$ are positive integers, is $$x^{16} - y^8 + 345y^2$$ divisible by 15?
(1) $$x$$ is a multiple of 25, and $$y$$ is a multiple of 20
(2) $$y = x^2$$
[Reveal] Spoiler: OA
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First of all notice that since $$345y^2$$ is divisible by 15, we can drop it (this term won't affect the remainder).
The question becomes: is $$x^{16}-y^8$$ divisible by 15?
(1) $$x$$ is a multiple of 25, and $$y$$ is a multiple of 20. Now, both $$x$$ and $$y$$ could be multiples of 15 as well (eg $$x=25*15$$ and $$y=20*15$$) and in this case $$x^{16}-y^8=15*(...)$$ will be divisible by 15 OR one could be multiple of 15 and another not (e.g. $$x=25*15$$ and $$y=20$$) and in this case $$x^{16}-y^8$$ won't be divisible by 15 (as we cannot factor out 15 from $$x^{16}-y^8$$). Not sufficient.
(2) $$y = x^2$$. Substitute $$y$$ with $$x^2$$: $$x^{16}-y^8=x^{16}-(x^2)^8=x^{16}-x^{16}=0$$. 0 is divisible by 15 (zero is divisible by every integer except zero itself). Sufficient.
Notes for statement (1):
If integers $$a$$ and $$b$$ are both multiples of some integer $$k \gt 1$$ (divisible by $$k$$), then their sum and difference will also be a multiple of $$k$$ (divisible by $$k$$):
Example: $$a=6$$ and $$b=9$$, both divisible by 3: $$a+b=15$$ and $$a-b=-3$$, again both divisible by 3.
If out of integers $$a$$ and $$b$$ one is a multiple of some integer $$k \gt 1$$ and another is not, then their sum and difference will NOT be a multiple of $$k$$ (divisible by $$k$$):
Example: $$a=6$$, divisible by 3 and $$b=5$$, not divisible by 3: $$a+b=11$$ and $$a-b=1$$, neither is divisible by 3.
If integers $$a$$ and $$b$$ both are NOT multiples of some integer $$k \gt 1$$ (divisible by $$k$$), then their sum and difference may or may not be a multiple of $$k$$ (divisible by $$k$$):
Example: $$a=5$$ and $$b=4$$, neither is divisible by 3: $$a+b=9$$, is divisible by 3 and $$a-b=1$$, is not divisible by 3
OR: $$a=6$$ and $$b=3$$, neither is divisible by 5: $$a+b=9$$ and $$a-b=3$$, neither is divisible by 5
OR: $$a=2$$ and $$b=2$$, neither is divisible by 4: $$a+b=4$$ and $$a-b=0$$, both are divisible by 4.
So according to above info that $$x$$ is a multiple of 25, and $$y$$ is a multiple of 20 tells us nothing whether $$x^{16}-y^8$$ is divisible by 15.
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07 Jan 2015, 09:28
I think this question is good and helpful.
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10 Feb 2016, 05:55
I think this is a high-quality question and I agree with explanation.
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09 Mar 2016, 00:45
This is an Excellent Question
here is my approach
here in statement 1 => 1st is a non multiple of 15 and the rest two terms are
hence the result is a non multiple of 15 as we know that a multiple + non multiple is a non multiple.
statement 2 is sufficient as 345 is a multiple of 15 and rest two terms cancel out
So B
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23 May 2016, 18:08
Thanks for the question, got caught by it - was struggling with the (1) condition
stonecold:
stonecold wrote:
This is an Excellent Question
here is my approach
here in statement 1 => 1st is a non multiple of 15 and the rest two terms are
hence the result is a non multiple of 15 as we know that a multiple + non multiple is a non multiple.
statement 2 is sufficient as 345 is a multiple of 15 and rest two terms cancel out
So B
I quite not understand your reason for y^8 is divisible by 15 - the statement only says it's a multiple of 20 - could you explain a little bit more?
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09 Jan 2018, 22:24
I think the right answer is D.
x16−y8 has the x2+y as a factor which is 645 and divisible by 15 ==> D is correct.
x16−y8 = (x8+y4)(x8-y4)
(x8-y4)=(x4+y2)(x4-y2)
(x4-y2)=(x2+y)(x2-y)
you see my point?
Math Expert
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09 Jan 2018, 23:10
Java85 wrote:
I think the right answer is D.
x16−y8 has the x2+y as a factor which is 645 and divisible by 15 ==> D is correct.
x16−y8 = (x8+y4)(x8-y4)
(x8-y4)=(x4+y2)(x4-y2)
(x4-y2)=(x2+y)(x2-y)
you see my point?
You are not right. x is a multiple of 25, and y is a multiple of 20 does NOT mean that x^2 + y is a multiple of 645. You could check it VERY easily by picking some numbers: x = 25 any y = 40 --> x^2 + y = 665, which is NOT a multiple of 645. Please re-read the solution above carefully, it explains in detail (with examples) why the first statement is not sufficient.
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12 May 2018, 15:54
Hello Bunuel,
I approached this question using the remainder theorem. According to the theorem, the remainder of the expression [AxBxC]/M is the same as the remainder of expression [ArxBrxCr]/M (where Ar, Br, and Cr are the respective remainders when A, B, and C are divided by M. (For example, remainder of [16x19]/15 == remainder [1x3]/15 = 3).
Please let me know if you agree with this.
If so, then taking x=25 and y=40, we get :
Rem [(25^16 – 40^8)]/15
== [10^16 – 10^8]/15 (because 25/15 gives a remainder of 10, and 40/15 gives a remainder of 10)
= [100^8 – 10^8]/15 (rewriting 10^16 as 100^8 )
= [10^8 – 10^8]/15 (remainder of 100/15 = 10)
= 0
Therefore, if we take x=25, and y =40, the expression IS divisible by 15.
Similarly, I checked the value of expression $$x^16 - y^8$$ for different values of (x,y) such as (50,40), (25,20), (50,20), etc. and got the remainder to be 0.
Please let me know where am I going wrong.
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17 May 2018, 05:49
Hello Bunuel, or other experts, any thoughts on my post above?
Regards,
Paresh
Re: M02-02 [#permalink] 17 May 2018, 05:49
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1. # WorkshopHot Topics: Surface subgroups and cube complexes
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02:00 PM - 03:00 PM Surface quotients of hyperbolic buildings David Futer | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8805725574493408, "perplexity": 17645.66964227066}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-14/segments/1427131292567.7/warc/CC-MAIN-20150323172132-00132-ip-10-168-14-71.ec2.internal.warc.gz"} |
http://www.mathworks.com/help/matlab/ref/acosh.html?requestedDomain=www.mathworks.com&nocookie=true | # Documentation
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# acosh
Inverse hyperbolic cosine
## Syntax
Y = acosh(X)
## Description
Y = acosh(X) returns the inverse hyperbolic cosine for each element of X.
The acosh function operates element-wise on arrays. The function's domains and ranges include complex values. All angles are in radians.
## Examples
collapse all
Graph the inverse hyperbolic cosine function over the domain .
x = 1:pi/40:pi; plot(x,acosh(x)) grid on xlabel('x') ylabel('y')
collapse all
### Inverse Hyperbolic Cosine
For real values $x$ in the domain $x>1$, the inverse hyperbolic cosine satisfies
${\mathrm{cosh}}^{-1}\left(x\right)=\mathrm{log}\left(x+\sqrt{{x}^{2}-1}\right).$
For complex numbers $z=x+iy$, as well as real values in the domain $-\text{\hspace{0.17em}}\infty , the call acosh(z) returns complex results.
### Tall Array Support
This function fully supports tall arrays. For more information, see Tall Arrays. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 5, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8467317223548889, "perplexity": 7035.095619082609}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-44/segments/1476988719215.16/warc/CC-MAIN-20161020183839-00261-ip-10-171-6-4.ec2.internal.warc.gz"} |
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Question:
# A nerve impulse is transmitted through your nervous system primarily by ____.
A An electric potential
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Nerve impulses are transmitted in the nervous system primarily through the means of electric potentials, which are generated by a change in the balance of sodium, potassium, and calcium ions in the nerve cell.
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Great I gotta make a 50 or higher | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2508184611797333, "perplexity": 2573.2332532341024}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764500041.18/warc/CC-MAIN-20230202200542-20230202230542-00735.warc.gz"} |
https://worldwidescience.org/topicpages/n/nature+conservation+implications.html | #### Sample records for nature conservation implications
1. Shifting nature conservation approaches in Natura 2000 and the implications for the roles of stakeholders
NARCIS (Netherlands)
Ferranti, F.; Turnhout, E.; Beunen, R.; Behagel, J.H.
2014-01-01
This paper analyses Natura 2000 as a shifting configuration of different approaches to nature conservation and discusses the consequences of these shifts for the roles of the stakeholders affected by this policy. Natura 2000 started with a technocratic approach that privileged conservation experts a
2. Relationships, origin, and diversity of Galapagos tomatoes: implications for the conservation of natural populations.
Science.gov (United States)
Nuez, Fernando; Prohens, Jaume; Blanca, José M
2004-01-01
Endemic Galápagos tomatoes (Lycopersicon cheesmanii) are of great value for cultivated tomato (L. esculentum) breeding, and therefore their conservation is of significance. Although within L. cheesmanii there is heterogeneity for many traits and formal infraspecific classification is not justified, here we distinguish three forms, without taxonomic significance, of L. cheesmanii that are of interest to breeders because of their distinctive morphology and habitat preferences: L. cheesmanii 'short' (one- to two-pinnate leaves, short internodes, and coastal habitats), L. cheesmanii 'long' (one- to two-pinnate leaves, long internodes, and inland habitats), and L. cheesmanii forma minor (three- to four-pinnate leaves, short internodes, and coastal habitats). In a recent survey of tomato populations in the Galápagos Islands, we found that several populations of L. cheesmanii reported 30-50 years earlier had disappeared, mostly as a consequence of human activity. In addition, a previously unreported invasive wild red-fruited form, which we named L. esculentum 'Gal cer,' was found on the island of Santa Cruz. The total diversity (estimated with amplified fragment length polymorphisms [AFLPs]) within L. cheesmanii (H(T) = 0.051) is almost as high as that for the mainland wild species L. pimpinellifolium (H(T) = 0.072). Lycopersicon esculentum 'Gal cer,' on the other hand, has a much lower diversity (H(T) = 0.014). Comparison of AFLP fragments shared by L. esculentum 'Gal cer' with other species showed that it is closely related to weedy tomato L. esculentum var. cerasiforme and, therefore, likely of recent origin. Genetic differentiation among the three native L. cheesmanii forms is low (G(ST) = 0.235), indicating that they share a common genetic background. Nonetheless, L. cheesmanii 'short' is about twice as diverse as L. cheesmanii 'long' or L. cheesmanii f. minor. UPGMA cluster and principal components analysis distinguish four groups within Eulycopersicon: L
3. Deforestation and fragmentation of natural forests in the upper Changhua watershed, Hainan, China: implications for biodiversity conservation.
Science.gov (United States)
Zhai, De-Li; Cannon, Charles H; Dai, Zhi-Cong; Zhang, Cui-Ping; Xu, Jian-Chu
2015-01-01
Hainan, the largest tropical island in China, belongs to the Indo-Burma biodiversity hotspot. The Changhua watershed is a center of endemism for plants and birds and the cradle of Hainan's main rivers. However, this area has experienced recent and ongoing deforestation and habitat fragmentation. To quantify habitat loss and fragmentation of natural forests, as well as the land-cover changes in the Changhua watershed, we analyzed Landsat images obtained in 1988, 1995, and 2005. Land-cover dynamics analysis showed that natural forests increased in area (97,909 to 104,023 ha) from 1988 to 1995 but decreased rapidly to 76,306 ha over the next decade. Rubber plantations increased steadily throughout the study period while pulp plantations rapidly expanded after 1995. Similar patterns of land cover change were observed in protected areas, indicating a lack of enforcement. Natural forests conversion to rubber and pulp plantations has a general negative effect on biodiversity, primarily through habitat fragmentation. The fragmentation analysis showed that natural forests area was reduced and patch number increased, while patch size and connectivity decreased. These land-cover changes threatened local biodiversity, especially island endemic species. Both natural forests losses and fragmentation should be stopped by strict enforcement to prevent further damage. Preserving the remaining natural forests and enforcing the status of protected areas should be a management priority to maximize the watershed's biodiversity conservation value.
4. Food production and nature conservation
NARCIS (Netherlands)
Gordon, Iain J.; Squire, Geoff R.; Prins, Herbert H.T.
2016-01-01
Feeding the world's growing human population is increasingly challenging, especially as more people adopt a western diet and lifestyle. Doing so without causing damage to nature poses an even greater challenge. This book argues that in order to create a sustainable food supply whilst conserving
5. Genetic diversity and the genetic structure of natural populations of Chamaecyparis obtusa: implications for management and conservation.
Science.gov (United States)
Tsumura, Y; Matsumoto, A; Tani, N; Ujino-Ihara, T; Kado, T; Iwata, H; Uchida, K
2007-08-01
We investigated 25 natural populations of Chamaecyparis obtusa using 51 cleaved amplified polymorphic sequence (CAPS) markers, which were developed using information on sequence-tagged sites (STS) in Cryptomeria japonica. Most CAPS markers have codominant expression patterns, and are suitable for population studies because of their robustness and convenience. We estimated various genetic diversity parameters, including average heterozygosity (H(e)) and allelic richness and found that the more peripheral populations tended to have lower genetic diversity than central populations, in agreement with a previous theoretical study. The overall genetic differentiation between populations was low, but statistically significant (G(ST)=0.039), and similar to the level reported in a previous allozyme study. We attempted to detect non-neutral loci associated with local adaptation to clarify the relationship between the fixation index (F(ST)) and H(e) values for each locus and found seven candidates non-neutral loci. Phylogenetic tree analysis of the populations and Bayesian clustering analysis revealed a pattern of gradually increasing isolation of populations with increasing geographical distance. Three populations had a high degree of linkage disequilibrium, which we attribute to severe bottlenecks due to human disturbance or competition with other species during their migration from refugia after the most recent glaciation. We concluded that the small populations in western Japan and in Kanto district are more important, from a conservation perspective, than the populations in central Japan, due to their genetic divergence, relatively small sizes and restricted areas.
6. Nature Conservation Policies and Strategies
Directory of Open Access Journals (Sweden)
Ildiko IOAN
2011-08-01
Full Text Available Humans dependence on nature is beyond doubt one of the most powerfulevidence that supports the thesis of environmental protection. This relation is manifold and it was approached in various frameworks. The paper focuses on the conservation of nature in its narrow sense, meaning natural ecosystems and biodiversity. Although this topic is among the top priorities in environmental policymaking, the progresses recorded to date are not reflecting this position. The analysis aims to highlight the main policies and strategies and the developments for new actions targeting improved effectiveness.
7. An assessment of multidimensional wellbeing in rural Rwanda: impacts of and implications for rural development and natural resource conservation
OpenAIRE
2013-01-01
This study applies a multidimensional definition of wellbeing, which includes material, social and subjective dimensions, to household level social research in rural Rwanda. Its contribution lies in applying the approach to three different fields: the study of cultural difference; natural resource management; and agrarian change, and in combining a wellbeing assessment with dominant theories or concepts in each. Rwanda has received acclaim for meeting development targets despite high level...
8. [Hans Jonas: Nature Conservation, Conservation of Life].
Science.gov (United States)
Burgui Burgui, Mario
2015-01-01
This article discusses three of the problems that the German philosopher Hans Jonas studied. The first one addresses the need for a specific ethic dedicated to the moral dimension of environmental problems, from a different perspective to the traditional. The second problem is crucial in the discussion on environmental ethics: the value of the nature. Does the nature have an intrinsic value or an instrumental value only (to satisfy the interests of the human being)? The thesis of Jonas, which claimed that nature is a good in itself, were further elaborated here. And the third problem is the derivation of moral norms and the role of man in this ethic that recognizes a good in itself in nature. According to Jonas, the human being is not diminished by recognizing the intrinsic value of nature, since the man's uniqueness and value are unquestionable. From these three central issues, the paper highlights the importance of seeking the links between bioethics and environmental ethics to address the current environmental, social and economic crisis.
9. Valuation of nature in conservation and restoration
NARCIS (Netherlands)
Swart, JAA; van der Windt, HJ; Keulartz, J
2001-01-01
Valuation of nature is an important aspect of nature conservation and restoration. Understanding valuation in a broad sense may contribute to conservation strategies since it may lead to better support from society. In this article we propose a model of valuation with respect to conservation and res
10. Conservation of threatened natural habitats
CSIR Research Space (South Africa)
Hall, AV
1984-11-01
Full Text Available The aim of this book is to give a holistic setting to the conservation of plants and animals. Instead of concentrating on species alone, the aim is to spread the concern to the physical and biological features; including humanity that make up...
11. Poverty, livelihoods and the conservation of nature
CSIR Research Space (South Africa)
Bouma, JA
2011-01-01
Full Text Available This paper assesses the linkages between poverty, livelihoods and nature in four biodiversity hotspots in South Africa. To involve communities in protected area management, biodiversity conservation can be improved and negative livelihood impacts...
12. Technology for nature conservation: an industry perspective.
Science.gov (United States)
Joppa, Lucas N
2015-11-01
Information age technology has the potential to change the game for conservation by continuously monitoring the pulse of the natural world. Whether or not it will depends on the ability of the conservation sector to build a community of practice, come together to define key technology challenges and work with a wide variety of partners to create, implement, and sustain solutions. I describe why these steps are necessary, outline the latest developments in the field and offer actionable ways forward for conservation agencies, universities, funding bodies, professional societies, and technology corporations to come together to realize the revolution that computational technologies can bring for biodiversity conservation.
13. Digital technology and the conservation of nature
NARCIS (Netherlands)
Arts, K.A.J.; Wal, van der R.; Adams, W.M.
2015-01-01
Digital technology is changing nature conservation in increasingly profound ways. We describe this impact and its significance through the concept of ‘digital conservation’, which we found to comprise five pivotal dimensions: data on nature, data on people, data integration and analysis, communicati
14. Private Sector Initiatives in Nature Conservation
OpenAIRE
Bennett, Jeffrey W.
1995-01-01
The provision and management of protected natural areas has generally been regarded as the province of governments. Yet there are theoretical arguments to support the contention that the private sector can play a valuable role in nature conservation. There are also numerous examples of private sector initiatives in countries as economically, culturally and environmentally diverse as Australia, New Zealand, Germany and Vanuatu.
15. Conservation Documentation and the Implications of Digitisation
Directory of Open Access Journals (Sweden)
Michelle Moore
2001-11-01
Full Text Available Conservation documentation can be defined as the textual and visual records collected during the care and treatment of an object. It can include records of the object's condition, any treatment done to the object, any observations or conclusions made by the conservator as well as details on the object's past and present environment. The form of documentation is not universally agreed upon nor has it always been considered an important aspect of the conservation profession. Good documentation tells the complete story of an object thus far and should provide as much information as possible for the future researcher, curator, or conservator. The conservation profession will benefit from digitising its documentation using software such as databases and hardware like digital cameras and scanners. Digital technology will make conservation documentation more easily accessible, cost/time efficient, and will increase consistency and accuracy of the recorded data, and reduce physical storage space requirements. The major drawback to digitising conservation records is maintaining access to the information for the future; the notorious pace of technological change has serious implications for retrieving data from any machine- readable medium.
16. Digital technology and the conservation of nature.
Science.gov (United States)
Arts, Koen; van der Wal, René; Adams, William M
2015-11-01
Digital technology is changing nature conservation in increasingly profound ways. We describe this impact and its significance through the concept of 'digital conservation', which we found to comprise five pivotal dimensions: data on nature, data on people, data integration and analysis, communication and experience, and participatory governance. Examining digital innovation in nature conservation and addressing how its development, implementation and diffusion may be steered, we warn against hypes, techno-fix thinking, good news narratives and unverified assumptions. We identify a need for rigorous evaluation, more comprehensive consideration of social exclusion, frameworks for regulation and increased multi-sector as well as multi-discipline awareness and cooperation. Along the way, digital technology may best be reconceptualised by conservationists from something that is either good or bad, to a dual-faced force in need of guidance.
17. NATURE CONSERVATION PROJECTS IN MILITARY DISTRICTS
Directory of Open Access Journals (Sweden)
Milota KUSTROVÁ
2014-04-01
Full Text Available Military areas are very valuable sites from the perspective of nature conservation. The article explains the key factors in maintaining high biodiversity in these areas. It discusses the impact of destructive military activities on building and maintaining valuable habitats of European importance and the necessity to preserve these areas for the conservation of natural values for future generations. Extensive reorganization of the armed forces after the Cold War in Europe has resulted in the decommissioning of a large number of military sites from active military use. Ultimately their changed use has a negative impact on biodiversity. This article informs about the existence and importance of a database of military areas in Central and Eastern Europe and the attempt to declare these as protected areas. At the end of the article mentions LIFE+ projects aimed at the protection of nature in military areas, carried out in the countries of Central and Eastern Europe.
18. A Multi-Scale Approach to Investigating the Red-Crowned Crane-Habitat Relationship in the Yellow River Delta Nature Reserve, China: Implications for Conservation.
Directory of Open Access Journals (Sweden)
Mingchang Cao
Full Text Available The red-crowned crane (Grus japonensis (Statius Müller, 1776 is a rare and endangered species that lives in wetlands. In this study, we used variance partitioning and hierarchical partitioning methods to explore the red-crowned crane-habitat relationship at multiple scales in the Yellow River Delta Nature Reserve (YRDNR. In addition, we used habitat modeling to identify the cranes' habitat distribution pattern and protection gaps in the YRDNR. The variance partitioning results showed that habitat variables accounted for a substantially larger total and pure variation in crane occupancy than the variation accounted for by spatial variables at the first level. Landscape factors had the largest total (45.13% and independent effects (17.42% at the second level. The hierarchical partitioning results showed that the percentage of seepweed tidal flats were the main limiting factor at the landscape scale. Vegetation coverage contributed the greatest independent explanatory power at the plot scale, and patch area was the predominant factor at the patch scale. Our habitat modeling results showed that crane suitable habitat covered more than 26% of the reserve area and that there remained a large protection gap with an area of 20,455 ha, which accounted for 69.51% of the total suitable habitat of cranes. Our study indicates that landscape and plot factors make a relatively large contribution to crane occupancy and that the focus of conservation effects should be directed toward landscape- and plot-level factors by enhancing the protection of seepweed tidal flats, tamarisk-seepweed tidal flats, reed marshes and other natural wetlands. We propose that efforts should be made to strengthen wetland restoration, adjust functional zoning maps, and improve the management of human disturbance in the YRDNR.
19. Changes in the spatial and temporal pattern of natural forest cover on Hainan Island from the 1950s to the 2010s: implications for natural forest conservation and management.
Science.gov (United States)
Lin, Siliang; Jiang, Yaozhu; He, Jiekun; Ma, Guangzhi; Xu, Yang; Jiang, Haisheng
2017-01-01
The study of the past, present, and future state and dynamics of the tropical natural forest cover (NFC) might help to better understand the pattern of deforestation and fragmentation as well as the influence of social and natural processes. The obtained information will support the development of effective conservation policies and strategies. In the present study, we used historical data of the road network, topography, and climatic productivity to reconstruct NFC maps of Hainan Island, China, from the 1950s to the 2010s, using the random forest algorithm. We investigated the spatial and temporal patterns of NFC change from the 1950s to the 2010s and found that it was highly dynamic in both space and time. Our data showed that grid cells with low NFC were more vulnerable to NFC decrease, suggesting that conservation actions regarding natural forests need to focus on regions with low NFC and high ecological value. We also identified the hot spots of NFC change, which provides insights into the dynamic changes of natural forests over time.
20. Conservation implications of anthropogenic impacts on visual communication and camouflage.
Science.gov (United States)
Delhey, Kaspar; Peters, Anne
2017-02-01
Anthropogenic environmental impacts can disrupt the sensory environment of animals and affect important processes from mate choice to predator avoidance. Currently, these effects are best understood for auditory and chemosensory modalities, and recent reviews highlight their importance for conservation. We examined how anthropogenic changes to the visual environment (ambient light, transmission, and backgrounds) affect visual communication and camouflage and considered the implications of these effects for conservation. Human changes to the visual environment can increase predation risk by affecting camouflage effectiveness, lead to maladaptive patterns of mate choice, and disrupt mutualistic interactions between pollinators and plants. Implications for conservation are particularly evident for disrupted camouflage due to its tight links with survival. The conservation importance of impaired visual communication is less documented. The effects of anthropogenic changes on visual communication and camouflage may be severe when they affect critical processes such as pollination or species recognition. However, when impaired mate choice does not lead to hybridization, the conservation consequences are less clear. We suggest that the demographic effects of human impacts on visual communication and camouflage will be particularly strong when human-induced modifications to the visual environment are evolutionarily novel (i.e., very different from natural variation); affected species and populations have low levels of intraspecific (genotypic and phenotypic) variation and behavioral, sensory, or physiological plasticity; and the processes affected are directly related to survival (camouflage), species recognition, or number of offspring produced, rather than offspring quality or attractiveness. Our findings suggest that anthropogenic effects on the visual environment may be of similar importance relative to conservation as anthropogenic effects on other sensory modalities
1. CONSERVATION IMPLICATIONS OF EXPORTING DOMESTIC WOOD HARVEST TO NEIGHBORING COUNTRIES
Science.gov (United States)
Among wealthy countries, increasing imports of natural resources to allow for unchecked consumption and greater domestic environmental conservation has become commonplace. This practice can negatively affect biodiversity conservation planning if natural resource harvest is merely...
2. 7 CFR 654.18 - Natural Resources Conservation Service responsibility.
Science.gov (United States)
2010-01-01
... 7 Agriculture 6 2010-01-01 2010-01-01 false Natural Resources Conservation Service responsibility... Federal Financially-Assisted Projects § 654.18 Natural Resources Conservation Service responsibility. The Natural Resources Conservation Service will assist the sponsor(s) in developing a watershed or...
3. 75 FR 57059 - Montana Department of Natural Resources and Conservation Final Habitat Conservation Plan and...
Science.gov (United States)
2010-09-17
... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR Fish and Wildlife Service Montana Department of Natural Resources and Conservation Final Habitat... received from the Montana Department of Natural Resources and Conservation (DNRC) a Final...
4. Yukawa alignment from natural flavor conservation
CERN Document Server
Cree, Graham
2011-01-01
We study the charged Higgs couplings to fermions in the "democratic" three-Higgs-doublet model, in which one doublet couples to down-type quarks, one to up-type quarks, and one to charged leptons. Flavor-changing neutral Higgs couplings are absent because the Glashow-Weinberg-Paschos condition for natural flavor conservation is in effect. We show that this model reproduces the coupling structure of the charged Higgs boson in the recently-proposed Yukawa-aligned two-Higgs-doublet model, with two subtle constraints that arise from the unitarity of the charged Higgs mixing matrix. Adding a fourth Higgs doublet with no couplings to fermions eliminates these constraints.
5. Local People, Nature Conservation, and Tourism in Northeastern Finland
Directory of Open Access Journals (Sweden)
Anne Tolvanen
2008-06-01
Full Text Available The opinions and perceptions of local communities are central issues in the sustainable management of conservation areas. During 2002 and 2003, we studied the opinions of local people about nature conservation and the development of tourism to investigate whether these opinions were influenced by socioeconomic and demographic factors. Data were collected via a survey of local residents in six areas with different histories of land use, land ownership, conservation, and tourism development. We classified respondents by cluster analysis into three different groups according to their opinions about nature conservation and tourism development: (1 sympathetic to nature conservation, but quite neutral to tourism development (57.7%; (2 critical of nature conservation, but quite neutral to tourism development (30.5%; and (3 quite neutral to nature conservation, but critical of tourism development (11.8%. The most important factors for classification were residential area, age, level of education, primary occupation, indigenousness, frequency of contact with tourists through work, and effects of nature conservation on household economy. On the other hand, gender, level of income, land ownership, land donation for conservation, and income from tourism did not affect opinions concerning nature conservation and tourism development. Almost equal proportions of residents living in close proximity to conservation areas in Kuusamo had positive and negative opinions about nature conservation. Residents living in close proximity to conservation areas regarded conservation as something that might reduce employment and incomes. On the other hand, a greater proportion of residents living near tourist resorts and farther from conservation areas had positive opinions about and perceptions of nature conservation and tourism development. Based on the proportional division of all respondents into the three groups, there may be a coexistent relationship between nature
6. How to Deal with Legitimacy in Nature Conservation Policy?
NARCIS (Netherlands)
Tatenhove, van J.P.M.
2008-01-01
Nature conservation policy has developed from the protection and conservation areas by private parties and governments at the end of the 19th and the beginning of the 20th century to nature development and the creation of ecological networks through Europe in the 1990's. With the introduction of the
7. Digital technology and human development: a charter for nature conservation.
Science.gov (United States)
Maffey, Georgina; Homans, Hilary; Banks, Ken; Arts, Koen
2015-11-01
The application of digital technology in conservation holds much potential for advancing the understanding of, and facilitating interaction with, the natural world. In other sectors, digital technology has long been used to engage communities and share information. Human development-which holds parallels with the nature conservation sector-has seen a proliferation of innovation in technological development. Throughout this Perspective, we consider what nature conservation can learn from the introduction of digital technology in human development. From this, we derive a charter to be used before and throughout project development, in order to help reduce replication and failure of digital innovation in nature conservation projects. We argue that the proposed charter will promote collaboration with the development of digital tools and ensure that nature conservation projects progress appropriately with the development of new digital technologies.
8. The Impact of Nature Experience on Willingness to Support Conservation
Science.gov (United States)
Zaradic, Patricia A.; Pergams, Oliver R. W.; Kareiva, Peter
2009-01-01
We hypothesized that willingness to financially support conservation depends on one's experience with nature. In order to test this hypothesis, we used a novel time-lagged correlation analysis to look at times series data concerning nature participation, and evaluate its relationship with future conservation support (measured as contributions to conservation NGOs). Our results suggest that the type and timing of nature experience may determine future conservation investment. Time spent hiking or backpacking is correlated with increased conservation contributions 11–12 years later. On the other hand, contributions are negatively correlated with past time spent on activities such as public lands visitation or fishing. Our results suggest that each hiker or backpacker translates to $200–$300 annually in future NGO contributions. We project that the recent decline in popularity of hiking and backpacking will negatively impact conservation NGO contributions from approximately 2010–2011 through at least 2018. PMID:19809511
9. Nature Conservation Drones for Automatic Localization and Counting of Animals
NARCIS (Netherlands)
J.C. van Gemert; C.R. Verschoor; P. Mettes; K. Epema; L.P. Koh; S. Wich
2014-01-01
This paper is concerned with nature conservation by automatically monitoring animal distribution and animal abundance. Typically, such conservation tasks are performed manually on foot or after an aerial recording from a manned aircraft. Such manual approaches are expensive, slow and labor intensive
10. Nature Conservation Drones for Automatic Localization and Counting of Animals
NARCIS (Netherlands)
van Gemert, J.C.; Verschoor, C.R.; Mettes, P.; Epema, K.; Koh, L.P.; Wich, S.; Agapito, L.; Bronstein, M.M.; Rother, C.
2015-01-01
This paper is concerned with nature conservation by automatically monitoring animal distribution and animal abundance. Typically, such conservation tasks are performed manually on foot or after an aerial recording from a manned aircraft. Such manual approaches are expensive, slow and labor
11. The social implications of using drones for biodiversity conservation.
Science.gov (United States)
Sandbrook, Chris
2015-11-01
Unmanned aerial vehicles, or 'drones', appear to offer a flexible, accurate and affordable solution to some of the technical challenges of nature conservation monitoring and law enforcement. However, little attention has been given to their possible social impacts. In this paper, I review the possible social impacts of using drones for conservation, including on safety, privacy, psychological wellbeing, data security and the wider understanding of conservation problems. I argue that negative social impacts are probable under some circumstances and should be of concern for conservation for two reasons: (1) because conservation should follow good ethical practice; and (2) because negative social impacts could undermine conservation effectiveness in the long term. The paper concludes with a call for empirical research to establish whether the identified social risks of drones occur in reality and how they could be mitigated, and for self-regulation of drone use by the conservation sector to ensure good ethical practice and minimise the risk of unintended consequences.
12. [The ethical implications of conserving biological samples].
Science.gov (United States)
Tazzite, A; Roky, R; Avard, D
2009-09-01
The conservation and use of biological samples become more and more frequent all around the world. Biobanks of human body substances (blood, urine, DNA, tissues, cells, etc.), and personal data associated with them are created. They have a double character as they are collections of both human biological samples and personal data. In some cases, the gametes, reproductive tissues, embryos, foetal tissue after abortion or even specimens of dead donors are collected and conserved. Although biobanks raise hopes in both the development of new therapies, new drugs and their integration into clinical medicine, they also point to concerns related to ethical questions such as: the principles of information, the consent of the persons concerned, the confidentiality about the personal data, and in some cases discrimination and stigmatisation. Other ethical aspects could raise gradually as research advance. Research being carried out on human sample requires informed free consent from the person who should be able to consent. The donor must be sufficiently informed about the process of research, the purpose, benefits and the risks involved in participating in this research. In the case of persons unable to give consent such minors or persons with mental disabilities, special measures are undertaken. Once the consent was given, the right of withdrawal has been consistently supported by the various declarations and regulations, but some oppose this right for a number of reasons particularly in the case of research on the samples without risk of physical exposure. In this case the notion of human body integrity is different than in research involving therapeutic or clinical intervention. In the case of withdrawal of consent, the samples should be destroyed, but the anonymous results arising from them and their analysis are not affected. What is the case for future uses? Should the researcher obtain again the consent from the donor for a secondary use of the samples? This is a
13. REVIEW: The evolving linkage between conservation science and practice at The Nature Conservancy.
Science.gov (United States)
Kareiva, Peter; Groves, Craig; Marvier, Michelle
2014-10-01
The Nature Conservancy (TNC) was founded by ecologists as a United States land trust to purchase parcels of habitat for the purpose of scientific study. It has evolved into a global organization working in 35 countries 'to conserve the lands and waters on which all life depends'. TNC is now the world 's largest conservation non-governmental organization (NGO), an early adopter of advances in ecological theory and a producer of new science as a result of practising conservation.The Nature Conservancy 's initial scientific innovation was the use of distributional data for rare species and ecological communities to systematically target lands for conservation. This innovation later evolved into a more rigorous approach known as 'Conservation by Design' that contained elements of systematic conservation planning, strategic planning and monitoring and evaluation.The next scientific transition at TNC was a move to landscape-scale projects, motivated by ideas from landscape ecology. Because the scale at which land could be set aside in areas untouched by humans fell far short of the spatial scale demanded by conservation, TNC became involved with best management practices for forestry, grazing, agriculture, hydropower and other land uses.A third scientific innovation at TNC came with the pursuit of multiobjective planning that accounts for economic and resource needs in the same plans that seek to protect biodiversity.The Millennium Ecosystem Assessment prompted TNC to become increasingly concerned with ecosystem services and the material risk to people posed by ecosystem deterioration.Finally, because conservation depends heavily upon negotiation, TNC has recently recruited social scientists, economists and communication experts. One aspect still missing, however, is a solid scientific understanding of thresholds that should be averted.Synthesis and applications. Over its 60-plus year history, scientific advances have informed The Nature Conservancy (TNC) 's actions and
14. Evaluating whether nature's intrinsic value is an axiom of or anathema to conservation.
Science.gov (United States)
Vucetich, John A; Bruskotter, Jeremy T; Nelson, Michael Paul
2015-04-01
That at least some aspects of nature possess intrinsic value is considered by some an axiom of conservation. Others consider nature's intrinsic value superfluous or anathema. This range of views among mainstream conservation professionals potentially threatens the foundation of conservation. One challenge in resolving this disparity is that disparaging portrayals of nature's intrinsic value appear rooted in misconceptions and unfounded presumptions about what it means to acknowledge nature's intrinsic value. That acknowledgment has been characterized as vacuous, misanthropic, of little practical consequence to conservation, adequately accommodated by economic valuation, and not widely accepted in society. We reviewed the philosophical basis for nature's intrinsic value and the implications for acknowledging that value. Our analysis is rooted to the notion that when something possesses intrinsic value it deserves to be treated with respect for what it is, with concern for its welfare or in a just manner. From this basis, one can only conclude that nature's intrinsic value is not a vacuous concept or adequately accommodated by economic valuation. Acknowledging nature's intrinsic value is not misanthropic because concern for nature's welfare (aside from its influence on human welfare) does not in any way preclude also being concerned for human welfare. The practical import of acknowledging nature's intrinsic value rises from recognizing all the objects of conservation concern (e.g., many endangered species) that offer little benefit to human welfare. Sociological and cultural evidence indicates the belief that at least some elements of nature possess intrinsic value is widespread in society. Our reasoning suggests the appropriateness of rejecting the assertion that nature's intrinsic value is anathema to conservation and accepting its role as an axiom. © 2015 Society for Conservation Biology.
15. 75 FR 11194 - San Diego County Water Authority Natural Communities Conservation Program/Habitat Conservation...
Science.gov (United States)
2010-03-10
... Fish and Wildlife Service San Diego County Water Authority Natural Communities Conservation Program/Habitat Conservation Plan, San Diego and Riverside Counties, CA AGENCY: Fish and Wildlife Service... application, and notice of public meetings for the San Diego County Water Authority's (Water Authority...
16. Conservation, biodiversity and infectious disease: scientific evidence and policy implications
Science.gov (United States)
Young, Hillary S.; Wood, Chelsea L.; Kilpatrick, A. Marm; Lafferty, Kevin D.; Nunn, Charles L.; Vincent, Jeffrey R.
2017-01-01
Habitat destruction and infectious disease are dual threats to nature and people. The potential to simultaneously advance conservation and human health has attracted considerable scientific and popular interest; in particular, many authors have justified conservation action by pointing out potential public health benefits . One major focus of this debate—that biodiversity conservation often decreases infectious disease transmission via the dilution effect—remains contentious. Studies that test for a dilution effect often find a negative association between a diversity metric and a disease risk metric, but how such associations should inform conservation policy remains unclear for several reasons. For one, diversity and infection risk have many definitions, making it possible to identify measures that conform to expectations. Furthermore, the premise that habitat destruction consistently reduces biodiversity is in question, and disturbance or conservation can affect disease in many ways other than through biodiversity change. To date, few studies have examined the broader set of mechanisms by which anthropogenic disturbance or conservation might increase or decrease infectious disease risk to human populations. Due to interconnections between biodiversity change, economics and human behaviour, moving from ecological theory to policy action requires understanding how social and economic factors affect conservation.This Theme Issue arose from a meeting aimed at synthesizing current theory and data on ‘biodiversity, conservation and infectious disease’ (4–6 May 2015). Ecologists, evolutionary biologists, economists, epidemiologists, veterinary scientists, public health professionals, and conservation biologists from around the world discussed the latest research on the ecological and socio-economic links between conservation, biodiversity and infectious disease, and the open questions and controversies in these areas. By combining ecological understanding
17. Conservation of Natural and Cultural Heritage in Kenya
OpenAIRE
Deisser, Anne-Marie; Njuguna, Mugwima
2016-01-01
In Kenya, cultural and natural heritage has a particular value. This book brings together essays by heritage experts from different backgrounds, including conservation, heritage management, museum studies, archaeology, environment and social sciences, architecture and landscape, geography, philosophy and economics to explore three key themes: the underlying ethics, practices and legal issues of heritage conservation; the exploration of architectural and urban heritage of Nairobi; and the natu...
18. REVIEW: The evolving linkage between conservation science and practice at The Nature Conservancy
Science.gov (United States)
Kareiva, Peter; Groves, Craig; Marvier, Michelle
2014-01-01
The Nature Conservancy (TNC) was founded by ecologists as a United States land trust to purchase parcels of habitat for the purpose of scientific study. It has evolved into a global organization working in 35 countries ‘to conserve the lands and waters on which all life depends’. TNC is now the world 's largest conservation non-governmental organization (NGO), an early adopter of advances in ecological theory and a producer of new science as a result of practising conservation.The Nature Conservancy 's initial scientific innovation was the use of distributional data for rare species and ecological communities to systematically target lands for conservation. This innovation later evolved into a more rigorous approach known as ‘Conservation by Design’ that contained elements of systematic conservation planning, strategic planning and monitoring and evaluation.The next scientific transition at TNC was a move to landscape-scale projects, motivated by ideas from landscape ecology. Because the scale at which land could be set aside in areas untouched by humans fell far short of the spatial scale demanded by conservation, TNC became involved with best management practices for forestry, grazing, agriculture, hydropower and other land uses.A third scientific innovation at TNC came with the pursuit of multiobjective planning that accounts for economic and resource needs in the same plans that seek to protect biodiversity.The Millennium Ecosystem Assessment prompted TNC to become increasingly concerned with ecosystem services and the material risk to people posed by ecosystem deterioration.Finally, because conservation depends heavily upon negotiation, TNC has recently recruited social scientists, economists and communication experts. One aspect still missing, however, is a solid scientific understanding of thresholds that should be averted.Synthesis and applications. Over its 60-plus year history, scientific advances have informed The Nature Conservancy (TNC) 's
19. Natural Resource Dependency and Decentralized Conservation Within Kanchenjunga Conservation Area Project, Nepal
Science.gov (United States)
Parker, Pete; Thapa, Brijesh
2012-02-01
Kanchenjunga Conservation Area Project (KCAP) in Nepal is among the first protected areas in the world to institute a completely decentralized system of conservation and development. Proponents of decentralized conservation claim that it increases management efficiency, enhances the responsiveness to local needs, and promotes greater equity among local residents. This study assessed local equity by evaluating the levels of dependencies on natural resources among households and the factors affecting that dependency. Data were collected via detailed surveys among 205 randomly selected households within the KCAP. Natural resource dependency was evaluated by comparing the ratio of total household income to income derived from access to natural resources. Economic, social, and access-related variables were employed to determine potential significant predictors of dependency. Overall, households were heavily dependent on natural resources for their income, especially households at higher elevations and those with more adult members. The households that received remittances were most able to supplement their income and, therefore, drastically reduced their reliance on the access to natural resources. Socio-economic variables, such as land holdings, education, caste, and ethnicity, failed to predict dependency. Household participation in KCAP-sponsored training programs also failed to affect household dependency; however, fewer than 20% of the households had any form of direct contact with KCAP personnel within the past year. The success of the KCAP as a decentralized conservation program is contingent on project capacity-building via social mobilization, training programs, and participatory inclusion in decision making to help alleviate the dependency on natural resources.
20. The actual relevance of ecological corridors in nature conservation
Directory of Open Access Journals (Sweden)
Ćurčić Nina B.
2013-01-01
Full Text Available The paper considers theoretical and applied foundations of the concept of the ecological corridors in nature conservation. Their relevance comes from recent ecological phenomenon of habitat fragmentation which is rapidly increasing during last decades. Habitat fragmentation is one of the main threats to richness and diversity of wildlife. Ecological corridors can mitigate the loss and fragmentation of habitat. Corridors perform as “bridges” between habitats for species and they provide a flow of the natural or even anthropogenic caused disturbances. In this paper we will present the meaning and significance of ecological corridors in nature conservation, as well as types of ecological corridors and their ecological benefits. Methodological and practical approaches in nature protection system in Serbia are included. [Projekat Ministarstva nauke Republike Srbije, br. 47007 i br. 176008
1. Understanding and managing compliance in the nature conservation context.
Science.gov (United States)
2015-04-15
Nature conservation relies largely on peoples' rule adherence. However, noncompliance in the conservation context is common: it is one of the largest illegal activities in the world, degrading societies, economies and the environment. Understanding and managing compliance is key for ensuring effective conservation, nevertheless crucial concepts and tools are scattered in a wide array of literature. Here I review and integrate these concepts and tools in an effort to guide compliance management in the conservation context. First, I address the understanding of compliance by breaking it down into five key questions: who?, what?, when?, where? and why?. A special focus is given to 'why?' because the answer to this question explains the reasons for compliance and noncompliance, providing critical information for management interventions. Second, I review compliance management strategies, from voluntary compliance to coerced compliance. Finally, I suggest a system, initially proposed for tax compliance, to balance these multiple compliance management strategies. This paper differs from others by providing a broad yet practical scope on theory and tools for understanding and managing compliance in the nature conservation context.
2. Conservative philanthropists, royalty and business elites in nature conservation in southern Africa
NARCIS (Netherlands)
Spierenburg, M.J.; Wels, H.
2011-01-01
Originally published in 2010 as Volume 42, issue 3 of Antipode. The article investigates the increasingly important connections between the private sector and nature conservation agencies. It looks specifically at the connections between two important philanthropists, the late Anton Rupert, a South
3. Conservative philanthropists, royalty and business elites in nature conservation in southern Africa
NARCIS (Netherlands)
Spierenburg, M.J.; Wels, H.
2010-01-01
The article investigates the increasingly important connections between the private sector and nature conservation agencies. It looks specifically at the connections between two important philanthropists, the late Anton Rupert, a South African business tycoon, and the late Prince Bernhard of The Net
4. Applying the dark diversity concept to nature conservation
DEFF Research Database (Denmark)
Lewis, Rob; de Bello, Francesco; A Bennett, Jonathan;
2016-01-01
presented the greater challenge. Linking patterns to processes is absolutely central to nature conservation because it allows one to identify and resolve problems that adversely impact biodiversity (Watt 1947), one of the ultimate goals of conservation. Still, the large number of mechanisms and processes......-pool framework) (Fig. 1) emphasizes the value of understanding absent species in addition to observed species. Strictly, dark diversity encompasses all species that are currently absent from a site but have the potential to disperse and establish there (Pärtel et al. 2011) (i.e., those species belonging...
5. Experiences in Conservation and Management of Mai Po Nature Reserve of HongKong and Their Implications%香港米埔自然保护区保护与管理经验及启示
Institute of Scientific and Technical Information of China (English)
何诗雨; 胡涛; 徐华林; 史秀华
2016-01-01
随着深圳市城市发展步伐的不断加快，福田红树林自然保护区受到水体污染、人为干扰、病虫害及外来物种等各方面影响，导致其生态系统出现不同程度的退化。通过赴香港米埔自然保护区考察与学习，分析了香港米埔自然保护区精细化管理、生态系统日趋稳定及教育宣传等经验，提出了深圳福田乃至全国红树林自然保护区保护与管理对策和建议。%With the rapid economic development of Shenzhen, the mangrove forest in Futian Nature Reserve was affected by various factors, such as water pollution, human disturbance, pests, diseases, and invasive species, which resulted in ecosystem degradation of the mangrove forest. By visiting Hong Kong Mai Po Nature Reserve, countermeasures and suggestions were proposed for conservation and management of mangrove forest in Shenzhen and other regions in China.
6. Aligning Natural Resource Conservation and Flood Hazard Mitigation in California.
Directory of Open Access Journals (Sweden)
Juliano Calil
Full Text Available Flooding is the most common and damaging of all natural disasters in the United States, and was a factor in almost all declared disasters in U.S.Direct flood losses in the U.S. in 2011 totaled $8.41 billion and flood damage has also been on the rise globally over the past century. The National Flood Insurance Program paid out more than$38 billion in claims since its inception in 1968, more than a third of which has gone to the one percent of policies that experienced multiple losses and are classified as "repetitive loss." During the same period, the loss of coastal wetlands and other natural habitat has continued, and funds for conservation and restoration of these habitats are very limited. This study demonstrates that flood losses could be mitigated through action that meets both flood risk reduction and conservation objectives. We found that there are at least 11,243km2 of land in coastal California, which is both flood-prone and has natural resource conservation value, and where a property/structure buyout and habitat restoration project could meet multiple objectives. For example, our results show that in Sonoma County, the extent of land that meets these criteria is 564km2. Further, we explore flood mitigation grant programs that can be a significant source of funds to such projects. We demonstrate that government funded buyouts followed by restoration of targeted lands can support social, environmental, and economic objectives: reduction of flood exposure, restoration of natural resources, and efficient use of limited governmental funds.
7. Murray GRAY, Geodiversity, valuing and conserving abiotic nature
OpenAIRE
2007-01-01
« Geodiversity : valuing and conserving abiotic nature » est un ouvrage dédié exclusivement à la conservation et à la valorisation du patrimoine géologique et géomorphologique de la Terre, y compris pédologique. Comme le souligne l’auteur, le terme géodiversité est fortement lié à d’autres néologismes tels que géoconservation, géohéritage ou encore géo-indicateurs. Tous ces termes défendent l’idée que les activités humaines menacent la diversité des roches, des sols et des formes du relief ai...
8. Implications of Current Ecological Thinking for Biodiversity Conservation: a Review of the Salient Issues
Directory of Open Access Journals (Sweden)
Richard J. Hobbs
2005-06-01
Full Text Available Given escalating concern worldwide about the loss of biodiversity, and given biodiversity's centrality to quality of life, it is imperative that current ecological knowledge fully informs societal decision making. Over the past two decades, ecological science has undergone many significant shifts in emphasis and perspective, which have important implications for how we manage ecosystems and species. In particular, a shift has occurred from the equilibrium paradigm to one that recognizes the dynamic, non-equilibrium nature of ecosystems. Revised thinking about the spatial and temporal dynamics of ecological systems has important implications for management. Thus, it is of growing concern to ecologists and others that these recent developments have not been translated into information useful to managers and policy makers. Many conservation policies and plans are still based on equilibrium assumptions. A fundamental difficulty with integrating current ecological thinking into biodiversity policy and management planning is that field observations have yet to provide compelling evidence for many of the relationships suggested by non-equilibrium ecology. Yet despite this scientific uncertainty, management and policy decisions must still be made. This paper was motivated by the need for considered scientific debate on the significance of current ideas in theoretical ecology for biodiversity conservation. This paper aims to provide a platform for such discussion by presenting a critical synthesis of recent ecological literature that (1 identifies core issues in ecological theory, and (2 explores the implications of current ecological thinking for biodiversity conservation.
9. Implications of human value shift and persistence for biodiversity conservation.
Science.gov (United States)
Manfredo, Michael J; Teel, Tara L; Dietsch, Alia M
2016-04-01
Large-scale change in human values and associated behavior change is believed by some to be the ultimate solution to achieve global biodiversity conservation. Yet little is known about the dynamics of values. We contribute to this area of inquiry by examining the trajectory of values affecting views of wildlife in North America. Using data from a 19-state study in the United States and global data from the Schwartz Value Survey, we explored questions of value persistence and change and the nature of attitudinal responses regarding wildlife conservation issues. We found support, based on subjects' ancestry, for the supposition that domination is a prevalent American value orientation toward wildlife that has origins in European Judeo-Christian traditions. Independent of that effect, we also found indications of change. Modernization is contributing to a shift from domination to mutualism value orientations, which is fostering attitudes less centered on human interests and seemingly more consistent with a biocentric philosophy. Our findings suggest that if value shift could be achieved in a purposeful way, then significant and widespread behavior change believed necessary for long-term conservation success may indeed be possible. In particular, greater emphasis on mutualism values may help provide the context for more collaborative approaches to support future conservation efforts. However, given the societal forces at play, it is not at all clear that human-engineered value shift is tenable. Instead of developing strategies aimed at altering values, it may be more productive to create strategies that recognize and work within the boundaries of existing values. Whereas values appear to be in a period of flux, it will be difficult to predict future trends without a better understanding of value formation and shift, particularly under conditions of rapid social-ecological change. © 2016 Society for Conservation Biology.
10. Effects of bioenergy production on European nature conservation options
Science.gov (United States)
Schleupner, C.; Schneider, U. A.
2009-04-01
To increase security of energy supply and reduce greenhouse gas (GHG) emissions the European Commission set out a long-term strategy for renewable energy in the European Union (EU). Bioenergy from forestry and agriculture plays a key role for both. Since the last decade a significant increase of biomass energy plantations has been observed in Europe. Concurrently, the EU agreed to halt the loss of biodiversity within its member states. One measure is the Natura2000 network of important nature sites that actually covers about 20% of the EU land surface. However, to fulfil the biodiversity target more nature conservation and restoration sites need to be designated. There are arising concerns that an increased cultivation of bioenergy crops will decrease the land available for nature reserves and for "traditional" agriculture and forestry. In the following the economic and ecological impacts of structural land use changes are demonstrated by two examples. First, a case study of land use changes on the Eiderstedt peninsula in Schleswig-Holstein/Germany evaluates the impacts of grassland conversion into bioenergy plantations under consideration of selected meadow birds. Scenarios indicate not only a quantitative loss of habitats but also a reduction of habitat quality. The second study assesses the role of bioenergy production in light of possible negative impacts on potential wetland conservation sites in Europe. By coupling the spatial wetland distribution model "SWEDI" (cf. SCHLEUPNER 2007) to the European Forest and Agricultural Sector Optimization Model (EUFASOM; cf. SCHNEIDER ET AL. 2008) economic and environmental aspects of land use are evaluated simultaneously. This way the costs and benefits of the appropriate measures and its consequences for agriculture and forestry are investigated. One aim is to find the socially optimal balance between alternative wetland uses by integrating biological benefits - in this case wetlands - and economic opportunities - here
11. Implications of Ebola virus disease on wildlife conservation in Nigeria.
Science.gov (United States)
2015-01-01
The recent Ebola Virus Disease outbreak in some West African countries spanning from late 2013 and currently on as of 13th March, 2015 is the most widespread and fatal with human mortality that has surpassed all previous outbreaks. The outbreak has had its toll on conservation of endangered species. This portends danger for the wild fauna of the country if proactive measures are not taken to prepare grounds for evidence-based assertions concerning the involvement of wild species. To this end, there is an urgent need for sweeping census of reserves, national parks and wetlands. As well as the creation of a system involving reportage by sectors like the industries (extractive and construction) including persons and organisations involved with wildlife related activities. This documentation of die offs and unusual events to collaborating institutions, will help in monitoring trends which hitherto would have gone unnoticed. The importance of bats and primates in agriculture and public health via consumption of vermin insects and seed dispersal cannot be over-emphasized. There is the need for caution on the tendencies to destroy indicator species which could be silent pointers to emerging or re-emerging health and environmental issues. Wildlife resources are still reliably useful and caution is advised in the use of blanket destructive policies like fumigation of caves, indiscriminate culling and poisoned baits to destroy supposedly Ebola Disease Virus wildlife reservoirs. This paper highlights the immediate conservation problems and likely future implications of Ebola saga in Nigeria. It tries to identify the gaps in wildlife researches and makes recommendations for probable workable conservation strategies.
12. Ecology and Conservation of Steppes and Semi-Natural Grasslands
Directory of Open Access Journals (Sweden)
Valkó Orsolya
2016-12-01
Full Text Available Palaearctic grasslands encompass a diverse variety of habitats, many of high nature value and vulnerability. The main challenges are climate-change, land-use change, agricultural intensification and abandonment. Many measures are in place to address these challenges, through restoration and appropriate management, though more work is necessary. We present eight studies from China/Germany, Greece, Kazakhstan, Russia and Ukraine. The papers cover a wide range of grassland and steppe habitats and cover vegetation ecology, syntaxonomy and zoology. We also conducted a systematic search on steppe and grassland diversity. The greatest number of studies was from China, followed by Germany and England. We conclude that the amount of research being carried out on Eurasian grasslands is inadequate considering their high levels of biodiversity and vulnerability. We hope to encourage readers to address current major challenges, such as how to manage grasslands for the benefit of diverse taxa, to ensure that conservation initiatives concentrate on sites where there is good potential for success and for the generation of realistic and viable conservation strategies.
13. Conservation Narratives and Their Implications in the Coral Triangle Initiative
Directory of Open Access Journals (Sweden)
Samantha Berdej
2015-01-01
Full Text Available Conserving coral reefs, sustaining fisheries, and ensuring food security are multi-faceted challenges. Six nations in the Southeast Asia Coral Triangle have agreed to a region-wide framework to address these challenges through the Coral Triangle Initiative on Coral Reefs, Fisheries and Food Security (CTI. Based on a review of documentation, selected discussions and ongoing work in the region, we offer an initial assessment of narratives influencing conservation practice in the CTI. Current efforts in the CTI are framed by a crisis narrative that emphasises the importance of maintaining critical ecosystems and baseline conditions. This narrative has a strong empirical basis but it can also exacerbate a dualistic view of people and nature. However, CTI documentation and programming also reflect a recognition of linked social-ecological change and the historical co-evolution of communities and coastal-marine systems. This emerging narrative places an emphasis on building resilience to change, rather than resisting change. We do not advocate here for a single narrative with which to frame policy responses in the CTI, but rather draw attention to the ways that mainstreaming of certain narratives will have material effects on initiatives and programmes promoted in this region of globally significant marine biodiversity.
14. Patrones biogeográficos de los tenebriónidos epigeos (Coleoptera: Tenebrionidae del Área Natural Protegida Península Valdés, Argentina: implicaciones para su conservación Biogeographic patterns of epigean tenebrionids (Coleoptera: Tenebrionidae from Protected Natural Area Península Valdés, Argentina: implications for its conservation
Directory of Open Access Journals (Sweden)
Rodolfo Carrara
2011-12-01
inhabit the peninsula, although it was estimated that the total richness of the area should be 27 species. In addition, it was recognized that the species range sizes follow a log-normal distribution and that only three species are endemic. The spatial distribution of richness was aggregate within the peninsula and we can identify 10 "hotspots". Finally, considering that in the Península Valdés are allowed productive activities that cause significant habitat degradation, we discuss the implicances that have these findings for epigean tenebrionids conservation.
15. Diversity Storage: Implications for tropical conservation and restoration
Directory of Open Access Journals (Sweden)
Henry F. Howe
2014-12-01
Full Text Available The future of tropical biodiversity in human-dominated landscapes will be conservation and restoration of processes of seed dispersal by birds and mammals. Here the Diversity Storage Hypothesis posits that immense biological diversity resides within skewed species-abundance distributions of tropical trees, and further predicts that many species will adjust to increases of 1.5–3.0 °C anticipated from climate change by 2100. Common and widespread tropical trees (>100,000,000 individuals may shift ranges but are unlikely to face extinction. Many rare species (e.g. <1000 individuals have a more precarious future. The latter may be declining species bound for extinction, incipient species adjusting to environmental changes, or relics of past warmer and more seasonal climates that will be resurrected if processes of seed dispersal allow them to persist and spread. In fragmented agricultural landscapes, preserved or planted corridors, buffers and stepping-stone habitat patches around and between forest remnants are more vital than efforts to preserve or create contemporary forest compositions, dominance relations, and species-abundance distributions. An implication of Diversity Storage is that it is more important to facilitate migration into and out of changing landscapes to allow inherent diversity to adjust and coexist with agricultural economies than to resist change.
16. Wildlife tuberculosis in South African conservation areas: implications and challenges.
Science.gov (United States)
Michel, A L; Bengis, R G; Keet, D F; Hofmeyr, M; Klerk, L M de; Cross, P C; Jolles, A E; Cooper, D; Whyte, I J; Buss, P; Godfroid, J
2006-02-25
Tuberculosis, caused by Mycobacterium bovis, was first diagnosed in African buffalo in South Africa's Kruger National Park in 1990. Over the past 15 years the disease has spread northwards leaving only the most northern buffalo herds unaffected. Evidence suggests that 10 other small and large mammalian species, including large predators, are spillover hosts. Wildlife tuberculosis has also been diagnosed in several adjacent private game reserves and in the Hluhluwe-iMfolozi Park, the third largest game reserve in South Africa. The tuberculosis epidemic has a number of implications, for which the full effect of some might only be seen in the long-term. Potential negative long-term effects on the population dynamics of certain social animal species and the direct threat for the survival of endangered species pose particular problems for wildlife conservationists. On the other hand, the risk of spillover infection to neighboring communal cattle raises concerns about human health at the wildlife-livestock-human interface, not only along the western boundary of Kruger National Park, but also with regards to the joint development of the Greater Limpopo Transfrontier Conservation Area with Zimbabwe and Mozambique. From an economic point of view, wildlife tuberculosis has resulted in national and international trade restrictions for affected species. The lack of diagnostic tools for most species and the absence of an effective vaccine make it currently impossible to contain and control this disease within an infected free-ranging ecosystem. Veterinary researchers and policy-makers have recognized the need to intensify research on this disease and the need to develop tools for control, initially targeting buffalo and lion.
17. 78 FR 40425 - Draft Environmental Assessment for the J. Phil Campbell, Senior, Natural Resource Conservation...
Science.gov (United States)
2013-07-05
...; ] DEPARTMENT OF AGRICULTURE Draft Environmental Assessment for the J. Phil Campbell, Senior, Natural Resource... Environmental Assessment for the J. Phil Campbell, Senior, Natural Resource Conservation Center Land Transfer... of land at the J. Phil Campbell, Senior (JPC), Natural Resource Conservation Center (NRCC) from the...
18. 76 FR 52635 - Notice of Proposed Changes to the National Handbook of Conservation Practices for the Natural...
Science.gov (United States)
2011-08-23
... conservation practice standards used to carry out HEL and wetland provisions of the law. DATES: Effective Date... Natural Resources Conservation Service Notice of Proposed Changes to the National Handbook of Conservation Practices for the Natural Resources Conservation Service AGENCY: Natural Resources Conservation...
19. 76 FR 1595 - Notice of Proposed Changes to the National Handbook of Conservation Practices for the Natural...
Science.gov (United States)
2011-01-11
... revisions to conservation practice standards used to carry out HEL and wetland provisions of the law. DATES... Natural Resources Conservation Service Notice of Proposed Changes to the National Handbook of Conservation Practices for the Natural Resources Conservation Service AGENCY: Natural Resources Conservation...
20. 75 FR 33761 - Notice of Proposed Changes to the National Handbook of Conservation Practices for the Natural...
Science.gov (United States)
2010-06-15
... revisions to conservation practice standards used to carry out HEL and wetland provisions of the law. DATES... Natural Resources Conservation Service Notice of Proposed Changes to the National Handbook of Conservation Practices for the Natural Resources Conservation Service AGENCY: Natural Resources Conservation...
1. 75 FR 4525 - Notice of Proposed Changes to the National Handbook of Conservation Practices for the Natural...
Science.gov (United States)
2010-01-28
... conservation systems that treat highly erodible land (HEL) or on land determined to be a wetland. Section 343... Natural Resources Conservation Service Notice of Proposed Changes to the National Handbook of Conservation Practices for the Natural Resources Conservation Service AGENCY: Natural Resources Conservation...
2. 77 FR 74456 - Notice of Proposed Changes to the National Handbook of Conservation Practices for the Natural...
Science.gov (United States)
2012-12-14
... revisions to conservation practice standards used to carry out HEL and wetland provisions of the law. DATES... Natural Resources Conservation Service Notice of Proposed Changes to the National Handbook of Conservation Practices for the Natural Resources Conservation Service AGENCY: Natural Resources Conservation...
3. Biologists Bridging Science and the Conservation Movement : The Rise of Nature Conservation and Nature Management in the Netherlands, 1850-1950
NARCIS (Netherlands)
van der Windt, Henny J.
This paper investigates the importance and various roles of amateur naturalists and biologists in the conservation movement between 1850 and 1950, in particular in the Netherlands. It is concluded that biological sciences were important resources for Dutch nature conservation, although the extent of
4. Biologists Bridging Science and the Conservation Movement : The Rise of Nature Conservation and Nature Management in the Netherlands, 1850-1950
NARCIS (Netherlands)
van der Windt, Henny J.
2012-01-01
This paper investigates the importance and various roles of amateur naturalists and biologists in the conservation movement between 1850 and 1950, in particular in the Netherlands. It is concluded that biological sciences were important resources for Dutch nature conservation, although the extent of
5. Coupled human and natural systems approach to wildlife research and conservation
Directory of Open Access Journals (Sweden)
Neil H. Carter
2014-09-01
Full Text Available Conserving wildlife while simultaneously meeting the resource needs of a growing human population is a major sustainability challenge. As such, using combined social and environmental perspectives to understand how people and wildlife are interlinked, together with the mechanisms that may weaken or strengthen those linkages, is of utmost importance. However, such integrated information is lacking. To help fill this information gap, we describe an integrated coupled human and natural systems (CHANS approach for analyzing the patterns, causes, and consequences of changes in wildlife population and habitat, human population and land use, and their interactions. Using this approach, we synthesize research in two sites, Wolong Nature Reserve in China and Chitwan National Park in Nepal, to explicate key relationships between people and two globally endangered wildlife conservation icons, the giant panda and the Bengal tiger. This synthesis reveals that local resident characteristics such as household socioeconomics and demography, as well as community-level attributes such as resource management organizations, affect wildlife and their habitats in complex and even countervailing ways. Human impacts on wildlife and their habitats are in turn modifying the suite of ecosystem services that they provide to local residents in both sites, including access to forest products and cultural values. These interactions are further complicated by human and natural disturbance (e.g., civil wars, earthquakes, feedbacks (including policies, and telecouplings (socioeconomic and environmental interactions over distances that increasingly link the focal systems with other distant systems. We highlight several important implications of using a CHANS approach for wildlife research and conservation that is useful not only in China and Nepal but in many other places around the world facing similar challenges.
6. Tibet natural conservation areas rank first in China
Institute of Scientific and Technical Information of China (English)
2005-01-01
According to statistics conducted by the Environment Bureau of T.A.R，Tibet has established 7 different conservation areas at national level, 8 at provincial level, and 23 at sub-provincial level. The total conservation area reaches to 407,000 sq km, This number accounts for one third oft A. R, and ranks number one in China.
7. Biological Conservation of Giant Limpets: The Implications of Large Size.
Science.gov (United States)
Espinosa, F; Rivera-Ingraham, G A
Patellogastropods, also known as true limpets, are distributed throughout the world and constitute key species in coastal ecosystems. Some limpet species achieve remarkable sizes, which in the most extreme cases can surpass 35cm in shell length. In this review, we focus on giant limpets, which are defined as those with a maximum shell size surpassing 10cm. According to the scientific literature, there are a total of 14 species across five genera that reach these larger sizes. Four of these species are threatened or in danger of extinction. Inhabiting the intertidal zones, limpets are frequently affected by anthropogenic impacts, namely collection by humans, pollution and habitat fragmentation. In the case of larger species, their conspicuous size has made them especially prone to human collection since prehistoric times. Size is not phylogeny-dependent among giant limpets, but is instead related to behavioural traits instead. Larger-sized species tend to be nonmigratory and territorial compared to those that are smaller. Collection by humans has been cited as the main cause behind the decline and/or extinction of giant limpet populations. Their conspicuously large size makes them the preferred target of human collection. Because they are protandric species, selectively eliminating larger specimens of a given population seriously compromises their viability and has led to local extinction events in some cases. Additionally, sustained collection over time may lead to microevolutionary responses that result in genetic changes. The growing presence of artificial structures in coastal ecosystems may cause population fragmentation and isolation, limiting the genetic flow and dispersion capacity of many limpet species. However, when they are necessitated, artificial structures could be managed to establish marine artificial microreserves and contribute to the conservation of giant limpet species that naturally settle on them. © 2017 Elsevier Ltd. All rights reserved.
8. Sixteen years of change in the global terrestrial human footprint and implications for biodiversity conservation
Science.gov (United States)
Venter, Oscar; Sanderson, Eric W.; Magrach, Ainhoa; Allan, James R.; Beher, Jutta; Jones, Kendall R.; Possingham, Hugh P.; Laurance, William F.; Wood, Peter; Fekete, Balázs M.; Levy, Marc A.; Watson, James E. M.
2016-01-01
Human pressures on the environment are changing spatially and temporally, with profound implications for the planet's biodiversity and human economies. Here we use recently available data on infrastructure, land cover and human access into natural areas to construct a globally standardized measure of the cumulative human footprint on the terrestrial environment at 1 km2 resolution from 1993 to 2009. We note that while the human population has increased by 23% and the world economy has grown 153%, the human footprint has increased by just 9%. Still, 75% the planet's land surface is experiencing measurable human pressures. Moreover, pressures are perversely intense, widespread and rapidly intensifying in places with high biodiversity. Encouragingly, we discover decreases in environmental pressures in the wealthiest countries and those with strong control of corruption. Clearly the human footprint on Earth is changing, yet there are still opportunities for conservation gains. PMID:27552116
9. Sixteen years of change in the global terrestrial human footprint and implications for biodiversity conservation
Science.gov (United States)
Venter, Oscar; Sanderson, Eric W.; Magrach, Ainhoa; Allan, James R.; Beher, Jutta; Jones, Kendall R.; Possingham, Hugh P.; Laurance, William F.; Wood, Peter; Fekete, Balázs M.; Levy, Marc A.; Watson, James E. M.
2016-08-01
Human pressures on the environment are changing spatially and temporally, with profound implications for the planet's biodiversity and human economies. Here we use recently available data on infrastructure, land cover and human access into natural areas to construct a globally standardized measure of the cumulative human footprint on the terrestrial environment at 1 km2 resolution from 1993 to 2009. We note that while the human population has increased by 23% and the world economy has grown 153%, the human footprint has increased by just 9%. Still, 75% the planet's land surface is experiencing measurable human pressures. Moreover, pressures are perversely intense, widespread and rapidly intensifying in places with high biodiversity. Encouragingly, we discover decreases in environmental pressures in the wealthiest countries and those with strong control of corruption. Clearly the human footprint on Earth is changing, yet there are still opportunities for conservation gains.
10. Hybrid zone and its genetic analysis： implication for conservation
Institute of Scientific and Technical Information of China (English)
ZHENGDong; LIUXue-dong; MAJian-zhang
2003-01-01
Hybrid zone is a very critical concept within the evolutionary biology, because it would offer us a better insight to understand the evolutionary role of gene flow and hybridization based on the cline model. This minireview presents an expatia-tion of history perspectives and research developments upon basic concepts including hybrid zones, hybridization, hybrid and its the genetic cline model. Moreover, by figuring out the existing problem around the hybrids within conservative theory and prac-tices, it suggests that the theory of hybrid zone be introduced into conservation biology and it would be provide a broader and more open theoretical background for conservative research and practices.
11. The implications of globalization for conservation in Africa
CSIR Research Space (South Africa)
Mwampamba, TH
2016-06-01
Full Text Available countries. ACCBs provide the space and platform to share and discuss recent research findings and conservation experiences, to build networks, to form collaborations and to identify strategies for addressing the meeting¿s theme....
12. Group decisions in biodiversity conservation: implications from game theory.
Directory of Open Access Journals (Sweden)
David M Frank
Full Text Available BACKGROUND: Decision analysis and game theory have proved useful tools in various biodiversity conservation planning and modeling contexts. This paper shows how game theory may be used to inform group decisions in biodiversity conservation scenarios by modeling conflicts between stakeholders to identify Pareto-inefficient Nash equilibria. These are cases in which each agent pursuing individual self-interest leads to a worse outcome for all, relative to other feasible outcomes. Three case studies from biodiversity conservation contexts showing this feature are modeled to demonstrate how game-theoretical representation can inform group decision-making. METHODOLOGY AND PRINCIPAL FINDINGS: The mathematical theory of games is used to model three biodiversity conservation scenarios with Pareto-inefficient Nash equilibria: (i a two-agent case involving wild dogs in South Africa; (ii a three-agent raptor and grouse conservation scenario from the United Kingdom; and (iii an n-agent fish and coral conservation scenario from the Philippines. In each case there is reason to believe that traditional mechanism-design solutions that appeal to material incentives may be inadequate, and the game-theoretical analysis recommends a resumption of further deliberation between agents and the initiation of trust--and confidence--building measures. CONCLUSIONS AND SIGNIFICANCE: Game theory can and should be used as a normative tool in biodiversity conservation contexts: identifying scenarios with Pareto-inefficient Nash equilibria enables constructive action in order to achieve (closer to optimal conservation outcomes, whether by policy solutions based on mechanism design or otherwise. However, there is mounting evidence that formal mechanism-design solutions may backfire in certain cases. Such scenarios demand a return to group deliberation and the creation of reciprocal relationships of trust.
13. Study on the Effects of Natural Factors on Water Conservation Capacity of Qilian Mountain
Institute of Scientific and Technical Information of China (English)
2011-01-01
[Objective]The study aimed at analyzing the effects of natural factors on water conservation capacity of Qilian Mountain.[Method] Based on water conservation quantity,elevation data and SPOT-VEGETATION remote sensing data of Qilian Mountain in 2003,the relationship between water conservation quantity and influencing factors like elevation,slope,aspect and vegetation index varying greatly in the studied area was analyzed quantitatively by means of statistical method,and the effects of natural factors on wate...
14. 75 FR 79013 - Santa Clara Valley Habitat Conservation Plan and Natural Community Conservation Plan, CA...
Science.gov (United States)
2010-12-17
...; or Eric Tattersall, Deputy Assistant Field Supervisor/Division Chief, Conservation Planning and... Library. 6445 Camden Avenue, San Jose, CA 95120. 2. Dr. Martin Luther King, Jr. Library. 150 E...
15. Multipole charge conservation and implications on electromagnetic radiation
CERN Document Server
Seraj, Ali
2016-01-01
It is shown that conserved charges associated with a specific subclass of gauge symmetries of Maxwell electrodynamics are proportional to the well known electric multipole moments. The symmetries are residual gauge transformations surviving after fixing the Lorenz gauge, and have nontrivial charge. These "Multipole charges" receive contributions both from the charged matter and electromagnetic fields. The former is nothing but the electric multipole moment of the source. In a stationary configuration, there is a novel equipartition relation between the two contributions. The multipole charge, while conserved, can freely interpolate between the source and the electromagnetic field, and therefore can be propagated with the radiation. Using the multipole charge conservation, we obtain infinite number of constraints over the radiation produced by the dynamics of charged matter.
16. goal management as an attempt to evaluate nature conservation ...
African Journals Online (AJOL)
some methodological implications of evaluation research. A practical model ... be preferable to quantitative research designs when assessing .... A survey questioning evaluation methods was sent to some 350 ... questionnaires were completed by the teachers. (78,4%) and .... In the final analysis all strategies being used for.
17. Low-Intensity Agricultural Landscapes in Transylvania Support High Butterfly Diversity: Implications for Conservation
Science.gov (United States)
Loos, Jacqueline; Dorresteijn, Ine; Hanspach, Jan; Fust, Pascal; Rakosy, László; Fischer, Joern
2014-01-01
European farmland biodiversity is declining due to land use changes towards agricultural intensification or abandonment. Some Eastern European farming systems have sustained traditional forms of use, resulting in high levels of biodiversity. However, global markets and international policies now imply rapid and major changes to these systems. To effectively protect farmland biodiversity, understanding landscape features which underpin species diversity is crucial. Focusing on butterflies, we addressed this question for a cultural-historic landscape in Southern Transylvania, Romania. Following a natural experiment, we randomly selected 120 survey sites in farmland, 60 each in grassland and arable land. We surveyed butterfly species richness and abundance by walking transects with four repeats in summer 2012. We analysed species composition using Detrended Correspondence Analysis. We modelled species richness, richness of functional groups, and abundance of selected species in response to topography, woody vegetation cover and heterogeneity at three spatial scales, using generalised linear mixed effects models. Species composition widely overlapped in grassland and arable land. Composition changed along gradients of heterogeneity at local and context scales, and of woody vegetation cover at context and landscape scales. The effect of local heterogeneity on species richness was positive in arable land, but negative in grassland. Plant species richness, and structural and topographic conditions at multiple scales explained species richness, richness of functional groups and species abundances. Our study revealed high conservation value of both grassland and arable land in low-intensity Eastern European farmland. Besides grassland, also heterogeneous arable land provides important habitat for butterflies. While butterfly diversity in arable land benefits from heterogeneity by small-scale structures, grasslands should be protected from fragmentation to provide
18. 77 FR 74500 - Proposed Habitat Conservation Plan/Natural Community Conservation Plan for Western Butte County...
Science.gov (United States)
2012-12-14
... Marine Fisheries Service (NMFS), and the California Department of Fish and Game (CDFG), intend to gather... development of open space and conservation elements that dovetail with the BRCP. The proposed BRCP is designed... species, covered activities, permit area, or a combination of these elements. The EIS/EIR will...
19. Why There Are No Conservative Professors and Why Do Conservatives Care: Implications for Christian Scholarship
Science.gov (United States)
Brow, Mark V.
2017-01-01
The dearth of conservative professors in many disciplinary fields in higher education has been the concern, oddly enough, of liberal scholars. Perhaps one of the most prolific apologists of the liberal professorate has been professor of sociology Neil Gross at the University of British Columbia. Gross attributes the abundance of liberal professors…
20. Conservation for cities how to plan and build natural infrastructure
CERN Document Server
McDonald, Robert I
2015-01-01
With this book, Robert McDonald offers a comprehensive framework for maintaining and strengthening the supporting bonds between cities and nature through innovative infrastructure projects. It's time to think differently about cities and nature. More people than ever live in cities, and all of this urban growth, along with challenges of adapting to climate change, will require a new approach to infrastructure if we're going to create livable urban places. After presenting a broad approach to incorporating natural infrastructure priorities into urban planning, he focuses each following chapter on a specific ecosystem service. He describes a wide variety of benefits, and helps practitioners answer fundamental questions about how to use natural infrastructure to create communities that are more resilient and livable.
1. Protected Areas legislation and the conservation of the Colombian Orinoco Basin natural ecosystems
Directory of Open Access Journals (Sweden)
Ana Aldana
2013-02-01
Full Text Available Colombia has shown a strong commitment to the achievement of the CBD´s biodiversity target, by promoting the conservation of at least 10% of its natural ecosystems. Protected Area categories in Colombia are undergoing a standardization process that should enhance the country´s capacity to protect its natural ecosystems. In this study we use a spatial analysis to examine how the legislation and the civil society´s initiatives help in the conservation of natural ecosystems in the Colombian Orinoco Basin. We found that differentiation in use restriction legislation limits the conservation potential of some Protected Area categories. The only fully Protected Areas in Colombia are the Natural National Parks System Areas, which protect only 10% of the area of natural ecosystems and less than 50% of the natural ecosystems in the Colombian Orinoco Basin. Indigenous Reserves help significantly in the conservation of the natural ecosystems in the Colombian Orinoco Basin, but are not a Protected Area category, making it difficult for indigenous groups to aid in the accomplishment of conservation goals in Colombia.A small percentage of ecosystems of the Colombian Orinoco Basin fall outside of any Protected Area or Indigenous Reserve and urgent actions may be needed to protect them. Future similar studies should use current and updated information on Protected Areas and take into account changes in land cover, for a better understanding of the role of different categories of Protected Areas in the achievement of conservation objectives in Colombia.
2. Integrating ecological knowledge with legal instruments for nature conservation in river management
NARCIS (Netherlands)
Nooij, Reinier Jacobus Willem de
2006-01-01
Legal instruments for nature conservation make knowledge on actual and potential presence of protected and endangered species in river floodplain ecosystems an important issue in river management. Within river management, many physical reconstruction and management plans are currently being carried
3. The Role of Views of Nature in Dutch Nature Conservation: the case of the Creation of a Drift Sand Area in the Hoge Veluwe National Park
NARCIS (Netherlands)
Turnhout, E.; Hisschemoller, M.; Eijsackers, H.J.P.
2004-01-01
Nature conservation requires choices about what sort of nature should be protected in what areas and includes value judgments on what nature is and/or should be. This paper studies the role of differing views of nature in nature conservation. A case study on the creation of a drift sand area in the
4. The Function and Value of Water Conservation of Forest Ecosystem in Gongbo Nature Reserve of Tibet
Institute of Scientific and Technical Information of China (English)
2012-01-01
Gongbo Nature Reserve, located in Nyingchi of Tibet, is by far the largest construction project of forest reserves that China approves and invests in. This article adopts the shadow project method, and estimates the water conservation function of forest ecosystem of Gongbo Nature Reserve based on the Specifications for Assessment of Forest Ecosystem Services in China promulgated by State Forestry Administration of China. The results show that the total value of water conservation of forest ecosystem in Gongbo Nature Reserve is 8.485 billion yuan, while the function of water conservation is a small fraction of ecological service function, indicating that there is great ecological value in service function of forest ecosystem in Gongbo Nature Reserve, that is, Gongbo Nature Reserve has vital ecological value.
5. Subspecies in Przewalski's gazelle Procapra przewalskii and its conservation implication
Institute of Scientific and Technical Information of China (English)
MARDAN Turghan; JIANG ZhiGang; GROVES Colin P; YANG Ji; FANG HongXia
2013-01-01
Przewalski's gazelle Procapra przewalskii is an endangered species endemic to China.A question remains about subspecific variation in this species.Skulls of Przewalski's gazelle collected from its current remnant ranges around the Qinghai Lake in combination with those collected prior to the 20th century were measured and analyzed using Hierarchical Cluster Analysis in order to clarify the question.Unexpectedly,P.p.diversicornis,extirpated from its historic range,has spread to the Qinghai Lake region where it has replaced nominotypical P.p.przewalskii and is now restricted to a few small isolated populations around the lake.We discuss the causes of this unexpected replacement.In this study,we discuss the possibility of a new form,possibly a new subspecies,in the Guide Basin,adjacent to Qinghai Lake; it is unclear whether the new form has long existed and was only discovered in recent years,or whether it evolved in recent times due to the geographical isolation and anthropogenic landscape features.The study sheds light on the processes of microevolution and subspeciation in Procapra przewalskii,and based on the findings,we propose measures for conservation strategies for Przewalski's gazelle.
6. Both Direct and Vicarious Experiences of Nature Affect Children’s Willingness to Conserve Biodiversity
Directory of Open Access Journals (Sweden)
Masashi Soga
2016-05-01
Full Text Available Children are becoming less likely to have direct contact with nature. This ongoing loss of human interactions with nature, the extinction of experience, is viewed as one of the most fundamental obstacles to addressing global environmental challenges. However, the consequences for biodiversity conservation have been examined very little. Here, we conducted a questionnaire survey of elementary schoolchildren and investigated effects of the frequency of direct (participating in nature-based activities and vicarious experiences of nature (reading books or watching TV programs about nature and talking about nature with parents or friends on their affective attitudes (individuals’ emotional feelings toward and willingness to conserve biodiversity. A total of 397 children participated in the surveys in Tokyo. Children’s affective attitudes and willingness to conserve biodiversity were positively associated with the frequency of both direct and vicarious experiences of nature. Path analysis showed that effects of direct and vicarious experiences on children’s willingness to conserve biodiversity were mediated by their affective attitudes. This study demonstrates that children who frequently experience nature are likely to develop greater emotional affinity to and support for protecting biodiversity. We suggest that children should be encouraged to experience nature and be provided with various types of these experiences.
7. Both Direct and Vicarious Experiences of Nature Affect Children’s Willingness to Conserve Biodiversity
Science.gov (United States)
Soga, Masashi; Gaston, Kevin J.; Yamaura, Yuichi; Kurisu, Kiyo; Hanaki, Keisuke
2016-01-01
Children are becoming less likely to have direct contact with nature. This ongoing loss of human interactions with nature, the extinction of experience, is viewed as one of the most fundamental obstacles to addressing global environmental challenges. However, the consequences for biodiversity conservation have been examined very little. Here, we conducted a questionnaire survey of elementary schoolchildren and investigated effects of the frequency of direct (participating in nature-based activities) and vicarious experiences of nature (reading books or watching TV programs about nature and talking about nature with parents or friends) on their affective attitudes (individuals’ emotional feelings) toward and willingness to conserve biodiversity. A total of 397 children participated in the surveys in Tokyo. Children’s affective attitudes and willingness to conserve biodiversity were positively associated with the frequency of both direct and vicarious experiences of nature. Path analysis showed that effects of direct and vicarious experiences on children’s willingness to conserve biodiversity were mediated by their affective attitudes. This study demonstrates that children who frequently experience nature are likely to develop greater emotional affinity to and support for protecting biodiversity. We suggest that children should be encouraged to experience nature and be provided with various types of these experiences. PMID:27231925
8. Framing the relationship between people and nature in the context of European conservation.
Science.gov (United States)
Linnell, John D C; Kaczensky, Petra; Wotschikowsky, Ulrich; Lescureux, Nicolas; Boitani, Luigi
2015-08-01
A key controversy in conservation is the framing of the relationship between people and nature. The extent to which the realms of nature and human culture are viewed as separate (dualistic view) or integrated is often discussed in the social sciences. To explore how this relationship is represented in the practice of conservation in Europe, we considered examples of cultural landscapes, wildlife (red deer, reindeer, horses), and protected area management. We found little support, for a dualistic worldview, where people and nature are regarded as separate in the traditional practice of conservation in Europe. The borders between nature and culture, wild and domestic, public land and private land, and between protected areas and the wider landscape were blurred and dynamic. The institutionalized (in practice and legislation) view is of an interactive mutualistic system in which humans and nature share the whole landscape. However, more dualistic ideals, such as wilderness and rewilding that are challenging established practices are expanding. In the context of modern day Europe, wilderness conservation and rewilding are not valid for the whole landscape, although it is possible to integrate some areas of low-intervention management into a wider matrix. A precondition for success is to recognize and plan for a plurality of values concerning the most valid approaches to conservation and to plan for this plurality at the landscape scale. © 2015 Society for Conservation Biology.
9. Differential use of salmon by vertebrate consumers: implications for conservation
Directory of Open Access Journals (Sweden)
Taal Levi
2015-08-01
Full Text Available Salmon and other anadromous fish are consumed by vertebrates with distinct life history strategies to capitalize on this ephemeral pulse of resource availability. Depending on the timing of salmon arrival, this resource may be in surplus to the needs of vertebrate consumers if, for instance, their populations are limited by food availability during other times of year. However, the life history of some consumers enables more efficient exploitation of these ephemeral resources. Bears can deposit fat and then hibernate to avoid winter food scarcity, and highly mobile consumers such as eagles, gulls, and other birds can migrate to access asynchronous pulses of salmon availability. We used camera traps on pink, chum, and sockeye salmon spawning grounds with various run times and stream morphologies, and on individual salmon carcasses, to discern potentially different use patterns among consumers. Wildlife use of salmon was highly heterogeneous. Ravens were the only avian consumer that fed heavily on pink salmon in small streams. Eagles and gulls did not feed on early pink salmon runs in streams, and only moderately at early sockeye runs, but were the dominant consumers at late chum salmon runs, particularly on expansive river flats. Brown bears used all salmon resources far more than other terrestrial vertebrates. Notably, black bears were not observed on salmon spawning grounds despite being the most frequently observed vertebrate on roads and trails. From a conservation and management perspective, all salmon species and stream morphologies are used extensively by bears, but salmon spawning late in the year are disproportionately important to eagles and other highly mobile species that are seasonally limited by winter food availability.
10. Redefining Secondary Forests in the Mexican Forest Code: Implications for Management, Restoration, and Conservation
Directory of Open Access Journals (Sweden)
Francisco J. Román-Dañobeytia
2014-05-01
Full Text Available The Mexican Forest Code establishes structural reference values to differentiate between secondary and old-growth forests and requires a management plan when secondary forests become old-growth and potentially harvestable forests. The implications of this regulation for forest management, restoration, and conservation were assessed in the context of the Calakmul Biosphere Reserve, which is located in the Yucatan Peninsula. The basal area and stem density thresholds currently used by the legislation to differentiate old-growth from secondary forests are 4 m2/ha and 15 trees/ha (trees with a diameter at breast height of >25 cm; however, our research indicates that these values should be increased to 20 m2/ha and 100 trees/ha, respectively. Given that a management plan is required when secondary forests become old-growth forests, many landowners avoid forest-stand development by engaging slash-and-burn agriculture or cattle grazing. We present evidence that deforestation and land degradation may prevent the natural regeneration of late-successional tree species of high ecological and economic importance. Moreover, we discuss the results of this study in the light of an ongoing debate in the Yucatan Peninsula between policy makers, non-governmental organizations (NGOs, landowners and researchers, regarding the modification of this regulation to redefine the concept of acahual (secondary forest and to facilitate forest management and restoration with valuable timber tree species.
11. NATURE CONSERVATION MOVEMENT IN THE WORLD: ITS HISTORICAL DEVELOPMENT AND PRESENT SITUATION
Directory of Open Access Journals (Sweden)
Oğuz Kurdoğlu
2007-04-01
Full Text Available Although nature conservation is a well recognized topic at present, it is not a new phenomenon. Throughout history, there are numerous examples of efforts made by governments, rulers, or individual land owners to protect certain land areas that possessed unique natural values. While many of these areas were actually isolated as game preserves for hunting, they were also designed to conserve wildlife. The establishment of Yellowstone National Park in 1972 marks the modern concept of a national park as it was designed on a very large protected natural area. Presently, one of the most efficient ways for nature protection is “area conservation approach” that many organizations have been developing various systems and categories about. Unfortunately, in spite of such improvements and the extension of the protected area network, many of these areas are not properly protected and/or managed in some countries. This study summarizes the historical evolution of nature conservation systems and strategies in the world with the related international legislative aspects as well. As it stated in this paper, USA and Europa have a well known history on nature conservation and show great concern in respect to participating to the international convention and arrangements.
12. Structure, function and management of semi-natural habitats for conservation biological control
NARCIS (Netherlands)
Holland, John M.; Bianchi, Felix J.J.A.; Entling, Martin H.; Moonen, Anna Camilla; Smith, Barbara M.; Jeanneret, Philippe
2016-01-01
Different semi-natural habitats occur on farmland, and it is the vegetation's traits and structure that subsequently determine their ability to support natural enemies and their associated contribution to conservation biocontrol. New habitats can be created and existing ones improved with agri-en
13. Nature conservation and tourism development in the Dutch Wadden Sea region: a common future?
NARCIS (Netherlands)
Revier, Hans
2013-01-01
This chapter is about the development of tourism in the Dutch Wadden Sea Region in combination with nature conservation. The main question is whether they have a common future. There are some future points stated: - Nature and landscape of the Wadden Sea are the main pull factors for the tourism de
14. Structure, function and management of semi-natural habitats for conservation biological control
NARCIS (Netherlands)
Holland, John M.; Bianchi, Felix J.J.A.; Entling, Martin H.; Moonen, Anna Camilla; Smith, Barbara M.; Jeanneret, Philippe
2016-01-01
Different semi-natural habitats occur on farmland, and it is the vegetation's traits and structure that subsequently determine their ability to support natural enemies and their associated contribution to conservation biocontrol. New habitats can be created and existing ones improved with
15. Nature conservation and tourism development in the Dutch Wadden Sea region: a common future?
NARCIS (Netherlands)
Hans Revier
2013-01-01
This chapter is about the development of tourism in the Dutch Wadden Sea Region in combination with nature conservation. The main question is whether they have a common future. There are some future points stated: - Nature and landscape of the Wadden Sea are the main pull factors for the tourism de
16. Formative Life Experiences and the Recruitment of Natural Resource Conservation Professionals
Science.gov (United States)
Jackson, Marc
2013-01-01
Recruiting young people to serve as future leaders is a major concern for many organizations involved in natural resource conservation. One of the primary reasons for this concern is that youth are becoming less connected to the natural world because of the synergistic effects of urbanization, electronic media, and reduced opportunities to explore…
17. Natural forest conservation hierarchical program with neural network
Institute of Scientific and Technical Information of China (English)
LUO Chuanwen; LI Jihong
2006-01-01
In this paper,the implementing steps of a natural forest protection program grading (NFPPG) with neural network (NN) were summarized and the concepts of program illustration,patch sign unification and regression,and inclining factor were set forth.Employing Arc/Info GIS,the tree species diversity and rarity,disturbance degree,protection of channel system,and classification management in the Maoershan National Forest Park were described,and used as the input factors of NN.The relationships between NFPPG and above factors were also analyzed.By artificially determining training samples,the NFPPG of Moershan National Forest Park was created.Tested with all patches in the park,the generalization of NFPPG was satisfied.NFPPG took both the classification management and the protection of forest community types into account,as well as the ecological environment.The excitation function of NFPPG was not seriously saturated,indicating the leading effect of the inclining factor on the network optimization.
18. What the Inbred Scandinavian Wolf Population Tells Us about the Nature of Conservation.
Directory of Open Access Journals (Sweden)
Jannikke Räikkönen
Full Text Available The genetic aspects of population health are critical, but frequently difficult to assess. Of concern has been the genetic constitution of Scandinavian wolves (Canis lupus, which represent an important case in conservation. We examined the incidence of different congenital anomalies for 171 Scandinavian wolves, including the immigrant founder female, born during a 32-year period between 1978 and 2010. The incidence of anomalies rose from 13% to 40% throughout the 32-year study period. Our ability to detect this increase was likely facilitated by having considered multiple kinds of anomaly. Many of the found anomalies are likely associated with inbreeding or some form of genetic deterioration. These observations have implications for understanding the conservation needs of Scandinavian wolves. Moreover, these observations and the history of managing Scandinavian wolves focus attention on a broader question, whether conservation is merely about avoiding extinction of remnant populations, or whether conservation also entails maintaining genetic aspects of population health.
19. The hydrologic implications of alternative prioritizations of landscape-scale geographically isolated wetlands conservation
Science.gov (United States)
Evenson, G. R.; Golden, H. E.; Lane, C.; Mclaughlin, D. L.; D'Amico, E.
2016-12-01
Geographically isolated wetlands (GIWs), defined as upland embedded wetlands, provide an array of ecosystem goods and services. Wetland conservation efforts aim to protect GIWs in the face of continued threats from anthropogenic activities. Given limited conservation resources, there is a critical need for methods capable of evaluating the watershed-scale hydrologic implications of alternative approaches to GIW conservation. Further, there is a need for methods that quantify the watershed-scale aggregate effects of GIWs to determine their regulatory status within the United States. We applied the Soil and Water Assessment Tool (SWAT), a popular watershed-scale hydrologic model, to represent the 1,700 km2 Pipestem Creek watershed in North Dakota, USA. We modified the model to incorporate an improved representation of GIW hydrologic processes via hydrologic response unit (HRU) redefinition and modifications to the model source code. We then used the model to evaluate the hydrologic effects of alternative approaches to GIW conservation prioritization by simulating the destruction/removal of GIWs by sub-classes defined by their relative position within the simulated fill-spill GIW network and their surface area characteristics. We evaluated the alternative conservation approaches as impacting (1) simulated streamflow at the Pipestem Creek watershed outlet; (2) simulated water-levels within the GIWs; and (3) simulated hydrologic connections between the GIWs. Our approach to modifying SWAT and evaluating alternative GIW conservation strategies may be replicated in different watersheds and physiographic regions to aid the development of GIW conservation priorities.
20. Identifying potential indicators of conservation value using natural heritage occurrence data.
Science.gov (United States)
Pearman, Peter B; Penskar, Michael R; Schools, Edward H; Enander, Helen D
2006-02-01
Conservation planning based on the occurrence of rare species has been criticized as being too limited in scope to conserve biodiversity as a whole. Conversely, planning based on indicator taxa may lack sufficient focus to conserve those species in greatest need of conservation. An alternative approach is to identify a variety of species at risk that are associated with areas of conservation value, which is defined based on species-independent characteristics. We identified potential indicators of conservation value using occurrence data on species at risk and independent information on conservation value that incorporated indices of ecosystem integrity. We propose a taxonomically diverse group of indicator species that are strongly associated with areas of exceptional ecosystem integrity, to serve as a focus for further research and in planning for biodiversity conservation. We identify potential indicator species by defining a null model in which species at risk are equally associated with areas of high ecosystem integrity, then by conducting randomization tests to identify noncompliant species in the state of Michigan, USA. Areas of high ecosystem integrity are selected using criteria to flag (1) secure biotic communities with structural integrity and few exotic species, (2) natural areas subjected to expert review, (3) contiguous relict areas of forest interior, (4) contiguous areas of unmodified wetland, and (5) all these areas combined. We determine the spatial occurrence of species at risk using data from Michigan's statewide Natural Heritage database. The potential indicators include plants, insects, and birds. Their species identity and distribution of occurrences varies with the five scenarios, and together the species broadly cover the entire state. These species at risk, many of which occur throughout the Great Lakes region, may be used to identify additional areas potentially high in conservation value and to monitor their conservation. The ecological
1. The alignment of agricultural and nature conservation policies in the European Union.
Science.gov (United States)
Hodge, Ian; Hauck, Jennifer; Bonn, Aletta
2015-08-01
Europe is a region of relatively high population density and productive agriculture subject to substantial government intervention under the Common Agricultural Policy (CAP). Many habitats and species of high conservation interest have been created by the maintenance of agricultural practices over long periods. These practices are often no longer profitable, and nature conservation initiatives require government support to cover the cost for them to be continued. The CAP has been reformed both to reduce production of agricultural commodities at costs in excess of world prices and to establish incentives for landholders to adopt voluntary conservation measures. A separate nature conservation policy has established an extensive series of protected sites (Natura 2000) that has, as yet, failed to halt the loss of biodiversity. Additional broader scale approaches have been advocated for conservation in the wider landscape matrix, including the alignment of agricultural and nature conservation policies, which remains a challenge. Possibilities for alignment include further shifting of funds from general support for farmers toward targeted payments for biodiversity goals at larger scales and adoption of an ecosystem approach. The European response to the competing demands for land resources may offer lessons globally as demands on rural land increase.
2. Management Philosophy and Practices of Habitat Conservation for Jiuzhaigou Nature Reserve, Sichuan, China
Institute of Scientific and Technical Information of China (English)
FANG Yi-ping; ZENG Yong; LI Shi-ming
2005-01-01
Starting from the pressure on habitat of Jiuzhaigou Nature Reserve brought about by traveling activity, this paper puts forward such philosophy of community co-management of conservation-based tourism development for Jiuzhaigou Nature Reserve. According to this philosophy, emphasis is laid on the analysis of the mission of habitat protection, functional division, habitat maintenance, community construction, scientific study and management organization system. The study shows that the close relation and significance of rights and interests shared between nature reserve and residents in community, as well as the value of community co-management philosophy of conservation-based tourism development in sustainable management of nature reserve, have set an exemplary example for other nature reserves.
3. Natural Fostering in Fritillaria cirrhosa: Integrating herbal medicine production with biodiversity conservation
Directory of Open Access Journals (Sweden)
Xiwen Li
2012-02-01
Full Text Available Protected areas are generally regarded as a power tool to conserve biodiversity. Nonetheless, few protected areas could address three crucial problems simultaneously, namely funding, public participation and rural living. Here, we introduced a new protective approach, Natural Fostering, which integrated herbal medicine production with community conservation. The principles of Natural Fostering adopted species–species interaction at community level. Most effective chemical components of herbal medicine are derived from such interaction. Fritillaria cirrhosa was selected as an economic botany, one of herbal medicines, to carry out Natural Fostering. Community habitats, herbal medicine production, funding and income of local family were investigated to verify the feasibility of Natural Fostering for biodiversity. We found the density of plant populations and the annual average personal income of rural people increased. F. cirrhosa production could provide sufficient funds for sustainable conservation. Local people gradually changed their life style of wild collection and overgrazing, instead of herbal medicine production. The fostering area set up a good sustainable economic cycle. Natural Fostering can be presented as an effective and pragmatic way to conserve biological diversity and sustainable utilization of traditional medicinal resources.
4. The potential natural vegetation of eastern Africa distribution, conservation and future changes
DEFF Research Database (Denmark)
van Breugel, Paulo
Species and ecosystems are increasingly threatened by the human activities, while climate change projections show that eastern Africa may face considerable changes in temperature and rainfall regimes. These changes pose huge challenges for the prioritization and implementation of conservation...... and sustainable management of the natural environment. There is therefore an urgent need for information that allow us to assess the current status of the region’s natural environment and to predict how this may change under future climates. This thesis aims to improve our knowledge on natural vegetation...... distribution in eastern African, examine how this may change under future climates, and how this can be used to identify conservation priorities in the region. Chapter 1 presents a brief overview of the concept of the potential natural vegetation (PNV), synthesizes the general findings and discusses future...
5. The Realities of Community Based Natural Resource Management and Biodiversity Conservation in Sub-Saharan Africa
Directory of Open Access Journals (Sweden)
Brian Kevin Reilly
2009-09-01
Full Text Available This is an historic overview of conservation in Sub-Saharan Africa from pre-colonial times through the present. It demonstrates that Africans practiced conservation that was ignored by the colonial powers. The colonial market economy combined with the human and livestock population explosion of the 21st century are the major factors contributing to the demise of wildlife and critical habitat. Unique insight is provided into the economics of a representative safari company, something that has not been readily available to Community Based Natural Resources Management (CBNRM practitioners. Modern attempts at sharing benefits from conservation with rural communities will fail due to the low rural resource to population ratio regardless of the model, combined with the uneven distribution of profits from safari hunting that drives most CBNRM programs, unless these ratios are changed. Low household incomes from CBNRM are unlikely to change attitudes of rural dwellers towards Western approaches to conservation. Communities must sustainably manage their natural areas as "green factories" for the multitude of natural resources they contain as a means of maximizing employment and thus household incomes, as well as meeting the often overlooked socio-cultural ties to wildlife and other natural resources, which may be as important as direct material benefits in assuring conservation of wildlife and its habitat. For CBNRM to be successful in the long-term, full devolution of ownership over land and natural resources must take place. In addition, as a means of relieving pressure on the rural resource base, this will require an urbanization process that creates a middleclass, as opposed to the current slums that form the majority of Africa‘s cities, through industrialization that transforms the unique natural resources of the subcontinent (e.g., strategic minerals, petroleum, wildlife, hardwoods, fisheries, wild medicines, agricultural products, etc. in Africa.
6. "The man, the administration and the counter-discourse”: An analysis of the sudden turn in Dutch nature conservation policy
NARCIS (Netherlands)
Buijs, A.E.; Mattijssen, T.; Arts, B.J.M.
2014-01-01
The Netherlands were at the forefront of European nature conservation policy until recently. For years, a stable ‘social contract’ around Dutch nature conservation existed. To the surprise of many, this stability suddenly disappeared and Dutch nature policy has taken a dramatic shift with changing d
7. Conservation of the Sapsaree (Canis familiaris), a Korean Natural Monument, using somatic cell nuclear transfer.
Science.gov (United States)
Jang, Goo; Hong, SoGun; Kang, JungTaek; Park, JungEun; Oh, HyunJu; Park, ChanKyu; Ha, JiHong; Kim, DaeYong; Kim, MinKyu; Lee, ByeongChun
2009-09-01
A recent emerging technology, somatic cell nuclear transfer (SCNT), has been considered for conserving threatened or endangered species. Sapsaree is a native breed in Korea and has been designated as a Natural Monument. The aim of this study was to produce a Sapsaree by SCNT for breed conservation. Donor fibroblasts from a 9-year-old male Sapsaree were placed into the perivitelline spaces of enucleated in vivo matured oocytes and fused electrically. A total of 309 cloned embryos were transferred into the oviducts of 15 naturally synchronized recipients. Two recipients were diagnosed as pregnant, and each delivered one cloned puppy, both of which weighed 530 g. Overall, this study demonstrated that an endangered canine breed can be conserved by SCNT.
8. Comparative analysis reveals conserved protein phosphorylation networks implicated in multiple diseases
DEFF Research Database (Denmark)
Tan, Chris Soon Heng; Bodenmiller, Bernd; Pasculescu, Adrian
2009-01-01
approximately 600 million years of evolution and hence are likely to be involved in fundamental cellular processes. This sequence-alignment analysis suggested that many phosphorylation sites evolve rapidly and therefore do not display strong evolutionary conservation in terms of sequence position in distantly...... related organisms. Thus, we devised a network-alignment approach to reconstruct conserved kinase-substrate networks, which identified 778 phosphorylation events in 698 human proteins. Both methods identified proteins tightly regulated by phosphorylation as well as signal integration hubs, and both types...... of phosphoproteins were enriched in proteins encoded by disease-associated genes. We analyzed the cellular functions and structural relationships for these conserved signaling events, noting the incomplete nature of current phosphoproteomes. Assessing phosphorylation conservation at both site and network levels...
9. Nature conservation in Central and Eastern Europe with a special emphasis on the Carpathian Mountains
Energy Technology Data Exchange (ETDEWEB)
Oszlanyi, Julius; Grodzinska, Krystyna; Badea, Ovidiu; Shparyk, Yuriy
2004-07-01
The natural environment of the Carpathian Mountains is one of the richest in Europe in terms of species richness and ecological value. In general, these mountains are well preserved and constitute an important part of Europe's nature resources. The Carpathian area, although divided by political and ethnic frontiers, provides an excellent example of the possibility of protection and conservation of natural and cultural heritage. Natural or seminatural forest ecosystems are the most valuable ecosystems together with man-made meadows and pastures. It is expected that the formerly diverse approaches to nature protection will become unified as the Carpathian countries are incorporated into the European Union. In this paper the various forms of nature protection in the individual Carpathian countries (Czech Republic, Slovakia, Poland, Ukraine and Romania) are described. - Current status of nature protection in countries of the Carpathian Region is described.
10. Semi-natural habitats support biological control, pollination and soil conservation in Europe. A review
NARCIS (Netherlands)
Holland, John M.; Douma, Jacob C.; Crowley, Liam; James, Laura; Kor, Laura; Stevenson, David R.W.; Smith, Barbara M.
2017-01-01
Semi-natural habitats are integral to most agricultural areas and have the potential to support ecosystem services, especially biological control and pollination by supplying resources for the invertebrates providing these services and for soil conservation by preventing erosion and run-off. Some
11. Shortleaf pine natural community restoration on Peck Ranch Conservation Area in the Missouri Ozarks
Science.gov (United States)
John G. Tuttle; Kim J. Houf
2007-01-01
Oak decline has become a significantly increasing problem on Peck Ranch Conservation Area over the last several years. Most of the oak decline problems exist on past shortleaf pine sites. To address this issue, the area managers wrote a natural community restoration plan for 2,233 acres located on the Current-Eleven Point Oak-Pine Woodland Dissected Plain land type...
12. Farmers' Cynicism toward Nature and Distrust of the Government: Where Does that Leave Conservation Buffer Programs?
Science.gov (United States)
Gronewold, Katherine L.; Burnett, Ann; Meister, Mark
2012-01-01
Farmers are commonly regarded as stewards of the land. Farmers have, however, become cynical toward nature (Meister, Hest, & Burnett, 2009) and distrustful of the government (Cantrill, 2003). This study examines whether or not that cynicism and distrust is reflected in U.S. farmers' opinions of and future participation in conservation buffer…
13. Survival strategies of people in a Sri Lankan wetland : livelihood, health and nature conservation in Muthurajawela
NARCIS (Netherlands)
Hoogvorst, A.
2003-01-01
Key words: Anthropology, emic, environment, etic, gender, health, livelihoods, Muthurajawela, nature-conservation, survival strategies, Sri Lanka, wetland.The objective of this study was to contribute to a better understanding of how poor people living in a sensitive wetland ecosystem maint
14. The tension between nature conservation and economic valuation of ecosystem services
NARCIS (Netherlands)
2016-01-01
Economic valuation of ecosystem services is a popular yet troubled approach in modern nature conservation. It's effectiveness remains unknown while a lot of criticism is noted in the literature about potential consequences of this approach. This thesis first clarifies the various discourses extant a
15. Survival strategies of people in a Sri Lankan wetland : livelihood, health and nature conservation in Muthurajawela
NARCIS (Netherlands)
Hoogvorst, A.
2003-01-01
Key words: Anthropology, emic, environment, etic, gender, health, livelihoods, Muthurajawela, nature-conservation, survival strategies, Sri Lanka, wetland.The objective of this study was to contribute to a better understanding of how poor people living in a sensitive wetland ecosystem
16. The tension between nature conservation and economic valuation of ecosystem services
NARCIS (Netherlands)
2016-01-01
Economic valuation of ecosystem services is a popular yet troubled approach in modern nature conservation. It's effectiveness remains unknown while a lot of criticism is noted in the literature about potential consequences of this approach. This thesis first clarifies the various discourses extant
17. Farmers' Cynicism toward Nature and Distrust of the Government: Where Does that Leave Conservation Buffer Programs?
Science.gov (United States)
Gronewold, Katherine L.; Burnett, Ann; Meister, Mark
2012-01-01
Farmers are commonly regarded as stewards of the land. Farmers have, however, become cynical toward nature (Meister, Hest, & Burnett, 2009) and distrustful of the government (Cantrill, 2003). This study examines whether or not that cynicism and distrust is reflected in U.S. farmers' opinions of and future participation in conservation buffer…
18. The implementation of international nature conservation agreements in Europe: the case of the Netherlands
NARCIS (Netherlands)
Bennett, G.; Ligthart, S.S.H.
2001-01-01
Nature conservation policy in European countries is increasingly determined by the requirements of a wide range of international agreements. The most important are two EU directives (the Birds Directive and the Habitats Directive) and four conventions(the Ramsar Convention, the Bern Convention, the
19. Systematizing Scientific Knowledge in Sustainable Tourism, Poverty Reduction and Nature Conservation
NARCIS (Netherlands)
Tassone, V.C.
2008-01-01
The state of the art of tourism research, second chapter. A detailed maping by Tassone of the development of research in the field of tourism, nature conservation and poverty reduction. She provides an indication of the direction of past scientific research work in this field.
20. Evaluating the Household Level Outcomes of Community Based Natural Resource Management: the Tchuma Tchato Project and Kwandu Conservancy
Directory of Open Access Journals (Sweden)
Helen Suich
2013-12-01
Full Text Available Community based natural resource management (CBNRM programs aim to link the achievement of conservation objectives with those of rural development and poverty alleviation. However, after more than a decade of implementation in southern Africa, there is remarkably little rigorous analysis of their achievements with respect to these goals. An evaluation of two CBNRM interventions, the Tchuma Tchato Project in Mozambique and the Kwandu Conservancy in Namibia, measured the impacts at the household level using multidimensional poverty indices. The analysis found no positive impacts on the multiple dimensions of poverty arising from the Tchuma Tchato initiative in Mozambique. In Kwandu Conservancy in Namibia, positive impacts were felt only on household financial capital on a disappointingly narrow scale. These results have important implications for policy makers and program designers and demonstrate the necessity of developing targeted strategies if poverty alleviation outcomes are to be achieved. Further, if the assumption that the provision of incentives is key to encouraging and maintaining participation in CBNRM is correct, the delivery of appropriate benefits that have a sufficient impact at the household level will be crucial for the long run sustainability of these initiatives.
1. Land Use Change Around Nature Reserves: Implications for Sustaining Biodiversity
Science.gov (United States)
Hansen, A. J.; Defries, R.; Curran, L.; Liu, J.; Reid, R.; Turner, B.
2004-12-01
The effects of land use change outside of reserves on biodiversity within reserves is not well studied. This paper draws on research from Yellowstone, East Africa, Yucatan, Borneo, and Wolong, China to examine land use effects on nature reserves. Objectives are: quantify rates of change in land use around reserves; examine consequences for biodiversity within the context of specific ecological mechanisms; and draw implications for regional management. Within each of the study regions, semi-natural habitats around nature reserves have been converted to agricultural, rural residential, or urban land uses. Rates vary from 0.2-0.4 %/yr in Yucatan, to 9.5 %/yr in Borneo. Such land use changes may be important because nature reserves are often parts of larger ecosystems that are defined by flows in energy, materials, and organisms. Land use outside of reserves may disrupt these flows and alter biodiversity within reserves. Ecological mechanisms that connect biodiversity to these land use changes include habitat size, ecological flows, crucial habitats, and edge effects. For example, the effective size of the East African study area has been reduced by 45% by human activities. Based on the species area relationship, this reduction in habitat area will lead to a loss of 14% of bird and mammal species. A major conclusion is that the viability of nature reserves can best be ensured by managing them in the context of the surrounding region. Knowledge of the ecological mechanisms by which land use influences nature reserves provides design criteria for this regional management.
2. Welfare implications of tropical forest conservation: the case of Ruteng Park
Science.gov (United States)
David Butry; Subhrendu Pattanayak
2000-01-01
In 1993, the Indonesian government established the Ruteng Nature Recreation Park in western Flores. Subsequently, the government banned all timber extraction in and around the park's sub-tropical forest to promote biodiversity and watershed protection. This study quantitatively examines the role that tropical forest conservation has on the development of the local...
3. Perceptions and attitudes of land managers in multi-tenure reserve networks and the implications for conservation.
Science.gov (United States)
Fitzsimons, James A; Wescott, Geoff
2007-07-01
Multi-tenure reserve networks aim to connect areas managed for biodiversity conservation across public and private land and address the impacts of fragmentation on both biotic and social systems. The operation and function of Australian multi-tenure reserve networks as perceived by their land managers was investigated. Overall, the conservation of natural assets was the most frequently reported primary reason for involvement in a network. The perceived aims of the respective networks largely reflected the response identified for involvement and management. Over 88% of managers considered their involvement in multi-tenure reserve networks to be a positive or very positive experience. A lack of resources and time for management were considered major limitations of these networks. The majority (80%) of private land managers within networks were willing to be included in a national reserve system of conservation lands. As the Australian National Reserve System currently incorporates mostly public land, these findings have important and potentially positive implications for a greater role for protected private land.
4. Estimating landholders' probability of participating in a stewardship program, and the implications for spatial conservation priorities.
Directory of Open Access Journals (Sweden)
Full Text Available The need to integrate social and economic factors into conservation planning has become a focus of academic discussions and has important practical implications for the implementation of conservation areas, both private and public. We conducted a survey in the Daly Catchment, Northern Territory, to inform the design and implementation of a stewardship payment program. We used a choice model to estimate the likely level of participation in two legal arrangements--conservation covenants and management agreements--based on payment level and proportion of properties required to be managed. We then spatially predicted landholders' probability of participating at the resolution of individual properties and incorporated these predictions into conservation planning software to examine the potential for the stewardship program to meet conservation objectives. We found that the properties that were least costly, per unit area, to manage were also the least likely to participate. This highlights a tension between planning for a cost-effective program and planning for a program that targets properties with the highest probability of participation.
5. Assessment of energy and natural resources conservation in office buildings using TOBUS
Energy Technology Data Exchange (ETDEWEB)
Balaras, C.A.; Droutsa, K.; Argiriou, A.A. [Group Energy Conservation, Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, Hellas (Greece); Wittchen, K.B. [Danish Building Research Institute, Horsholm (Denmark)
2001-07-01
The potential for optimum energy use and conservation of natural resources in representative southern and northern European office buildings is evaluated using the new European TOBUS methodology and software for office building refurbishment. Various scenarios are being accessed for energy and water conservation in office buildings. The proposed retrofit actions focus in the areas of space heating and cooling, artificial and natural lighting, service hot water, office equipment, elevators and sanitary water. The resulting conservation and related costs are taken into account in order to help the auditor classify the retrofit actions for an audited building. The TOBUS methodology and tools have been implemented to study four Hellenic office buildings and two from Denmark in order to demonstrate the applicability of the overall approach. Energy conservation in Hellenic and Danish buildings range for space heating from 5 to 71 and 0.5 to 6%, for space cooling from 1 to 38 and 4 to 20%, for artificial lighting from 40 to 53 and 26 to 62%, for office equipment from 13 to 62 and 13 to 87% and for elevators at 35 and 23%, respectively. Sanitary water conservation can reach 74% in all audited buildings. (author)
6. Conservation implications of brown hyaena (Parahyaena brunnea population densities and distribution across landscapes in Botswana
Directory of Open Access Journals (Sweden)
Christiaan W. Winterbach
2017-05-01
Full Text Available The brown hyaena (Parahyaena brunnea is endemic to southern Africa. The largest population of this near-threatened species occurs in Botswana, but limited data were available to assess distribution and density. Our objectives were to use a stratified approach to collate available data and to collect more data to assess brown hyaena distribution and density across land uses in Botswana. We conducted surveys using track counts, camera traps and questionnaires and collated our results and available data to estimate the brown hyaena population based on the stratification of Botswana for large carnivores. Brown hyaenas occur over 533 050 km² (92% of Botswana. Our density estimates ranged from 0 brown hyaenas/100 km² in strata of northern Botswana to 2.94 (2.16–3.71 brown hyaenas/100 km² in the southern stratum of the Central Kalahari Game Reserve. We made assumptions regarding densities in strata that lacked data, using the best references available. We estimated the brown hyaena population in Botswana as 4642 (3133–5993 animals, with 6.8% of the population in the Northern Conservation Zone, 73.1% in the Southern Conservation Zone, 2.0% in the smaller conservation zones and 18.1% in the agricultural zones. The similar densities of brown hyaenas in the Central Kalahari Game Reserve and the Ghanzi farms highlight the potential of agricultural areas in Botswana to conserve this species. The conservation of brown hyaenas in the agricultural landscape of Botswana is critical for the long-term conservation of the species; these areas provide important links between populations in South Africa, Namibia and Zimbabwe.Conservation implications: Botswana contains the core of the brown hyaena population in southern Africa, and conflict mitigation on agricultural land is crucial to maintaining connectivity among the range countries.
7. Nature conservation in Central and Eastern Europe with a special emphasis on the Carpathian Mountains.
Science.gov (United States)
Oszlányi, Július; Grodzińska, Krystyna; Badea, Ovidiu; Shparyk, Yuriy
2004-07-01
The natural environment of the Carpathian Mountains is one of the richest in Europe in terms of species richness and ecological value. In general, these mountains are well preserved and constitute an important part of Europe's nature resources. The Carpathian area, although divided by political and ethnic frontiers, provides an excellent example of the possibility of protection and conservation of natural and cultural heritage. Natural or seminatural forest ecosystems are the most valuable ecosystems together with man-made meadows and pastures. It is expected that the formerly diverse approaches to nature protection will become unified as the Carpathian countries are incorporated into the European Union. In this paper the various forms of nature protection in the individual Carpathian countries (Czech Republic, Slovakia, Poland, Ukraine and Romania) are described.
8. Natural resource economic implications of geothermal area use
Energy Technology Data Exchange (ETDEWEB)
Darby, d' E Charles
1993-01-28
Large-scale use of geothermal energy is likely to result in depletion of natural resources that support both biodiversity and other human uses. Most of the problems could be averted with competent planning and adherence to agreed conditions, but they commonly develop because they are not perceived to be directly geothermal in origin and hence are not taken into account adequately. Some of the implications of such issues are discussed below, with particular reference to countries where all or most resources are held under traditional principals of custom ownership.
9. Yet another empty forest: considering the conservation value of a recently established tropical nature reserve.
Directory of Open Access Journals (Sweden)
Rachakonda Sreekar
Full Text Available The primary approach used to conserve tropical biodiversity is in the establishment of protected areas. However, many tropical nature reserves are performing poorly and interventions in the broader landscape may be essential for conserving biodiversity both within reserves and at large. Between October 2010 and 2012, we conducted bird surveys in and around a recently established nature reserve in Xishuangbanna, China. We constructed a checklist of observed species, previously recorded species, and species inferred to have occurred in the area from their distributions and habitat requirements. In addition, we assessed variation in community composition and habitat specificity at a landscape-scale. Despite the fact that the landscape supports a large area of natural forest habitat (~50,000 ha, we estimate that >40% of the bird fauna has been extirpated and abundant evidence suggests hunting is the primary cause. A large proportion (52% of the bigger birds (>20 cm were extirpated and for large birds there was a U-shaped relationship between habitat breadth and extirpation probability. Habitat specificity was low and bird communities were dominated by widespread species of limited conservation concern. We question whether extending tropical protected area networks will deliver desired conservation gains, unless much greater effort is channeled into addressing the hunting problem both within existing protected areas and in the broader landscape.
10. Yet another empty forest: considering the conservation value of a recently established tropical nature reserve.
Science.gov (United States)
Sreekar, Rachakonda; Zhang, Kai; Xu, Jianchu; Harrison, Rhett D
2015-01-01
The primary approach used to conserve tropical biodiversity is in the establishment of protected areas. However, many tropical nature reserves are performing poorly and interventions in the broader landscape may be essential for conserving biodiversity both within reserves and at large. Between October 2010 and 2012, we conducted bird surveys in and around a recently established nature reserve in Xishuangbanna, China. We constructed a checklist of observed species, previously recorded species, and species inferred to have occurred in the area from their distributions and habitat requirements. In addition, we assessed variation in community composition and habitat specificity at a landscape-scale. Despite the fact that the landscape supports a large area of natural forest habitat (~50,000 ha), we estimate that >40% of the bird fauna has been extirpated and abundant evidence suggests hunting is the primary cause. A large proportion (52%) of the bigger birds (>20 cm) were extirpated and for large birds there was a U-shaped relationship between habitat breadth and extirpation probability. Habitat specificity was low and bird communities were dominated by widespread species of limited conservation concern. We question whether extending tropical protected area networks will deliver desired conservation gains, unless much greater effort is channeled into addressing the hunting problem both within existing protected areas and in the broader landscape.
11. First records of the reef manta ray Manta alfredi in the Bohol Sea, Philippines, and its implication for conservation
Directory of Open Access Journals (Sweden)
Joshua Maniriniaina Rambahiniarison
2016-12-01
Full Text Available We report the occurrence of the reef manta ray Manta alfredi Krefft 1868 in the Bohol Sea, Philippines, based on photographic evidence from boat-based surveys and a fishery specimen. Despite previous anecdotal reports from the diving industry and over a century of extensive targeted fisheries for mobulid rays in the Philippines, it was not until recently that the species was first confirmed in the country at the Tubbataha Reefs Natural Park, Palawan. Our results confirm the presence of M. alfredi in the Visayas region of the Philippines, extending the current range for the species from the Sulu Sea over 600 km eastwards. Its presence in a region with an active mobulid fishery has important implications for the conservation and management of M. alfredi in the country. We highlight the need to understand the distribution of M. alfredi in the region and make management recommendations based on the present study.
12. Landscape metrics as a tool for evaluating scenarios for flood prevention and nature conservation
Directory of Open Access Journals (Sweden)
S. Bianchin
2011-05-01
Full Text Available Within the framework of the project „Flood Prevention and Nature Conservation in the Weisseritz area“ („HochNatur“, a method including landscape metrics was developed and applied to assess and to compare different land use scenarios with regard to flood prevention and nature conservation. For the analysis, two sub-catchments strongly differing in land use within the Weisseritz catchment (Eastern Erzgebirge, Saxony, Germany were selected. The first step of the evaluation procedure was a biotope assessment using three assessment criteria (naturalness, substitutability, rareness / endangerment. However, the biotope assessment did not yield any information about spatial distribution or the structural composition of the landscape. Therefore, landscape metrics were applied to analyse the structural and biotope type diversity at the landscape scale. Different landscape metrics (Shannon/Weaver diversity index, mean patch size index, Interdispersion/Juxtaposition index and a weighting system were used to compare the different land use scenarios and the current state. The analysed catchment areas differ substantially in terms of their current state and potential measures regarding flood prevention and nature conservation depending on the location and distribution of biotope types. It was demonstrated that this method can be used for small catchment areas regardless of their land use for assessing, analysing and comparing different land use scenarios for a specific area.
13. Digital innovation through partnership between nature conservation organisations and academia: a qualitative impact assessment.
Science.gov (United States)
Galán-Díaz, Carlos; Edwards, Peter; Nelson, John D; van der Wal, René
2015-11-01
Nature conservation organisations increasingly turn to new digital technologies to help deliver conservation objectives. This has led to collaborative forms of working with academia to spearhead digital innovation. Through in-depth interviews with three UK research-council-funded case studies, we show that by working with academics conservation organisations can receive positive and negative impacts, some of which cut across their operations. Positive impacts include new ways of engaging with audiences, improved data workflows, financial benefits, capacity building and the necessary digital infrastructure to help them influence policy. Negative impacts include the time and resources required to learn new skills and sustain new technologies, managing different organisational objectives and shifts in working practices as a result of the new technologies. Most importantly, collaboration with academics was shown to bring the opportunity of a profound change in perspectives on technologies with benefits to the partner organisations and individuals therein.
14. Primate seed dispersers as umbrella species: a case study from Kibale National Park, Uganda, with implications for Afrotropical forest conservation.
Science.gov (United States)
Lambert, Joanna E
2011-01-01
Almost half of the world's extant primate species are of conservation concern [IUCN, International Union for the Conservation of Nature Red List of Threatened Species, 2008]. Primates are also effective seed dispersers. The implications of and interactions between these two facts are increasingly understood, and data demonstrating the consequences of losing primates for forest ecology are now available from throughout the tropics. However, a reality is that not all species-and the mutualisms among them-can be protected. Conservation managers must make difficult decisions and use shortcuts in the implementation of conservation tactics. Using taxa as "umbrellas" is one such shortcut, although a lack of an operational definition of what an umbrella species is and how to choose one has made implementing this tactic difficult. In this study, I discuss primates as umbrellas by defining a selection index in terms of richness/co-occurrence, rarity, and sensitivity to anthropogenic disturbance. I evaluate the anthropoid assemblage of Kibale National Park, Uganda, in light of the selection index and determine that Cercopithecus is the genus best fitting the criteria for umbrella status. I then evaluate the functional significance-in terms of seed dispersal-of using Cercopithecus monkeys (guenons) as umbrellas. Results from 1,047 hr of observation of focal fruiting trees in Kibale indicate that Cercopithecus ascanius was the most commonly observed frugivore visitor (July 2001-June 2002). These data corroborate earlier data collected in Kibale demonstrating that guenons are highly effective seed dispersers. Patterns of richness/co-occurrence, rarity, and sensitivity observed in Kibale are reflected in Afrotropical forests more generally, with the genus Cercopithecus tending to exhibit greatest richness/co-occurrence with taxonomically similar species, to be neither extremely rare nor ubiquitous, and also to be moderately sensitive to human disturbance. Moreover, in all
15. Natural History of Rotator Cuff Disease and Implications on Management
Science.gov (United States)
Hsu, Jason
2015-01-01
Degenerative rotator cuff disease is commonly associated with ageing and is often asymptomatic. The factors related to tear progression and pain development are just now being defined through longitudinal natural history studies. The majority of studies that follow conservatively treated painful cuff tears or asymptomatic tears that are monitored at regular intervals show slow progression of tear enlargement and muscle degeneration over time. These studies have highlighted greater risks for disease progression for certain variables, such as the presence of a full-thickness tear and involvement of the anterior aspect supraspinatus tendon. Coupling the knowledge of the natural history of degenerative cuff tear progression with variables associated with greater likelihood of successful tendon healing following surgery will allow better refinement of surgical indications for rotator cuff disease. In addition, natural history studies may better define the risks of nonoperative treatment over time. This article will review pertinent literature regarding degenerative rotator cuff disease with emphasis on variables important to defining appropriate initial treatments and refining surgical indications. PMID:26726288
16. Making the Most of World Natural Heritage—Linking Conservation and Sustainable Regional Development?
Directory of Open Access Journals (Sweden)
2016-03-01
Full Text Available Today, more than 1000 World Heritage (WH sites are inscribed on UNESCO’s list, 228 of which are natural and mixed heritage sites. Once focused primarily on conservation, World Natural Heritage (WNH sites are increasingly seen as promoters of sustainable regional development. Sustainability-oriented regions, it is assumed, are safeguards for conservation and positively influence local conservation goals. Within UNESCO, discussions regarding the integration of sustainable development in official policies have recently gained momentum. In this article, we investigate the extent to which WNH sites trigger sustainability-oriented approaches in surrounding regions, and how such approaches in turn influence the WNH site and its protection. The results of the study are on the one hand based on a global survey with more than 60% of the WNH sites listed in 2011, and on the other hand on a complementary literature research. Furthermore, we analyze the policy framework necessary to support WNH sites in this endeavor. We conclude that a regional approach to WNH management is necessary to ensure that WNH sites support sustainable regional development effectively, but that the core focus of WNH status must remain environmental conservation.
17. Forest conservation in a changing world: natural or cultural? Example from the Western Carpathians forests, Romania
Directory of Open Access Journals (Sweden)
Angelica Feurdean
2010-04-01
Full Text Available In order to plan for the future management of some of the most biodiverse forests of Europe, it is essential that we understand under which condition they arose and the time and processes responsible for their variability. Here, I highlight the main findings from the palaeoecological (pollen and charcoal, archaeological and historical investigation comprising the last 6000 years, in the Apuseni Natural Park, NW Romania and discuss the effect of the past land use and forest management on these forests. I then ask what does it mean in term of conservation values if these forests are not natural but a human product and bring up the relevance of cultural landscape for conservation.
18. Citizen science can improve conservation science, natural resource management, and environmental protection
Science.gov (United States)
McKinley, Duncan C.; Miller-Rushing, Abe J.; Ballard, Heidi L.; Bonney, Rick; Brown, Hutch; Cook-Patton, Susan; Evans, Daniel M.; French, Rebecca A.; Parrish, Julia; Phillips, Tina B.; Ryan, Sean F.; Shanley, Lea A.; Shirk, Jennifer L.; Stepenuck, Kristine F.; Weltzin, Jake F.; Wiggins, Andrea; Boyle, Owen D.; Briggs, Russell D.; Chapin, Stuart F.; Hewitt, David A.; Preuss, Peter W.; Soukup, Michael A.
2017-01-01
Citizen science has advanced science for hundreds of years, contributed to many peer-reviewed articles, and informed land management decisions and policies across the United States. Over the last 10 years, citizen science has grown immensely in the United States and many other countries. Here, we show how citizen science is a powerful tool for tackling many of the challenges faced in the field of conservation biology. We describe the two interwoven paths by which citizen science can improve conservation efforts, natural resource management, and environmental protection. The first path includes building scientific knowledge, while the other path involves informing policy and encouraging public action. We explore how citizen science is currently used and describe the investments needed to create a citizen science program. We find that:Citizen science already contributes substantially to many domains of science, including conservation, natural resource, and environmental science. Citizen science informs natural resource management, environmental protection, and policymaking and fosters public input and engagement.Many types of projects can benefit from citizen science, but one must be careful to match the needs for science and public involvement with the right type of citizen science project and the right method of public participation.Citizen science is a rigorous process of scientific discovery, indistinguishable from conventional science apart from the participation of volunteers. When properly designed, carried out, and evaluated, citizen science can provide sound science, efficiently generate high-quality data, and help solve problems.
19. Proximity to forests drives bird conservation value of coffee plantations: implications for certification.
Science.gov (United States)
Anand, Mandyam Osuri; Krishnaswamy, Jagdish; Das, Arundhati
2008-10-01
Widespread loss of primary habitat in the tropics has led to increased interest in production landscapes for biodiversity conservation. In the Western Ghats biodiversity hotspot in India, shade coffee plantations are located in close proximity to sites of high conservation value: protected and unprotected forests. Coffee is grown here under a tree canopy that may be dominated by native tree species or by nonnative species, particularly silver oak (Grevillea robusta). We investigated the influence of properties at the local scale and the landscape scale in determining bird communities in coffee plantations, with particular emphasis on species of conservation priority. We used systematic point counts in 11 coffee plantation sites and analyzed data in a randomized linear modeling framework that addressed spatial autocorrelation. Greater proportion of silver oak at the local scale and distance to contiguous forests at the landscape scale were implicated as factors most strongly driving declines in bird species richness and abundance, while increased basal area of native tree species, a local-scale variable, was frequently related to increased bird species richness and abundance. The influence of local-scale variables increased at greater distances from the forest. Distance to forests emerged as the strongest predictor of declines in restricted-range species, with 92% reduction in the abundance of two commonly encountered restricted-range species (Pompadour Green Pigeon and Yellow-browed Bulbul) and a 43% reduction in richness of bird species restricted to Indian hill forests within 8 km of forests. Increase in proportion of silver oak from 33% to 55% was associated with 91% reduction in the abundance of one commonly encountered restricted-range species (Crimson-fronted Barbet). One conservation strategy is providing incentives to grow coffee in a biodiversity-friendly manner. One implication of our study is that plantations located at varying distances to the forest
20. Urban nature conservation: vegetation of natural areas in the Potchefstroom municipal area, North West Province, South Africa
Directory of Open Access Journals (Sweden)
S.S. Cilliers
1999-01-01
Full Text Available This study on the natural and degraded natural vegetation of natural areas in the Potchefstroom Municipal Area, forms part of a research programme on spontaneous vegetation in urban open spaces in the North West Province, South Africa. Using a numerical classification technique (TWINSPAN as a first approximation, the classification was refined by applying Braun-Blanquet procedures. The result is a phytosociological table from which 6 plant communities were recognised, which are subdivided in sub-communities and variants, resulting in 18 vegetation units. Some of these vegetation units are similar to communities described previously in natural areas. The presence of degraded natural communities suggests huge anthropogenic influences in certain areas. An ordination (DECORANA scatter diagram shows the distribution of the plant communities along gradients which could be related to vegetation structure, altitude, soil depth, rockiness of soil surface, wetness or dryness of the habitat and number of introduced species. This study contributes to the compilation of a guideline for a conservation orientated management plan for the area, but also created a wealth of new knowledge of the reaction of indigenous plant species under disturbed conditions.
1. Development of a natural practice to adapt conservation goals to global change.
Science.gov (United States)
Heller, Nicole E; Hobbs, Richard J
2014-06-01
Conservation goals at the start of the 21st century reflect a combination of contrasting ideas. Ideal nature is something that is historically intact but also futuristically flexible. Ideal nature is independent from humans, but also, because of the pervasiveness of human impacts, only able to reach expression through human management. These tensions emerge in current management rationales because scientists and managers are struggling to accommodate old and new scientific and cultural thinking, while also maintaining legal mandates from the past and commitments to preservation of individual species in particular places under the stresses of global change. Common management goals (such as integrity, wilderness, resilience), whether they are forward looking and focused on sustainability and change, or backward looking and focused on the persistence and restoration of historic states, tend to create essentialisms about how ecosystems should be. These essentialisms limit the options of managers to accommodate the dynamic, and often novel, response of ecosystems to global change. Essentialisms emerge because there is a tight conceptual coupling of place and historical species composition as an indicator of naturalness (e.g., normal, healthy, independent from humans). Given that change is increasingly the norm and ecosystems evolve in response, the focus on idealized ecosystem states is increasingly unwise and unattainable. To provide more open-ended goals, we propose greater attention be paid to the characteristics of management intervention. We suggest that the way we interact with other species in management and the extent to which those interactions reflect the interactions among other biotic organisms, and also reflect our conservation virtues (e.g., humility, respect), influences our ability to cultivate naturalness on the landscape. We call this goal a natural practice (NP) and propose it as a framework for prioritizing and formulating how, when, and where to
2. The Perceptions of Dayak Society of Losarang Indramayu to The Conservation of Natural Resources as Subsistence
Science.gov (United States)
Permana Putri, Dian
2017-02-01
This study aims to investigate the perception of local society, especially in the Dayak society in Losarang Indramayu to the importance of the natural resources conservation as subsistence. The research method of this study is qualitative approach to investigate the perception of Dayak society. The result of the research shows that the majority of Dayak local society in Losarang Indramayu is farming rice and vegetables through intercropping. Dayak society of Losarang Indramayu really appreciates to the preservation of natural resources. They believe that if they keep nature, then nature will also be friendly with them. One of the way to save the nature is by doing Pepe ritual, becoming vegetarian, and do not destroy animals around them. Dayak society of Losarang believes that each animal would also like to have the desire to live, taste, and imagination just like humans. Furthermore, they also build a special building that is used to respect all kinds of animal. The building uses bamboo as walls and fibers as roof. In that building, they raise many kinds of farm animal such as chickens, cows, goats, and pigs. By preserving the fauna, they believe that the crops will be abundant every year. By making the society to be aware about the importance of the natural resource and express their aspiration to the policymakers is a step to establish the sustainability of natural resources. Furthermore, in the management of natural resources by the stakeholders, the local society perception needs to be appreciated, understood, and considered.
3. A roadmap for knowledge exchange and mobilization research in conservation and natural resource management.
Science.gov (United States)
Nguyen, Vivian M; Young, Nathan; Cooke, Steven J
2017-08-01
Scholars across all disciplines have long been interested in how knowledge moves within and beyond their community of peers. Rapid environmental changes and calls for sustainable management practices mean the best knowledge possible is needed to inform decisions, policies, and practices to protect biodiversity and sustainably manage vulnerable natural resources. Although the conservation literature on knowledge exchange (KE) and knowledge mobilization (KM) has grown in recent years, much of it is based on context-specific case studies. This presents a challenge for learning cumulative lessons from KE and KM research and thus effectively using knowledge in conservation and natural resources management. Although continued research on the gap between knowledge and action is valuable, overarching conceptual frameworks are now needed to enable summaries and comparisons across diverse KE-KM research. We propose a knowledge-action framework that provides a conceptual roadmap for future research and practice in KE/KM with the aim of synthesizing lessons learned from contextual case studies and guiding the development and testing of hypotheses in this domain. Our knowledge-action framework has 3 elements that occur at multiple levels and scales: knowledge production (e.g., academia and government), knowledge mediation (e.g., knowledge networks, actors, relational dimension, and contextual dimension), and knowledge-based action (e.g., instrumental, symbolic, and conceptual). The framework integrates concepts from the sociology of science in particular, and serves as a guide to further comprehensive understanding of knowledge exchange and mobilization in conservation and sustainable natural resource management. © 2016 Society for Conservation Biology.
4. Factors influencing predation on juvenile ungulates and natural selection implications
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S. M. Barber-Meyer
2008-06-01
Full Text Available Juvenile ungulates are generally more vulnerable to predation than are adult ungulates other than senescent individuals, not only because of their relative youth, fragility, and inexperience, but also because of congenital factors. Linnell et al.’s (Wildl. Biol. 1: 209-223 extensive review of predation on juvenile ungulates concluded that research was needed to determine the predisposition of these juveniles to predation. Since then, various characteristics that potentially predispose juvenile ungulates have emerged including blood characteristics, morphometric and other condition factors, and other factors such as birth period, the mother’s experience, and spatial and habitat aspects. To the extent that any of the physical or behavioral traits possessed by juvenile ungulates have a genetic or heritable and partly independent epigenetic component that predisposes them to predation, predators may play an important role in their natural selection. We review the possible influence of these characteristics on predisposing juvenile ungulates to predation and discuss natural selection implications and potential selection mechanisms. Although juvenile ungulates as a class are likely more vulnerable to predation than all but senescent adults, our review presents studies indicating that juveniles with certain tendencies or traits are killed more often than others. This finding suggests that successful predation on juveniles is more selective than is often assumed. Because we are unable to control for (or in some cases even measure the myriad of other possible vulnerabilities such as differences in sensory abilities, intelligence, hiding abilities, tendency to travel, etc., finding selective predation based on the relatively few differences we can measure is noteworthy and points to the significant role that predation on juveniles has in the natural selection of ungulates. Future research should compare characteristics, especially those known to
5. The rise and fall of the nature conservation movement in Japan in relation to some cultural values
Science.gov (United States)
1989-01-01
The Japanese are traditionally regarded as nature-loving people, living in “harmony” with nature. However, this assumption is difficult to accept when observing the environmental problems in Japan. How can one explain the incongruities? Has the Japanese people's attitude toward nature changed as Japan has modernized? Is the concept of the nature-loving Japanese merely a myth? Is there another reason to explain this contradiction? This study shows political and economic origins of the paradox. The origin of the Japanese traditional idea of nature is fear and reverence of nature based on a primitive religion that developed in a rural subsistence living situation. Aesthetic and spiritual values of nature for cultural, educational, and intellectual entertainment were developed by the ruling class in the seventh century. Japan's first nature conservation movement, imported from the West, developed among the intellectual community and was advocated and promoted by the elite in the Meiji period (1868 1911). However, because deep commitment was lacking, the movement was abused by the military government before World War II. In the early 1970s the nature conservation movement seemed to be on the ascendancy, mainly because it was combined with the antipollution movement claiming the basic rights of survival. The Japanese nature conservation movement is still in the embryonic stage; in the future, the blending of some traditional resource management with the scientific philosophy of nature conservation may help promote the new wave of nature conservation in Japan.
6. Addressing potential local adaptation in species distribution models: implications for conservation under climate change
Science.gov (United States)
Hällfors, Maria Helena; Liao, Jishan; Dzurisin, Jason D. K.; Grundel, Ralph; Hyvärinen, Marko; Towle, Kevin; Wu, Grace C.; Hellmann, Jessica J.
2016-01-01
Species distribution models (SDMs) have been criticized for involving assumptions that ignore or categorize many ecologically relevant factors such as dispersal ability and biotic interactions. Another potential source of model error is the assumption that species are ecologically uniform in their climatic tolerances across their range. Typically, SDMs to treat a species as a single entity, although populations of many species differ due to local adaptation or other genetic differentiation. Not taking local adaptation into account, may lead to incorrect range prediction and therefore misplaced conservation efforts. A constraint is that we often do not know the degree to which populations are locally adapted, however. Lacking experimental evidence, we still can evaluate niche differentiation within a species' range to promote better conservation decisions. We explore possible conservation implications of making type I or type II errors in this context. For each of two species, we construct three separate MaxEnt models, one considering the species as a single population and two of disjunct populations. PCA analyses and response curves indicate different climate characteristics in the current environments of the populations. Model projections into future climates indicate minimal overlap between areas predicted to be climatically suitable by the whole species versus population-based models. We present a workflow for addressing uncertainty surrounding local adaptation in SDM application and illustrate the value of conducting population-based models to compare with whole-species models. These comparisons might result in more cautious management actions when alternative range outcomes are considered.
7. Addressing potential local adaptation in species distribution models: implications for conservation under climate change.
Science.gov (United States)
Hällfors, Maria Helena; Liao, Jishan; Dzurisin, Jason; Grundel, Ralph; Hyvärinen, Marko; Towle, Kevin; Wu, Grace C; Hellmann, Jessica J
2016-06-01
Species distribution models (SDMs) have been criticized for involving assumptions that ignore or categorize many ecologically relevant factors such as dispersal ability and biotic interactions. Another potential source of model error is the assumption that species are ecologically uniform in their climatic tolerances across their range. Typically, SDMs treat a species as a single entity, although populations of many species differ due to local adaptation or other genetic differentiation. Not taking local adaptation into account may lead to incorrect range prediction and therefore misplaced conservation efforts. A constraint is that we often do not know the degree to which populations are locally adapted. Lacking experimental evidence, we still can evaluate niche differentiation within a species' range to promote better conservation decisions. We explore possible conservation implications of making type I or type II errors in this context. For each of two species, we construct three separate Max-Ent models, one considering the species as a single population and two of disjunct populations. Principal component analyses and response curves indicate different climate characteristics in the current environments of the populations. Model projections into future climates indicate minimal overlap between areas predicted to be climatically suitable by the whole species vs. population-based models. We present a workflow for addressing uncertainty surrounding local adaptation in SDM application and illustrate the value of conducting population-based models to compare with whole-species models. These comparisons might result in more cautious management actions when alternative range outcomes are considered.
8. Local understandings of conservation in southeastern Mexico and their implications for community-based conservation as an alternative paradigm.
Science.gov (United States)
Reyes-Garcia, Victoria; Ruiz-Mallen, Isabel; Porter-Bolland, Luciana; Garcia-Frapolli, Eduardo; Ellis, Edward A; Mendez, Maria-Elena; Pritchard, Diana J; Sanchez-Gonzalez, María-Consuelo
2013-08-01
Since the 1990s national and international programs have aimed to legitimize local conservation initiatives that might provide an alternative to the formal systems of state-managed or otherwise externally driven protected areas. We used discourse analysis (130 semistructured interviews with key informants) and descriptive statistics (679 surveys) to compare local perceptions of and experiences with state-driven versus community-driven conservation initiatives. We conducted our research in 6 communities in southeastern Mexico. Formalization of local conservation initiatives did not seem to be based on local knowledge and practices. Although interviewees thought community-based initiatives generated less conflict than state-managed conservation initiatives, the community-based initiatives conformed to the biodiversity conservation paradigm that emphasizes restricted use of and access to resources. This restrictive approach to community-based conservation in Mexico, promoted through state and international conservation organizations, increased the area of protected land and had local support but was not built on locally relevant and multifunctional landscapes, a model that community-based conservation is assumed to advance. © 2013 Society for Conservation Biology.
9. Implications of genetics and current protected areas for conservation of 5 endangered primates in China.
Science.gov (United States)
Liu, Zhijin; Liu, Guangjian; Roos, Christian; Wang, Ziming; Xiang, ZuoFu; Zhu, Pingfen; Wang, Boshi; Ren, Baoping; Shi, Fanglei; Pan, Huijuan; Li, Ming
2015-12-01
Most of China's 24-28 primate species are threatened with extinction. Habitat reduction and fragmentation are perhaps the greatest threats. We used published data from a conservation genetics study of 5 endangered primates in China (Rhinopithecus roxellana, R. bieti, R. brelichi, Trachypithecus francoisi, and T. leucocephalus); distribution data on these species; and the distribution, area, and location of protected areas to inform conservation strategies for these primates. All 5 species were separated into subpopulations with unique genetic components. Gene flow appeared to be strongly impeded by agricultural land, meadows used for grazing, highways, and humans dwellings. Most species declined severely or diverged concurrently as human population and crop land cover increased. Nature reserves were not evenly distributed across subpopulations with unique genetic backgrounds. Certain small subpopulations were severely fragmented and had higher extinction risk than others. Primate mobility is limited and their genetic structure is strong and susceptible to substantial loss of diversity due to local extinction. Thus, to maximize preservation of genetic diversity in all these primate species, our results suggest protection is required for all sub-populations. Key priorities for their conservation include maintaining R. roxellana in Shennongjia national reserve, subpopulations S4 and S5 of R. bieti and of R. brelichi in Fanjingshan national reserve, subpopulation CGX of T. francoisi in central Guangxi Province, and all 3 T. leucocephalus sub-populations in central Guangxi Province. © 2015 Society for Conservation Biology.
10. POTENTIAL APPLICATIONS OF LANDSCAPE ECOLOGICAL PATCHGRADIENT MAPS IN NATURE CONSERVATIONAL LANDSCAPE PLANNING
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PÉTER CSORBA
2008-12-01
Full Text Available There are rather limited opportunities for using the results of landscape ecology in practical nature conservation. The reasonS for this are – at least partly – the different scales and frames of the two fields. For more effective cooperation there is an opportunity for landscape ecology to determine patch-gradients that are helpful for nature protection in expanding the living space of endangered species via CORINE land use-pattern in mixed use agricultural areas. Such alternative migration tracks become valuable in places, where landscape ecological corridors and stepping stone places are missing. The method applies the gradient concept of landscape structure of McGarigal and Cushman (2005. Determination of patch-gradients can be a good background material for settlement- and infrastructure planning; and for the elaboration of medium- and long term nature protection concepts or for even general landscape protection strategies as well.
11. Values in nature conservation, tourism and UNESCO World Heritage Site stewardship
DEFF Research Database (Denmark)
Liburd, Janne J.; Becken, Susanne
2017-01-01
tourism operators, public sector managers and other stakeholders from the iconic World Heritage Site and tourism destination, Australia’s Great Barrier Reef (GBR) reveal how shifting ideologies and government policies increased pressures on nature, resulting in new alliances between stewards from...... the tourism sector and national and international organizations. These alliances were built on shared nature conservation values and successfully reduced increasing development pressures. Three distinct phases in this process emerged at the GBR, which were driven by personal values held by tourism industry...... representatives, and their recognition of tourism’s reliance on nature for business success. Changing mainstream ideologies and political values can erode World Heritage and Protected Areas, and recalibrate values – including the universal values on which World Heritage Sites depend – towards more anthropocentric...
12. The potential natural vegetation of eastern Africa distribution, conservation and future changes
DEFF Research Database (Denmark)
van Breugel, Paulo
Species and ecosystems are increasingly threatened by the human activities, while climate change projections show that eastern Africa may face considerable changes in temperature and rainfall regimes. These changes pose huge challenges for the prioritization and implementation of conservation...... and sustainable management of the natural environment. There is therefore an urgent need for information that allow us to assess the current status of the region’s natural environment and to predict how this may change under future climates. This thesis aims to improve our knowledge on natural vegetation...... to the regions different vegetation types. Chapter 5 present a new approach to quickly map the distribution of species by combining species distributions from the PNV maps with that of habitat distribution models, and use this to project to what extent and where projected climate changes are likely to affect...
13. Positives and pathologies of natural resource management on private land-conservation areas.
Science.gov (United States)
Clements, Hayley S; Cumming, Graeme S
2017-06-01
In managed natural resource systems, such as fisheries and rangelands, there is a recognized trade-off between managing for short-term benefits and managing for longer term resilience. Management actions that stabilize ecological attributes or processes can improve productivity in the supply of ecosystem goods and services in the short term but erode system resilience at longer time scales. For example, fire suppression in rangelands can increase grass biomass initially but ultimately result in an undesirable, shrub-dominated system. Analyses of this phenomenon have focused largely on how management actions influence slow-changing biophysical system attributes (such as vegetation composition). Data on the frequency of management actions that reduce natural ecological variation on 66 private land-conservation areas (PLCAs) in South Africa were used to investigate how management actions are influenced by manager decision-making approaches, a largely ignored part of the problem. The pathology of natural resource management was evident on some PLCAs: increased focus on revenue-generation in decision making resulted in an increased frequency of actions to stabilize short-term variation in large mammal populations, which led to increased revenues from ecotourism or hunting. On many PLCAs, these management actions corresponded with a reduced focus on ecological monitoring and an increase in overstocking of game (i.e., ungulate species) and stocking of extralimitals (i.e., game species outside their historical range). Positives in natural resource management also existed. Some managers monitored slower changing ecological attributes, which resulted in less-intensive management, fewer extralimital species, and lower stocking rates. Our unique, empirical investigation of monitoring-management relationships illustrates that management decisions informed by revenue monitoring versus ecological monitoring can have opposing consequences for natural resource productivity and
14. Coral assemblages in Tonga: spatial patterns, replenishment capacities, and implications for conservation strategies.
Science.gov (United States)
Adjeroud, Mehdi; Briand, Marine J; Kayal, Mohsen; Dumas, Pascal
2013-07-01
Coral reefs in Tonga have been confronted by multiple threats of various origins, including large-scale disturbances and human-induced stressors. These reef communities have been poorly studied, and efficient conservation actions are urgently needed. The aim of this study was to: (1) examine the spatial distribution of coral assemblages in the lagoon of Tongatapu; (2) determine the degree to which spatial heterogeneity of adult corals is influenced by recruitment processes; and (3) examine the implications of these results in terms of conservation actions. We recorded a total of 37 adult and 28 juvenile coral genera, a mean density of 11.6 adult and 5.5 juvenile colonies m(-2), and a dominance of Montipora, Acropora, and Porites. For seven of the 10 dominant genera, spatial patterns of adults were linked to the short-term recruitment pattern history. Despite a reduced diversity and abundance of adult corals in some areas, the lagoon of Tongatapu retains the potential for replenishment through recruitment of young corals. Consequently, we suggest that conservation actions should focus on reducing factors causing coral mortality and maintain suitable conditions for the establishment and growth of juvenile corals, thus increasing the probability that they will reach maturity and participate to the maintenance of local populations. Rather than establishing a large marine protected area, which will almost certainly suffer from a lack of control and poor enforcement, alternative conservation measures could be successfully implemented through the establishment of several small village-based marine reserves, as has been undertaken in other South Pacific islands with promising results.
15. Climate change risks and conservation implications for a threatened small-range mammal species.
Directory of Open Access Journals (Sweden)
Naia Morueta-Holme
Full Text Available BACKGROUND: Climate change is already affecting the distributions of many species and may lead to numerous extinctions over the next century. Small-range species are likely to be a special concern, but the extent to which they are sensitive to climate is currently unclear. Species distribution modeling, if carefully implemented, can be used to assess climate sensitivity and potential climate change impacts, even for rare and cryptic species. METHODOLOGY/PRINCIPAL FINDINGS: We used species distribution modeling to assess the climate sensitivity, climate change risks and conservation implications for a threatened small-range mammal species, the Iberian desman (Galemys pyrenaicus, which is a phylogenetically isolated insectivore endemic to south-western Europe. Atlas data on the distribution of G. pyrenaicus was linked to data on climate, topography and human impact using two species distribution modeling algorithms to test hypotheses on the factors that determine the range for this species. Predictive models were developed and projected onto climate scenarios for 2070-2099 to assess climate change risks and conservation possibilities. Mean summer temperature and water balance appeared to be the main factors influencing the distribution of G. pyrenaicus. Climate change was predicted to result in significant reductions of the species' range. However, the severity of these reductions was highly dependent on which predictor was the most important limiting factor. Notably, if mean summer temperature is the main range determinant, G. pyrenaicus is at risk of near total extinction in Spain under the most severe climate change scenario. The range projections for Europe indicate that assisted migration may be a possible long-term conservation strategy for G. pyrenaicus in the face of global warming. CONCLUSIONS/SIGNIFICANCE: Climate change clearly poses a severe threat to this illustrative endemic species. Our findings confirm that endemic species can be
16. Conservation of the Ethiopian church forests: Threats, opportunities and implications for their management.
Science.gov (United States)
Aerts, Raf; Van Overtveld, Koen; November, Eva; Wassie, Alemayehu; Abiyu, Abrham; Demissew, Sebsebe; Daye, Desalegn D; Giday, Kidane; Haile, Mitiku; TewoldeBerhan, Sarah; Teketay, Demel; Teklehaimanot, Zewge; Binggeli, Pierre; Deckers, Jozef; Friis, Ib; Gratzer, Georg; Hermy, Martin; Heyn, Moïra; Honnay, Olivier; Paris, Maxim; Sterck, Frank J; Muys, Bart; Bongers, Frans; Healey, John R
2016-05-01
In the central and northern highlands of Ethiopia, native forest and forest biodiversity is almost confined to sacred groves associated with churches. Local communities rely on these 'church forests' for essential ecosystem services including shade and fresh water but little is known about their region-wide distribution and conservation value. We (1) performed the first large-scale spatially-explicit assessment of church forests, combining remote-sensing and field data, to assess the number of forests, their size, shape, isolation and woody plant species composition, (2) determined their plant communities and related these to environmental variables and potential natural vegetation, (3) identified the main challenges to biodiversity conservation in view of plant population dynamics and anthropogenic disturbances, and (4) present guidelines for management and policy. The 394 forests identified in satellite images were on average ~2ha in size and generally separated by ~2km from the nearest neighboring forest. Shape complexity, not size, decreased from the northern to the central highlands. Overall, 148 indigenous tree, shrub and liana species were recorded across the 78 surveyed forests. Patch α-diversity increased with mean annual precipitation, but typically only 25 woody species occurred per patch. The combined results showed that >50% of tree species present in tropical northeast Africa were still present in the 78 studied church forests, even though individual forests were small and relatively species-poor. Tree species composition of church forests varied with elevation and precipitation, and resembled the potential natural vegetation. With a wide distribution over the landscape, these church forests have high conservation value. However, long-term conservation of biodiversity of individual patches and evolutionary potential of species may be threatened by isolation, small sizes of tree species populations and disturbance, especially when considering climate
17. Replacement of natural stone in conservation of historic buildings, Evaluation of replacement of natural stone at the church of Our Lady in Breda
NARCIS (Netherlands)
Quist, W.J.
2009-01-01
In this paper the decision process and the choice for specific types of natural stone for conservation purposes are investigated. Two successive 20th century conservation campaigns at the church of Our Lady in Breda are analyzed. It was specifically investigated in how far the architects involved to
18. Combining machine learning and ontological data handling for multi-source classification of nature conservation areas
Science.gov (United States)
Moran, Niklas; Nieland, Simon; Tintrup gen. Suntrup, Gregor; Kleinschmit, Birgit
2017-02-01
Manual field surveys for nature conservation management are expensive and time-consuming and could be supplemented and streamlined by using Remote Sensing (RS). RS is critical to meet requirements of existing laws such as the EU Habitats Directive (HabDir) and more importantly to meet future challenges. The full potential of RS has yet to be harnessed as different nomenclatures and procedures hinder interoperability, comparison and provenance. Therefore, automated tools are needed to use RS data to produce comparable, empirical data outputs that lend themselves to data discovery and provenance. These issues are addressed by a novel, semi-automatic ontology-based classification method that uses machine learning algorithms and Web Ontology Language (OWL) ontologies that yields traceable, interoperable and observation-based classification outputs. The method was tested on European Union Nature Information System (EUNIS) grasslands in Rheinland-Palatinate, Germany. The developed methodology is a first step in developing observation-based ontologies in the field of nature conservation. The tests show promising results for the determination of the grassland indicators wetness and alkalinity with an overall accuracy of 85% for alkalinity and 76% for wetness.
19. Using a semi-natural stream to produce young sturgeons for conservation stocking: Maintaining natural selection during spawning and rearing
Science.gov (United States)
Kynard, B.; Pugh, D.; Parker, T.; Kieffer, M.
2011-01-01
Young sturgeons used for conservation stocking are presently produced using the same methods used for commercial culture. To determine if young sturgeons could be produced without relaxing natural selection factors, we developed a semi-natural stream where we annually studied mating of wild shortnose sturgeon (Acipenser brevirostrum) observed movement of gametes released freely during spawning, and estimated the number of larvae produced by various densities of spawned eggs. The stream had a bottom area of 18.8m2, a rubble-gravel bottom, and a mean bottom current at 0.6 depth during spawning of 48cms-1 (range, 17-126cms-1). Wild adults successfully spawned in the stream each year for 7years (2002-2008). Some females and males were more successful during spawning than others, suggesting an unequal fitness during spawning among wild individuals, which is different than the controlled spawning fitness of individuals in hatcheries. Male and female gametes spawned naturally must connect quickly in the fast current or fail, a selection factor absent in hatcheries. The number of larvae produced was inversely related to spawned egg densitym-2 (R2=0.65) and the maximum number of larvae produced was 8000-16000 (425-851larvaem-2 of bottom). Artificial spawning streams have the potential to contribute to sturgeon restoration. ?? 2011 Blackwell Verlag, Berlin.
20. Constraining the $SU(2)_R$ breaking scale in naturally R-parity conserving supersymmetric models
CERN Document Server
Huitu, K; Puolamäki, K
1997-01-01
We obtain an upper bound on the right-handed breaking scale in naturally R-parity conserving general left-right supersymmetric models. This translates into an upper bound on the right-handed gauge boson mass, $m_{W_R}\\lsim M_{SUSY}$, where $M_{SUSY}$ is the scale of SUSY breaking. This bound is independent of any assumptions for the couplings of the model, and follows from $SU(3)_c$ and $U(1)_{em}$ gauge invariance of the ground state of the theory.
1. Marine debris: Implications for conservation of rocky reefs in Manabi, Ecuador (Se Pacific Coast).
Science.gov (United States)
Figueroa-Pico, Juan; Valle, David Mero-Del; Castillo-Ruperti, Ricardo; Macías-Mayorga, Dayanara
2016-08-15
Marine debris (MD) pollution is a problem of global concern because of its impact on marine ecosystems. The current extent of this problem and its implications concerning reef conservation are unknown in Ecuador. The composition and distribution of submerged MD was assessed on two reefs using underwater surveys of geomorphological areas: crest, slope and bottom. MD items were classified according to source and use. Plastic-derived debris represents >90% of total MD found on the reefs, principally composed by plastic containers and nets. 63% of the MD was associated to fishing activities. The composition showed differences between sites and geomorphological areas, monofilament nets were found on the crests, multifilament lines on the slopes and plastic containers on the bottom. MD disposal might be a result of the influx of visitors and fishing activities. Distribution is related to bottom type, level of boating/fishing activity and benthic features.
2. Oviposition Site Selection in the Malayan Giant Frog (Limnonectes blythii) in Singapore:Conservation Implications
Institute of Scientific and Technical Information of China (English)
Vishnu Vardhan SRIDHAR; David BICKFORD
2015-01-01
Amphibians require speciifc habitats for breeding and loss or degradation of such habitats can negatively affect reproductive success. Oviposition site selection within a habitat is also important as site quality is linked to larval survivorship and metamorphic success. We investigated oviposition site preferences of the stream-breeding frog Limnonectes blythii in Singapore through surveys and habitat measurements of breeding and non-breeding sites (N =30 and 32, respectively). The study species L. blythii is classiifed as Near Threatened (NT) in the IUCN red list and is associated with medium sized forest streams. L. blythii appeared to prefer streams with higher water pH and shallower water depths for oviposition. Our ifndings have implications in conservation management as it provides the baseline for habitat restoration for creation of new and for preserving existing breeding habitat of L. blythii.
3. Whose forests, whose voices? Mining and community-based nature conservation in southeastern Madagascar
Directory of Open Access Journals (Sweden)
Antonie Kraemer
2012-11-01
Full Text Available This paper explores local experiences of private-sector led community-based nature conservation near Fort Dauphin, southeastern Madagascar through the analysis of a conservation zone managed in partnership between the Rio Tinto mining corporation, local government and local communities. The article assesses how new forms of social inclusion and exclusion are generated through changes in land and resource access. The main findings are as follows: the community-based conservation programs near the Fort Dauphin mine were effective at mobilising local people but inadvertently favored certain members of society over others, as they involved a legitimization of resource access by established landowners. This granting of resource rights to some local users entailed the exclusion of already marginalised groups of landless migrants. Without land to cultivate, these migrants were more directly dependent on forest resources for their survival. Their livelihoods were based on selling forest products such as timber and handicrafts, in addition to working the land of others. This rendered their social status and ability to participate in development programs limited. Non-resident or recently settled resource users’ voices had thereby not been adequately included in the conservation plans from the outset. Consequently, local landless migrants continued to break conservation rules, as they had no influence over the resource management process or realistic livelihoods alternatives. These circumstances reduced both the livelihood options of the poorest people near the mining site and the prospect of achieving equitable and sustainable natural resource management. RésuméNous proposons ici d’analyser des expériences locales intervenant lors du changement d’accès aux ressources naturelles dans le cadre d’un projet d’extraction minière et de conservation de la nature mené en partenariat entre une compagnie minière, le gouvernement local et les
4. Bigger is better: Improved nature conservation and economic returns from landscape-level mitigation
Science.gov (United States)
Kennedy, Christina M.; Miteva, Daniela A.; Baumgarten, Leandro; Hawthorne, Peter L.; Sochi, Kei; Polasky, Stephen; Oakleaf, James R.; Uhlhorn, Elizabeth M.; Kiesecker, Joseph
2016-01-01
Impact mitigation is a primary mechanism on which countries rely to reduce environmental externalities and balance development with conservation. Mitigation policies are transitioning from traditional project-by-project planning to landscape-level planning. Although this larger-scale approach is expected to provide greater conservation benefits at the lowest cost, empirical justification is still scarce. Using commercial sugarcane expansion in the Brazilian Cerrado as a case study, we apply economic and biophysical steady-state models to quantify the benefits of the Brazilian Forest Code (FC) under landscape- and property-level planning. We find that FC compliance imposes small costs to business but can generate significant long-term benefits to nature: supporting 32 (±37) additional species (largely habitat specialists), storing 593,000 to 2,280,000 additional tons of carbon worth $69 million to$265 million ($pertains to U.S. dollars), and marginally improving surface water quality. Relative to property-level compliance, we find that landscape-level compliance reduces total business costs by$19 million to 35 million per 6-year sugarcane growing cycle while often supporting more species and storing more carbon. Our results demonstrate that landscape-level mitigation provides cost-effective conservation and can be used to promote sustainable development. PMID:27419225 5. Remote sensing techniques for conservation and management of natural vegetation ecosystems Science.gov (United States) Parada, N. D. J. (Principal Investigator); Verdesio, J. J.; Dossantos, J. R. 1981-01-01 The importance of using remote sensing techniques, in the visible and near-infrared ranges, for mapping, inventory, conservation and management of natural ecosystems is discussed. Some examples realized in Brazil or other countries are given to evaluate the products from orbital platform (MSS and RBV imagery of LANDSAT) and aerial level (photography) for ecosystems study. The maximum quantitative and qualitative information which can be obtained from each sensor, at different level, are discussed. Based on the developed experiments it is concluded that the remote sensing technique is a useful tool in mapping vegetation units, estimating biomass, forecasting and evaluation of fire damage, disease detection, deforestation mapping and change detection in land-use. In addition, remote sensing techniques can be used in controling implantation and planning natural/artificial regeneration. 6. Nest-site competition between invasive and native cavity nesting birds and its implication for conservation. Science.gov (United States) Charter, Motti; Izhaki, Ido; Ben Mocha, Yitzchak; Kark, Salit 2016-10-01 Nesting cavities are often a limited resource that multiple species use. There is an ongoing discussion on whether invasive cavity nesting birds restrict the availability of this key limited resource. While the answer to this question has important conservation implications, little experimental work has been done to examine it. Here, we aimed to experimentally test whether alien cavity nesting birds affect the occupancy of cavities and the resulting breeding success of native cavity breeders in a large urban park located in Tel Aviv, Israel. Over three breeding seasons, we manipulated the entry size of nest boxes and compared the occupancy and breeding success of birds in nest boxes of two treatments. These included nest boxes with large-entrance and small-entrance holes. The large-entrance holes allowed access for both the native and invasive birds (the two main aliens in the park are the common mynas and rose-ringed parakeets). The smaller-entrance boxes, on the other hand, allowed only the smaller sized native cavity breeders (great tits and house sparrows) to enter the boxes but prevented the alien species from entering. We found that the large-entrance nest boxes were occupied by five different bird species, comprising three natives (great tit, house sparrow, Scops owl) and two invasive species (common myna, rose-ringed parakeet) while the small-entrance boxes were only occupied by the two native species. The alien common mynas and rose-ringed parakeets occupied 77.5% of the large-entrance nest boxes whereas native species, mainly great tits, occupied less than 9% of the large-entrance boxes and 36.5% of the small-entrance boxes. When examining the occupancy of those cavities that were not occupied by the aliens, natives occupied both the small and large-entrance nest boxes equally. Three quarters (78%) of the great tits breeding in the large-entrance boxes were usurped by common mynas during the breeding season and as a result breeding success was 7. Folklore and traditional ecological knowledge of geckos in Southern Portugal: implications for conservation and science Directory of Open Access Journals (Sweden) Vila-Viçosa Carlos M 2011-09-01 Full Text Available Abstract Traditional Ecological Knowledge (TEK and folklore are repositories of large amounts of information about the natural world. Ideas, perceptions and empirical data held by human communities regarding local species are important sources which enable new scientific discoveries to be made, as well as offering the potential to solve a number of conservation problems. We documented the gecko-related folklore and TEK of the people of southern Portugal, with the particular aim of understanding the main ideas relating to gecko biology and ecology. Our results suggest that local knowledge of gecko ecology and biology is both accurate and relevant. As a result of information provided by local inhabitants, knowledge of the current geographic distribution of Hemidactylus turcicus was expanded, with its presence reported in nine new locations. It was also discovered that locals still have some misconceptions of geckos as poisonous and carriers of dermatological diseases. The presence of these ideas has led the population to a fear of and aversion to geckos, resulting in direct persecution being one of the major conservation problems facing these animals. It is essential, from both a scientific and conservationist perspective, to understand the knowledge and perceptions that people have towards the animals, since, only then, may hitherto unrecognized pertinent information and conservation problems be detected and resolved. 8. Folklore and traditional ecological knowledge of geckos in Southern Portugal: implications for conservation and science. Science.gov (United States) Ceríaco, Luis M P; Marques, Mariana P; Madeira, Natália C; Vila-Viçosa, Carlos M; Mendes, Paula 2011-09-05 Traditional Ecological Knowledge (TEK) and folklore are repositories of large amounts of information about the natural world. Ideas, perceptions and empirical data held by human communities regarding local species are important sources which enable new scientific discoveries to be made, as well as offering the potential to solve a number of conservation problems. We documented the gecko-related folklore and TEK of the people of southern Portugal, with the particular aim of understanding the main ideas relating to gecko biology and ecology. Our results suggest that local knowledge of gecko ecology and biology is both accurate and relevant. As a result of information provided by local inhabitants, knowledge of the current geographic distribution of Hemidactylus turcicus was expanded, with its presence reported in nine new locations. It was also discovered that locals still have some misconceptions of geckos as poisonous and carriers of dermatological diseases. The presence of these ideas has led the population to a fear of and aversion to geckos, resulting in direct persecution being one of the major conservation problems facing these animals. It is essential, from both a scientific and conservationist perspective, to understand the knowledge and perceptions that people have towards the animals, since, only then, may hitherto unrecognized pertinent information and conservation problems be detected and resolved. 9. Perception and understanding of invasive alien species issues by nature conservation and horticulture professionals in Belgium. Science.gov (United States) Vanderhoeven, Sonia; Piqueray, Julien; Halford, Mathieu; Nulens, Greet; Vincke, Jan; Mahy, Grégory 2011-03-01 We conducted a survey to determine how two professional sectors in Belgium, horticulture professionals and nature reserve managers (those directly involved in conservation), view the issues associated with invasive plant species. We developed and utilized a questionnaire that addressed the themes of awareness, concept and use of language, availability of information, impacts and, finally, control and available solutions. Using co-inertia analyses, we tested to what extent the perception of invasive alien species (IAS) was dependent upon the perception of Nature in general. Only forty-two percent of respondent horticulture professionals and eighty-two percent of nature reserve managers had a general knowledge of IAS. Many individuals in both target groups nonetheless had an accurate understanding of the scientific issues. Our results therefore suggest that the manner in which individuals within the two groups view, or perceive, the IAS issue was more the result of lack of information than simply biased perceptions of target groups. Though IAS perceptions by the two groups diverged, they were on par with how they viewed Nature in general. The descriptions of IAS by participants converged with the ideas and concepts frequently found in the scientific literature. Both managers and horticulture professionals expressed a strong willingness to participate in programs designed to prevent the spread of, and damage caused by, IAS. Despite this, the continued commercial availability of many invasive species highlighted the necessity to use both mandatory and voluntary approaches to reduce their re-introduction and spread. The results of this study provide stakeholders and conservation managers with practical information on which communication and management strategies can be based. 10. Perception and Understanding of Invasive Alien Species Issues by Nature Conservation and Horticulture Professionals in Belgium Science.gov (United States) Vanderhoeven, Sonia; Piqueray, Julien; Halford, Mathieu; Nulens, Greet; Vincke, Jan; Mahy, Grégory 2011-03-01 We conducted a survey to determine how two professional sectors in Belgium, horticulture professionals and nature reserve managers (those directly involved in conservation), view the issues associated with invasive plant species. We developed and utilized a questionnaire that addressed the themes of awareness, concept and use of language, availability of information, impacts and, finally, control and available solutions. Using co-inertia analyses, we tested to what extent the perception of invasive alien species (IAS) was dependent upon the perception of Nature in general. Only forty-two percent of respondent horticulture professionals and eighty-two percent of nature reserve managers had a general knowledge of IAS. Many individuals in both target groups nonetheless had an accurate understanding of the scientific issues. Our results therefore suggest that the manner in which individuals within the two groups view, or perceive, the IAS issue was more the result of lack of information than simply biased perceptions of target groups. Though IAS perceptions by the two groups diverged, they were on par with how they viewed Nature in general. The descriptions of IAS by participants converged with the ideas and concepts frequently found in the scientific literature. Both managers and horticulture professionals expressed a strong willingness to participate in programs designed to prevent the spread of, and damage caused by, IAS. Despite this, the continued commercial availability of many invasive species highlighted the necessity to use both mandatory and voluntary approaches to reduce their re-introduction and spread. The results of this study provide stakeholders and conservation managers with practical information on which communication and management strategies can be based. 11. The Implication and Significance of Beta 2 Microglobulin: A Conservative Multifunctional Regulator Institute of Scientific and Technical Information of China (English) Ling Li; Mei Dong; Xiao-Guang Wang 2016-01-01 Objective: This review focuses on the current knowledge on the implication and significance of beta 2 microglobulin (β2M), a conservative immune molecule in vertebrate.Data Sources: The data used in this review were obtained from PubMed up to October 2015.Terms of β2M, immune response, and infection were used in the search.Study Selections: Articles related to β2M were retrieved and reviewed.Articles focusing on the characteristic and function of β2M were selected.The exclusion criteria of articles were that the studies on β2M-related molecules.Results: β2M is critical for the immune surveillance and modulation in vertebrate animals.The dysregulation of β2M is associated with multiple diseases, including endogenous and infectious diseases.β2M could directly participate in the development of cancer cells, and the level of β2M is deemed as a prognostic marker for several malignancies.It also involves in forming major histocompatibility complex (MHC class Ⅰ or MHC Ⅰ) or like heterodimers, covering from antigen presentation to immune homeostasis.Conclusions: Based on the characteristic of β2M, it or its signaling pathway has been targeted as biomedical or therapeutic tools.Moreover, β2M is highly conserved among different species, and overall structures are virtually identical, implying the versatility of β2M on applications. 12. Understanding Urban Demand for Wild Meat in Vietnam: Implications for Conservation Actions. Directory of Open Access Journals (Sweden) Rachel Shairp Full Text Available Vietnam is a significant consumer of wildlife, particularly wild meat, in urban restaurant settings. To meet this demand, poaching of wildlife is widespread, threatening regional and international biodiversity. Previous interventions to tackle illegal and potentially unsustainable consumption of wild meat in Vietnam have generally focused on limiting supply. While critical, they have been impeded by a lack of resources, the presence of increasingly organised criminal networks and corruption. Attention is, therefore, turning to the consumer, but a paucity of research investigating consumer demand for wild meat will impede the creation of effective consumer-centred interventions. Here we used a mixed-methods research approach comprising a hypothetical choice modelling survey and qualitative interviews to explore the drivers of wild meat consumption and consumer preferences among residents of Ho Chi Minh City, Vietnam. Our findings indicate that demand for wild meat is heterogeneous and highly context specific. Wild-sourced, rare, and expensive wild meat-types are eaten by those situated towards the top of the societal hierarchy to convey wealth and status and are commonly consumed in lucrative business contexts. Cheaper, legal and farmed substitutes for wild-sourced meats are also consumed, but typically in more casual consumption or social drinking settings. We explore the implications of our results for current conservation interventions in Vietnam that attempt to tackle illegal and potentially unsustainable trade in and consumption of wild meat and detail how our research informs future consumer-centric conservation actions. 13. Understanding Urban Demand for Wild Meat in Vietnam: Implications for Conservation Actions. Science.gov (United States) Shairp, Rachel; Veríssimo, Diogo; Fraser, Iain; Challender, Daniel; MacMillan, Douglas 2016-01-01 Vietnam is a significant consumer of wildlife, particularly wild meat, in urban restaurant settings. To meet this demand, poaching of wildlife is widespread, threatening regional and international biodiversity. Previous interventions to tackle illegal and potentially unsustainable consumption of wild meat in Vietnam have generally focused on limiting supply. While critical, they have been impeded by a lack of resources, the presence of increasingly organised criminal networks and corruption. Attention is, therefore, turning to the consumer, but a paucity of research investigating consumer demand for wild meat will impede the creation of effective consumer-centred interventions. Here we used a mixed-methods research approach comprising a hypothetical choice modelling survey and qualitative interviews to explore the drivers of wild meat consumption and consumer preferences among residents of Ho Chi Minh City, Vietnam. Our findings indicate that demand for wild meat is heterogeneous and highly context specific. Wild-sourced, rare, and expensive wild meat-types are eaten by those situated towards the top of the societal hierarchy to convey wealth and status and are commonly consumed in lucrative business contexts. Cheaper, legal and farmed substitutes for wild-sourced meats are also consumed, but typically in more casual consumption or social drinking settings. We explore the implications of our results for current conservation interventions in Vietnam that attempt to tackle illegal and potentially unsustainable trade in and consumption of wild meat and detail how our research informs future consumer-centric conservation actions. 14. Density-dependent productivity depression in Pyrenean Bearded Vultures: implications for conservation. Science.gov (United States) Carrete, Martina; Donázar, José A; Margalida, Antoni 2006-10-01 The main objective of many conservation programs is to increase population size by improving a species' survival and reproduction. However, density dependence of demographic parameters may confound this approach. In this study we used a 25-year data set on Bearded Vultures (Gypaetus barbatus) in Spain to evaluate the consequences of population growth on reproductive performance. Unlike its coefficient of variation (cv), mean annual productivity decreased with increasing population size. After controlling for territorial heterogeneity, productivity also was negatively related to the distance to the nearest conspecific breeding pair and to supplementary feeding points where floaters congregate. These results suggest that vulture populations are regulated as posited by the site-dependency hypothesis: as the population increases, average productivity decreases because progressively poorer territories are used. The combined effects of the shrinkage of territories and the presence of floaters around supplementary feeding points seem to be the main causes of productivity decline and are therefore the main determinants of territory quality. This has conservation implications, especially concerning the role of supplementary feeding points. Supplementary feeding should be reviewed given that its usefulness in reducing preadult mortality has not yet been proved and its effect on productivity, as our results suggest, is negative. 15. Species Richness and Community Structure on a High Latitude Reef: Implications for Conservation and Management Directory of Open Access Journals (Sweden) Wayne Houston 2011-07-01 Full Text Available In spite of the wealth of research on the Great Barrier Reef, few detailed biodiversity assessments of its inshore coral communities have been conducted. Effective conservation and management of marine ecosystems begins with fine-scale biophysical assessments focused on diversity and the architectural species that build the structural framework of the reef. In this study, we investigate key coral diversity and environmental attributes of an inshore reef system surrounding the Keppel Bay Islands near Rockhampton in Central Queensland, Australia, and assess their implications for conservation and management. The Keppels has much higher coral diversity than previously found. The average species richness for the 19 study sites was ~40 with representatives from 68% of the ~244 species previously described for the southern Great Barrier Reef. Using scleractinian coral species richness, taxonomic distinctiveness and coral cover as the main criteria, we found that five out of 19 sites had particularly high conservation value. A further site was also considered to be of relatively high value. Corals at this site were taxonomically distinct from the others (representatives of two families were found here but not at other sites and a wide range of functionally diverse taxa were present. This site was associated with more stressful conditions such as high temperatures and turbidity. Highly diverse coral communities or biodiversity ‘hotspots’ and taxonomically distinct reefs may act as insurance policies for climatic disturbance, much like Noah’s Arks for reefs. While improving water quality and limiting anthropogenic impacts are clearly important management initiatives to improve the long-term outlook for inshore reefs, identifying, mapping and protecting these coastal ‘refugia’ may be the key for ensuring their regeneration against catastrophic climatic disturbance in the meantime. 16. Congruencies between photoautotrophic groups in springs of the Italian Alps: implications for conservation strategies Directory of Open Access Journals (Sweden) Marco CANTONATI 2011-09-01 Full Text Available Even though a number of studies have demonstrated the importance of photoautotrophic organisms in spring habitats, investigations that consider several photoautotrophic taxonomic groups are lacking. Within the framework of a multidisciplinary project on springs of the south-eastern Alps, we studied algae, diatoms, lichens, and bryophytes and (1 compared the alpha, beta and gamma diversity, and the composition of the studied groups between carbonate and siliceous springs, (2 estimated the nonrandomness of species combinations within organismal groups, and (3 examined the congruence in species assemblage patterns across taxonomic groups. In 40 springs, 69 species of algae, 110 species of diatoms, 29 species of lichens, and 62 species of bryophytes were found. Diatoms, lichens and bryophytes had higher species-richness in siliceous springs, while other algae had higher richness in carbonate springs. For all taxonomic groups, carbonate and siliceous springs host different assemblages, indicating that both types of substrata contribute to the overall regional diversity of spring photoautotrophs. In individual springs, the photoautotroph groups are characterised by a similar proportion of species of their regional pool, and form relatively speciespoor communities with a high turnover of species among springs. This pattern has important implications for conservation, suggesting that the protection of single sites might not be effective, and that a biodiversity conservation plan for spring habitats should be developed at the regional level, and include a network of sites. Interestingly, the co-occurrence indices suggested that, in individual springs, stochastic processes might the most important mechanisms in the establishment of local assemblages. A weak cross-taxon congruency was found, suggesting that a single taxon surrogate will not adequately represent other photoautotrophic groups. Therefore, spring conservation plans for photoautotrophs should 17. Traditional use and management of NTFPs in Kangchenjunga Landscape: implications for conservation and livelihoods. Science.gov (United States) Uprety, Yadav; Poudel, Ram C; Gurung, Janita; Chettri, Nakul; Chaudhary, Ram P 2016-05-03 Non-timber Forest Products (NTFPs), an important provisioning ecosystem services, are recognized for their contribution in rural livelihoods and forest conservation. Effective management through sustainable harvesting and market driven commercialization are two contrasting aspects that are bringing challenges in development of NTFPs sector. Identifying potential species having market value, conducting value chain analyses, and sustainable management of NTFPs need analysis of their use patterns by communities and trends at a regional scale. We analyzed use patterns, trends, and challenges in traditional use and management of NTFPs in the southern slope of Kangchenjunga Landscape, Eastern Himalaya and discussed potential implications for conservation and livelihoods. A total of 739 species of NTFPs used by the local people of Kangchenjunga Landscape were reported in the reviewed literature. Of these, the highest number of NTFPs was documented from India (377 species), followed by Nepal (363) and Bhutan (245). Though the reported species were used for 24 different purposes, medicinal and edible plants were the most frequently used NTFP categories in the landscape. Medicinal plants were used in 27 major ailment categories, with the highest number of species being used for gastro-intestinal disorders. Though the Kangchenjunga Landscape harbors many potential NTFPs, trade of NTFPs was found to be nominal indicating lack of commercialization due to limited market information. We found that the unsustainable harvesting and lack of marketing were the major constraints for sustainable management of NTFPs sector in the landscape despite of promising policy provisions. We suggest sustainable harvesting practices, value addition at local level, and marketing for promotion of NTFPs in the Kangchenjunga Landscape for income generation and livelihood improvement that subsequently contributes to conservation. 18. Public perceptions of snakes and snakebite management: implications for conservation and human health in southern Nepal. Science.gov (United States) Pandey, Deb Prasad; Subedi Pandey, Gita; Devkota, Kamal; Goode, Matt 2016-06-02 Venomous snakebite and its effects are a source of fear for people living in southern Nepal. As a result, people have developed a negative attitude towards snakes, which can lead to human-snake conflicts that result in killing of snakes. Attempting to kill snakes increases the risk of snakebite, and actual killing of snakes contributes to loss of biodiversity. Currently, snake populations in southern Nepal are thought to be declining, but more research is needed to evaluate the conservation status of snakes. Therefore, we assessed attitudes, knowledge, and awareness of snakes and snakebite by Chitwan National Park's (CNP) buffer zone (BZ) inhabitants in an effort to better understand challenges to snake conservation and snakebite management. The results of this study have the potential to promote biodiversity conservation and increase human health in southern Nepal and beyond. We carried out face-to-face interviews of 150 randomly selected CNP BZ inhabitants, adopting a cross-sectional mixed research design and structured and semi-structured questionnaires from January-February 2013. Results indicated that 43 % of respondents disliked snakes, 49 % would exterminate all venomous snakes, and 86 % feared snakes. Farmers were the most negative and teachers were the most ambivalent towards snakes. Respondents were generally unable to identify different snake species, and were almost completely unaware of the need of conserve snakes and how to prevent snakebites. Belief in a snake god, and the ability of snakes to absorb poisonous gases from the atmosphere were among many superstitions that appeared to predispose negativity towards snakes of BZ residents. People with predisposed negativity towards snakes were not proponents of snake conservation. Fear, negativity, ambivalence towards, and ignorance about, snakes and the need for snake conservation were strong indicators of the propensity to harm or kill snakes. It seems that if wanton killing of snakes continues 19. Allozyme Genetic Diversity and Conservation Strategy of Ten Natural Populations of Pinus bungeana Zuuc. ex Endl Institute of Scientific and Technical Information of China (English) Li Bin; Gu Wanchun; Chen Xiaoyang 2003-01-01 Pinus bungeana is a three-needle pine with typical fragmented distribution in central and northwestern China. Its natural resources are gradually decreasing and need to be conserved. For conserving genetic diversity of P. bungeana, the authors sampled 10 natural populations in its distribution areas and conducted the analysis of isozymes. Thirty one loci with 53 alleles on the basis of 16 enzyme systems were assayed. The parameters of genetic diversity at species and population level are respectively as follows: As= 1.742, Ae[s] = 1.49, Ps= 54.8%, He[s] = 0.162, Ap= 1.39, Ae[p]= 1.30, Pp= 34.85, He[p] = 0.0986. In comparison with other pines, P. bungeana possesses a slightly low amount of genetic variation especially at the population level. By contrast, the level of population genetic differentiation (GST = 0.135) is higher compared to other pines. All ten populations are divided into three groups according to Nei's genetic identity (I). There is a slight relation (r = 0.31) between genetic distance and geographical distance.Some populations are obviously deviate from Hardy-Weinberg equilibrium but the total population is basically accordant with Hardy-Weinberg equilibrium. The correlation analysis between allele frequencies and ecological factors showed that the alleles at loci of Idh and Pgi-2 had gradient variation trends of their frequencies. The sample capturing curves' analysis indicated that the captured alleles increased when the number of sampled populations increased and 99% out of whole allele pool of ten populations would be captured when five populations were randomly selected. At last,. the population genetic structure of P. bungeana and its conservation strategy were discussed. 20. Residential energy use and conservation in Venezuela: Results and implications of a household survey in Caracas Energy Technology Data Exchange (ETDEWEB) Figueroa, M.J.; Ketoff, A.; Masera, O. 1992-10-01 This document presents the final report of a study of residential energy use in Caracas, the capital of Venezuela. It contains the findings of a household energy-use survey held in Caracas in 1988 and examines options for introducing energy conservation measures in the Venezuelan residential sector. Oil exports form the backbone of the Venezuelan economy. Improving energy efficiency in Venezuela will help free domestic oil resources that can be sold to the rest of the world. Energy conservation will also contribute to a faster recovery of the economy by reducing the need for major investments in new energy facilities, allowing the Venezuelan government to direct its financial investments towards other areas of development. Local environmental benefits will constitute an important additional by-product of implementing energy-efficiency policies in Venezuela. Caracass residential sector shows great potential for energy conservation. The sector is characterized by high saturation levels of major appliances, inefficiency of appliances available in the market, and by careless patterns of energy use. Household energy use per capita average 6.5 GJ/per year which is higher than most cities in developing countries; most of this energy is used for cooking. Electricity accounts for 41% of all energy use, while LPG and natural gas constitute the remainder. Specific options for inducing energy conservation and energy efficiency in Caracass residential sector include energy-pricing policies, fuel switching, particularly from electricity to gas, improving the energy performance of new appliances and customer information. To ensure the accomplishment of an energy-efficiency strategy, a concerted effort by energy users, manufacturers, utility companies, government agencies, and research institutions will be needed. 1. Patterns of morphological variation of extant sloth skulls and their implication for future conservation efforts. Science.gov (United States) Hautier, Lionel; Billet, Guillaume; Eastwood, Bethany; Lane, Jemima 2014-06-01 Several studies have shown an increased morphological variability of sloths from mammalian norms, affecting varied phenotypic traits from skeletal parts to soft tissues. We present here the first descriptive comparison of the whole skull morphology within the two extant sloth genera, combining geometric morphometric approaches with comparative anatomy. We used these methods to explore the patterns of the intra- and interspecific morphological variation of the skull with regard to several factors such as phylogeny, geography, allometry, or sexual dimorphism. Our study first revealed strong phylogenetic and geographical imprints on the cranial and mandibular morphological traits. This result demonstrates the importance of accurate knowledge of species and their geographical distributions; here we show from an example pertaining to Bradypus variegatus populations the implications this has on conservation management. Moreover, in order to control the amount of this detected variation, we tentatively compared sloths to a wide range of mammalian species. Our analysis found no significant increase in the average deviation of skull shape within each investigated sloth species compared to other mammals. This suggests that the intraspecific cranial variation in sloths does not depart significantly from the variation observed in other mammals. This result has positive implications for the demarcation of anatomical regions that maintain high levels of morphological variation in sloths. 2. Contrasting fish behavior in artificial seascapes with implications for resources conservation. Science.gov (United States) Koeck, Barbara; Alós, Josep; Caro, Anthony; Neveu, Reda; Crec'hriou, Romain; Saragoni, Gilles; Lenfant, Philippe 2013-01-01 Artificial reefs are used by many fisheries managers as a tool to mitigate the impact of fisheries on coastal fish communities by providing new habitat for many exploited fish species. However, the comparison between the behavior of wild fish inhabiting either natural or artificial habitats has received less attention. Thus the spatio-temporal patterns of fish that establish their home range in one habitat or the other and their consequences of intra-population differentiation on life-history remain largely unexplored. We hypothesize that individuals with a preferred habitat (i.e. natural vs. artificial) can behave differently in terms of habitat use, with important consequences on population dynamics (e.g. life-history, mortality, and reproductive success). Therefore, using biotelemetry, 98 white seabream (Diplodus sargus) inhabiting either artificial or natural habitats were tagged and their behavior was monitored for up to eight months. Most white seabreams were highly resident either on natural or artificial reefs, with a preference for the shallow artificial reef subsets. Connectivity between artificial and natural reefs was limited for resident individuals due to great inter-habitat distances. The temporal behavioral patterns of white seabreams differed between artificial and natural reefs. Artificial-reef resident fish had a predominantly nocturnal diel pattern, whereas natural-reef resident fish showed a diurnal diel pattern. Differences in diel behavioral patterns of white seabream inhabiting artificial and natural reefs could be the expression of realized individual specialization resulting from differences in habitat configuration and resource availability between these two habitats. Artificial reefs have the potential to modify not only seascape connectivity but also the individual behavioral patterns of fishes. Future management plans of coastal areas and fisheries resources, including artificial reef implementation, should therefore consider the 3. Contrasting fish behavior in artificial seascapes with implications for resources conservation. Directory of Open Access Journals (Sweden) Barbara Koeck Full Text Available Artificial reefs are used by many fisheries managers as a tool to mitigate the impact of fisheries on coastal fish communities by providing new habitat for many exploited fish species. However, the comparison between the behavior of wild fish inhabiting either natural or artificial habitats has received less attention. Thus the spatio-temporal patterns of fish that establish their home range in one habitat or the other and their consequences of intra-population differentiation on life-history remain largely unexplored. We hypothesize that individuals with a preferred habitat (i.e. natural vs. artificial can behave differently in terms of habitat use, with important consequences on population dynamics (e.g. life-history, mortality, and reproductive success. Therefore, using biotelemetry, 98 white seabream (Diplodus sargus inhabiting either artificial or natural habitats were tagged and their behavior was monitored for up to eight months. Most white seabreams were highly resident either on natural or artificial reefs, with a preference for the shallow artificial reef subsets. Connectivity between artificial and natural reefs was limited for resident individuals due to great inter-habitat distances. The temporal behavioral patterns of white seabreams differed between artificial and natural reefs. Artificial-reef resident fish had a predominantly nocturnal diel pattern, whereas natural-reef resident fish showed a diurnal diel pattern. Differences in diel behavioral patterns of white seabream inhabiting artificial and natural reefs could be the expression of realized individual specialization resulting from differences in habitat configuration and resource availability between these two habitats. Artificial reefs have the potential to modify not only seascape connectivity but also the individual behavioral patterns of fishes. Future management plans of coastal areas and fisheries resources, including artificial reef implementation, should therefore 4. Nonfamilial Hypertrophic Cardiomyopathy: Prevalence, Natural History, and Clinical Implications. Science.gov (United States) Ingles, Jodie; Burns, Charlotte; Bagnall, Richard D; Lam, Lien; Yeates, Laura; Sarina, Tanya; Puranik, Rajesh; Briffa, Tom; Atherton, John J; Driscoll, Tim; Semsarian, Christopher 2017-04-01 Yield of causative variants in hypertrophic cardiomyopathy (HCM) is increased in some probands, suggesting different clinical subgroups of disease occur. We hypothesized that a negative family history and no sarcomere mutations represent a nonfamilial subgroup of HCM. We sought to determine the prevalence, natural history, and potential clinical implications of this nonfamilial subgroup of HCM. Four hundred and thirteen unrelated probands with HCM seen in a specialized HCM center between 2002 and 2015 and genetic testing performed were included in this retrospective cohort study. There were 251 (61%) probands with no reported family history of HCM, including 166 (40% of total) probands with no sarcomere mutation, that is, nonfamilial HCM. Quantified family pedigree data revealed no difference in mean number of first-degree relatives screened between nonfamilial and sarcomere-positive groups. Adjusted predictors of nonfamilial status were older age (odds ratio, 1.04; 95% confidence interval, 1.02-1.06; P=0.0001), male sex (odds ratio, 1.96; 95% confidence interval, 1.11-3.45; P=0.02), hypertension (odds ratio, 2.80; 95% confidence interval, 1.57-5.00; P=0.0005), and nonasymmetric septal morphology (odds ratio, 3.41; 95% confidence interval, 1.64-7.08; P=0.001). They had a less severe clinical course with greater event-free survival from major cardiac events (P=0.04) compared with sarcomere-positive HCM probands. Genotype prediction scores showed good performance in identifying genotype-positive patients (area under the curve, 0.71-0.75) and, in combination with pedigree characteristics, were further improved. Approximately 40% of HCM probands have a nonfamilial subtype, with later onset and less severe clinical course. We propose a revised clinical pathway for management, highlighting the role of genetic testing, a detailed pedigree, and refined clinical surveillance recommendations for family members. © 2017 American Heart Association, Inc. 5. Effects of a coordinated farmland bird conservation project on farmers' intentions to implement nature conservation practices - Evidence from the Swedish Volunteer & Farmer Alliance. Science.gov (United States) Josefsson, Jonas; Lokhorst, Anne Marike; Pärt, Tomas; Berg, Åke; Eggers, Sönke 2017-02-01 To increase the efficacy of agri-environmental schemes (AES), as well as farmers' environmental engagement, practitioners are increasingly turning to collective forms of agri-environmental management. As yet, empirical evidence from such approaches is relatively scarce. Here, we examined a farmland bird conservation project coordinated by BirdLife Sweden, the Swedish Volunteer & Farmer Alliance (SVFA). The key features of the SVFA were farmland bird inventories from volunteering birdwatchers and on-farm visits to individual farmers from conservation advisors for guidance on AES as well as unsubsidised practices. Using an ex-post application of the theory of planned behaviour across project participants and a randomly sampled control group of farmers we assessed how SVFA affected behavioural intentions relating to AES and unsubsidised conservation, and how the behaviour was affected by attitudes, perceived social norms and perceived behavioural control. We also included a measure of self-identity as a conservationist to assess its importance for behavioural intentions, and if SVFA stimulated this self-identity. SVFA farmers reported greater commitment to implementing AES and unsubsidised conservation, as compared to the control group. However, greater commitment was associated with more positive attitudes for unsubsidised conservation only and not for AES, underlining the inability of existing AES to prompt intrinsic motivation. There were also differences between farmers within SVFA, where farmers applying to the project were motivated by social influences, while farmers recruited by project managers were motivated by their personal beliefs regarding nature conservation. Finally, farmers' self-perceived ability to perform practices (i.e. perceived behavioural control) was important for their commitment to implementing AES as well as unsubsidised practices. Therefore, increasing farmers' awareness regarding the availability and, not least, practicability of 6. The integration of the protection of nature conservation areas in Dutch spatial planning law and environmental management law NARCIS (Netherlands) Blomberg, A.B.; De Gier, A.A.J.; Robbe, J. 2009-01-01 An important question concerning the protection of designated areas in Dutch environmental law is the extent to which area protection plays a part in other fields of Dutch law. The question of integrating the protection of nature reserves as regulated in the Dutch Nature Conservation Act 1998, which 7. Zero-tolerance biosecurity protects high-conservation-value island nature reserve. Science.gov (United States) Scott, John K; McKirdy, Simon J; van der Merwe, Johann; Green, Roy; Burbidge, Andrew A; Pickles, Greg; Hardie, Darryl C; Morris, Keith; Kendrick, Peter G; Thomas, Melissa L; Horton, Kristin L; O'Connor, Simon M; Downs, Justin; Stoklosa, Richard; Lagdon, Russell; Marks, Barbara; Nairn, Malcolm; Mengersen, Kerrie 2017-04-10 Barrow Island, north-west coast of Australia, is one of the world's significant conservation areas, harboring marsupials that have become extinct or threatened on mainland Australia as well as a rich diversity of plants and animals, some endemic. Access to construct a Liquefied Natural Gas (LNG) plant, Australia's largest infrastructure development, on the island was conditional on no non-indigenous species (NIS) becoming established. We developed a comprehensive biosecurity system to protect the island's biodiversity. From 2009 to 2015 more than 0.5 million passengers and 12.2 million tonnes of freight were transported to the island under the biosecurity system, requiring 1.5 million hrs of inspections. No establishments of NIS were detected. We made four observations that will assist development of biosecurity systems. Firstly, the frequency of detections of organisms corresponded best to a mixture log-normal distribution including the high number of zero inspections and extreme values involving rare incursions. Secondly, comprehensive knowledge of the island's biota allowed estimation of false positive detections (62% native species). Thirdly, detections at the border did not predict incursions on the island. Fourthly, the workforce detected more than half post-border incursions (59%). Similar approaches can and should be implemented for all areas of significant conservation value. 8. Genetic diversity of the endangered species Rosa rugosa Thunb. in China and implications for conservation strategies Institute of Scientific and Technical Information of China (English) Ji-Hong YANG; Shu-Ping ZHANG; Jian LIU; Wen ZHAI; Ren-Qing WANG 2009-01-01 Rosa rugosa Thunb. is one of the dominant and important shrub species in estuary dunes and shingle beaches of northern China. However, its area of distribution, the number of populations, and the size of each population have decreased rapidly in the past two decades because of habitat degradation and loss. Random amplified polymorphic DNA markers were used to determine the genetic diversity of four remaining large natural populations of R. rugosa and to discuss an effective conservation strategy for this endangered species in China. High genetic variations were detected in R. rugosa populations in China. The mean percentage of polymorphic loci (P%) within four local populations was 57.99%, with the P% of the total population being 75.30%. Mean Shannon's information index (H_0) was 0.2826, whereas total H_0 was 0.3513. The genetic differentiation among populations was 0.1878, which indicates that most genetic diversity occurs within populations. Population Tumenjiang (TMJ) showed the highest genetic diversity (P% = 66.27%; H_0 = 0.3117) and contained two exclusive bands. Population Changshandao (CSD) showed higher genetic diversity (P% = 59.04%; H_0 = 0.3065). Populations TMJ and CSD contained 95.33% and 99.33%, respectively, of loci with moderate to high frequency (P>0.05) of the total population. These results indicate that populations TMJ and CSD should be given priority for in situ conservation and regarded as seed or propagule sources for ex situ conservation. The results of the present study also suggest that R. rugosa in China has become endangered as a result of human actions rather than genetic depression of populations; thus, human interference should be absolutely forbidden in R. rugosa habitats. 9. Habitat association and conservation implications of endangered Francois' langur (Trachypithecus francoisi. Directory of Open Access Journals (Sweden) Yajie Zeng Full Text Available Francois' langur (Trachypithecus francoisi is an endangered primate and endemic to the limestone forests of the tropical and subtropical zone of northern Vietnam and South-west China with a population of about 2,000 individuals. Conservation efforts are hampered by limited knowledge of habitat preference in its main distribution area. We surveyed the distribution of Francois' langur and modeled the relationship between the probability of use and habitat features in Mayanghe National Nature Reserve, Guizhou, China. The main objectives of this study were to provide quantitative information on habitat preference, estimating the availability of suitable habitat, and providing management guidelines for the effective conservation of this species. By comparing 92 used locations with habitat available in the reserve, we found that Francois' langur was mainly distributed along valleys and proportionally, used bamboo forests and mixed conifer-broadleaf forests more than their availability, whereas they tended to avoid shrubby areas and coniferous forests. The langur tended to occur at sites with lower elevation, steeper slope, higher tree canopy density, and a close distance to roads and water. The habitat occupancy probability was best modeled by vegetation type, vegetation coverage, elevation, slope degree, distances to nearest water, paved road, and farmland edge. The suitable habitat in this reserve concentrated in valleys and accounted for about 25% of the total reserve area. Our results showed that Francois' langur was not only restricted at the landscapes level at the regions with karst topography, limestone cliffs, and caves, but it also showed habitat preference at the local scale. Therefore, the protection and restoration of the langur preferred habitats such as mixed conifer-broadleaf forests are important and urgent for the conservation of this declining species. 10. Genetic Diversity and Population Structure of Mesoamerican Jaguars (Panthera onca): Implications for Conservation and Management Science.gov (United States) Wultsch, Claudia; Caragiulo, Anthony; Dias-Freedman, Isabela; Quigley, Howard; Rabinowitz, Salisa; Amato, George 2016-01-01 Mesoamerican jaguars (Panthera onca) have been extirpated from over 77% of their historic range, inhabiting fragmented landscapes at potentially reduced population sizes. Maintaining and restoring genetic diversity and connectivity across human-altered landscapes has become a major conservation priority; nonetheless large-scale genetic monitoring of natural populations is rare. This is the first regional conservation genetic study of jaguars to primarily use fecal samples collected in the wild across five Mesoamerican countries: Belize, Costa Rica, Guatemala, Honduras, and Mexico. We genotyped 445 jaguar fecal samples and examined patterns of genetic diversity and connectivity among 115 individual jaguars using data from 12 microsatellite loci. Overall, moderate levels of genetic variation were detected (NA = 4.50 ± 1.05, AR = 3.43 ± 0.22, HE = 0.59 ± 0.04), with Mexico having the lowest genetic diversity, followed by Honduras, Guatemala, Belize, and Costa Rica. Population-based gene flow measures (FST = 0.09 to 0.15, Dest = 0.09 to 0.21), principal component analysis, and Bayesian clustering applied in a hierarchical framework revealed significant genetic structure in Mesoamerican jaguars, roughly grouping individuals into four genetic clusters with varying levels of admixture. Gene flow was highest among Selva Maya jaguars (northern Guatemala and central Belize), whereas genetic differentiation among all other sampling sites was moderate. Genetic subdivision was most pronounced between Selva Maya and Honduran jaguars, suggesting limited jaguar movement between these close geographic regions and ultimately refuting the hypothesis of contemporary panmixia. To maintain a critical linkage for jaguars dispersing through the Mesoamerican landscape and ensure long-term viability of this near threatened species, we recommend continued management and maintenance of jaguar corridors. The baseline genetic data provided by this study underscores the importance of 11. Post-independence fledgling ecology in a migratory songbird: Implications for breeding-grounds conservation Science.gov (United States) Streby, H.M.; Peterson, S.M.; Kramer, G.R.; Anderson, D.E. 2014-01-01 For migratory songbirds, breeding-grounds conservation and management plans are generally focused on habitat associated with locations of singing males and sometimes nesting females. However, habitat structure is often different in areas used for raising fledglings compared with areas used for song territories, and very little is known about habitat use by fledglings after independence from adult care. From 2010 to 2012, we used radiotelemetry to monitor 68 fledgling golden-winged warblers Vermivora chrysoptera after independence from adult care in mixed managed forests of Minnesota, US and Manitoba, Canada. This species is of high conservation concern in the US, is listed as threatened in Canada and is listed as near threatened on the International Union for Conservation of Nature Red List. We assessed distance and orientation of independent fledgling movements and we used compositional analysis to test for selection among cover types. Fledglings of this species, commonly described as a shrubland specialist, selected mature forest (78% of locations) over all other cover types, and foraged in forest canopy and understory in mixed-species flocks. Fledgling golden-winged warbler movements were apparently associated with habitat optimization (although prioritizing foraging over predator avoidance), and likely not with commencement of migration, or scouting future breeding territories. Ten days after independence, fledglings were an average of 1238 m north of their nest, which may be related to homing-target formation and the species' northward range expansion. We conclude that consideration for independent fledgling habitat associations is necessary for developing full-fledged forest management plans on the breeding grounds of migratory songbirds. 12. Nanostructure and irreversible colloidal behavior of Ca(OH)2: implications in cultural heritage conservation. Science.gov (United States) Rodriguez-Navarro, C; Ruiz-Agudo, E; Ortega-Huertas, M; Hansen, E 2005-11-22 Although Ca(OH)2 is one of the oldest art and building material used by mankind, little is known about its nanostructural and colloidal characteristics that play a crucial role in its ultimate performance as a binder in lime mortars and plasters. In particular, it is unknown why hydrated lime putty behaves as an irreversible colloid once dried. Such effect dramatically affects the reactivity and rheology of hydrated lime dispersions. Here we show that the irreversible colloidal behavior of Ca(OH)2 dispersions is the result of an oriented aggregation mechanism triggered by drying. Kinetic stability and particle size distribution analysis of oven-dried slaked lime or commercial dry hydrate dispersions exhibit a significant increase in settling speed and particle (cluster) size in comparison to slaked lime putty that has never been dried. Drying-related particle aggregation also leads to a significant reduction in surface area. Electron microscopy analyses show porous, randomly oriented, micron-sized clusters that are dominant in the dispersions both before and after drying. However, oriented aggregation of the primary Ca(OH)2 nanocrystals (approximately 60 nm in size) is also observed. Oriented aggregation occurs both before and during drying, and although limited before drying, it is extensive during drying. Nanocrystals self-assemble in a crystallographically oriented manner either along the 100 or equivalent 110 directions, or along the Ca(OH)2 basal planes, i.e., along [001]. While random aggregation appears to be reversible, oriented aggregation is not. The strong coherent bonding among oriented nanoparticles prevents disaggregation upon redispersion in water. The observed irreversible colloidal behavior associated with drying of Ca(OH)2 dispersions has important implications in heritage conservation, particularly considering that nowadays hydrated lime is often the preferred alternative to portland cement in architectural heritage conservation. Finally, our 13. Understanding the Groundwater Hydrology of a Geographically-Isolated Prairie Fen: Implications for Conservation. Directory of Open Access Journals (Sweden) Prasanna Venkatesh Sampath Full Text Available The sources of water and corresponding delivery mechanisms to groundwater-fed fens are not well understood due to the multi-scale geo-morphologic variability of the glacial landscape in which they occur. This lack of understanding limits the ability to effectively conserve these systems and the ecosystem services they provide, including biodiversity and water provisioning. While fens tend to occur in clusters around regional groundwater mounds, Ives Road Fen in southern Michigan is an example of a geographically-isolated fen. In this paper, we apply a multi-scale groundwater modeling approach to understand the groundwater sources for Ives Road fen. We apply Transition Probability geo-statistics on more than 3000 well logs from a state-wide water well database to characterize the complex geology using conditional simulations. We subsequently implement a 3-dimensional reverse particle tracking to delineate groundwater contribution areas to the fen. The fen receives water from multiple sources: local recharge, regional recharge from an extensive till plain, a regional groundwater mound, and a nearby pond. The regional sources deliver water through a tortuous, 3-dimensional "pipeline" consisting of a confined aquifer lying beneath an extensive clay layer. Water in this pipeline reaches the fen by upwelling through openings in the clay layer. The pipeline connects the geographically-isolated fen to the same regional mound that provides water to other fen clusters in southern Michigan. The major implication of these findings is that fen conservation efforts must be expanded from focusing on individual fens and their immediate surroundings, to studying the much larger and inter-connected hydrologic network that sustains multiple fens. 14. Understanding the Groundwater Hydrology of a Geographically-Isolated Prairie Fen: Implications for Conservation. Science.gov (United States) Sampath, Prasanna Venkatesh; Liao, Hua-Sheng; Curtis, Zachary Kristopher; Doran, Patrick J; Herbert, Matthew E; May, Christopher A; Li, Shu-Guang 2015-01-01 The sources of water and corresponding delivery mechanisms to groundwater-fed fens are not well understood due to the multi-scale geo-morphologic variability of the glacial landscape in which they occur. This lack of understanding limits the ability to effectively conserve these systems and the ecosystem services they provide, including biodiversity and water provisioning. While fens tend to occur in clusters around regional groundwater mounds, Ives Road Fen in southern Michigan is an example of a geographically-isolated fen. In this paper, we apply a multi-scale groundwater modeling approach to understand the groundwater sources for Ives Road fen. We apply Transition Probability geo-statistics on more than 3000 well logs from a state-wide water well database to characterize the complex geology using conditional simulations. We subsequently implement a 3-dimensional reverse particle tracking to delineate groundwater contribution areas to the fen. The fen receives water from multiple sources: local recharge, regional recharge from an extensive till plain, a regional groundwater mound, and a nearby pond. The regional sources deliver water through a tortuous, 3-dimensional "pipeline" consisting of a confined aquifer lying beneath an extensive clay layer. Water in this pipeline reaches the fen by upwelling through openings in the clay layer. The pipeline connects the geographically-isolated fen to the same regional mound that provides water to other fen clusters in southern Michigan. The major implication of these findings is that fen conservation efforts must be expanded from focusing on individual fens and their immediate surroundings, to studying the much larger and inter-connected hydrologic network that sustains multiple fens. 15. Understanding the Groundwater Hydrology of a Geographically-Isolated Prairie Fen: Implications for Conservation Science.gov (United States) Sampath, Prasanna Venkatesh; Liao, Hua-Sheng; Curtis, Zachary Kristopher; Doran, Patrick J.; Herbert, Matthew E.; May, Christopher A.; Li, Shu-Guang 2015-01-01 The sources of water and corresponding delivery mechanisms to groundwater-fed fens are not well understood due to the multi-scale geo-morphologic variability of the glacial landscape in which they occur. This lack of understanding limits the ability to effectively conserve these systems and the ecosystem services they provide, including biodiversity and water provisioning. While fens tend to occur in clusters around regional groundwater mounds, Ives Road Fen in southern Michigan is an example of a geographically-isolated fen. In this paper, we apply a multi-scale groundwater modeling approach to understand the groundwater sources for Ives Road fen. We apply Transition Probability geo-statistics on more than 3000 well logs from a state-wide water well database to characterize the complex geology using conditional simulations. We subsequently implement a 3-dimensional reverse particle tracking to delineate groundwater contribution areas to the fen. The fen receives water from multiple sources: local recharge, regional recharge from an extensive till plain, a regional groundwater mound, and a nearby pond. The regional sources deliver water through a tortuous, 3-dimensional “pipeline” consisting of a confined aquifer lying beneath an extensive clay layer. Water in this pipeline reaches the fen by upwelling through openings in the clay layer. The pipeline connects the geographically-isolated fen to the same regional mound that provides water to other fen clusters in southern Michigan. The major implication of these findings is that fen conservation efforts must be expanded from focusing on individual fens and their immediate surroundings, to studying the much larger and inter-connected hydrologic network that sustains multiple fens. PMID:26452279 16. Biogeography of Parasitic Nematode Communities in the Galapagos Giant Tortoise: Implications for Conservation Management. Directory of Open Access Journals (Sweden) Guillaume Fournié Full Text Available The Galápagos giant tortoise is an icon of the unique, endemic biodiversity of Galápagos, but little is known of its parasitic fauna. We assessed the diversity of parasitic nematode communities and their spatial distributions within four wild tortoise populations comprising three species across three Galápagos islands, and consider their implication for Galápagos tortoise conservation programmes. Coprological examinations revealed nematode eggs to be common, with more than 80% of tortoises infected within each wild population. Faecal samples from tortoises within captive breeding centres on Santa Cruz, Isabela and San Cristobal islands also were examined. Five different nematode egg types were identified: oxyuroid, ascarid, trichurid and two types of strongyle. Sequencing of the 18S small-subunit ribosomal RNA gene from adult nematodes passed with faeces identified novel sequences indicative of rhabditid and ascaridid species. In the wild, the composition of nematode communities varied according to tortoise species, which co-varied with island, but nematode diversity and abundance were reduced or altered in captive-reared animals. Evolutionary and ecological factors are likely responsible for the variation in nematode distributions in the wild. This possible species/island-parasite co-evolution has not been considered previously for Galápagos tortoises. We recommend that conservation efforts, such as the current Galápagos tortoise captive breeding/rearing and release programme, be managed with respect to parasite biogeography and host-parasite co-evolutionary processes in addition to the biogeography of the host. 17. Seoul, Keep Your Paddies! Implications for the Conservation of Hylid Species Directory of Open Access Journals (Sweden) Borzee, Amael 2015-07-01 Full Text Available Biodiversity is plummeting worldwide, and the major causes of such decline include habitat degradation and climate change. While cities do contribute to the negative impact to the environment, they can also serve as strategic centres for conservation programs. Sites qualifying as biogeographic islands within metropolitan Seoul were studied for the occurrence of two hylid species: the endangered Hyla suweonensis and the abundant H. japonica. This study demonstrates that neither habitat diversity nor surface area, but solely the occurrence of aggregated rice paddies is a requisite for H. suweonensis, hypothetically due to its strict breeding requirements. On the contrary, H. japonica occurrence was not affected by any of these factors, and all types of habitats studied were adequate for this species. The presence of an endangered species within the boundaries of one of the most populated metropolises suggests a strong natural resilience, which should be enhanced with appropriate actions. We emphasize that the management plans therein can, and should, be used as the first step in the conservation of H. suweonensis in metropolitan Seoul. 18. Population and habitat status of two endemic sand gobies in lagoon marshes - Implications for conservation Science.gov (United States) Franco, A.; Franzoi, P.; Malavasi, S.; Zucchetta, M.; Torricelli, P. 2012-12-01 Ensuring biodiversity, through the conservation of natural habitats, such as wetlands, and of their wild flora and fauna, is the main objective of the Habitat and Species Directive 92/43/EC. Within this framework, two species of Community interest, Pomatoschistus canestrinii and Knipowitschia panizzae (Gobiidae, Osteichthyes), endemisms of the Northern Adriatic lagoons, were considered. The population structure, reproductive effort, somatic growth and production of such species were investigated in marsh habitats of the Venice lagoon, as indicators of the status of the populations and their habitats. The lagoon marsh habitats hosted abundant and well structured populations, functioning also as breeding areas for these species. A certain spatial variability was also observed, possibly related to the shelter conditions of different marsh sub-habitats (e.g. marsh creeks vs. adjacent mudflats). These results were discussed in the light of the available ecological knowledge on the two species, with a particular attention to the conservation priority focused on the protection of biodiversity and of key habitats. 19. Fine-scale genetic structure of Eremosparton songoricum and implication for conservation Institute of Scientific and Technical Information of China (English) 2010-01-01 Eremosparton songoricum (Litv.) Vass. is a clonal shrub that reproduces both asexually by under-ground rhizomes and sexually by seeds. It is now a rare species with a narrow distribution in fragmented habitat patches in the Gurbantunggut Desert of Xinjiang, China. The objective of this study was to determine the spatial pattern or structure of genetic variation within population. The within-populations genetic structure of E. songoricum in a plot (10 m×10 m) was analyzed using inter simple sequence repeats (ISSR) markers. Correlograms of Moran’s I showed significant positive value was about 7 m, but changed into a negative correlation with the increase of distance, indicating strong genetic structure. The natural character of clonal reproduction, restricted seed and pollen dispersal were the main factors of influencing the spatial pattern. The knowledge of clonal structures within populations was crucial for understanding evolutionary processes and ecological adaptation. This study provided basic data for the conservation and management of E. songoricum, especially for sampling strategies for ex situ conservation. 20. Habitat fragmentation is associated to gut microbiota diversity of an endangered primate: implications for conservation. Science.gov (United States) Barelli, Claudia; Albanese, Davide; Donati, Claudio; Pindo, Massimo; Dallago, Chiara; Rovero, Francesco; Cavalieri, Duccio; Tuohy, Kieran Michael; Hauffe, Heidi Christine; De Filippo, Carlotta 2015-10-07 The expansion of agriculture is shrinking pristine forest areas worldwide, jeopardizing the persistence of their wild inhabitants. The Udzungwa red colobus monkey (Procolobus gordonorum) is among the most threatened primate species in Africa. Primarily arboreal and highly sensitive to hunting and habitat destruction, they provide a critical model to understanding whether anthropogenic disturbance impacts gut microbiota diversity. We sampled seven social groups inhabiting two forests (disturbed vs. undisturbed) in the Udzungwa Mountains of Tanzania. While Ruminococcaceae and Lachnospiraceae dominated in all individuals, reflecting their role in extracting energy from folivorous diets, analysis of genus composition showed a marked diversification across habitats, with gut microbiota α-diversity significantly higher in the undisturbed forest. Functional analysis suggests that such variation may be associated with food plant diversity in natural versus human-modified habitats, requiring metabolic pathways to digest xenobiotics. Thus, the effects of changes in gut microbiota should not be ignored to conserve endangered populations. 1. Forest conservation, afforestation and reforestation in India: Implications for forest carbon stocks Energy Technology Data Exchange (ETDEWEB) Ravindranath, N.H.; Chaturvedi, R.K.; Murthy, I.K. [Indian Institute of Science, Bangalore (India) 2008-07-25 India is a large developing country with a high population density and low forest area per capita. The livestock population density is among the highest in the world. Further, nearly 70% of the population residing in rural areas depends on forest and other biomass resources for fuel-wood, timber and non-timber forest products for its energy needs and livelihood. In such a socio-economic scenario, one would have expected the forest area to decline, leading to large emissions of CO{sub 2} from the forest sector. The analysis of forest cover, afforestation and reforestation has shown that the forest cover has stabilized in the past 15 years. The progressive conservation-oriented forest policies and afforestation programs are contributing to reduction in CO{sub 2} emissions to the atmosphere, stabilization of carbon stocks in forests and conservation of biodiversity. Thus, the Indian forest sector is projected to keep making positive contributions to global change and sustainable development. This article presents an assessment of the implications of past and current forest conservation and regeneration policies and programs for forest carbon sink in India. The area under forests, including part of the area afforested, is increasing and currently 67.83 mha of area is under forest cover. Assuming that the current trend continues, the area under forest cover is projected to reach 72 mha by 2030. Estimates of carbon stock in Indian forests in both soil and vegetation range from 8.58 to 9.57 GtC. The carbon stock in existing forests is projected to be nearly stable over the next 25 year period at 8.79 GtC. However, if the current rate of afforestation and reforestation is assumed to continue, the carbon stock could increase from 8.79 GtC in 2006 to 9.75 GtC by 2030 -- an increase of 11%. The estimates made in this study assume that the current trend will continue and do not include forest degradation and loss of carbon stock due to biomass extraction, fire, grazing and 2. Profiling unauthorized natural resource users for better targeting of conservation interventions. Science.gov (United States) Harrison, Mariel; Baker, Julia; Twinamatsiko, Medard; Milner-Gulland, E J 2015-12-01 Unauthorized use of natural resources is a key threat to many protected areas. Approaches to reducing this threat include law enforcement and integrated conservation and development (ICD) projects, but for such ICDs to be targeted effectively, it is important to understand who is illegally using which natural resources and why. The nature of unauthorized behavior makes it difficult to ascertain this information through direct questioning. Bwindi Impenetrable National Park, Uganda, has many ICD projects, including authorizing some local people to use certain nontimber forest resources from the park. However, despite over 25 years of ICD, unauthorized resource use continues. We used household surveys, indirect questioning (unmatched count technique), and focus group discussions to generate profiles of authorized and unauthorized resource users and to explore motivations for unauthorized activity. Overall, unauthorized resource use was most common among people from poor households who lived closest to the park boundary and farthest from roads and trading centers. Other motivations for unauthorized resource use included crop raiding by wild animals, inequity of revenue sharing, and lack of employment, factors that created resentment among the poorest communities. In some communities, benefits obtained from ICD were reported to be the greatest deterrents against unauthorized activity, although law enforcement ranked highest overall. Despite the sensitive nature of exploring unauthorized resource use, management-relevant insights into the profiles and motivations of unauthorized resource users can be gained from a combination of survey techniques, as adopted here. To reduce unauthorized activity at Bwindi, we suggest ICD benefit the poorest people living in remote areas and near the park boundary by providing affordable alternative sources of forest products and addressing crop raiding. To prevent resentment from driving further unauthorized activity, ICDs should be 3. Quaternary palaeoecology and nature conservation: a general review with examples from the neotropics Science.gov (United States) Vegas-Vilarrúbia, T.; Rull, V.; Montoya, E.; Safont, E. 2011-09-01 future management policies; 8) the global warming that occurred at the end of the Younger Drays cold reversal (ca 13.0 to 11.5 cal kyr BP) took place at similar rates and magnitudes compared to the global warming projected for the 21st century, thus becoming a powerful past analogue for prediction modelling; 9) environmental changes have acted upon ecosystems in an indirect way by modifying human behaviour and activities that, in turn, have had the potential of changing the environment and enhancing the disturbance effects by synergistic processes involving positive feedbacks; 10) the collapse of past civilisations under climate stress has been chiefly the result of inadequate management procedures and weaknesses in social organisation, which would be a warning for the present uncontrolled growth of human population, the consequent overexploitation of natural resources, and the continuous increase of greenhouse gas emissions; 11) the impact of fire as a decisive ecological agent has increased since the rise of humans, especially during the last millennia, but anthropic fires were not dominant over natural fires until the 19th century; 12) fire has been an essential element in the development and ecological dynamics of many ecosystems, and it has significantly affected the worldwide biome distribution; 13) climate-fire-human synergies that amplify the effects of climate, or fire alone, have been important in the shaping of modern landscapes. These general paleoecological observations and others that have emerged from case studies of particular problems can improve the preservation of biodiversity and ecosystem functions. Nature conservation requires the full consideration of palaeoecological knowledge in an ecological context, along with the synergistic cooperation of palaeoecologists with neoecologists, anthropologists, and conservation scientists. 4. Interactions between nanostructured calcium hydroxide and acrylate copolymers: implications in cultural heritage conservation. Science.gov (United States) Carretti, Emiliano; Chelazzi, David; Rocchigiani, Giulia; Baglioni, Piero; Poggi, Giovanna; Dei, Luigi 2013-08-06 The interactions between an acrylic copolymer, poly ethylmethacrylate/methylacrylate (70:30) (Poly(EMA/MA), and Ca(OH)2 nanoparticles were investigated in order to establish the reciprocal influence of these two compounds on their peculiar properties. The carbonation kinetics of Ca(OH)2 nanoparticles by atmospheric CO2 was investigated by FTIR and SEM measurements and compared to that of a nanocomposite film. CaCO3 formation occurred even in the presence of the copolymer, but only after an induction period of ca. 200 h and with a lower reaction rate. Some implications in cultural heritage conservation dealing with application of nanolime on artifacts previously treated with acrylic copolymers were discussed. Contact angle measurements, mechanical cohesion properties, and water vapor permeability allowed us to conclude that the optimum behavior of nanolime with respect to transpiration was not compromised by the presence of the copolymer, and the behavior in terms of mechanical properties recovery by the application of Ca(OH)2 nanoparticles remained excellent even in the presence of poly(EMA/MA). 5. Hearing sensitivity in context: Conservation implications for a highly vocal endangered species Directory of Open Access Journals (Sweden) Megan A. Owen 2016-04-01 Full Text Available Hearing sensitivity is a fundamental determinant of a species’ vulnerability to anthropogenic noise, however little is known about the hearing capacities of most conservation dependent species. When audiometric data are integrated with other aspects of species’ acoustic ecology, life history, and characteristic habitat topography and soundscape, predictions can be made regarding probable vulnerability to the negative impacts of different types of anthropogenic noise. Here we used an adaptive psychoacoustic technique to measure hearing thresholds in the endangered giant panda; a species that uses acoustic communication to coordinate reproduction. Our results suggest that giant pandas have functional hearing into the ultrasonic range, with good sensitivity between 10.0 and 16.0 kHz, and best sensitivity measured at 12.5–14.0 kHz. We estimated the lower and upper limits of functional hearing as 0.10 and 70.0 kHz respectively. While these results suggest that panda hearing is similar to that of some other terrestrial carnivores, panda hearing thresholds above 14.0 kHz were significantly lower (i.e., more sensitive than those of the polar bear, the only other bear species for which data are available. We discuss the implications of this divergence, as well as the relationship between hearing sensitivity and the spectral parameters of panda vocalizations. We suggest that these data, placed in context, can be used towards the development of a sensory-based model of noise disturbance for the species. 6. Geomorphic and Hydrological challenges in Africa: implications for soil and water conservation Science.gov (United States) Vanmaercke, Matthias; Poesen, Jean 2017-04-01 Expected scenarios of climate change and population growth confront Africa with various important challenges related to food, water and energy security. Many of these challenges are closely linked to the impacts of soil erosion and other geomorphic processes, such as reduced crop yields, sedimentation of reservoirs and reduced freshwater quality. Despite the urgency and extent of many of these challenges, the causes and dynamics of these processes and their impacts remain severely understudied. This becomes apparent when the availability of e.g. soil erosion and catchment sediment export measurements for Africa is compared to that of other continents. Nonetheless, a substantial amount of geomorphic research has been conducted in Africa. Many of this work dates back from several decades ago, and were often only reported in 'gray literature' (e.g. internal reports). Here we present an overview of our current state of knowledge on soil erosion and its implications in Africa. We discuss which geomorphic process rate measurements are currently available and what can be learned from these with respect to the challenged raised above. We especially focus on our current understanding about the effectiveness of soil and water conservation techniques at various spatial and temporal scales. Based on specific case-studies (e.g. in Ethiopia and Uganda) and a meta-analysis of previous work, we highlight some research gaps, research needs and research opportunities when aiming to use Africa's soil and water resources sustainably and efficiently. 7. Tree mortality in mature riparian forest: Implications for Fremont cottonwood conservation in the American southwest Science.gov (United States) Andersen, Douglas 2015-01-01 Mature tree mortality rates are poorly documented in desert riparian woodlands. I monitored deaths and calculated annual survivorship probability (Ps) in 2 groups of large (27–114 cm DBH), old (≥40 years old) Fremont cottonwood (Populus fremontii Wats.) in a stand along the free-flowing Yampa River in semiarid northwestern Colorado. Ps = 0.993 year-1 in a group (n = 126) monitored over 2003–2013, whereas Ps = 0.985 year-1 in a group (n = 179) monitored over the same period plus 3 earlier years (2000–2003) that included drought and a defoliating insect outbreak. Assuming Ps was the same for both groups during the 10-year postdrought period, the data indicate that Ps = 0.958 year-1 during the drought. I found no difference in canopy dieback level between male and female survivors. Mortality was equal among size classes, suggesting Ps is independent of age, but published longevity data imply that either Ps eventually declines with age or, as suggested in this study, periods with high Ps are interrupted by episodes of increased mortality. Stochastic population models featuring episodes of low Ps suggest a potential for an abrupt decline in mature tree numbers where recruitment is low. The modeling results have implications for woodland conservation, especially for relictual stands along regulated desert rivers. 8. Implications of Postharvest Food Loss/Waste Prevention to Energy and Resources Conservation Science.gov (United States) Cai, X.; Shafiee-Jood, M. 2015-12-01 World's growing demand for food is driven by population and income growth, dietary changes, and the ever-increasing competition between food, feed and bioenergy challenges food security; meanwhile agricultural expansion and intensification threats the environment by the various detrimental impacts. Researchers have attempted to explore strategies to overcome this grand challenge. One of the promising solutions that have attracted considerable attention recently is to increase the efficiency of food supply chain by reducing food loss and waste (FLW). According to recent studies conducted by Food and Agriculture Organization (FAO), United Nation, almost one third of the food produced for human consumption globally is lost or wasted along the food supply chain. This amount of food discarded manifests a missing, yet potential, opportunity to sustainably enhance both food security and environmental sustainability. However, implementing the strategies and technologies for tackling FLW does not come up as an easy solution since it requires economic incentives, benefit and cost analysis, infrastructure development, and appropriate market mechanism. In this presentation I will provide a synthesis of knowledge on the implications of postharvest food loss/waste prevention to energy and resource conservation, environmental protection, as well as food security. I will also discuss how traditional civil and environmental engineering can contribute to the reduction of postharvest food loss, an important issue of sustainable agriculture. 9. Hepburn's Natural Aesthetic and Its Implications for Aesthetic Education Science.gov (United States) Yang, Chung-Ping 2013-01-01 The world is rich in natural beauty, and learning how to appreciate the beauty of nature is an important part of aesthetic education. Unfortunately, the teaching of aesthetics is usually restricted to art education, especially in Taiwan. Students' perceptual awareness of and sensitivity to the aesthetics of nature should be cultivated so that… 10. Safety or Salamanders? Natural Hazards and Environmental Conservation in Comprehensive Planning Directory of Open Access Journals (Sweden) Eivind Junker 2014-07-01 Full Text Available The stated purpose of Norwegian land use planning is to promote sustainable development. Environmental considerations are central in the planning process, but have to compete with many other goals and interests. In recent years, complexity, population density and similar factors have made the society more vulnerable. Several major floods, landslides and other natural incidents have raised public awareness about the safety aspect of planning. At the same time, better knowledge about natural systems, including the effects of climate change, have increased the level of uncertainty. In this article, I consider the relation between environmental and safety considerations in planning from a legal perspective. While the examples and theoretical framework are from the Norwegian legal system, the overall analysis is general and, thus, relevant also outside the national jurisdiction. Rather than being opposite and directly competing goals, I argue that safety and conservation can be promoted by the same measures, often with mutual benefits. Thus, the current focus on societal safety can actually enhance the environmental aspect of sustainable development. 11. Feynman Rules in the Type III Natural Flavour-Conserving Two-Higgs Doublet Model CERN Document Server Lin, C; Yang, Y W; Lin, Chilong; Lee, Chien-er; Yang, Yeou-Wei 1994-01-01 We consider a two Higgs-doublet model withS_3$symmetry, which implies a$\\pi \\over 2$rather than 0 relative phase between the vacuum expectation values $$and$$. The corresponding Feynman rules are derived accordingly and the transformation of the Higgs fields from the weak to the mass eigenstates includes not only an angle rotation but also a phase transformation. In this model, both doublets couple to the same type of fermions and the flavour-changing neutral currents are naturally suppressed. We also demonstrate that the Type III natural flavour-conserving model is valid at tree-level even when an explicit$S_3$symmetry breaking perturbation is introduced to get a reasonable CKM matrix. In the special case$\\beta = \\alpha$, as the ratio$\\tan\\beta = {v_2 \\over v_1}$runs from 0 to$\\infty$, the dominant Yukawa coupling will change from the first two generations to the third generation. In the Feynman rules, we also find that the charged Higgs currents are explicitly left-right asymmetric. The ratios ... 12. Mammal diversity and metacommunity dynamics in urban green spaces: implications for urban wildlife conservation. Science.gov (United States) Gallo, Travis; Fidino, Mason; Lehrer, Elizabeth W; Magle, Seth B 2017-08-21 As urban growth expands and natural environments fragment, it is essential to understand the ecological roles fulfilled by urban green spaces. To evaluate how urban green spaces function as wildlife habitat, we estimated mammal diversity and metacommunity dynamics in city parks, cemeteries, golf courses, and natural areas throughout the greater Chicago, IL, USA region. We found similar α-diversity (with the exception of city parks), but remarkably dissimilar communities in different urban green spaces. Additionally, the type of urban green space greatly influenced species colonization and persistence rates. For example, coyotes (Canis latrans) had the highest, but white-tailed deer (Odocoileus virginianus) the lowest, probability of persistence in golf courses compared to other green space types. Further, most species had a difficult time colonizing city parks even when sites were seemingly available. Our results indicate that urban green spaces contribute different, but collectively important, habitats for maintaining and conserving biodiversity in cities. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved. 13. Variability or conservation of hepatitis C virus hypervariable region 1? Implications for immune responses Indian Academy of Sciences (India) Mario U Mondelli; Antonella Cerino; Annalisa Meola; Alfredo Nicosia 2003-04-01 The hypervariable region 1 (HVR1) of the E2 protein of hepatitis C virus (HCV) is highly heterogeneous in its primary sequence and is responsible for significant inter- and intra-individual variation of the infecting virus, which may represent an important pathogenetic mechanism leading to immune escape and persistent infection. A binding site for neutralizing antibodies (Ab) has also been allegedly identified in this region. Prospective studies of serological responses to synthetic oligopeptides derived from naturally-occurring HVR1 sequences showed promiscuous recognition of HVR1 variants in most patients via binding to C-terminal amino acid residues with conserved physicochemical properties. Monoclonal antibodies generated by immunization of mice with peptides derived from natural HVR1 sequences were shown to recognize several HVR1 variants in line with evidence gathered from studies using human sera. In addition, selected mAbs were able to bind HVR1 in the context of a complete soluble form of the E2 glycoprotein, indicating recognition of correctly folded sequences, and were shown to specifically capture circulating and recombinant HCV particles, suggesting that HVR1 is expressed on intact virus particles and therefore potentially able to interact with cellular receptor(s). These findings suggest that it is possible to induce a broadly reactive clonal immune response to multiple HCV variants and that this mechanism could be used in principle to induce protective immunity for a large repertoire of HCV variants. 14. Payments for environmental services and control over conservation of natural resources NARCIS (Netherlands) Rodríguez-de-Francisco, J.C.; Budds, J. 2015-01-01 In Latin America, payment for environmental services (PES) is a tool for watershed conservation that is becoming increasingly promoted by some government agencies, international development organisations and environmental NGOs. However, in pursuit of conservation, PES initiatives implemented at 15. Synthetic biology and conservation of nature: wicked problems and wicked solutions. Science.gov (United States) Redford, Kent H; Adams, William; Mace, Georgina M 2013-01-01 So far, conservation scientists have paid little attention to synthetic biology; this is unfortunate as the technology is likely to transform the operating space within which conservation functions, and therefore the prospects for maintaining biodiversity into the future. 16. Economic efficiency and cost implications of habitat conservation: An example in the context of the Edwards Aquifer region Science.gov (United States) Gillig, Dhazn; McCarl, Bruce A.; Jones, Lonnie L.; Boadu, Frederick 2004-04-01 Groundwater management in the Edwards Aquifer in Texas is in the process of moving away from a traditional right of capture economic regime toward a more environmentally sensitive scheme designed to preserve endangered species habitats. This study explores economic and environmental implications of proposed groundwater management and water development strategies under a proposed regional Habitat Conservation Plan. Results show that enhancing the habitat by augmenting water flow costs$109-1427 per acre-foot and that regional water development would be accelerated by the more extreme possibilities under the Habitat Conservation Plan. The findings also indicate that a water market would improve regional welfare and lower water development but worsen environmental attributes.
17. Using 137Cs technique to quantify soil conservation capacities of different ecosystems in Wolong Natural Reserve, southwestern China
Institute of Scientific and Technical Information of China (English)
GAO Jun; OUYANG ZhiYun
2007-01-01
Reliable information about soil conservation capacities of different natural ecosystems is an important reference for the design of targeted erosion and sediment control strategies. The objective of this paper is to quantify the soil conservation capacities of different natural ecosystems that can represent different climatic zones. The 137Cs technique has been used to estimate soil redistribution rates in different natural ecosystems over the past 40 years in Wolong Nature Reserve. The reserve, transiting from the Chengdu plain to the Qinghai-Tibet plateau, maintains rich ecosystems from subtropical to frigid.The net soil erosion rates of 5 selected ecosystems that represent a warm coniferous-broadleaf-mixed forest, a cold-resistant deciduous taiga forest, a cold-resistant shrub, an evergreen cold-resistant taiga servation capacities are reversed in order. The reference inventories for 137Cs in different ecosystems velop effective erosion and sediment strategies in areas with similar climates should consider natural ecosystem types.
18. Progress and implications from the grazing lands Conservation Effects Assessment Project (CEAP) literature syntheses
Science.gov (United States)
The Conservation Effects Assessment Project (CEAP) is a multiagency effort to quantify scientifically the environmental outcomes of conservation practices used by private landowners. Two syntheses of the scientific literature are underway, which will document the environmental outcomes of conservati...
19. A Selected List of Filmstrips on the Conservation of Natural Resources, Number 5.
Science.gov (United States)
Adams, Jean Larson; Michaud, Howard H.
This pamphlet describes 115 conservation filmstrips as to content, sources, suggested grade level(s), curriculum area(s), and notes of interest to the user. The filmstrips are divided into the following areas: (1) general conservation, (2) ecology and resource interrelationships, (3) forest trees and other plants, (4) forest conservation, (5)…
20. Effects of ship traffic on seabirds in offshore waters: implications for marine conservation and spatial planning.
Science.gov (United States)
Schwemmer, Philipp; Mendel, Bettina; Sonntag, Nicole; Dierschke, Volker; Garthe, Stefan
2011-07-01
Most anthropogenic influences on marine ecosystems, except for river- or terrestrial-borne pollution, involve some sort of vessel activity. Increasing anthropogenic activities mean that many countries are being forced to develop spatial planning schemes, while at the same time implementing conservation sites for sensitive species at sea. The effects of ship traffic on seabirds sensitive to human disturbance are currently too poorly understood to allow for the development of proper planning and conservation guidelines. We therefore used aerial surveys and experimental disturbance to elucidate the effects of passing ships on the distribution patterns, habitat loss, and species-specific flight reactions of birds, as well as the potential for habituation. Loons (Gavia spp.) showed clear avoidance of areas with high shipping intensity. Flush distances of four sea duck species differed significantly, with the longest distances recorded for Common Scoters (Melanitta nigra) and the shortest for Common Eiders (Somateria mollissima). Flush distance was positively related to flock size. Among all the sea duck species studied, the duration of temporary habitat loss was longest for Common Scoters. We found indications of habituation in sea ducks within areas of channeled traffic. However, it is questionable if habituation to free-ranging ships is likely to occur, because of their unpredictable nature. We therefore recommend that spatial planning should aim to channel ship traffic wherever possible to avoid further habitat fragmentation and to allow for habituation, at least in some species. Information on the effects of shipping on other seabird species and during different periods of the year is urgently needed, together with information on the effects of different types of boats, including recreational and fishing vessels.
1. Pre-Holocene Origin for the Coronopus navasii Disjunction: Conservation Implications from Its Long Isolation.
Directory of Open Access Journals (Sweden)
Sara Martín-Hernanz
Full Text Available Integration of unexpected discoveries about charismatic species can disrupt their well-established recovery plans, particularly when this requires coordinate actions among the different governments responsible. The Critically Endangered Coronopus navasii (Brassicaceae was considered a restricted endemism to a few Mediterranean temporary ponds in a high mountain range of Southeast Spain, until a new group of populations were discovered 500 km North in 2006. Ten years after this finding, its management has not been accommodated due to limited information of the new populations and administrative inertia. In this study, DNA sequences and species distribution models are used to analyse the origin of the C. navasii disjunction as a preliminary step to reassess its recovery plan. Molecular results placed the disjunction during Miocene-Pleistocene (6.30-0.49 Mya, plastid DNA; 1.45-0.03 Mya, ribosomal DNA, which discards a putative human-mediated origin. In fact, the haplotype network and the low gene flow estimated between disjunct areas suggest long-term isolation. Dispersal is the most likely explanation for the disjunction as interpreted from the highly fragmented distribution projected to the past. Particularly, a northward dispersal from Southeast is proposed since C. navasii haplotype network is connected to the sister-group through the southern haplotype. Although the reassessment of C. navasii conservation status is more optimistic under the new extent of occurrence, its long-term survival may be compromised due to the: (1 natural fragmentation and rarity of the species habitat, (2 genetic isolation between the two disjunct areas, and (3 northward shift of suitable areas under future climate change scenarios. Several ex-situ and in-situ conservation measures are proposed for integrating Central East Spanish populations into the on-going recovery plan, which still only contemplates Southeast populations and therefore does not preserve the
2. Practical implications of understanding the influence of motivations on commitment to voluntary urban conservation stewardship.
Science.gov (United States)
Asah, Stanley T; Blahna, Dale J
2013-08-01
Although the word commitment is prevalent in conservation biology literature and despite the importance of people's commitment to the success of conservation initiatives, commitment as a psychological phenomenon and its operation in specific conservation behaviors remains unexplored. Despite increasing calls for conservation psychology to play a greater role in meeting conservation goals, applications of the psychological sciences to specific conservation behaviors, illustrating their utility to conservation practice, are rare. We examined conservation volunteers' motivations and commitment to urban conservation volunteering. We interviewed key informant volunteers and used interview findings to develop psychometric scales that we used to assess motivations and commitment to volunteer. We surveyed 322 urban conservation volunteers and used factor analysis to reveal how volunteers structure their motivations and commitment to volunteer for urban conservation activities. Six categories of motivations and 2 categories of commitment emerged from factor analysis. Volunteers were motivated by desires to help the environment, defend and enhance the ego, career and learning opportunities, escape and exercise, social interactions, and community building. Two forms of commitment, affective and normative commitment, psychologically bind people to urban conservation volunteerism. We used linear-regression models to examine how these categories of motivations influence volunteers' commitment to conservation volunteerism. Volunteers' tendency to continue to volunteer for urban conservation, even in the face of fluctuating counter urges, was motivated by personal, social, and community functions more than environmental motivations. The environment, otherwise marginally important, was a significant motivator of volunteers' commitment only when volunteering met volunteers' personal, social, and community-building goals. Attention to these personal, social, and community
3. Kinetics and Mechanism of Calcium Hydroxide Conversion into Calcium Alkoxides: Implications in Heritage Conservation Using Nanolimes.
Science.gov (United States)
Rodriguez-Navarro, Carlos; Vettori, Irene; Ruiz-Agudo, Encarnacion
2016-05-24
important implications in the conservation of cultural heritage.
4. Integrating nature and nurture : Implications of person-environment correlations and interactions for developmental psychopathology
NARCIS (Netherlands)
Rutter, M; Dunn, J; Plomin, R; Simonoff, E; Pickles, A; Maughan, B; Ormel, J; Meyer, J; Eaves, L
1997-01-01
The developmental interplay between nature and nurture is discussed, with particular reference to implications for research in developmental psychopathology. The general principles include individual differences in reactivity to the environment, two-way interplay between intraindividual biology and
5. Biodiversity for billionaires: capitalism, conservation and the role of philanthropy in saving/selling nature.
Science.gov (United States)
Holmes, George
2012-01-01
This article examines the role of philanthropy in conservation as a way of exploring how and why conservation might be becoming more neoliberal. It describes how conservation philanthropy supports capitalism both discursively and in more practical ways. Philanthropy is examined in terms of the two forces considered to be driving the neoliberalization of conservation — the need for capitalism to find new ways of making money, and the desire of conservationists to engage with capitalism as the best way of getting things done. It demonstrates how philanthropy can speak to both of these logics simultaneously, particularly through emerging ideas of philanthrocapitalism, which may be enhancing the neoliberalization of both philanthropy and conservation.
6. Freshwater Wetland Habitat Loss and Fragmentation: Implications for Aquatic Biodiversity Conservation
Science.gov (United States)
Wolaver, B. D.; Pierre, J. P.; Labay, B. J.; Ryberg, W. A.; Hibbits, T. J.; Prestridge, H. L.
2015-12-01
Anthropogenic land use changes have caused widespread wetland loss and fragmentation. This trend has important implications for aquatic biota conservation, including the semi-aquatic Western Chicken Turtle (Deirochelys reticularia miaria). This species inhabits seasonally inundated, ephemeral water bodies and adjacent uplands in the southeastern U.S. However, wetland conversion to agriculture and urbanization is thought to cause the species' decline, particularly in Texas, which includes the westernmost part of its range. Because the species moves only a few kilometers between wetlands, it particularly sensitive to habitat loss and fragmentation. Thus, as part of the only state-funded species research program, this study provides the U.S. Fish and Wildlife Service (FWS) with scientific data to determine if the species warrants protection under the Endangered Species Act (ESA). We use a species distribution model to map potentially suitable habitat for most of East Texas. We evaluate landscape-scale anthropogenic activities in this region which may be contributing to the species' decline. We identify areas of urbanization, agricultural expansion, forestry, and resulting wetland loss. We find that between 2001 and 2011 approximately 80 km2 of wetlands were lost in potentially suitable habitat, including the urbanizing Houston area. We use spatial geostatistics to quantify wetland habitat fragmentation. We also introduce the Habitat Alteration Index (HAI), which calculates total landscape alteration and mean probability of occurrence to identify high-quality habitat most at risk of recent anthropogenic alteration. Population surveys by biologists are targeting these areas and future management actions may focus on mitigating anthropogenic activities there. While this study focuses on D. r. miaria, this approach can evaluate wetland habitat of other aquatic organisms.
7. Conservation assessment of current and proposed nature reserves of Tamaulipas state, Mexico
Science.gov (United States)
Cantu, C.; Gerald, Wright R.; Michael, Scott J.; Strand, Espen
2003-01-01
The Mexican state of Tamaulipas located in the northeastern portion of the country currently has five state nature reserves covering slightly less than 3% of its land area. These reserves were established for a variety of reasons, many unrelated to the protection of biological resources. In 2000 in response to a growing concern about the lack of organized conservation reserve planning to protect the important biological and physical features of Mexico, the Mexican Commission for Knowledge and Use of Biodiversity (CONABIO) proposed 13 new terrestrial reserves for Tamaulipas. If established these new reserves would increase the proportion of terrestrial protected lands in the state to over 21%. We compiled a geographic information system (GIS) using existing digital thematic maps of physical and biological features to examine how the existing and proposed reserves might serve to protect the biodiversity and physical features of the state. We found that most of the existing protected sites occur in areas with elevations > 1000-2000 m with temperate climate and dominated by pine forest, oak forest, and cloud forest vegetation cover types. The state's dominant biotic region - low elevation coastal plain with tropical and arid climate types and xeric scrub vegetation - is disproportionately underrepresented in the current reserve system. The creation of the proposed areas would substantially increase the protection of mid and high elevation lands. The largest gap in the protected lands network would be low elevation, level, coastal lands.
8. Major Vegetation Types of the Soutpansberg Conservancy and the Blouberg Nature Reserve, South Africa
Directory of Open Access Journals (Sweden)
Theo H.C. Mostert
2008-05-01
Full Text Available The Major Megetation Types (MVT and plant communities of the Soutpansberg Centre of Endemism are described in detail, with special reference to the Soutpansberg Conservancy and the Blouberg Nature Reserve. Phytosociological data from 442 sample plots were ordinated using a DEtrended CORrespondence ANAlysis (DECORANA and classified using TWo-Way INdicator SPecies ANalysis (TWINSPAN. The resulting classification was further refined with table-sorting procedures based on the Braun–Blanquet floristic–sociological approach of vegetation classification using MEGATAB. Eight MVT’s were identified and described as Eragrostis lehmanniana var. lehmanniana–Sclerocarya birrea subsp. caffra Blouberg Northern Plains Bushveld, Euclea divinorum–Acacia tortilis Blouberg Southern Plains Bushveld, Englerophytum magalismontanum–Combretum molle Blouberg Mountain Bushveld, Adansonia digitata–Acacia nigrescens Soutpansberg Arid Northern Bushveld, Catha edulis–Flueggia virosa Soutpansberg Moist Mountain Thickets, Diplorhynchus condylocarpon–Burkea africana Soutpansberg Leached Sandveld, Rhus rigida var. rigida–Rhus magalismontanum subsp. coddii Soutpansberg Mistbelt Vegetation and Xymalos monospora–Rhus chirendensis Soutpansberg Forest Vegetation.
9. Spatiotemporal dynamics of surface water networks across a global biodiversity hotspot—implications for conservation
Science.gov (United States)
Tulbure, Mirela G.; Kininmonth, Stuart; Broich, Mark
2014-11-01
The concept of habitat networks represents an important tool for landscape conservation and management at regional scales. Previous studies simulated degradation of temporally fixed networks but few quantified the change in network connectivity from disintegration of key features that undergo naturally occurring spatiotemporal dynamics. This is particularly of concern for aquatic systems, which typically show high natural spatiotemporal variability. Here we focused on the Swan Coastal Plain, a bioregion that encompasses a global biodiversity hotspot in Australia with over 1500 water bodies of high biodiversity. Using graph theory, we conducted a temporal analysis of water body connectivity over 13 years of variable climate. We derived large networks of surface water bodies using Landsat data (1999-2011). We generated an ensemble of 278 potential networks at three dispersal distances approximating the maximum dispersal distance of different water dependent organisms. We assessed network connectivity through several network topology metrics and quantified the resilience of the network topology during wet and dry phases. We identified ‘stepping stone’ water bodies across time and compared our networks with theoretical network models with known properties. Results showed a highly dynamic seasonal pattern of variability in network topology metrics. A decline in connectivity over the 13 years was noted with potential negative consequences for species with limited dispersal capacity. The networks described here resemble theoretical scale-free models, also known as ‘rich get richer’ algorithm. The ‘stepping stone’ water bodies are located in the area around the Peel-Harvey Estuary, a Ramsar listed site, and some are located in a national park. Our results describe a powerful approach that can be implemented when assessing the connectivity for a particular organism with known dispersal distance. The approach of identifying the surface water bodies that act as
10. Wild meat consumption on São Tomé Island, West Africa: implications for conservation and local livelihoods
Directory of Open Access Journals (Sweden)
Mariana Carvalho
2015-09-01
Full Text Available The importance of wild meats for rural people is well documented in tropical forests worldwide. However, the case of oceanic islands remains relatively poorly studied. We assess the contribution made by wild meats to the diets of rural inhabitants in the Island of São Tomé, characterize the relative importance of native and introduced fauna, and discuss the implications of wild meat consumption on rural livelihoods and on the conservation of the resident fauna. Using semistructured interviews, we assessed animal protein consumption in 10 communities (716 household-weeks, around the vicinity of the island's main protected area, Obô Natural Park. Fish and the introduced West African giant snail (Archachatina marginata are the most important sources of protein for rural inhabitants, with wild terrestrial vertebrates being consumed by only a small fraction of sampled households. Significantly higher amounts of wild snail and wild mammal meat are consumed in more remote areas with poorer families depending more on snails, and richer households on fruit bats or introduced mammals. Although eaten in relatively small numbers per household, consumption of wild birds is widespread, thus when extrapolated to the island's entire rural population, this practice is likely to be unsustainable, particularly for endemic pigeons that are also commercially hunted. Our results suggest that rural populations in São Tomé largely depend on protein from introduced wild species, with native and endemic fauna constituting less important sources. However, endemic birds and native fruit bats are extensively harvested for household consumption and constitute a commonly used resource that urgently needs to be regulated.
11. Genetic variability and population structure of Salvia lachnostachys: implications for breeding and conservation programs.
Science.gov (United States)
Erbano, Marianna; Schühli, Guilherme Schnell E; Santos, Élide Pereira Dos
2015-04-08
The genetic diversity and population structure of Salvia lachnostachys Benth were assessed. Inter Simple Sequence Repeat (ISSR) molecular markers were used to investigate the restricted distribution of S. lachnostachys in Parana State, Brazil. Leaves of 73 individuals representing three populations were collected. DNA was extracted and submitted to PCR-ISSR amplification with nine tested primers. Genetic diversity parameters were evaluated. Our analysis indicated 95.6% polymorphic loci (stress value 0.02) with a 0.79 average Simpson's index. The Nei-Li distance dendrogram and principal component analysis largely recovered the geographical origin of each sample. Four major clusters were recognized representing each collected population. Nei's gene diversity and Shannon's information index were 0.25 and 0.40 respectively. As is typical for outcrossing herbs, the majority of genetic variation occurred at the population level (81.76%). A high gene flow (Nm = 2.48) was observed with a correspondingly low fixation index. These values were generally similar to previous studies on congeneric species. The results of principal coordinate analysis (PCA) and of arithmetic average (UPGMA) were consistent and all three populations appear distinct as in STRUCTURE analysis. In addition, this analysis indicated a majority intrapopulation genetic variation. Despite the human pressure on natural populations our study found high levels of genetic diversity for S. lachnostachys. This was the first molecular assessment for this endemic species with medicinal proprieties and the results can guide for subsequent bioprospection, breeding programs or conservation actions.
12. Seed storage and testing at Pennsylvania Department of Conservation and Natural Resources Penn Nursery and Wood Shop
Science.gov (United States)
Jeffrey J. Kozar
2008-01-01
Planting tree seeds at the Pennsylvania Department of Conservation and Natural Resources Penn Nursery, Spring Mills, Pennsylvania occurs in spring and fall. Seeds acquired for these plantings come from 3 sources. The first source is our own orchards, which were developed to provide âimprovedâ seeds. Improved seeds are produced from scion material collected from trees...
13. A 2.5-million-year perspective on coarse-filter strategies for conserving nature's stage.
Science.gov (United States)
Gill, Jacquelyn L; Blois, Jessica L; Benito, Blas; Dobrowski, Solomon; Hunter, Malcolm L; McGuire, Jenny L
2015-06-01
Climate change will require novel conservation strategies. One such tactic is a coarse-filter approach that focuses on conserving nature's stage (CNS) rather than the actors (individual species). However, there is a temporal mismatch between the long-term goals of conservation and the short-term nature of most ecological studies, which leaves many assumptions untested. Paleoecology provides a valuable perspective on coarse-filter strategies by marshaling the natural experiments of the past to contextualize extinction risk due to the emerging impacts of climate change and anthropogenic threats. We reviewed examples from the paleoecological record that highlight the strengths, opportunities, and caveats of a CNS approach. We focused on the near-time geological past of the Quaternary, during which species were subjected to widespread changes in climate and concomitant changes in the physical environment in general. Species experienced a range of individualistic responses to these changes, including community turnover and novel associations, extinction and speciation, range shifts, changes in local richness and evenness, and both equilibrium and disequilibrium responses. Due to the dynamic nature of species responses to Quaternary climate change, a coarse-filter strategy may be appropriate for many taxa because it can accommodate dynamic processes. However, conservationists should also consider that the persistence of landforms varies across space and time, which could have potential long-term consequences for geodiversity and thus biodiversity. © 2015 Society for Conservation Biology.
14. Consuming the forest in an environment of crisis: nature tourism, forest conservation and neoliberal agriculture in south India.
Science.gov (United States)
Münster, Daniel; Münster, Ursula
2012-01-01
This article engages ethnographically with the neoliberalization of nature in the spheres of tourism, conservation and agriculture. Drawing on a case study of Wayanad district, Kerala, the article explores a number of themes. First, it shows how a boom in domestic nature tourism is currently transforming Wayanad into a landscape for tourist consumption. Second, it examines how tourism in Wayanad articulates with projects of neoliberalizing forest and wildlife conservation and with their contestations by subaltern groups. Third, it argues that the contemporary commodification of nature in tourism and conservation is intimately related to earlier processes of commodifying nature in agrarian capitalism. Since independence, forest land has been violently appropriated for intensive cash-cropping. Capitalist agrarian change has transformed land into a (fictitious) commodity and produced a fragile and contested frontier of agriculture and wildlife. When agrarian capitalism reached its ecological limits and entered a crisis of accumulation, farming became increasingly speculative, exploring new modes of accumulation in out-of-state ginger cultivation. In this scenario nature and wildlife tourism emerges as a new prospect for accumulation in a post-agrarian economy. The neoliberalization of nature in Wayanad, the authors argue, is a process driven less by new modes of regulation than by the agrarian crisis and new modes of speculative farming.
15. Beyond Nature Appropriation: Towards Post-development Conservation in the Maya Forest
Directory of Open Access Journals (Sweden)
Jose E Martinez-Reyes
2014-01-01
Full Text Available The establishment of biosphere reserves in Mexico was followed by alternative livelihood conservation/development projects to integrate indigenous groups into Western style conservation under the idea of sustainable development and participation. In this paper, I discuss the outcomes of two forest wildlife management projects in one Maya community along the Sian Ka′an Biosphere Reserve in the state of Quintana Roo. Both projects ultimately failed and the community mobilised and expelled the NGO from the community. I argue that the failure of these projects involved two dynamics: 1 lack of coherence between the objectives of state agencies, conservation NGOs, and the local community; and 2 unequal ethnic relations, reproducing relations of colonial inequality and dictating how indigenous groups can participate in managing a territory for conservation. If collaboration and local participation are key in conservation management programs, these case studies suggest that greater institutional accountability and community autonomy are needed to make the practice of conservation more democratic and participatory. The expulsion of the NGO as a conservation and development broker also opened the space for, and possibilities of, post-development conservation practice that challenges the normalising expectations of Western biodiversity conservation.
16. Trophy Hunting, Conservation, and Rural Development in Zimbabwe: Issues, Options, and Implications
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Victor K. Muposhi
2016-01-01
Full Text Available Trophy hunting has potential to support conservation financing and contribute towards rural development. We conducted a systematic review of the Zimbabwean trophy hunting perspective spanning from pre-1890 to 2015, by examining the following: (1 evolution of legal instruments, administration, and governance of trophy hunting, (2 significance of trophy hunting in conservation financing and rural development, and (3 key challenges, emerging issues in trophy hunting industry, and future interventions. Our review shows that (i there has been a constant evolution in the policies related to trophy hunting and conservation in Zimbabwe as driven by local and international needs; (ii trophy hunting providing incentives for wildlife conservation (e.g., law enforcement and habitat protection and rural communities’ development. Emerging issues that may affect trophy hunting include illegal hunting, inadequate monitoring systems, and hunting bans. We conclude that trophy hunting is still relevant in wildlife conservation and rural communities’ development especially in developing economies where conservation financing is inadequate due to fiscal constraints. We recommend the promotion of net conservation benefits for positive conservation efforts and use of wildlife conservation credits for the opportunity costs associated with reducing trophy hunting off-take levels and promoting nonconsumptive wildlife use options.
17. Threshold concepts: implications for the management of natural resources
Science.gov (United States)
Guntenspergen, Glenn R.; Gross, John
2014-01-01
Threshold concepts can have broad relevance in natural resource management. However, the concept of ecological thresholds has not been widely incorporated or adopted in management goals. This largely stems from the uncertainty revolving around threshold levels and the post hoc analyses that have generally been used to identify them. Natural resource managers have a need for new tools and approaches that will help them assess the existence and detection of conditions that demand management actions. Recognition of additional threshold concepts include: utility thresholds (which are based on human values about ecological systems) and decision thresholds (which reflect management objectives and values and include ecological knowledge about a system) as well as ecological thresholds. All of these concepts provide a framework for considering the use of threshold concepts in natural resource decision making.
18. Synthetic biology and conservation of nature: wicked problems and wicked solutions.
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Kent H Redford
Full Text Available So far, conservation scientists have paid little attention to synthetic biology; this is unfortunate as the technology is likely to transform the operating space within which conservation functions, and therefore the prospects for maintaining biodiversity into the future.
19. Payments for environmental services and control over conservation of natural resources
NARCIS (Netherlands)
Rodríguez-de-Francisco, J.C.; Budds, J.
2015-01-01
In Latin America, payment for environmental services (PES) is a tool for watershed conservation that is becoming increasingly promoted by some government agencies, international development organisations and environmental NGOs. However, in pursuit of conservation, PES initiatives implemented at t
20. Global mega forces: Implications for the future of natural resources
Science.gov (United States)
George H. Kubik
2012-01-01
The purpose of this paper is to provide an overview of leading global mega forces and their importance to the future of natural resource decisionmaking, policy development, and operation. Global mega forces are defined as a combination of major trends, preferences, and probabilities that come together to produce the potential for future high-impact outcomes. These...
1. Conserved immune recognition hierarchy of mycobacterial PE/PPE proteins during infection in natural hosts.
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H Martin Vordermeier
Full Text Available The Mycobacterium tuberculosis genome contains two large gene families encoding proteins of unknown function, characterized by conserved N-terminal proline and glutamate (PE and PPE motifs. The presence of a large number of PE/PPE proteins with repetitive domains and evidence of strain variation has given rise to the suggestion that these proteins may play a role in immune evasion via antigenic variation, while emerging data suggests that some family members may play important roles in mycobacterial pathogenesis. In this study, we examined cellular immune responses to a panel of 36 PE/PPE proteins during human and bovine infection. We observed a distinct hierarchy of immune recognition, reflected both in the repertoire of PE/PPE peptide recognition in individual cows and humans and in the magnitude of IFN-γ responses elicited by stimulation of sensitized host cells. The pattern of immunodominance was strikingly similar between cattle that had been experimentally infected with Mycobacterium bovis and humans naturally infected with clinical isolates of M. tuberculosis. The same pattern was maintained as disease progressed throughout a four-month course of infection in cattle, and between humans with latent as well as active tuberculosis. Detailed analysis of PE/PPE responses at the peptide level suggests that antigenic cross-reactivity amongst related family members is a major determinant in the observed differences in immune hierarchy. Taken together, these results demonstrate that a subset of PE/PPE proteins are major targets of the cellular immune response to tuberculosis, and are recognized at multiple stages of infection and in different disease states. Thus this work identifies a number of novel antigens that could find application in vaccine development, and provides new insights into PE/PPE biology.
2. Using 137Cs technique to quantify soil conservation capacities of different ecosystems in Wolong Natural Reserve, southwestern China
Institute of Scientific and Technical Information of China (English)
2007-01-01
Reliable information about soil conservation capacities of different natural ecosystems is an important reference for the design of targeted erosion and sediment control strategies. The objective of this paper is to quantify the soil conservation capacities of different natural ecosystems that can represent dif-ferent climatic zones. The 137Cs technique has been used to estimate soil redistribution rates in differ-ent natural ecosystems over the past 40 years in Wolong Nature Reserve. The reserve, transiting from the Chengdu plain to the Qinghai-Tibet plateau, maintains rich ecosystems from subtropical to frigid. The net soil erosion rates of 5 selected ecosystems that represent a warm coniferous-broadleaf-mixed forest, a cold-resistant deciduous taiga forest, a cold-resistant shrub, an evergreen cold-resistant taiga forest, and an alpine meadow are 0.17, 0.16, 0.13, 0.11 and 0.06 kg·m-2·a-1, respectively. Their soil con-servation capacities are reversed in order. The reference inventories for 137Cs in different ecosystems range from 1658 to 3707 Bq·m-2 with the altitude. Results of this study indicate that any attempt to de-velop effective erosion and sediment strategies in areas with similar climates should consider natural ecosystem types.
3. Using 137Cs technique to quantify soil conservation capacities of different ecosystems in Wolong Natural Reserve, southwestern China.
Science.gov (United States)
Gao, Jun; Ouyang, ZhiYun
2007-08-01
Reliable information about soil conservation capacities of different natural ecosystems is an important reference for the design of targeted erosion and sediment control strategies. The objective of this paper is to quantify the soil conservation capacities of different natural ecosystems that can represent different climatic zones. The (137)Cs technique has been used to estimate soil redistribution rates in different natural ecosystems over the past 40 years in Wolong Nature Reserve. The reserve, transiting from the Chengdu plain to the Qinghai-Tibet plateau, maintains rich ecosystems from subtropical to frigid. The net soil erosion rates of 5 selected ecosystems that represent a warm coniferous-broadleaf-mixed forest, a cold-resistant deciduous taiga forest, a cold-resistant shrub, an evergreen cold-resistant taiga forest, and an alpine meadow are 0.17, 0.16, 0.13, 0.11 and 0.06 kg x m(-2) x a(-1), respectively. Their soil conservation capacities are reversed in order. The reference inventories for (137)Cs in different ecosystems range from 1658 to 3707 Bq x m(-2) with the altitude. Results of this study indicate that any attempt to develop effective erosion and sediment strategies in areas with similar climates should consider natural ecosystem types.
4. A multilingual/multicultural semantic-based approach to improve Data Sharing in an SDI for Nature Conservation
CERN Document Server
De Martino, Monica; 10.2902/1725-0463.2011.06.art10
2011-01-01
The paper proposes an approach to transcend multicultural and multilingual barriers in the use and reuse of geographical data at the European level. The approach aims at sharing scientific terms in the field of nature conservation with the goal of assisting different user communities with metadata compilation and information discovery. A multi-thesauri solution is proposed, based on a Common Thesaurus Framework for Nature Conservation, where different well-known Knowledge Organization Systems are assembled and shared. It has been designed according to semantic web and W3C recommendations employing SKOS standard models and Linked Data to publish the thesauri as a whole in machine-understandable format. The outcome is a powerful framework satisfying the requirements of modularity and openness for further thesaurus extension and updating, interlinking among thesauri, and exploitability from other systems. The paper supports the employment of Linked Data to deal with terminologies in complex domains such as natur...
5. Diverse Early Life-History Strategies in Migratory Amazonian Catfish: Implications for Conservation and Management.
Directory of Open Access Journals (Sweden)
Jens C Hegg
the geology of the upstream watershed to the Sr isotope ratio. Our results provide the first reported otolith microchemical reconstruction of Brachyplatystoma migratory movements in the Amazon Basin. Our results indicate that juveniles exhibit diverse rearing strategies, rearing in both upstream and estuary environments. This contrasts with the prevailing understanding that juveniles rear in the estuary before migrating upstream; however, it is supported by some fisheries data that has indicated the presence of alternate spawning and rearing life-histories. The presence of alternate juvenile rearing strategies may have important implications for conservation and management of the fisheries in the region.
6. Effects of wolves on elk and cattle behaviors: implications for livestock production and wolf conservation.
Directory of Open Access Journals (Sweden)
Isabelle Laporte
Full Text Available BACKGROUND: In many areas, livestock are grazed within wolf (Canis lupus range. Predation and harassment of livestock by wolves creates conflict and is a significant challenge for wolf conservation. Wild prey, such as elk (Cervus elaphus, perform anti-predator behaviors. Artificial selection of cattle (Bos taurus might have resulted in attenuation or absence of anti-predator responses, or in erratic and inconsistent responses. Regardless, such responses might have implications on stress and fitness. METHODOLOGY/PRINCIPAL FINDINGS: We compared elk and cattle anti-predator responses to wolves in southwest Alberta, Canada within home ranges and livestock pastures, respectively. We deployed satellite- and GPS-telemetry collars on wolves, elk, and cattle (n = 16, 10 and 78, respectively and measured seven prey response variables during periods of wolf presence and absence (speed, path sinuosity, time spent head-up, distance to neighboring animals, terrain ruggedness, slope and distance to forest. During independent periods of wolf presence (n = 72, individual elk increased path sinuosity (Z = -2.720, P = 0.007 and used more rugged terrain (Z = -2.856, P = 0.004 and steeper slopes (Z = -3.065, P = 0.002. For cattle, individual as well as group behavioral analyses were feasible and these indicated increased path sinuosity (Z = -2.720, P = 0.007 and decreased distance to neighbors (Z = -2.551, P = 0.011. In addition, cattle groups showed a number of behavioral changes concomitant to wolf visits, with variable direction in changes. CONCLUSIONS/SIGNIFICANCE: Our results suggest both elk and cattle modify their behavior in relation to wolf presence, with potential energetic costs. Our study does not allow evaluating the efficacy of anti-predator behaviors, but indicates that artificial selection did not result in their absence in cattle. The costs of wolf predation on livestock are often compensated considering just the market value of the animal killed
7. Genetic Variability and Population Structure of Salvia lachnostachys: Implications for Breeding and Conservation Programs
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Marianna Erbano
2015-04-01
Full Text Available The genetic diversity and population structure of Salvia lachnostachys Benth were assessed. Inter Simple Sequence Repeat (ISSR molecular markers were used to investigate the restricted distribution of S. lachnostachys in Parana State, Brazil. Leaves of 73 individuals representing three populations were collected. DNA was extracted and submitted to PCR-ISSR amplification with nine tested primers. Genetic diversity parameters were evaluated. Our analysis indicated 95.6% polymorphic loci (stress value 0.02 with a 0.79 average Simpson’s index. The Nei-Li distance dendrogram and principal component analysis largely recovered the geographical origin of each sample. Four major clusters were recognized representing each collected population. Nei’s gene diversity and Shannon’s information index were 0.25 and 0.40 respectively. As is typical for outcrossing herbs, the majority of genetic variation occurred at the population level (81.76%. A high gene flow (Nm = 2.48 was observed with a correspondingly low fixation index. These values were generally similar to previous studies on congeneric species. The results of principal coordinate analysis (PCA and of arithmetic average (UPGMA were consistent and all three populations appear distinct as in STRUCTURE analysis. In addition, this analysis indicated a majority intrapopulation genetic variation. Despite the human pressure on natural populations our study found high levels of genetic diversity for S. lachnostachys. This was the first molecular assessment for this endemic species with medicinal proprieties and the results can guide for subsequent bioprospection, breeding programs or conservation actions.
8. Interactions Between Spatially Explicit Conservation and Management Measures: Implications for the Governance of Marine Protected Areas
Science.gov (United States)
Cárcamo, P. Francisco; Gaymer, Carlos F.
2013-12-01
Marine protected areas are not established in an institutional and governance vacuum and managers should pay attention to the wider social-ecological system in which they are immersed. This article examines Islas Choros-Damas Marine Reserve, a small marine protected area located in a highly productive and biologically diverse coastal marine ecosystem in northern Chile, and the interactions between human, institutional, and ecological dimensions beyond those existing within its boundaries. Through documents analysis, surveys, and interviews, we described marine reserve implementation (governing system) and the social and natural ecosystem-to-be-governed. We analyzed the interactions and the connections between the marine reserve and other spatially explicit conservation and/or management measures existing in the area and influencing management outcomes and governance. A top-down approach with poor stakeholder involvement characterized the implementation process. The marine reserve is highly connected with other spatially explicit measures and with a wider social-ecological system through various ecological processes and socio-economic interactions. Current institutional interactions with positive effects on the management and governance are scarce, although several potential interactions may be developed. For the study area, any management action must recognize interferences from outside conditions and consider some of them (e.g., ecotourism management) as cross-cutting actions for the entire social-ecological system. We consider that institutional interactions and the development of social networks are opportunities to any collective effort aiming to improve governance of Islas Choros-Damas marine reserve. Communication of connections and interactions between marine protected areas and the wider social-ecological system (as described in this study) is proposed as a strategy to improve stakeholder participation in Chilean marine protected areas.
9. Conservation of intron and intein insertion sites: implications for life histories of parasitic genetic elements
Directory of Open Access Journals (Sweden)
Senejani Alireza G
2009-12-01
Full Text Available Abstract Background Inteins and introns are genetic elements that are removed from proteins and RNA after translation or transcription, respectively. Previous studies have suggested that these genetic elements are found in conserved parts of the host protein. To our knowledge this type of analysis has not been done for group II introns residing within a gene. Here we provide quantitative statistical support from an analyses of proteins that host inteins, group I introns, group II introns and spliceosomal introns across all three domains of life. Results To determine whether or not inteins, group I, group II, and spliceosomal introns are found preferentially in conserved regions of their respective host protein, conservation profiles were generated and intein and intron positions were mapped to the profiles. Fisher's combined probability test was used to determine the significance of the distribution of insertion sites across the conservation profile for each protein. For a subset of studied proteins, the conservation profile and insertion positions were mapped to protein structures to determine if the insertion sites correlate to regions of functional activity. All inteins and most group I introns were found to be preferentially located within conserved regions; in contrast, a bacterial intein-like protein, group II and spliceosomal introns did not show a preference for conserved sites. Conclusions These findings demonstrate that inteins and group I introns are found preferentially in conserved regions of their respective host proteins. Homing endonucleases are often located within inteins and group I introns and these may facilitate mobility to conserved regions. Insertion at these conserved positions decreases the chance of elimination, and slows deletion of the elements, since removal of the elements has to be precise as not to disrupt the function of the protein. Furthermore, functional constrains on the targeted site make it more difficult
10. Verbal explanations given by science teachers: Their nature and implications
Science.gov (United States)
Dagher, Zoubeida; Cossman, George
The purpose of this study was to explore the nature of explanations used by science teachers in junior high school classrooms. Studies on explanation in education, philosophy of science, and everyday discourse were consulted. Twenty public school teachers participated in the study. The analysis was based on observations of 40 class periods during which the classroom discourse was audiotaped and later transcribed. Using the constant comparative method in analyzing the transcripts, 10 types of explanations were generated. These explanations were labeled analogical, anthropomorphic, functional, genetic, mechanical, metaphysical, practical, rational, tautological, and teleological. These 10 types were conceptually related to one another by subsuming them under more encompassing literature-based categories.
11. Internet-Based Approaches to Building Stakeholder Networks for Conservation and Natural Resource Management.
Science.gov (United States)
Social network analysis (SNA) is based on a conceptual network representation of social interactions and is an invaluable tool for conservation professionals to increase collaboration, improve information flow, and increase efficiency. We present two approaches to constructing in...
12. Poverty, livelihoods and the conservation of nature in biodiversity hotspots around the world
CSIR Research Space (South Africa)
Bouma, J
2013-01-01
Full Text Available The high incidence of poverty in biodiversity hotspots around the world has given rise to a debate about the potential of integrated development-conservation approaches to help alleviate poverty and protect biodiversity at the same time...
13. Internet-Based Approaches to Building Stakeholder Networks for Conservation and Natural Resource Management.
Science.gov (United States)
Social network analysis (SNA) is based on a conceptual network representation of social interactions and is an invaluable tool for conservation professionals to increase collaboration, improve information flow, and increase efficiency. We present two approaches to constructing in...
14. The Embodied Nature of Autistic Learning: Implications for Physical Education
Directory of Open Access Journals (Sweden)
Jespersen Ejgil
2015-03-01
Full Text Available Autism spectrum disorder (ASD and learning difficulties are difficult to separate in clinic manifestations and diagnoses. By taking learning as being-in-the-world, this article considers the embodied nature of autistic learning and urges its importance for understanding the phenomenological core of ASD. We begin by arguing that three mainstream contemporary ASD theories are inherently limited in offering an adequate account of autistic learning due to the disembodied ontology inscribed within them. Then, we provide an understanding of learning guided by the subjective dynamics of experience. Instead of having a disembodied and individualistic point of view, we suggest that autistic learning has an embodied nature. The “inappropriate” or “abnormal” affections and behaviors in the autistic experience of learning may actually be inherently meaningful for individuals with ASD. They strive to make sense of some basic disturbances and re-establish some form of coherence with the world, though this may only be possible in the form of delusions or autistic withdrawals. Finally, we explore the relationship between autistic learning and physical education and suggest in particular how spontaneous imitation can boost the development of children with ASD. We conclude that the application of implicit learning strategies in playful settings and the reduction of explicit strategies based upon intellectual reasoning rather than bodily reciprocity should be encouraged in the process of autistic learning.
15. Superior control of HIV-1 replication by CD8+ T cells targeting conserved epitopes: implications for HIV vaccine design.
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Pratima Kunwar
Full Text Available A successful HIV vaccine will likely induce both humoral and cell-mediated immunity, however, the enormous diversity of HIV has hampered the development of a vaccine that effectively elicits both arms of the adaptive immune response. To tackle the problem of viral diversity, T cell-based vaccine approaches have focused on two main strategies (i increasing the breadth of vaccine-induced responses or (ii increasing vaccine-induced responses targeting only conserved regions of the virus. The relative extent to which set-point viremia is impacted by epitope-conservation of CD8(+ T cell responses elicited during early HIV-infection is unknown but has important implications for vaccine design. To address this question, we comprehensively mapped HIV-1 CD8(+ T cell epitope-specificities in 23 ART-naïve individuals during early infection and computed their conservation score (CS by three different methods (prevalence, entropy and conseq on clade-B and group-M sequence alignments. The majority of CD8(+ T cell responses were directed against variable epitopes (p<0.01. Interestingly, increasing breadth of CD8(+ T cell responses specifically recognizing conserved epitopes was associated with lower set-point viremia (r = - 0.65, p = 0.009. Moreover, subjects possessing CD8(+ T cells recognizing at least one conserved epitope had 1.4 log10 lower set-point viremia compared to those recognizing only variable epitopes (p = 0.021. The association between viral control and the breadth of conserved CD8(+ T cell responses may be influenced by the method of CS definition and sequences used to determine conservation levels. Strikingly, targeting variable versus conserved epitopes was independent of HLA type (p = 0.215. The associations with viral control were independent of functional avidity of CD8(+ T cell responses elicited during early infection. Taken together, these data suggest that the next-generation of T-cell based HIV-1 vaccines should focus
16. The need to respect nature and its limits challenges society and conservation science.
Science.gov (United States)
Martin, Jean-Louis; Maris, Virginie; Simberloff, Daniel S
2016-05-31
Increasing human population interacts with local and global environments to deplete biodiversity and resources humans depend on, thus challenging societal values centered on growth and relying on technology to mitigate environmental stress. Although the need to address the environmental crisis, central to conservation science, generated greener versions of the growth paradigm, we need fundamental shifts in values that ensure transition from a growth-centered society to one acknowledging biophysical limits and centered on human well-being and biodiversity conservation. We discuss the role conservation science can play in this transformation, which poses ethical challenges and obstacles. We analyze how conservation and economics can achieve better consonance, the extent to which technology should be part of the solution, and difficulties the "new conservation science" has generated. An expanded ambition for conservation science should reconcile day-to-day action within the current context with uncompromising, explicit advocacy for radical transitions in core attitudes and processes that govern our interactions with the biosphere. A widening of its focus to understand better the interconnectedness between human well-being and acknowledgment of the limits of an ecologically functional and diverse planet will need to integrate ecological and social sciences better. Although ecology can highlight limits to growth and consequences of ignoring them, social sciences are necessary to diagnose societal mechanisms at work, how to correct them, and potential drivers of social change.
17. Diversity in soil seed bank of Sinai and implications for conservation ...
African Journals Online (AJOL)
Key words: Sinai, soil seed bank, arid environments, diversity indices, conservation, restoration. INTRODUCTION .... germination for the last season was completed and seed dispersal ...... heterogeneity which is common for desert seed banks.
18. Leaking Methane from Natural Gas Vehicles: Implications for US Greenhouse Gas Reductions from the Automobile Sector
OpenAIRE
Victor, D.G.
1989-01-01
A model of the US automobile market is used to test the role that natural gas vehicles (NGVs) might play in reducing greenhouse gas emissions. Since natural gas (methane) emits less CO2 per unit of energy than petroleum products, NGVs are an obvious pathway to lower CO2 emissions. High and low demand scenarios are used to forecast the emissions from unrestricted growth and a modest program of conservation, respectively. Based on these scenarios, a reference scenario is developed that projects...
19. Behavioural models of population growth rates: implications for conservation and prediction.
OpenAIRE
Sutherland, William J.; Norris, Ken
2002-01-01
Conservation biologists often wish to predict how vertebrate populations will respond to local or global changes in conditions such as those resulting from sea-level rise, deforestation, exploitation, genetically modified crops, global warming, human disturbance or from conservation activities. Predicting the consequences of such changes almost always requires understanding the population growth rate and the density dependence. Traditional means of directly measuring density dependence are of...
20. Tendril perversion-a physical implication of the topological conservation law
Energy Technology Data Exchange (ETDEWEB)
Pieranski, Piotr [Laboratory of Computational Physics and Semiconductors, Poznan University of Technology, Nieszawska 13A, 60 965 Poznan (Poland); Baranska, Justyna [Laboratory of Computational Physics and Semiconductors, Poznan University of Technology, Nieszawska 13A, 60 965 Poznan (Poland); Skjeltorp, Arne [Institute for Energy Technology, Kjeller (Norway)
2004-09-10
Tendril perversion-a phenomenon ruled by the topological conservation law-is presented. A contemporary, quantitative analysis of the phenomenon is confronted with its qualitative, intuitive analysis carried out by Charles Darwin. The linking number, twist and writhe are defined. The topological conservation law is introduced. The Gauss formula for calculating the linking number and the Calugareanu formula for calculating writhe are derived and discussed using physical arguments.
1. Classifying Residents who use Landscape Irrigation: Implications for Encouraging Water Conservation Behavior
Science.gov (United States)
Warner, Laura A.; Lamm, Alexa J.; Rumble, Joy N.; Martin, Emmett T.; Cantrell, Randall
2016-08-01
Large amounts of water applied as urban irrigation can often be reduced substantially without compromising esthetics. Thus, encouraging the adoption of water-saving technologies and practices is critical to preserving water resources, yet difficult to achieve. The research problem addressed in this study is the lack of characterization of residents who use urban irrigation, which hinders the design of effective behavior change programs. This study examined audience segmentation as an approach to encouraging change using current residential landscape practices. K-means cluster analysis identified three meaningful subgroups among residential landscape irrigation users ( N = 1,063): the water considerate majority ( n = 479, 45 %), water savvy conservationists ( n = 378, 36 %), and unconcerned water users ( n = 201, 19 %). An important finding was that normative beliefs, attitudes, and perceived behavioral control characteristics of the subgroups were significantly different with large and medium practical effect sizes. Future water conservation behaviors and perceived importance of water resources were also significantly different among subgroups. The water considerate majority demonstrated capacity to conserve, placed high value on water, and were likely to engage in behavior changes. This article contributes to the literature on individuals who use residential landscape irrigation, an important target audience with potential to conserve water through sustainable irrigation practices and technologies. Findings confirm applicability of the capacity to conserve water to audience segmentation and extend this concept by incorporating perceived value of water resources and likelihood of conservation. The results suggest practical application to promoting residential landscape water conservation behaviors based on important audience characteristics.
2. Conservation of the Eastern Taiwan Strait Chinese White Dolphin (Sousa chinensis): Fishers' Perspectives and Management Implications
Science.gov (United States)
Liu, Ta-Kang; Wang, Yu-Cheng; Chuang, Laurence Zsu-Hsin; Chen, Chih-How
2016-01-01
The abundance of the eastern Taiwan Strait (ETS) population of the Chinese white dolphin (Sousa chinensis) has been estimated to be less than 100 individuals. It is categorized as critically endangered in the IUCN Red List of Threatened Species. Thus, immediate measures of conservation should be taken to protect it from extinction. Currently, the Taiwanese government plans to designate its habitat as a Major Wildlife Habitat (MWH), a type of marine protected area (MPA) for conservation of wildlife species. Although the designation allows continuing the current exploitation, however, it may cause conflicts among multiple stakeholders with competing interests. The study is to explore the attitude and opinions among the stakeholders in order to better manage the MPA. This study employs a semi-structured interview and a questionnaire survey of local fishers. Results from interviews indicated that the subsistence of fishers remains a major problem. It was found that stakeholders have different perceptions of the fishers’ attitude towards conservation and also thought that the fishery-related law enforcement could be difficult. Quantitative survey showed that fishers are generally positive towards the conservation of the Chinese white dolphin but are less willing to participate in the planning process. Most fishers considered temporary fishing closure as feasible for conservation. The results of this study provide recommendations for future efforts towards the goal of better conservation for this endangered species. PMID:27526102
3. Conservation of the Eastern Taiwan Strait Chinese White Dolphin (Sousa chinensis): Fishers' Perspectives and Management Implications.
Science.gov (United States)
Liu, Ta-Kang; Wang, Yu-Cheng; Chuang, Laurence Zsu-Hsin; Chen, Chih-How
2016-01-01
The abundance of the eastern Taiwan Strait (ETS) population of the Chinese white dolphin (Sousa chinensis) has been estimated to be less than 100 individuals. It is categorized as critically endangered in the IUCN Red List of Threatened Species. Thus, immediate measures of conservation should be taken to protect it from extinction. Currently, the Taiwanese government plans to designate its habitat as a Major Wildlife Habitat (MWH), a type of marine protected area (MPA) for conservation of wildlife species. Although the designation allows continuing the current exploitation, however, it may cause conflicts among multiple stakeholders with competing interests. The study is to explore the attitude and opinions among the stakeholders in order to better manage the MPA. This study employs a semi-structured interview and a questionnaire survey of local fishers. Results from interviews indicated that the subsistence of fishers remains a major problem. It was found that stakeholders have different perceptions of the fishers' attitude towards conservation and also thought that the fishery-related law enforcement could be difficult. Quantitative survey showed that fishers are generally positive towards the conservation of the Chinese white dolphin but are less willing to participate in the planning process. Most fishers considered temporary fishing closure as feasible for conservation. The results of this study provide recommendations for future efforts towards the goal of better conservation for this endangered species.
4. Reconciling nature conservation and traditional farming practices: a spatially explicit framework to assess the extent of High Nature Value farmlands in the European countryside.
Science.gov (United States)
Lomba, Angela; Alves, Paulo; Jongman, Rob H G; McCracken, David I
2015-03-01
Agriculture constitutes a dominant land cover worldwide, and rural landscapes under extensive farming practices acknowledged due to high biodiversity levels. The High Nature Value farmland (HNVf) concept has been highlighted in the EU environmental and rural policies due to their inherent potential to help characterize and direct financial support to European landscapes where high nature and/or conservation value is dependent on the continuation of specific low-intensity farming systems. Assessing the extent of HNV farmland by necessity relies on the availability of both ecological and farming systems' data, and difficulties associated with making such assessments have been widely described across Europe. A spatially explicit framework of data collection, building out from local administrative units, has recently been suggested as a means of addressing such difficulties. This manuscript tests the relevance of the proposed approach, describes the spatially explicit framework in a case study area in northern Portugal, and discusses the potential of the approach to help better inform the implementation of conservation and rural development policies. Synthesis and applications: The potential of a novel approach (combining land use/cover, farming and environmental data) to provide more accurate and efficient mapping and monitoring of HNV farmlands is tested at the local level in northern Portugal. The approach is considered to constitute a step forward toward a more precise targeting of landscapes for agri-environment schemes, as it allowed a more accurate discrimination of areas within the case study landscape that have a higher value for nature conservation.
5. Understanding natural moisturizing mechanisms: implications for moisturizer technology.
Science.gov (United States)
Chandar, Prem; Nole, Greg; Johnson, Anthony W
2009-07-01
Dry skin and moisturization are important topics because they impact the lives of many individuals. For most individuals, dry skin is not a notable concern and can be adequately managed with current moisturizing products. However, dry skin can affect the quality of life of some individuals because of the challenges of either harsh environmental conditions or impaired stratum corneum (SC) dry skin protection processes resulting from various common skin diseases. Dry skin protection processes of the SC, such as the development of natural moisturizing factor (NMF), are complex, carefully balanced, and easily perturbed. We discuss the importance of the filaggrin-NMF system and the composition of NMF in both healthy and dry skin, and also reveal new insights that suggest the properties required for a new generation of moisturizing technologies.
6. Implications of the Reduction Principal for Cosmological Natural Selection
CERN Document Server
Altenberg, Lee
2013-01-01
Smolin (1992) proposed a Darwinian process of universe reproduction - Cosmological Natural Selection - to account for the values of the parameters of the Standard Model. This idea can also be brought to bear on the laws of inheritance proposed to operate during universe production. Universe inheritance laws can themselves evolve within an enlarged state space of universe properties (another recent proposal of Smolin) that includes variation in the transmission laws. This is the strategy introduced by Nei (1967) to understand genetic transmission, through the evolutionary theory of modifier genes, whose methods are adopted here. When mechanisms of variation themselves vary, they are subject to Feldman's (1972) evolutionary Reduction Principle that selection favors greater faithfulness of replication. This dynamic is illustrated with a multitype branching process model of universe creation containing competing inheritance laws. The most faithful inheritance law dominates the ensemble of universes. The Reduction...
7. Arbuscular mycorrhizal fungi in national parks, nature reserves and protected areas worldwide: a strategic perspective for their in situ conservation.
Science.gov (United States)
Turrini, Alessandra; Giovannetti, Manuela
2012-02-01
Soil fungi play a crucial role in producing fundamental ecosystem services such as soil fertility, formation and maintenance, nutrient cycling and plant community dynamics. However, they have received little attention in the field of conservation biology. Arbuscular mycorrhizal fungi (AMF) are beneficial soil symbionts fulfilling a key function in the complex networks of belowground/aboveground biotic interactions as they live in association with the roots of most (80%) land plant families and influence not only soil fertility but also plant nutrition, diversity and productivity. The diversity of AMF communities can decline due to habitat loss and anthropogenic disturbance, especially in agro-ecosystems, and many valuable ecotypes could become extinct before they are even discovered. Consequently, long-term strategies are urgently needed to ensure their conservation in habitats where they naturally occur and have evolved. Protected areas, where living organisms are under the care of national and international authorities, represent an appropriate place for the in situ conservation of AMF, providing them with adapted situations together with established complex networks of interactions with different components within each specific ecosystem. Here, we review data available about the main present-day threats to AMF and the current state of knowledge about their occurrence in protected sites worldwide, providing a checklist of national parks and nature reserves where they have been reported. The aim was to offer a strategic perspective to increase awareness of the importance of conserving these beneficial plant symbionts and of preserving their biodiversity in the years to come.
8. Resilience design: toward a synthesis of cognition, learning, and collaboration for adaptive problem solving in conservation and natural resource stewardship
Directory of Open Access Journals (Sweden)
Charles G. Curtin
2014-06-01
Full Text Available Through the resilience design approach, I propose to extend the resilience paradigm by re-examining the components of adaptive decision-making and governance processes. The approach can be divided into three core components: (1 equity design, i.e., the integration of collaborative approaches to conservation and adaptive governance that generates effective self-organization and emergence in conservation and natural resource stewardship; (2 process design, i.e., the generation of more effective knowledge through strategic development of information inputs; and (3 outcome design, i.e., the pragmatic synthesis of the previous two approaches, generating a framework for developing durable and dynamic conservation and stewardship. The design of processes that incorporate perception and learning is critical to generating durable solutions, especially in developing linkages between wicked social and ecological challenges. Starting from first principles based on human cognition, learning, and collaboration, coupled with nearly two decades of practical experience designing and implementing ecosystem-level conservation and restoration programs, I present how design-based approaches to conservation and stewardship can be achieved. This context is critical in helping practitioners and resources managers undertake more effective policy and practice.
9. Conservation practice establishment in two northeast Iowa watersheds: Strategies, water quality implications, and lessons learned
Science.gov (United States)
Gassman, P.W.; Tisl, J.A.; Palas, E.A.; Fields, C.L.; Isenhart, T.M.; Schilling, K.E.; Wolter, C.F.; Seigley, L.S.; Helmers, M.J.
2010-01-01
Coldwater trout streams are important natural resources in northeast Iowa. Extensive efforts have been made by state and federal agencies to protect and improve water quality in northeast Iowa streams that include Sny Magill Creek and Bloody Run Creek, which are located in Clayton County. A series of three water quality projects were implemented in Sny Magill Creek watershed during 1988 to 1999, which were supported by multiple agencies and focused on best management practice (BMP) adoption. Water quality monitoring was performed during 1992 to 2001 to assess the impact of these installed BMPs in the Sny Magill Creek watershed using a paired watershed approach, where the Bloody Run Creek watershed served as the control. Conservation practice adoption still occurred in the Bloody Run Creek watershed during the 10-year monitoring project and accelerated after the project ended, when a multiagency supported water quality project was implemented during 2002 to 2007. Statistical analysis of the paired watershed results using a pre/post model indicated that discharge increased 8% in Sny Magill Creek watershed relative to the Bloody Run Creek watershed, turbidity declined 41%, total suspended sediment declined 7%, and NOx-N (nitrate-nitrogen plus nitrite-nitrogen) increased 15%. Similar results were obtained with a gradual change statistical model.The weak sediment reductions and increased NOx-N levels were both unexpected and indicate that dynamics between adopted BMPs and stream systems need to be better understood. Fish surveys indicate that conditions for supporting trout fisheries have improved in both streams. Important lessons to be taken from the overall study include (1) committed project coordinators, agency collaborators, and landowners/producers are all needed for successful water quality projects; (2) smaller watershed areas should be used in paired studies; (3) reductions in stream discharge may be required in these systems in order for significant sediment
10. Combining natural history collections with fisher knowledge for community-based conservation in Fiji.
Directory of Open Access Journals (Sweden)
Abigail S Golden
Full Text Available Harnessing the traditional ecological knowledge (TEK of local communities has the potential to enhance conservation planning in developing regions. Marine protected areas (MPAs that incorporate traditional beliefs about reef tenure are generally more successful in reaching conservation goals and ensuring the participation of local fishermen on vulnerable tropical reef systems. Fiji possesses a unique system of traditional reef management in which local clans or villages, called mataqali, control individual units of a reef, known as qoliqoli, and make independent management decisions based on traditional beliefs and conservation concerns. This is an example of a system, known as customary marine tenure, which has attracted interest from conservation scientists hoping to set up MPAs in vulnerable regions. As one example of this grassroots participation, Nagigi village on the Fijian island of Vanua Levu has expressed interest in setting up an MPA in part of its qoliqoli because of concerns about overfishing. In response to this interest, we took a two-pronged approach to assessing Nagigi's fishery status and conservation needs, first conducting a fishery-independent species survey using destructive sampling and then focusing on fisheries targets identified through fisher interviews. These interviews allowed us to identify heavily targeted species, assess villagers' understanding of reef dynamics over 30 or 40 years of fisheries expansion, and evaluate village support and expectations for a proposed conservation program. Based on our findings we recommend a temporary closure to be in effect for at least three years, allowing one of the more important fishery targets, Lethrinus harak (Forsskål, 1775; Lethrinidae, to complete at least one generation within the reserve. The methodology of matching the proposed marine protected area with the life histories and ecologies of heavily targeted species identified through fisherman and -woman interviews can
11. CONSIDERATIONS CONCERNING THE CONSERVATION STATUS OF THE NATURAL HABITATS FROM BUILA-VÂNTURARIŢA NATIONAL PARK
Directory of Open Access Journals (Sweden)
Monica Neblea
2013-07-01
Full Text Available In this paper a characterization of the conservation status of natural habitats from Buila-Vânturariţa National Park was maded. There were analyzed three types of habitats, according to NATURA 2000 classification, as follows: 8210 Calcareous rocky slopes with chasmophytic vegetation; 4070* Bushes with Pinus mugo and Rhododendron hirsutum (Rhododendretum hirsuti and 6190 Rupicolous Pannonic grasslands (Stipo-Festucetalia pallentis.
12. Ascertaining the nature and timing of mire degradation: using palaeoecology to assist future conservation management in Northern England
Directory of Open Access Journals (Sweden)
Frank Chambers
2017-02-01
Full Text Available Large areas of upland mire and moorland in Northwest Europe are regarded as degraded, not actively peat-forming, and releasing carbon. Conservation agencies have short-term targets to restore such areas, but often have no clear knowledge of the timing and nature of degradation. It has been suggested that palaeoecology can be used to inform conservation management about past vegetation states, so as to help identify feasible restoration targets. Our research study in northern England, commissioned by the national statutory conservation agency, applied multiple palaeoecological techniques to establish the vegetation history of several mire and moorland sites, specifically to ascertain the nature and timing of degradation. Techniques applied included pollen analysis, plant macrofossil and charcoal analyses, determination of peat humification and mineral magnetic susceptibility, with ages ascertained using spheroidal carbonaceous particle analysis, 210Pb and 14C dating. Data are presented from case-study sites in the North York Moors, North- and South Pennines to illustrate how palaeoecology can extend long-term monitoring and guide conservation management. Palaeoecological data from a site within a National Nature Reserve, subject to exceptionally long-term (half-centennial ecological monitoring, showed that this period does not include its pre-degradation state and that its current valued vegetation is novel and may have established after major fire. Overall, the studies suggest that the principal vegetation change at the sites took place after the start of the Industrial Revolution, and that the current landscape appearance not only has no long history, but that valued aspects, such as extensive heather moorland, feature only recently in the cultural landscape. These findings pose challenging questions for conservation management. We offer a non-specialist guide to the palaeoecological techniques that considers level of skill, cost, and
13. Faulting of natural serpentinite: Implications for intermediate-depth seismicity
Science.gov (United States)
Gasc, Julien; Hilairet, Nadège; Yu, Tony; Ferrand, Thomas; Schubnel, Alexandre; Wang, Yanbin
2017-09-01
The seismic potential of serpentinites at high pressure was investigated via deformation experiments on cored natural serpentinite samples, during which micro-seismicity was monitored by recording Acoustic Emissions (AEs). Deformation was performed at pressures of 3-5 GPa, using a Deformation-DIA device, and over a wide range of temperatures, both within and outside antigorite's stability field. Below 400 °C, serpentinite deformation involves ;silent; semi-brittle mechanisms, even in cases where strain localization is observed. At high temperature (i.e., above 600 °C), despite conditions propitious to dehydration embrittlement (i.e., fast strain rates and reaction kinetics), joint deformation and dehydration lead to ductile shear, without generation of AEs. Brittle behavior was observed in a narrow temperature window ca. 500 °C. In this latter case, AEs are consistently observed upon faulting and extremely sharp strain localization is observed in recovered samples. The resulting microstructures are consistent with the inverse ductile-to-brittle transition proposed by Proctor and Hirth (2016) in antigorite. This may therefore be a source of seismicity in subducting slabs at mantle pressures and temperatures from 500 to 600 °C. However, the acoustic signal observed here is orders of magnitude weaker than what is obtained at low PT conditions with brittle failure, consistently with low radiation efficiency of serpentinite faulting (Prieto et al., 2013) and suggests that other mechanisms are responsible for large intermediate-depth earthquakes. In fact, the present results are in line with a recent study (Ferrand et al., 2017), that suggests that intermediate earthquakes are likely induced by mechanical instabilities due to dehydration in partly hydrated peridotites.
14. Faulting of natural serpentinite: Implications for intermediate-depth seismicity
Energy Technology Data Exchange (ETDEWEB)
Gasc, Julien; Hilairet, Nadège; Yu, Tony; Ferrand, Thomas; Schubnel, Alexandre; Wang, Yanbin
2017-09-01
The seismic potential of serpentinites at high pressure was investigated via deformation experiments on cored natural serpentinite samples, during which micro-seismicity was monitored by recording Acoustic Emissions (AEs). Deformation was performed at pressures of 3–5 GPa, using a Deformation-DIA device, and over a wide range of temperatures, both within and outside antigorite's stability field. Below 400 °C, serpentinite deformation involves “silent” semi-brittle mechanisms, even in cases where strain localization is observed. At high temperature (i.e., above 600 °C), despite conditions propitious to dehydration embrittlement (i.e., fast strain rates and reaction kinetics), joint deformation and dehydration lead to ductile shear, without generation of AEs. Brittle behavior was observed in a narrow temperature window ca. 500 °C. In this latter case, AEs are consistently observed upon faulting and extremely sharp strain localization is observed in recovered samples. The resulting microstructures are consistent with the inverse ductile-to-brittle transition proposed by Proctor and Hirth (2016) in antigorite. This may therefore be a source of seismicity in subducting slabs at mantle pressures and temperatures from 500 to 600 °C. However, the acoustic signal observed here is orders of magnitude weaker than what is obtained at low PT conditions with brittle failure, consistently with low radiation efficiency of serpentinite faulting (Prieto et al., 2013) and suggests that other mechanisms are responsible for large intermediate-depth earthquakes. In fact, the present results are in line with a recent study (Ferrand et al., 2017), that suggests that intermediate earthquakes are likely induced by mechanical instabilities due to dehydration in partly hydrated peridotites.
15. Effect of Natural Polyphenols on CYP Metabolism: Implications for Diseases.
Science.gov (United States)
Korobkova, Ekaterina A
2015-07-20
Cytochromes P450 (CYPs) are a large group of hemeproteins located on mitochondrial membranes or the endoplasmic reticulum. They play a crucial role in the metabolism of endogenous and exogenous molecules. The activity of CYP is associated with a number of factors including redox potential, protein conformation, the accessibility of the active site by substrates, and others. This activity may be potentially modulated by a variety of small molecules. Extensive experimental data collected over the past decade point at the active role of natural polyphenols in modulating the catalytic activity of CYP. Polyphenols are widespread micronutrients present in human diets of plant origin and in medicinal herbs. These compounds may alter the activity of CYP either via direct interactions with the enzymes or by affecting CYP gene expression. The polyphenol-CYP interactions may significantly alter the pharmacokinetics of drugs and thus influence the effectiveness of chemical therapies used in the treatment of different types of cancers, diabetes, obesity, and cardiovascular diseases (CVD). CYPs are involved in the oxidation and activation of external carcinogenic agents, in which case the inhibition of the CYP activity is beneficial for health. CYPs also support detoxification processes. In this case, it is the upregulation of CYP genes that would be favorable for the organism. A CYP enzyme aromatase catalyzes the formation of estrone and estradiol from their precursors. CYPs also catalyze multiple reactions leading to the oxidation of estrogen. Estrogen signaling and oxidative metabolism of estrogen are associated with the development of cancer. Thus, polyphenol-mediated modulation of the CYP's activity also plays a vital role in estrogen carcinogenesis. The aim of the present review is to summarize the data collected over the last five to six years on the following topics: (1) the mechanisms of the interactions of CYP with food constituents that occur via the direct binding of
16. Conservation implications of deforestation across an elevational gradient in the Eastern Arc Mountains, Tanzania
DEFF Research Database (Denmark)
Hall, Jaclyn; Burgess, Neil David; Lovett, Jon
2009-01-01
Deforestation is a major threat to the conservation of biodiversity, especially within global centers of endemism for plants and animals. Elevation, the major environmental gradient in mountain regions of the world, produces a rapid turnover of species, where some species may exist only in narrow...... habitat in their elevational range. When elevational range is considered, 98 (80%) of these endemic forest trees should have their level of extinction threat elevated on the IUCN Red List. Conservation efforts in montane hotspots need to consider the extent of habitat changes both within and across...
17. Geometrid moth assemblages reflect high conservation value of naturally regenerated secondary forests in temperate China
NARCIS (Netherlands)
Zou, Yi; Sang, Weiguo; Warren-Thomas, Eleanor; Axmacher, Jan Christoph
2016-01-01
The widespread destruction of mature forests in China has led to massive ecological degradation, counteracted in recent decades by substantial efforts to promote forest plantations and protect secondary forest ecosystems. The value of the resulting forests for biodiversity conservation is widely
18. Natural gas at thermodynamic equilibrium. Implications for the origin of natural gas.
Science.gov (United States)
Mango, Frank D; Jarvie, Daniel; Herriman, Eleanor
2009-06-16
It is broadly accepted that so-called 'thermal' gas is the product of thermal cracking, 'primary' thermal gas from kerogen cracking, and 'secondary' thermal gas from oil cracking. Since thermal cracking of hydrocarbons does not generate products at equilibrium and thermal stress should not bring them to equilibrium over geologic time, we would not expect methane, ethane, and propane to be at equilibrium in subsurface deposits. Here we report compelling evidence of natural gas at thermodynamic equilibrium. Molecular compositions are constrained to equilibrium, [Formula in text] and isotopic compositions are also under equilibrium constraints: [Formula in text].The functions [(CH4)*(C3H8)] and [(C2H6)2] exhibit a strong nonlinear correlation (R2 = 0.84) in which the quotient Q progresses to K as wet gas progresses to dry gas. There are striking similarities between natural gas and catalytic gas generated from marine shales. A Devonian/Mississippian New Albany shale generates gas with Q converging on K over time as wet gas progresses to dry gas at 200 degrees C. The position that thermal cracking is the primary source of natural gas is no longer tenable. It is challenged by its inability to explain the composition of natural gas, natural gases at thermodynamic equilibrium, and by the existence of a catalytic path to gas that better explains gas compositions.
19. Natural gas at thermodynamic equilibrium Implications for the origin of natural gas
Directory of Open Access Journals (Sweden)
Jarvie Daniel
2009-06-01
Full Text Available Abstract It is broadly accepted that so-called 'thermal' gas is the product of thermal cracking, 'primary' thermal gas from kerogen cracking, and 'secondary' thermal gas from oil cracking. Since thermal cracking of hydrocarbons does not generate products at equilibrium and thermal stress should not bring them to equilibrium over geologic time, we would not expect methane, ethane, and propane to be at equilibrium in subsurface deposits. Here we report compelling evidence of natural gas at thermodynamic equilibrium. Molecular compositions are constrained to equilibrium, and isotopic compositions are also under equilibrium constraints: The functions [(CH4*(C3H8] and [(C2H62] exhibit a strong nonlinear correlation (R2 = 0.84 in which the quotient Q progresses to K as wet gas progresses to dry gas. There are striking similarities between natural gas and catalytic gas generated from marine shales. A Devonian/Mississippian New Albany shale generates gas with Q converging on K over time as wet gas progresses to dry gas at 200°C. The position that thermal cracking is the primary source of natural gas is no longer tenable. It is challenged by its inability to explain the composition of natural gas, natural gases at thermodynamic equilibrium, and by the existence of a catalytic path to gas that better explains gas compositions.
20. A Framework for Evaluating Forest Conservation Implications of Community-based Capacity Building: Experiences from the Northern Bolivian Amazon
Directory of Open Access Journals (Sweden)
Kelly Biedenweg
2012-01-01
Full Text Available Capacity-building projects in forest-based communities are implemented by governments, cooperatives, and non-government organisations to encourage sustainable management of community forests. While such projects are regularly evaluated on a case-by-case basis, they are rarely subjected to a landscape-level examination to explore conservation implications. To understand how environmental capacity-building projects address regional conservation goals, an interdisciplinary framework was developed to highlight the thematic focus, the geographic distribution, and the degree of community participation in environmental capacity-building projects. We demonstrate how the framework can be used by characterising projects in campesino communities in the Amazonian department of Pando, Bolivia, that were active during 2006-2008. While projects were too recent to affect forest cover, we describe how the framework elucidates three project themes (timber, Brazil nut, and agroforestry management; that project distribution was largely related to land tenure security, proximity to town, historical relationships, and motorised access; and that capacity-building strategies varied in participation, depending on thematic content and federal requirements for specific resources. We then discuss how the framework can be used to analyse forest cover implications over many years. Understanding the combination of thematic focus, geographic distribution, and degree of participation in project strategies offers a foundation for understanding how capacity-building initiatives can influence forest landscapes.
1. Nature on the Move: The Value and Circulation of Liquid Nature and the Emergence of Fictitious Conservation
NARCIS (Netherlands)
B.E. Büscher (Bram)
2013-01-01
markdownabstract__Abstract__ A rich body of literature investigates the many ways in which nature is impacted upon and transformed by the “endless accumulation of capital.” Much less attention has been reserved for understanding how capitalist actors increasingly aim to profit from the non-extracti
2. Temporal correlations in population trends: Conservation implications from time-series analysis of diverse animal taxa
Science.gov (United States)
David Keith; H. Resit Akcakaya; Stuart H.M. Butchart; Ben Collen; Nicholas K. Dulvy; Elizabeth E. Holmes; Jeffrey A. Hutchings; Doug Keinath; Michael K. Schwartz; Andrew O. Shelton; Robin S. Waples
2015-01-01
Population trends play a large role in species risk assessments and conservation planning, and species are often considered threatened if their recent rate of decline meets certain thresholds, regardless how large the population is. But how reliable an indicator of extinction risk is a single estimate of population trend? Given the integral role this decline-...
3. Exploring Children's Perceptions of Cheetahs through Storytelling: Implications for Cheetah Conservation
Science.gov (United States)
Hughes, Courtney
2013-01-01
Namibia's cheetah population has predominantly been threatened by human conflict related to livestock farming and habitat loss. Cheetahs have been indiscriminately persecuted as a mortal threat to livestock, as well as suffered from human-caused land use change. The Cheetah Conservation Fund (CCF) in Otjiwarongo, Namibia conducts cheetah research…
4. Genetic diversity and population structure of locally adapted South African chicken lines: Implications for conservation.
NARCIS (Netherlands)
Marle-Koster, van E.; Hefer, C.A.; Nel, L.H.; Groenen, M.A.M.
2008-01-01
In this study microsatellite markers were applied to investigate the genetic diversity and population structure of the six local chicken lines kept in the “Fowls for Africa” program, for better clarification of parameters for breed differentiation and genetic conservation of this valuable resource.
5. Half-Earth or Whole Earth? Radical ideas for conservation, and their implications
NARCIS (Netherlands)
Büscher, Bram; Fletcher, Robert; Brockington, Dan; Sandbrook, Chris; Adams, William M.; Campbell, Lisa; Corson, Catherine; Dressler, Wolfram; Duffy, Rosaleen; Gray, Noella; Holmes, George; Kelly, Alice; Lunstrum, Elizabeth; Ramutsindela, Maano; Shanker, Kartik
2017-01-01
We question whether the increasingly popular, radical idea of turning half the Earth into a network of protected areas is either feasible or just. We argue that this Half-Earth plan would have widespread negative consequences for human populations and would not meet its conservation objectives. It
6. Participatory mapping to identify indigenous community use zones : Implications for conservation planning in southern Suriname
NARCIS (Netherlands)
Ramirez-Gomez, Sara O I; Brown, Greg; Verweij, Pita A.; Boot, René
2016-01-01
Large-scale development projects often overlap forest areas that support the livelihoods of indigenous peoples, threatening in situ conservation strategies for the protection of biological and cultural diversity. To address this problem, there is a need to integrate spatially-explicit information on
7. Conservation tillage systems and water productivity implications for smallholder farmers in semi-arid Ethiopia
NARCIS (Netherlands)
Temesgen, M.L.
2007-01-01
Conservation tillage systems have been adopted by farmers in many countries to solve the problem of land degradation and declining water productivity. However, direct application of such tillage systems was not possible among resource poor smallholder farmers in semi arid areas of Ethiopia. Problems
8. Riverscape patterns among years of juvenile coho salmon in midcoastal Oregon: implications for conservation
Science.gov (United States)
R. Flitcroft; K. Burnett; J. Snyder; G. Reeves; L. Ganio
2014-01-01
Patterns of salmon distribution throughout a riverscape may be expected to change over time in response to environmental conditions and population sizes. Changing patterns of use, including identification of consistently occupied locations, are informative for conservation and recovery planning. We explored interannual patterns of distribution by juvenile Coho Salmon...
9. Examining the extinction of the Barbary lion and its implications for felid conservation.
Directory of Open Access Journals (Sweden)
Simon A Black
Full Text Available Estimations of species extinction dates are rarely definitive, yet declarations of extinction or extirpation are important as they define when conservation efforts may cease. Erroneous declarations of extinctions not only destabilize conservation efforts but also corrode local community support. Mismatches in perceptions by the scientific and local communities risk undermining sensitive, but important partnerships. We examine observations relating to the decline and extinction of Barbary lions in North Africa. Whilst the extinction predates the era of the scientific conservation movement, the decline is relatively well documented in historical records. Recently unearthed accounts suggest Barbary lions survived later than previously assumed. We use probabilistic methods to estimate a more recent extinction date for the subspecies. The evidence presented for a much later persistence of lions in North Africa, including generations when sightings were nil, suggests caution when considering felid populations as extinct in the wild. The case raises the possibility that captive animals descended from the Moroccan royal collection are closer contemporaries to wild Barbary lions. Furthermore, our results highlight the vulnerability of very small lion populations and the significance of continued conservation of remnant lion populations in Central and West Africa.
10. Farmer Perceptions of Soil and Water Conservation Issues: Implications to Agricultural and Extension Education.
Science.gov (United States)
Bruening, Thomas; Martin, Robert A.
1992-01-01
A survey of 731 Iowa farmers received 432 responses indicating that (1) groundwater and water quality were of greater concern than soil conservation; (2) field demonstrations and county meetings were useful information sources on these issues; and (3) government agencies such as cooperative extension and state universities were useful sources of…
11. Exploring Children's Perceptions of Cheetahs through Storytelling: Implications for Cheetah Conservation
Science.gov (United States)
Hughes, Courtney
2013-01-01
Namibia's cheetah population has predominantly been threatened by human conflict related to livestock farming and habitat loss. Cheetahs have been indiscriminately persecuted as a mortal threat to livestock, as well as suffered from human-caused land use change. The Cheetah Conservation Fund (CCF) in Otjiwarongo, Namibia conducts cheetah research…
12. Multiple Knowledges for Agricultural Production: Implications for the Development of Conservation Agriculture in Kenya and Uganda
Science.gov (United States)
Moore, Keith M.; Lamb, Jennifer N.; Sikuku, Dominic Ngosia; Ashilenje, Dennis S.; Laker-Ojok, Rita; Norton, Jay
2014-01-01
Purpose: This article investigates the extent of multiple knowledges among smallholders and connected non-farm agents around Mount Elgon in Kenya and Uganda in order to build the communicative competence needed to scale up conservation agriculture production systems (CAPS). Design/methodology/approach: Our methodological approach examines local…
13. Revisiting Nature vs. Nurture: Implications for the Teaching/Learning Process.
Science.gov (United States)
French, Fred
2003-01-01
Child development theories conclude that nature and nurture interactively shape individual development. Implications for education are that children learn better when they feel wanted and are in a supportive environment. Teaching needs to go beyond pure content and focus on learning how to learn. Assessment should focus on the use of knowledge…
14. Revisiting Nature vs. Nurture: Implications for the Teaching/Learning Process.
Science.gov (United States)
French, Fred
2003-01-01
Child development theories conclude that nature and nurture interactively shape individual development. Implications for education are that children learn better when they feel wanted and are in a supportive environment. Teaching needs to go beyond pure content and focus on learning how to learn. Assessment should focus on the use of knowledge…
15. The Contingent Constructed Nature of Social Life: Suggested Implications for Library and Information Science.
Science.gov (United States)
Hall, Peter M.
1990-01-01
Discusses a variety of topics and their implications for library and information science professionals and their education. Highlights include the nature of science; contingency theories; the assumptions of sociology; the approach of symbolic interaction; recent scholarship on organizations; and the advantages of qualitative research methods.…
16. Picking up the pieces: conserving remnant natural areas in the post-industrial landscape of the Calumet Region
Science.gov (United States)
Labus, Paul; Whitman, Richard L.; Nevers, Meredith Becker
1999-01-01
The Calumet Region was shaped by geologic forces, succession, and interacting biomes converging on a unique natural landscape. Over the past 4500 years, a strand plain has formed to the north of a geologic area called Toleston Beach. Sequential and differential primary succession of dune and swale communities in this region allowed species from different biomes to interact freely. In the mid-nineteenth century, commerce and settlement drastically changed the area, and natural areas were fragmented, manipulated, and degraded by cultural intrusions and industrialization. Despite the near obliteration of dune and swale habitat, small fragments of natural land escaped destruction. These native fragments maintained some semblance of the landscape that once covered the region. Currently, these native fragments are threatened by the lingering intrusion of historic contamination and the continuing presence of industry and commerce. Restoration and conservation of these remnants will need to be a process of integrating biological diversity goals into the landscape of the industrialized region through planning and design. We outline here the natural history of the region, the philosophical rationale for conservation, and possible approaches for integrating and maintaining these valuable remnant resources and processes.
17. State-Led Ecotourism Development and Nature Conservation: a Case Study of the Changbai Mountain Biosphere Reserve, China
Directory of Open Access Journals (Sweden)
Qingli Wang
2008-12-01
Full Text Available Faced with fiscal constraints and enormous population pressures, 80% of Chinese nature reserves have employed ecotourism as a support and development strategy. Assessing the actual effects of ecotourism at a nature reserve that has a relatively long history of ecotourism development experience may be instructive for other reserves. Therefore, we take Changbai Mountain Biosphere Reserve (CMBR in northeastern China as a case study, for it is one of the pioneers in embracing ecotourism in China. Personal interviews and informal group discussions were employed to understand local residents’ attitudes toward conservation. Factors affecting their attitudes were then analyzed using logistic regression. Results indicate that attitudes held by most farmers are not favorable toward the conservation of the CMBR. It is not ecotourism but rather income from collection of forest products, household crop lands, and migrant labor that actually influences their attitudes. We found that the 1-day-sightseeing tour style, the limited tourism period, and the low level of education and extreme poverty of the local residents, together with existing institutions and lagging regulations make it very difficult for ecotourism to engender local residents’ support. We concluded that institutional measures to guarantee local people’s sharing in the revenue generated by the reserve, as well as regulations to ensure involvement of the local community in the decision-making process are preconditions for ecotourism to engender local support in China. Providing educational opportunities for children and vocational training for young local residents can also contribute indirectly to enhanced conservation.
18. Conserved natural IgM antibodies mediate innate and adaptive immunity against the opportunistic fungus Pneumocystis murina.
Science.gov (United States)
Rapaka, Rekha R; Ricks, David M; Alcorn, John F; Chen, Kong; Khader, Shabaana A; Zheng, Mingquan; Plevy, Scott; Bengtén, Eva; Kolls, Jay K
2010-12-20
Host defense against opportunistic fungi requires coordination between innate and adaptive immunity for resolution of infection. Antibodies generated in mice vaccinated with the fungus Pneumocystis prevent growth of Pneumocystis organisms within the lungs, but the mechanisms whereby antibodies enhance antifungal host defense are poorly defined. Nearly all species of fungi contain the conserved carbohydrates β-glucan and chitin within their cell walls, which may be targets of innate and adaptive immunity. In this study, we show that natural IgM antibodies targeting these fungal cell wall carbohydrates are conserved across many species, including fish and mammals. Natural antibodies bind fungal organisms and enhance host defense against Pneumocystis in early stages of infection. IgM antibodies influence recognition of fungal antigen by dendritic cells, increasing their migration to draining pulmonary lymph nodes. IgM antibodies are required for adaptive T helper type 2 (Th2) and Th17 cell differentiation and guide B cell isotype class-switch recombination during host defense against Pneumocystis. These experiments suggest a novel role for the IgM isotype in shaping the earliest steps in recognition and clearance of this fungus. We outline a mechanism whereby serum IgM, containing ancient specificities against conserved fungal antigens, bridges innate and adaptive immunity against fungal organisms.
19. Sex-specific ecophysiological responses to environmental fluctuations of free-ranging Hermann's tortoises: implication for conservation
Science.gov (United States)
Sibeaux, Adélaïde; Michel, Catherine Louise; Bonnet, Xavier; Caron, Sébastien; Fournière, Kévin; Gagno, Stephane; Ballouard, Jean-Marie
2016-01-01
Physiological parameters provide indicators to evaluate how organisms respond to conservation actions. For example, individuals translocated during reinforcement programmes may not adapt to their novel host environment and may exhibit elevated chronic levels of stress hormones and/or decreasing body condition. Conversely, successful conservation actions should be associated with a lack of detrimental physiological perturbation. However, physiological references fluctuate over time and are influenced by various factors (e.g. sex, age, reproductive status). It is therefore necessary to determine the range of natural variations of the selected physiological metrics to establish useful baselines. This study focuses on endangered free-ranging Hermann's tortoises (Testudo hermanni hermanni), where conservation actions have been preconized to prevent extinction of French mainland populations. The influence of sex and of environmental factors (site, year and season) on eight physiological parameters (e.g. body condition, corticosterone concentrations) was assessed in 82 individuals from two populations living in different habitats. Daily displacements were monitored by radio-tracking. Most parameters varied between years and seasons and exhibited contrasting sex patterns but with no or limited effect of site. By combining behavioural and physiological traits, this study provides sex-specific seasonal baselines that can be used to monitor the health status of Hermann's tortoises facing environmental threats (e.g. habitat changes) or during conservation actions (e.g. translocation). These results might also assist in selection of the appropriate season for translocation. PMID:27933166
20. Natural gas at thermodynamic equilibrium Implications for the origin of natural gas
OpenAIRE
Jarvie Daniel; Mango Frank D; Herriman Eleanor
2009-01-01
Abstract It is broadly accepted that so-called 'thermal' gas is the product of thermal cracking, 'primary' thermal gas from kerogen cracking, and 'secondary' thermal gas from oil cracking. Since thermal cracking of hydrocarbons does not generate products at equilibrium and thermal stress should not bring them to equilibrium over geologic time, we would not expect methane, ethane, and propane to be at equilibrium in subsurface deposits. Here we report compelling evidence of natural gas at ther...
1. Dugong dugon feeding in tropical Australian seagrass meadows: implications for conservation planning
Directory of Open Access Journals (Sweden)
Samantha J. Tol
2016-07-01
Full Text Available Dugongs (Dugong dugon are listed as vulnerable to extinction due to rapid population reductions caused in part by loss of seagrass feeding meadows. Understanding dugong feeding behaviour in tropical Australia, where the majority of dugongs live, will assist conservation strategies. We examined whether feeding patterns in intertidal seagrass meadows in tropical north-eastern Australia were related to seagrass biomass, species composition and/or nitrogen content. The total biomass of each seagrass species removed by feeding dugongs was measured and compared to its relative availability. Nitrogen concentrations were also determined for each seagrass species present at the sites. Dugongs consumed seagrass species in proportion to their availability, with biomass being the primary determining factor. Species composition and/or nitrogen content influenced consumption to a lesser degree. Conservation plans focused on protecting high biomass intertidal seagrass meadows are likely to be most effective at ensuring the survival of dugong in tropical north-eastern Australia.
2. Biodiversity and Habitat Markets—Policy, Economic, and Ecological implications of Market-Based Conservation
Science.gov (United States)
Pindilli, Emily; Casey, Frank
2015-10-26
This report is a primer on market-like and market-based mechanisms designed to conserve biodiversity and habitat. The types of markets and market-based approaches that were implemented or are emerging to benefit biodiversity and habitat in the United States are examined. The central approaches considered in this report include payments for ecosystem services, conservation banks, habitat exchanges, and eco-labels. Based on literature reviews and input from experts and practitioners, the report characterizes each market-based approach including policy context and structure; the theoretical basis for applying market-based approaches; the ecological effectiveness of practices and tools for measuring performance; and the future outlook for biodiversity and habitat markets. This report draws from previous research and serves as a summary of pertinent information associated with biodiversity and habitat markets while providing references to materials that go into greater detail on specific topics.
3. Inverted migration of rare whisker sheatfish in Nong-Han Lake, northeastern Thailand: implications for conservation.
Science.gov (United States)
Phongkaew, P; Arunyawat, U; Swatdipong, A; Hongtrakul, V
2014-09-12
Nong-Han Lake, Thailand, sustains the whisker sheatfish (Micronema bleekeri Günther, 1864), which is a rare species of freshwater catfish. Wild-caught whisker sheatfish has been intensively harvested to meet market demand; yet, genetic information about this species remains unknown. To assist with the in situ conservation of whisker sheatfish populations in Nong-Han Lake, 35 and 34 individuals from the middle (MN) and lower (LN) areas of the lake, respectively, were studied using 7 microsatellite loci. Low genetic variation was detected in the MN (HO=0.338, AR=2.710) and LN (HO=0.394, AR=2.714) populations. Genetic differentiation between the 2 populations was significant (FST=0.063, PChao Phraya River basins is required to assist national-scale conservation efforts.
4. Dugong dugon feeding in tropical Australian seagrass meadows: implications for conservation planning.
Science.gov (United States)
Tol, Samantha J; Coles, Rob G; Congdon, Bradley C
2016-01-01
Dugongs (Dugong dugon) are listed as vulnerable to extinction due to rapid population reductions caused in part by loss of seagrass feeding meadows. Understanding dugong feeding behaviour in tropical Australia, where the majority of dugongs live, will assist conservation strategies. We examined whether feeding patterns in intertidal seagrass meadows in tropical north-eastern Australia were related to seagrass biomass, species composition and/or nitrogen content. The total biomass of each seagrass species removed by feeding dugongs was measured and compared to its relative availability. Nitrogen concentrations were also determined for each seagrass species present at the sites. Dugongs consumed seagrass species in proportion to their availability, with biomass being the primary determining factor. Species composition and/or nitrogen content influenced consumption to a lesser degree. Conservation plans focused on protecting high biomass intertidal seagrass meadows are likely to be most effective at ensuring the survival of dugong in tropical north-eastern Australia.
5. Structural proteomics of minimal organisms: conservation ofprotein fold usage and evolutionary implications
Energy Technology Data Exchange (ETDEWEB)
Chandonia, John-Marc; Kim, Sung-Hou
2006-03-15
Background: Determining the complete repertoire of proteinstructures for all soluble, globular proteins in a single organism hasbeen one of the major goals of several structural genomics projects inrecent years. Results: We report that this goal has nearly been reachedfor several "minimal organisms"--parasites or symbionts with reducedgenomes--for which over 95 percent of the soluble, globular proteins maynow be assigned folds, overall 3-D backbone structures. We analyze thestructures of these proteins as they relate to cellular functions, andcompare conservation off old usage between functional categories. We alsocompare patterns in the conservation off olds among minimal organisms andthose observed between minimal organisms and other bacteria. Conclusion:We find that proteins performing essential cellular functions closelyrelated to transcription and translation exhibit a higher degree ofconservation in fold usage than proteins in other functional categories.Folds related to transcription and translation functional categories werealso over represented in minimal organisms compared to otherbacteria.
6. Genetic diversity and conservation implications of four Cupressus species in China as revealed by microsatellite markers.
Science.gov (United States)
Lu, Xu; Xu, Haiyan; Li, Zhonghu; Shang, Huiying; Adams, Robert P; Mao, Kangshan
2014-04-01
Understanding the extent and distribution of genetic diversity is crucial for the conservation and management of endangered species. Cupressus chengiana, C. duclouxiana, C. gigantea, and C. funebris are four ecologically and economically important species in China. We investigated their genetic diversity, population structure, and extant effective population size (35 populations, 484 individuals) employing six pairs of nuclear microsatellite markers (selected from 53). Their genetic diversity is moderate among conifers, and genetic differentiation among populations is much lower in C. gigantea than in the other three species; the estimated effective population size was largest for C. chengiana, at 1.70, 2.91, and 3.91 times the estimates for C. duclouxiana, C. funebris, and C. gigantea, respectively. According to Bayesian clustering analysis, the most plausible population subdivision scheme within species is two groups in C. chengiana, three groups in C. duclouxiana, and a single group for both C. funebris and C. gigantea. We propose a conservation strategy for these cypress species.
7. Wildlife translocation: the conservation implications of pathogen exposure and genetic heterozygosity
OpenAIRE
Penedo M Cecilia T; Weisenberger Mara E; Boyce Walter M; Johnson Christine K
2011-01-01
Abstract Background A key challenge for conservation biologists is to determine the most appropriate demographic and genetic management strategies for wildlife populations threatened by disease. We explored this topic by examining whether genetic background and previous pathogen exposure influenced survival of translocated animals when captive-bred and free-ranging bighorn sheep (Ovis canadensis) were used to re-establish a population that had been extirpated in the San Andres Mountains in Ne...
8. One-Party Dominance: Future Political Implications for the Conservatives in South Korea
Science.gov (United States)
2016-12-01
Lee’s intent was to open the market to competition, he only flooded the media market with more conservative news outlets. When the Korean government ... data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden...position of the Department of Defense or the U.S. Government . IRB number ____N/A____. 12a. DISTRIBUTION / AVAILABILITY STATEMENT Approved for public
9. Resembling a viper: implications of mimicry for conservation of the endangered smooth snake.
Science.gov (United States)
Valkonen, Janne K; Mappes, Johanna
2014-12-01
The phenomenon of Batesian mimicry, where a palatable animal gains protection against predation by resembling an unpalatable model, has been a core interest of evolutionary biologists for 150 years. An extensive range of studies has focused on revealing mechanistic aspects of mimicry (shared education and generalization of predators) and the evolutionary dynamics of mimicry systems (co-operation vs. conflict) and revealed that protective mimicry is widespread and is important for individual fitness. However, according to our knowledge, there are no case studies where mimicry theories have been applied to conservation of mimetic species. Theoretically, mimicry affects, for example, frequency dependency of predator avoidance learning and human induced mortality. We examined the case of the protected, endangered, nonvenomous smooth snake (Coronella austriaca) that mimics the nonprotected venomous adder (Vipera berus), both of which occur in the Åland archipelago, Finland. To quantify the added predation risk on smooth snakes caused by the rarity of vipers, we calculated risk estimates from experimental data. Resemblance of vipers enhances survival of smooth snakes against bird predation because many predators avoid touching venomous vipers. Mimetic resemblance is however disadvantageous against human predators, who kill venomous vipers and accidentally kill endangered, protected smooth snakes. We found that the effective population size of the adders in Åland is very low relative to its smooth snake mimic (28.93 and 41.35, respectively).Because Batesian mimicry is advantageous for the mimic only if model species exist in sufficiently high numbers, it is likely that the conservation program for smooth snakes will fail if adders continue to be destroyed. Understanding the population consequences of mimetic species may be crucial to the success of endangered species conservation. We suggest that when a Batesian mimic requires protection, conservation planners should
10. Impact of Canopy Openness on Spider Communities: Implications for Conservation Management of Formerly Coppiced Oak Forests.
Directory of Open Access Journals (Sweden)
Ondřej Košulič
Full Text Available Traditional woodland management created a mosaic of differently aged patches providing favorable conditions for a variety of arthropods. After abandonment of historical ownership patterns and traditional management and the deliberate transformation to high forest after World War II, large forest areas became darker and more homogeneous. This had significant negative consequences for biodiversity. An important question is whether even small-scale habitat structures maintained by different levels of canopy openness in abandoned coppiced forest may constitute conditions suitable for forest as well as open habitat specialists. We investigated the effect of canopy openness in former traditionally coppiced woodlands on the species richness, functional diversity, activity density, conservation value, and degree of rareness of epigeic spiders. In each of the eight studied locations, 60-m-long transect was established consisting of five pitfall traps placed at regular 15 m intervals along the gradient. Spiders were collected from May to July 2012. We recorded 90 spider species, including high proportions of xeric specialists (40% and red-listed threatened species (26%. The peaks of conservation indicators, as well as spider community abundance, were shifted toward more open canopies. On the other hand, functional diversity peaked at more closed canopies followed by a rapid decrease with increasing canopy openness. Species richness was highest in the middle of the canopy openness gradient, suggesting an ecotone effect. Ordinations revealed that species of conservation concern tended to be associated with sparse and partly opened canopy. The results show that the various components of biodiversity peaked at different levels of canopy openness. Therefore, the restoration and suitable forest management of such conditions will retain important diversification of habitats in formerly coppiced oak forest stands. We indicate that permanent presence of small
11. Impact of Canopy Openness on Spider Communities: Implications for Conservation Management of Formerly Coppiced Oak Forests
Science.gov (United States)
2016-01-01
Traditional woodland management created a mosaic of differently aged patches providing favorable conditions for a variety of arthropods. After abandonment of historical ownership patterns and traditional management and the deliberate transformation to high forest after World War II, large forest areas became darker and more homogeneous. This had significant negative consequences for biodiversity. An important question is whether even small-scale habitat structures maintained by different levels of canopy openness in abandoned coppiced forest may constitute conditions suitable for forest as well as open habitat specialists. We investigated the effect of canopy openness in former traditionally coppiced woodlands on the species richness, functional diversity, activity density, conservation value, and degree of rareness of epigeic spiders. In each of the eight studied locations, 60-m-long transect was established consisting of five pitfall traps placed at regular 15 m intervals along the gradient. Spiders were collected from May to July 2012. We recorded 90 spider species, including high proportions of xeric specialists (40%) and red-listed threatened species (26%). The peaks of conservation indicators, as well as spider community abundance, were shifted toward more open canopies. On the other hand, functional diversity peaked at more closed canopies followed by a rapid decrease with increasing canopy openness. Species richness was highest in the middle of the canopy openness gradient, suggesting an ecotone effect. Ordinations revealed that species of conservation concern tended to be associated with sparse and partly opened canopy. The results show that the various components of biodiversity peaked at different levels of canopy openness. Therefore, the restoration and suitable forest management of such conditions will retain important diversification of habitats in formerly coppiced oak forest stands. We indicate that permanent presence of small-scale improvements
12. Opportunities and challenges for private sector entrepreneurship and investment in biodiversity, ecosystem services and nature conservation
NARCIS (Netherlands)
Lambooy, T.E.; Levashova, Y.
2011-01-01
Private companies and investors can profit from the enhancement of nature in general and from specific investments allocated to improve biodiversity and ecosystem services (BES). The question is: What is the incentive, from a private sector point of view, to invest in nature, and what are the barrie
13. Opportunities and challenges for private sector entrepreneurship and investment in biodiversity, ecosystem services and nature conservation
NARCIS (Netherlands)
Lambooy, T.E.; Levashova, Y.
2011-01-01
Private companies and investors can profit from the enhancement of nature in general and from specific investments allocated to improve biodiversity and ecosystem services (BES). The question is: What is the incentive, from a private sector point of view, to invest in nature, and what are the barrie
14. Ecological Values amid Local Interests: Natural Resource Conservation, Social Differentiation, and Human Survival in Honduras
Science.gov (United States)
Gareau, Brian J.
2007-01-01
Local peoples living in protected areas often have a different understanding about their natural space than do non-local groups that promote and declare such areas "protected." By designing protected areas without local involvement, or understandings of local social differentiation and power, natural resources management schemes will likely be…
15. Which shrubs and trees can conserve natural enemies of aphids in spring?
NARCIS (Netherlands)
P.C.J. van Rijn
2014-01-01
Habitats with shrubs and trees within the agricultural landscape may contribute to the maintenance of natural enemies of pests. Aphids and flowers are important resources for beneficial natural enemies such as ladybeetles, hoverflies and lacewings. Woody plants are the most likely candidates to prov
16. Combining nature conservation and residential development in the Netherlands, England and Spain
NARCIS (Netherlands)
Elbersen, B.S.
2005-01-01
In this paper the function of protected nature in rural living environments is discussed in relation to residential choice, appreciation of the residential environment and rural development policy. In five case studies a comparison is made between the situation of protected natural areas in the Neth
17. Saproxylic Beetle Assemblage Selection as Determining Factor of Species Distributional Patterns: Implications for Conservation.
Science.gov (United States)
García-López, A; Galante, E; Micó, E
2016-01-01
The knowledge of the distributional patterns of saproxylic beetles is essential for conservation biology due to the relevance of this fauna in the maintenance of ecological processes and the endangerment of species. The complex community of saproxylic beetles is shaped by different assemblages that are composed of species linked by the microhabitats they use. We evaluate how different the species distribution patterns that are obtained can be, depending on the analyzed assemblage and to what extent these can affect conservation decisions. Beetles were sampled using hollow emergence and window traps in three protected areas of the Iberian Peninsula. Species richness, composition, and diversity turnover were analyzed for each sampling method and showed high variation depending on the analyzed assemblage. Beta diversity was clearly higher among forests for the assemblage captured using window traps. This method collects flying insects from different tree microhabitats and its captures are influenced by the forest structuring. Within forests, the assemblages captured by hollow emergence traps, which collect the fauna linked to tree hollows, showed the largest turnover of species, as they are influenced by the characteristics of each cavity. Moreover, the selection of the forest showing the highest species richness strongly depended on the studied assemblage. This study demonstrates that differences in the studied assemblages (group of species co-occurring in the same habitat) can also lead to significant differences in the identified patterns of species distribution and diversity turnover. This fact will be necessary to take into consideration when making decisions about conservation and management.
18. A trans-national monarch butterfly population model and implications for regional conservation priorities
Science.gov (United States)
Oberhauser, Karen; Wiederholt, Ruscena; Diffendorfer, James E.; Semmens, Darius J.; Ries, Leslie; Thogmartin, Wayne E.; Lopez-Hoffman, Laura; Semmens, Brice
2017-01-01
1. The monarch has undergone considerable population declines over the past decade, and the governments of Mexico, Canada, and the United States have agreed to work together to conserve the species.2. Given limited resources, understanding where to focus conservation action is key for widespread species like monarchs. To support planning for continental-scale monarch habitat restoration, we address the question of where restoration efforts are likely to have the largest impacts on monarch butterfly (Danaus plexippus Linn.) population growth rates.3. We present a spatially explicit demographic model simulating the multi-generational annual cycle of the eastern monarch population, and use the model to examine management scenarios, some of which focus on particular regions of North America.4. Improving the monarch habitat in the north central or southern parts of the monarch range yields a slightly greater increase in the population growth rate than restoration in other regions. However, combining restoration efforts across multiple regions yields population growth rates above 1 with smaller simulated improvements in habitat per region than single-region strategies.5. Synthesis and applications: These findings suggest that conservation investment in projects across the full monarch range will be more effective than focusing on one or a few regions, and will require international cooperation across many land use categories.
19. Fate of semi-natural grassland in England between 1960 and 2013: A test of national conservation policy
Directory of Open Access Journals (Sweden)
Lucy E. Ridding
2015-07-01
Full Text Available It is well documented that significant losses in semi-natural grassland occurred across Europe during the second half of the twentieth century. However, comparatively few studies have investigated and quantified the fate of large numbers of individual grassland areas. This is important for understanding the causes of decline, and consequently establishing new policies to conserve and restore lost habitats. This study addresses this problem; GIS was used to compare historic survey data collected between 1960 and 1981 with two contemporary spatial datasets of habitats in England. The datasets included the Priority Habitats Inventory 2013 and the Land Cover Map 2007 and this was undertaken for different types of semi-natural grassland across England. Considerable decreases occurred across the different grassland types, with a loss of 47% of studied semi-natural grasslands sites in England over 32–53 years. Of this, the majority of grassland was lost to conversion to agriculturally-improved grassland or arable cultivation, 45% and 43% respectively. Changes to woodland and urban areas were also evident, but on a much smaller scale. Sites receiving statutory protection as a Site of Special Scientific Interest were found to have retained more grassland (91%, compared with non-protected sites (27%, thus highlighting the effectiveness of this aspect of current conservation policy in England, and the need for this to continue in the future.
20. An examination of the effects of land use changes on nature conservation rulings in Ceşme peninsula, Turkey.
Science.gov (United States)
Gülgün, Bahriye; Türkyilmaz, Bahar; Bolca, Mustafa; Ozen, Fulsen
2009-04-01
Because of their intense vegetation and the fact that they include areas of coastline, deltas situated in the vicinity of big cities are areas of great attraction for people who wish to get away from in a crowded city. However, coasts, with their fertile soil and unique flora and fauna, need to be protected. In order for the use of such areas to be planned in a sustainable way by local authorities, there is a need for detailed data about these regions. In this study, the changes in land use of the area between Topburnu and Uçburun Musa Bey Harbour on the Ceşme peninsula, which is to the immediate west of Turkey's third largest city Izmir, from 1976 up to the present day, were investigated. In the study, using aerial photographs taken in 1976, 1995 and 2000 and an IKONOS satellite image from the year 2007, the natural and cultural characteristics of the region and changes in the coastline were determined spatially. Using aerial photographs from 1976, 1995 and 2000 and an IKONOS satellite image from the year 2007, together with "1/25,000 scale Conservation-Oriented Development Plans" prepared in 1979, 1990 and 2000 by the committee for the Preservation of Natural and Cultural Entities attached to the Ministry of Culture and Tourism of the Turkish Republic, the natural and cultural characteristics of the region and the land use changes and their connection with conservation rulings were determined spatially. In this study, spatial changes in land use over the years were compared with changing conservation rulings over the years and the emerging results have brought a new perspective to the subject in contrast to other similar studies.
1. Conservation and diversity of Foxp2 expression in muroid rodents: Functional implications
OpenAIRE
Campbell, Polly; Reep, Roger L.; Stoll, Margaret L.; Ophir, Alexander G.; Phelps, Steven M.
2009-01-01
FOXP2, the first gene causally linked to a human language disorder, is implicated in song acquisition, production and perception in oscine songbirds, the evolution of speech and language in hominids and the evolution of echolocation in bats. Despite the evident relevance of Foxp2 to vertebrate acoustic communication, a comprehensive description of neural expression patterns is currently lacking in mammals. Here we use immunocytochemistry to systematically describe the neural distribution of F...
2. Natural R parity conservation with horizontal symmetries a four generation model
CERN Document Server
Berezhiani, Z G; Berezhiani, Zurab; Nardi, Enrico
1995-01-01
The absence of R parity violating operators can be naturally ensured in the presence of a SU(N)_H\\ (N=4,6...) horizontal gauge symmetry, independently of the vertical gauge group. We study an extension of the supersymmetric standard model with four families and gauged SU(4)_H. Beyond preserving R parity, the model gives rise to the realistic fermion mass matrices which naturally ensure the heaviness of the fourth family fermions b',t',\\tau',\
3. Assessing bias and knowledge gaps on seed ecology research: implications for conservation agenda and policy.
Science.gov (United States)
Ribeiro, Guilherme V T; Teixido, Alberto L; Barbosa, Newton P U; Silveira, Fernando A O
2016-10-01
Sampling biases permeate ecological research and result in knowledge gaps that have vital consequences for conservation planning. The consequences of knowledge gaps on species identity and distribution (the Wallacean and Linnean shortfalls, respectively) have become apparent recently, but we know little about the extent that research biases and knowledge gaps on traits that influence species' niches (the Hutchinsonian shortfall) affect conservation policy. To examine whether knowledge of species' traits based on seed ecology is geographically, phylogenetically, and ecologically biased, we retrieved research data on seed germination, seed dormancy, seed dispersal, seed banks, seed predation, and seed removal from a database of 847 papers, 1648 species, and 5322 cases. Brazil was selected as a model system for megadiverse, undersampled countries. Kernel density maps showed that research was geographically biased towards highly populated sites, with vast areas remaining historically unexplored. We also show that research was clustered into protected areas. We detected a significant positive phylogenetic bias at genus-level, indicating research concentration in few genera and lower relative bias rates for many herbaceous genera. Unexpectedly, information on seed banking was available for only 74 (3.4%) of threatened species, which suggests that information deficits are highest for species with critical needs for ex situ conservation strategies. Tree, fleshy-fruited, and biotic dispersal species were disproportionately overstudied. Our data indicate that information deficits on seed ecology preclude our ability to effectively restore ecosystems and to safeguard endangered species. We call for a systematic improvement of environmental agenda in which policy makers and scientists target sites, clades, and functional groups historically neglected. Lessons from developed countries and collaborative efforts will be important for megadiverse, underdeveloped countries to
4. Defining evolutionary boundaries across parapatric ecomorphs of Black Salamanders (Aneides flavipunctatus) with conservation implications.
Science.gov (United States)
Reilly, Sean B; Marks, Sharyn B; Jennings, W Bryan
2012-12-01
The accurate delimitation of evolutionary population units represents an important component in phylogeographic and conservation genetic studies. Here, we used a combined population assignment and historical demographic approach to study a complex of ecomorphologically distinctive populations of Black Salamanders (Aneides flavipunctatus) that are parapatrically distributed and meet at a three-way contact zone in north-western California. We used mitochondrial tree-based and multilocus clustering methods to evaluate a priori two- (Northern and Southern) and three (Northern, Coast and Inland) population hypotheses derived from previous studies. Mitochondrial results were consistent with the two- and three-population hypotheses, while the nDNA clustering results supported only the two-population hypothesis. Historical demographic analyses and mtDNA gene divergence estimates revealed that the Northern and Southern populations split during the Pliocene (2-5 Ma). Subdivision of the Southern population into Coast and Inland populations was estimated to be late Pleistocene (0.24 Ma), although our mtDNA results suggested a Pliocene divergence. Effective gene flow estimates (2N(e)m) suggest that either the two- or three-population hypotheses remain valid. However, our results unexpectedly revealed that the Northern population might instead represent two parapatric populations that separated nearly 4 Ma. These results are surprising because the Pliocene divergence between these ecomorphologically conservative forms is similar or older than for the ecomorphologically divergent Coast and Inland sister populations. We conclude that Black Salamanders in north-western California belong to at least three or four populations or species, and these all meet criteria for being Evolutionary Significant Units or 'ESUs' and therefore warrant conservation consideration.
5. Residency and spatial use by reef sharks of an isolated seamount and its implications for conservation.
Science.gov (United States)
Barnett, Adam; Abrantes, Kátya G; Seymour, Jamie; Fitzpatrick, Richard
2012-01-01
Although marine protected areas (MPAs) are a common conservation strategy, these areas are often designed with little prior knowledge of the spatial behaviour of the species they are designed to protect. Currently, the Coral Sea area and its seamounts (north-east Australia) are under review to determine if MPAs are warranted. The protection of sharks at these seamounts should be an integral component of conservation plans. Therefore, knowledge on the spatial ecology of sharks at the Coral Sea seamounts is essential for the appropriate implementation of management and conservation plans. Acoustic telemetry was used to determine residency, site fidelity and spatial use of three shark species at Osprey Reef: whitetip reef sharks Triaenodon obesus, grey reef sharks Carcharhinus amblyrhynchos and silvertip sharks Carcharhinus albimarginatus. Most individuals showed year round residency at Osprey Reef, although five of the 49 individuals tagged moved to the neighbouring Shark Reef (~14 km away) and one grey reef shark completed a round trip of ~250 km to the Great Barrier Reef. Additionally, individuals of white tip and grey reef sharks showed strong site fidelity to the areas they were tagged, and there was low spatial overlap between groups of sharks tagged at different locations. Spatial use at Osprey Reef by adult sharks is generally restricted to the north-west corner. The high residency and limited spatial use of Osprey Reef suggests that reef sharks would be highly vulnerable to targeted fishing pressure and that MPAs incorporating no-take of sharks would be effective in protecting reef shark populations at Osprey and Shark Reef.
6. Snakes on the Balearic Islands: An Invasion Tale with Implications for Native Biodiversity Conservation
Science.gov (United States)
Sillero, Neftalí; Mateo, Jose A.; Carretero, Miguel A.
2015-01-01
Biological invasions are a major conservation threat for biodiversity worldwide. Islands are particularly vulnerable to invasive species, especially Mediterranean islands which have suffered human pressure since ancient times. In the Balearic archipelago, reptiles represent an outstanding case with more alien than native species. Moreover, in the last decade a new wave of alien snakes landed in the main islands of the archipelago, some of which were originally snake-free. The identification of the origin and colonization pathways of alien species, as well as the prediction of their expansion, is crucial to develop effective conservation strategies. In this study, we used molecular markers to assess the allochthonous status and the putative origin of the four introduced snake species (Hemorrhois hippocrepis, Malpolon monspessulanus, Macroprotodon mauritanicus and Rhinechis scalaris) as well as ecological niche models to infer their patterns of invasion and expansion based on current and future habitat suitability. For most species, DNA sequence data suggested the Iberian Peninsula as the potential origin of the allochthonous populations, although the shallow phylogeographic structure of these species prevented the identification of a restricted source-area. For all of them, the ecological niche models showed a current low habitat suitability in the Balearic, which is however predicted to increase significantly in the next few decades under climate change scenarios. Evidence from direct observations and spatial distribution of the first-occurrence records of alien snakes (but also lizards and worm lizards) suggest the nursery trade, and in particular olive tree importation from Iberian Peninsula, as the main pathway of introduction of alien reptiles in the Balearic islands. This trend has been reported also for recent invasions in NE Spain, thus showing that olive trees transplantation may be an effective vector for bioinvasion across the Mediterranean. The
7. Residency and spatial use by reef sharks of an isolated seamount and its implications for conservation.
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Full Text Available Although marine protected areas (MPAs are a common conservation strategy, these areas are often designed with little prior knowledge of the spatial behaviour of the species they are designed to protect. Currently, the Coral Sea area and its seamounts (north-east Australia are under review to determine if MPAs are warranted. The protection of sharks at these seamounts should be an integral component of conservation plans. Therefore, knowledge on the spatial ecology of sharks at the Coral Sea seamounts is essential for the appropriate implementation of management and conservation plans. Acoustic telemetry was used to determine residency, site fidelity and spatial use of three shark species at Osprey Reef: whitetip reef sharks Triaenodon obesus, grey reef sharks Carcharhinus amblyrhynchos and silvertip sharks Carcharhinus albimarginatus. Most individuals showed year round residency at Osprey Reef, although five of the 49 individuals tagged moved to the neighbouring Shark Reef (~14 km away and one grey reef shark completed a round trip of ~250 km to the Great Barrier Reef. Additionally, individuals of white tip and grey reef sharks showed strong site fidelity to the areas they were tagged, and there was low spatial overlap between groups of sharks tagged at different locations. Spatial use at Osprey Reef by adult sharks is generally restricted to the north-west corner. The high residency and limited spatial use of Osprey Reef suggests that reef sharks would be highly vulnerable to targeted fishing pressure and that MPAs incorporating no-take of sharks would be effective in protecting reef shark populations at Osprey and Shark Reef.
8. Snakes on the Balearic islands: an invasion tale with implications for native biodiversity conservation.
Science.gov (United States)
Silva-Rocha, Iolanda; Salvi, Daniele; Sillero, Neftalí; Mateo, Jose A; Carretero, Miguel A
2015-01-01
Biological invasions are a major conservation threat for biodiversity worldwide. Islands are particularly vulnerable to invasive species, especially Mediterranean islands which have suffered human pressure since ancient times. In the Balearic archipelago, reptiles represent an outstanding case with more alien than native species. Moreover, in the last decade a new wave of alien snakes landed in the main islands of the archipelago, some of which were originally snake-free. The identification of the origin and colonization pathways of alien species, as well as the prediction of their expansion, is crucial to develop effective conservation strategies. In this study, we used molecular markers to assess the allochthonous status and the putative origin of the four introduced snake species (Hemorrhois hippocrepis, Malpolon monspessulanus, Macroprotodon mauritanicus and Rhinechis scalaris) as well as ecological niche models to infer their patterns of invasion and expansion based on current and future habitat suitability. For most species, DNA sequence data suggested the Iberian Peninsula as the potential origin of the allochthonous populations, although the shallow phylogeographic structure of these species prevented the identification of a restricted source-area. For all of them, the ecological niche models showed a current low habitat suitability in the Balearic, which is however predicted to increase significantly in the next few decades under climate change scenarios. Evidence from direct observations and spatial distribution of the first-occurrence records of alien snakes (but also lizards and worm lizards) suggest the nursery trade, and in particular olive tree importation from Iberian Peninsula, as the main pathway of introduction of alien reptiles in the Balearic islands. This trend has been reported also for recent invasions in NE Spain, thus showing that olive trees transplantation may be an effective vector for bioinvasion across the Mediterranean. The
9. Disentangling evolutionary signals: conservation, specificity determining positions and coevolution. Implication for catalytic residue prediction
DEFF Research Database (Denmark)
Teppa, Elin; Wilkins, Angela D.; Nielsen, Morten
2012-01-01
to the prediction system. Conclusions: This work contributes to the understanding of the different signals of evolution and also shows that it is possible to improve the detection of catalytic residues by integrating structural and higher order sequence evolutionary information with sequence conservation....... predictive potential compared to others when it comes to, in particular, the identification of catalytic residues (CR) in proteins. Using a large set of enzymatic protein families and measures based on different evolutionary signals, we sought to break up the different components of the information content...
10. Amphibians and disease: Implications for conservation in the Greater Yellowstone Ecosystem
Science.gov (United States)
Corn, P.S.
2007-01-01
The decline of amphibian populations is a world-wide phenomenon that has received increasing attention since about 1990. In 2004, the World Conservation Union’s global amphibian assessment concluded that 48% of the world’s 5,743 described amphibian species were in decline, with 32% considered threatened (Stuart et al. 2004). Amphibian declines are a significant issue in the western United States, where all native species of frogs in the genus Rana and many toads in the genus Bufo are at risk, particularly those that inhabit mountainous areas (Corn 2003a,b; Bradford 2005).
11. [Diversity, natural history and conservation of mammals from San Vito de Coto Brus, Costa Rica].
Science.gov (United States)
Pacheco, Jesús; Ceballos, Gerardo; Daily, Gretchen C; Ehrlich, Paul R; Suzán, Gerardo; Rodríguez-Herrera, Bernal; Marcé, Erika
2006-03-01
Although Costa Rica has been biologically well studied, few areas have complete mammal inventories, which are essential for ecological studies and conservation. The San Vito region is considered among the most important for scientific research in the country because of the presence of the Wilson Botanical Garden and Las Cruces. However, the knowledge of its mammalian fauna is incomplete. We extensively studied the mammals of San Vito, compiled a checklist, and evaluated its composition, relative abundance, habitat distribution, and conservation status. We recorded 105 species, representing 85 genera, 29 families, and 10 orders. Non-volant mammals represented 62 species, 59 genera, 23 families, and 9 orders. Bats belonged to 6 families, 26 genera and 43 species. The extensive deforestation and hunting have caused the extinction of seven species, but the region still supports, surprisingly, a relatively high number of species, most of which are rare. Few species are common and abundant. Species richness was higher in forest, and forest fragments; fewer species were found in coffee plantations, induced grasslands, and secondary vegetation. Around 21% (13 species) are included in the IUCN red book. Three species are considered endangered (Saimiri oerstedii, Tapirus bairdii, and Sylvilagus dicei), and two threatened (Myrmecophaga trydactila and Caluromys derbianus), of which two (T. bairdii and M. trydactila) are locally extinct. The other species in IUCN are either of low risk (i.e. Chironectes minimus) or data deficient (Lontra longicaudis). Additionally, 24 species (39%) are included in CITES.
12. Ecosystem implications of conserving endemic versus eradicating introduced large herbivores in the Galapagos Archipelago
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Bastille-Rousseau, Guillaume; Gibbs, James P.; Campbell, Karl; Yackulic, Charles B.; Blake, Stephen
2017-01-01
Restoration of damaged ecosystems through invasive species removal and native species conservation is an increasingly common practice in biodiversity conservation. Estimating the degree of ecosystem response attributable specifically to eradication of exotic herbivores versus restoration of native herbivores is often difficult and is complicated by concurrent temporal changes in other factors, especially climate. We investigated the interactive impacts of native mega-herbivores (giant tortoises) and the eradication of large alien herbivores (goats) on vegetation productivity across the Galapagos Archipelago. We examined archipelago-wide patterns of Normalized Difference Vegetation Index (NDVI) as a proxy for vegetation productivity between 2001 and 2015 and evaluated how goat and historical and current tortoise occurrence influenced productivity. We used a breakpoint analysis to detect change in trends in productivity from five targeted areas following goat eradication. We found a positive association between tortoise occurrence and vegetation productivity and a negative association with goat occurrence. We also documented an increase in plant productivity following goat removal with recovery higher in moister regions than in arid region, potentially indicating an alternate stable state has been created in the latter. Climate variation also contributed to the detected improvement in productivity following goat eradication, sometimes obscuring the effect of eradication but more usually magnifying it by up to 300%. Our work offers perspectives regarding the effectiveness and outcomes of eradicating introduced herbivores and re-introducing native herbivores, and the merits of staging them simultaneously in order to restore critical ecosystem processes such as vegetation productivity.
13. Land planarian assemblages in protected areas of the interior atlantic forest: implications for conservation.
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Lisandro Negrete
Full Text Available Land planarians are an interesting group of free-living flatworms that can be useful as bioindicators because of their high sensitivity to environmental changes and low dispersal capacity. In this study, we describe and compare assemblages of land planarians from areas with different conservation degrees of the Interior Atlantic Forest (Misiones, Argentina, and assess factors that could be related to their abundance and richness. Eight sites were tracked in search of land planarians in Reserva de Vida Silvestre Urugua-í (RVSU and Campo Anexo Manuel Belgrano (CAMB. Diurnal and nocturnal surveys were performed in each site along nine sampling campaigns. We collected 237 individuals belonging to 18 species of the subfamily Geoplaninae. All sites were dominated by Geoplana sp. 1 and Pasipha hauseri. The richness estimators showed that there would be more species in RVSU than in CAMB. The abundance and richness of land planarians was high during the night and after rainfalls, suggesting an increased activity of flatworms under such conditions. The abundance and richness of land planarians were also related to the conservation condition of the sites. Disturbed sites showed less abundance and richness, and were segregated from non-disturbed ones by nmMDS analysis. Beta diversity between sites was higher than expected, indicating that the species turnover between sites contributed more to the total richness (gamma diversity than the alpha diversity.
14. Asymmetrical Contributions to the Tragedy of the Commons and Some Implications for Conservation
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Jennifer Jacquet
2013-03-01
Full Text Available In Garrett Hardin’s popular essay on “The Tragedy of the Commons”, he presents a model of a shared commons where herdsmen graze their cattle to illustrate the tension between group and self-interest that characterizes so many social dilemmas. However, Hardin is not explicit that consumption can actually vary widely among herdsman, although later, when discussing population growth, he clarifies that “people vary”. People do indeed vary, and here we explore further the prevalence of asymmetrical contributions to the tragedy of the commons. We also provide several examples to demonstrate that asymmetries have been frequently underappreciated by conservation initiatives. Given that many of today’s major environmental problems, such as climate change, freshwater shortages, and overfishing, are problems of users or groups of users over-consuming common resources asymmetrically, we believe identifying patterns of consumption is a necessary first step in solving any social dilemma, and can help elucidate priority areas for conservation.
15. Estimating golden-cheeked warbler immigration: Implications for the spatial scale of conservation
Science.gov (United States)
Duarte, A.; Weckerly, F.W.; Schaub, M.; Hatfield, Jeffrey S.
2016-01-01
Understanding the factors that drive population dynamics is fundamental to species conservation and management. Since the golden-cheeked warbler Setophaga chrysoparia was first listed as endangered, much effort has taken place to monitor warbler abundance, occupancy, reproduction and survival. Yet, despite being directly related to local population dynamics, movement rates have not been estimated for the species. We used an integrated population model to investigate the relationship between immigration rate, fledging rate, survival probabilities and population growth rate for warblers in central Texas, USA. Furthermore, using a deterministic projection model, we examined the response required by vital rates to maintain a viable population across varying levels of immigration. Warbler abundance fluctuated with an overall positive trend across years. In the absence of immigration, the abundance would have decreased. However, the population could remain viable without immigration if both adult and juvenile survival increased by almost half or if juvenile survival more than doubled. We also investigated the response required by fledging rates across a range of immigration in order to maintain a viable population. Overall, we found that immigration was required to maintain warbler target populations, indicating that warbler conservation and management programs need to be implemented at larger spatial scales than current efforts to be effective. This study also demonstrates that by using limited data within integrated population models, biologists are able to monitor multiple key demographic parameters simultaneously to gauge the efficacy of strategies designed to maximize warbler viability in a changing landscape.
16. Land Planarian Assemblages in Protected Areas of the Interior Atlantic Forest: Implications for Conservation
Science.gov (United States)
Negrete, Lisandro; Colpo, Karine D.; Brusa, Francisco
2014-01-01
Land planarians are an interesting group of free-living flatworms that can be useful as bioindicators because of their high sensitivity to environmental changes and low dispersal capacity. In this study, we describe and compare assemblages of land planarians from areas with different conservation degrees of the Interior Atlantic Forest (Misiones, Argentina), and assess factors that could be related to their abundance and richness. Eight sites were tracked in search of land planarians in Reserva de Vida Silvestre Urugua-í (RVSU) and Campo Anexo Manuel Belgrano (CAMB). Diurnal and nocturnal surveys were performed in each site along nine sampling campaigns. We collected 237 individuals belonging to 18 species of the subfamily Geoplaninae. All sites were dominated by Geoplana sp. 1 and Pasipha hauseri. The richness estimators showed that there would be more species in RVSU than in CAMB. The abundance and richness of land planarians was high during the night and after rainfalls, suggesting an increased activity of flatworms under such conditions. The abundance and richness of land planarians were also related to the conservation condition of the sites. Disturbed sites showed less abundance and richness, and were segregated from non-disturbed ones by nmMDS analysis. Beta diversity between sites was higher than expected, indicating that the species turnover between sites contributed more to the total richness (gamma diversity) than the alpha diversity. PMID:24598934
17. Spatiotemporal dynamics of prairie wetland networks: power-law scaling and implications for conservation planning.
Science.gov (United States)
Wright, Christopher K
2010-07-01
Although habitat networks show promise for conservation planning at regional scales, their spatiotemporal dynamics have not been well studied, especially in climate-sensitive landscapes. Here I use satellite remote sensing to compile wetland habitat networks from the Prairie Pothole Region (PPR) of North America. An ensemble of networks assembled across a hydrologic gradient from deluge to drought and a range of representative dispersal distances exhibits power-law scaling of important topological parameters. Prairie wetland networks are "meso-worlds" with mean topological distance increasing faster with network size than small-world networks, but slower than a regular lattice (or "large world"). This scaling implies rapid dispersal through wetland networks without some of the risks associated with "small worlds" (e.g., extremely rapid propagation of disease or disturbance). Retrospective analysis of wetland networks establishes a climatic envelope for landscape connectivity in the PPR, where I show that a changing climate might severely impact metapopulation viability and restrict long-distance dispersal and range shifts. More generally, this study demonstrates an efficient approach to conservation planning at a level of abstraction addressing key drivers of the global biodiversity crisis: habitat fragmentation and climatic change.
18. High regional genetic differentiation of an endangered relict plant Craigia yunnanensis and implications for its conservation
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Jing Yang
2016-10-01
Full Text Available Of the genus Craigia, widespread in the Tertiary, only two relict species survived to modern times. One species is now possibly extinct and the other one, Craigia yunnanensis, is severely endangered. Extensive surveys have located six C. yunnanensis populations in Yunnan province, southwest China. Using fluorescent amplified fragment length polymorphism (AFLP, the genetic diversity and population structure of these populations were examined. It was found that genetic diversity of C. yunnanensis was moderate at the species level, but low at regional and population levels. Analysis of population structure showed significant genetic differentiation between Wenshan and Dehong regions, apparently representing two geographically isolated for long time refuges. There are also clear indications of isolation between populations, which, together with anthropogenically caused decline of population size, will lead to general loss of the species genetic variation with subsequent loss of adaptive potential. To conserve the genetic integrity of C. yunnanensis, we recommend that ex-situ conservation should include representative samples from every population of the two differentiated regions (e.g. Wenshan and Dehong. The crosses between individuals originated from different regions should be avoided because of a high risk of outbreeding depression. As all the extant populations of C. yunnanensis are in unprotected areas with strong anthropogenic impact, there is no alternative to reintroduction of C. yunnanensis into suitable protected locations.
19. Population genetics implications for the conservation of the Philippine Crocodile Crocodylus mindorensis Schmidt, 1935 (Crocodylia: Crocodylidae
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M.R.P. Hinlo
2014-03-01
Full Text Available Limited information is available on the Philippine Crocodile, Crocodylus mindorensis, concerning levels of genetic diversity either relative to other crocodilian species or among populations of the species itself. With only two known extant populations of C. mindorensis remaining, potentially low levels of genetic diversity are a conservation concern. Here, we evaluated 619 putative Philippine Crocodiles using a suite of 11 microsatellite markers, and compared them to four other crocodilian species sample sets. The two remaining populations from the island of Luzon and the island of Mindanao, representing the extremes of the former species’ distribution, appear to be differentiated as a result of genetic drift rather than selection. Both extant populations demonstrate lower genetic diversity and effective population sizes relative to other studied crocodilian species. The 57 C. mindorensis and C. porosus, Saltwater Crocodile, hybrids identified earlier from the Palawan Wildlife Rescue and Conservation Center were revalidated with a suite of 20 microsatellite loci; however, the timing of the event and the prevalence of hybridization in the species had yet to be fully determined. We defined the hybrids as one first cross from a C. porosus female and a C. mindorensis male and 56 C. mindorensis backcross individuals. This hybridization event appears to be confined to the PWRCC collection.
20. Rapid immune colloidal gold strip for cetacean meat restraining illegal trade and consumption: implications for conservation and public health.
Science.gov (United States)
Lo, Chieh; Chin, Li-Te; Chu, Chi-Shih; Wang, Yu-Ting; Chan, Kun-Wei; Yang, Wei-Cheng
2013-01-01
The consumption of cetacean meat is geographically common and often of undetermined sustainability. Besides, it can expose humans to contaminants and zoonotic pathogens. The illegality of possessing cetacean meat was likely under-reported in some countries due to lack of attention paid by the officials although DNA analysis of market products helped to show such practices. We developed two monoclonal antibodies against synthetic peptides of myoglobin (Mb) for constructing a rapid immune colloidal gold strip. Only cetacean Mb is capable of binding to both antibodies and presents positive signal while the Mb from other animals can bind only 1 of the antibodies and presents negative result. The strip for cetacean meat would be an applicable and cost-effective test for field inspectors and even the general public. It contributes to increase the reporting capacity and coverage of illegal cetacean meat possession, which has implications for global cetacean conservation and public health.
1. Challenge cost-share agreement between Polk County Conservation Board, Iowa Department of Natural Resources, and the U.S. Fish And Wildlife Service Neal Smith NWR
Data.gov (United States)
US Fish and Wildlife Service, Department of the Interior — This is a cost-share agreement between the U.S. Fish and Wildlife Service, Polk County Conservation Board, and the Iowa Department of Natural Resources in support...
2. Observational natural history and morphological taxonomy are indispensable for future challenges in biodiversity and conservation.
Science.gov (United States)
Staab, Michael; Ohl, Michael; Zhu, Chao-Dong; Klein, Alexandra-Maria
2015-01-01
Global biodiversity is rapidly declining, leading inevitably to a loss of ecosystem functionality when species and their associated life-history traits vanish. Unfortunately, even in the 21(st) century, a large proportion of Earth's species are yet unknown and also for most described species science lacks a deeper understanding of the functional role of species and thus of ecosystems. In this Addendum we use the recent discovery of a new spider wasp with a unique natural history as an example to emphasize the importance to conduct basic observational natural history and traditional taxonomic research. We aim to encourage such 'old-fashioned' research and biologists from various research fields to report the many fascinating phenomena holding valuable natural history information they may encounter. Such detailed knowledge on species, their life-history traits, and their trophic interactions will be crucial to reliably address the challenges global change brings to the persistence of ecosystems.
3. A Conservative Approach to the Management of a Dental Trauma for Immediate Natural Esthetics
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Mahesh Patni
2016-01-01
Full Text Available Introduction The fracture of front teeth is one of the routine presentations of traumatic injuries. The treatment of a fractured tooth involving the pulp includes root canal therapy and post placement followed by core build-up or by the extraction of the fractured tooth if it is not restorable. Case Presentation We report a case of an adult male who had traumatized both his maxillary central incisors following a blow experienced during domestic violence. He had lost a fractured fragment of the right central incisor, while the left incisor had complicated fractures with fragments retained attached to the soft tissue. Following radiovisiography (RVG, both incisors were conservatively treated in a single visit by reattachment and post and core techniques. Conclusions The treatment reported for reattachment of the tooth fractures and post and core techniques are reasonably easy while providing immediate and lasting results in patients’ regaining of social confidence and functionality.
4. A Conservative Approach to the Management of a Dental Trauma for Immediate Natural Esthetics
Science.gov (United States)
Mahesh Patni, Pallav; Jain, Pradeep; Jain Patni, Mona
2016-01-01
Introduction: The fracture of front teeth is one of the routine presentations of traumatic injuries. The treatment of a fractured tooth involving the pulp includes root canal therapy and post placement followed by core build-up or by the extraction of the fractured tooth if it is not restorable. Case Presentation: We report a case of an adult male who had traumatized both his maxillary central incisors following a blow experienced during domestic violence. He had lost a fractured fragment of the right central incisor, while the left incisor had complicated fractures with fragments retained attached to the soft tissue. Following radiovisiography (RVG), both incisors were conservatively treated in a single visit by reattachment and post and core techniques. Conclusions: The treatment reported for reattachment of the tooth fractures and post and core techniques are reasonably easy while providing immediate and lasting results in patients’ regaining of social confidence and functionality. PMID:27679787
5. Quotas Proposal to Conservation of a Protected Natural Area of Mexico
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Marco Antonio Almendarez-Hernández
2016-01-01
Full Text Available The Sierra La Laguna Biosphere Reserve (rbsla is a protected area and as such, is an instrument of environmental policy derived from national conservation strategies, therefore, an increase in fund programs aimed at improving management actions to contribute to this objective. In this sense, stated preference methods can be used as a management tool to control future tourism demand and avoid exceeding the carrying capacity of the reserve, as well as to determine a willingness to pay (wtp that could allow additional raise more funds to meet the objectives of environmental policy. wtp was estimated through Contingent Valuation Method using Probit model, our results showed that the median wtp varies between 69 and 108 pesos per person and can obtain additional economic benefits arising from the access of individuals to the Reserve which range between 26 and 41 million pesos.
6. Maternal antibody persistence: a neglected life-history trait with implications from albatross conservation to comparative immunology.
Science.gov (United States)
Garnier, R; Ramos, R; Staszewski, V; Militão, T; Lobato, E; González-Solís, J; Boulinier, T
2012-05-22
The evolution of different life-history strategies has been suggested as a major force constraining physiological mechanisms such as immunity. In some long-lived oviparous species, a prolonged persistence of maternal antibodies in offspring could thus be expected in order to protect them over their long growth period. Here, using an intergenerational vaccination design, we show that specific maternal antibodies can display an estimated half-life of 25 days post-hatching in the nestlings of a long-lived bird. This temporal persistence is much longer than previously known for birds and it suggests specific properties in the regulation of IgY immunoglobulin catabolism in such a species. We also show that maternal antibodies in the considered procellariiform species are functional as late as 20 days of age. Using a modelling approach, we highlight that the potential impact of such effects on population viability could be important, notably when using vaccination for conservation. These results have broad implications, from comparative immunology to evolutionary eco-epidemiology and conservation biology.
7. Non-migratory breeding by isolated green sea turtles ( Chelonia mydas) in the Indian Ocean: biological and conservation implications
Science.gov (United States)
Whiting, Scott D.; Murray, Wendy; Macrae, Ismail; Thorn, Robert; Chongkin, Mohammad; Koch, Andrea U.
2008-04-01
Green sea turtles ( Chelonia mydas) are renowned for their long-distance migrations but have less fame for short-distance migrations or non-migratory behavior. We present satellite telemetric evidence from Cocos (Keeling) Islands, Indian Ocean for the first predominantly non-migratory green sea turtle ( C. mydas) population. The mean migration distance from the nesting beach to the foraging grounds was 35.5 km with a maximum mean transit time of 3.4 days. The behavior of this population has major implications for our general understanding of green turtle behavior and their life cycle and for conservation. Firstly, these results indicate a level of juvenile or adult non-breeding homing behavior from the open ocean to foraging grounds adjacent to their natal nesting beach. Secondly, a non-migratory breeding phase reduces the consumption of reproductive energy utilized, potentially resulting in higher fecundity for this population. Thirdly, the close proximity of the nesting and foraging habitats allows for uniformity in management and conservation strategies rarely possible for wide-ranging green turtle populations.
8. Impacts of Tropical Forest Disturbance Upon Avifauna on a Small Island with High Endemism: Implications for Conservation
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Martin Thomas
2010-01-01
Full Text Available Tropical forests are rapidly being lost across Southeast Asia and this is predicted to have severe implications for many of the region′s bird species. However, relationships between forest disturbance and avifaunal assemblages remain poorly understood, particularly on small island ecosystems such as those found in the biodiversity ′hotspot′ of Wallacea. This study examines how avifaunal richness varies across a disturbance gradient in a forest reserve on Buton Island, southeast Sulawesi. Particular emphasis is placed upon examining responses in endemic and red-listed species with high conservation importance. Results indicate that overall avian richness increases between primary and 30-year-old regenerating secondary forest and then decreases through disturbed secondary forest, but is highest in cleared farmland. However, high species richness in farmland does not signify high species distinctiveness; bird community composition here differs significantly from that found in forest sites, and is poor in supporting forest specialists and endemic species. Certain large-bodied endemics such as the Knobbed Hornbill (Rhyticeros cassidix appear to be sensitive to moderate disturbance, with populations occurring at greatest density within primary forest. However, overall endemic species richness, as well as that of endemic frugivores and insectivores, is similar in primary and secondary forest types. Results indicate that well-established secondary forest in particular has an important role in supporting species with high conservational importance, possessing community composition similar to that found in primary forest and supporting an equally high richness of endemic species.
9. Crystal structure of the conserved domain of the DC lysosomal associated membrane protein: implications for the lysosomal glycocalyx
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Wilke Sonja
2012-07-01
Full Text Available Abstract Background The family of lysosome-associated membrane proteins (LAMP comprises the multifunctional, ubiquitous LAMP-1 and LAMP-2, and the cell type-specific proteins DC-LAMP (LAMP-3, BAD-LAMP (UNC-46, C20orf103 and macrosialin (CD68. LAMPs have been implicated in a multitude of cellular processes, including phagocytosis, autophagy, lipid transport and aging. LAMP-2 isoform A acts as a receptor in chaperone-mediated autophagy. LAMP-2 deficiency causes the fatal Danon disease. The abundant proteins LAMP-1 and LAMP-2 are major constituents of the glycoconjugate coat present on the inside of the lysosomal membrane, the 'lysosomal glycocalyx'. The LAMP family is characterized by a conserved domain of 150 to 200 amino acids with two disulfide bonds. Results The crystal structure of the conserved domain of human DC-LAMP was solved. It is the first high-resolution structure of a heavily glycosylated lysosomal membrane protein. The structure represents a novel β-prism fold formed by two β-sheets bent by β-bulges and connected by a disulfide bond. Flexible loops and a hydrophobic pocket represent possible sites of molecular interaction. Computational models of the glycosylated luminal regions of LAMP-1 and LAMP-2 indicate that the proteins adopt a compact conformation in close proximity to the lysosomal membrane. The models correspond to the thickness of the lysosomal glycoprotein coat of only 5 to 12 nm, according to electron microscopy. Conclusion The conserved luminal domain of lysosome-associated membrane proteins forms a previously unknown β-prism fold. Insights into the structure of the lysosomal glycoprotein coat were obtained by computational models of the LAMP-1 and LAMP-2 luminal regions.
10. New distributional records and conservation implications for the critically endangered greater bamboo lemur Prolemur simus.
Science.gov (United States)
Rakotonirina, Laingoniaina; Rajaonson, Andry; Ratolojanahary, Tianasoa; Rafalimandimby, Jean; Fanomezantsoa, Prosper; Ramahefasoa, Bellarmin; Rasolofoharivelo, Tovonanahary; Ravaloharimanitra, Maholy; Ratsimbazafy, Jonah; Dolch, Rainer; King, Tony
2011-01-01
To improve our knowledge of the distribution of the critically endangered greater bamboo lemur Prolemur simus, we surveyed 6 sites in eastern Madagascar. We found its characteristic feeding signs at 5 sites and made a direct sighting at one of these. One site represents a northern extension of 45 km of the known extant range of the species. Two sites are located in a forest corridor approximately halfway between the previously known southern and northern populations, therefore suggesting a broadly continuous distribution of the species within its range rather than the previously suspected distribution of two distinct populations separated by a distance of over 200 km. Our results illustrate the benefit of species-focussed surveys in determining the true distribution of endangered species, a realistic measure which is necessary in order to assess their current status and to prioritise long-term conservation interventions.
11. Plant diversity patterns in neotropical dry forests and their conservation implications.
Science.gov (United States)
Banda-R, Karina; Delgado-Salinas, Alfonso; Dexter, Kyle G; Linares-Palomino, Reynaldo; Oliveira-Filho, Ary; Prado, Darién; Pullan, Martin; Quintana, Catalina; Riina, Ricarda; Rodríguez M, Gina M; Weintritt, Julia; Acevedo-Rodríguez, Pedro; Adarve, Juan; Álvarez, Esteban; Aranguren B, Anairamiz; Arteaga, Julián Camilo; Aymard, Gerardo; Castaño, Alejandro; Ceballos-Mago, Natalia; Cogollo, Álvaro; Cuadros, Hermes; Delgado, Freddy; Devia, Wilson; Dueñas, Hilda; Fajardo, Laurie; Fernández, Ángel; Fernández, Miller Ángel; Franklin, Janet; Freid, Ethan H; Galetti, Luciano A; Gonto, Reina; González-M, Roy; Graveson, Roger; Helmer, Eileen H; Idárraga, Álvaro; López, René; Marcano-Vega, Humfredo; Martínez, Olga G; Maturo, Hernán M; McDonald, Morag; McLaren, Kurt; Melo, Omar; Mijares, Francisco; Mogni, Virginia; Molina, Diego; Moreno, Natalia Del Pilar; Nassar, Jafet M; Neves, Danilo M; Oakley, Luis J; Oatham, Michael; Olvera-Luna, Alma Rosa; Pezzini, Flávia F; Dominguez, Orlando Joel Reyes; Ríos, María Elvira; Rivera, Orlando; Rodríguez, Nelly; Rojas, Alicia; Särkinen, Tiina; Sánchez, Roberto; Smith, Melvin; Vargas, Carlos; Villanueva, Boris; Pennington, R Toby
2016-09-23
Seasonally dry tropical forests are distributed across Latin America and the Caribbean and are highly threatened, with less than 10% of their original extent remaining in many countries. Using 835 inventories covering 4660 species of woody plants, we show marked floristic turnover among inventories and regions, which may be higher than in other neotropical biomes, such as savanna. Such high floristic turnover indicates that numerous conservation areas across many countries will be needed to protect the full diversity of tropical dry forests. Our results provide a scientific framework within which national decision-makers can contextualize the floristic significance of their dry forest at a regional and continental scale. Copyright © 2016, American Association for the Advancement of Science.
12. Natural heritage of Taimyr: challenges for its conservation and sustainable use
NARCIS (Netherlands)
Mazurov, Y.L.; Ebbinge, B.S.; Pakina, A.; Pedroli, G.B.M.
2012-01-01
The article discusses the natural heritage of Taimyr (northern Siberia) within the perspective of the environmental conditions of the region. The assessment of its significance is based on the results of many years of Russian-Dutch ecological expeditions. Issues discussed are the responsibility for
13. Dispersion controlled natural attenuation : The role of conservative plume characteristics in reactive mixing processes
NARCIS (Netherlands)
Ham, Philip Andrew Sison
2006-01-01
The aim of this project was to gain a fundamental understanding into competing mixing processes involved in natural/enhanced attenuation; processes which occur chiefly in the transition zone of a contaminant plume. Analytical and numerical methods, in combination with laboratory and field data, were
14. Mitigation and Compensation under EU Nature Conservation Law in the Flemish Region: Beyond the Deadlock for Development Projects?
Directory of Open Access Journals (Sweden)
Hendrik Schoukens
2014-05-01
Full Text Available For years, the predicament of many of the European protected habitats and species in the Flemish Region, as in many other Member States, passed relatively unnoticed. The lack of proper rules and clear implementation rules fuelled the impression amongst project developers and planning authorities that the impacts of project developments on biodiversity did not really warrant closer assessment. However, in the past ten years, strict national case law has significantly altered this view. Faced with tighter judicial scrutiny, the Habitats and Birds Directives were seen as an important obstacle to project development. Hence mitigation and compensation have now come up as novel approaches to better align spatial aspirations with the conservation of nature. In reality, mitigation was often used as a cover-up for projects that would not fit the strict requirements enshrined in the derogatory clauses. Interestingly, the Belgian Council of State showed itself quite cautious in reasserting the lax view of some planning authorities on mitigation and compensation. In reviewing the legality of several new approaches to mitigation and compensation, the Belgian Council of State, which was initially very cautious in quashing decisions that would actually jeopardise major infrastructure developments, has rendered some compelling rulings on the specific application of mitigation and compensatory measures in a spatial planning context. By letting the objectives of EU nature conservation law prevail in the face of economic interests, the recent case law of the Belgian Council of State can be seen as a remarkable example of judicial environmental activism.
15. The Adaptation for Conservation Targets (ACT) framework: a tool for incorporating climate change into natural resource management.
Science.gov (United States)
Cross, Molly S; Zavaleta, Erika S; Bachelet, Dominique; Brooks, Marjorie L; Enquist, Carolyn A F; Fleishman, Erica; Graumlich, Lisa J; Groves, Craig R; Hannah, Lee; Hansen, Lara; Hayward, Greg; Koopman, Marni; Lawler, Joshua J; Malcolm, Jay; Nordgren, John; Petersen, Brian; Rowland, Erika L; Scott, Daniel; Shafer, Sarah L; Shaw, M Rebecca; Tabor, Gary M
2012-09-01
As natural resource management agencies and conservation organizations seek guidance on responding to climate change, myriad potential actions and strategies have been proposed for increasing the long-term viability of some attributes of natural systems. Managers need practical tools for selecting among these actions and strategies to develop a tailored management approach for specific targets at a given location. We developed and present one such tool, the participatory Adaptation for Conservation Targets (ACT) framework, which considers the effects of climate change in the development of management actions for particular species, ecosystems and ecological functions. Our framework is based on the premise that effective adaptation of management to climate change can rely on local knowledge of an ecosystem and does not necessarily require detailed projections of climate change or its effects. We illustrate the ACT framework by applying it to an ecological function in the Greater Yellowstone Ecosystem (Montana, Wyoming, and Idaho, USA)--water flows in the upper Yellowstone River. We suggest that the ACT framework is a practical tool for initiating adaptation planning, and for generating and communicating specific management interventions given an increasingly altered, yet uncertain, climate.
16. The role of evolutionarily conserved germ-line DH sequence in B-1 cell development and natural antibody production.
Science.gov (United States)
Vale, Andre M; Nobrega, Alberto; Schroeder, Harry W
2015-12-01
Because of N addition and variation in the site of VDJ joining, the third complementarity-determining region of the heavy chain (CDR-H3) is the most diverse component of the initial immunoglobulin antigen-binding site repertoire. A large component of the peritoneal cavity B-1 cell component is the product of fetal and perinatal B cell production. The CDR-H3 repertoire is thus depleted of N addition, which increases dependency on germ-line sequence. Cross-species comparisons have shown that DH gene sequence demonstrates conservation of amino acid preferences by reading frame. Preference for reading frame 1, which is enriched for tyrosine and glycine, is created both by rearrangement patterns and by pre-BCR and BCR selection. In previous studies, we have assessed the role of conserved DH sequence by examining peritoneal cavity B-1 cell numbers and antibody production in BALB/c mice with altered DH loci. Here, we review our finding that changes in the constraints normally imposed by germ-line-encoded amino acids within the CDR-H3 repertoire profoundly affect B-1 cell development, especially B-1a cells, and thus natural antibody immunity. Our studies suggest that both natural and somatic selection operate to create a restricted B-1 cell CDR-H3 repertoire.
17. Conservation of Endangered Lupinus mariae-josephae in Its Natural Habitat by Inoculation with Selected, Native Bradyrhizobium Strains
Science.gov (United States)
Navarro, Albert; Fos, Simón; Laguna, Emilio; Durán, David; Rey, Luis; Rubio-Sanz, Laura; Imperial, Juan; Ruiz-Argüeso, Tomás
2014-01-01
Lupinus mariae-josephae is a recently discovered endemism that is only found in alkaline-limed soils, a unique habitat for lupines, from a small area in Valencia region (Spain). In these soils, L. mariae-josephae grows in just a few defined patches, and previous conservation efforts directed towards controlled plant reproduction have been unsuccessful. We have previously shown that L. mariae-josephae plants establish a specific root nodule symbiosis with bradyrhizobia present in those soils, and we reasoned that the paucity of these bacteria in soils might contribute to the lack of success in reproducing plants for conservation purposes. Greenhouse experiments using L. mariae-josephae trap-plants showed the absence or near absence of L. mariae-josephae-nodulating bacteria in “terra rossa” soils of Valencia outside of L. mariae-josephae plant patches, and in other “terra rossa” or alkaline red soils of the Iberian Peninsula and Balearic Islands outside of the Valencia L. mariae-josephae endemism region. Among the bradyrhizobia able to establish an efficient symbiosis with L. mariae-josephae plants, two strains, LmjC and LmjM3 were selected as inoculum for seed coating. Two planting experiments were carried out in consecutive years under natural conditions in areas with edapho-climatic characteristics identical to those sustaining natural L. mariae-josephae populations, and successful reproduction of the plant was achieved. Interestingly, the successful reproductive cycle was absolutely dependent on seedling inoculation with effective bradyrhizobia, and optimal performance was observed in plants inoculated with LmjC, a strain that had previously shown the most efficient behavior under controlled conditions. Our results define conditions for L. mariae-josephae conservation and for extension to alkaline-limed soil habitats, where no other known lupine can thrive. PMID:25019379
18. Recruitment and Patch Establishment by Seed in the Seagrass Posidonia oceanica: Importance and Conservation Implications.
Science.gov (United States)
Balestri, Elena; Vallerini, Flavia; Lardicci, Claudio
2017-01-01
Seagrasses are declining globally, and deeper understanding is needed on the recruitment potential and distribution of new populations for many threatened species to support conservation planning in the face of climate change. Recruitment of Posidonia oceanica, a threatened seagrass endemic to the Mediterranean, has long been considered rare due to infrequent flowering, but mounting evidence demonstrates that the species is responding to a changing climate through greater reproductive effort. Due to the fragmentary information on recruit occurrence and distribution, little is known about reproductive success in the species and its contribution to persistence. We assembled P. oceanica recruitment data from published and unpublished sources, including our own, to examine the frequency and extent of recruitment events (establishment of seedlings in a site), seedling growth potential and habitat characteristics at recruitment sites. Results show that at least one recruitment event has occurred about every 3 years, and 18 localities were colonized at least one time since the first seedling record in 1986. Notably, consistently high seedling inputs were observed in four localities of the Western Mediterranean. Seedlings established mainly on unoccupied substrate areas along the coasts of islands, in sheltered sites and at shallower depths (recruitment is rare and usually unsuccessful for P. oceanica, and highlight the potential importance of recruitment for the long-term persistence and adaptation of the species to sea level rise predicted in the next century in the Mediterranean. Unfortunately, management actions have mainly focused on established meadows, ignoring the presence of recruits in outside areas. Therefore, it will be useful to identify and consider regeneration sites in designing future management strategies to improve seagrass conservation effectiveness.
19. Seeds of alpine plants are short lived: implications for long-term conservation.
Science.gov (United States)
Mondoni, Andrea; Probert, Robin J; Rossi, Graziano; Vegini, Emanuele; Hay, Fiona R
2011-01-01
Alpine plants are considered one of the groups of species most sensitive to the direct and indirect threats to ecosystems caused by land use and climate change. Collecting and banking seeds of plant species is recognized as an effective tool for providing propagating material to re-establish wild plant populations and for habitat repair. However, seeds from cold wet environments have been shown to be relatively short lived in storage, and therefore successful long-term seed conservation for alpine plants may be difficult. Here, the life spans of 69 seed lots representing 63 related species from alpine and lowland locations from northern Italy are compared. Seeds were placed into experimental storage at 45 °C and 60 % relative humidity (RH) and regularly sampled for germination. The time taken in storage for viability to fall to 50 % (p(50)) was determined using probit analysis and used as a measure of relative seed longevity between seed lots. Across species, p(50) at 45 °C and 60 % RH varied from 4·7 to 95·5 d. Seed lots from alpine populations/species had significantly lower p(50) values compared with those from lowland populations/species; the lowland seed lots showed a slower rate of loss of germinability, higher initial seed viability, or both. Seeds were progressively longer lived with increased temperature and decreased rainfall at the collecting site. Seeds of alpine plants are short lived in storage compared with those from lowland populations/related taxa. The lower resistance to ageing in seeds of alpine plants may arise from low selection pressure for seed resistance to ageing and/or damage incurred during seed development due to the cool wet conditions of the alpine climate. Long-term seed conservation of several alpine species using conventional seed banking methods will be problematic.
20. Pastoralist-predator interaction at the roof of the world: Conflict dynamics and implications for conservation
Directory of Open Access Journals (Sweden)
Jaffar Ud. Din
2017-06-01
Full Text Available Pastoralism and predation are two major concomitantly known facts and matters of concern for conservation biologists worldwide. Pastoralist-predator conflict constitutes a major social-ecological concern in the Pamir mountain range encompassing Afghanistan, Pakistan, and Tajikistan, and affects community attitudes and tolerance toward carnivores. Very few studies have been conducted to understand the dynamics of livestock predation by large carnivores like snow leopards (Panthera uncia and wolves (Canis lupus, owing to the region's remoteness and inaccessibility. This study attempts to assess the intensity of livestock predation (and resulting perceptions by snow leopards and wolves across the Afghani, Pakistani, and Tajik Pamir range during the period January 2008-June 2012. The study found that livestock mortality due to disease is the most serious threat to livestock (an average 3.5 animal heads per household per year and ultimately to the rural economy (an average of US$352 per household per year as compared to predation (1.78 animal heads per household per year, US$191 in the three study sites. Overall, 1419 (315 per year heads of livestock were reportedly killed by snow leopards (47% and wolves (53% in the study sites. People with comparatively smaller landholdings and limited earning options, other than livestock rearing, expressed negative attitudes toward both wolves and snow leopards and vice versa. Education was found to be an effective solution to dilute people's hatred for predators. Low public tolerance of the wolf and snow leopard in general explained the magnitude of the threat facing predators in the Pamirs. This will likely continue unless tangible and informed conservation measures like disease control and predation compensation programs are taken among others.
1. Conservation and implications of eukaryote transcriptional regulatory regions across multiple species
Directory of Open Access Journals (Sweden)
Deng Minghua
2008-12-01
Full Text Available Abstract Background Increasing evidence shows that whole genomes of eukaryotes are almost entirely transcribed into both protein coding genes and an enormous number of non-protein-coding RNAs (ncRNAs. Therefore, revealing the underlying regulatory mechanisms of transcripts becomes imperative. However, for a complete understanding of transcriptional regulatory mechanisms, we need to identify the regions in which they are found. We will call these transcriptional regulation regions, or TRRs, which can be considered functional regions containing a cluster of regulatory elements that cooperatively recruit transcriptional factors for binding and then regulating the expression of transcripts. Results We constructed a hierarchical stochastic language (HSL model for the identification of core TRRs in yeast based on regulatory cooperation among TRR elements. The HSL model trained based on yeast achieved comparable accuracy in predicting TRRs in other species, e.g., fruit fly, human, and rice, thus demonstrating the conservation of TRRs across species. The HSL model was also used to identify the TRRs of genes, such as p53 or OsALYL1, as well as microRNAs. In addition, the ENCODE regions were examined by HSL, and TRRs were found to pervasively locate in the genomes. Conclusion Our findings indicate that 1 the HSL model can be used to accurately predict core TRRs of transcripts across species and 2 identified core TRRs by HSL are proper candidates for the further scrutiny of specific regulatory elements and mechanisms. Meanwhile, the regulatory activity taking place in the abundant numbers of ncRNAs might account for the ubiquitous presence of TRRs across the genome. In addition, we also found that the TRRs of protein coding genes and ncRNAs are similar in structure, with the latter being more conserved than the former.
2. Cetacean range and climate in the eastern North Atlantic: future predictions and implications for conservation.
Science.gov (United States)
Lambert, Emily; Pierce, Graham J; Hall, Karen; Brereton, Tom; Dunn, Timothy E; Wall, Dave; Jepson, Paul D; Deaville, Rob; MacLeod, Colin D
2014-06-01
There is increasing evidence that the distributions of a large number of species are shifting with global climate change as they track changing surface temperatures that define their thermal niche. Modelling efforts to predict species distributions under future climates have increased with concern about the overall impact of these distribution shifts on species ecology, and especially where barriers to dispersal exist. Here we apply a bio-climatic envelope modelling technique to investigate the impacts of climate change on the geographic range of ten cetacean species in the eastern North Atlantic and to assess how such modelling can be used to inform conservation and management. The modelling process integrates elements of a species' habitat and thermal niche, and employs "hindcasting" of historical distribution changes in order to verify the accuracy of the modelled relationship between temperature and species range. If this ability is not verified, there is a risk that inappropriate or inaccurate models will be used to make future predictions of species distributions. Of the ten species investigated, we found that while the models for nine could successfully explain current spatial distribution, only four had a good ability to predict distribution changes over time in response to changes in water temperature. Applied to future climate scenarios, the four species-specific models with good predictive abilities indicated range expansion in one species and range contraction in three others, including the potential loss of up to 80% of suitable white-beaked dolphin habitat. Model predictions allow identification of affected areas and the likely time-scales over which impacts will occur. Thus, this work provides important information on both our ability to predict how individual species will respond to future climate change and the applicability of predictive distribution models as a tool to help construct viable conservation and management strategies.
3. Factors Affecting Diet Variation in the Pyrenean Rock Ptarmigan (Lagopus muta pyrenaica: Conservation Implications.
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Ricardo García-González
Full Text Available The Pyrenean rock ptarmigan (Lagopus muta pyrenaica lives at one of the southernmost limits of the ptarmigan range. Their small population sizes and the impacts of global changes are limiting factors in the conservation of this threatened subspecies. An effective conservation policy requires precise basic knowledge of a species' food and habitat requirements, information that is practically non-existent for this Pyrenean population. Here, we describe the diet of a ptarmigan population in the Eastern Pyrenees, the environmental factors influencing its variability and the relationship between diet floristic composition and quality. Diet composition was determined by microhistological analysis of faeces and diet quality was estimated from free-urate faecal N content. Our results show that grouse diet is based mainly on arctic-alpine shrubs of the Ericaceae family, as well as dwarf willows (Salix spp. and Dryas octopetala. The most frequently consumed plant species was Rhododendron ferrugineum, but its abundance in the diet was negatively related to the diet nitrogen content. Conversely, the abundance of Salix spp., grass leaves and arthropods increased the nitrogen content of the diet. Seasonality associated with snow-melting contributed the most to variability in the Pyrenean ptarmigan diet, differentiating winter from spring/summer diets. The latter was characterised by a high consumption of dwarf willows, flowers, arthropods and tender forb leaves. Geographic area and sex-age class influenced diet variability to a lesser extent. Current temperature increases in the Pyrenees due to global warming may reduce the persistence and surface area of snow-packs where preferred plants for rock ptarmigan usually grow, thus reducing food availability. The high consumption of Rh. ferrugineum characterised the diet of the Pyrenean population. Given the toxicity of this plant for most herbivores, its potential negative effect on Pyrenean ptarmigan populations
4. Movements and habitat use of an endangered snake, Hoplocephalus bungaroides (Elapidae): implications for conservation.
Science.gov (United States)
Croak, Benjamin M; Crowther, Mathew S; Webb, Jonathan K; Shine, Richard
2013-01-01
A detailed understanding of how extensively animals move through the landscape, and the habitat features upon which they rely, can identify conservation priorities and thus inform management planning. For many endangered species, information on habitat use either is sparse, or is based upon studies from a small part of the species' range. The broad-headed snake (Hoplocephalus bungaroides) is restricted to a specialized habitat (sandstone outcrops and nearby forests) within a small geographic range in south-eastern Australia. Previous research on this endangered taxon was done at a single site in the extreme south of the species' geographic range. We captured and radio-tracked 9 adult broad-headed snakes at sites in the northern part of the species' distribution, to evaluate the generality of results from prior studies, and to identify critical habitat components for this northern population. Snakes spent most of winter beneath sun-warmed rocks then shifted to tree hollows in summer. Thermal regimes within retreat-sites support the hypothesis that this shift is thermally driven. Intervals between successive displacements were longer than in the southern snakes but dispersal distances per move and home ranges were similar. Our snakes showed non-random preferences both in terms of macrohabitat (e.g., avoidance of some vegetation types) and microhabitat (e.g., frequent use of hollow-bearing trees). Despite many consistencies, the ecology of this species differs enough between southern and northern extremes of its range that managers need to incorporate information on local features to most effectively conserve this threatened reptile.
5. Movements and habitat use of an endangered snake, Hoplocephalus bungaroides (Elapidae: implications for conservation.
Directory of Open Access Journals (Sweden)
Benjamin M Croak
Full Text Available A detailed understanding of how extensively animals move through the landscape, and the habitat features upon which they rely, can identify conservation priorities and thus inform management planning. For many endangered species, information on habitat use either is sparse, or is based upon studies from a small part of the species' range. The broad-headed snake (Hoplocephalus bungaroides is restricted to a specialized habitat (sandstone outcrops and nearby forests within a small geographic range in south-eastern Australia. Previous research on this endangered taxon was done at a single site in the extreme south of the species' geographic range. We captured and radio-tracked 9 adult broad-headed snakes at sites in the northern part of the species' distribution, to evaluate the generality of results from prior studies, and to identify critical habitat components for this northern population. Snakes spent most of winter beneath sun-warmed rocks then shifted to tree hollows in summer. Thermal regimes within retreat-sites support the hypothesis that this shift is thermally driven. Intervals between successive displacements were longer than in the southern snakes but dispersal distances per move and home ranges were similar. Our snakes showed non-random preferences both in terms of macrohabitat (e.g., avoidance of some vegetation types and microhabitat (e.g., frequent use of hollow-bearing trees. Despite many consistencies, the ecology of this species differs enough between southern and northern extremes of its range that managers need to incorporate information on local features to most effectively conserve this threatened reptile.
6. The Quasispecies Nature and Biological Implications of the Hepatitis C Virus
OpenAIRE
Fishman, Sarah L; Branch, Andrea D.
2009-01-01
Many RNA viruses exist as a cloud of closely related sequence variants called a quasispecies, rather than as a population of identical clones. In this article, we explain the quasispecies nature of RNA viral genomes, and briefly review the principles of quasispecies dynamics and the differences with classical population genetics. We then discuss the current methods for quasispecies analysis and conclude with the biological implications of this phenomenon, focusing on the hepatitis C virus.
7. Threatened species to super-abundance: The unexpected international implications of successful goose conservation
DEFF Research Database (Denmark)
2017-01-01
Wild geese wintering in western Europe were declining by the 1930s probably due to loss of natural habitat and over exploitation through hunting, although the causes will never be known. Refuge provision and hunting restrictions from the 1950s enabled numbers to recover. Improved monitoring syste...
8. Implications of skull shape for the ecology and conservation biology of crocodiles
NARCIS (Netherlands)
Pearcy, Ashley
2011-01-01
Each species of crocodile has its own distinct head shape with its own well-adapted capacities for movement, force, strength, and in turn diet and habitat preferences suiting their niche. Different species of crocodilians with overlapping or matching natural ranges (sympatric species) show increased
9. A study of Taiwanese children's conceptions of and relation to nature: Curricular and policy implications
Science.gov (United States)
Dai, Amy Hsin-I.
The present study investigated children's conceptions of and relations to nature. Understanding the factors that influence them was the goal. The study used the Contextual Model of Learning as the theoretical framework to structure the research questions and data analysis to understand children's nature learning in the personal, sociocultural, and physical contexts that change over time. Twelve children aged 5 and 6 were prompted to draw a picture of themselves in nature. They were interviewed about the sources of those ideas and living experiences, and if they thought photographs of scenery were nature. These twelve children's parents also participated in a survey to study the family influence. I used interpretational analysis to seek for common patterns and themes. Scoring rubrics, coaxial comparison, constant comparison, and the theoretical framework were used to triangulate and investigate influential factors of children's ideas of nature. The study showed that children at this age already had developed a basic conception of what is nature, but also need to learn about the role of human beings in nature and the interrelations of nature in order to develop environmental education ideas. Most children also had a positive feeling toward nature. Children's definitions of nature were developed mainly from what parents and grandparents had told them and their firsthand exposure to nature. Only during the weekend did the children's families have time to visit nature. It was found that most parents in this study stated that they were inspired by nature and were very willing to take their children to nature settings. The most visited natural places that were reported visited were parks in the city and the mountains surrounding the city. However, very often parents missed teachable opportunities to make the experiences with nature meaningful to children. Implications of the study apply to curriculum designers, educators, urban planners, and parents. It is recommended
10. A Case for Conservative Management: Characterizing the Natural History of Radiographically Diagnosed Rathke Cleft Cysts.
Science.gov (United States)
Culver, Silas A; Grober, Yuval; Ornan, David A; Patrie, James T; Oldfield, Edward H; Jane, John A; Thorner, Michael O
2015-10-01
Rathke cleft cysts (RCCs) are benign embryonic remnants of the Rathke's pouch found in 13% to 33% of the general population. When symptomatic, they manifest themselves by compressing adjacent structures, causing pressure effects such as headache, visual disturbance, or pituitary hormone deficits. Most RCCs are asymptomatic, and their management remains controversial. Surgical resection has generally been indicated to treat symptomatic RCCs but carries the risk of complications. Our objective was to better characterize the outcomes for patients with presumed RCCs undergoing conservative management. This was a retrospective cohort study. The setting was a pituitary program at a university medical center. The participants were 75 patients with radiographically diagnosed RCCs. All brain magnetic resonance imaging (MRI) scans performed at the University of Virginia from 2006 through 2013 were searched for the words "Rathke cleft cyst," and pituitary clinic notes from 2007 to 2012 were reviewed for patients identified as probably having an RCC. Images for all patients were reviewed by the interpreting neuroradiologist, and those patients with at least 2 MRI scans were included. The dimensions of each cyst were assessed by the same neuroradiologist, and the volume of each cyst was analyzed as a function of the time from the first image obtained. A total of 75 patients (4-76 years old) met our inclusion criteria. The length of follow-up was 1 to 126 months (median 24 months). In 43 patients (57%) no detectable change in the size of their cysts was seen, in 21 patients (28%) cysts increased in size, and in 11 patients (15%) cysts decreased in size. The predicted mean cyst growth rate was not significantly different from 0. The increasingly prevalent use of brain imaging modalities such as MRI has resulted in an increase in the incidental discovery of pituitary lesions. Our study demonstrates that the majority of radiologically diagnosed RCCs remain unchanged or decrease in
11. Morphological and genetic variation in Cicindela lusitanica Mandl, 1935 (Coleoptera, Carabidae, Cicindelinae: implications for conservation
Directory of Open Access Journals (Sweden)
Serrano, A.
2003-12-01
Full Text Available The establishment of taxonomic and geographical boundaries is a common problem when analysing clinal distributions. This is of particular concern when the assessment of intraspecific groupings is required for conservation management. The tiger beetle Cicindela lusitanica Mandl, 1935 (Coleoptera, Carabidae is a typical case in which two recognised subspecies are distributed in a clinal latitudinal fashion in the dune systems along the Atlantic coast of Portugal. This habitat is increasingly under threat, and conservation measures are needed. We investigated the validity of the two named subspecies, based on a re-analysis of elytral and genitalic measurements using multivariate analysis. We also analysed variation in mitochondrial Cytochrome Oxidase I gene for a total of six populations along the cline. Multivariate analysis supported the idea of a morphological cline and revealed a clear distinction of the southernmost population and also some degree of distinctiveness of the most northern populations, partially supporting the recognised subspecific ranking. The mtDNA analysis identified two main groups corresponding to northern and southern populations. Both sets of markers showed that variation within the C. lusitanica assemblage is complex, with the boundaries between morphological and mtDNA groups not in agreement. However, populations at either end of the distributional range are clearly distinct from each other, and should be considered as provisional units for conservation programmes.El reconocimiento de límites taxonómicos y geográficos de la variabilidad observada es un problema habitual cuando se analizan distribuciones clinales. Esto es particularmente problemático cuando se requiere la determinación de agrupamientos intraespecíficos para tomar medidas de conservación. El cicindélido Cicindela lusitanica Mandl, 1935 (Coleoptera, Carabidae constituye un caso típico en el que dos subespecies reconocidas se hayan distribuidas a
12. Codon Usage Patterns in Corynebacterium glutamicum: Mutational Bias, Natural Selection and Amino Acid Conservation
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Guiming Liu
2010-01-01
Full Text Available The alternative synonymous codons in Corynebacterium glutamicum, a well-known bacterium used in industry for the production of amino acid, have been investigated by multivariate analysis. As C. glutamicum is a GC-rich organism, G and C are expected to predominate at the third position of codons. Indeed, overall codon usage analyses have indicated that C and/or G ending codons are predominant in this organism. Through multivariate statistical analysis, apart from mutational selection, we identified three other trends of codon usage variation among the genes. Firstly, the majority of highly expressed genes are scattered towards the positive end of the first axis, whereas the majority of lowly expressed genes are clustered towards the other end of the first axis. Furthermore, the distinct difference in the two sets of genes was that the C ending codons are predominate in putatively highly expressed genes, suggesting that the C ending codons are translationally optimal in this organism. Secondly, the majority of the putatively highly expressed genes have a tendency to locate on the leading strand, which indicates that replicational and transciptional selection might be invoked. Thirdly, highly expressed genes are more conserved than lowly expressed genes by synonymous and nonsynonymous substitutions among orthologous genes fromthe genomes of C. glutamicum and C. diphtheriae. We also analyzed other factors such as the length of genes and hydrophobicity that might influence codon usage and found their contributions to be weak.
13. Problem of fisher community and it’s implication on the management of South-East Aru conservation region
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Fernando D. W. Dangeubun
2013-11-01
Full Text Available . Ninety percent of Aru Islands community are fishers and mostly inhabit coastal areas and small islands. This area mostly comprises of small islands, having unique characteristics of marine resources and quite a lot of endemic species such as turtles, dugongs, and dolphins. This area also has quite complex and diverse resources ecosystem, resulting a variety of illegal practices in natural resources utilization. This study was aimed to analyze the fisher characteristics, and try to reveal social, economic and cultural factors which lead to natural resources degradation. Result shows that: (1 social problems faced by the community are the limited access to meet the needs of education, health, light, clean water, clothing, food and shelter as well as limited information of eco-friendly natural resources technology utilization; (2 this limited access triggers the community to increase revenue by optimizing the utilization of resources in the ecosystems of the island, mangrove, sea grass, coral reefs and open waters; (3 low income and high expenditure eliminate the implementation of local wisdom in the use of natural resources in sustainable way; and (4 the level of compliance and trustfulness of the community towards the leaders are still exist, hence can be used as a key component in motivating people in the management of South-East Aru conservation area.
14. Effect of pollination mode on progeny of Panicum coloratum var. makarikariense: Implications for conservation and breeding
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Lorena V. Armando
2017-09-01
Full Text Available Panicum coloratum var. makarikariense, a perennial grass native to Africa, is adapted to a wide range of soil and climatic conditions with potential to be used as forage in tropical and semi-arid regions around the world. Our objective was to understand how the pollination mode affects viable seed production and further survival of the progeny. We evaluated self- and open-pollinated progenies from different accessions by measuring the seed production of the parents and their germination performance, germination rate and seedling survival. Parents and progeny were also fingerprinted with Simple Sequence Repeats (SSR. Progeny produced through open-pollination resulted in significantly more filled seeds and superior seedling survival than self-pollination. These results indicate that accessions studied here rely heavily on cross-pollination, whereas the contribution of self-pollinated offspring to the population is likely to be low. SSR profiles showed that, on average, 85% of the progeny (arising from cross-pollination possessed paternal specific markers and 100% of them were genetically different from the maternal genotype. All plants examined had 4x = 36 chromosomes. Overall, our findings indicate that var. makarikariense is able to generate highly polymorphic progeny through segregation and recombination. This study provides reference information for the formulation of appropriate strategies for pasture germplasm management, conservation and development of breeding programs.
15. Micro-layers of polystyrene film preventing metal oxidation: implications in cultural heritage conservation
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Giambi, Francesca; Carretti, Emiliano; Dei, Luigi; Baglioni, Piero
2014-12-01
Protection of surfaces directly exposed to the detrimental action of degradative agents (i.e. oxygen, air pollutants and bacteria) is one of the most important challenges in the field of conservation of works of art. Metallic objects are subjected to specific surface corrosion phenomena that, over the years, make mandatory the research of innovative materials that should avoid the direct contact between the metal surface and the weathering agents. In this paper, the set-up, characterisation and application of a new reversible material for preserving metal artefacts are reported. Micro-layers constituted of low-adhesive polystyrene (PS) films obtained from recycling waste packaging materials made of expanded PS were studied. The morphology and thickness of PS films were characterised by optical, atomic force and scanning electron microscopy (SEM). A further check on thickness was carried out by means of visible spectrophotometry doping the films with a hydrophobic dye. Thermal properties of the PS micro-layers were studied by means of differential scanning calorimetry coupled with optical microscopy. Permeability of the PS films to water vapour was also determined. The potential of the low-adhesive PS films, that enabled an easy removal in case of film deterioration, for preventing metal oxidation was investigated on brass specimens by simulating standard artificial corrosion programmes. Morphological and chemical (coupling the energy-dispersive X-rays spectrometry to SEM measurements) analyses carried out on these metal samples showed promising results in terms of surface protection against corrosion.
16. Regional vegetation change and implications for local conservation: An example from West Cornwall (United Kingdom
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A. Kosanic
2015-07-01
Full Text Available This study tracks local vegetation change in West Cornwall (South West England within regional context, using historic herbarium (pre-1900 and recent vegetation records (post-1900. The focus centres on species lost from the region over the past century. For this study we used a collection of herbarium records published in 1909 (Davey’s “Flora of Cornwall” and contemporary records from the “New Atlas of British and Irish Flora” downloaded from the National Biodiversity Network (NBN, online database. Both data sets were spatially analysed using ArcGIS in order to detect local scale species loss. Our results showed that species loss was highest in the south (11 plant species, compared to the loss from middle areas (6 plant species and in the northern area (8 plant species of West Cornwall. Results on species change at the local scale were different to the changes that are happening at the national scale. Loss from West Cornwall was detected for two plant species, Mountain Melick (Melica nutans and Field Eryngo (Eryngium campestare. These key results amplify the importance of local scale research and conservation in order to protect ecosystems functioning, genetic diversity, ecosystem services and regional identity.
17. Genetic structure of Mediterranean chukar ( Alectoris chukar, Galliformes) populations: conservation and management implications
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Barbanera, Filippo; Marchi, Chiara; Guerrini, Monica; Panayides, Panicos; Sokos, Christos; Hadjigerou, Pantelis
2009-10-01
The chukar ( Alectoris chukar, Galliformes) is a species hunted throughout its native range from the East Mediterranean to Manchuria and in the USA, which hosts the world’s largest introduced population. This study aims to investigate the genetic structure of Mediterranean chukar populations to aid management decisions. We genotyped 143 specimens at two regions of the mitochondrial DNA (mtDNA: cytochrome b, control region) and eight loci of the microsatellite DNA. Samples were collected in northern (Limnos, Lesvos, Chios) and southern (Crete) Aegean islands (Greece) and Cyprus. We also carried out mtDNA-based comparison with chukars ( n = 124) from Asia (16 countries) and the USA (five states). We propose six management units for Mediterranean populations. Given their genetic integrity, Limnos and Cyprus, which host different subspecies, proved to be of primary conservation interest. We found exotic A. chukar mtDNA lineages in Lesvos, Chios and Crete and produced definitive genetic evidence for the Asian origin of the US chukars.
18. Studying fish social behavior and cognition: implications for fish welfare and conservation
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Rui F Oliveira
2015-12-01
Full Text Available Within vertebrates teleost fish are the most diverse and plastic taxa in terms of social behavior. With over 29,000 species described so far, one can find all different types of social organization, mating systems and parental care types. Moreover, it is relatively common to find variation of these characters within closely related species, which makes them suitable for comparative studies on the evolution of social behavior (e.g. variation in mating systems and parental care type in African cichlids. Fish are also champions of social plasticity, as can be illustrated by the flexible patterns of sexual expression, as in the case of protrandrous and protogynous sex-change, simultaneous hermaphroditism and intra-sexual variation in the form of discrete alternative male phenotypes. Complex cognitive abilities used in social interactions have also evolved in fish, such as individual recognition, transitive inference and social learning. Therefore, teleosts offer unique opportunities to study both the evolution and the function of social behavior and cognition. In this talk I will summarize the work that our lab has been doing to establish zebrafish as a model organism for the study of social behavior and cognition and I will illustrate how knowledge on this are can be applied to fish welfare and to conservation issues.
19. Evolution and Phylogenetic Diversity of Yam Species (Dioscorea spp.: Implication for Conservation and Agricultural Practices.
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Marie Florence Sandrine Ngo Ngwe
Full Text Available Yams (Dioscorea spp. consist of approximately 600 species. Presently, these species are threatened by genetic erosion due to many factors such as pest attacks and farming practices. In parallel, complex taxonomic boundaries in this genus makes it more challenging to properly address the genetic diversity of yam and manage its germplasm. As a first step toward evaluating and preserving the genetic diversity yam species, we use a phylogenetic diversity (PD approach that has the advantage to investigate phylogenetic relationships and test hypotheses of species monophyly while alleviating to the problem of ploidy variation within and among species. The Bayesian phylogenetic analysis of 62 accessions from 7 species from three regions of Cameroon showed that most Dioscorea sections were monophyletic, but species within sections were generally non-monophyletic. The wild species D. praehensilis and cultivated D. cayenensis were the species with the highest PD. At the opposite, D. esculenta has a low PD and future studies should focus on this species to properly address its conservation status. We also show that wild species show a stronger genetic structure than cultivated species, which potentially reflects the management of the yam germplasm by farmers. These findings show that phylogenetic diversity is a promising approach for an initial investigation of genetic diversity in a crop consisting of closely related species.
20. Evolution and Phylogenetic Diversity of Yam Species (Dioscorea spp.): Implication for Conservation and Agricultural Practices.
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Ngo Ngwe, Marie Florence Sandrine; Omokolo, Denis Ndoumou; Joly, Simon
2015-01-01
Yams (Dioscorea spp.) consist of approximately 600 species. Presently, these species are threatened by genetic erosion due to many factors such as pest attacks and farming practices. In parallel, complex taxonomic boundaries in this genus makes it more challenging to properly address the genetic diversity of yam and manage its germplasm. As a first step toward evaluating and preserving the genetic diversity yam species, we use a phylogenetic diversity (PD) approach that has the advantage to investigate phylogenetic relationships and test hypotheses of species monophyly while alleviating to the problem of ploidy variation within and among species. The Bayesian phylogenetic analysis of 62 accessions from 7 species from three regions of Cameroon showed that most Dioscorea sections were monophyletic, but species within sections were generally non-monophyletic. The wild species D. praehensilis and cultivated D. cayenensis were the species with the highest PD. At the opposite, D. esculenta has a low PD and future studies should focus on this species to properly address its conservation status. We also show that wild species show a stronger genetic structure than cultivated species, which potentially reflects the management of the yam germplasm by farmers. These findings show that phylogenetic diversity is a promising approach for an initial investigation of genetic diversity in a crop consisting of closely related species.
1. The structure of Mediterranean rocky reef ecosystems across environmental and human gradients, and conservation implications.
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Enric Sala
Full Text Available Historical exploitation of the Mediterranean Sea and the absence of rigorous baselines makes it difficult to evaluate the current health of the marine ecosystems and the efficacy of conservation actions at the ecosystem level. Here we establish the first current baseline and gradient of ecosystem structure of nearshore rocky reefs at the Mediterranean scale. We conducted underwater surveys in 14 marine protected areas and 18 open access sites across the Mediterranean, and across a 31-fold range of fish biomass (from 3.8 to 118 g m(-2. Our data showed remarkable variation in the structure of rocky reef ecosystems. Multivariate analysis showed three alternative community states: (1 large fish biomass and reefs dominated by non-canopy algae, (2 lower fish biomass but abundant native algal canopies and suspension feeders, and (3 low fish biomass and extensive barrens, with areas covered by turf algae. Our results suggest that the healthiest shallow rocky reef ecosystems in the Mediterranean have both large fish and algal biomass. Protection level and primary production were the only variables significantly correlated to community biomass structure. Fish biomass was significantly larger in well-enforced no-take marine reserves, but there were no significant differences between multi-use marine protected areas (which allow some fishing and open access areas at the regional scale. The gradients reported here represent a trajectory of degradation that can be used to assess the health of any similar habitat in the Mediterranean, and to evaluate the efficacy of marine protected areas.
2. Incidence, causes and consequences of pregnancy failure in viviparous lizards: implications for research and conservation settings.
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Hare, Kelly M; Cree, Alison
2010-01-01
Research on the causes of pregnancy failure in vertebrates has historically been mammal-focussed. However, live-birth (viviparity) has evolved multiple times, and is present in all other vertebrate taxa except Aves and Agnatha. Viviparous lizards (O. Squamata, excluding snakes and amphisbaenians) provide a valuable experimental group when studying major evolutionary events and some are also species of high conservation value. Consequently, both researchers and herpetoculturists often require high reproductive output from captive-held lizards. We reviewed the literature to determine potential or known causes of pregnancy failure for captive lizards. Pregnancy success across species averages approximately 86%, but varies extensively and does not appear to be related to embryonic stage when brought into captivity or level of placentation. Causes of pregnancy failure also vary among species, but correct thermal environments are vital to success, and providing adequate nutrition before vitellogenesis increases the number of viable offspring. A coordinated sequence of hormonal changes involving both pro-pregnancy and pro-labour factors is important for successful pregnancies, although uncertainty remains around the maternal concentrations of corticosterone that allow successful development. Several research areas commonly studied in mammals have yet to be explored or fully addressed in pregnant lizards, including impacts of toxins, parasites, UV light and nutritional quality. As viviparity has evolved over 100 times in lizards, and many different levels of placentation exist, pregnant lizards provide valuable models for studies in ecology and evolution and offer a useful comparison for studies on other viviparous vertebrates.
3. Phylogeography, phylogeny and hybridization in trichechid sirenians: Implications for manatee conservation
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Vianna, J.A.; Bonde, R.K.; Caballero, S.; Giraldo, J.P.; Lima, R.P.; Clark, A.; Marmontel, M.; Morales-Vela, B.; De Souza, M. J.; Parr, L.; Rodriguez-Lopez, M.A.; Mignucci-Giannoni, A. A.; Powell, J.A.; Santos, F.R.
2006-01-01
The three living species of manatees, West Indian (Trichechus manatus), Amazonian (Trichechus inunguis) and West African (Trichechus senegalensis), are distributed across the shallow tropical and subtropical waters of America and the western coast of Africa. We have sequenced the mitochondrial DNA control region in 330 Trichechus to compare their phylogeographic patterns. In T. manatus we observed a marked population structure with the identification of three haplotype clusters showing a distinct spatial distribution. A geographic barrier represented by the continuity of the Lesser Antilles to Trinidad Island, near the mouth of the Orinoco River in Venezuela, appears to have restricted the gene flow historically in T. manatus. However, for T. inunguis we observed a single expanding population cluster, with a high diversity of very closely related haplotypes. A marked geographic population structure is likely present in T. senegalensis with at least two distinct clusters. Phylogenetic analyses with the mtDNA cytochrome b gene suggest a clade of the marine Trichechus species, with T. inunguis as the most basal trichechid. This is in agreement with previous morphological analyses. Mitochondrial DNA, autosomal microsatellites and cytogenetic analyses revealed the presence of hybrids between the T. manatus and T. inunguis species at the mouth of the Amazon River in Brazil, extending to the Guyanas and probably as far as the mouth of the Orinoco River. Future conservation strategies should consider the distinct population structure of manatee species, as well as the historical barriers to gene flow and the likely occurrence of interspecific hybridization. ?? 2006 Blackwell Publishing Ltd.
4. The structure of Mediterranean rocky reef ecosystems across environmental and human gradients, and conservation implications
Science.gov (United States)
Sala, Enric; Ballesteros, Enric; Dendrinos, Panagiotis; Di Franco, Antonio; Ferretti, Francesco; Foley, David; Fraschetti, Simonetta; Friedlander, Alan M.; Garrabou, Joaquim; Guclusoy, Harun; Guidetti, Paolo; Halpern, Benjamin S.; Hereu, Bernat; Karamanlidis, Alexandros A.; Kizilkaya, Zafer; Macpherson, Enrique; Mangialajo, Luisa; Mariani, Simone; Micheli, Fiorenza; Pais, Antonio; Riser, Kristin; Rosenberg, Andrew A.; Sales, Marta; Selkoe, Kimberly A.; Starr, Rick; Tomas, Fiona; Zabala, Mikel
2012-01-01
Historical exploitation of the Mediterranean Sea and the absence of rigorous baselines makes it difficult to evaluate the current health of the marine ecosystems and the efficacy of conservation actions at the ecosystem level. Here we establish the first current baseline and gradient of ecosystem structure of nearshore rocky reefs at the Mediterranean scale. We conducted underwater surveys in 14 marine protected areas and 18 open access sites across the Mediterranean, and across a 31-fold range of fish biomass (from 3.8 to 118 g m-2). Our data showed remarkable variation in the structure of rocky reef ecosystems. Multivariate analysis showed three alternative community states: (1) large fish biomass and reefs dominated by non-canopy algae, (2) lower fish biomass but abundant native algal canopies and suspension feeders, and (3) low fish biomass and extensive barrens, with areas covered by turf algae. Our results suggest that the healthiest shallow rocky reef ecosystems in the Mediterranean have both large fish and algal biomass. Protection level and primary production were the only variables significantly correlated to community biomass structure. Fish biomass was significantly larger in well-enforced no-take marine reserves, but there were no significant differences between multi-use marine protected areas (which allow some fishing) and open access areas at the regional scale. The gradients reported here represent a trajectory of degradation that can be used to assess the health of any similar habitat in the Mediterranean, and to evaluate the efficacy of marine protected areas.
5. Seasonal habitat preference by the flagship species Testudo hermanni: Implications for the conservation of coastal dunes.
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Berardo, Fabiana; Carranza, Maria Laura; Frate, Ludovico; Stanisci, Angela; Loy, Anna
2015-05-01
In this study, we explored if, how, and when the European Union habitats (EU sensu Habitats Directive 92/43/CEE) are used by the flagship species Testudo hermanni in a well-preserved coastal dune system of the Italian peninsula. Radio telemetry data and fine-scale vegetation habitat mapping were used to address the following questions: (a) is each EU habitat used differentially by Hermann's tortoises? (b) is there any seasonal variation in this utilization pattern? (c) how does each habitat contribute to the ecological requirements of the tortoises? Nine tortoises were fitted with transmitters and monitored for the entire season of activity. The eight EU habitats present in the study area were surveyed and mapped using GIS. The seasonal preferential use or avoidance of each habitat was tested by comparing, through bootstrap tests, the proportion of habitat occupied (piTh) with the proportion of available habitat in the entire landscape (piL). The analysis of 340 spatial locations showed a marked preference for the Cisto-Lavanduletalia dune sclerophyllous scrubs (EU code 2260) and a seasonal selection of Juniperus macrocarpa bushes (EU code 2250(*)), wooded dunes with Pinus (EU code 2270) and mosaic of dune grasslands and sclerophyllous scrubs (EU codes 2230, 2240, 2260). Seasonal variation of habitat preference was interpreted in light of the different feeding, thermoregulation and reproductive needs of the tortoises. Our results stress the ecological value of EU coastal dune habitats and suggest prioritization of conservation efforts in these ecosystems.
6. Wildlife translocation: the conservation implications of pathogen exposure and genetic heterozygosity
Science.gov (United States)
2011-01-01
Background A key challenge for conservation biologists is to determine the most appropriate demographic and genetic management strategies for wildlife populations threatened by disease. We explored this topic by examining whether genetic background and previous pathogen exposure influenced survival of translocated animals when captive-bred and free-ranging bighorn sheep (Ovis canadensis) were used to re-establish a population that had been extirpated in the San Andres Mountains in New Mexico, USA. Results Although the free-ranging source population had significantly higher multi-locus heterozygosity at 30 microsatellite loci than the captive bred animals, neither source population nor genetic background significantly influenced survival or cause of death. The presence of antibodies to a respiratory virus known to cause pneumonia was associated with increased survival, but there was no correlation between genetic heterozygosity and the presence of antibodies to this virus. Conclusions Although genetic theory predicts otherwise, increased heterozygosity was not associated with increased fitness (survival) among translocated animals. While heterosis or genetic rescue effects may occur in F1 and later generations as the two source populations interbreed, we conclude that previous pathogen exposure was a more important marker than genetic heterozygosity for predicting survival of translocated animals. Every wildlife translocation is an experiment, and whenever possible, translocations should be designed and evaluated to test hypotheses that will further improve our understanding of how pathogen exposure and genetic variability influence fitness. PMID:21284886
7. Wildlife translocation: the conservation implications of pathogen exposure and genetic heterozygosity
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Penedo M Cecilia T
2011-02-01
Full Text Available Abstract Background A key challenge for conservation biologists is to determine the most appropriate demographic and genetic management strategies for wildlife populations threatened by disease. We explored this topic by examining whether genetic background and previous pathogen exposure influenced survival of translocated animals when captive-bred and free-ranging bighorn sheep (Ovis canadensis were used to re-establish a population that had been extirpated in the San Andres Mountains in New Mexico, USA. Results Although the free-ranging source population had significantly higher multi-locus heterozygosity at 30 microsatellite loci than the captive bred animals, neither source population nor genetic background significantly influenced survival or cause of death. The presence of antibodies to a respiratory virus known to cause pneumonia was associated with increased survival, but there was no correlation between genetic heterozygosity and the presence of antibodies to this virus. Conclusions Although genetic theory predicts otherwise, increased heterozygosity was not associated with increased fitness (survival among translocated animals. While heterosis or genetic rescue effects may occur in F1 and later generations as the two source populations interbreed, we conclude that previous pathogen exposure was a more important marker than genetic heterozygosity for predicting survival of translocated animals. Every wildlife translocation is an experiment, and whenever possible, translocations should be designed and evaluated to test hypotheses that will further improve our understanding of how pathogen exposure and genetic variability influence fitness.
8. Realisation of power systems and European nature conservation. The actual jurisdiction of the Federal Administrative Court; Realisierung von Energieanlagen und europaeischer Naturschutz. Die aktuelle Rechtsprechung des Bundesverwaltungsgerichts
Energy Technology Data Exchange (ETDEWEB)
Anger, Christoph [avocado rechtsanwaelte, Koeln (Germany)
2011-03-15
For a long time, the right of nature conservation and landscape conservation showed a shadowy existence in the approval of projects. Some actual decisions of the Supreme Court show that in the last years the nature conservation law developed to a central area of conflict in the licensing procedure. The contribution under consideration reports on the legal material using three selected problem areas from the law on the protection of area and law on the protection of species. On the one hand, the Federal Administrative Court (Leipzig, Federal Republic of Germany) always upgrades the requirements. However, on the other hand the Federal Administrative Court attaches great importance to practicability. The Federal Administrative Court often points to a way, how projects can be realized with a careful nature conservation related attendance also at difficult environmental conditions.
9. NATURAL HERITAGE OF TAIMYR: CHALLENGES FOR ITS CONSERVATION AND SUSTAINABLE USE
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Yuri Mazurov
2012-01-01
Full Text Available The article discusses the natural heritage of Taimyr (northern Siberia within the perspective of the environmental conditions of the region. The assessment of its significance is based on the results of many years of Russian-Dutch ecological expeditions. Issues discussed are the responsibility for the preservation of heritage, the interests of the local indigenous peoples, and the role of public authorities. Based on the results of a pilot project, the feasibility of developing ecotourism as one of the most effective forms of sustainable use of the heritage is demonstrated.
10. Protection reduces loss of natural land-cover at sites of conservation importance across Africa.
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Beresford, Alison E; Eshiamwata, George W; Donald, Paul F; Balmford, Andrew; Bertzky, Bastian; Brink, Andreas B; Fishpool, Lincoln D C; Mayaux, Philippe; Phalan, Ben; Simonetti, Dario; Buchanan, Graeme M
2013-01-01
There is an emerging consensus that protected areas are key in reducing adverse land-cover change, but their efficacy remains difficult to quantify. Many previous assessments of protected area effectiveness have compared changes between sets of protected and unprotected sites that differ systematically in other potentially confounding respects (e.g. altitude, accessibility), have considered only forest loss or changes at single sites, or have analysed changes derived from land-cover data of low spatial resolution. We assessed the effectiveness of protection in reducing land-cover change in Important Bird Areas (IBAs) across Africa using a dedicated visual interpretation of higher resolution satellite imagery. We compared rates of change in natural land-cover over a c. 20-year period from around 1990 at a large number of points across 45 protected IBAs to those from 48 unprotected IBAs. A matching algorithm was used to select sample points to control for potentially confounding differences between protected and unprotected IBAs. The rate of loss of natural land-cover at sample points within protected IBAs was just 42% of that at matched points in unprotected IBAs. Conversion was especially marked in forests, but protection reduced rates of forest loss by a similar relative amount. Rates of conversion increased from the centre to the edges of both protected and unprotected IBAs, but rates of loss in 20-km buffer zones surrounding protected IBAs and unprotected IBAs were similar, with no evidence of displacement of conversion from within protected areas to their immediate surrounds (leakage).
11. Small Unmanned Aerial Systems: Implications of the Evolving Legal Context for Use in Natural Resources Science and Management
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Walker, M. J.
2016-12-01
Small unmanned aerial systems (sUAS, also known as drones) potentially provide researchers and managers with the capacity to enhance temporal and spatial resolution of data sets for natural resources science and management. sUAS have been used for many types of data collection and have a partial definition in mass of the aircraft, ranging from 0.5 to Administration (FAA) recently faced the challenge of removing regulatory barriers to sUAS application while minimizing risk in the national airspace. The regulatory and legal framework developed for using sUAS in natural resources science and management has evolved from a very conservative approach prior in the first decade of the 21st century. FAA's recently revised operating rules for sUAS, significantly changing pilot certification requirements and operating rules in the national airspace. The next 2-5 years will bring advances in sUAS applications for science and management, building upon the accomplishments of users who complied with the former regulatory environment. We review the current operating rules (49 CFR, part 107) that apply specifically to sUAS and discuss the implications for researchers and managers. While part 107 relaxed many restrictions, it is important to understand the regulatory framework currently in place that encourages development of applications for sUAS while adhering to the mandate that the national airspace be safe and secure. We consider potential applications for natural resources science and management in the context of the recently released operating rules, especially with respect to training requirements and protocols for use.
12. Genetic characterization of wild swamp deer populations: ex situ conservation and forensics implications.
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Kumar, Ved Prakash; Shrivastwa, Anupam; Nigam, Parag; Kumar, Dhyanendra; Goyal, Surendra Prakash
2016-10-26
Swamp deer (Rucervus duvaucelii) is an endemic, Scheduled I species under the Wildlife (Protection) Act 1972, India. According to variations in antler size, it has been classified into three subspecies, namely Western (R. duvaucelii duvaucelii), Central (R. duvaucelii branderi), and Eastern (R. duvaucelii ranjitsinhii). For planning effective ex situ and in situ conservation of a wide-ranging species in different bioclimatic regions and in wildlife forensic, the use of genetic characterization in defining morpho/ecotypes has been suggested because of the geographic clines and reproductive isolation. In spite of these morphotypes, very little is known about the genetic characteristics of the three subspecies, hence no strict subspecies-based breeding plan for retaining the evolutionary characteristics in captive populations for subsequent re-introduction is available except for a few studies. We describe the genetic characteristics of these three subspecies using cytochrome b of the mtDNA genome (400 bp). The DNA sequence data indicated 11 variable sites within the three subspecies. Two paraphyletic clades, namely the Central India and Western-Eastern populations were found, whereas the Western and Eastern populations are monophyletic with a bootstrap value of 69% within the clade. We suggest the need of sorting these three subspecies using different molecular mtDNA markers in zoos for captive breeding purposes so as to retain the genetic diversity of the separate geographic clines and to use a subspecies-specific fixed-state nucleotide to assess the extent of poaching to avoid any population demography stochastically in India.
13. Conservation implications of physiological carry-over effects in bats recovering from white-nose syndrome.
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Davy, Christina M; Mastromonaco, Gabriela F; Riley, Julia L; Baxter-Gilbert, James H; Mayberry, Heather; Willis, Craig K R
2017-06-01
Although it is well documented that infectious diseases can pose threats to biodiversity, the potential long-term consequences of pathogen exposure on individual fitness and its effects on population viability have rarely been studied. We tested the hypothesis that pathogen exposure causes physiological carry-over effects with a pathogen that is uniquely suited to this question because the infection period is specific and time limited. The fungus Pseudogymnoascus destructans causes white-nose syndrome (WNS) in hibernating bats, which either die due to the infection while hibernating or recover following emergence from hibernation. The fungus infects all exposed individuals in an overwintering site simultaneously, and bats that survive infection during hibernation clear the pathogen within a few weeks following emergence. We quantified chronic stress during the active season, when bats are not infected, by measuring cortisol in bat claws. Free-ranging Myotis lucifugus who survived previous exposure to P. destructans had significantly higher levels of claw cortisol than naïve individuals. Thus, cryptic physiological carry-over effects of pathogen exposure may persist in asymptomatic, recovered individuals. If these effects result in reduced survival or reproductive success, they could also affect population viability and even act as a third stream in the extinction vortex. For example, significant increases in chronic stress, such as those indicated here, are correlated with reduced reproductive success in a number of species. Future research should directly explore the link between pathogen exposure and the viability of apparently recovered populations to improve understanding of the true impacts of infectious diseases on threatened populations. © 2016 Society for Conservation Biology.
14. Assessing ecological responses of wolves to wind power plants in Portugal: methodological constrains and conservation implications
Energy Technology Data Exchange (ETDEWEB)
Alvaras, Francisco; Rio-Maior, Helena; Roque, Sara; Nakamura, Monia; Cadete, Duarte; Pinto, Sara; Petrucci-Fonseca, Francisco
2011-07-01
Full text: Wind-power development has substantially increased in the last decade in Portugal and associated structures mostly overlap with wolf range, which raises major conservation concerns as a potential source of disturbance to this endangered carnivore. However, a comprehensive evaluation is greatly hampered by difficulties in studying wolf ecology and current lack of knowledge on the impacts of wind energy development on non-flying animals, especially large mammals. A research program was initiated in 2006, to: i) establish a methodological protocol for assessing impacts and monitoring wolf ecological responses to wind farms; ii) evaluate potential effects of wind farms on wolf space use and reproduction; iii) apply efficient mitigation and compensation measures. Field methods are based on howling and sign surveys, scat quantification through abundance indices and GPS telemetry. Preliminary results demonstrate that: i) road network built for wind-power development lead to a considerable increase in traffic, especially during construction of wind farms; ii) wolves continue to use areas with wind farms; iii) wolf presence tends to decrease with the cumulative number of turbines; iv) spatial responses of wolves to wind farms appear to depend on the number and proximity of turbines to important pack home sites and prey availability; v) wolves abandon or do not regularly use breeding sites located in the proximity of wind turbines; vi) wolves select breeding places at a lower altitude after wind farm construction, as a response to related disturbance in mountain ridges. Wind farms induce important changes in wolf space use, selection of and fidelity to reproduction sites and reproductive success. These behavioural and spatial responses may constrain connectivity within and between pack territories and increase reproductive instability, especially in already highly humanized landscapes as Portugal. Based on these findings, several preventive mitigation measures
15. Intraspecific phylogeography of Lasmigona subviridis (Bivalvia: Unionidae): Conservation implications of range discontinuity
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King, T.L.; Eackles, M.S.; Gjetvaj, B.; Hoeh, W.R.
1999-01-01
A nucleotide sequence analysis of the first internal transcribed spacer region (ITS-1) between the 5.8S and 18S ribosomal DNA genes (640 bp) and cytochrome c oxidase subunit I (COI) of mitochondrial DNA (mtDNA) (576 bp) was conducted for the freshwater bivalve Lasmigona subviridis and three congeners to determine the utility of these regions in identifying phylogeographic and phylogenetic structure. Sequence analysis of the ITS-1 region indicated a zone of discontinuity in the genetic population structure between a group of L. subviridis populations inhabiting the Susquehanna and Potomac Rivers and more southern populations. Moreover, haplotype patterns resulting from variation in the COI region suggested an absence of gene exchange between tributaries within two different river drainages, as well as between adjacent rivers systems. The authors recommend that the northern and southern populations, which are reproductively isolated and constitute evolutionarily significant lineages, be managed as separate conservation units. Results from the COI region suggest that, in some cases, unionid relocations should be avoided between tributaries of the same drainage because these populations may have been reproductively isolated for thousands of generations. Therefore, unionid bivalves distributed among discontinuous habitats (e.g. Atlantic slope drainages) potentially should be considered evolutionarily distinct. The DNA sequence divergences observed in the nuclear and mtDNA regions among the Lasmigona species were congruent, although the level of divergence in the COI region was up to three times greater. The genus Lasmigona, as represented by the four species surveyed in this study, may not be monophyletic.
16. Rapid decline of a grassland system and its ecological and conservation implications.
Directory of Open Access Journals (Sweden)
Gerardo Ceballos
Full Text Available One of the most important conservation issues in ecology is the imperiled state of grassland ecosystems worldwide due to land conversion, desertification, and the loss of native populations and species. The Janos region of northwestern Mexico maintains one of the largest remaining black-tailed prairie dog (Cynomys ludovicianus colony complexes in North America and supports a high diversity of threatened and endangered species. Yet, cattle grazing, agriculture, and drought have greatly impacted the region. We evaluated the impact of human activities on the Janos grasslands, comparing changes in the vertebrate community over the last two decades. Our results reveal profound, rapid changes in the Janos grassland community, demonstrating large declines in vertebrate abundance across all taxonomic groups. We also found that the 55,000 ha prairie dog colony complex has declined by 73% since 1988. The prairie dog complex has become increasingly fragmented, and their densities have shown a precipitous decline over the years, from an average density of 25 per ha in 1988 to 2 per ha in 2004. We demonstrated that prairie dogs strongly suppressed woody plant encroachment as well as created open grassland habitat by clearing woody vegetation, and found rapid invasion of shrubland once the prairie dogs disappeared from the grasslands. Comparison of grasslands and shrublands showed markedly different species compositions, with species richness being greatest when both habitats were considered together. Our data demonstrate the rapid decline of a grassland ecosystem, and documents the dramatic loss in biodiversity over a very short time period concomitant with anthropogenic grassland degradation and the decline of a keystone species.
17. Birdlime in Western Myanmar: Preparation, Use, and Conservation Implications for an Endemic Bird
Directory of Open Access Journals (Sweden)
Steven G. Platt
2012-12-01
Full Text Available Birdlimes are adhesive entangling compounds that passively capture birds by binding them to a substrate and rendering flight feathers useless. We investigated birdlime use among indigenous Chin hunters during a wildlife survey of Natma Taung National Park (NTNP in western Myanmar (May-June 2011. We found that birdlime is prepared from the sap of various banyan trees (Ficus spp. collected during the annual dry season (December-May. Birdlime is prepared by boiling sap to remove water, and the finished product is a readily malleable and extremely adhesive compound known locally as nghet phan te kaw (“bird glue”. Hunters employ four principal strategies when using birdlime: 1 limed sticks are placed at waterholes and springs; 2 limed sticks are placed in fruiting trees or nocturnal roost sites; 3 limed sticks are positioned at prominent vantage points and hunters mimic vocalizations to attract birds; 4 small insects (possibly termites are affixed to a limed pole and serve as bait to attract birds. Large numbers (>200 of birds can reportedly be captured during a single day by hunters using birdlime. At least 186 (63.9% of 291 species of birds occurring in Natma Taung National Park are thought to be vulnerable to this non-selective hunting strategy. The endangered white-browed nuthatch (Sitta victoriae Rippon Sittidae, a poorly-studied endemic species restricted to high elevation Oak-Rhododendron forest in NTNP, is vulnerable to birdliming, although the impact of hunting on populations remains unclear. We recommend that future investigations determine the sustainability of the Chin bird harvest by relating hunter off-take to recruitment and survivorship of nuthatches. If conservation action is deemed prudent, management plans should be developed in close collaboration with local Chin communities.
18. Bumble bee nest abundance, foraging distance, and host-plant reproduction: implications for management and conservation.
Science.gov (United States)
Geib, Jennifer C; Strange, James P; Galenj, Candace
2015-04-01
here (nest abundance, forager abundance, and foraging distance) could increase the usefulness of foraging worker inventories in nionitoring, managing, and conserving pollinator populations.
19. Extensive Clonality and Strong Differentiation in the Insular Pacific Tree Santalum insulare: Implications for its Conservation
Science.gov (United States)
LHUILLIER, EMELINE; BUTAUD, JEAN-FRANÇOIS; BOUVET, JEAN-MARC
2006-01-01
• Background and Aims The impact of evolutionary forces on insular systems is particularly exacerbated by the remoteness of islands, strong founder effects, small population size and the influence of biotic and abiotic factors. Patterns of molecular diversity were analysed in an island system with Santalum insulare, a sandalwood species endemic to eastern Polynesia. The aims were to evaluate clonality and to study the genetic diversity and structure of this species, in order to understand the evolutionary process and to define a conservation strategy. • Methods Eight nuclear microsatellites were used to investigate clonality, genetic variation and structure of the French Polynesian sandalwood populations found on ten islands distributed over three archipelagos. • Key Results It was found that 58 % of the 384 trees analysed were clones. The real size of the populations is thus dramatically reduced, with sometimes only one genet producing ramets by root suckering. The diversity parameters were low for islands (nA = 1·5–5·0; HE = 0·28–0·49). No departure from Hardy–Weinberg proportion was observed except within Tahiti island, where a significant excess of homozygotes was noted in the highland population. Genetic structure was characterized by high levels of differentiation between archipelagos (27 % of the total variation) and islands (FST = 0·50). The neighbour-joining tree did not discriminate the three archipelagos but separated the Society archipelago from the other two. • Conclusions This study shows that clonality is a frequent phenomenon in S. insulare. The genetic diversity within populations is lower than the values assessed in species distributed on the mainland, as a consequence of insularity. But this can also be explained by the overexploitation of sandalwood. The differentiation between archipelagos and islands within archipelagos is very high because of the limited gene flow due to oceanic barriers. Delineation of evolutionary
20. Higgs boson couplings in multi-doublet models with natural flavour conservation
Science.gov (United States)
Yagyu, Kei
2016-12-01
We investigate the deviation in the couplings of the standard model (SM) like Higgs boson (h) with a mass of 125 GeV from the prediction of the SM in multi-doublet models within the framework where flavour changing neutral currents at the tree level are naturally forbidden. After we present the general expressions for the modified gauge and Yukawa couplings for h, we show the correlation between the deviation in the Yukawa coupling for the tau lepton hτ+τ- and that for the bottom quark hb b bar under the assumption of a non-zero deviation in the hVV (V = W , Z) couplings in two Higgs doublet models (2HDMs) and three Higgs doublet models (3HDMs) as simple examples. We clarify the possible allowed prediction of the deviations in the 3HDMs which cannot be explained in the 2HDMs even taking into account the one-loop electroweak corrections to the Yukawa coupling.
1. Do Farmers Using Conventional and Non-Conventional Systems of Agriculture Have Different Perceptions of the Diversity of Wild Birds? Implications for Conservation.
Science.gov (United States)
Silva-Andrade, Horasa Lima; de Andrade, Luciano Pires; Muniz, Lauana Souza; Telino-Júnior, Wallace Rodrigues; Albuquerque, Ulysses Paulino; Lyra-Neves, Rachel Maria
2016-01-01
Farmers' perceptions of birds' interactions with agricultural production systems are fundamental to species conservation efforts. In the present study, we evaluated the perceptions of birds held by farmers who engage in conventional and non-conventional agricultural production processes and the implications of potential differences in these perceptions on species conservation. To accomplish this, data were collected using questionnaires, semi-structured interviews, and other complementary sources of information gathered from 191 farmers in northeastern Brazil. Although some similarities were identified among the farmers in their perceptions and local ecological knowledge (LEK) of birds, differences existed between the conventional and non-conventional farmers in their attitudes toward, conflicts with, and usage of bird species. Compared to the conventional farmers, the non-conventional farmers could identify more bird species, possessed more favorable attitudes toward birds, and engaged in practices more beneficial to the conservation of avifauna. The perceptions that were identified were related to the type of agriculture practiced, and such perceptions may affect the conservation of bird species. Therefore, the adoption of certain agricultural practices has important implications for conservation. Our results indicate the need for investment in public policies, programs and actions that account for farmers' knowledge and perceptions. Such investments will contribute to the development and adoption of practices supporting wild bird conservation in agricultural areas.
2. Do Farmers Using Conventional and Non-Conventional Systems of Agriculture Have Different Perceptions of the Diversity of Wild Birds? Implications for Conservation.
Directory of Open Access Journals (Sweden)
Full Text Available Farmers' perceptions of birds' interactions with agricultural production systems are fundamental to species conservation efforts. In the present study, we evaluated the perceptions of birds held by farmers who engage in conventional and non-conventional agricultural production processes and the implications of potential differences in these perceptions on species conservation. To accomplish this, data were collected using questionnaires, semi-structured interviews, and other complementary sources of information gathered from 191 farmers in northeastern Brazil. Although some similarities were identified among the farmers in their perceptions and local ecological knowledge (LEK of birds, differences existed between the conventional and non-conventional farmers in their attitudes toward, conflicts with, and usage of bird species. Compared to the conventional farmers, the non-conventional farmers could identify more bird species, possessed more favorable attitudes toward birds, and engaged in practices more beneficial to the conservation of avifauna. The perceptions that were identified were related to the type of agriculture practiced, and such perceptions may affect the conservation of bird species. Therefore, the adoption of certain agricultural practices has important implications for conservation. Our results indicate the need for investment in public policies, programs and actions that account for farmers' knowledge and perceptions. Such investments will contribute to the development and adoption of practices supporting wild bird conservation in agricultural areas.
3. Quantifying the spatial ecology of wide-ranging marine species in the Gulf of California: implications for marine conservation planning.
Science.gov (United States)
Anadón, José Daniel; D'Agrosa, Caterina; Gondor, Anne; Gerber, Leah R
2011-01-01
There is growing interest in systematic establishment of marine protected area (MPA) networks and representative conservation sites. This movement toward networks of no-take zones requires that reserves are deliberately and adequately spaced for connectivity. Here, we test the network functionality of an ecoregional assessment configuration of marine conservation areas by evaluating the habitat protection and connectivity offered to wide-ranging fauna in the Gulf of California (GOC, Mexico). We first use expert opinion to identify representative species of wide-ranging fauna of the GOC. These include leopard grouper, hammerhead sharks, California brown pelicans and green sea turtles. Analyzing habitat models with both structural and functional connectivity indexes, our results indicate that the configuration includes large proportions of biologically important habitat for the four species considered (25-40%), particularly, the best quality habitats (46-57%). Our results also show that connectivity levels offered by the conservation area design for these four species may be similar to connectivity levels offered by the entire Gulf of California, thus indicating that connectivity offered by the areas may resemble natural connectivity. The selected focal species comprise different life histories among marine or marine-related vertebrates and are associated with those habitats holding the most biodiversity values (i.e. coastal habitats); our results thus suggest that the proposed configuration may function as a network for connectivity and may adequately represent the marine megafauna in the GOC, including the potential connectivity among habitat patches. This work highlights the range of approaches that can be used to quantify habitat protection and connectivity for wide-ranging marine species in marine reserve networks.
4. Influences of the human footprint on sagebrush landscape patterns: Implications for sage-grouse conservation
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Leu, Matthias; Hanser, Steven E.; Knick, Steven T.; Connelly, John W.
2011-01-01
Spatial patterns influence the processes that maintain Greater Sage-Grouse (Centrocercus urophasianus) populations and sagebrush (Artemisia spp.) landscapes on which they depend. We used connectivity analyses to: (1) delineate the dominant pattern of sagebrush landscapes; (2) identify regions of the current range-wide distribution of Greater Sage-Grouse important for conservation; (3) estimate distance thresholds that potentially isolate populations; and (4) understand how landscape pattern, environmental disturbance, or location within the spatial network influenced lek persistence during a population decline. Long-term viability of sagebrush, assessed from its dominance in relatively unfragmented landscapes, likely is greatest in south-central Oregon and northwest Nevada; the Owyhee region of southeast Oregon, southwest Idaho, and northern Nevada; southwest Wyoming; and south-central Wyoming. The most important leks (breeding locations) for maintaining connectivity, characterized by higher counts of sage-grouse and connections with other leks, were within the core regions of the sage-grouse range. Sage-grouse populations presently have the highest levels of connectivity in the Wyoming Basin and lowest in the Columbia Basin Sage-Grouse management zones (SMZs). Leks separated by distances 1318 km could be isolated due to decreased probability of dispersals from neighboring leks. The range-wide distribution of sage-grouse was clustered into 209 separate components (units in which leks were interconnected within but not among) when dispersal was limited to distances 18 km. The most important components for maintaining connectivity were distributed across the central and eastern regions of the range-wide distribution. Connectivity among sage-grouse populations was lost during population declines from 1965 1979 to 1998 2007, most dramatically in the Columbia Basin SMZ. Leks that persisted during this period were larger in size, were more highly connected, and had lower
5. Genetic structure and seed germination in Portuguese populations of Cheirolophus uliginosus (Asteraceae: Implications for conservation strategies
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Vitales, D.
2013-12-01
Full Text Available Cheirolophus uliginosus is a threatened species, endemic to the Atlantic coast of the Iberian Peninsula, where it occupies a few restricted localities. In our study we analysed the patterns of cpDNA haplotypes variation and reproductive success—germinability—among seven Portuguese populations of varying size. The aim was to examine the reproductive performance of Ch. uliginosus related to genetic structure and population size. The results showed very low within-population variability of cpDNA markers. Our study indicates that the germination rate is significantly reduced in small populations ( 250 individuals do not show any constraint. In the search for plausible causes explaining the lower germination success in the smallest populations, ecological concerns and genetic isolation must be taken into account. Besides, in large-sized populations of Ch. uliginosus (> 250 plants a higher incidence of predispersal seed predation was observed, maybe affecting their sexual reproductive response. Finally, smaller populations—presenting a reduced reproductive success—contain also the most evolutionary distant haplotypes, so their conservation should be a priority.Cheirolophus uliginosus es una especie amenazada endémica de la costa atlántica de la península ibérica, donde ocupa unas pocas y reducidas localidades. En nuestro estudio, analizamos los patrones de variación de los haplotipos de ADN cloroplástico y el éxito reproductivo —capacidad germinativa— en siete poblaciones portuguesas de diferente tamaño. El éxito reproductivo de Ch. uliginosus se ha examinado en relación con la estructura genética y el tamaño de sus poblaciones. Los resultados indican una variabilidad intrapoblacional muy baja para los marcadores cloroplásticos utilizados. Nuestro estudio muestra una tasa de germinación significativamente reducida en las poblaciones pequeñas ( 250 individuos. Para explicar este fenómeno, se deben tomar en consideración las
6. Mapping the world's cities: An examination of global urban maps and their implications for conservation planning
Science.gov (United States)
Potere, David
derived from lower-growth, more compact futures. Our findings highlight the need to account for demographic pressure and urban planning when designing sustainable conservation strategies in the context of a rapidly urbanizing world.
7. Modeling elk and bison carrying capacity for Great Sand Dunes National Park, Baca National Wildlife Refuge, and The Nature Conservancy's Medano Ranch, Colorado
Science.gov (United States)
Wockner, Gary; Boone, Randall; Schoenecker, Kathryn A.; Zeigenfuss, Linda C.
2015-01-01
Great Sand Dunes National Park and Preserve and the neighboring Baca National Wildlife Refuge constitute an extraordinary setting that offers a variety of opportunities for outdoor recreation and natural resource preservation in the San Luis Valley of Colorado. Adjacent to these federal lands, the Nature Conservancy (TNC) manages the historic Medano Ranch. The total land area of these three conservation properties is roughly 121,500 hectares (ha). It is a remote and rugged area in which resource managers must balance the protection of natural resources with recreation and neighboring land uses. The management of wild ungulates in this setting presents challenges, as wild ungulates move freely across public and private landscapes.
8. Regulating edible insects: the challenge of adressing food security, nature conservation, and the erosion of traditional food culture
DEFF Research Database (Denmark)
Halloran, Afton Marina Szasz; Vantomme, Paul; Hanboonsong, Y.
2015-01-01
and the roles they play are discussed. Insects have only recently entered into the sustainable food dialogue, but have not yet been incorporated into policy documents and have been largely omitted from regulatory frameworks. Moreover, even in nations where there is a tradition of consuming a variety of insect...... species, they do not appear explicitly in dietary guidelines. Although food safety is a major concern, it can undermine the importance of nature conservation, traditional food culture, food security, and potential economic development. Thus, entomophagy should be viewed holistically and development......Entomophagy is a common practice in many regions of the world but there are few examples of national regulations that govern insects for human consumption. Where entomophagy is not common, the current regulatory discourse focuses primarily on food safety and consumer protection. In countries where...
9. Vascular plants diversity of El Aribabi Conservation Ranch: A private natural protected area in northern Sonora, Mexico
Science.gov (United States)
J. Jesus Sanchez-Escalante; Denise Z. Avila-Jimenez; David A. Delgado-Zamora; Liliana Armenta-Cota; Thomas R. Van Devender; Ana Lilia. Reina-Guerrero
2013-01-01
In northeastern Sonora, isolated Sky Island mountain ranges with desertscrub, desert grassland, oak woodland, and pine-oak forest have high biodiversity. El Aribabi Conservation Ranch in the Sierra Azul (from 30°51â13âN, 110°41â9âW to 30°46â38âN, 110°32â3âW) was designated a Private Protected Natural Area by the Comisión Nacional de Ãreas Naturales Protegidas in March...
10. Sexual segregation in juvenile New Zealand sea lion foraging ranges: implications for intraspecific competition, population dynamics and conservation.
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Elaine S Leung
Full Text Available Sexual segregation (sex differences in spatial organisation and resource use is observed in a large range of taxa. Investigating causes for sexual segregation is vital for understanding population dynamics and has important conservation implications, as sex differences in foraging ecology may affect vulnerability to area-specific human activities. Although behavioural ecologists have proposed numerous hypotheses for this phenomenon, the underlying causes of sexual segregation are poorly understood. We examined the size-dimorphism and niche divergence hypotheses as potential explanations for sexual segregation in the New Zealand (NZ sea lion (Phocarctos hookeri, a nationally critical, declining species impacted by trawl fisheries. We used satellite telemetry and linear mixed effects models to investigate sex differences in the foraging ranges of juvenile NZ sea lions. Male trip distances and durations were almost twice as long as female trips, with males foraging over the Auckland Island shelf and in further locations than females. Sex was the most important variable in trip distance, maximum distance travelled from study site, foraging cycle duration and percent time at sea whereas mass and age had small effects on these characteristics. Our findings support the predictions of the niche divergence hypothesis, which suggests that sexual segregation acts to decrease intraspecific resource competition. As a consequence of sexual segregation in foraging ranges, female foraging grounds had proportionally double the overlap with fisheries operations than males. This distribution exposes female juvenile NZ sea lions to a greater risk of resource competition and bycatch from fisheries than males, which can result in higher female mortality. Such sex-biased mortality could impact population dynamics, because female population decline can lead to decreased population fecundity. Thus, effective conservation and management strategies must take into account
11. Cooperative and Noncooperative Strategies for Small-scale Fisheries' Self-governance in the Globalization Era: Implications for Conservation
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Xavier Basurto
2013-12-01
Full Text Available Fishing cooperatives (co-ops and patron-client relationships are the most common cooperative and noncooperative strategies for self-governance for small-scale fisheries around the world. We studied what drives fishers to choose between these two self-governance arrangements in 12 communities in the Gulf of California, Mexico. The communities depend on similar fishing resources, are located in contiguous portions of the coast, fish roughly the same species, have similar socioeconomic characteristics, and sell to similar markets, yet half of the fisheries are organized around co-ops and the other half work through patron-client arrangements. Using participant observation, in-depth interviews of key informants between 1995-2008, and a survey of 55% of the fisheries in the study area, we found that the presence of high transaction costs of commercialization, the desire to acquire fishing licenses, and the existence of traditions of successful collective action among fishing groups within each community strongly influence fishers' choices regarding membership in fishing co-ops. We also examined the implications of our findings for conservation of fishing resources. Given that the emergence of co-ops was associated with high transaction costs of commercialization, we hypothesize that cooperative strategies are more likely than patron-client strategies to emerge in communities in isolated locations. In an era of globalization, in which the rate of development and urbanization will increase in coastal areas, patron-client strategies are likely to become more prevalent among fisheries, but such self-governance strategies are thought to be less conducive to conservation behaviors.
12. Tracing the origin of functional and conserved domains in the human proteome: implications for protein evolution at the modular level.
Science.gov (United States)
Pal, Lipika R; Guda, Chittibabu
2006-11-07
The functional repertoire of the human proteome is an incremental collection of functions accomplished by protein domains evolved along the Homo sapiens lineage. Therefore, knowledge on the origin of these functionalities provides a better understanding of the domain and protein evolution in human. The lack of proper comprehension about such origin has impelled us to study the evolutionary origin of human proteome in a unique way as detailed in this study. This study reports a unique approach for understanding the evolution of human proteome by tracing the origin of its constituting domains hierarchically, along the Homo sapiens lineage. The uniqueness of this method lies in subtractive searching of functional and conserved domains in the human proteome resulting in higher efficiency of detecting their origins. From these analyses the nature of protein evolution and trends in domain evolution can be observed in the context of the entire human proteome data. The method adopted here also helps delineate the degree of divergence of functional families occurred during the course of evolution. This approach to trace the evolutionary origin of functional domains in the human proteome facilitates better understanding of their functional versatility as well as provides insights into the functionality of hypothetical proteins present in the human proteome. This work elucidates the origin of functional and conserved domains in human proteins, their distribution along the Homo sapiens lineage, occurrence frequency of different domain combinations and proteome-wide patterns of their distribution, providing insights into the evolutionary solution to the increased complexity of the human proteome.
13. The Natural History and Conservation of Indian Ocean Humpback Dolphins (Sousa plumbea) in South African Waters.
Science.gov (United States)
Plön, Stephanie; Cockcroft, Victor G; Froneman, William P
2015-01-01
Although most knowledge on the biology of Sousa plumbea has primarily come from South African waters, a number of research gaps remain on the natural history and status of the species in the region. Research on two populations in South African waters for which some historical data exist may aid in highlighting long-term changes in the biology and natural history of this little known coastal delphinid. Recent studies on the age, growth and reproduction of animals incidentally caught in shark nets in Richards Bay, KwaZulu-Natal, yielded a lower maximum age estimate of 24 (previously 46) growth-layer-groups (GLGs), sexual maturity of 7.5 and 8 GLGs in males and females (previously 12-13 and 10 GLGs, respectively), an ovulation rate of 0.2 and a 5-year calving interval (previously 0.3 and 3-year calving interval) than previously reported. These differences may be due to a difference in the interpretation of GLGs between observers or a predominance of young males being caught in the shark nets. Stomach content analysis revealed a change in the relative proportions of the main prey items over the past 25 years, but no difference in species richness or diversity was found between the sexes. No change in trophic level was recorded between 1972 and 2009. Field studies in Algoa Bay, Eastern Cape, conducted 16 years apart indicated a decline in the mean group size (from 7 to 3 animals), a decline in the maximum group size (from 24 to 13 animals), an increase in solitary individuals (15.4-36%), and a change in behaviour from predominantly foraging (64-18%) to mainly travelling (24-49%). The observed changes are suggestive of a change in food availability, resulting in a range shift or a potential decline in numbers. These studies indicate the importance of long-term studies to monitor population changes and their possible causes. A number of threats, such as shark nets, pollution (noise and chemical), and coastal development and disturbance, to the humpback dolphin populations
14. Species diversity and conservation of orchids in Nanling National Nature Reserve, Guangdong
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Huaizhen Tian
2013-03-01
Full Text Available All known wild species of Orchidaceae are listed in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES. However, species diversity of orchids in Nanling National Nature Reserve, China, is not well known. Based on field work, inspection of herbarium specimens, and previous records, 121 species in 49 genera of Orchidaceae are listed for the reserve. Of these, 75 species are terrestrial, 40 are epiphytic and 6 are saprophytic. Species fall mainly within genera such as Bulbophyllum (10 species, Calanthe (10 species, Goodyera (10 species, Liparis (8 species, Habenaria (7 species and Cymbidum (6 species. A few species are widespread showing great abundance in the reserve, but most are rather rare having narrow distributions. Tropical type genera tend to dominate, although temperate orchids are more common at the species level. This indicates that the orchid flora is rather complex, being amix of tropic Asian types and East Asian types, particularly of Sino-Japan kind. Thus the orchid flora of Nanling N. N. R has an obvious subtropical character, with affinities to that of Taiwan. We appeal for reasonable plan on establishing power stations and related rule of law should be found to control the illegal trade of the wild orchids in Nanling N. N. R.
15. Higgs boson couplings in multi-doublet models with natural flavour conservation
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Kei Yagyu
2016-12-01
Full Text Available We investigate the deviation in the couplings of the standard model (SM like Higgs boson (h with a mass of 125 GeV from the prediction of the SM in multi-doublet models within the framework where flavour changing neutral currents at the tree level are naturally forbidden. After we present the general expressions for the modified gauge and Yukawa couplings for h, we show the correlation between the deviation in the Yukawa coupling for the tau lepton hτ+τ− and that for the bottom quark hbb¯ under the assumption of a non-zero deviation in the hVV (V=W,Z couplings in two Higgs doublet models (2HDMs and three Higgs doublet models (3HDMs as simple examples. We clarify the possible allowed prediction of the deviations in the 3HDMs which cannot be explained in the 2HDMs even taking into account the one-loop electroweak corrections to the Yukawa coupling.
16. Higgs boson couplings in multi-doublet models with natural flavour conservation
CERN Document Server
Yagyu, Kei
2016-01-01
We investigate the deviation in couplings of the standard model (SM) like Higgs boson ($h$) with the mass of 125 GeV from the prediction of the SM in multi-doublet models within the framework where flavour changing neutral currents at the tree level are naturally forbidden. After we present the general expressions for the modified gauge and Yukawa couplings for $h$, we show the correlation between the deviation in the Yukawa coupling for the tau lepton $h\\tau^+\\tau^-$ and that for the bottom quark $hb\\bar{b}$ under the assumption of a non-zero deviation in the $hVV$ $(V=W,Z)$ couplings in two Higgs doublet models (2HDMs) and three Higgs doublet models (3HDMs) as the simple examples. We clarify the possible allowed prediction of the deviations in the 3HDMs which cannot be explained in the 2HDMs even taking into account the one-loop electroweak corrections to the Yukawa coupling.
17. New Methods in Acquisition, Update and Dissemination of Nature Conservation Geodata - Implementation of an Integrated Framework
Science.gov (United States)
Tintrup gen. Suntrup, G.; Jalke, T.; Streib, L.; Keck, N.; Nieland, S.; Moran, N.; Kleinschmit, B.; Trapp, M.
2015-04-01
Within the framework of this project methods are being tested and implemented a) to introduce remote sensing based approaches into the existing process of biotope mapping and b) to develop a framework serving the multiple requirements arising from different users' backgrounds and thus the need for comprehensive data interoperability. Therefore state-wide high resolution land cover vector-data have been generated in an automated object oriented workflow based on aerial imagery and a normalised digital surface models.These data have been enriched by an extensive characterisation of the individual objects by e.g. site specific, contextual or spectral parameters utilising multitemporal satellite images, DEM-derivatives and multiple relevant geo-data. Parameters are tested on relevance in regard to the classification process using different data mining approaches and have been used to formalise categories of the European nature information system (EUNIS) in a semantic framework. The Classification will be realised by ontology-based reasoning. Dissemination and storage of data is developed fully INSPIRE-compatible and facilitated via a web portal. Main objectives of the project are a) maximum exploitation of existing "standard" data provided by state authorities, b) combination of these data with satellite imagery (Copernicus), c) create land cover objects and achieve data interoperability through low number of classes but comprehensive characterisation and d) implement algorithms and methods suitable for automated processing on large scales.
18. Allozyme variation and structure of the Canarian endemic palm tree Phoenix canariensis (Arecaceae): implications for conservation.
Science.gov (United States)
González-Pérez, M A; Caujapé-Castells, J; Sosa, P A
2004-09-01
Electrophoretic analysis of 18 allozyme loci was used to estimate the levels and structuring of genetic variation within and among natural populations of the protected endemic palm species from the Canary Islands (Phoenix canariensis) to evaluate its genetic relationship with the widespread congener P. dactylifera, and to assess comparatively the genetic variation in the populations where the two species coexist with morphologically intermediate plants (mixed populations). Our survey revealed that the within-population component explains roughly 75% of the genetic variation levels detected in P. canariensis (A=1.59; P=41.8; He=0.158), which rank higher than those reported for other species of the Arecaceae. A Principal Component analysis (PCA) based on allele frequencies consistently separates populations of P. canariensis and P. dactylifera, and reveals a close genetic relationship between P. canariensis and the mixed populations. Reduced levels of genetic variation in P. canariensis with respect to P. dactylifera, the fact that the genetic makeup of the Canarian endemic (with no unique alleles) is a subset of that found in P. dactylifera, and the high genetic identity between both species strongly suggest that P. canariensis is recently derived from a common ancestor closely related to P. dactylifera.
19. Multiple injected and natural conservative tracers quantify mixing in a stream confluence affected by acid mine drainage near Silverton, Colorado
Science.gov (United States)
Schemel, L.E.; Cox, M.H.; Runkel, R.L.; Kimball, B.A.
2006-01-01
The acidic discharge from Cement Creek, containing elevated concentrations of dissolved metals and sulphate, mixed with the circumneutral-pH Animas River over a several hundred metre reach (mixing zone) near Silverton, CO, during this study. Differences in concentrations of Ca, Mg, Si, Sr, and SO42- between the creek and the river were sufficiently large for these analytes to be used as natural tracers in the mixing zone. In addition, a sodium chloride (NaCl) tracer was injected into Cement Creek, which provided a Cl- 'reference' tracer in the mixing zone. Conservative transport of the dissolved metals and sulphate through the mixing zone was verified by mass balances and by linear mixing plots relative to the injected reference tracer. At each of seven sites in the mixing zone, five samples were collected at evenly spaced increments of the observed across-channel gradients, as determined by specific conductance. This created sets of samples that adequately covered the ranges of mixtures (mixing ratios, in terms of the fraction of Animas River water, %AR). Concentrations measured in each mixing zone sample and in the upstream Animas River and Cement Creek were used to compute %AR for the reference and natural tracers. Values of %AR from natural tracers generally showed good agreement with values from the reference tracer, but variability in discharge and end-member concentrations and analytical errors contributed to unexpected outlier values for both injected and natural tracers. The median value (MV) %AR (calculated from all of the tracers) reduced scatter in the mixing plots for the dissolved metals, indicating that the MV estimate reduced the effects of various potential errors that could affect any tracer.
20. Multiple injected and natural conservative tracers quantify mixing in a stream confluence affected by acid mine drainage near Silverton, Colorado
Science.gov (United States)
Schemel, Laurence E.; Cox, Marisa H.; Runkel, Robert L.; Kimball, Briant A.
2006-08-01
The acidic discharge from Cement Creek, containing elevated concentrations of dissolved metals and sulphate, mixed with the circumneutral-pH Animas River over a several hundred metre reach (mixing zone) near Silverton, CO, during this study. Differences in concentrations of Ca, Mg, Si, Sr, and SO42- between the creek and the river were sufficiently large for these analytes to be used as natural tracers in the mixing zone. In addition, a sodium chloride (NaCl) tracer was injected into Cement Creek, which provided a Cl- reference tracer in the mixing zone. Conservative transport of the dissolved metals and sulphate through the mixing zone was verified by mass balances and by linear mixing plots relative to the injected reference tracer. At each of seven sites in the mixing zone, five samples were collected at evenly spaced increments of the observed across-channel gradients, as determined by specific conductance. This created sets of samples that adequately covered the ranges of mixtures (mixing ratios, in terms of the fraction of Animas River water, %AR). Concentratis measured in each mixing zone sample and in the upstream Animas River and Cement Creek were used to compute %AR for the reference and natural tracers. Values of %AR from natural tracers generally showed good agreement with values from the reference tracer, but variability in discharge and end-member concentrations and analytical errors contributed to unexpected outlier values for both injected and natural tracers. The median value (MV) %AR (calculated from all of the tracers) reduced scatter in the mixing plots for the dissolved metals, indicating that the MV estimate reduced the effects of various potential errors that could affect any tracer.
1. Challenges of transfrontier conservation areas: Natural resources nationalism, security and regionalism in the southern African development community region
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Oswell Rusinga
2012-12-01
Full Text Available Transfrontier Conservation Areas (TFCAs initiatives in the Southern African Development Community (SADC region offer hope for providing a mechanism for resolving political tensions and conflicts which are not only related to environmental issues but to security concerns as well. The geopolitical implications of TFCAs in the SADC region cannot be overemphasised with regard to international relations and regional integration. The SADS region is characterised by histories of contested military balance of power and geopolitical rivalries which have a potential to degenerate into military confrontation. Although there is a strong belief in multilateral co-operation among SADC member countries, most of them often engage the international community at the bilateral level. Moreover, there is disharmony in constitutional applications of the rule of law, respect of human rights and good governance. However, TFCAs initiatives in Southern Africa have been seen as offering an opportunity to heal the wounds of pre- and post-independence wars of destabilisation through the encouragement of inter-state collaboration and co-operation by giving governments an opportunity for mutual action on issues of common interest.
2. SEX DETERMINATION IN INDONESIAN PUFFERFISH Tetraodon palembangensis Bleeker, 1852: IMPLICATION FOR AQUACULTURE AND CONSERVATION
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Media Fitri Isma Nugraha
2011-06-01
Full Text Available The study was based on eight specimens from a single population of Palembang pufferfish. We used a comprehensive approach comprise behavioral record, the Random Amplified Polymorphism DNA technique, exteriorly genital observation and the description of morphological coloration distinctive to recognize gender. Annotation from captivity has yielded that two genders in couple were possessed the prominent social respond in shoaling-fidelity. When the gonadal process has been released by maternal part, eggs and offspring were kept by male and there is no tolerable contact of female were given, here the female has become more cannibalism. Male adult has more brown-blackish and occasionally more flukes-dark on the half upper horizontal body it has less towering bulk and only has one genitalial hole. Female furthermore is recognizable with the present hight-bulk and has more yellow overall flukes in coloration and widely bright yellowish-dark from abdomental part to the edge of middle half of the body. Contrary, female has two genitalian holes. RAPD also has confirmed a concordance linkage what we are previously expected. We found an important mutation 176 bp for both gender. Among the scaffold obtained, scaffold 33 is a common scaffold identified within T. palembangensis and Takifugu, it has a sufficient score bit of 36.2 with a length of nucleotide 1,758,880 bp. Moreover, this scaffold is the result from primer OPP-19 in the female of T. palembangensis, we thus can finally distinguish their sex status. The scaffold 33 might relate to the gene SOX. Our attempt may hatch a new horizon for institutional developers, aquarist and conservationist in case of surety for sustainable natural population and to ensure their stock for consumption and trading ornament requirement.
3. Rethinking the Galapagos Islands as a Complex Social-Ecological System: Implications for Conservation and Management
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José A. González
2008-12-01
Full Text Available The Galapagos Islands are among the most renowned natural sites in the world. Unlike other oceanic archipelagos, the ecological and evolutionary processes characteristic of Galapagos have been minimally affected by human activities, and the archipelago still retains most of its original, unique biodiversity. However, several recent reports suggest that the development model has turned unsustainable and that the unique values of the archipelago might be seriously at risk. In response to international concern, UNESCO added Galapagos to the list of World Heritage in Danger in 2007. Our goal was to provide new insights into the origins of the present-day crisis and suggest possible management alternatives. To this end, we re-examined the Galapagos situation from a broad systems perspective, conceptualizing the archipelago as a complex social-ecological system. Past, present, and possible future trends were explored using the resilience theory as a perspective for understanding the dynamics of the system. Four major historical periods were characterized and analyzed using Holling's adaptive cycle metaphor. The current Galapagos situation was characterized as a prolonged series of crisis events followed by renewal attempts that have not yet been completed. Three plausible future scenarios were identified, with tourism acting as the primary driver of change. The current tourism model reduces the system's resilience through its effects on the economy, population growth, resource consumption, invasive species arrival, and lifestyle of the island residents. Opportunities to reorganize and maintain a desirable state do exist. However, strong political and management decisions are urgently needed to avoid an irreversible shift to a socially and environmentally undesirable regime. Key measures to achieve a new sustainability paradigm for Galapagos include modifying traditional practices to produce a more adaptive resilience-based co-management model
4. Anti-amyloid Aggregation Activity of Natural Compounds: Implications for Alzheimer's Drug Discovery.
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Bu, Xian-Le; Rao, Praveen P N; Wang, Yan-Jiang
2016-08-01
Several plant-derived natural compounds are known to exhibit anti-amyloid aggregation activity which makes them attractive as potential therapies to treat Alzheimer's disease. The mechanisms of their anti-amyloid activity are not well known. In this regard, many natural compounds are known to exhibit direct binding to various amyloid species including oligomers and fibrils, which in turn can lead to conformational change in the beta-sheet assembly to form nontoxic aggregates. This review discusses the mechanism of anti-amyloid activity of 16 natural compounds and gives structural details on their direct binding interactions with amyloid aggregates. Our computational investigations show that the physicochemical properties of natural products do fit Lipinski's criteria and that catechol and catechol-type moieties present in natural compounds act as lysine site-specific inhibitors of amyloid aggregation. Based on these observations, we propose a structural template to design novel small molecules containing site-specific ring scaffolds, planar aromatic and nonaromatic linkers with suitably substituted hydrogen bond acceptors and donors. These studies will have significant implications in the design and development of novel amyloid aggregation inhibitors with superior metabolic stability and blood-brain barrier penetration as potential agents to treat Alzheimer's disease.
5. Historia and materia: the philosophical implications of Francis Bacon's natural history.
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Giglioni, Guido
2012-01-01
This article examines the philosophical implications underlying Bacon's views on historical knowledge, paying special attention to that variety of historical knowledge described by Bacon as "natural." More specifically, this article explores the interplay of history (historia) and fable (fabula). In the sphere of thought, fabula is the equivalent to materia in nature. Both are described by Bacon as being "versatile" and "pliant." In Bacon's system of knowledge, philosophy, as the domain of reason, starts from historiae and fabulae, once memory and the imagination have fulfilled their cognitive tasks. This means that, for Bacon, there is no such thing as a pure use of reason. He advocates a kind of reason that, precisely because it is involved with matter's inner motions (its "appetites," in Bacon's characteristic language), is constitutively 'impure'. The article shows how the terms historia and fabula cover key semantic areas in defining Bacon's philosophy: historia may mean "history" as well as "story,"fabula "myth" as well "story". In both cases, we can see significant oscillations from a stronger meaning (close to those of matter and nature) to a weaker one (connected to wit and imagination), as if the power of nature decreases moving from histories and myths to stories. On the other hand, there are cases in which Bacon seems to stick to a diachronic view of the meaning of fables and histories, such that the transition from myths to history, especially natural history, is described as a collective effort towards reality and enlightenment.
6. Fire patterns in the range of the greater sage-grouse, 1984-2013 — Implications for conservation and management
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Brooks, Matthew L.; Matchett, John R.; Shinneman, Douglas J.; Coates, Peter S.
2015-09-10
Fire ranks among the top three threats to the greater sage-grouse (Centrocercus urophasianus) throughout its range, and among the top two threats in the western part of its range. The national research strategy for this species and the recent U.S. Department of the Interior Secretarial Order 3336 call for science-based threats assessment of fire to inform conservation planning and fire management efforts. The cornerstone of such assessments is a clear understanding of where fires are occurring and what aspects of fire regimes may be shifting outside of their historical range of variation. This report fulfills this need by describing patterns of fire area, fire size, fire rotation, and fire season length and timing from 1984 to 2013 across the range of the greater sage-grouse. This information need is further addressed by evaluating the ecological and management implications of these fire patterns. Analyses are stratified by major vegetation types and the seven greater sage-grouse management zones, delineated regionally as four western and three eastern management zones. Soil temperature and moisture indicators of resilience to fire and resistance to cheatgrass invasion, and the potential for establishment of a grass/fire cycle, are used as unifying concepts in developing fire threat assessments for each analysis strata.
7. Reproductive biology of Ilisha elongata (Teleostei: Pristigasteridae) in Ariake Sound, Japan: Implications for estuarine fish conservation in Asia
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Zhang, Jie; Takita, Toru; Zhang, Chunguang
2009-01-01
Elongate ilisha ( Ilisha enlongata) is a commercially important species that contributes to clupeoid fisheries in Asian countries. In the present study, the reproductive biology of I. elongata in Ariake Sound, Japan is determined for the first time. Six maturity stages were described using ovarian and testicular histology throughout the annual cycle. The spawning season in Ariake Sound lasts from May to July, with peak spawning activity in May and June. Age at first maturity was estimated to be 2 years, with a few exceptions of 1 year in well-developed males. Ovaries that contained both tertiary yolk oocytes and postovulatory follicles occurred from late May to late July, indicating that I. elongata is a multiple spawner. The size-frequency distribution of oocytes provided evidence for its multiple spawning and accuracy of the fecundity estimates. The batch fecundity of this species was estimated at between 22,200 and 270,900 eggs per individual, increasing with age between two and six years. The present findings on the reproductive strategy of I. elongata in Ariake Sound are generally consistent with those in temperate or subtropical populations, but quite different from those of tropical population where first maturation occurs around 200 days and life spans are shorter, with a maximum age less than 3 years. The conservation implications of this reproductive strategy in a harsh, variable environment in Asian countries are also discussed.
8. Effects of supplementing Leucaena leucocephala and conserved forages from natural pasture on the performance of grazing calves.
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Ojo, Victoria Olubunmi A; Aina, Ayobami B J; Fasae, Oladapo A; Oni, Adebayo O; Aderinboye, Ronke Y; Dele, Peter A; Idowu, Oluwaseun J; Adelusi, Oludotun O; Shittu, Olalekan O; Okeniyi, Funmilayo A; Jolaosho, Alaba O
2014-01-01
Twelve white Fulani × N'dama cross-bred calves weighing 83.79 ± 1.16 kg were used in an 84-day experiment to investigate the utilization of forage resources from natural grazing land. The experimental diets were sole grazing, grazing + hay, grazing + silage and grazing + Leucaena leucocephala leaves. The calves were divided into four groups of three animals each and were randomly assigned to the four experimental diets. Crude protein (CP) contents of the forages ranged from 59 to 171 g/kg dry matter (DM). Neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents of the forages ranged from 560 to 705 g/kg DM and 363 to 440 g/kg DM, respectively. Significantly (P < 0.05) higher values in mineral contents (Ca, K, P and Mg) were recorded for L. leucocephala leaves compared to other forage resources. Variations (P < 0.05) were observed in the average daily gain. Animals on grazing + L. leucocephala leaves diet had the highest (113 g/day) average daily gain, while those on sole grazing showed the least value (26.2 g/day). Packed cell volume (PCV), total serum protein, urea and calcium concentration showed significant differences (P < 0.05). Effective utilization of forage resources from the natural pasture by the calves was attained on supplementation with conserved forages and L. leucocephala leaves without any deleterious effects on the haematological and serum parameters.
9. Saving Our Planet's Flora, the Contribution of the French National Natural History Museum to the Implementation of the Global Strategy for Plant Conservation
Institute of Scientific and Technical Information of China (English)
Ma(i)té DELMAS; Jean-Patrick LE DUC
2011-01-01
The National Natural History Museum plays a key role in the implementation of the GSPC through its botanical gardens, the Conservatoire Botanique National du Bassin Parisien, the Herbarium, and also by providing expertise on all areas of the Strategy (botany, conservation, ethonobotany, article 8j, substainable use), etc. For 2 of developed activities all over the world, including compilation of various flora and description of new species, as well as establishment of plant conservation schemes and habitat protection policies. It also conserves endangered species in the botanical garden.
10. Depression and suicide are natural kinds: implications for physician-assisted suicide.
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Tsou, Jonathan Y
2013-01-01
In this article, I argue that depression and suicide are natural kinds insofar as they are classes of abnormal behavior underwritten by sets of stable biological mechanisms. In particular, depression and suicide are neurobiological kinds characterized by disturbances in serotonin functioning that affect various brain areas (i.e., the amygdala, anterior cingulate, prefrontal cortex, and hippocampus). The significance of this argument is that the natural (biological) basis of depression and suicide allows for reliable projectable inferences (i.e., predictions) to be made about individual members of a kind. In the context of assisted suicide, inferences about the decision-making capacity of depressed individuals seeking physician-assisted suicide are of special interest. I examine evidence that depression can hamper the decision-making capacity of individuals seeking assisted suicide and discuss some implications.
11. College biology students' conceptions related to the nature of biological knowledge: Implications for conceptual change
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Ameny, Gloria Millie Apio
Adequate understanding of the nature of science is a major goal of science education. Understanding of the evolutionary nature of biological knowledge is a means of reinforcing biology students' understanding of the nature of science. It provides students with the philosophical basis, explanatory ideals, and subject matter-specific views of what counts as a scientifically-acceptable biological explanation. This study examined 121 college introductory biology and advanced zoology students for their conceptions related to the nature of biological knowledge. A 60-item Likert-scale questionnaire called the Nature of Biological Knowledge Scale and student interviews were used as complementary research instruments. Firstly, the study showed that 80--100% of college biology students have an adequate understanding of scientific methods, and that a similar percentage of students had learned the theory of evolution by natural selection in their biology courses. Secondly, the study showed that at least 60--80% of the students do not understand the importance of evolution in biological knowledge. Yet the study revealed that a statistically significant positive correlation exist among students' understanding of natural selection, divergent, and convergent evolutionary models. Thirdly, the study showed that about 20--58% of college students hold prescientific conceptions which, in part, are responsible for students' lack of understanding of the nature of biological knowledge. A statistically significant negative correlation was found among students' prescientific conceptions about basis of biological knowledge and nature of change in biological processes, and their understanding of natural selection and evolutionary models. However, the study showed that students' characteristics such as gender, age, major, or years in college have no statistically significant influence on students' conceptions related to the nature of biological knowledge. Only students' depth of biological
12. Trade-offs for food production, nature conservation and climate limit the terrestrial carbon dioxide removal potential.
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Boysen, Lena R; Lucht, Wolfgang; Gerten, Dieter
2017-10-01
Large-scale biomass plantations (BPs) are a common factor in climate mitigation scenarios as they promise double benefits: extracting carbon from the atmosphere and providing a renewable energy source. However, their terrestrial carbon dioxide removal (tCDR) potentials depend on important factors such as land availability, efficiency of capturing biomass-derived carbon and the timing of operation. Land availability is restricted by the demands of future food production depending on yield increases and population growth, by requirements for nature conservation and, with respect to climate mitigation, avoiding unfavourable albedo changes. We integrate these factors in one spatially explicit biogeochemical simulation framework to explore the tCDR opportunity space on land available after these constraints are taken into account, starting either in 2020 or 2050, and lasting until 2100. We find that assumed future needs for nature protection and food production strongly limit tCDR potentials. BPs on abandoned crop and pasture areas (~1,300 Mha in scenarios of either 8.0 billion people and yield gap reductions of 25% until 2020 or 9.5 billion people and yield gap reductions of 50% until 2050) could, theoretically, sequester ~100 GtC in land carbon stocks and biomass harvest by 2100. However, this potential would be ~80% lower if only cropland was available or ~50% lower if albedo decreases were considered as a factor restricting land availability. Converting instead natural forest, shrubland or grassland into BPs could result in much larger tCDR potentials ̶ but at high environmental costs (e.g. biodiversity loss). The most promising avenue for effective tCDR seems to be improvement of efficient carbon utilization pathways, changes in dietary trends or the restoration of marginal lands for the implementation of tCDR. © 2017 John Wiley & Sons Ltd.
13. The Effectiveness of Conservation Reserves: Land Tenure Impacts upon Biodiversity across Extensive Natural Landscapes in the Tropical Savannahs of the Northern Territory, Australia
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John C.Z. Woinarski
2013-01-01
Full Text Available This study examines whether there is a biodiversity benefit (“dividend” associated with the existence and management of conservation reserves in the extensive and largely natural landscape of northern Australia. Species richness and abundance of vertebrate fauna and the intensity of a range of disturbance factors were compared across a set of 967 sampled quadrats, located either in pastoral lands, Indigenous lands or conservation reserves, with all sampled quadrats within a single vegetation type (open forests and savannah woodlands dominated by Eucalyptus miniata and/or E. tetrodonta. The relationships with land tenure varied between major taxonomic groups, but generally (and particularly for threatened species values were highest for conservation reserves. This “biodiversity dividend” associated with conservation reserves is considered to be due to the effects of management rather than because conservation reserves were established on lands supporting atypically high conservation values. The impact of weeds and (unsurprisingly livestock was greatest on pastoral lands, and pig impact was greatest in conservation reserves. Although pastoral and Indigenous lands supported lower biodiversity tallies than reserved lands, the conservation values of reserved lands in this region are probably substantially supported by the maintenance of relatively intact ecological systems across all lands.
14. Time-varying sensitivity analysis of hydrologic and sediment parameters at multiple timescales: Implications for conservation practices.
Science.gov (United States)
Xie, Hui; Shen, Zhenyao; Chen, Lei; Qiu, Jiali; Dong, Jianwei
2017-11-15
Environmental models can be used to better understand the hydrologic and sediment behavior in a watershed system. However, different processes may dominate at different time periods and timescales, which highly complicate the model interpretation. The related parameter uncertainty may be significant and needs to be addressed to avoid bias in the watershed management. In this study, we used the time-varying and multi-timescale (TVMT) method to characterize the temporal dynamics of parameter sensitivity at different timescales in hydrologic and sediment modeling. As a case study, the first order sensitivity indices were estimated with the Fourier amplitude sensitivity test (FAST) method for the Hydrological Simulation Program - Fortran (HSPF) model in the Zhangjiachong catchment in the Three Gorge Reservoir Region (TGRR) in China. The results were compared to those of the traditional aggregate method to demonstrate the merits of the TVMT method. The time-varying nature of the hydrologic and sediment parameters was revealed and explained mainly by the variation of hydro-climatic conditions. The baseflow recession parameter, evapotranspiration (ET) parameter for the soil storage, and sediment washoff parameter showed high sensitivities almost across the whole period. However, parameters related to canopy interception and channel sediment scour varied notably over time due to changes in the climate forcing. The timescale-dependent characteristics was observed and was most evident for the baseflow recession parameter and ET parameter. At last, the parameters affecting the sediment export and transport were discussed together with the inferred conservation practices. Reasonable controls for sediment must be storm-dependent. Compared to management practices on the land surface, practices affecting channel process would be more effective during storm events. Our results present one of the first investigations for sediment modeling in terms of the importance of parameter
15. Tracing the origin of functional and conserved domains in the human proteome: implications for protein evolution at the modular level
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Guda Chittibabu
2006-11-01
Full Text Available Abstract Background The functional repertoire of the human proteome is an incremental collection of functions accomplished by protein domains evolved along the Homo sapiens lineage. Therefore, knowledge on the origin of these functionalities provides a better understanding of the domain and protein evolution in human. The lack of proper comprehension about such origin has impelled us to study the evolutionary origin of human proteome in a unique way as detailed in this study. Results This study reports a unique approach for understanding the evolution of human proteome by tracing the origin of its constituting domains hierarchically, along the Homo sapiens lineage. The uniqueness of this method lies in subtractive searching of functional and conserved domains in the human proteome resulting in higher efficiency of detecting their origins. From these analyses the nature of protein evolution and trends in domain evolution can be observed in the context of the entire human proteome data. The method adopted here also helps delineate the degree of divergence of functional families occurred during the course of evolution. Conclusion This approach to trace the evolutionary origin of functional domains in the human proteome facilitates better understanding of their functional versatility as well as provides insights into the functionality of hypothetical proteins present in the human proteome. This work elucidates the origin of functional and conserved domains in human proteins, their distribution along the Homo sapiens lineage, occurrence frequency of different domain combinations and proteome-wide patterns of their distribution, providing insights into the evolutionary solution to the increased complexity of the human proteome.
16. Population Genetic Structure of the Medicinal Plant Vitex rotundifolia in China: Implications for its Use and Conservation
Institute of Scientific and Technical Information of China (English)
Yuan Hu; Yu Zhu; Qiao-Yan Zhang; Hai-Liang Xin; Lu-Ping Qin; Bao-Rong Lu; Khalid Rahman; Han-Chen Zheng
2008-01-01
Vitexrotundifolia L.is an important plant species used in traditional Chinese medicine.For its efficient use and conservation,genetic diversity and clonal variation of V.rotundifolia populations in China were investigated using inter-simple sequence repeat markers.Fourteen natural populations were included to estimate genetic diversity,and a large population with 135 individuals was used to analyze clonal variation and fine-scale spatial genetic structure.The overall genetic diversity (GD) of V.rotundifolia populations in China was moderate (GD=0.190),with about 40% within-population variation.Across all populations surveyed,the average within-population diversity was moderate (P = 22.6%; GD = 0.086).A relatively high genetic differentiation (Gst=0.587)among populations was detected based on the analysis of molecular variance data.Such characteristics of V.rotundifolia are likely attributed to its sexual/asexual reproduction and limited gene flow.The genotypic diversity (D=0.992) was greater than the average values of a clonal plant,indicating its significant reproduction through seedlings.Spatial autocorrelation analysis showed a clear within-population structure with gene clusters of approximately 20 m.Genetic diversity patterns of V.rotundifolia in China provide a useful guide for its efficient use and conservation by selecting particular populations displaying greater variation that may contain required medicinal compounds,and by sampling individuals in a population at >20 m spatial intervals to avoid collecting individuals with identical or similar genotypes.
17. The Implications of Naturalism as an Educational Philosophy in Jordan from the Perspectives of Childhood Education Teachers
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Khasawneh, Omar; Khaled, Ahmed; Al Momani, Mohammad
2016-01-01
The purpose of this study was to identify the educational implications of naturalism as an educational philosophy from the Jordanian childhood education teachers' perspectives. Each philosophy simply represents a unique conviction concerning the nature of the teaching/learning process. This study could serve as a grounded theory for Jordanian…
18. Man, nature and conservation
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D. Hey
1977-01-01
Full Text Available I am sure that it is common cause at a gathering such as this that we live in a country of remarkable scenic beauty. Consider for example, our extensive beaches of golden sands, spectacular rocky headlands, rugged mountain chains, vast Karoo's, desert landscapes, rolling grasslands, acacia studded savannas and the unique bushveld where we are gathered today.
19. A checklist of the reptiles and amphibians found in protected areas along the South African Wild Coast, with notes on conservation implications
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Jan A. Venter
2015-03-01
Full Text Available We surveyed six protected areas along the Wild Coast of the Eastern Cape, South Africa, to determine general herpetofaunal diversity as well as the representation of species of special conservation concern. Visual encounter survey methods and standard Y-shape trap arrays were used to conduct surveys from 2011 to 2013. A total of 59 species (22 amphibians and 37 reptiles were recorded. A number of previously unknown populations of threatened species and one potential novel species were discovered in these protected areas, and the known ranges of several other species were extended. A total of 243 quarter-degree grid-cell unit records were documented, of which 90 (23% amphibians and 50% reptiles represented the first records for the area. Amphibian and reptile diversity increased along the coast and a number of species of conservation concern were well represented in current protected areas. Our study provides a comprehensive amphibian and reptile checklist for an under-sampled region and highlights the importance of baseline data for improving conservation management.Conservation implications: Small protected areas play an important role in conserving a number of threatened herpetofaunal species along the Wild Coast. The region is currently under significant and increasing pressure from anthropogenic-induced environmental degradation, which affects biodiversity and subsequently the local inhabitants. The information presented here represents an important baseline for future conservation management.
20. Rapid assessment of ecosystem services provided by two mineral extraction sites restored for nature conservation in an agricultural landscape in eastern England.
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Phillip J Blaen
Full Text Available Despite growing recognition that mineral sites restored for nature conservation can enhance local biodiversity, the wider societal benefits provided by this type of restoration relative to alternative options are not well understood. This study addresses this research gap by quantifying differences in ecosystem services provision under two common mineral site after-uses: nature conservation and agriculture. Using a combination of site-specific primary field data, benefits transfer and modelling, we show that for our sites restoration for nature conservation provides a more diverse array of ecosystem services than would be delivered under an agricultural restoration scenario. We also explore the effects of addressing different conservation targets, which we find alter the provision of ecosystem services on a service-specific basis. Highly species-focused intervention areas are associated with increased carbon storage and livestock grazing provision, whereas non-intervention areas are important for carbon sequestration, fishing, recreation and flood risk mitigation. The results of this study highlight the wider societal importance of restored mineral sites and may help conservation managers and planners to develop future restoration strategies that provide benefits for both biodiversity and human well-being.
1. Securing water for wetland conservation: a comparative analysis of policy options to protect a national nature reserve in China.
Science.gov (United States)
Wu, Jian; Wu, Junjie; Wang, Xiaoxia; Zhong, Ma
2012-02-01
This study evaluates four policy options to secure the water supply needed for wetland conservation in Qixinghe--a national wetland nature reserve in China--using four criteria: cost effectiveness, probability of success in achieving the water-saving goal, political feasibility, and farmer acceptance. This multi-criteria analysis framework reveals the ecological, economic, and socio-political trade-offs for policymakers when choosing among the four policy options. Results suggest that upgrading irrigation infrastructure in the area surrounding the wetland (Option I) is the most politically feasible option, but it is the second best option in terms of cost effectiveness. Constructing a dam to store and control floodwater (Option II) is the most reliable for achieving the water-saving goal. It is also the farmers' most favored strategy. But this option is the least cost effective and receives little support from local governments. Promoting farmers' adoption of water-saving practices (Option III) is the most cost effective, but it is less reliable for achieving the water-saving goal than Options I or II. Converting paddy crops to dry-land crops (Option IV) is politically infeasible and least reliable for achieving the water-saving goal. The overall ranking of the four options is determined using the policymakers' revealed weights on the four criteria. Option I is ranked first, followed by Options II, III, and IV.
2. Biocontrol of tomato wilt disease by Bacillus subtilis isolates from natural environments depends on conserved genes mediating biofilm formation
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Liu, Hongxia; Kolter, Roberto; Losick, Richard; Guo, Jian-hua
2014-01-01
Summary Bacillus subtilis and other Bacilli have long been used as biological control agents against plant bacterial diseases but the mechanisms by which the bacteria confer protection are not well understood. Our goal in this study was to isolate strains of B. subtilis that exhibit high levels of biocontrol efficacy from natural environments and to investigate the mechanisms by which these strains confer plant protection. We screened a total of sixty isolates collected from various locations across China and obtained six strains that exhibited above 50% biocontrol efficacy on tomato plants against the plant pathogen Ralstonia solanacearum under greenhouse conditions. These wild strains were able to form robust biofilms both in defined medium and on tomato plant roots and exhibited strong antagonistic activities against various plant pathogens in plate assays. We show that plant protection by those strains depended on widely conserved genes required for biofilm formation, including regulatory genes and genes for matrix production. We provide evidence suggesting that matrix production is critical for bacterial colonization on plant root surfaces. Finally, we have established a model system for studies of B. subtilis-tomato plant interactions in protection against a plant pathogen. PMID:22934631
3. Regulation of Nav1.7: A Conserved SCN9A Natural Antisense Transcript Expressed in Dorsal Root Ganglia.
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Jennifer Koenig
Full Text Available The Nav1.7 voltage-gated sodium channel, encoded by SCN9A, is critical for human pain perception yet the transcriptional and post-transcriptional mechanisms that regulate this gene are still incompletely understood. Here, we describe a novel natural antisense transcript (NAT for SCN9A that is conserved in humans and mice. The NAT has a similar tissue expression pattern to the sense gene and is alternatively spliced within dorsal root ganglia. The human and mouse NATs exist in cis with the sense gene in a tail-to-tail orientation and both share sequences that are complementary to the terminal exon of SCN9A/Scn9a. Overexpression analyses of the human NAT in human embryonic kidney (HEK293A and human neuroblastoma (SH-SY5Y cell lines show that it can function to downregulate Nav1.7 mRNA, protein levels and currents. The NAT may play an important role in regulating human pain thresholds and is a potential candidate gene for individuals with chronic pain disorders that map to the SCN9A locus, such as Inherited Primary Erythromelalgia, Paroxysmal Extreme Pain Disorder and Painful Small Fibre Neuropathy, but who do not contain mutations in the sense gene. Our results strongly suggest the SCN9A NAT as a prime candidate for new therapies based upon augmentation of existing antisense RNAs in the treatment of chronic pain conditions in man.
4. Regulation of Nav1.7: A Conserved SCN9A Natural Antisense Transcript Expressed in Dorsal Root Ganglia.
Science.gov (United States)
Koenig, Jennifer; Werdehausen, Robert; Linley, John E; Habib, Abdella M; Vernon, Jeffrey; Lolignier, Stephane; Eijkelkamp, Niels; Zhao, Jing; Okorokov, Andrei L; Woods, C Geoffrey; Wood, John N; Cox, James J
2015-01-01
The Nav1.7 voltage-gated sodium channel, encoded by SCN9A, is critical for human pain perception yet the transcriptional and post-transcriptional mechanisms that regulate this gene are still incompletely understood. Here, we describe a novel natural antisense transcript (NAT) for SCN9A that is conserved in humans and mice. The NAT has a similar tissue expression pattern to the sense gene and is alternatively spliced within dorsal root ganglia. The human and mouse NATs exist in cis with the sense gene in a tail-to-tail orientation and both share sequences that are complementary to the terminal exon of SCN9A/Scn9a. Overexpression analyses of the human NAT in human embryonic kidney (HEK293A) and human neuroblastoma (SH-SY5Y) cell lines show that it can function to downregulate Nav1.7 mRNA, protein levels and currents. The NAT may play an important role in regulating human pain thresholds and is a potential candidate gene for individuals with chronic pain disorders that map to the SCN9A locus, such as Inherited Primary Erythromelalgia, Paroxysmal Extreme Pain Disorder and Painful Small Fibre Neuropathy, but who do not contain mutations in the sense gene. Our results strongly suggest the SCN9A NAT as a prime candidate for new therapies based upon augmentation of existing antisense RNAs in the treatment of chronic pain conditions in man.
5. Orgunity as the sum of organisation and community: An example of Ornithological Society and Nature Conservation Association
Directory of Open Access Journals (Sweden)
Dan Podjed
2014-07-01
Full Text Available The article, based on ethnographic research, highlights the dynamics of relationships in DOPPS, the Slovenian ornithological and nature conservation society, and describes a mixture of voluntary and professional activities in the organization. The article also addresses the conflicts among different groups that exist within DOPPS and describes the reciprocity, cooperation and unification of the cultural assumptions which are important for achieving common goals. The author claims that unstable and conflicting relationships in the association have led to a unique combination of hierarchical organization and egalitarian community. The British social anthropologist Martin Parker names this combination “orgunity”. Though structured and organized, a social form of this kind is based on the rudimentary affiliation and solidarity of its members. The boundary between work and leisure is blurred, hierarchical relationships are not clearly defined, members contribute equally to the production of the group and to various activities, mainly like-minded individuals are recruited, decision-making is carried out at a slow pace and on the basis of democratic processes, etc. Many of these characteristics can be seen in DOPPS, which functions as an amalgamation of an organization and a network or a community. The organization therefore complements the symbiotic network or community and creates an entity that cannot be illustrated with a simple two-dimensional model such as organizational chart. Two models of cooperation are intertwined in an orgunity: a hierarchical organization with a pyramid structure and a horizontal community or a network of volunteers in which relationships are constantly redefined.
6. Bleeding-Heart Liberals and Hard-Hearted Conservatives: Subtle Political Dehumanization Through Differential Attributions of Human Nature and Human Uniqueness Traits
Directory of Open Access Journals (Sweden)
Jarret T. Crawford
2013-10-01
Full Text Available This research demonstrated that human nature (HN and human uniqueness (HU traits capture the content of Americans’ stereotypes about liberals and conservatives, respectively. Consistent with expectations derived from dehumanization theory, people more strongly associated HN traits with liberals than with conservatives, and more strongly associated HU traits with conservatives than with liberals. A trait × target ideology × perceiver ideology × trait valence interaction suggested that both liberals and conservatives more strongly associated their ingroup with stereotype-consistent positive traits, and their outgroup with stereotype-consistent negative traits. Mediation analyses revealed that outgroup antipathy, but not ingroup liking, explained the relationship between ideology and political outgroup dehumanization. Finally, humanness traits captured subtle differences in political stereotype content not captured with the warmth and competence dimensions derived from the stereotype content model. Together, these results indicate that differential attributions of HN and HU traits capture political stereotype content and function to subtly dehumanize one’s political opponents.
7. Algal chemodiversity and bioactivity: sources of natural variability and implications for commercial application.
Science.gov (United States)
Stengel, Dagmar B; Connan, Solène; Popper, Zoë A
2011-01-01
There has been significant recent interest in the commercial utilisation of algae based on their valuable chemical constituents many of which exhibit multiple bioactivities with applications in the food, cosmetic, agri- and horticultural sectors and in human health. Compounds of particular commercial interest include pigments, lipids and fatty acids, proteins, polysaccharides and phenolics which all display considerable diversity between and within taxa. The chemical composition of natural algal populations is further influenced by spatial and temporal changes in environmental parameters including light, temperature, nutrients and salinity, as well as biotic interactions. As reported bioactivities are closely linked to specific compounds it is important to understand, and be able to quantify, existing chemical diversity and variability. This review outlines the taxonomic, ecological and chemical diversity between, and within, different algal groups and the implications for commercial utilisation of algae from natural populations. The biochemical diversity and complexity of commercially important types of compounds and their environmental and developmental control are addressed. Such knowledge is likely to help achieve higher and more consistent levels of bioactivity in natural samples and may allow selective harvesting according to algal species and local environmental conditions for different groups of compounds.
8. Polymer films removed from solid surfaces by nanostructured fluids: microscopic mechanism and implications for the conservation of cultural heritage.
Science.gov (United States)
Raudino, Martina; Selvolini, Giulia; Montis, Costanza; Baglioni, Michele; Bonini, Massimo; Berti, Debora; Baglioni, Piero
2015-03-25
Complex fluids based on amphiphilic formulations are emerging, particularly in the field of conservation of works of art, as effective and safe liquid media for the removal of hydrophobic polymeric coatings. The comprehension of the cleaning mechanism is key to designing tailored fluids for this purpose. However, the interaction between nanostructured fluids and hydrophobic polymer films is still poorly understood. In this study, we show how the combination of confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM) provides interesting and complementary insight into this process. We focused on the interaction between an ethyl methacrylate/methyl acrylate 70:30 copolymer film deposited onto a glass surface and a water/nonionic surfactant/2-butanone (MEK) ternary system, with MEK being a good solvent and water being a nonsolvent for the polymer. Our results indicate a synergy between the organic solvent and the surfactant assemblies: MEK rapidly swells the outer layers of the polymer film allowing for the subsequent diffusion of solvent molecules, while the amphiphile decreases the interfacial energy between the polymeric coating and the liquid phase, favoring dewetting and dispersion of swollen polymer droplets in the aqueous phase. The chemical nature of the surfactant and the microstructure of the assemblies determine both the kinetics and the overall efficiency of polymer removal, as assessed by comparing the behavior of similar formulations containing an anionic surfactant (sodium dodecyl sulfate, SDS).
9. Assessing Habitat Quality of Forest-Corridors through NDVI Analysis in Dry Tropical Forests of South India: Implications for Conservation
Directory of Open Access Journals (Sweden)
Paramesha Mallegowda
2015-02-01
Full Text Available Most wildlife habitats and migratory routes are extremely threatened due to increasing demands on forestland and forest resources by burgeoning human population. Corridor landscape in Biligiri Rangaswamy Temple Tiger Reserve (BRT is one among them, subjected to various anthropogenic pressures. Human habitation, intensive farming, coffee plantations, ill-planned infrastructure developments and rapid spreading of invasive plant species Lantana camara, pose a serious threat to wildlife habitat and their migration. Aim of this work is to create detailed NDVI based land change maps and to use them to identify time-series trends in greening and browning in forest corridors in the study area and to identify the drivers that are influencing the observed changes. Over the four decades in BRT, NDVI increased in the core area of the forest and reduced in the fringe areas. The change analysis between 1973 and 2014 shows significant changes; browning due to anthropogenic activities as well as natural processes and greening due to Lantana spread. This indicates that the change processes are complex, involving multiple driving factors, such as socio-economic changes, high population growth, historical forest management practices and policies. Our study suggests that the use of updated and accurate change detection maps will be useful in taking appropriate site specific action-oriented conservation decisions to restore and manage the degraded critical wildlife corridors in human-dominated landscape.
10. Longevity of Juniperus procera seed lots under different storage conditions: implications for ex situ conservation in seed banks
Institute of Scientific and Technical Information of China (English)
Negash Mamo; Diriba Nigusie; Mulualem Tigabu; Demel Teketay; Miftah Fekadu
2011-01-01
Juniperus procera Endl. Is economically important timberspecies, but its populations are extremely small and fragmented in itsnatural habitat, thus, calling for immediate ex situ conservation. Here weexamined the effects of seed sources and storage temperature on thelongevity of Juniperus procera seed lots through collection and preserva-tion of seeds in seed banks. Seeds were collected from nine sites acrossthe species natural distribution in Ethiopia and stored in four warehouses:modern cold room (5℃), mud house (15℃), concrete block house (17℃)or corrugated iron house (20℃) for 42 months. Every three months, arandom sample of stored seeds were drawn and tested for germination. Ahighly significant variation (p 0.80; p<0.01). Cold storage also resulted in enhancement ofgermination through its stratification effect that terminated the non-deepphysiological dormancy of juniper seeds. In conclusion, seed lots withgood initial germination can be effectively stored in cold room (5℃) upto four years. In the absence of modern cold stores, mud houses can beused as a good altemative to store seeds at local level.
11. Implications of rural-urban migration for conservation of the Atlantic Forest and urban growth in Misiones, Argentina (1970-2030).
Science.gov (United States)
Izquierdo, Andrea E; Grau, Héctor R; Aide, T Mitchell
2011-05-01
Global trends of increasing rural-urban migration and population urbanization could provide opportunities for nature conservation, particularly in regions where deforestation is driven by subsistence agriculture. We analyzed the role of rural population as a driver of deforestation and its contribution to urban population growth from 1970 to the present in the Atlantic Forest of Argentina, a global conservation priority. We created future land-use-cover scenarios based on human demographic parameters and the relationship between rural population and land-cover change between 1970 and 2006. In 2006, native forest covered 50% of the province, but by 2030 all scenarios predicted a decrease that ranged from 18 to 39% forest cover. Between 1970 and 2001, rural migrants represented 20% of urban population growth and are expected to represent less than 10% by 2030. This modeling approach shows how rural-urban migration and land-use planning can favor nature conservation with little impact on urban areas.
12. Policy outline for the conservation of Peru's renewable natural resources. Lineamientos de politica de conservacion de los recursos naturales renovables del Peru
Energy Technology Data Exchange (ETDEWEB)
1974-01-01
Information is presented on proposed programs for the conservation of coastal, marine, and mountain region natural resources of Peru, including the introduction of legislation, education, and management. Studies are also made on soil erosion prevention, wildlife preservation, desalination programs, and land reclamation.
13. Nature, frequency and duration of genital lesions after consensual sexual intercourse-Implications for legal proceedings
DEFF Research Database (Denmark)
Astrup, Birgitte Schmidt; Ravn, Pernille; Lauritsen, Jens
2012-01-01
OBJECTIVE: The purpose of this study was to make a normative description of the nature and duration of genital lesions sustained during consensual sexual intercourse, using the three most commonly used techniques; visualisation using the naked eye, colposcopy and toluidine blue dye followed...... by colposcopy. METHODS: Ninety eight women were examined within 48h of consensual sexual intercourse. Fifty of the women were examined twice again within the following 7 days of sexual abstinence after the first examination. RESULTS: The participants had a median age of 22.4 years and 88% were nulliparous....... Lesions were frequent; 34% seen with the naked eye, 49% seen with colposcopy and 52% seen with toluidine blue dye and subsequent colposcopy. The lesions lasted for several days; the median survival times for lacerations were 24, 40 and 80h, respectively. CONCLUSIONS: The legal implications...
14. How (not to draw philosophical implications from the cognitive nature of concepts: The case of intentionality
Directory of Open Access Journals (Sweden)
Kazuki eIijima
2014-07-01
Full Text Available Philosophers have often appealed to intuitive judgments in various thought experiments to support or reject particular theses. Experimental philosophy is an emerging discipline that examines the cognitive nature of such intuitive judgments. In this paper, we assess the methodological and epistemological status of experimental philosophy. We focus on the Knobe effect, in which our intuitive judgment of the intentionality of an action seems to depend on the perceived moral status of that action. The debate on the philosophical implications of the Knobe effect has been framed in terms of the distinction between the competence and performance of the concept of intentionality. Some scholars seem to suggest that the Knobe effect reflects the competence (or otherwise, the performance error of the concept of intentionality. However, we argue that these notions are purely functional and thus do not have philosophical implications, without assuming normativism, which we see as problematic in a psychological methodology. Finally, focusing on the gap between competence and rationality, we suggest future directions for experimental philosophy.
15. Environmental philosophy 2.0: ethics and conservation biology for the 21st century.
Science.gov (United States)
Odenbaugh, Jay
2014-03-01
In this essay, I critically engage Sahotra Sarkar's Environmental Philosophy. The several topics include the conceptual foundations of conservation biology and traditional philosophy of science, naturalism and its implications, and ethical theory and specifically the status of human welfare.
16. Geography of conservation spending, biodiversity, and culture.
Science.gov (United States)
McClanahan, T R; Rankin, P S
2016-10-01
We used linear and multivariate models to examine the associations between geography, biodiversity, per capita economic output, national spending on conservation, governance, and cultural traits in 55 countries. Cultural traits and social metrics of modernization correlated positively with national spending on conservation. The global distribution of this spending culture was poorly aligned with the distribution of biodiversity. Specifically, biodiversity was greater in the tropics where cultures tended to spend relatively less on conservation and tended to have higher collectivism, formalized and hierarchical leadership, and weaker governance. Consequently, nations lacking social traits frequently associated with modernization, environmentalism, and conservation spending have the largest component of Earth's biodiversity. This has significant implications for setting policies and priorities for resource management given that biological diversity is rapidly disappearing and cultural traits change slowly. Therefore, we suggest natural resource management adapt to and use characteristics of existing social organization rather than wait for or promote social values associated with conservation spending. Supporting biocultural traditions, engaging leaders to increase conservation commitments, cross-national efforts that complement attributes of cultures, and avoiding interference with nature may work best to conserve nature in collective and hierarchical societies. Spending in modernized nations may be a symbolic response to a symptom of economic development and environmental degradation, and here conservation actions need to ensure that biodiversity is not being lost. © 2016 Society for Conservation Biology.
17. Wildlife Conservation
OpenAIRE
Clive L. Spash; Aldred, Jonathan
1998-01-01
In this paper we consider how conservation has arisen as a key aspect of the reaction to human-initiated degradation and disappearance of ecosystems, wild lands. and wildlife. Concern over species extinction is given an historical perspective which shows the way in which pressure on wild and natural aspects of global ecology have changed in recent centuries. The role of conservation in the struggle to protect the environment is then analysed using underlying ethical arguments behind the econo...
18. Increase in Total Joint Arthroplasty Projected from 2014 to 2046 in Australia: A Conservative Local Model With International Implications.
Science.gov (United States)
Inacio, Maria C S; Graves, Stephen E; Pratt, Nicole L; Roughead, Elizabeth E; Nemes, Szilard
2017-08-01
100,000; 95% PI, 402-717 per 100,000) compared with 2013 (IR = 437 per 100,000; 95% CI, 397-479 per 100,000) and the volume to increase by 142%. A large increase in the volume of arthroplasties is expected using a conservative projection model that accounts for past surgical trends and future population changes in Australia. These findings have international implications, as they show that using country- specific, conservative projection approaches, a substantial increase in the number of these procedures is expected. This increase in joint arthroplasty volume will require appropriate workforce planning, resource allocation, and budget planning so that demand can be met. Level II, economic and decision analysis.
19. The Coupled Nature of C and N Cycles in Forest Ecosystems: Evidence, Implications and Uncertainties
Science.gov (United States)
Ollinger, S. V.; Aber, J. D.; Sievering, H.
2001-12-01
Cycles of carbon and nitrogen in forest ecosystems are mutually and interactively linked through a shared set of biological processes. A large number of field studies across diverse biomes have documented strong and generalizable relationships between foliar nitrogen concentrations and rates of net photosynthesis. This trend reflects the fact that the majority of N in plant canopies is found in the proteins responsible for CO2 capture (e.g. rubisco). In soils, the accumulation and availability of nitrogen is, in turn, affected by the quality and N content of litter inputs from vegetation. Taken together, these patterns reflect the broadly-coupled nature of terrestrial C and N cycles and suggest that human alteration of any aspect of one cycle can have important implications for the other. Nevertheless, the exact nature of C-N interactions in natural ecosystems can depend on a variety of factors including historical disturbance patterns, the effects of carbon quality on decomposition and N turnover, and the resulting differences in plant-soil feedbacks among species and functional groups. All of these factors greatly complicate efforts to characterize present-day patterns of C and N fluxes across real forested landscapes. Further, human-induced increases in atmospheric CO2 and N deposition hold the potential for either tightening the linkages between C and N cycles, or causing them to become uncoupled. This presentation will build on basic concepts to address several broad questions regarding C-N interactions in forests, both as they occur naturally and as they may be affected by elevated CO2 or N deposition: 1) What evidence is available from the field to demonstrate the coupled nature of C-N cycles in native forest ecosystems? 2) How are C-N interactions in forests influenced by the growth and allocation strategies of different species and/or functional groups? 3) To what degree are current C and N cycles reflected in the chemistry of forest foliage, and 4) Is
20. Cover crop management practices-implications for early season weed control in conservation tillage corn cotton rotation
Science.gov (United States)
Use of the winter cover crops is an integral component of the conservation systems in corn (Zea mays L.) and cotton (Gossypium hirsutum L.). A field experiment was initiated in 2004 to evaluate weed suppression provided by winter cover crops in a conservation tillage corn and cotton rotation. Rotati...
1. Determinants of Persistence and Tolerance of Carnivores on Namibian Ranches: Implications for Conservation on Southern African Private Lands
NARCIS (Netherlands)
Lindsey, P.A.; Havemann, C.P.; Lines, R.M.; Palazy, L.; Price, A.E.; Retief, T.A.; Rhebergen, T.; Waal, van der C.
2013-01-01
Changing land use patterns in southern Africa have potential to dramatically alter the prospects for carnivore conservation. Understanding these influences is essential for conservation planning. We interviewed 250 ranchers in Namibia to assess human tolerance towards and the distribution of large
2. Conservation management improves runoff water quality: Implications for environmental sustainability in a glyphosate-resistant cotton production system
Science.gov (United States)
Studies suggest that coincidental adoption of both genetically modified crops (GMC) and conservation management may be mutually complementary, but integrated conservation systems with GMC’s need to be assessed to balance production goals with environmental concerns. Genetically modified cotton (Gos...
3. Diversity and distribution of aquatic insects in Southern Brazil wetlands: implications for biodiversity conservation in a Neotropical region
Directory of Open Access Journals (Sweden)
Leonardo Maltchik
2012-03-01
Full Text Available The selection of priority areas is an enormous challenge for biodiversity conservation. Some biogeographic methods have been used to identify the priority areas to conservation, and panbiogeography is one of them. This study aimed at the utilization of panbiogeographic tools, to identify the distribution patterns of aquatic insect genera, in wetland systems of an extensive area in the Neotropical region (~280 000km², and to compare the distribution of the biogeographic units identified by the aquatic insects, with the conservation units of Southern Brazil. We analyzed the distribution pattern of 82 genera distributed in four orders of aquatic insects (Diptera, Odonata, Ephemeroptera and Trichoptera in Southern Brazil wetlands. Therefore, 32 biogeographic nodes corresponded to the priority areas for conservation of the aquatic insect diversity. Among this total, 13 were located in the Atlantic Rainforest, 16 in the Pampa and three amongst both biomes. The distribution of nodes showed that only 15% of the dispersion centers of insects were inserted in conservation units. The four priority areas pointed by node cluster criterion must be considered in further inclusions of areas for biodiversity conservation in Southern Brazil wetlands, since such areas present species from differrent ancestral biota. The inclusion of such areas into the conservation units would be a strong way to conserve the aquatic biodiversity in this region.
4. Diversity and distribution of aquatic insects in Southern Brazil wetlands: implications for biodiversity conservation in a Neotropical region.
Science.gov (United States)
Maltchik, Leonardo; Dalzochio, Marina Schmidt; Stenert, Cristina; Rolon, Ana Silvia
2012-03-01
The selection of priority areas is an enormous challenge for biodiversity conservation. Some biogeographic methods have been used to identify the priority areas to conservation, and panbiogeography is one of them. This study aimed at the utilization of panbiogeographic tools, to identify the distribution patterns of aquatic insect genera, in wetland systems of an extensive area in the Neotropical region (approximately 280 000km2), and to compare the distribution of the biogeographic units identified by the aquatic insects, with the conservation units of Southern Brazil. We analyzed the distribution pattern of 82 genera distributed in four orders of aquatic insects (Diptera, Odonata, Ephemeroptera and Trichoptera) in Southern Brazil wetlands. Therefore, 32 biogeographic nodes corresponded to the priority areas for conservation of the aquatic insect diversity. Among this total, 13 were located in the Atlantic Rainforest, 16 in the Pampa and three amongst both biomes. The distribution of nodes showed that only 15% of the dispersion centers of insects were inserted in conservation units. The four priority areas pointed by node cluster criterion must be considered in further inclusions of areas for biodiversity conservation in Southern Brazil wetlands, since such areas present species from different ancestral biota. The inclusion of such areas into the conservation units would be a strong way to conserve the aquatic biodiversity in this region.
5. Determinants of Persistence and Tolerance of Carnivores on Namibian Ranches: Implications for Conservation on Southern African Private Lands
NARCIS (Netherlands)
Lindsey, P.A.; Havemann, C.P.; Lines, R.M.; Palazy, L.; Price, A.E.; Retief, T.A.; Rhebergen, T.; Waal, van der C.
2013-01-01
Changing land use patterns in southern Africa have potential to dramatically alter the prospects for carnivore conservation. Understanding these influences is essential for conservation planning. We interviewed 250 ranchers in Namibia to assess human tolerance towards and the distribution of large c
6. Implications of cancer stem cell theory for cancer chemoprevention by natural dietary compounds.
Science.gov (United States)
Li, Yanyan; Wicha, Max S; Schwartz, Steven J; Sun, Duxin
2011-09-01
The emergence of cancer stem cell theory has profound implications for cancer chemoprevention and therapy. Cancer stem cells give rise to the tumor bulk through continuous self-renewal and differentiation. Understanding the mechanisms that regulate self-renewal is of greatest importance for discovery of anticancer drugs targeting cancer stem cells. Naturally occurring dietary compounds have received increasing attention in cancer chemoprevention. The anticancer effects of many dietary components have been reported for both in vitro and in vivo studies. Recently, a number of studies have found that several dietary compounds can directly or indirectly affect cancer stem cell self-renewal pathways. Herein we review the current knowledge of most common natural dietary compounds for their impact on self-renewal pathways and potential effect against cancer stem cells. Three pathways (Wnt/β-catenin, Hedgehog and Notch) are summarized for their functions in self-renewal of cancer stem cells. The dietary compounds, including curcumin, sulforaphane, soy isoflavone, epigallocatechin-3-gallate, resveratrol, lycopene, piperine and vitamin D(3), are discussed for their direct or indirect effect on these self-renewal pathways. Curcumin and piperine have been demonstrated to target breast cancer stem cells. Sulforaphane has been reported to inhibit pancreatic tumor-initiating cells and breast cancer stem cells. These studies provide a basis for preclinical and clinical evaluation of dietary compounds for chemoprevention of cancer stem cells. This may enable us to discover more preventive strategies for cancer management by reducing cancer resistance and recurrence and improving patient survival.
7. Assessment of natural regeneration status and diversity of tree species in the biodiversity conservation areas of Northeastern Bangladesh
Institute of Scientific and Technical Information of China (English)
Md. Habibur Rahman; Md. Abu Sayed Arfin Khan; Bishwajit Roy; Most. Jannatul Fardusi
2011-01-01
A study was conducted at two-biodiversity conservation areas of Northeastern Bangladesh (a part of Sylhet Forest Division) to assess the species composition,diversity and density of natural regeneration of ~ species both indigenous and exotic species.Data were collected by stratified random quadrate method during January 2010 to July 2010.Totally 200 circular plots of 2 m×2 m in size had 5 different habitat types of plants namely; forest,roadside,homestead (surrounding forest dwellers house),fallow land and others (canals,streams and tea gardens side),which included a total of 55 regenerating species belonging to 28 families.Meliaceae is the dominant family and shows the.highest family importance value (26.3),having six species,followed,by Moraceae (24.24).Among the five habitat types,forest (43 species) possess the highest number of species,followed by roadside (23 species).Total 15 exotic species among 9 families and 40 indigenous spocies vith 24 families were recorded.For exotic species,Tectona grandis possess the highest relative density (11.7%) and relative frequency (10.5%); Senna siamea had highest relative abundance (7.83%).In case of indigenous species,Chickrassia tabularis possess the highest relative density (4.23%)and relative frequency (4%); Dipterocarpus turbinatus had the highest relative abundance (3.92%).Tectona grandis (29.66) and Chickrassia tabularis(10.8) had the highest IVI for exotic and indigenous species respectively.Different diversity indices such as Shanon-Winner diversity index,species diversity index,species richness index,species evenness index,Simpson index and species dominance index,etc.were applied to quantify definite diversity.The regeneration of species associated with low levels of disturbance was in the exotic species.Study suggests that proper protection from human disturbances and scientific management of natural regeneration of two-study forests may lead a rich biodiversity site in the country.
8. Contrasting fish assemblages in free-flowing and impounded tributaries to the Upper Delaware River: Implications for conserving biodiversity
Science.gov (United States)
Baldigo, Barry P.; Delucia, Mari-Beth; Keller, Walter D.; Schuler, George E.; Apse, Colin D.; Moberg, Tara
2015-01-01
The Neversink River and the Beaver Kill in southeastern New York are major tributaries to the Delaware River, the longest undammed river east of the Mississippi. While the Beaver Kill is free flowing for its entire length, the Neversink River is subdivided by the Neversink Reservoir, which likely affects the diversity of local fish assemblages and health of aquatic ecosystems. The reservoir is an important part of the New York City waster-supply system that provides drinking water to more than 9 million people. Fish population and community data from recent quantitative surveys at comparable sites in both basins were assessed to characterize the differences between free-flowing and impounded rivers and the extent of reservoir effects to improve our capacity to define ecosystems responses that two modified flow-release programs (implemented in 2007 and 2011) should produce in the Neversink River. In general, the continuum of changes in fish assemblages which normally occur between headwaters and mouth was relatively uninterrupted in the Beaver Kill, but disrupted by the mid-basin impoundment in the Neversink River. Fish assemblages were also adversely affected at several acidified sites in the upper Neversink River, but not at most sites assessed herein. The reservoir clearly excluded diadromous species from the upper sub-basin, but it also substantially reduced community richness, diversity, and biomass at several mid-basin sites immediately downstream from the impoundment. There results will aid future attempts to determine if fish assemblages respond to more natural, yet highly regulated, flow regimes in the Neversink River. More important, knowledge gained from this study can help optimize use of valuable water resources while promoting species of special concern, such as American eel (Anguilla rostrata) and conserving biodiversity in Catskill Mountain streams.
9. Non-stationarity of "Nature's Limit" - Implications for Agriculture in Semi-arid Environments
Science.gov (United States)
Tozer, C.; Kiem, A.; Verdon-Kidd, D.
2014-12-01
"Rain follows the plow" was a theory that encouraged agricultural settlement in dryland areas in both the United States of America and Australia during the mid-1800s. Supporters of the theory believed that humans could master nature and alter the climate through cultivation of the soil. An opponent of this theory was George W. Goyder, who used vegetation in South Australia as an indicator to mark out the extent of the area's severe 1865 drought, effectively establishing "nature's limit" to reliable agriculture in South Australia. This limit became known as Goyder's Line and demarked the boundary between land suitable for agricultural pursuits (i.e. cropping) to the south and land only suitable for grazing in the State's arid north. Current cropping areas however extend north beyond this line, suggesting that either a) the line is not well defined, b) cropping is occurring on land considered 'non-viable' according to Goyder's Line or c) the line distinguishing where cropping is and is not viable varies on interannual to multidecadal timescales. In this study, the 220 mm growing season (April to October) rainfall isohyet is used as a proxy for Goyder's Line in order to assess its temporal and spatial variability. Using indices of the El Niño/Southern Oscillation, Indian Ocean variability, Southern Annular Mode and the Subtropical Ridge, it is shown that climate state significantly influences the location of the 220 mm growing season rainfall isohyet. This implies that the boundary between viable and non-viable cropping areas (i.e. Goyder's Line or "nature's limit") is non-stationary. These results also indicate the key influences on South Australia's climate and have important implications globally for agricultural practices operating in or bordering semi-arid environments.
10. Lessons to be Learnt from Natural Control of HIV – Future Directions, Therapeutic and Preventive Implications
Directory of Open Access Journals (Sweden)
David eShasha
2013-06-01
Full Text Available Accumulating data generated from persons who naturally control HIV without the need for antiretroviral treatment has led to significant insights into the mechanisms of durable control of AIDS virus infection. At the center of this control is the HIV-specific CD8 T cell response, and the basis for this CD8-mediated control is gradually being revealed. Genome wide association studies coupled with HLA sequence data implicate the nature of the HLA-viral peptide interaction as the major genetic factor modulating durable control of HIV, but that host genetic factors account for only around 20% of the variability in control. Other factors including specific functional characteristics of the TCR clonotypes generated in vivo, targeting of vulnerable regions of the virus that lead to fitness impairing mutations, immune exhaustion and host restriction factors that limit HIV replication all have been shown to additionally contribute to control. Moreover, emerging data indicate that the CD8 T cell response may be critical for attempts to purge virus infected cells following activation of the latent reservoir, and thus lessons learned from elite controllers are likely to impact the eradication agenda. Ongoing efforts are also needed to understand and address the role of immune activation in disease progression, as it becomes increasingly clear that durable immune control in elite controllers comes at a cost. Taken together, the research achievements in the attempt to unlock the mechanisms behind natural control of HIV will continue to be an important source of insights and ideas in the continuous search after an effective HIV vaccine, and for the attempts to achieve a sterilizing or functional cure in HIV positive patients with progressive infection.
11. Genomics and the future of conservation genetics.
Science.gov (United States)
Allendorf, Fred W; Hohenlohe, Paul A; Luikart, Gordon
2010-10-01
We will soon have complete genome sequences from thousands of species, as well as from many individuals within species. This coming explosion of information will transform our understanding of the amount, distribution and functional significance of genetic variation in natural populations. Now is a crucial time to explore the potential implications of this information revolution for conservation genetics and to recognize limitations in applying genomic tools to conservation issues. We identify and discuss those problems for which genomics will be most valuable for curbing the accelerating worldwide loss of biodiversity. We also provide guidance on which genomics tools and approaches will be most appropriate to use for different aspects of conservation.
12. Conservazione programmata: i risvolti economici di un cambio di paradigma / Planned conservation: the economic implications of a paradigm shift
Directory of Open Access Journals (Sweden)
Stefano Della Torre
2010-10-01
Planned conservation is an innovative procedure, stepping from restoration as event, to preservation as long-term process. It is something more than maintenance and monitoring: it is a rather complex strategy, merging a large scale reduction of risks and a careful organization of daily activities. Implementing planned conservation, therefore, is something more effective than implementing maintenance: it means setting a totally new scenario, posing questions about strategies and links between preservation activities and local development processes. This paper introduces planned conservation as an attempt to go beyond the basic statement that Heritage counts because of its impact on economy of tourism. The research program focuses on external benefits of conservation processes. If human capital becomes an interesting parameter to evaluate an economy, conservation counts because of its impact on capability to doubt, to learn, to innovate: in other words, focus shifts from Heritage, as a given asset, to conservation processes as opportunities to increase intellectual capital. The thesis is that planned conservation yields more of external benefits and makes their management easier than in traditional restoration model.
13. Backscattering by Non-spherical Natural Particles: Instrument Development, IOP’s, and Implications for Radiative Transfer
Science.gov (United States)
2016-06-07
Backscattering by Non-spherical Natural Particles: Instrument Development, IOP’s, and Implications for Radiative Transfer Yogesh Agrawal... natural particles from a standpoint of measuring size-distribution; (ii) Understand how the properties of particles (composition, shape, and internal...applied to predicting light propagation in the sea by providing as input, the new estimates of IOP’s. This work is relevant to ONR’s Sensor and
14. A Conservation Ethic and the Collecting of Animals by Institutions of Natural Heritage in the Twenty-First Century: Case Study of the Australian Museum.
Science.gov (United States)
Ikin, Timothy
2011-02-15
Collecting of animals from their habitats for preservation by museums and related bodies is a core operation of such institutions. Conservation of biodiversity in the current era is a priority in the scientific agendas of museums of natural heritage in Australia and the world. Intuitively, to take animals from the wild, while engaged in scientific or other practices that are supposed to promote their ongoing survival, may appear be incompatible. The Australian Museum presents an interesting ground to consider zoological collecting by museums in the twenty-first century. Anderson and Reeves in 1994 argued that a milieu existed that undervalued native species, and that the role of natural history museums, up to as late as the mid-twentieth century, was only to make a record the faunal diversity of Australia, which would inevitably be extinct. Despite the latter, conservation of Australia's faunal diversity is a key aspect of research programmes in Australia's institutions of natural heritage in the current era. This paper analyses collecting of animals, a core task for institutions of natural heritage, and how this interacts with a professed "conservation ethic" in a twenty-first century Australian setting.
15. A Conservation Ethic and the Collecting of Animals by Institutions of Natural Heritage in the Twenty-First Century: Case Study of the Australian Museum
Directory of Open Access Journals (Sweden)
Timothy Ikin
2011-02-01
Full Text Available Collecting of animals from their habitats for preservation by museums and related bodies is a core operation of such institutions. Conservation of biodiversity in the current era is a priority in the scientific agendas of museums of natural heritage in Australia and the world. Intuitively, to take animals from the wild, while engaged in scientific or other practices that are supposed to promote their ongoing survival, may appear be incompatible. The Australian Museum presents an interesting ground to consider zoological collecting by museums in the twenty-first century. Anderson and Reeves in 1994 argued that a milieu existed that undervalued native species, and that the role of natural history museums, up to as late as the mid-twentieth century, was only to make a record the faunal diversity of Australia, which would inevitably be extinct. Despite the latter, conservation of Australia’s faunal diversity is a key aspect of research programmes in Australia’s institutions of natural heritage in the current era. This paper analyses collecting of animals, a core task for institutions of natural heritage, and how this interacts with a professed “conservation ethic” in a twenty-first century Australian setting.
16. Nature conservation and grazing management. Free-ranging cattle as a driving force for cyclic vegetation seccession
NARCIS (Netherlands)
Bokdam, J.
2003-01-01
Key-words : biodiversity, herbivory, wilderness, non-linear dynamics, mosaic cycling, grassland, wood encroachment, forest, Bos taurus , Calluna vulgaris , Deschampsia flexuosa.This thesis examines the suitability of controlled and wilderness grazing as conservation management tool for open, nutrien
17. Implication upon Herpetofauna of a Road and its Reconstruction in Carei Plain Natural Protected Area (Romania
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Alfred-S. Cicort-Lucaciu
2012-07-01
Full Text Available In autumn 2011 we monitored a 5 km long road, paved with cobblestone, situated in Carei Plain Natural Protected Area, a road that is due to be modernized and continued across the border into Hungary. Dead bodies from eight different animal groups were observed on the road, amphibians presenting the greatest amount. The most frequent were the Triturus dobrogicus corps, a species with conservation importance. The amphibians were affected in the areas where the road is neighboring the wetlands, while on the opposite pole sits the area with acacia plantations. The high number of mortalities recorded on the road, despite the low traffic speed, is alarming. It is likely that the modernization of the road that will surely increase its traffic and the speed of the vehicles, will make the situation even worse. However, the rebuilding could contribute to the reduction in the impact on amphibians, if certain measures are considered while planning the action. Thus, in the areas near the wetlands, there should be undercrossings, fences and speed limits. In this way, the modernization would at least represent an experiment regarding the diminution of the road’s impact on amphibians.
18. Landscape, historic memory and national identity in the beginnings of the policy nature conservation in Spain: from Covadonga to San Juan de la Peña
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Jacobo García Álvarez
2013-08-01
Full Text Available This article reflects on the concept of “national landscape” and on the importance of identity symbolic values in the beginning of landscape and nature conservation policy in Spain. The emblematic case of the Montaña de Covadonga (the first National Park created in Spain is examined in more detail. The paper is divided into three main sections. The first one raises some theoretical and general considerations on the role of identity symbolic values within the first steps of nature conservation policies in Spain and other national contexts. Secondly, the cultural-historic processes and discourses which converted the Montaña de Covadonga landscape into a Spanish national symbol and into a site of memory, leading to its declaration as a National Park in 1918, are reviewed. The third section examines the ideological identity disputes and controversies concerning the creation of that National Park, some of which led to the declaration of the Sitio Nacional del Monte de San Juan de la Peña in 1920. The article approaches the creation of the first Spanish Natural Parks as a part of the nationalization policies inspired by the concerns of the “Regeneracionismo”. More precisely, the beginning of natural conservation policy in Spain may be considered as part of the efforts carried out by certain intellectual and political leaders in order to institutionalize new spaces of collective identity grounded in landscape and nature (and, more particularly, in some natural landscapes endowed with a strong historic symbolic meaning as regards to the “birth of the nation”. According to the research conclusions, the ideological controversies raised around the first Spanish Natural Parks can be understood as a reflection of the plurality of competing national conceptions existing in Spain, as well as of the difficulties in reaching a consensus on the country’s national symbols.
19. The topology of the bacterial co-conserved protein network and its implications for predicting protein function
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Leach Sonia M
2008-06-01
Full Text Available Abstract Background Protein-protein interactions networks are most often generated from physical protein-protein interaction data. Co-conservation, also known as phylogenetic profiles, is an alternative source of information for generating protein interaction networks. Co-conservation methods generate interaction networks among proteins that are gained or lost together through evolution. Co-conservation is a particularly useful technique in the compact bacteria genomes. Prior studies in yeast suggest that the topology of protein-protein interaction networks generated from physical interaction assays can offer important insight into protein function. Here, we hypothesize that in bacteria, the topology of protein interaction networks derived via co-conservation information could similarly improve methods for predicting protein function. Since the topology of bacteria co-conservation protein-protein interaction networks has not previously been studied in depth, we first perform such an analysis for co-conservation networks in E. coli K12. Next, we demonstrate one way in which network connectivity measures and global and local function distribution can be exploited to predict protein function for previously uncharacterized proteins. Results Our results showed, like most biological networks, our bacteria co-conserved protein-protein interaction networks had scale-free topologies. Our results indicated that some properties of the physical yeast interaction network hold in our bacteria co-conservation networks, such as high connectivity for essential proteins. However, the high connectivity among protein complexes in the yeast physical network was not seen in the co-conservation network which uses all bacteria as the reference set. We found that the distribution of node connectivity varied by functional category and could be informative for function prediction. By integrating of functional information from different annotation sources and using the
20. Practical implications of increasing 'natural living' through suckling systems in organic dairy calf rearing; Theme: Values in Organic Agriculture
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Wagenaar, J.P.; Langhout, D.J.
2007-01-01
The introduction of suckling systems in organic dairy calf rearing has the potential to enhance animal welfare in terms of ‘natural living’ and to live up to consumers’ expectations about organic agriculture. This study describes the implications of suckling systems in a practical organic dairy cont
1. Comparative study of conservation of fresh cassava roots (Manihot esculenta Crantz coated with natural wax and paraffin; Estudio comparativo de conservación de raíces de yuca (Manihot esculenta Crantz recubiertas con cera natural y parafina
Directory of Open Access Journals (Sweden)
Lisímaco Alonso Alcalá
2013-06-01
Full Text Available Cassava roots are very susceptible to physiological deterioration; after a few days of harvesting (two or three they are not acceptable for consumption. For this reason, diverse methods have been developed for their preservation, for example, coating them with paraffin, which prolongs the product’s shelf life up to 15 days.This conservation method with paraffin has some disadvantages from the environmental point of view because this coating is a hydrocarbon derived from petroleum and it is applied hot to the roots (temperatures above 120 °C. Thereby, it is important to seek alternatives of environmentally friendly preservation.This work evaluated the effectiveness of root coating with natural wax as a possible substitute for paraffin for the conservation of the product under natural environmental conditions.The results showed that natural wax is as effective as paraffin in preserving cassava roots; it delays physiological deterioration, as well as weight and dry matter losses
2. Implication of conservative and gyroscopic forces on vibration and stability of an elastically tailored rotating shaft modeled as a composite thin-walled beam.
Science.gov (United States)
Song, O; Jeong, N H; Librescu, L
2001-03-01
Problems related with the implications of conservative and gyroscopic forces on vibration and the stability of a circular cylindrical shaft modeled as a thin-walled composite beam and spinning with constant angular speed about its longitudinal axis are addressed. Taking into account the directionality property of fiber reinforced composite materials, it is shown that for a shaft featuring flapwise-chordwise-bending coupling, a dramatic enhancement of both the vibrational and stability behavior can be reached. In addition, the effects played in the same context by transverse shear, rotatory inertias as well as by the various boundary conditions are discussed and pertinent conclusions are outlined.
3. Versatility and nuances of the architecture of haematopoiesis - Implications for the nature of leukaemia.
Science.gov (United States)
Brown, Geoffrey; Hughes, Philip J; Ceredig, Rhodri; Michell, Robert H
2012-01-01
For many years there was a widely accepted picture of how a haematopoietic stem cell (HSC) gives rise to the multiple types of blood and immune cells. This described the general nature of stem and progenitor cells and the pathways of cell development. Recent years have seen many attempts to re-draw the map of haematopoiesis. These have become increasingly complex, and they often envisage multiples routes to some cell types. The 'established' view that self-renewal in haematopoiesis only occurs in HSCs has been challenged by the recognition of self-renewing HSC-derived progenitor cells that display at least some fate restriction. This evolution of how normal haematopoiesis is viewed has inevitable implications for understanding the origins, disease progression and classification of the leukaemias. In essence, some progenitor cells are now seen as possessing a larger repertoire of routes to end-fates than was previously thought. This leads one to ask whether leukaemia stem cells are equally or less versatile than their normal counterparts? Copyright © 2011 Elsevier Ltd. All rights reserved.
4. Society's Growing Vulnerability to Natural Hazards and Implications for Geophysics Research (Invited)
Science.gov (United States)
Slingo, J.
2010-12-01
2010 is shaping up to be a year of unprecedented natural hazards - at least in living memory - which have raised our awareness of our vulnerability, challenged our scientific understanding and questioned our ability to predict and prepare for such events. This talk will take some examples from this year and use them to explore the implications for the research agenda in weather and climate modelling and prediction, and in how to translate our predictions into products and services that address user needs. Specific examples include the eruption of Eyjafjallajökull in Iceland, its impact on the aviation industry and the challenges that it posed to London Volcanic Ash Advisory Centre. The biblical proportions of the floods in Pakistan, and the Russian heat wave, wildfires and crop losses are examples of unprecedented events which have raised questions around climate change and the degree to which such events can be attributed or not to a warming world. The prospects of modelling and predicting these hazardous events and their impacts will be discussed in terms of our capabilities and what investments are needed in model development, supercomputing resources and the science of interdisciplinary impacts. Finally we live in an uncertain world, and preparedness requires us to take account of that uncertainty. The science challenges of moving towards more reliable and confident predictions that take us from uncertainty to probabilities and risk based assessments will be discussed.
5. Nature of Technology: Implications for design, development, and enactment of technological tools in school science classrooms
Science.gov (United States)
2012-12-01
This position paper provides a theory-based explanation informed by philosophy of technology (PoT) of the recurrent documented patterns often associated with attempts to enact technology-supported, inquiry-based approaches in precollege science classrooms. Understandings derived from the history of technological development in other domains (e.g. medicine, transportation, and warfare) reveal numerous parallels that help to explain these recurrent patterns. Historical analyses of major technologies reveal a conglomerate of factors that interact to produce benefits, as well as intended and unintended consequences. On a macro-scale, PoT facilitates understandings of how technologies interact and are impacted by individuals, society, institutions, economy, politics, and culture. At the micro-level, and most relevant to science education, PoT engages the inherent nature of technology along a number of key dimensions: role of culture and values, notions of technological progression, technology as part of systems, technological diffusion, technology as a fix, and the notions of expertise. Overall, the present analysis has implications for the design, development, implementation, and adoption of technological tools for use in precollege science education, and highlights the role of technology as both artifact and process.
6. Water in granulites: implications for the nature and evolution of the lower continental crust
Institute of Scientific and Technical Information of China (English)
YANG Xiaozhi; XIA Qunke; Etienne DELOULE; FAN Qicheng; HAO Yantao
2007-01-01
The lower continental crust is one of the most important sphere-layers in the deep earth, and is the direct place where the crust-mantle interactions occur. Granulites are the dominated rocks in the lower crust, and have critical implications for the knowledge of the composition, nature and evolution of the deep crust; fluids are important mediums influencing many geochemical, geophysical and geodynamical characteristics of the lower crust, and may also play a fundamental role in the petrogenesis of granulites and the formation of the lower crusts. In this paper, we review recent advances involved with the deep continental crust, granulites and fluids, and some longstanding debates. Combined with the Fourier-transform infrared spectroscopy (FTIR) analysis performed on the mineral assemblages (cpx, opx, plag and grt) in lower crustal granulite xenoliths and terrains (exposed section) from east China, it is suggested that structural water, dominated by OH, in these nominally anhydrous phases may constitute the most important water reservoir in the deep crust. This structual water may help to understand many lower crustal geological processes and phenomena (e. G. Seismic activities and electrical conductive anomalies), and influences from these water must be taken into consideration.
7. Beyond the "general public": implications of audience characteristics for promoting species conservation in the Western Ghats hotspot, India.
Science.gov (United States)
Kanagavel, Arun; Raghavan, Rajeev; Veríssimo, Diogo
2014-03-01
Understanding how different audience groups perceive wildlife is crucial for the promotion of biodiversity conservation, especially given the key role of flagship species in conservation campaigns. Although the heterogeneity in preferences reinforces the need for campaigns tailored to specific target audiences, many conservation education and awareness campaigns still claim to target the "general public". Audiences can be segmented according to social, economic, and cultural criteria across which species perceptions are known to vary. Different studies have investigated the preferences of different groups towards certain wildlife species, but these are largely confined to a single conservation stakeholder group, such as tourists, local communities, or potential donors in western countries. In this study, we seek to determine from a multi-stakeholder perspective, audience characteristics that influence perceptions towards wildlife at Valparai, a fragmented plateau in the Western Ghats region of the Western Ghats-Sri Lanka Hotspot. We found that stakeholder group membership was the most important characteristic followed by gender. While some characteristics had a wide-scale effect others were restricted to a few species. Our results emphasize the need to design conservation campaigns with specific audiences in mind, instead of the very often referred to "general public".
8. Dormancy Breaking and Storage Behavior of Garcinia cowa Roxb. (Guttiferae) Seeds: Implications for Ecological Function and Germplasm Conservation
Institute of Scientific and Technical Information of China (English)
Yong LIU; Yu-Ping QIU; Ling ZHANG; Jin CHEN
2005-01-01
The dormancy breaking and storage behavior of Garcinia cowa Roxb. seeds were investigated.The seeds of G. cowa had 8-11 months dormancy in their natural habitat. Seeds were matured and dispersed at the end of the rainy season (mid-late August to late September) and were scatter-hoarded by rodents as food for winter after the seeds had fallen to the ground. Seedlings often emerged in the forest during the rainy season (May to August) the following year. Intact seeds of G. cowa failed to germinate after being sown at 30 ℃ for 120 d and the mean germination time (MGT) of seeds cultured in a shade (50% sunlight)nursery was 252 d. The most effective method of breaking dormancy was to remove the seed coat totally,which reduced the MGT to 13 d at 30 ℃. Germination was also promoted by partial removal of the seed coat (excising the hilum and exposing the radicle) and chemical scarification (immersion in 1% H2O2 for 1 d).Unscarified seeds take up water rapidly in the first 96 h, but water was absorbed by the outside seed coat,without penetrating through it. The moisture content (MC) of G. cowa seeds was high (50% in fresh weight)at shedding. The seeds could tolerate desiccation to some extent, until the MC reached approximately 40%;below that, the viability decreases rapidly and all seeds died at approximately 17% of MC. Seed viability decreased rapidly when seeds were chilled at 4 ℃; germination was 2% after storage for 1 week. Even stored at 10 ℃, seeds began to be damaged after 4 weeks. Seed storage for 1 yr revealed that in both dry (relative humidity (35 ± 5)%) and moist (wet sand) storage conditions, seed viability declined, but germination percentages for seeds stored under moist conditions are better than for seed stored under dry conditions.Because of their low tolerance to desiccation, marked chilling sensitivity and relatively short lifespan, G.cowa seeds should be classified into the tropical recalcitrant category. The ecological implications of dormant
9. Adaptation in Practice: How Managers of Nature Conservation Areas in Eastern England are Responding to Climate Change
Science.gov (United States)
Macgregor, Nicholas A.; van Dijk, Nikki
2014-10-01
Although good general principles for climate change adaptation in conservation have been developed, it is proving a challenge to translate them into more detailed recommendations for action. To improve our understanding of what adaptation might involve in practice, we investigated how the managers of conservation areas in eastern England are considering climate change. We used a written questionnaire and semi-structured interviews to collect information from managers of a range of different conservation areas. Topics investigated include the impacts of climate change perceived to be of the greatest importance; adaptation goals being set; management actions being carried out to achieve these goals; sources of information used; and perceived barriers to taking action. We identified major themes and issues that were apparent across the sites studied. Specifically, we found ways in which adaptation had been informed by past experience; different strategies relating to whether to accept or resist change; approaches for coping with more variable conditions; ways of taking a large-scale approach and managing sites as networks; some practical examples of aspects of adaptive management; and examples of the role that other sectors can play in both constraining and increasing a conservation area's capacity to adapt. We discuss the relevance of these findings to the growing discussion in conservation about identifying adaptation pathways for different conservation areas and a potential progression from a focus on resilience and incremental change to embracing "transformation." Though adaptation will be place-specific, we believe these findings provide useful lessons for future action in both England and other countries.
10. Distribution and Assessment of the Nature Conservational Status of the Nature Habitat 91Z0 „Moesian Silver Lime Forests” in SCI „Svishtovska Gora“ (BG0000576, Bulgaria
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Violeta G. Dimitrova
2015-06-01
Full Text Available The protected zones or Site of community importance (SCI are Natura 2000 areas which aim is to assure conditions for protection and survival of the most valuable and threatened species and habitats in Europe. Protected area BG0000576 „Svishtovska gora“ is a part of Natura 2000 network in Bulgaria. It is declared mainly for the protection of habitat 91Z0 „Moesian silver lime forests” which is 5.7% from its area. The habitat includes forests with domination or co-domination of silver lime (Tilia tomentosa Moench.. In Bulgaria the silver lime forests are distributed mainly in Danube Hilly Plane and Northeast Bulgaria (Ludogorie. The main threats for this type of habitat are illegal cuttings, after the restitution of the forests. The aim of the present investigation is to assess the status of the habitat and to make a map of its location in the zone. The methodology for mapping and assessment of the nature conservation status of the natural habitats developed under the project: „Mapping and determining of the natural conservational status of the nature habitats and species - phase I" were used in the present research. As a result of the study the habitat distribution map (112.36 ha was produced and its conservational status was assessed as unfavorable-unsatisfactory.
11. Strong signature of natural selection within an FHIT intron implicated in prostate cancer risk.
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Yan Ding
Full Text Available Previously, a candidate gene linkage approach on brother pairs affected with prostate cancer identified a locus of prostate cancer susceptibility at D3S1234 within the fragile histidine triad gene (FHIT, a tumor suppressor that induces apoptosis. Subsequent association tests on 16 SNPs spanning approximately 381 kb surrounding D3S1234 in Americans of European descent revealed significant evidence of association for a single SNP within intron 5 of FHIT. In the current study, re-sequencing and genotyping within a 28.5 kb region surrounding this SNP further delineated the association with prostate cancer risk to a 15 kb region. Multiple SNPs in sequences under evolutionary constraint within intron 5 of FHIT defined several related haplotypes with an increased risk of prostate cancer in European-Americans. Strong associations were detected for a risk haplotype defined by SNPs 138543, 142413, and 152494 in all cases (Pearson's chi(2 = 12.34, df 1, P = 0.00045 and for the homozygous risk haplotype defined by SNPs 144716, 142413, and 148444 in cases that shared 2 alleles identical by descent with their affected brothers (Pearson's chi(2 = 11.50, df 1, P = 0.00070. In addition to highly conserved sequences encompassing SNPs 148444 and 152413, population studies revealed strong signatures of natural selection for a 1 kb window covering the SNP 144716 in two human populations, the European American (pi = 0.0072, Tajima's D = 3.31, 14 SNPs and the Japanese (pi = 0.0049, Fay & Wu's H = 8.05, 14 SNPs, as well as in chimpanzees (Fay & Wu's H = 8.62, 12 SNPs. These results strongly support the involvement of the FHIT intronic region in an increased risk of prostate cancer.
12. Determinants of persistence and tolerance of carnivores on Namibian ranches: implications for conservation on Southern African private lands.
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Peter Andrew Lindsey
Full Text Available Changing land use patterns in southern Africa have potential to dramatically alter the prospects for carnivore conservation. Understanding these influences is essential for conservation planning. We interviewed 250 ranchers in Namibia to assess human tolerance towards and the distribution of large carnivores. Cheetahs (Acinonyx jubatus, leopards (Panthera pardus and brown hyaenas (Hyaena brunnea were widely distributed on Namibian farmlands, spotted hyaenas (Crocuta crocuta had a narrower distribution, and wild dogs (Lycaon pictus and lions (Panthera leo are largely limited to areas near source populations. Farmers were most tolerant of leopards and least tolerant of lions, wild dogs and spotted hyaenas. Several factors relating to land use correlated consistently with carnivore-presence and landowner tolerance. Carnivores were more commonly present and/or tolerated where; wildlife diversity and biomass were higher; income from wildlife was higher; income from livestock was lower; livestock biomass was lower; in conservancies; game fencing was absent; and financial losses from livestock depredation were lower. Efforts to create conditions whereby the costs associated with carnivores are lowest, and which confer financial value to them are likely to be the most effective means of promoting carnivore conservation. Such conditions are achieved where land owners pool land to create conservancies where livestock are replaced with wildlife (or where livestock husbandry is improved and where wildlife generates a significant proportion of ranch income. Additional measures, such as promoting improved livestock husbandry and educational outreach efforts may also help achieve coexistence with carnivores. Our findings provide insights into conditions more conducive to the persistence of and tolerance towards large carnivores might be increased on private (and even communal lands in Namibia, elsewhere in southern and East Africa and other parts of the world
13. Determinants of persistence and tolerance of carnivores on Namibian ranches: implications for conservation on Southern African private lands.
Science.gov (United States)
Lindsey, Peter Andrew; Havemann, Carl Peter; Lines, Robin; Palazy, Lucille; Price, Aaron Ernest; Retief, Tarryn Anne; Rhebergen, Tiemen; Van der Waal, Cornelis
2013-01-01
Changing land use patterns in southern Africa have potential to dramatically alter the prospects for carnivore conservation. Understanding these influences is essential for conservation planning. We interviewed 250 ranchers in Namibia to assess human tolerance towards and the distribution of large carnivores. Cheetahs (Acinonyx jubatus), leopards (Panthera pardus) and brown hyaenas (Hyaena brunnea) were widely distributed on Namibian farmlands, spotted hyaenas (Crocuta crocuta) had a narrower distribution, and wild dogs (Lycaon pictus) and lions (Panthera leo) are largely limited to areas near source populations. Farmers were most tolerant of leopards and least tolerant of lions, wild dogs and spotted hyaenas. Several factors relating to land use correlated consistently with carnivore-presence and landowner tolerance. Carnivores were more commonly present and/or tolerated where; wildlife diversity and biomass were higher; income from wildlife was higher; income from livestock was lower; livestock biomass was lower; in conservancies; game fencing was absent; and financial losses from livestock depredation were lower. Efforts to create conditions whereby the costs associated with carnivores are lowest, and which confer financial value to them are likely to be the most effective means of promoting carnivore conservation. Such conditions are achieved where land owners pool land to create conservancies where livestock are replaced with wildlife (or where livestock husbandry is improved) and where wildlife generates a significant proportion of ranch income. Additional measures, such as promoting improved livestock husbandry and educational outreach efforts may also help achieve coexistence with carnivores. Our findings provide insights into condition | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.35013049840927124, "perplexity": 7876.400895686516}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-09/segments/1518891814124.25/warc/CC-MAIN-20180222140814-20180222160814-00486.warc.gz"} |
http://crypto.stackexchange.com/questions/9901/why-is-the-p-521-elliptic-curve-not-in-suite-b-if-aes-256-is?answertab=oldest | # Why is the P-521 elliptic curve not in Suite B if AES-256 is?
In the NSA's document, "The Case for Elliptic Curve Cryptography", we have
+---------------+-------------------------+-----------------+
| Symmetric Key | RSA and Diffie-Hellman | Elliptic Curve |
| Size (bits) | Key Size (bits) | Key Size (bits) |
+---------------+-------------------------+-----------------+
| 80 | 1024 | 160 |
| 112 | 2048 | 224 |
| 128 | 3072 | 256 |
| 192 | 7680 | 384 |
| 256 | 15360 | 521 |
+---------------+-------------------------+-----------------+
Table 1: NIST Recommended Key Sizes
In NSA Suite B, we do have AES-256 (for TS), however the the ECC is limited to P-384, despite P-521 officially codified in NIST FIPS-186-4. This appears to introduce an entropic choke point if we're have a cryptographic "pipeline".
Example: If we're doing ECDH off P-384 keys to then AES-256 encrypt, we're effectively passing just 192 bits of keying entropy into the AES-256 engine.
Regarding NSA's omission of P-521, P-256 and P-384 will satisfy all of the U.S. Government's requirements so only these are included in Suite B. We don't have a requirement that warrants the inclusion of P-521.
I'm not able to piece these seemingly contradictory pieces of data, so I thought I'd ask other here. Why was P-521 excluded? Is it technical or non-technical? Additional info would be appreciated.
EDIT:
Not very directly related but I checked some empirical testing results. Seems compute times roughly double going from P-256 => P-386 => P-521, for almost any EC operation. Take for example signing a short (1200 bytes) message.
P-256: 8ms ( 64 byte signature)
P-384: 15ms ( 96 byte signature)
P-521: 30ms (132 byte signature)
It's not directly representative of the entropic bottleneck above, more aligned towards the "good enough" line of thought. But then, AES-192 should have also sufficed...
-
OK, so you found out that there is indeed a linear relation between computation time and ECC key size. This is a well known property of ECC and one of the reasons why ECC may be more future proof than e.g. RSA. Note that it is not possible for us to look into the mind of those generating the documents. The only thing I can tell is that e.g. the brainpool curves use a well defined set of domain parameters for a keysize of 512 bits. In general it is easier to handle data types that are a power of two and a multiple of 8. – Maarten Bodewes - owlstead Aug 24 '13 at 1:12
Since the rationale for the exclusion of P-521 and AES-192 is not explained, you can assume that either the curve is "too good" or that the cipher is "not good enough". The exclusion of SHA-512 implies a limit to 192-bit security for the standard, so AES-192 would be the logical choice. Its exclusion implies it is in someway not adequate for protecting TOP SECRET information at the given key length according the the NSA requirements for S3B.
The most logical answer is that S3B only requires a maximum of 192-bit security, and they are simply using AES-256 because of the increased round count over AES-192 or the difference in key schedule alignment. It has been argued by some over the years that AES has too low a round count for its given key lengths, so this makes sense from a security perspective. AES-256 only has a 40% increase in rounds for a 100% increase in keylength over AES-128, if I was writing the standard I may have made the same decision to skip AES-192.
S3A algorithms are classified, but most likely require 256-bit security and up, with higher standards for long term protection against cryptanalysis by well funded attackers (100+ years of security from China and Russia), and as such may skip AES all together and go to either variants with different round counts and key schedules, or use purpose built algorithms that do not have the same speed/security tradeoff that AES has.
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The real question isn't "Why doesn't Suite B use P-521?" It is, "Why doesn't Suite B use AES-192?" NSA were only interested in 192-bit security for Suite B, but they chose to use AES-256 because AES-192 wasn't widely supported.
"In fact we had wanted to use AES -128 and AES-192, but a quick survey of AES implementations (hardware centric, I believe) showed that there were very few implemented AES-192, whence the decision to go with AES-128 and AES-256 in Suite B, paired with P256 and P384. All of the crypt purists grumbled endlessly about the mismatch betwixt AES-256 and P384."
-- Kevin M. Igoe, NSA
(I am choosing to take his explanation at face value, but you never know with intelligence agencies.)
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https://www.physicsforums.com/threads/power-series-solution-to-a-diff-eq.223944/ | Power Series Solution to a Diff EQ
1. Mar 24, 2008
[SOLVED] !!!Power Series Solution to a Diff EQ!!!
1. The problem statement, all variables and given/known data
Find the first 5 term of a Power series solution of
$$y'+2xy=0$$ (1)
Missed this class, so please bear with my attempt here.
3. The attempt at a solution
Assuming that y takes the form
$$y=\sum_{n=0}^{\infty}c_nx^n$$
Then (1) can be written:
$$\sum_{n=1}^{\infty}nc_nx^{n-1}+2x\sum_{n=0}^{\infty}c_nx^n=0$$
Re-written 'in phase' and with the same indices (in terms of k):
$$c_1+\sum_{k=1}^{\infty}(k+1)c_{k+1}x^k+\sum_{k=1}^{\infty}2c_{k-1}x^k=0$$
$$\Rightarrow c_1+\sum_{k=1}^{\infty}[(k+1)c_{k+1}+2c_{k-1}]x^k=0$$
Now invoking the identity property, I can say that all coefficients of powers of x are equal to zero (including $c_1*x^0$)
So I can write:
$c_1=0$ and
$$c_{k+1}=-\frac{2c_{k-1}}{k+1}$$
Now I am stuck (I know I am almost there though!)
Should I just start plugging in numbers for k=1,2,3,4,5 ? Will this generate enough 'recursiveness' to solve for the 1st five terms?
Is that the correct approach?
Thanks!!
2. Mar 24, 2008
Don't worry guys, I got it. And for those who might make future use of this thread, my approach was correct. Solving
$$c_{k+1}=-\frac{2c_{k-1}}{k+1}$$
For k=1,2....,9 generates enough coefficients to write out the first five nonzero terms of the solution by plugging them back into
$$y=\sum_{n=0}^{\infty}c_nx^n$$
Last edited: Mar 24, 2008
3. Mar 24, 2008
Kreizhn
I think you need one more initial condition on your series (example $y(0)=x_0$). You need to define $c_0$ (or you can just leave $c_0$ as the 'integration' constant of the ODE). However, the recursion formula becomes pretty obvious once you have that. If you can't see it right away, try plugging in a few values. Since $c_1=0$ what can we say about all the odd labelled coefficients? You should get something that looks like the series of an exponential function. In fact, the series will have a closed form solution if you can see how your answer relates to the exponential series. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9376910328865051, "perplexity": 462.220984267781}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-44/segments/1476988720475.79/warc/CC-MAIN-20161020183840-00012-ip-10-171-6-4.ec2.internal.warc.gz"} |
http://www.cs.cmu.edu/afs/cs/project/jair/pub/volume10/jaakkola99a-html/footnode.html | ...model.1
The acronym QMR-DT'' that we use in this paper refers to the decision-theoretic'' reformulation of the QMR by Shwe, et al. (1991). Shwe, et al. replaced the heuristic representation employed in the original QMR model (Miller, Fasarie, & Myers, 1986) by a probabilistic representation.
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...QMR-DT.2
D'Ambrosio (1994) reports mixed'' results using incremental SPI on the QMR-DT, for a somewhat more difficult set of cases than Heckerman (1989) and Henrion (1991), but still with a restricted number of positive findings.
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...decoupled.3
Jensen's inequality, which states that $f(a + \sum_j q_j x_j) \geq \sum_j q_j f(a + x_j)$, for concave $f$, where $\sum q_j = 1$, and $0 \leq q_j \leq 1$, is a simple consequence of Eq. (8), where $x$ is taken to be $a + \sum_j q_j x_j$.
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...exactly.4
Given that a significant fraction of the positive findings are being treated exactly in these simulations, one may wonder what if any additional accuracy is due to the variational transformations. We address this concern later in this section and demonstrate that the variational transformations are in fact responsible for a significant portion of the accuracy in these cases.
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...algorithm.5
The initialization method proved to have little effect on the inference results.
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...inference.6
We also investigated Gibbs sampling (Pearl, 1988). The results from Gibbs sampling were not as good as the results from likelihood-weighted sampling, and we report only the latter results in the remainder of the paper.
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...method.7
It should be noted that this is a conservative comparison, because the partially-exact method in fact benefits from the variational transformation-the set of exactly treated positive findings is selected on the basis of the accuracy of the variational transformations, and these accuracies correlate with the diagnostic relevance of the findings.
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Michael Jordan
Sun May 9 16:22:01 PDT 1999 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9405215978622437, "perplexity": 893.6808230539567}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-05/segments/1516084887832.51/warc/CC-MAIN-20180119065719-20180119085719-00482.warc.gz"} |
https://physics.stackexchange.com/questions/250568/lattice-parameters-and-basis-vectors-of-crystal-lattice-structures | # Lattice parameters and basis vectors of crystal lattice structures
Does someone know where I can find lattice parameters and basis vectors of crystal lattice structures (Strukturbericht Designation) for different materials?
In particular I am searching the lattice parameters and the atomic basis of the Strukturbericht Designation B1, B2, B16, B27, and B33 of PbSe (lead selenide).
I already found this page, https://homepage.univie.ac.at/michael.leitner/lattice/struk/btype.html, however, there the lattice parameters and the atomic basis is only given for a prototype of a structure.
Isn't there a general reference?
• I see three PbSe entries in Crystallography Open Database, but all in the same spacegroup: 1537678, 9011359, 9011360. I could overlook something, I'm not really familiar with COD. – marcin Apr 19 '16 at 8:34
• And Googling 'crystal structure PbSe' pulls up various suggestions of papers. A good science database search yields many others. One to start with would be S V Streltsov1, A Yu Manakov2, A P Vokhmyanin1, S V Ovsyannikov1 and V V Shchennikov1 Published 24 August 2009 • IOP Publishing Ltd Journal of Physics: Condensed Matter, Volume 21, Number 38 and references therein. – Jon Custer Apr 19 '16 at 13:38
• Thank you very much. I also tried it this way but in most of the papers they only write the lattice parameters but not the atom positions. That was a bit frustrating so I thought there must be another data base where the people get the positions from... – thyme Apr 19 '16 at 14:13
• The cif files in COD have positions, in this case Pb 0 0 0 and Se 0.5 0.5 0.5. Equivalent positions are not listed; they are implied by the space group. If you open such a CIF file in a viewer that understands this format you will see all atoms. – marcin Apr 20 '16 at 10:29 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7376814484596252, "perplexity": 1534.3988993522876}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-35/segments/1566027314904.26/warc/CC-MAIN-20190819180710-20190819202710-00017.warc.gz"} |
https://www.physicsforums.com/threads/bug-physics.176750/ | # Bug physics.
1. Jul 12, 2007
### Demonsthenes
1. The problem statement, all variables and given/known data
A bug of mass m is stuck to a point on the rim of a rolling wheel (of radius r)... which traces out a path called a cycloid. The position vector of the point (bug) is given by:
r(theta) = r(theta - sin(theta))i + r(1 - cos(theta))j
For a wheel rolling with constant angular spped...
2. Relevant equations
A) Determine the velocity vector v = vxi + vyj.
B) Determine the acceleration vector a =axi + ayj
C) Verify the magnitude of the acceleration vector is given by a = r(greek w)^2
3. The attempt at a solution
The derivatives i took for each vector looked very incorrect.
1. The problem statement, all variables and given/known data
2. Relevant equations
3. The attempt at a solution
Can you offer guidance or do you also need help?
Draft saved Draft deleted
Similar Discussions: Bug physics. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9740546941757202, "perplexity": 1829.8137173739071}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-43/segments/1508187824537.24/warc/CC-MAIN-20171021005202-20171021025202-00405.warc.gz"} |
http://math.stackexchange.com/questions/283308/point-of-discontinuity | # Point of discontinuity
I have a function: $$f(x) = x$$ Defined over the domain $\mathbb{R} \backslash 0$. Is it correct to say that:
The function is continuous, but it has a point of discontinuity at $x=0$?
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No it doesn't. Why would $f(x)=x$ have a discontinuity? – nbubis Jan 21 '13 at 7:56
I can't imagine a better example, therefore I said there's f(x)=x with the domain R without 0. – TomDavies92 Jan 21 '13 at 7:57
I think it is a valid a good question to clarify subtleties regarding fundamental definitions. The choice of function is very good since it concentrates on the issue at hand: the question whether 'not defined at a point' means 'not continuous there'. – Ittay Weiss Jan 21 '13 at 8:04
@TomDavies92 - Edited the English, I think it makes more sense now. – nbubis Jan 21 '13 at 8:12
The function is continuous for all points where it is defined, which according to you is the set $\mathbb R - \{0\}$. It has no points of discontinuity. A point $x$ is a point of discontinuity for a function $f:D\to \mathbb R$ if the function is defined at that point but its value there is not the same as the limit. When $f$ is not defined at $x$ at all then $x$ can't be considered a point of discontinuity. Think of it this way: the function $f(x)=x^2$, defined on all of the real numbers, is not defined for $x$="the moon". Does it mean that $f$ is discontinuous at the moon?
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Ittay Weiss said "When $f$ is not defined at $x$ at all then $x$ can't be considered a point of discontinuity." What about $f(x) = 1/x$? $0$ is not defined at $f$, nevertheless, as long as I know $0$ is considered a point of discontinuity for the function $f(x) = 1/x$. It is enough for the function $f$ to be defined on some neighborhood of $x_0$ even though it is not defined at $x_0$. I think this point is a point of discontinuity since $\lim_{x\to 0+} = \lim_{x\to 0-} = 0$, but $f(0)\neq 0$ (undefined by definition). – fade2black Aug 20 '13 at 22:34
It is true that $f(x)=1/x$ is not continuous at $x=0,$ since it isn't defined there. However, this does not mean that $f$ has a discontinuity at $x=0.$ See here, especially: "The term removable discontinuity is sometimes used by abuse of terminology...." – Cameron Buie Aug 21 '13 at 4:51
Then what about the example $1/x$, where $0$ is not in the domain of $f$? My text book on calculus says that the point 0 is a non-removable point of discontinuity (Calculus, 9th Ed., Ron Larson, pg. 71, Example 1 (a), function $f(x)=1/x$). – fade2black Aug 21 '13 at 8:15
@fade2black: Again, that is not a discontinuity. It is what is known as a pole. Many textbooks would call that a discontinuity, but again, this is an abuse of terminology. Continuity and discontinuity are defined only for points of the function's domain. I suspect that your textbook did not give a precise definition of what continuity at a point means, because otherwise, they couldn't claim that $0$ was a point of discontinuity of $f(x)=1/x$. – Cameron Buie Aug 21 '13 at 13:56
No, the continuity or discontinuity of a function at a point is only defined if the point is in the domain. The function is continuous at every point of its domain, which was stipulated to be $\mathbb R\setminus \{0\}$. It is not defined at $0$.
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What about limit points? I heared, that the point of discontinuity is also a limit point, that does not belong to the domain. Is it true? – TomDavies92 Jan 21 '13 at 7:58
I do not understand the question. – Jonas Meyer Jan 21 '13 at 8:01
@TomDavies92: It is depend on what kind of discontinuty you faced at that point. – Babak S. Jan 21 '13 at 8:02
@TomDavies92: But perhaps you are thinking about something like the following. If $f:\mathbb R\setminus\{0\}\to\mathbb R$ is a function, then when is it possible to extend $f$ by defining a value $f(0)$ in such a way to make the extended function continuous at $0$? This could be answered by checking whether or not $\lim\limits_{x\to 0}f(x)$ exists. – Jonas Meyer Jan 21 '13 at 8:04
If $x=0$ is not part of the domain of the function, there is no sense in talking about the properties of the function at that point - continuity or anything else.
It happens that the domain on which this function is defined is a part of a larger domain - it is a fundamental issue in mathematics to identify the possibility of extending functions to such larger domains in "good" ways - either preserving useful properties like continuity, or acquiring new ones - like connectedness, compactness or roots to specific equations.
Your $f$ could be extended to $\mathbb R$ by defining $f(0)=\pi$. If you want to preserve continuity, however, you need to define $f(0)=0$.
You might consider the function $g(x)$ defined on the same domain with $g(x)=-x$ when $x$ is negative, and $g(x)=x$ when $x$ is positive. Defining $g(0) = 0$ keeps $g$ continuous, but it is no longer differentiable over the whole domain of definition. Sometimes there is a trade-off between the properties you want and the domain you choose.
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First, I agree with most other answers: What you say about your $f$ is not totally right but $f$ is continuous where is defined.
I would like to add, that probably some confusion is caused by the fact that there is an obvious extension to a superset of its domain of definition. (Here, set $f(0)=0$, obviously.)
Indeed, the problem if a continuous function defined on some set has a continuous extension to a larger set is very important in some places of mathematics (e.g. if a continuous linear operator on a Banach space can be extended to a larger Banach space in which the former one is embedded...). Another example is the theorem that a continuous function defined on a dense set of a metric space has a continuous extension to the whole space.
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https://www.gradesaver.com/civil-disobedience/q-and-a/how-do-the-ideas-expressed-in-lines-88-96-help-to-qualify-or-clarify-some-of-thoreaus-ideas-323102 | # How do the ideas expressed in lines 88-96 help to qualify or clarify some of thoreau's ideas?
lines 88-96
" why does it always crucify christ, and excommunicate copernicus and luter , and pronounce washington and franklin rebels?...
if the unjusice is part of the necessary friction of the machine of goverment, let it go, let it go: perchance it will wear smooth, the machine will wear out . ifinjustice has a spring or a pulley or a rope or a crank , exclusively for itself, then perhaps you may consider whether the remedy will not be worse than evil: but if it so much a nature tat it requires you to be the agent of the injustiice to another , then, i sa break the law. let your life be a counter-friction to stop the machine. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8202595710754395, "perplexity": 2503.0387062749564}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-34/segments/1534221209216.31/warc/CC-MAIN-20180814170309-20180814190309-00243.warc.gz"} |
https://christopherdanielson.wordpress.com/2014/04/28/wiggins-questions-3/ | # Wiggins questions #3
## Question 3
### You are told to “invert and multiply” to solve division problems with fractions. But why does it work? Prove it.
Oh dear. If anyone on the Internet has had more to say about dividing fractions than I have, I am unaware of who that is. (And, for the record, I would like to buy that person an adult beverage!)
Unlike the division by zero stuff from question 1, this question is better tackled with informal notions than with formalities. The formalities leave one feeling cold and empty, for they don’t answer the conceptual why. The formalities will invoke the associative property of multiplication, the definition of reciprocal, inverse and the multiplicative identity, et cetera.
The conceptual why—for many of us—lies in thinking about fractions as operators, and in thinking about a particular meaning of division.
### 1. A meaning of division
There are two meanings for division: partitive (or sharing) and quotative (or measuring). The partitive meaning is the most common one we think of when we do whole number division. I have 12 cookies to share equally among 3 people. How many cookies does each person get? We know the number of groups (3 in this example) and we need to find the size of each group.
I can mow 4 lawns with $\frac{2}{3}$ of a tank of gas in my lawnmower is a partitive division problem because I know what $\frac{2}{3}$ of a tank can do, and I want to find what a whole tank can do. So performing the division $4\div \frac{2}{3}$ will answer the question.
### 2. Fractions as operators
When I multiply by a fraction, I am making things larger (if the fraction is greater than 1), or smaller (if the fraction is less than 1, but still positive).
Scaling from (say) 5 to 4 requires multiplying 5 by $\frac{4}{5}$. Scaling from 4 to 5 requires multiplying by $\frac{5}{4}$. This relationship always holds—reverse the order of scaling and you need to multiply by the reciprocal.
### putting it all together
Back to the lawnmower. There is some number of lawns I can mow with a full tank of gas in my lawnmower. Whatever that number is, it was scaled by $\frac{2}{3}$ to get 4 lawns. Now we need to scale back to that number (whatever it is) in order to know the number of lawns I can mow with a full tank.
So I need to scale 4 up by $\frac{3}{2}$.
Now we have two solutions to the same problem. The first solution involved division. The second solution involved multiplication. They are both correct so they must have the same value. Therefore,
$4\div \frac{2}{3} = 4 \cdot \frac{3}{2}$
There was nothing special about the numbers chosen here, so the same argument applies to all positive values.
$A\div\frac{b}{c}=A\cdot\frac{c}{b}$
We have to be careful about zero. Negative numbers behave the same way as positive numbers in this case, since the associative and commutative properties of multiplication will let us isolate any values of $-1$ and treat everything else as a positive number.
Please note that you do not need to invert and multiply to solve fraction division problems. You can use common denominators, then divide just the resulting numerators. You can use common numerators, then use the reciprocal of the resulting denominators. Or you can just divide across as you do when you multiply fractions. The origins of the strong preference for invert-and-multiply are unclear.
### 7 responses to “Wiggins questions #3”
Christopher, my issue with this defense of the invert and multiply algorithm is not consistent with the way we think of c x d, where c is the multiplier and d is the multiplicand. So, when we multiply a number c (number to be replicated) by a number d (number of groups or replications), we represent that symbolically by c x d (c groups of d) and not the other way around. I agree that we “scale 4 up by 3/2,” but that is interpreted symbolically as 3/2 x 4. In this case, 4 x 3/2 doesn’t have a contextual interpretation that makes sense.
Maybe, at the level that students are doing multiplication and division of fractions, they can abandon the (more) concrete interpretation of multiplication for the abstract, but I tend toward being more of a stickler in this case, because there is a bridge that we can make between the concrete interpretation and abstract symbols (common denominator algorithm or this on with the multiplier in the appropriate position). I also think that, despite the CC’s focus on standard algorithms, a defense of the invert and multiply algorithm can be taken as a free ticket to Same/change/flip-ville. Although, sadly, I don’t think the citizens there are really reading your blog.
2. Christopher
Wait!
You see this as a defense of the standard algorithm for fraction division as a curricular topic, Adam? That was not its purpose at all. I am just answering the question here, which is a reasonable one: Is there a conceptual way to think about this algorithm? I say yes. As you rightly point out, this answer may not be appropriate for all audiences.
But the algorithm is not at fault. There are no bad correct algorithms.
There are, however, algorithms that are more likely to support the thinking of a typical student. Common denominator fraction division is more likely to support the thinking of the average 5th-7th grader. And it is more likely to be in the capacity of the average elementary teacher to teach conceptually. We are agreed on that.
I think you may be ignoring what I think is the crux of my argument – the order of 4 and 3/2 in the operation cannot be overlooked, if conceptual is the goal, despite the level of the student. 4 / (2/3) is not equal to 3/2 x 4, at the concrete level.
I didn’t say this is a bad algorithm, but I do think that there are certainly better ones, given the historical treatment of it (“Ours is not to reason why…,” Keep/Change/Flip, etc.). I also think that, much like the standard long division algorithm, this algorithm is unproductive. Kids memorize it without knowing why it works…and then forget it, like the division algorithm. Maybe I would have rather seen you answer the question with something along the lines of “yes, but here’s a different algorithm that grows out of a concrete representation of the operation” or something like that.
4. Maybe it’s a bit late, but I have just found your other blog (this one!).
lawnmower, and other similar problems.
Simple, common sense method:
4 lawns with 2/3 of a tank, so 2 lawns with one third of a tank
so 6 lawns with a full tank.
if the kids are pushed into converting the problem into an immediate calculation, and not encouraged to “get the result somehow” then the path is smoothed for the rest of the math difficulties lying ahead.
If the kids cannot see step 1 above then they are definitely not ready for fractions.
My position is that from the outset fractions are numbers, and invented/used to enhance measurement.
I will stop here!!!!!
5. Late
If it’s known that 4 lawns are cut with 2/3 of gas tank, then…
Assuming that the lawnmower engine works, at full power, across all fuel states of the gas tank, except when empty.
One third of gas, would theoretically, yield only 2 lawns cut. It makes sense, with half the gas (comparing 1/3 to 2/3), you would only cut half the grass. 2/3 gas must cut double the amount of grass, compared to 1/3 gas.
Each third of gas, is individually, the same amount of litres, of course. Each third is the same size, of course. Otherwise it wouldn’t be called a third of some original amount. (obviously). Each third of gas therefore cuts same amount of grass, individually.
When you know that one third is something, then you simply add three thirds together to get one whole. (1/3) + (1/3) + (1/3) = 3/3, otherwise known as one whole.
2+2+2 = 6 lawns cut, with a fully operational 3/3 gas tank.
To me this sounds like some blue collar math logic, but it works well enough in this case.
6. sassyaggie
Like a Number Talk, I’m seeing from the comments different ways of looking at the same problem. Could it be possible of doing that even with using the same algorithm? What would you say is the big idea? | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 10, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8707944750785828, "perplexity": 703.050696350801}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-22/segments/1495463608954.74/warc/CC-MAIN-20170527133144-20170527153144-00500.warc.gz"} |
https://socratic.org/questions/59e341137c0149198d7e042c | Chemistry
Topics
# Question e042c
Oct 20, 2017
Here's what I got.
#### Explanation:
Start by picking a sample of this $\text{20% v/v}$ ethanol solution. To make the calculations easier, let's say that this sample has a volume of $\text{100 mL}$.
The solution is said to be $\text{20% v/v}$ ethanol, which implies that it contains $\text{20 mL}$ of ethanol, the solute, for every $\text{100 mL}$ of the solution.
Use the density of the solution to find its mass.
100 color(red)(cancel(color(black)("mL solution"))) * "0.9 g solution"/(1color(red)(cancel(color(black)("mL solution")))) = "90 g solution"
Next, usee the density of ethanol to find the mass of the solute.
20 color(red)(cancel(color(black)("mL ethanol"))) * "0.75 g ethanol"/(1color(red)(cancel(color(black)("mL ethanol")))) = "15 g ethanol"
Now, in order to find the solution's percent concentration by mass, $\text{m/m %}$, you need to figure out the mass of ethanol present in $\text{100 g}$ of this solution.
Since you already know how much ethanol you have in $\text{90 g}$ of the solution, you can say that $\text{100 g}$ will contain
100 color(red)(cancel(color(black)("g solution"))) * "15 g ethanol"/(90color(red)(cancel(color(black)("g solution")))) = "16.667 g ethanol"#
This means that the percent concentration by mass is equal to
$\textcolor{\mathrm{da} r k g r e e n}{\underline{\textcolor{b l a c k}{\text{% m/m = 17% ethanol}}}}$
I'll leave the answer rounded to two sig figs, but keep in mind that you should round it to one significant figure, the number of sig figs you have for the percent concentration by volume.
##### Impact of this question
713 views around the world | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 13, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8702424168586731, "perplexity": 1849.3250667516936}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-40/segments/1600402123173.74/warc/CC-MAIN-20200930075754-20200930105754-00749.warc.gz"} |
https://www.physicsforums.com/threads/odd-equation-relating-to-springs-and-shm.73285/ | # Odd equation relating to springs and SHM
1. Apr 26, 2005
### K - Prime
Well im working on a lab report for 12th grade physics and my teacher has decided to throw a cuve ball at us. The lab is designed to determine the value of the force constant of a spring by measuring the number of oscillations a certain weight makes when on the end of the spring. To find k was easy, i just used the equation T = 2pi (m/k)^1/2. Heres the part i dont get...he asked us to find the value of m/3 using a graph of T^2 vs m (mass on spring) and gave us the equation T = 2pi [(M + m/3)/k]^1/2. All i can say is WHAT!?
2. Apr 27, 2005
### whozum
Well the point ofthe lab wasto find the spring constant, and you modeled that already by graphing it, correct? (If not, do so). Now since you know the trend of period vs mass, you should be able to predict mass ifyou measure a certain period. Notice that the only difference between the firstequation you gave and the last one (which you didnt recognize) is that the last one has a different value for mass.
$$T = 2\pi\sqrt{\frac{m}{k}}$$
He gives:
$$T = 2\pi\sqrt{\frac{M+m/3}{k}}$$
If you say the mass is $n$, then $n = M + m/3$ and the second equation becmoes
$$T = 2\pi\sqrt{\frac{n}{k}}$$, which is analogous to the first equation. So the numerator under the square root is simply a new total mass, nothing to be surprised about. Using the plot you derived in your original lab, find a way to calculate the new mass.
This process isnt necessary to do the problem, but hopefully it helps you see what is going on more clearly.
3. Apr 27, 2005
### K - Prime
ahh i see, that helps alot! thx!
Similar Discussions: Odd equation relating to springs and SHM | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7980066537857056, "perplexity": 705.3320808419855}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-30/segments/1500549423901.32/warc/CC-MAIN-20170722042522-20170722062522-00365.warc.gz"} |
https://crypto.stackexchange.com/tags/perfect-secrecy/new | # Tag Info
How many non-trivial*, interesting perfect secrecy systems are there other than the one-time-pad? Infinitely many. Let $\mathbb G$ be a group (written multiplicatively). Then $\operatorname{KeyGen}(1^n)=k\stackrel{\$}{\gets}\mathbb G^n$, that is the key is a vector of$n$independently random group elements.$\operatorname{Enc}(k,m):\mathbb G^n\times \... | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9858105778694153, "perplexity": 7209.984977641445}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-24/segments/1590347410535.45/warc/CC-MAIN-20200530231809-20200531021809-00563.warc.gz"} |
http://link.springer.com/chapter/10.1007%2F3-540-36178-2_17 | Chapter
Advances in Cryptology — ASIACRYPT 2002
Volume 2501 of the series Lecture Notes in Computer Science pp 267-287
Date:
# Cryptanalysis of Block Ciphers with Overdefined Systems of Equations
• Nicolas T. CourtoisAffiliated withCP8 Crypto Lab, SchlumbergerSema
• , Josef PieprzykAffiliated withCenter for Advanced Computing - Algorithms and Cryptography, Department of Computing, Macquarie University
## Abstract
Several recently proposed ciphers, for example Rijndael and Serpent, are built with layers of small S-boxes interconnected by linear key-dependent layers. Their security relies on the fact, that the classical methods of cryptanalysis (e.g. linear or differential attacks) are based on probabilistic characteristics, which makes their security grow exponentially with the number of rounds N r r.
In this paper we study the security of such ciphers under an additional hypothesis: the S-box can be described by an overdefined system of algebraic equations (true with probability 1). We show that this is true for both Serpent (due to a small size of S-boxes) and Rijndael (due to unexpected algebraic properties). We study general methods known for solving overdefined systems of equations, such as XL from Eurocrypt’00, and show their inefficiency. Then we introduce a new method called XSL that uses the sparsity of the equations and their specific structure.
The XSL attack uses only relations true with probability 1, and thus the security does not have to grow exponentially in the number of rounds. XSL has a parameter P, and from our estimations is seems that P should be a constant or grow very slowly with the number of rounds. The XSL attack would then be polynomial (or subexponential) in N r> , with a huge constant that is double-exponential in the size of the S-box. The exact complexity of such attacks is not known due to the redundant equations. Though the presented version of the XSL attack always gives always more than the exhaustive search for Rijndael, it seems to (marginally) break 256-bit Serpent. We suggest a new criterion for design of S-boxes in block ciphers: they should not be describable by a system of polynomial equations that is too small or too overdefined.
### Key Words
Block ciphers AES Rijndael Square Serpent Camellia multivariate quadratic equations MQ problem overdefined systems of multivariate equations XL algorithm Gröbner bases sparse multivariate polynomials Multivariate Cryptanalysis | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8421176671981812, "perplexity": 1522.72503529583}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-40/segments/1474738661962.7/warc/CC-MAIN-20160924173741-00000-ip-10-143-35-109.ec2.internal.warc.gz"} |
http://math.stackexchange.com/questions/252434/pigeonhole-principle-on-graphs | # Pigeonhole Principle on Graphs
I just have a last minute question for my combinatorics final (which is in one hour!!).
My prof particularly told me to study the following question and I'm pretty sure it involves the pigeonhole principle but I can't remember how it applies. Can anyone help me out?
Prove that for each $n \in \mathbb{Z}^+$ There exists a loop-free connected undirected graph $G=(V,E)$, where $|V|=2n$ and which has two vertices of degree $i$ for every $1 \leq i \leq n$.
Any help is greatly, greatly appreciated!
-
Doesn't look like a pigeonhole principal problem to me. – Thomas Andrews Dec 6 '12 at 17:36
Hm. Maybe I'm confusing it with another one. I just thought I remembered it being answered as a pigeonhole principle question. I'll try to tackle it differently – connorbode Dec 6 '12 at 17:38
has at leat 2 vertices or exactly two vertices ? – Amr Dec 6 '12 at 17:42
@somekindarukus This is a sort of converse to the well-known fact that in every simple graph there are two vertices with the same degree. This latter problem is a very standard application of pigeonhole. – Erick Wong Dec 6 '12 at 17:43
@Amr "Exactly" or "At least" are the same here. There are $2n$ nodes. If, for each $i$, there are at least two nodes with degree $i$, then, for each $i$, there are exactly two nodes with degree $i$. – Thomas Andrews Dec 6 '12 at 17:51
Suppose that you have a bipartite graph $G_n$ with vertex classes $V_0$ and $V_1$, each containing $n$ vertices, one of each degree from $1$ through $n$. Add an isolated vertex to each part to get a bipartite graph $H_n$, each of whose parts contains one vertex of degree $k$ for $k=0,\dots,n$. Now add one more vertex to each part, connecting it by an edge to each vertex in the other part. The resulting graph $G_{n+2}$ will be bipartite, and each part will contain one vertex of degree $k$ for $k=1,\dots,n+2$.
@Thomas: That’s easy: just do it. Take vertices $1,2,3,1',2',3'$ with edges $\{3,1'\},\{3,2'\},\{3,3'\}$, $\{2,3'\},\{2,2'\}$, and $\{1,3'\}$. – Brian M. Scott Dec 6 '12 at 18:10
I just want to note that the graphs need not necessarily be bipartite. You can do a one step induction from $n$ to $n+1$. If $G_n$ is divided into two vertex classes, $V_0$ and $V_1$, of size $n$, each containing one vertex of degree $k$ for $1\leq k \leq n$, then we simply add two isolated vertices, $v_0$ and $v_1$, and add edges from $v_i$ to the $\lfloor \frac{n+1}{2} \rfloor$ vertices of largest degree in $V_i$, $i=1,2$. Then, if $n$ is even, add the edge ${v_0,v_1}$. Note that for $n \geq 4$, $G_n$ is NOT bipartite. – Kevin Halasz Jan 18 '13 at 22:53 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8626657724380493, "perplexity": 155.74973012853226}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-18/segments/1429246644200.21/warc/CC-MAIN-20150417045724-00306-ip-10-235-10-82.ec2.internal.warc.gz"} |
http://nrich.maths.org/7097 | ### Circles Ad Infinitum
A circle is inscribed in an equilateral triangle. Smaller circles touch it and the sides of the triangle, the process continuing indefinitely. What is the sum of the areas of all the circles?
### Climbing Powers
$2\wedge 3\wedge 4$ could be $(2^3)^4$ or $2^{(3^4)}$. Does it make any difference? For both definitions, which is bigger: $r\wedge r\wedge r\wedge r\dots$ where the powers of $r$ go on for ever, or $(r^r)^r$, where $r$ is $\sqrt{2}$?
A quadrilateral changes shape with the edge lengths constant. Show the scalar product of the diagonals is constant. If the diagonals are perpendicular in one position are they always perpendicular?
# Weekly Challenge 6: AP Train
##### Stage: 5 Short Challenge Level:
A particular list of $N$ consecutive integers starts with $1111$ as follows:
$$1111, 1112, 1113, \dots, 1111 + N-1$$
The entire list is shifted $D$ places along the number line and the first number then excluded, leaving a list of $N-1$ larger consecutive numbers as follows:
$$1112+D, 1113+D, \dots, 1111 + N -1+ D$$
In each list the sum of the integers is the same.
What are the possibilities for $N$ and $D$?
Extension: Maybe you wish to try to create a similar problem to this one?
Did you know ... ?
Progressions of integers occur remarkably frequently in mathematics in applications from quantum mechanics to number theory and they have many beautiful properties. Even Carl Gauss, possibly the greatest mathematician of all time, fondly recalled his first encounter with sums of consecutive natural numbers, when he noticed that the sum of the first $100$ whole numbers equalled $50$ lots of $101$. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4933786690235138, "perplexity": 535.5992424467911}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-50/segments/1480698542695.22/warc/CC-MAIN-20161202170902-00186-ip-10-31-129-80.ec2.internal.warc.gz"} |
https://kyushu-u.pure.elsevier.com/en/publications/a-synthetic-solution-for-identification-and-extraction-of-the-eff | # A Synthetic Solution for Identification and Extraction of the Effective Microseismic Wave Component Using Decomposition on Time, Frequency, and Wavelet Coefficient Domains
Mingwei Zhang, Qingbin Meng, Shengdong Liu, Hideki Shimada
Research output: Contribution to journalArticlepeer-review
## Abstract
To reduce noise components from original microseismic waves, a comprehensive fine signal processing approach using the integrated decomposition analysis of the wave duration, frequency spectrum, and wavelet coefficient domain was developed and implemented. Distribution regularities of the wave component and redundant noise on the frequency spectrum and the wavelet coefficient domain were first expounded. The frequency threshold and wavelet coefficient threshold were determined for the identification and extraction of the effective wave component. The frequency components between the reconstructed microseismic wave and the original measuring signal were compared. The noise elimination effect via the scale-changed domain decomposition was evaluated. Interaction between the frequency threshold and the wavelet coefficient threshold in the time domain was discussed. The findings reveal that tri-domain decomposition analysis achieves the precise identification and extraction of the effective microseismic wave component and improves the reliability of waves by eliminating the redundant noise. The frequency threshold and the wavelet coefficient threshold on a specific time window are two critical parameters that determine the degree of precision for the identification of the extracted wave component. This research involves development of the proposed integrated domain decomposition method and provides a diverse view on the fine processing of the microseismic signal.
Original language English 3875170 Shock and Vibration 2017 https://doi.org/10.1155/2017/3875170 Published - 2017
## All Science Journal Classification (ASJC) codes
• Civil and Structural Engineering
• Condensed Matter Physics
• Geotechnical Engineering and Engineering Geology
• Mechanics of Materials
• Mechanical Engineering
## Fingerprint
Dive into the research topics of 'A Synthetic Solution for Identification and Extraction of the Effective Microseismic Wave Component Using Decomposition on Time, Frequency, and Wavelet Coefficient Domains'. Together they form a unique fingerprint. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9023885130882263, "perplexity": 3067.2138268481394}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446710953.78/warc/CC-MAIN-20221204004054-20221204034054-00716.warc.gz"} |
https://chemistry.stackexchange.com/questions/70678/do-li4-or-li8-molecules-exist | # Do Li4 or Li8 molecules exist?
I've read that alkali metals form ionic bonds; $\ce{Li}$ is an exception which majorly forms covalent bonds. Wikipedia says dilithium exists. This makes me wonder why $\ce{Li_8}$ doesn't exist. It seems having all 8 electrons shared produces a low energy state (because the valence shell in each of the 8 atoms will be completely filled) ?
Yes, they do exist and were characterised spectroscopically, see here (and there is a note on similar clusters for sodium):
Blanc, J.; Bonačić‐Koutecký, V.; Broyer, M.; Chevaleyre, J.; Dugourd, P.; Koutecký, J.; Scheuch, C.; Wolf, J. P.; Wöste, L. Evolution of the electronic structure of lithium clusters between four and eight atoms. J. Chem. Phys. 1992, 96 (3), 1793–1809. DOI: 10.1063/1.462846.
They are not, however, "stable" enough to exist in solid state or even to obtain a pure gas, rather complicated arcane trickery is used to work with (very small amount of) them.
Lithium has rather complicated chemistry, easily forming polyhedral structures when bound to proper partner. For example, methyllithium is a tetramer. The simplest rationalization is that its s- and p-orbitals have very close energies and thus low-energy vacant p-orbitals participate in formation of multicentre electron-deficient bonds.
You may be applying the octet rule to a situation where there is no p orbitals involved, the electronic structure of the (ground state) Li atom. Li has the electronic configuration 1s²2s1. So, the covalent bond is between two 2s orbitals, each with 1 electron. Using the Lewis structure, Li2 is Li:Li and that is a full bonding orbital, there's no p atomic orbitals involved in the bonding which might increase valence to 8 (an octet).
Looking at the electron configuration of lithium ($\ce{(1s)^2(2s)^1}$), it's very difficult for the $\ce{1s}$ electrons to be involved in bond formation/sharing.
The reason is because of the extent of attraction of those electrons in the 1s orbital as they are very close to the nucleus (very stable) and rarely available for any bond formation. Again, say if we were to look at the ionisation energy required to extract those electrons in the $\ce{1s}$ orbital, you would agree with me that it's almost impossible.
Looking at the $\ce{2s}$ orbital, you notice it's not as stable since there is more room for electrons to come and occupy in the $\ce{2s}$ (or $\ce{2p}$) orbital to attain maximum stability.
In short, we can't have a $\ce{Li8}$ molecule.
• @alphonse . Thanks for the correction, I was basing my explanation on most stable bonds/ compounds formed by Li. Some Li compounds are rare and very difficult to isolate so I had taken that angle. I apologise for this mistake and I do agree with permeakra's explanation – xavier_fakerat Mar 18 '17 at 8:10 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7435465455055237, "perplexity": 1545.678198189013}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-16/segments/1585370500482.27/warc/CC-MAIN-20200331115844-20200331145844-00405.warc.gz"} |
http://www.ams.org/mathscinet-getitem?mr=2239345 | MathSciNet bibliographic data MR2239345 (2007f:14002) 14A20 (14D20) Olsson, Martin C. $\underline {\rm Hom}$$\underline {\rm Hom}$-stacks and restriction of scalars. Duke Math. J. 134 (2006), no. 1, 139–164. Article
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http://www.science.gov/topicpages/s/single+transient+test.html | #### Sample records for single transient test
1. The single-blow transient testing technique for platefin heat exchangers
Xing Luo; Wilfried Roetzel
2001-01-01
A new model of the single-blow problem is proposed, considering the lateral heat conduction resistance along the fins, the axial heat conduction along the separating plates and the axial thermal dispersion in the fluid. For platefin heat exchangers made up of stainless steel, the effect of the lateral heat conduction resistance along the fins can usually not be neglected. This
2. Single-Event Transient Testing of Low Dropout PNP Series Linear Voltage Regulators
NASA Technical Reports Server (NTRS)
Adell, Philippe; Allen, Gregory
2013-01-01
As demand for high-speed, on-board, digital-processing integrated circuits on spacecraft increases (field-programmable gate arrays and digital signal processors in particular), the need for the next generation point-of-load (POL) regulator becomes a prominent design issue. Shrinking process nodes have resulted in core rails dropping to values close to 1.0 V, drastically reducing margin to standard switching converters or regulators that power digital ICs. The goal of this task is to perform SET characterization of several commercial POL converters, and provide a discussion of the impact of these results to state-of-the-art digital processing IC through laser and heavy ion testing
3. Single Event Transients in Low Voltage Dropout (LVDO) Voltage Regulators
NASA Technical Reports Server (NTRS)
LaBel, K.; Karsh, J.; Pursley, S.; Kleyner, I.; Katz, R.; Poivey, C.; Kim, H.; Seidleck, C.
2006-01-01
This viewgraph presentation reviews the use of Low Voltage Dropout (LVDO) Voltage Regulators in environments where heavy ion induced Single Event Transients are a concern to the designers.Included in the presentation are results of tests of voltage regulators.
4. Columbia University flow instability experimental program: Volume 12. Single annulus transient test program data tables: Part 1
SciTech Connect
Coutts, D.A.
1993-09-01
The single annulus test program was designed to investigate the onset of flow instability in an annular geometry similar to the fuel assemblies used in the Savannah River Site production reactors. Data files were transmitted from Columbia University to Savannah River Site in a DOS compatible format. This report provides a hardcopy version of the electronic media data files.
5. Channel Transient Simulation Test Figure 1 Channel Transient Test Circuit with 9-bit differential PRBS
E-print Network
Palermo, Sam
Channel Transient Simulation Test Figure 1 Channel Transient Test Circuit with 9-bit differential PRBS Figure 2 Input 9-bit differential PRBS measured at Test+ and Test- #12;Channel Transient6.s4p #12;Channel Transient Simulation Test Figure 6 Waveforms at IN+ and IN- using peters_01_0605_B
6. Igniter heater EMI transient test
NASA Technical Reports Server (NTRS)
Cook, M.
1989-01-01
Testing to evaluate Redesigned Solid Rocket Motor igniter heater electromagnetic interference (EMI) effects on the Safe and Arm (S and A) device was completed. It was suspected that EMI generated by the igniter heater and it's associated electromechanical relay could cause a premature firing of the NASA Standard Initiators (NSIs) inside the S and A. The maximum voltage induced into the NSI fire lines was 1/4 of the NASA specified no-fire limit of one volt (SKB 26100066). As a result, the igniter heaters are not expected to have any adverse EMI effects on the NSIs. The results did show, however, that power switching causes occasional high transients within the igniter heater power cable. These transients could affect the sensitive equipment inside the forward skirt. It is therefore recommended that the electromechanical igniter heater relays be replaced with zero crossing solid state relays. If the solid state relays are installed, it is also recommended that they be tested for EMI transient effects.
7. Single-Event Transients in Voltage Regulators
NASA Technical Reports Server (NTRS)
Johnston, Allan H.; Miyahira, Tetsuo F.; Irom, F.; Laird, Jamie S.
2006-01-01
Single-event transients are investigated for two voltage regulator circuits that are widely used in space. A circuit-level model is developed that can be used to determine how transients are affected by different circuit application conditions. Internal protection circuits-which are affected by load as well as internal thermal effects-can also be triggered from heavy ions, causing dropouts or shutdown ranging from milliseconds to seconds. Although conventional output transients can be reduced by adding load capacitance, that approach is ineffective for dropouts from protection circuitry.
8. Columbia University Flow Instability Experimental Program, Volume 13: Single annulus transient test program data tables, Part 2
SciTech Connect
Coutts, D.A.
1993-09-01
This report is one of a series of reports which document the flow instability testing conducted by Columbia University during 1989 through 1992. This testing was completed as part of AX1811457. This report volume provides a hardcopy version of the thirty-four electronic media files: SA0914(A-H).DAT, SAT0609(A-N).DAT, SAT0612(A-O).DAT.
9. Transient Rayleigh scattering from single semiconductor nanowires
SciTech Connect
Montazeri, Mohammad; Jackson, Howard E.; Smith, Leigh M. [Department of Physics, University of Cincinnati, Cincinnati, OH 45221-0011 (United States); Yarrison-Rice, Jan M. [Department of Physics, Miami University, Oxford, OH 45056 (United States); Kang, Jung-Hyun; Gao, Qiang; Tan, Hark Hoe; Jagadish, Chennupati [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)
2013-12-04
Transient Rayleigh scattering spectroscopy is a new pump-probe technique to study the dynamics and cooling of photo-excited carriers in single semiconductor nanowires. By studying the evolution of the transient Rayleigh spectrum in time after excitation, one can measure the time evolution of the density and temperature of photo-excited electron-hole plasma (EHP) as they equilibrate with lattice. This provides detailed information of dynamics and cooling of carriers including linear and bimolecular recombination properties, carrier transport characteristics, and the energy-loss rate of hot electron-hole plasma through the emission of LO and acoustic phonons.
10. Features of postfailure fuel behavior in transient overpower and transient undercooled\\/overpower tests in the transient reactor test facility
R. C. Doerner; T. H. Bauer; J. A. Morman; J. W. Holland
1992-01-01
Prototypic oxide fuel was subjected to simulated, fast reactor severe accident conditions in a series of in-pile tests in the Transient Reactor Test Facility reactor. Seven experiments were performed on fresh and previously irradiated oxide fuel pins under transient overpower and transient undercooled. overpower accident conditions. For each of the tests, fuel motions were observed by the hodoscope. Hodoscope data
11. Single Event Transients in Linear Integrated Circuits
NASA Technical Reports Server (NTRS)
Buchner, Stephen; McMorrow, Dale
2005-01-01
On November 5, 2001, a processor reset occurred on board the Microwave Anisotropy Probe (MAP), a NASA mission to measure the anisotropy of the microwave radiation left over from the Big Bang. The reset caused the spacecraft to enter a safehold mode from which it took several days to recover. Were that to happen regularly, the entire mission would be compromised, so it was important to find the cause of the reset and, if possible, to mitigate it. NASA assembled a team of engineers that included experts in radiation effects to tackle the problem. The first clue was the observation that the processor reset occurred during a solar event characterized by large increases in the proton and heavy ion fluxes emitted by the sun. To the radiation effects engineers on the team, this strongly suggested that particle radiation might be the culprit, particularly when it was discovered that the reset circuit contained three voltage comparators (LM139). Previous testing revealed that large voltage transients, or glitches appeared at the output of the LM139 when it was exposed to a beam of heavy ions [NI96]. The function of the reset circuit was to monitor the supply voltage and to issue a reset command to the processor should the voltage fall below a reference of 2.5 V [PO02]. Eventually, the team of engineers concluded that ionizing particle radiation from the solar event produced a negative voltage transient on the output of one of the LM139s sufficiently large to reset the processor on MAP. Fortunately, as of the end of 2004, only two such resets have occurred. The reset on MAP was not the first malfunction on a spacecraft attributed to a transient. That occurred shortly after the launch of NASA s TOPEX/Poseidon satellite in 1992. It was suspected, and later confirmed, that an anomaly in the Earth Sensor was caused by a transient in an operational amplifier (OP-15) [KO93]. Over the next few years, problems on TDRS, CASSINI, [PR02] SOHO [HA99,HA01] and TERRA were also attributed to transients. In some cases, such events produced resets by falsely triggering circuits designed to protect against over- voltage or over-current. On at least three occasions, transients caused satellites to switch into "safe mode" in which most of the systems on board the satellites were powered down for an extended period. By the time the satellites were reconfigured and returned to full operational state, much scientific data had been lost. Fortunately, no permanent damage occurred in any of the systems and they were all successfully re-activated.
12. International Conference on Power Systems Transients IPST 2003 in Hong Kong Transient Testing of Protection Relays
E-print Network
electromagnetic transients, application testing, auto- mated testing, protective relays, digital simulators IInternational Conference on Power Systems Transients IPST 2003 in Hong Kong 1 Transient Testing meth- odology based on the use of transients. The paper outlines examples of test results that can
13. Results from transient tests and spherical valve closure tests, Raccoon Mountain Pumped-Storage Plant
SciTech Connect
March, P.A.
1984-09-01
Tests were conducted at the Raccoon Mountain Pumped-Storage Plant to obtain data on hydraulic system characteristics during transient-state operation, to compare measured values for system pressures and surge levels with design values, to provide information for review of hydaulic transient computations, and to provide confirmation that the spherical valves are capable of shutting off plant flow under emergency conditions. The tests included single-unit load rejection, single-unit pump power loss, multi-unit emergency shutdown from generating, multi-unit emergency shutdown from pumping, and spherical valve closure.
14. Transient tests on an MHD thruster
SciTech Connect
Pierson, E.S. (Purdue Univ., Hammond, IN (United States). Dept. of Engineering); Libera, J.; Petrick, M. (Argonne National Lab., IL (United States). Energy Systems Div.)
1993-01-01
Three different types of transient tests were made -- coast downs to zero voltage and current under open circuit and short circuit conditions, reverses where the applied voltage was reversed to the same or a different value, and jumps where the voltage applied to the thruster was increased without a change in polarity. Most except the coast downs were dons both quickly (voltage changes as fast as possible) and slowly (6 s to complete the voltage change). A few slower (12 s) transients were done. Transient runs were made for water conductivities of 16.2 and 5.09 S/m. In all cases steady-state conditions were established and several seconds of data taken before initiating the transients. Data were measured every 0.75 to 1 .5 second over the time interval of interest. Particular attention was paid to looking for evidence of gas bubbles, and to the chance of the voltage profiles between the electrodes. The data are interpreted based on the behavior of the power supply and the thruster.
15. Transient well testing in two-phase geothermal reservoirs
SciTech Connect
Aydelotte, S.R.
1980-03-01
A study of well test analysis techniques in two-phase geothermal reservoirs has been conducted using a three-dimensional, two-phase, wellbore and reservoir simulation model. Well tests from Cerro Prieto and the Hawaiian Geothermal project have been history matched. Using these well tests as a base, the influence of reservoir permeability, porosity, thickness, and heat capacity, along with flow rate and fracturing were studied. Single and two-phase transient well test equations were used to analyze these tests with poor results due to rapidly changing fluid properties and inability to calculate the flowing steam saturation in the reservoir. The injection of cold water into the reservoir does give good data from which formation properties can be calculated.
16. Transient test of suspension electronics for gyroscope
NASA Astrophysics Data System (ADS)
Ito, P. H.
1985-07-01
The rotor suspension electronics of an electrostatic gyro suspension system is required to perform flawlessly to sustain the life of the gyro. Transient abnormalities as short as one millisecond duration will cause the spinning rotor to come in contact with the surrounding electrodes and result in destruction of the gyro. Thus, not infrequently after a catastrophic dropped rotor incident no trace of the fault is evident upon ensuing check of the system. To remedy this problem a built in test (BIT) system is used to provide fault isolation. The test circuitry is built into the navigation system electronics and integrated with the system program. The fault isolation electronics comprise sensor circuits to monitor functional subdivisions of the electronic suspension system for signal abnormality and a processing circuit which receives the sensor circuit outputs and identifies the primary source of the fault. The faults are detected and the source is flagged at the time of occurrance. The output of the fault isolation electronics is a latched coded readout which is fed to the navigation computer for memory storage and any appropriate follow-up system action, such as power shutdown. After initialization by the computer, the fault isolation function is an automatic operation by the electronic circuitry.
17. 908 Transient Digitizer Self-Test Modification John Wertenbaker
E-print Network
Princeton Plasma Physics Laboratory
;#12;#12;#12;#12;#12;#12;#12;#12;#12;#12;#12;#12;908 Transient Digitizer Self-Test Modification John Wertenbaker 9/16/2010 It was discovered that some 908 Transient Digitizers were going into self-test mode
18. Transient analysis of the 1991 Hijiori Shallow Reservoir Circulation Test
SciTech Connect
Hyodo, M.; Shinohara, N.; Takasugi, S.; Wright, C.A.; Conant, R..
1996-01-24
Like any dynamic system, HDR reservoirs cannot be fully characterized by their steady-state behavior. Circulation tests analysis should be performed on both the steady-state response and the transient response of HDR systems. Transient analysis allows not only estimation of critical reservoir parameters and how these parameters change with operating conditions / history, but transient analysis also aids in evaluating the feasibility of various modes of HDR system operation (base load, load following, etc.). This paper details the transient analysis of NEDO's FY 1991 Shallow Reservoir Circulation Test at the Hijiori HDR site in Japan. Reservoir fluid storage is carefully bounded through the employment of two distinct methods for calculation of the fluid storage from the observed transient response. A brief discussion is also included of the distribution of reservoir fluid storage; the relationship between pressure, reservoir stress, and apparent reservoir capacitance; and appropriate circulation test design to facilitate transient analysis.
19. Method and device for measuring single-shot transient signals
DOEpatents
Yin, Yan
2004-05-18
Methods, apparatus, and systems, including computer program products, implementing and using techniques for measuring multi-channel single-shot transient signals. A signal acquisition unit receives one or more single-shot pulses from a multi-channel source. An optical-fiber recirculating loop reproduces the one or more received single-shot optical pulses to form a first multi-channel pulse train for circulation in the recirculating loop, and a second multi-channel pulse train for display on a display device. The optical-fiber recirculating loop also optically amplifies the first circulating pulse train to compensate for signal losses and performs optical multi-channel noise filtration.
20. Transient Signal Analysis is a digital device testing method that is based on the analysis of voltage transients at multi-
E-print Network
Plusquellic, James
Abstract Transient Signal Analysis is a digital device testing method that is based on the analysis of voltage transients at multi- ple test points. The power supply transient signals of an 8-bit multiplier-free and defective devices in both simulations and hardware. 1.0 Introduction Transient Signal Analysis (TSA
1. Transient Signal Analysis is a digital device testing method that is based on the analysis of voltage transients at multi-
E-print Network
Plusquellic, James
Abstract Transient Signal Analysis is a digital device testing method that is based on the analysis of voltage transients at multi- ple test points and on IDD switching transients on the sup- ply rails. We show that it is possible to identify defective devices by analyzing the transient signals produced
2. Transient Signal Analysis is a digital device testing method that is based on the analysis of voltage transients at multi-
E-print Network
Plusquellic, James
Abstract Transient Signal Analysis is a digital device testing method that is based on the analysis of voltage transients at multi- ple test points and on IDD switching transients on the sup- ply rails. We show that it is possible to identify defective devices by analyzing the transient signals measured
3. Transient test of suspension electronics for gyroscope
P. H. Ito
1985-01-01
The rotor suspension electronics of an electrostatic gyro suspension system is required to perform flawlessly to sustain the life of the gyro. Transient abnormalities as short as one millisecond duration will cause the spinning rotor to come in contact with the surrounding electrodes and result in destruction of the gyro. Thus, not infrequently after a catastrophic dropped rotor incident no
4. Single event induced transients in I/O devices - A characterization
NASA Technical Reports Server (NTRS)
Newberry, D. M.; Kaye, D. H.; Soli, G. A.
1990-01-01
The results of single-event upset (SEU) testing performed to evaluate the parametric transients, i.e., amplitude and duration, in several I/O devices, and the impact of these transients are discussed. The failure rate of these devices is dependent on the susceptibility of interconnected devices to the resulting transient change in the output of the I/O device. This failure rate, which is a function of the susceptibility of the interconnected device as well as the SEU response of the I/O device itself, may be significantly different from an upset rate calculated without taking these factors into account. The impact at the system level is discussed by way of an example.
5. 40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle
Code of Federal Regulations, 2012 CFR
2012-07-01
...2012-07-01 2012-07-01 false Transient Test Driving Cycle E Appendix...Appendix E to Subpart S of Part 51Transient Test Driving Cycle (I) Driver's trace. All excursions in the transient driving cycle shall be...
6. 40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle
Code of Federal Regulations, 2014 CFR
2014-07-01
...2014-07-01 2014-07-01 false Transient Test Driving Cycle E Appendix...Appendix E to Subpart S of Part 51Transient Test Driving Cycle (I) Driver's trace. All excursions in the transient driving cycle shall be...
7. 40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle
Code of Federal Regulations, 2011 CFR
2011-07-01
...2011-07-01 2011-07-01 false Transient Test Driving Cycle E Appendix...Appendix E to Subpart S of Part 51Transient Test Driving Cycle (I) Driver's trace. All excursions in the transient driving cycle shall be...
8. 40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle
Code of Federal Regulations, 2013 CFR
2013-07-01
...2013-07-01 2013-07-01 false Transient Test Driving Cycle E Appendix...Appendix E to Subpart S of Part 51Transient Test Driving Cycle (I) Driver's trace. All excursions in the transient driving cycle shall be...
9. Transient Signal Analysis is a digital device testing method that is based on the analysis of volt-age transients at multiple test points. In this paper, the power supply transient signals from sim-
E-print Network
Plusquellic, James
Abstract Transient Signal Analysis is a digital device testing method that is based on the analysis of volt- age transients at multiple test points. In this paper, the power supply transient signals from and defective devices. 1.0 Introduction Transient Signal Analysis (TSA) is a parametric approach to testing
10. Behavior of modern metallic fuel in treat transient overpower tests
SciTech Connect
Bauer, T.H.; Wright, A.E.; Robinson, W.R.; Holland, J.W.; Rhodes, E.A. (Argonne National Lab., IL (United States). Reactor Analysis and Safety Div.)
1990-12-01
In this paper results and analyses of margin to cladding failure and prefailure axial expansion of metallic fuel are reported for Transient Reactor Test Facility in-pile transient overpower tests M2 through M7. These include the first such tests on binary and ternary alloy fuel of the Integral Fast Reactor concept and fuel burnups to 10 at. %. The fuel was tested at full coolant flow and subjected to an exponential power rise on an 8-s period until either incipient or actual cladding failure was achieved Objectives, designs, and methods are described with emphasis on developments unique to metal fuel safety testing. Test results include the following: temperature, flow, and pressure data; fuel motion diagnostic data from the fast neutron hodoscope; and test remains described by both destructive and nondestructive posttest examination.
11. Transient response characteristics of test chamber Mach number
NASA Technical Reports Server (NTRS)
Tcheng, P.
1976-01-01
The transient dynamic characteristics of a test chamber Mach number was established for a disturbance initiated in the test chamber. An approximate linear expression was given, showing that the change in the Mach number is linearly proportional to the algebraic sum of the static pressure change in the test chamber and the stagnation pressure change. The static pressure change is the dominating factor. The two pressure changes were also calculated for small Mach number variations, and these results were applied to instrumentation requirements.
12. SINGLE HEATER TEST FINAL REPORT
SciTech Connect
J.B. Cho
1999-05-01
The Single Heater Test is the first of the in-situ thermal tests conducted by the U.S. Department of Energy as part of its program of characterizing Yucca Mountain in Nevada as the potential site for a proposed deep geologic repository for the disposal of spent nuclear fuel and high-level nuclear waste. The Site Characterization Plan (DOE 1988) contained an extensive plan of in-situ thermal tests aimed at understanding specific aspects of the response of the local rock-mass around the potential repository to the heat from the radioactive decay of the emplaced waste. With the refocusing of the Site Characterization Plan by the ''Civilian Radioactive Waste Management Program Plan'' (DOE 1994), a consolidated thermal testing program emerged by 1995 as documented in the reports ''In-Situ Thermal Testing Program Strategy'' (DOE 1995) and ''Updated In-Situ Thermal Testing Program Strategy'' (CRWMS M&O 1997a). The concept of the Single Heater Test took shape in the summer of 1995 and detailed planning and design of the test started with the beginning fiscal year 1996. The overall objective of the Single Heater Test was to gain an understanding of the coupled thermal, mechanical, hydrological, and chemical processes that are anticipated to occur in the local rock-mass in the potential repository as a result of heat from radioactive decay of the emplaced waste. This included making a priori predictions of the test results using existing models and subsequently refining or modifying the models, on the basis of comparative and interpretive analyses of the measurements and predictions. A second, no less important, objective was to try out, in a full-scale field setting, the various instruments and equipment to be employed in the future on a much larger, more complex, thermal test of longer duration, such as the Drift Scale Test. This ''shake down'' or trial aspect of the Single Heater Test applied not just to the hardware, but also to the teamwork and cooperation between multiple organizations performing their part in the test.
13. 40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle
Code of Federal Regulations, 2010 CFR
2010-07-01
...2010-07-01 false Transient Test Driving Cycle E Appendix...SUBMITTAL OF IMPLEMENTATION PLANS Inspection/Maintenance Program...Part 51Transient Test Driving Cycle (I...these limits shall cause a test to be void. In...
14. A Technique for Transient Thermal Testing of Thick Structures
NASA Technical Reports Server (NTRS)
Horn, Thomas J.; Richards, W. Lance; Gong, Leslie
1997-01-01
A new open-loop heat flux control technique has been developed to conduct transient thermal testing of thick, thermally-conductive aerospace structures. This technique uses calibration of the radiant heater system power level as a function of heat flux, predicted aerodynamic heat flux, and the properties of an instrumented test article. An iterative process was used to generate open-loop heater power profiles prior to each transient thermal test. Differences between the measured and predicted surface temperatures were used to refine the heater power level command profiles through the iteration process. This iteration process has reduced the effects of environmental and test system design factors, which are normally compensated for by closed-loop temperature control, to acceptable levels. The final revised heater power profiles resulted in measured temperature time histories which deviated less than 25 F from the predicted surface temperatures.
15. Plasma-Catalysis During Temperature Transient Testing
SciTech Connect
Hoard, John
2001-08-05
A combination of catalysts is used together with nonthermal plasma in simulated diesel exhaust, while the gas temperature is varied. The catalysts both store and convert pollutants. As a result, pollutant concentrations during temperature ramps are different than those at steady state conditions. The data are presented for plasma followed by BaY, alumina, and Pt catalysts in simulated exhaust. When temperature ramps from high to low, apparent NOx conversion is quite high. However, when temperature is ramped from low to high, lower apparent conversions are seen. In a typical test cycle, average NOx conversion between 100 and 400 C is 60%. Peak conversion during the down ramp is over 90%, and minimum conversion during the up ramp is 30%. The composition of the effluent gas also varies during the temperature cycle. Intermediates such as methyl nitrate and hydrogen cyanide are not present following the combination of catalysts.
16. Intelligent transient transitions detection of LRE test bed
NASA Astrophysics Data System (ADS)
Zhu, Fengyu; Shen, Zhengguang; Wang, Qi
2013-01-01
Health Monitoring Systems is an implementation of monitoring strategies for complex systems whereby avoiding catastrophic failure, extending life and leading to improved asset management. A Health Monitoring Systems generally encompasses intelligence at many levels and sub-systems including sensors, actuators, devices, etc. In this paper, a smart sensor is studied, which is use to detect transient transitions of liquid-propellant rocket engines test bed. In consideration of dramatic changes of variable condition, wavelet decomposition is used to work real time in areas. Contrast to traditional Fourier transform method, the major advantage of adding wavelet analysis is the ability to detect transient transitions as well as obtaining the frequency content using a much smaller data set. Historically, transient transitions were only detected by offline analysis of the data. The methods proposed in this paper provide an opportunity to detect transient transitions automatically as well as many additional data anomalies, and provide improved data-correction and sensor health diagnostic abilities. The developed algorithms have been tested on actual rocket test data.
17. Parametric Thermal Models of the Transient Reactor Test Facility (TREAT)
SciTech Connect
2014-03-01
This work supports the restart of transient testing in the United States using the Department of Energys Transient Reactor Test Facility at the Idaho National Laboratory. It also supports the Global Threat Reduction Initiative by reducing proliferation risk of high enriched uranium fuel. The work involves the creation of a nuclear fuel assembly model using the fuel performance code known as BISON. The model simulates the thermal behavior of a nuclear fuel assembly during steady state and transient operational modes. Additional models of the same geometry but differing material properties are created to perform parametric studies. The results show that fuel and cladding thermal conductivity have the greatest effect on fuel temperature under the steady state operational mode. Fuel density and fuel specific heat have the greatest effect for transient operational model. When considering a new fuel type it is recommended to use materials that decrease the specific heat of the fuel and the thermal conductivity of the fuels cladding in order to deal with higher density fuels that accompany the LEU conversion process. Data on the latest operating conditions of TREAT need to be attained in order to validate BISONs results. BISONs models for TREAT (material models, boundary convection models) are modest and need additional work to ensure accuracy and confidence in results.
18. Radiation hardness evaluations of 65 nm fully depleted silicon on insulator and bulk processes by measuring single event transient pulse widths and single event upset rates
NASA Astrophysics Data System (ADS)
Furuta, Jun; Sonezaki, Eiji; Kobayashi, Kazutoshi
2015-04-01
We measure single event transient (SET) pulse widths on inverter chains and single event upset (SEU) rates on flip-flops (FFs) fabricated in 65 nm fully depleted silicon on insulator (FD-SOI) and bulk processes. The layout designs of test chips are strictly identical between their processes besides buried oxide (BOX) layers. Experimental results show that neutron-induced SEU and SET rates in the FD-SOI process are 230 and 450 lower than those in the bulk process, respectively.
19. Analysis of Transient Pressure Tests for Olkaria Exploration Wells
SciTech Connect
Haukwa, Charles B.
1987-01-20
Analysis of transient pressure tests for Olkaria West wells shows that both infinite acting and double porosity models can be used to analyze the well behaviour and infer reservoir properties from fall-off steps of long enough duration, in wells where no significant thermal recovery occurs. The double porosity model gives better estimates of reservoir properties than the infinite acting model, for long fall-off steps in wells intercepting fractures. Semilog methods give fairly good estimates of reservoir transmissivity for the long fall-off steps but are highly inaccurate when used independently, especially for the short fall-off steps conducted in most of the wells. Double porosity models can also be used for recovery test analyses where two phase transients are not significant. 6 refs., 11 figs., 8 tabs.
20. 40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?
Code of Federal Regulations, 2013 CFR
2013-07-01
...2013-07-01 2013-07-01 false What transient duty cycles apply for laboratory testing...Test Procedures 1048.510 What transient duty cycles apply for laboratory testing...Appendix II to determine whether it meets the transient emission standards in ...
1. 40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?
Code of Federal Regulations, 2014 CFR
2014-07-01
...2014-07-01 2014-07-01 false What transient duty cycles apply for laboratory testing...Test Procedures 1048.510 What transient duty cycles apply for laboratory testing...Appendix II to determine whether it meets the transient emission standards in ...
2. 40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?
Code of Federal Regulations, 2011 CFR
2011-07-01
...2011-07-01 2011-07-01 false What transient duty cycles apply for laboratory testing...Test Procedures 1048.510 What transient duty cycles apply for laboratory testing...Appendix II to determine whether it meets the transient emission standards in ...
3. 40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?
Code of Federal Regulations, 2012 CFR
2012-07-01
...2012-07-01 2012-07-01 false What transient duty cycles apply for laboratory testing...Test Procedures 1048.510 What transient duty cycles apply for laboratory testing...Appendix II to determine whether it meets the transient emission standards in ...
4. 40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?
Code of Federal Regulations, 2010 CFR
2010-07-01
...2010-07-01 2010-07-01 false What transient duty cycles apply for laboratory testing...Test Procedures 1048.510 What transient duty cycles apply for laboratory testing...Appendix II to determine whether it meets the transient emission standards in ...
5. Heavy-ion-induced digital single event transients in a 180 nm fully depleted SOI process
E-print Network
Gouker, Pascale M.
Heavy-ion-induced single events transients (SETs) in advanced digital circuits are a significant reliability issue for space-based systems. SET pulse widths in silicon-on-insulator (SOI) technologies are often significantly ...
6. Results of Single-Event Transient Measurements Conducted by the Jet Propulsion Laboratory
Farokh Irom; Tetsuo F. Miyahira
2008-01-01
This paper reports recent single-event transient results for a variety of microelectronic devices that include differential line receivers, drivers and transceiver. The data was collected to evaluate these devices for possible use in NASA spacecraft.
7. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?
Code of Federal Regulations, 2011 CFR
2011-07-01
...false Which duty cycles do I use for transient testing? 1039.510 Section 1039...510 Which duty cycles do I use for transient testing? (a) Measure emissions...dynamometer with one of the following transient duty cycles to determine whether it...
8. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?
Code of Federal Regulations, 2010 CFR
2010-07-01
...false Which duty cycles do I use for transient testing? 1039.510 Section 1039...510 Which duty cycles do I use for transient testing? (a) Measure emissions...dynamometer with one of the following transient duty cycles to determine whether it...
9. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?
Code of Federal Regulations, 2012 CFR
2012-07-01
...false Which duty cycles do I use for transient testing? 1039.510 Section 1039...510 Which duty cycles do I use for transient testing? (a) Measure emissions...dynamometer with one of the following transient duty cycles to determine whether it...
10. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?
Code of Federal Regulations, 2014 CFR
2014-07-01
...false Which duty cycles do I use for transient testing? 1039.510 Section 1039...510 Which duty cycles do I use for transient testing? (a) Measure emissions...dynamometer with one of the following transient duty cycles to determine whether it...
11. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?
Code of Federal Regulations, 2013 CFR
2013-07-01
...false Which duty cycles do I use for transient testing? 1039.510 Section 1039...510 Which duty cycles do I use for transient testing? (a) Measure emissions...dynamometer with one of the following transient duty cycles to determine whether it...
12. Large transient fault current test of an electrical roll ring
NASA Technical Reports Server (NTRS)
Yenni, Edward J.; Birchenough, Arthur G.
1992-01-01
The space station uses precision rotary gimbals to provide for sun tracking of its photoelectric arrays. Electrical power, command signals and data are transferred across the gimbals by roll rings. Roll rings have been shown to be capable of highly efficient electrical transmission and long life, through tests conducted at the NASA Lewis Research Center and Honeywell's Satellite and Space Systems Division in Phoenix, AZ. Large potential fault currents inherent to the power system's DC distribution architecture, have brought about the need to evaluate the effects of large transient fault currents on roll rings. A test recently conducted at Lewis subjected a roll ring to a simulated worst case space station electrical fault. The system model used to obtain the fault profile is described, along with details of the reduced order circuit that was used to simulate the fault. Test results comparing roll ring performance before and after the fault are also presented.
13. Behavior of metallic fuel in treat transient overpower tests
SciTech Connect
Bauer, T.H.; Wright, A.E.; Robinson, W.R.; Klickman, A.E.
1988-01-01
Results and analyses are reported for TREAT in-pile transient overpower tests of margin to cladding failure and pre-failure axial expansion of metallic fuel. In all cases the power rise was exponential on an 8 s period until either incipient or actual cladding failure was achieved. Test fuel included EBR-II driver fuel and ternary alloy, the reference fuel of the Intergral Fast Reactor concept. Test pin burnup spanned the widest range available. The nature of the observed cladding failure and resultant fuel dispersals is described. Simple models are presented which describe observed cladding failures and pre-failure axial expansions yet are general enough to apply to all metal fuel types.
14. Single Event Transients in Voltage Regulators for FPGA Power Supply Applications
NASA Technical Reports Server (NTRS)
Poivey, Christian; Sanders, Anthony; Kim, Hak; Phan, Anthony; Forney, Jim; LaBel, Kenneth A.; Karsh, Jeremy; Pursley, Scott; Kleyner, Igor; Katz, Richard
2006-01-01
As with other bipolar analog devices, voltage regulators are known to be sensitive to single event transients (SET). In typical applications, large output capacitors are used to provide noise immunity. Therefore, since SET amplitude and duration are generally small, they are often of secondary importance due to this capacitance filtering. In low voltage applications, however, even small SET are a concern. Over-voltages may cause destructive conditions. Under-voltages may cause functional interrupts and may also trigger electrical latchup conditions. In addition, internal protection circuits which are affected by load as well as internal thermal effects can also be triggered from heavy ions, causing dropouts or shutdown ranging from milliseconds to seconds. In the case of FPGA power supplies applications, SETS are critical. For example, in the case of Actel FPGA RTAX family, core power supply voltage is 1.5V. Manufacturer specifies an absolute maximum rating of 1.6V and recommended operating conditions between 1.425V and 1.575V. Therefore, according to the manufacturer, any transient of amplitude greater than 75 mV can disrupt normal circuit functions, and overvoltages greater than 100 mV may damage the FPGA. We tested five low dropout voltage regulators for SET sensitivity under a large range of circuit application conditions.
15. Transient Analysis Used to Study Thermal Radiation Effects in Single and Composite Semitransparent Layers
NASA Technical Reports Server (NTRS)
1996-01-01
In a continuing in-house program at the NASA Lewis Research Center, analytical and numerical methods are being developed to apply radiative analysis to predict transient temperature distributions and heat flows in partially transmitting materials. Results have been obtained for a single plane layer, and a transient analysis is being developed for a two-layer composite where each layer has a different refractive index. Because the ceramic refractive indices are larger than one, internal reflections are produced at the surfaces and at the internal interface. Reflections tend to distribute energy within a layer, and this affects the transient temperature distributions.
16. Generation of single-cycle THz transients with high electric-field amplitudes
T. Bartel; P. Gaal; K. Reimann; Michael Woerner; Thomas Elsaesser
2005-01-01
Single-cycle terahertz (THz) transients in the frequency range 0.3-7 THz with electric-field amplitudes of more than 400 kV\\/cm are generated by four-wave mixing of the fundamental and the second harmonic of 25 fs pulses from a Ti:sapphire amplifier in ionized air. These transients are fully characterized by electro-optic sampling with ZnTe and GaP crystals. One can tune the center frequency
17. PFR\\/Treat Safety Experiments: HEDL Transient Test Program Engineering Test Plan
M. A. Hoffman; I. L. Metcalf; D. L. Myron
1981-01-01
The purpose of the PFR\\/TREAT Safety Test Program is to obtain experimental data of fuel pin behavior during hypothetical, unprotected accidents for cores of large liquid metal cooled fast breeder reactors. The steady state and transient experiments, which will be performed under the joint program, are to be as prototypic of fast reactor performance as is possible. The specific objectives
18. Slow transient overpower tests - C04, C05 and L03. [LMFBR
G. E. Culley; R. Herbert; D. L. Myron; M. H. Wood; G. R. Bowen
1984-01-01
Among the low probability LMFBR accident scenarios addressed by the collaborative US\\/UK transient testing program is the slow transient overpower ramp resulting from the hypothetical event of a control rod runaway with failure to trip. This has been simulated in US's TREAT facility with three tests on irradiated driver fuel from the UK's Prototype Fast Reactor. Tests C04 and C05
19. Single-voxel recording of voltage transients in dendritic spines.
PubMed
Acker, Corey D; Yan, Ping; Loew, Leslie M
2011-07-20
We report sensitive recording of membrane potential in single dendritic spines in cortical neurons within a brain slice using two-photon excitation and a new, fluorinated, intracellularly loaded organic dye, di-2-AN(F)EPPTEA. With a two-photon excitation wavelength of 1060 nm, we achieve voltage sensitivity of >16% change in fluorescence per 100 mV. By targeting single spines in single-voxel recordings, we attain excellent single/noise quality, with back-propagating action potentials (bAPs) visible in single sweeps while recording at 10 kHz. This recording rate allows us to reliably assess fast bAP dynamics on single sweeps including bAP rise times of 0.5 ms. The amplitude and propagation delays of the bAPs are similar among different spines located within the same dendritic region, and this is true despite large differences in spine size. The interregion differences in bAP waveforms in spines vary in relation to their distance from the soma and the caliber of their parent dendrites. PMID:21767473
20. Irisin in Blood Increases Transiently after Single Sessions of Intense Endurance Exercise and Heavy Strength Training
PubMed Central
Nygaard, Hvard; Slettalkken, Gunnar; Vegge, Geir; Hollan, Ivana; Whist, Jon Elling; Strand, Tor; Rnnestad, Bent R.; Ellefsen, Stian
2015-01-01
Purpose Irisin is a recently identified exercise-induced hormone that increases energy expenditure, at least in rodents. The main purpose of this study was to test the hypothesis that Irisin increases acutely in blood after singular sessions of intense endurance exercise (END) and heavy strength training (STR). Secondary, we wanted to explore the relationship between body composition and exercise-induced effects on irisin, and the effect of END and STR on muscular expression of the irisin gene FNDC5. Methods Nine moderately trained healthy subjects performed three test days using a randomized and standardized crossover design: one day with 60 minutes of END, one day with 60 minutes of STR, and one day without exercise (CON). Venous blood was sampled over a period of 24h on the exercise days. Results Both END and STR led to transient increases in irisin concentrations in blood, peaking immediately after END and one hour after STR, before gradually returning to baseline. Irisin responses to STR, but not END, showed a consistently strong negative correlation with proportions of lean body mass. Neither END nor STR affected expression of FNDC5, measured 4h after training sessions, though both protocols led to pronounced increases in PGC-1? expression, which is involved in transcriptional control of FNDC5. Conclusion The results strongly suggest that single sessions of intense endurance exercise and heavy strength training lead to transient increases in irisin concentrations in blood. This was not accompanied by increased FNDC5 expression, measured 4h post-exercise. The results suggest that irisin responses to resistance exercise are higher in individuals with lower proportions of lean body mass. PMID:25781950
1. Single cell pattern formation and transient cytoskeletal arrays
PubMed Central
Bement, William M.; von Dassow, George
2015-01-01
A major goal of developmental biology is to explain the emergence of pattern in cell layers, tissues and organs. Developmental biologists now accept that reaction diffusion-based mechanisms are broadly employed in developing organisms to direct pattern formation. Here we briefly consider these mechanisms and then apply some of the concepts derived from them to several processes that occur in single cells: wound repair, yeast budding, and cytokinesis. Two conclusions emerge from this analysis: first, there is considerable overlap at the level of general mechanisms between developmental and single cell pattern formation; second, dynamic structures based on the actin cytoskeleton may be far more ordered than is generally recognized. PMID:24529246
2. 40 CFR Appendix I to Part 1037 - Heavy-Duty Transient Chassis Test Cycle
Code of Federal Regulations, 2012 CFR
2012-07-01
...342012-07-01 2012-07-01false Heavy-Duty Transient Chassis Test CycleI Appendix I to Part 1037Protection...1037, App. I Appendix I to Part 1037Heavy-Duty Transient Chassis Test CycleTimesec. SpeedmphSpeedm/s...
3. 40 CFR Appendix I to Part 1037 - Heavy-Duty Transient Chassis Test Cycle
Code of Federal Regulations, 2014 CFR
2014-07-01
...332014-07-01 2014-07-01false Heavy-Duty Transient Chassis Test CycleI Appendix I to Part 1037Protection...1037, App. I Appendix I to Part 1037Heavy-Duty Transient Chassis Test CycleTimesec. SpeedmphSpeedm/s...
4. 40 CFR Appendix I to Part 1037 - Heavy-Duty Transient Chassis Test Cycle
Code of Federal Regulations, 2013 CFR
2013-07-01
...342013-07-01 2013-07-01false Heavy-Duty Transient Chassis Test CycleI Appendix I to Part 1037Protection...1037, App. I Appendix I to Part 1037Heavy-Duty Transient Chassis Test CycleTimesec. SpeedmphSpeedm/s...
5. Single Sample t-Test
NSDL National Science Digital Library
Lowry, Richard, 1940-
This page will perform a t-test for the significance of the difference between the observed mean of a sample and a hypothetical mean of the population from which the sample is randomly drawn. The user will be asked to specify the sample size as the page opens.
6. Laboratory tests for single-event effects
S. Buchner; D. McMorrow; J. Melinger; A. B. Camdbell
1996-01-01
Integrated circuits are currently tested at accelerators for their susceptibility to single-event effects (SEE's). However, because of the cost and limited accessibility associated with accelerator testing, there is considerable interest in developing alternate testing methods. Two laboratory techniques for measuring SEE, one involving a pulsed laser and the other 252Cf, are described in detail in this paper. The pulsed laser
7. Revisiting single photon avalanche diode current-voltage modeling and transient characteristics
SciTech Connect
Javitt, M.; Savuskan, V., E-mail: [email protected]; Merhav, T. [Department of Electrical Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Nemirovsky, Y. [Department of Electrical Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Kinneret College on the Sea of Galilee (Israel)
2014-05-28
A model for the current-voltage and transient behavior of Single Photon Avalanche Diodes (SPADs) based on device physics is presented. The results of the model are compared to actual measurements and a reasonable fit is seen. Additionally, the model provides a useful tool for designing quenching circuitry and determining optimal operation conditions of the SPAD.
8. Digital Computer Solution of Electromagnetic Transients in Single-and Multiphase Networks
Hermann Dommel
1969-01-01
Electromagnetic transients in arbitrary single- or multiphase networks are solved by a nodal admittance matrix method. The formulation is based on the method of characteristics for distributed parameters and the trapezoidal rule of integration for lumped parameters. Optimally ordered triangular factorization with sparsity techniques is used in the solution. Examples and programming details illustrate the practicality of the method.
9. Arsenazo III and antipyrylazo III calcium transients in single skeletal muscle fibers
PubMed Central
1982-01-01
The metallochrome calcium indicators arsenazo III and antipyrylazo III have been introduced individually into cut single frog skeletal muscle fibers from which calcium transients have been elicited either by action potential stimulation or by voltage-clamp pulses of up to 50 ms in duration. Calcium transients recorded with both dyes at selected wavelengths have similar characteristics when elicited by action potentials. Longer voltage-clamp pulse stimulation reveals differences in the late phases of the optical signals obtained with the two dyes. The effects of different tension blocking methods on Ca transients were compared experimentally. Internal application of EGTA at concentrations up to 3 mM was demonstrated to be efficient in blocking movement artifacts without affecting Ca transients. Higher EGTA concentrations affect the Ca signals' characteristics. Differential effects of internally applied EGTA on tension development as opposed to calcium transients suggest that diffusion with binding from Ca++ release sites to filament overlap sites may be significant. The spectral characteristics of the absorbance transients recorded with arsenazo III suggest that in situ recorded signals cannot be easily interpreted in terms of Ca concentration changes. A more exhaustic knowledge of the dye chemistry and/or in situ complications in the use of the dye will be necessary. PMID:6802933
10. Successful Transient Expression of Cas9 and Single Guide RNA Genes in Chlamydomonas reinhardtii
PubMed Central
Jiang, Wenzhi; Brueggeman, Andrew J.; Horken, Kempton M.; Plucinak, Thomas M.
2014-01-01
The clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 system has become a powerful and precise tool for targeted gene modification (e.g., gene knockout and gene replacement) in numerous eukaryotic organisms. Initial attempts to apply this technology to a model, the single-cell alga, Chlamydomonas reinhardtii, failed to yield cells containing edited genes. To determine if the Cas9 and single guide RNA (sgRNA) genes were functional in C. reinhardtii, we tested the ability of a codon-optimized Cas9 gene along with one of four different sgRNAs to cause targeted gene disruption during a 24-h period immediately following transformation. All three exogenously supplied gene targets as well as the endogenous FKB12 (rapamycin sensitivity) gene of C. reinhardtii displayed distinct Cas9/sgRNA-mediated target site modifications as determined by DNA sequencing of cloned PCR amplicons of the target site region. Success in transient expression of Cas9 and sgRNA genes contrasted with the recovery of only a single rapamycin-resistant colony bearing an appropriately modified FKB12 target site in 16 independent transformation experiments involving >109 cells. Failure to recover transformants with intact or expressed Cas9 genes following transformation with the Cas9 gene alone (or even with a gene encoding a Cas9 lacking nuclease activity) provided strong suggestive evidence for Cas9 toxicity when Cas9 is produced constitutively in C. reinhardtii. The present results provide compelling evidence that Cas9 and sgRNA genes function properly in C. reinhardtii to cause targeted gene modifications and point to the need for a focus on development of methods to properly stem Cas9 production and/or activity following gene editing. PMID:25239977
11. ASST Interconnect Region single phase pressure tests
1992-01-01
The Accelerator System String Test (ASST) single phase line was pressure tested to meet ASME B31.3-1990 piping code requirements. Two test specimens, one without a bellows assembly and one with a bellows assembly, were tested under hydrostatic pressure in 0.689 MPa (100psi) increments. All parts met code requirements except the bellows squirm protector, which met ASST-rated pressure levels but not
12. Single event transient analysis of an SOI operational amplifier for use in low-temperature Martian exploration
NASA Astrophysics Data System (ADS)
Laird, Jamie Stuart; Scheick, Leif; Vizkelethy, Gyorgy; Mojarradi, Mohammad M.; Miyahira, Tetsuo; Chen, Yuan; Blalock, Benjamin; Greenwell, Robert; Terry, Stephen; Doyle, Barney
2007-07-01
The next generation of Martian rovers to be launched by Jet Propulsion Laboratory (JPL) are to examine polar regions where temperatures are extremely low and the absence of an earth-like atmosphere results in high levels of cosmic radiation at ground level. Cosmic rays lead to a plethora of radiation effects including Single Event Transients which can severely degrade microelectronic functionality. As such, a radiation-hardened, temperature compensated CMOS Single-on-insulator (SOI) Operational Amplifier has been designed for JPL by the University of Tennessee and fabricated by Honeywell using the SOI V process. SOI technology has been shown to be far less sensitive to transient effects than both bulk and epilayer Si. Broad beam heavy-ion tests at the University of Texas A&M using Kr and Xe beams of energy 25 MeV/amu were performed to ascertain the duration and severity of the SET for the op-amp configured for a low and high gain application. However, some ambiguity regarding the location of transient formation required the use of a focused MeV ion microbeam. A 36 MeV O 6+ microbeam at the Sandia National Laboratory (SNL) was used to image and verify regions of particular concern.
13. Single pellet crush strength testing of catalysts
SciTech Connect
Brienza, P.K. (Engelhard Corp., Seneca, SC (USA))
1988-09-01
ASTM D-32 Committee on Catalysts has developed a standard test method for single pellet crush strength for formed catalyst shapes. This standard was issued under the fixed designation D 4179. The method is applicable to regular catalyst shapes such as tablets and spheres. Extrudates, granular materials, and other irregular shapes are excluded. The committee continues to work on the development of a method for the single pellet crush testing of extrudates.
14. Creation of a transient vapor nanogap between two fluidic reservoirs for single molecule manipulation
NASA Astrophysics Data System (ADS)
Polonsky, Stanislav; Balagurusamy, Venkat S. K.; Ott, John A.
2014-08-01
We introduce a new experimental technique for manipulating a segment of a charged macromolecule inside a transient nanogap between two fluidic reservoirs. This technique uses an FPGA-driven nanopositioner to control the coupling of a nanopipette with the liquid surface of a fluidic cell. We present results on creating a transient nanogap, triggered by a translocation of double-stranded DNA between a nanopipette and a fluidic cell, and measure the probability to find the molecule near the tip of the nanopipette after closing the gap. The developed platform will enable testing of our recent theoretical predictions for the behavior of charged macromolecule in a nanogap between two fluidic reservoirs.
15. Creation of a transient vapor nanogap between two fluidic reservoirs for single molecule manipulation.
PubMed
Polonsky, Stanislav; Balagurusamy, Venkat S K; Ott, John A
2014-08-01
We introduce a new experimental technique for manipulating a segment of a charged macromolecule inside a transient nanogap between two fluidic reservoirs. This technique uses an FPGA-driven nanopositioner to control the coupling of a nanopipette with the liquid surface of a fluidic cell. We present results on creating a transient nanogap, triggered by a translocation of double-stranded DNA between a nanopipette and a fluidic cell, and measure the probability to find the molecule near the tip of the nanopipette after closing the gap. The developed platform will enable testing of our recent theoretical predictions for the behavior of charged macromolecule in a nanogap between two fluidic reservoirs. PMID:25173286
16. Mixed-Mode Simulation and Analysis of Digital Single Event Transients in Fast CMOSICs
M. Turowski; A. Raman; G. Jablonski
2007-01-01
Single event transient (SET) pulses produced from heavy ion irradiation in digital integrated circuits (ICs) are modeled and analyzed using a mixed-mode approach, that is, three-dimensional (3-D) semiconductor device simulation coupled with a circuit solver. In this paper, we analyze the factors affecting the generation and propagation of digital SET pulses in fast CMOS ICs. Our mixed-mode simulations of various
17. ASST Interconnect Region single phase pressure tests
SciTech Connect
Mendoza, R.
1992-08-01
The Accelerator System String Test (ASST) single phase line was pressure tested to meet ASME B31.3-1990 piping code requirements. Two test specimens, one without a bellows assembly and one with a bellows assembly, were tested under hydrostatic pressure in 0.689 MPa (100psi) increments. All parts met code requirements except the bellows squirm protector, which met ASST-rated pressure levels but not Collider-rated levels, due to inadequate tab weld quality. Extra support such as hose clamps and possible minor redesign would allow the squirm protector to meet ASME code requirements for the Collider.
18. X-33 Injector Ignition Single Cell Test
NASA Technical Reports Server (NTRS)
1997-01-01
The X-33 injector ignition single cell was tested at the Marshall Space Flight Center test stand 116. The X-33 was a sub-scale technology demonstrator prototype of a Reusable Launch Vehicle (RLV) manufactured and named by Lockheed Martin as the Venture Star. The goal of the program was to demonstrate the technologies needed for a full size, single-stage-to-orbit RLV, thus enabling private industry to build and operate the RLV in the first decade of the 21st century. The X-33 program was cancelled in 2001.
19. Transient spectrum of a single-Cooper-pair box with binomial states
E-print Network
Mahmoud Abdel-Aty; Hamada F. Abdel-Hameed; N. Metwally
2006-01-01
We present an analytical expression for the response of a transient spectrum to a single-Cooper-pair box biased by a classical voltage and irradiated by a single-mode quantized field. The exact solution of the model is obtained, by means of which we analyze the analytic form of the fluorescence spectrum using the transitions among the dressed states of the system. An interesting relation between the fluorescence spectrum and the dynamical evolution is found when the initial field states are prepared in binomial states.
20. Effects of Ionizing Radiation on Digital Single Event Transients in a 180-nm Fully Depleted SOI Process
E-print Network
Keast, Craig L.
Effects of ionizing radiation on single event transients are reported for Fully Depleted SOI (FDSOI) technology using experiments and simulations. Logic circuits, i.e. CMOS inverter chains, were irradiated with cobalt-60 ...
1. Computer simulation and experimental study of transient processes in a single-phase voltage transformer
NASA Astrophysics Data System (ADS)
Kruzhaev, A. V.; Elagin, I. A.; Pavleino, M. A.; Dmitriev, V. A.; Chaly, A. M.
2015-02-01
We perform simulation and experimental investigation of transient processes emerging in a single-phase transformer when it is connected to the network. The transformer model constructed taking into account the saturation of the steel of the core differs from standard models in detailed accounting for the magnetic flux leakage, which is required, for example, for a correct description of inrush current. Universality of the model for the type of transformers under study is ensured by the allowance for eddy current losses and calculation of the magnetic hysteresis in the steel core. The latter makes it possible to estimate the effect of residual magnetization of the core on the form of a transient process, which is studied in detail. The methods for computing model parameters are described and its experimental verification is carried out.
2. Methods Studies on System Identification from Transient Rotor Tests
NASA Technical Reports Server (NTRS)
Hohenemser, K. H.; Banerjee, D.; Yin, S. K.
1975-01-01
Some of the more important methods are discussed that have been used or proposed for aircraft parameter identification. The methods are classified into two groups: Equation error or regression estimates and Bayesian estimates and their derivatives that are based on probabilistic concepts. In both of these two groups the cost function can be optimized either globally over the entire time span of the transient, or sequentially, leading to the formulation of optimum filters. Identifiability problems and the validation of the estimates are briefly outlined, and applications to lifting rotors are discussed.
3. Analysisi Benchmark of the Single Heater Test
SciTech Connect
H.M. Wade; H. Marr; M.J. Anderson
2006-07-27
The Single Heater Test (SHT) is the first of three in-situ thermal tests included in the site characterization program for the potential nuclear waste monitored geologic repository at Yucca Mountain. The heating phase of the SHT started in August 1996 and was concluded in May 1997 after 9 months of heating. Cooling continued until January 1998, at which time post-test characterization of the test block commenced. Numerous thermal, hydrological, mechanical, and chemical sensors monitored the coupled processes in the unsaturated fractured rock mass around the heater (CRWMS M&O 1999). The objective of this calculation is to benchmark a numerical simulation of the rock mass thermal behavior against the extensive data set that is available from the thermal test. The scope is limited to three-dimensional (3-D) numerical simulations of the computational domain of the Single Heater Test and surrounding rock mass. This calculation supports the waste package thermal design methodology, and is developed by Waste Package Department (WPD) under Office of Civilian Radioactive Waste Management (OCRWM) procedure AP-3.12Q, Revision 0, ICN 3, BSCN 1, Calculations.
4. NEXT Single String Integration Test Results
NASA Technical Reports Server (NTRS)
Soulas, George C.; Patterson, Michael J.; Pinero, Luis; Herman, Daniel A.; Snyder, Steven John
2010-01-01
As a critical part of NASA's Evolutionary Xenon Thruster (NEXT) test validation process, a single string integration test was performed on the NEXT ion propulsion system. The objectives of this test were to verify that an integrated system of major NEXT ion propulsion system elements meets project requirements, to demonstrate that the integrated system is functional across the entire power processor and xenon propellant management system input ranges, and to demonstrate to potential users that the NEXT propulsion system is ready for transition to flight. Propulsion system elements included in this system integration test were an engineering model ion thruster, an engineering model propellant management system, an engineering model power processor unit, and a digital control interface unit simulator that acted as a test console. Project requirements that were verified during this system integration test included individual element requirements ; integrated system requirements, and fault handling. This paper will present the results of these tests, which include: integrated ion propulsion system demonstrations of performance, functionality and fault handling; a thruster re-performance acceptance test to establish baseline performance: a risk-reduction PMS-thruster integration test: and propellant management system calibration checks.
5. Mechanism of single-event transient pulse quenching between dummy gate isolated logic nodes
NASA Astrophysics Data System (ADS)
Chen, Jian-Jun; Chi, Ya-Qing; Liang, Bin
2015-01-01
As integrated circuits scale down in size, a single high-energy ion strike often affects multiple adjacent logic nodes. The so-called single-event transient (SET) pulse quenching induced by single-event charge sharing collection has been widely studied. In this paper, SET pulse quenching enhancement is found in dummy gate isolated adjacent logic nodes compared with that isolated by the common shallow trench isolation (STI). The physical mechanism is studied in depth and this isolation technique is explored for SET mitigation in combinational standard cells. Three-dimensional (3D) technology computer-aided design simulation (TCAD) results show that this technique can achieve efficient SET mitigation. Project supported by the National Natural Science Foundation of China (Grant No.61376109) and the Opening Project of National Key Laboratory of Science and Technology on Reliability Physics and Application Technology of Electrical Component, China (Grant No.ZHD201202).
6. Built-in Current Sensor for High Speed Transient Current Testing in Analog CMOS Circuits
S. Yellampalli; N. S. Korivi; J. Marulanda
2008-01-01
In this paper, we present a new built-in current sensor (BICS) for high speed, low voltage degradation transient current (IDDT) testing. This sensor has been designed using forward bias technique to limit the supply voltage degradation caused during transient current peaks to 2% of the supply voltage. A CMOS operational amplifier designed for operation at plusmn2.5 V in 0.5 mum
7. Transient eigenmodes analysis of single-impact cantilever dynamics combining Fourier and wavelet transforms.
PubMed
Pukhova, Valentina; Banfi, Francesco; Ferrini, Gabriele
2015-05-01
The transient eigenmode structure of an interacting cantilever during a single impact on different surfaces evidences the excitation of higher flexural modes and low frequency oscillations. The frequency shift of the fundamental mode after the tip comes into contact with the sample surface allows calculating the tip-sample interaction stiffness and evidences the role of capillary condensation and surface wettability on the cantilever dynamics. Wavelet transforms are used to trace the origin of spectral features in the cantilever spectra and calculate force gradients of the tip-sample interaction. PMID:25837684
8. A chassis test procedure to mimic the heavy-duty engine transient emissions certification test.
PubMed
Clark, N N; McKain, D L
2001-03-01
In-use emissions from vehicles using heavy-duty diesel engines can be significantly higher than the levels obtained during engine certification. These higher levels may be caused by a combination of degradation of engine components, poor engine maintenance, degradation or failure of emissions after-treatment devices, and engine and emissions system tampering. A direct comparison of in-use vehicle emissions with engine certification levels, however, is not possible without removing an engine from the vehicle in order to perform engine dynamometer emissions testing. The goal of this research was to develop a chassis test procedure that mimics the engine performance, and as such the expected emissions levels, from the engine certification emissions test prescribed in the U.S. Code of Federal Regulations. Emissions measurements were taken from two engines during testing on an engine dynamometer using the transient heavy-duty Federal Test Procedure (FTP). Additionally, each engine was installed in an appropriate vehicle, and emissions measurements were taken using a chassis dynamometer while employing a vehicle driving schedule intended to match closely the instantaneous torque and speed schedule of the engine FTP. Engine and chassis testing was performed with the engines in stock (unmodified) condition as well as in several modes to simulate either tampered or poorly maintained conditions. The use of a chassis test as a predictive tool for determining whether an engine in a vehicle would pass the engine certification test has proven to be worthwhile. Analysis of the data shows that identification of chassis-mounted engines with NOx emissions above certification levels is possible by employing engine-specific correction factors. In the case of PM emissions, significant data scatter allowed only the identification of gross PM emitters. Engine tampering and poor maintenance can raise PM and NOx emissions, and these increases can be correctly identified by a chassis test. Analysis of chassis and engine CO and HC emissions did not reveal a strong enough correlation to warrant the use of the chassis test for emissions screening of these two pollutants. PMID:11266106
9. Combined single channel and single molecule detection identifies subunit composition of STIM1-activated transient receptor potential canonical (TRPC) channels.
PubMed
Asanov, Alexander; Sampieri, Alicia; Moreno, Claudia; Pacheco, Jonathan; Salgado, Alfonso; Sherry, Ryan; Vaca, Luis
2015-01-01
Depletion of intracellular calcium ion stores initiates a rapid cascade of events culminating with the activation of the so-called Store-Operated Channels (SOC) at the plasma membrane. Calcium influx via SOC is essential in the initiation of calcium-dependent intracellular signaling and for the refilling of internal calcium stores, ensuring the regeneration of the signaling cascade. In spite of the significance of this evolutionary conserved mechanism, the molecular identity of SOC has been the center of a heated controversy spanning over the last 20 years. Initial studies positioned some members of the transient receptor potential canonical (TRPC) channel superfamily of channels (with the more robust evidence pointing to TRPC1) as a putative SOC. Recent evidence indicates that Stromal Interacting Molecule 1 (STIM1) activates some members from the TRPC family of channels. However, the exact subunit composition of TRPC channels remains undetermined to this date. To identify the subunit composition of STIM1-activated TRPC channels, we developed novel method, which combines single channel electrophysiological measurements based on the patch clamp technique with single molecule fluorescence imaging. We termed this method Single ion Channel Single Molecule Detection technique (SC-SMD). Using SC-SMD method, we have obtained direct evidence of the subunit composition of TRPC channels activated by STIM1. Furthermore, our electrophysiological-imaging SC-SMD method provides evidence at the molecular level of the mechanism by which STIM1 and calmodulin antagonize to modulate TRPC channel activity. PMID:25465892
10. Comparison of Above Bandgap Laser and MeV Ion Induced Single Event Transients in High-Speed Si Photonic Devices
NASA Technical Reports Server (NTRS)
Laird, Jamie S.; Hirao, Toshio; Onoda, Shinobu; Itoh, Hisayoshi; Edmonds, Larry; Johnston, Allan
2006-01-01
We illustrate inherent differences between Single Event Transients generated by an above bandgap picosecond lasers and MeV heavy ions by comparing transient currents collected with an ion microbeam and picosecond laser with varying track waist.
11. An Investigation of the Ability to Recover from Transients Following Failures for Single-Pilot Rotorcraft
NASA Technical Reports Server (NTRS)
Mansur, M. Hossein; Schroeder, Jeffery A.
1988-01-01
A moving-base simulation was conducted to investigate a pilot's ability to recover from transients following single-axis hard-over failures of the flight-control system. The investigation was performed in conjunction with a host simulation that examined the influence of control modes on a single pilot's ability to perform various mission elements under high-workload conditions. The NASA Ames large-amplitude-motion Vertical Motion Simulator (VMS) was utilized, and the experimental variables were the failure axis, the severity of the failure, and the airspeed at which the failure occurred. Other factors, such as pilot workload and terrain and obstacle proximity at the time of failure, were kept as constant as possible within the framework of the host simulation task scenarios. No explicit failure warnings were presented to the pilot. Data from the experiment are shown, and pilot ratings are compared with the proposed handling-qualities requirements for military rotorcraft. Results indicate that the current proposed failure transient requirements may need revision.
12. Probing Transient Copper Chaperone-Wilson Disease Protein Interactions at the Single-Molecule Level with Nanovesicle Trapping
E-print Network
Chen, Peng
Probing Transient Copper Chaperone-Wilson Disease Protein Interactions at the Single-Molecule Level cells, the copper chaperone Hah1 and the Wilson disease protein (WDP) constitute a copper transport pathwaysHah1 is a single-domain cytoplasmic protein; WDP is a multidomain pro- tein anchored on organelle
13. Pressure transient testing and productivity analysis for horizontal wells
E-print Network
Cheng, Yueming
2004-11-15
This work studied the productivity evaluation and well test analysis of horizontal wells. The major components of this work consist of a 3D coupled reservoir/wellbore model, a productivity evaluation, a deconvolution ...
14. Measurement of Relative Permeability Using Single-Step Transient Flow Centrifuge Experiments
NASA Astrophysics Data System (ADS)
van den Berg, E. H.; Perfect, E.; Mayes, M. A.
2007-12-01
Steady-state flow centrifuge methods have been widely used to determine the relative permeability function, krw, of porous media. The centripetal acceleration greatly accelerates the speed at which equilibrium conditions are found in drainage or imbibition experiments. While equilibrium conditions are required by steady- state flow centrifuge methods, transient flow centrifuge methods utilize the time variant adaptation of state variables (e.g. fluid saturation, pressure or flux) to sudden changes in boundary conditions. Transient flow centrifuge experiments were conducted using a commercial rock core ultracentrifuge to displace wetting fluids from an initially fully-saturated sample by non-wetting fluids. The cumulative production of wetting fluid leaving the sample was recorded using an automated digital camera recording system. The time series of cumulative wetting fluid production forms the input for the objective function of inverse numerical modeling efforts and for the independent estimation of krw using an analytical solution for the transient flow of fluids through a porous medium in a centripetal field (the Hagoort method). In this study, single-step transient outflow experiments were run on Berea sandstone cores. The angular velocity was 942 sec-1. Independent laboratory techniques were used to measure the saturated water content, ?s, and the intrinsic permeability, ksat. Besides these measurements, synthetic production data were generated with forward simulations of Hydrus-1D using the standard van Genuchten parameters for 'Sand' and 'Silt' soils. The models simulated acceleration of the centrifuge rotor during the first ~95 seconds of the experiment by increasing the angular velocity stepwise in 2.5 second intervals to 733 sec-1. The data were interpreted using a modified version of the Hagoort method in which numerical derivatives are used to compute the slope of the production curve in order to calculate relative saturation and the corresponding krw function. We also used Hydrus-1D to inversely estimate the parameters of the van Genuchten relative permeability model, ?r, a, n, and l. Systematic variation of the initial parameters values used in the inverse simulations showed that some of the parameter estimates obtained with inverse simulation were non-unique. For both the synthetic simulations and the measurement data, the difference between the original krw curve and the krw curve obtained with inverse simulations was most sensitive to the initial estimate of the shape parameter, n. Estimation of initial parameter values could be augmented by the good correspondence between the krw curves obtained with the Hagoort method and those used and obtained in numerical (inverse) simulations. Transient flow centrifuge experiments and their interpretation are expected to have applications in predicting infiltration and remediation of environmental contamination within the vadose zone.
15. Analysis of Single-Event Transients in Integer Frequency Dividers and Hardness Assurance Implications for Phase-Locked Loops
Thomas Daniel Loveless; Brian D. Olson; Bharat L. Bhuva; W. Timothy Holman; Craig C. Hafer; Lloyd W. Massengill
2009-01-01
Single-event transients (SET) are analyzed in integer-N frequency dividers configured internal and external to a closed-loop phase-locked loop (PLL) circuit. Simulations, corroborated by experimental results, indicate that the location and gain of the frequency divider in any PLL arrangement strongly influence both the error rate of the PLL circuit and the propagation of transients through the closed-loop. The probability of
16. 49 CFR 232.305 - Single car air brake tests.
Code of Federal Regulations, 2010 CFR
2010-10-01
...2010-10-01 2010-10-01 false Single car air brake tests. 232.305 Section 232.305...and Testing Requirements 232.305 Single car air brake tests. (a) Single car air brake tests shall be performed by a...
17. 49 CFR 232.305 - Single car air brake tests.
Code of Federal Regulations, 2013 CFR
2013-10-01
...2013-10-01 2013-10-01 false Single car air brake tests. 232.305 Section 232.305...and Testing Requirements 232.305 Single car air brake tests. (a) Single car air brake tests shall be performed by a...
18. 49 CFR 232.305 - Single car air brake tests.
Code of Federal Regulations, 2011 CFR
2011-10-01
...2011-10-01 2011-10-01 false Single car air brake tests. 232.305 Section 232.305...and Testing Requirements 232.305 Single car air brake tests. (a) Single car air brake tests shall be performed by a...
19. 49 CFR 232.305 - Single car air brake tests.
Code of Federal Regulations, 2014 CFR
2014-10-01
...2014-10-01 2014-10-01 false Single car air brake tests. 232.305 Section 232.305...and Testing Requirements 232.305 Single car air brake tests. (a) Single car air brake tests shall be performed by a...
20. 49 CFR 232.305 - Single car air brake tests.
Code of Federal Regulations, 2012 CFR
2012-10-01
...2012-10-01 2012-10-01 false Single car air brake tests. 232.305 Section 232.305...and Testing Requirements 232.305 Single car air brake tests. (a) Single car air brake tests shall be performed by a...
1. Transient Signal Analysis (TSA) is a Go/No-Go device test-ing method that is based on the analysis of voltage tran-
E-print Network
Plusquellic, James
Abstract Transient Signal Analysis (TSA) is a Go/No-Go device test- ing method that is based the relationship between the power supply transient signal data and the actual delays. Once established, prediction delays from an additional set of critical path simula- tions. 1.0 Introduction Transient Signal Analysis
2. Testing and Lubrication for Single Race Bearings
SciTech Connect
Steinhoff, R.G.
1998-03-04
Three ES and H-compatible lubricants (Environment, Safety and Health) for single race bearing applications and one hybrid-material single race bearings were evaluated and compared against single race bearings with trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon), which is an ozone-depleting solvent. Vydax has been used as a bearing lubricant in stronglink mechanisms since 1974. Hybrid bearings with silicon nitride balls and molded glass-nylon-Teflon retainers, bearings lubricated with titanium carbide (TiC) on the balls, bearings lubricated with sputtered MoS{sub 2} on races and retainers, and bearings lubricated with electrophoretically deposited MoS{sub 2} were evaluated. The bearings were maintained in a preloaded state in bearing cartridges during cycling and vibration tests. Bearings with electrophoretically deposited MoS{sub 2} performed as well as bearings lubricated with Vydax and were the best performing candidate. All candidates were suitable for low preload applications. Bearings with TiC coated balls and bearings lubricated with sputtered MoS{sub 2} on the races and retainers performed well at high preloads, though not as well as bearings lubricated with electrophoretic deposition of MoS{sub 2}. Bearings with silicon nitride balls were not suitable for high preload applications.
3. On-line testing of transient and crosstalk faults affecting interconnections of FPGA-implemented systems
Cecilia Metra; Andrea Pagano; Bruno Ricc
2001-01-01
In this paper we propose a self-checking scheme for the on-line testing of transient and crosstalk faults affecting the interconnections of synchronous systems implemented using Field-Programmable Gate-Arrays (FPGAs). An FPGA prototype has been implemented, whose correct operation has been verified by means of post-layout simulations and experimental measurements
4. Single Event Effects (SEE) Testing of Embedded DSP Cores within Microsemi RTAX4000D Field Programmable Gate Array (FPGA) Devices
NASA Technical Reports Server (NTRS)
Perez, Christopher E.; Berg, Melanie D.; Friendlich, Mark R.
2011-01-01
Motivation for this work is: (1) Accurately characterize digital signal processor (DSP) core single-event effect (SEE) behavior (2) Test DSP cores across a large frequency range and across various input conditions (3) Isolate SEE analysis to DSP cores alone (4) Interpret SEE analysis in terms of single-event upsets (SEUs) and single-event transients (SETs) (5) Provide flight missions with accurate estimate of DSP core error rates and error signatures.
5. Experimental Investigation of Launch Vehicle Transient Input Simulation in Payload Tests
NASA Technical Reports Server (NTRS)
Rader, P.; Berry, R.
1979-01-01
The technique of electronically simulating the structural dynamics of a launch vehicle in transient tests of payloads using multiple vibration excitation systems was investigated. The development of computer programs to determine transfer functions, synthesize shaker forcing functions, and control vibration exciters is described. A demonstration test using the techniques was described and results are presented. The evaluation of the potential for applying this technique to large Shuttle payloads is discussed.
6. 49 CFR 238.311 - Single car test.
Code of Federal Regulations, 2012 CFR
2012-10-01
...2012-10-01 2012-10-01 false Single car test. 238.311 Section 238.311 Transportation...Passenger Equipment 238.311 Single car test. (a) Except for self-propelled passenger cars, single car tests of all passenger...
7. 49 CFR 238.311 - Single car test.
Code of Federal Regulations, 2013 CFR
2013-10-01
...2013-10-01 2013-10-01 false Single car test. 238.311 Section 238.311 Transportation...Passenger Equipment 238.311 Single car test. (a) Except for self-propelled passenger cars, single car tests of all passenger...
8. 49 CFR 238.311 - Single car test.
Code of Federal Regulations, 2014 CFR
2014-10-01
...2014-10-01 2014-10-01 false Single car test. 238.311 Section 238.311 Transportation...Passenger Equipment 238.311 Single car test. (a) Except for self-propelled passenger cars, single car tests of all passenger...
9. 49 CFR 238.311 - Single car test.
Code of Federal Regulations, 2010 CFR
2010-10-01
...2010-10-01 2010-10-01 false Single car test. 238.311 Section 238.311 Transportation...Passenger Equipment 238.311 Single car test. (a) Except for self-propelled passenger cars, single car tests of all passenger...
10. 49 CFR 238.311 - Single car test.
Code of Federal Regulations, 2011 CFR
2011-10-01
...2011-10-01 2011-10-01 false Single car test. 238.311 Section 238.311 Transportation...Passenger Equipment 238.311 Single car test. (a) Except for self-propelled passenger cars, single car tests of all passenger...
11. Transient getter scheme for the Tokamak Fusion Test Reactor
SciTech Connect
Cecchi, J.L.; Cohen, S.A.; Sredniawski, J.J.
1980-01-01
The ability of the Tokamak Fusion Test Reactor (TFTR) to attain the largest fusion power gain depends critically on minimizing plasma contamination and controlling the densities of the reacting deuterium and tritium. Experiments on a number of tokamaks have demonstrated that gettering over an appreciable surface area (greater than or equal to 10%) of the vacuum vessel greatly facilitates both of these objectives. One particular problem in implementing a surface pumping system in TFTR, however, is a restriction on the maximum allowable tritium content of the getter. This restriction could require regeneration of the absorbed tritium after as few as 50 machine pulses. We have developed a scheme utilizing SAES Zr/Al getter modules which obviates the need for such frequent interruptions of machine operation by taking advantage of the pulsed operation of TFTR. With the Zr/Al getter at temperatures between 500/sup 0/C to 600/sup 0/C it is possible to achieve a quasi-steady state in the tritium loading where the quantity of tritium desorbed between pulses is equal to the quantity which is absorbed during a pulse. Since frequent thermal cycling is not required, this scheme also reduces the possibility of Zr/Al getter material fatigue.
12. Transient oxidative stress and inflammation after intraperitoneal administration of multiwalled carbon nanotubes functionalized with single strand DNA in rats
SciTech Connect
Clichici, Simona, E-mail: [email protected] [Department of Physiology, University of Medicine and Pharmacy, Cluj-Napoca (Romania)] [Department of Physiology, University of Medicine and Pharmacy, Cluj-Napoca (Romania); Biris, Alexandru Radu [National R and D Institute of Isotopic and Molecular Technologies, Cluj-Napoca (Romania)] [National R and D Institute of Isotopic and Molecular Technologies, Cluj-Napoca (Romania); Tabaran, Flaviu [University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca (Romania)] [University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca (Romania); Filip, Adriana [Department of Physiology, University of Medicine and Pharmacy, Cluj-Napoca (Romania)] [Department of Physiology, University of Medicine and Pharmacy, Cluj-Napoca (Romania)
2012-03-15
Multi-walled carbon nanotubes (MWCNTs) are widely used for nanotechnology. Their impact on living organisms is, however, not entirely clarified. Oxidative stress and inflammation seem to be the key mechanisms involved in MWCNTs' cytotoxicity. Until present, pulmonary and skin models were the main tested experimental designs to assess carbon nanotubes' toxicity. The systemic administration of MWCNTs is essential, with respect for future medical applications. Our research is performed on Wistar rats and is focused on the dynamics of oxidative stress parameters in blood and liver and pro-inflammatory cytokines in liver, after single dose (270 mg l{sup ?1}) ip administration of MWCNTs (exterior diameter 1525 nm, interior diameter 1015 nm, surface 88 m{sup 2} g{sup ?1}) functionalized with single strand DNA (ss-DNA). The presence of MWCNTs in blood was assessed by Raman spectroscopy, while in liver histological examination and confocal microscopy were used. It was found that ss-DNA-MWCNTs induce oxidative stress in plasma and liver, with the return of the tested parameters to normal values, 6 h after ip injection of nanotubes, with the exception of reduced glutathione in plasma. The inflammatory cytokines (TNF-?, IL-1?) had a similar pattern of evolution. We also assessed the level of ERK1/2 and the phosphorylation of p65 subunit of NF-kB in liver that had a transient increase and returned to normal at the end of the tested period. Our results demonstrate that ss-DNA-MWCNTs produce oxidative stress and inflammation, but with a transient pattern. Given the fact that antioxidants modify the profile not only for oxidative stress, but also of inflammation, the dynamics of these alterations may be of practical importance for future protective strategies. -- Highlights: ? ss-DNA-MWCNTs ip administration induce oxidative stress in plasma and liver. ? ss-DNA-MWCNTs ip administration determine liver inflammation. ? ERK1/2 and p65 phosphorylated NF-KB increase in liver after MWCNTs ip injection. ? All the alterations, except plasma GSH, return to normal within 6 days.
13. Transient Signal Analysis (TSA) is a parametric device testing technique based on the analysis of dynamic (transient) current
E-print Network
Plusquellic, James
the accuracy of predicting multiple path delays under these conditions. Abbreviations: iDDT: A time varying (ac on the analysis of dynamic (transient) current (iDDT) drawn by the core logic from the power supply pads in a CMOS variations caused by defects and to obtain delay information in defect free chips. Phase spectra of transient
14. APOBEC3A deaminates transiently exposed single-strand DNA during LINE-1 retrotransposition
PubMed Central
Richardson, Sandra R; Narvaiza, Iigo; Planegger, Randy A; Weitzman, Matthew D; Moran, John V
2014-01-01
Long INterspersed Element-1 (LINE-1 or L1) retrotransposition poses a mutagenic threat to human genomes. Human cells have therefore evolved strategies to regulate L1 retrotransposition. The APOBEC3 (A3) gene family consists of seven enzymes that catalyze deamination of cytidine nucleotides to uridine nucleotides (C-to-U) in single-strand DNA substrates. Among these enzymes, APOBEC3A (A3A) is the most potent inhibitor of L1 retrotransposition in cultured cell assays. However, previous characterization of L1 retrotransposition events generated in the presence of A3A did not yield evidence of deamination. Thus, the molecular mechanism by which A3A inhibits L1 retrotransposition has remained enigmatic. Here, we have used in vitro and in vivo assays to demonstrate that A3A can inhibit L1 retrotransposition by deaminating transiently exposed single-strand DNA that arises during the process of L1 integration. These data provide a mechanistic explanation of how the A3A cytidine deaminase protein can inhibit L1 retrotransposition. DOI: http://dx.doi.org/10.7554/eLife.02008.001 PMID:24843014
15. Fast Detection of the Metallic State of Individual Single-Walled Carbon Nanotubes Using a Transient-Absorption Optical Microscope
E-print Network
Zhong, Zhaohui
imaging method holds the potential of serving as a high-speed metallicity-mapping tool to assistFast Detection of the Metallic State of Individual Single-Walled Carbon Nanotubes Using a Transient method for fast, contact-free mapping of metallicity in individual SWNTs. We employ the phase
16. Addition to the Supporting Information to Probing Transient Copper Chaperone-Wilson Disease Protein Interactions at the Single-
E-print Network
Chen, Peng
S-1 Addition to the Supporting Information to Probing Transient Copper Chaperone-Wilson Disease Protein Interactions at the Single- Molecule Level with Nanovesicle Trapping Jaime J. Bentez,a Aaron M-pair protein association in a nanovesicle as in our experiments, both k1 and k2 in above equations need
17. Fabrication and Test of Ferromagnetic Single-Electron-Transistors
E-print Network
Haviland, David
Fabrication and Test of Ferromagnetic Single-Electron-Transistors Diploma Thesis Katrin Pappert of Nanostructure Physics Diplomarbeit Fabrication and Test of Ferromagnetic Single-Electron-Transistors von Katrin in optimizing the process for the fabrication of ferromagnetic single electron transistors (FM
18. Quantifying Transient 3D Dynamical Phenomena of Single mRNA Particles in Live Yeast Cell Measurements
PubMed Central
Calderon, Christopher P.; Thompson, Michael A.; Casolari, Jason M.; Paffenroth, Randy C.; Moerner, W. E.
2013-01-01
Single-particle tracking (SPT) has been extensively used to obtain information about diffusion and directed motion in a wide range of biological applications. Recently, new methods have appeared for obtaining precise (10s of nm) spatial information in three dimensions (3D) with high temporal resolution (measurements obtained every 4ms), which promise to more accurately sense the true dynamical behavior in the natural 3D cellular environment. Despite the quantitative 3D tracking information, the range of mathematical methods for extracting information about the underlying system has been limited mostly to mean-squared displacement analysis and other techniques not accounting for complex 3D kinetic interactions. There is a great need for new analysis tools aiming to more fully extract the biological information content from in vivo SPT measurements. High-resolution SPT experimental data has enormous potential to objectively scrutinize various proposed mechanistic schemes arising from theoretical biophysics and cell biology. At the same time, methods for rigorously checking the statistical consistency of both model assumptions and estimated parameters against observed experimental data (i.e. goodness-of-fit tests) have not received great attention. We demonstrate methods enabling (1) estimation of the parameters of 3D stochastic differential equation (SDE) models of the underlying dynamics given only one trajectory; and (2) construction of hypothesis tests checking the consistency of the fitted model with the observed trajectory so that extracted parameters are not over-interpreted (the tools are applicable to linear or nonlinear SDEs calibrated from non-stationary time series data). The approach is demonstrated on high-resolution 3D trajectories of single ARG3 mRNA particles in yeast cells in order to show the power of the methods in detecting signatures of transient directed transport. The methods presented are generally relevant to a wide variety of 2D and 3D SPT tracking applications. PMID:24015725
19. RAPID Boron-dilution Transient Tests for OECD/CSNI International Standard Problem No. 43
SciTech Connect
Gavrilas, Mirela [University of Maryland, College Park, MD 20742 (United States); Palazov, Vesselin [ISL Inc., Rockville MD. (United States); Woods, Brian [Dominion Generation, Richmond VA. (United States)
2002-07-01
The University of Maryland 2 x 4 Thermalhydraulic Loop Facility (UM 2 x 4 Loop) collected code verification data for rapid boron-dilution (RBD) transients. This paper addresses the objectives of recently completed RBD tests and the redesign of the UM 2 x 4 Loop facility for the four test series of the current program. The UM 2 x 4 Loop facility is described in sufficient detail to permit the preparation of input models for code verification. Initial and boundary conditions are given. The OECD/CSNI International Standard Problem No. 43 (ISP 43) figures of merit for comparison of code predictions to experimental findings are described. Specific values for the most representative figures of merit are given for the two closed test series: injection of a front and injection of a slug without downcomer bypass. Because flow regime is a substantial factor in downcomer mixing for RBD transients, the effect of inertial forces on figures of merit is discussed. Tests with downcomer flowrates that fall below the transition to turbulence are shown to exhibit behaviors different from tests ran at downcomer Reynolds numbers that fall in the turbulent regime. Specifically, it is shown that in high flowrate tests mixing is more vigorous when evaluated from a global perspective, but regions of the slug can remain more segregated from the ambient primary coolant than in slow tests. (authors)
20. Testing fluvial erosion models using the transient response of bedrock rivers to tectonic forcing in the Apennines, Italy
E-print Network
Cowie, Patience
Testing fluvial erosion models using the transient response of bedrock rivers to tectonic forcing fluvial erosion models. However, some recent studies of bedrock erosion conclude that transient river long profiles can be approximately characterized by a transportlimited erosion model, while other authors
1. Transient Effects In The Acrylamide Quenching Of Single Tryptophan Proteins, Observed Using Frequency-Domain Fluorometry
NASA Astrophysics Data System (ADS)
Lakowicz, Joseph R.; Johnson, Michael L.; Gryczynski, Ignacy; Szmacinski, Henryk; Joshi, N.; Laczko, G.
1988-06-01
We used GHz frequency-domain fluorometry to examine the tryptophan intensity decays of NATA (M-acetyl-L-tryptophanamide), gly-trp-gly, and the single tryptophan proteins ACTH, E. nuclease and ribonuclease T, (Rhase 1%). In all cases the intensity decays became more heterogeneous in the presence of quenching, which we attribute to a time-dependent rate constant for quenching (transient effects). The frequency-domain data were analyzed using the Smoluchowski model (exp(-t/t 2b/T)) and the radiation boundary condition (RBC) model. In contrast to the IT model, the RBC model does not assume the fluorophore-quencher pair is immediately deactivated, but rather assumes a rate constant for deactivation of the pair (K) as well as a mutual diffusion coefficient (D). The RBC model provides dramatically improved fits to the data. The values of both D and decreases progressively in the order listed above, which is with decreasing exposure to the aqueous phase. Because the RBC model may not be strictly correct in homogeneous solution, and probably less so in the hindered anisotropic environment of the proteins, the recovered values of D and IC should be regarded as apparent values. The recovered intensity decays can be compared with molecular dynamic calculations of quencher trajectories in proteins.
2. Transient Rayleigh scattering: a new probe of picosecond carrier dynamics in a single semiconductor nanowire.
PubMed
Montazeri, Mohammad; Jackson, Howard E; Smith, Leigh M; Yarrison-Rice, Jan M; Kang, Jung-Hyun; Gao, Qiang; Tan, Hark Hoe; Jagadish, Chennupati
2012-10-10
Using a new technique, transient Rayleigh scattering, we show that measurements from a single GaAs/AlGaAs core-shell semiconductor nanowire provide sensitive and detailed information on the time evolution of the density and temperature of the electrons and holes after photoexcitation by an intense laser pulse. Through band filling, band gap renormalization, and plasma screening, the presence of a dense and hot electron-hole plasma directly influences the real and imaginary parts of the complex index of refraction that in turn affects the spectral dependence of the Rayleigh scattering cross-section in well-defined ways. By measuring this spectral dependence as a function of time, we directly determine the thermodynamically independent density and temperature of the electrons and holes as a function of time after pulsed excitation as the carriers thermalize to the lattice temperature. We successfully model the results by including ambipolar transport, recombination, and cooling through optic and acoustic phonon emission that quantify the hole mobility at ?68,000 cm(2)/Vs, linear decay constant at 380 ps, bimolecular recombination rate at 4.8 10(-9) cm(3)/s and the energy-loss rate of plasma due to optical and acoustic phonon emission. PMID:22974064
3. Muscle calcium transient. Effect of post-stimulus length changes in single fibers
PubMed Central
1984-01-01
We examined the effects of post-stimulus length changes on voltage- clamped, aequorin-injected single muscle fibers from the barnacle Balanus nubilus. Extra light (extra calcium) is seen when the fiber is allowed to shorten (a small percentage) during the declining phase of the calcium transient. The opposite is observed when the fiber is stretched. Increasing the extent of shortening increases the amount of extra calcium, as does decreasing the temperature. The extra calcium probably comes from the myofilaments and not from the sarcoplasmic reticulum because (a) there is a strong correlation between the extra calcium and the level of activation; (b) there is a strong correlation between the extra calcium and the amount of force redeveloped after a length change; and (c) the time course of the appearance of the extra calcium is intermediate between that of the free calcium concentration and that of force. We suggest (a) that the calcium binding to the activating myofibrillar proteins is sensitive to muscle length or muscle force, and (b) that there is a pool of bound calcium (activating calcium) that waxes and wanes with a time course intermediate between the free calcium concentration and force. PMID:6319546
4. Nonlinear transient wave excitation as a new tool in model testing
SciTech Connect
Clauss, G.F.; Kuehnlein, W.L. [Berlin Univ. of Technology (Germany). Inst. of Naval Architecture and Ocean Engineering
1996-12-31
Short extension transient waves with tailor-made spectra are extremely efficient for model testing. For small water elevations a linear description of the wave field is satisfactory. With higher transient wave trains, however, the linear description becomes increasingly inaccurate, and a new numerical technique must be developed. Such a new method is based on the fact that short and high wave groups with strong nonlinear characteristics evolve from long and low wave groups, which are characterized by linear principles. As the total energy of the transient wave is invariant during its metamorphosis, the initial linear Fourier spectrum is selected as the backbone of wave information or as the primordial cell from which all nonlinearities are hatched. Based on the initial Fourier spectrum which is the core of the wave information operator the shape variation of the linear transient wave train during propagation is calculated. At selected positions the nonlinear expansion is accomplished by solving the mutually dependent particle motion equations in time domain. The proposed new method uses a numerical nonlinear description of transient wave trains as a function of time or space for any fixed or moving reference point. At its primordial state it is based on a linear superposition of wave information which is complemented by an expanded velocity potential to calculate nonlinear surface elevations, particle motions, velocities, and accelerations. After the nonlinear wave trains converge and pass the concentration point only to diverge and fade away as long, low and linear wave groups, the primordial linear Fourier spectrum can be found again at the end of the development. This step can be used to monitor the transformation. Wave energy spectra and the shape of the wave train can be designed with special regard to the proposed task. Based on these data the entire wave field can be determined.
5. Evaluation of naturally fractured gas shale production utilizing multiwell transient tests: A field study
SciTech Connect
Chen, C.C.; Alam, J.; Blanton, T.L.; Vozniak, J.P.
1984-05-01
A series of multiple well transient tests were conducted in a Devonian shale gas field in Meigs County, Ohio. Production parameters were quantified and it was determined that the reservoir is highly anisotropic, which is a significant factor in calculating half-fracture length from pressure transient data. Three stimulation treatments, including conventional explosive shooting, nitrogen foam frac, and high energy gas frac (HEGF), were compared on the basis of overall effectiveness and performance. Based on the evaluation of results, the nitrogen foam frac provided the most improved productivity. The study provided new type curves and analytical solutions for the mathematical representation of naturally fractured reservoirs and confirmed that the shale reservoir in Meigs County can be modeled as a dual porosity system using pseudosteady-state gas transfer from the matrix to the fracture system.
6. Testing the single-state dominance hypothesis
SciTech Connect
lvarez-Rodrguez, R. [Universidad Politcnica de Madrid, Avda. Juan Herrera 4, E-28040 Madrid (Spain); Moreno, O.; Moya de Guerra, E. [Universidad Complutense de Madrid, Avda. Complutense, E-28040 Madrid (Spain); Sarriguren, P. [Instituto de Estructura de la Materia (CSIC), Serrano 123, E-28006 Madrid (Spain); imkovic, F. [Comenius University, SK-842 15 Bratislava (Slovakia); Faessler, A. [University of Tbingen, D-72076 Tbingen (Germany)
2013-12-30
We present a theoretical analysis of the single-state dominance hypothesis for the two-neutrino double-beta decay process. The theoretical framework is a proton-neutron QRPA based on a deformed Hartree-Fock mean field with BCS pairing correlations. We focus on the decays of {sup 100}Mo, {sup 116}Cd and {sup 128}Te. We do not find clear evidences for single-state dominance within the present approach.
7. An infrastructure for accurate characterization of single-event transients in digital circuits.
PubMed
Savulimedu Veeravalli, Varadan; Polzer, Thomas; Schmid, Ulrich; Steininger, Andreas; Hofbauer, Michael; Schweiger, Kurt; Dietrich, Horst; Schneider-Hornstein, Kerstin; Zimmermann, Horst; Voss, Kay-Obbe; Merk, Bruno; Hajek, Michael
2013-11-01
We present the architecture and a detailed pre-fabrication analysis of a digital measurement ASIC facilitating long-term irradiation experiments of basic asynchronous circuits, which also demonstrates the suitability of the general approach for obtaining accurate radiation failure models developed in our FATAL project. Our ASIC design combines radiation targets like Muller C-elements and elastic pipelines as well as standard combinational gates and flip-flops with an elaborate on-chip measurement infrastructure. Major architectural challenges result from the fact that the latter must operate reliably under the same radiation conditions the target circuits are exposed to, without wasting precious die area for a rad-hard design. A measurement architecture based on multiple non-rad-hard counters is used, which we show to be resilient against double faults, as well as many triple and even higher-multiplicity faults. The design evaluation is done by means of comprehensive fault injection experiments, which are based on detailed Spice models of the target circuits in conjunction with a standard double-exponential current injection model for single-event transients (SET). To be as accurate as possible, the parameters of this current model have been aligned with results obtained from 3D device simulation models, which have in turn been validated and calibrated using micro-beam radiation experiments at the GSI in Darmstadt, Germany. For the latter, target circuits instrumented with high-speed sense amplifiers have been used for analog SET recording. Together with a probabilistic analysis of the sustainable particle flow rates, based on a detailed area analysis and experimental cross-section data, we can conclude that the proposed architecture will indeed sustain significant target hit rates, without exceeding the resilience bound of the measurement infrastructure. PMID:24748694
8. Spray characteristics of single- and three-hole nozzle injectors in ambient air and in a motored single-cylinder test engine
J. P. Hahn; F. J. Hamady; R. M. Schaefer
1994-01-01
The high-speed\\/high-resolution imaging system was used to evaluate two mid-pressure (15 MPa) fuel injector nozzles in ambient air and in a motored single-cylinder test engine. The nozzles are designed for use in the EPA\\/NVFEL program to develop clean and efficient engines that use alternative fuels. The report is part of an ongoing investigation to analyze the transient spray characteristics for
9. Spray characteristics of single- and three-hole nozzle injectors in ambient air and in a motored single-cylinder test engine. Technical report
J. P. Hahn; F. J. Hamady; R. M. Schaefer
1994-01-01
The high-speed\\/high-resolution imaging system was used to evaluate two mid-pressure (15 MPa) fuel injector nozzles in ambient air and in a motored single-cylinder test engine. The nozzles are designed for use in the EPA\\/NVFEL program to develop clean and efficient engines that use alternative fuels. The report is part of an ongoing investigation to analyze the transient spray characteristics for
10. Real-time transient testing and performance of transformer differential relays
SciTech Connect
Stringer, N.T.; Lawhead, L.; Wilkerson, T.; Biggs, J. [Basler Electric Co., Highland, IL (United States); Rockefeller, G.D. [Rockefeller Associates, Inc., Morris Plains, NJ (United States)
1995-12-31
Differential relays are used extensively to provide protection for power transformers. Several issues must be considered in their application to ensure adequate protection. These include transformer magnetizing inrush current, relay burden and current transformer performance. The use of low ratio current transformers in high magnitude fault applications can produce distorted secondary waveforms to the relay whose performance may be directly affected. There is also a relationship between the magnetizing inrush and current transformer performance which may affect the operation of the differential relay. This paper discusses these specific applications and the testing of a transformer differential relay under conditions of saturated CTs using the Electro-Magnetic Transient Program (EMTP).
11. A Generalized Linear Model for Single Event Transient Propagation in Phase-Locked Loops
Thomas Daniel Loveless; Lloyd W. Massengill; W. Timothy Holman; Bharat L. Bhuva; Dale McMorrow; Jeffrey H. Warner
2010-01-01
A first-order linear model is formulated in closed-form for the examination of transient propagation through charge pump phase-locked loops (PLL). As a result, a novel PLL design parameter-the PLL critical time constant-is discovered as the primary factor influencing extraneous transient generation and propagation through the PLL independent of technology node. Various simulations and experiments have been performed on PLL circuits
12. TRAC-PF1 analysis of LOFT steam-generator feedwater transient test L9-1. [PWR
SciTech Connect
Meier, J.K.
1983-01-01
The Transient Reactor Analysis Code (TRAC-PF1) calculations were compared to test data from Loss-of-Fluid Test (LOFT) L9-1, which was a loss-of-feedwater transient. This paper includes descriptions of the test and the TRAC input and compares the TRAC-calculated results with the test data. We conclude that the code predicted the experiment well, given the uncertainties in the boundary conditions. The analysis indicates the need to model all the flow paths and heat structures, and to improve the TRAC wall condensation heat-transfer model.
13. Single shaft automotive gas turbine engine characterization test
NASA Technical Reports Server (NTRS)
Johnson, R. A.
1979-01-01
An automotive gas turbine incorporating a single stage centrifugal compressor and a single stage radial inflow turbine is described. Among the engine's features is the use of wide range variable geometry at the inlet guide vanes, the compressor diffuser vanes, and the turbine inlet vanes to achieve improved part load fuel economy. The engine was tested to determine its performance in both the variable geometry and equivalent fixed geometry modes. Testing was conducted without the originally designed recuperator. Test results were compared with the predicted performance of the nonrecuperative engine based on existing component rig test maps. Agreement between test results and the computer model was achieved.
14. Single Event Effects Testing of the Linfinity SG1525A Pulse Width Modulator Controller
NASA Technical Reports Server (NTRS)
Howard, J. W., Jr.; Carts, M. A.; LaBel, K. A.; Forney, J. D.; Irwin, T. L.
2003-01-01
Pulse Width Modulator (PWM) Controllers are the heart of switching power supply systems in development today. The PWMs considered here have the same integration advantages as many other controllers but it also includes the interface drivers for the follow-on power Field Effect Transistors (FET). Previous work on these types of devices looked into the required test methodologies [ 11 and the impact of radiation on the soft start and shutdown circuits of typically incorporated in the technology [2]. Taking advantage of this previous work this study was undertaken to determine the single event destructive and transient susceptibility of the Linfinity SG1525A Pulse Width Modulator Controller. The device was monitored for transient interruptions in the output signals and for destructive events induced by exposing it to a heavy ion beam at the Texas A&M University Cyclotron Single Event Effects Test Facility. After exposing these devices to the beam, a new upset mode has been identified that can lead to catastrophic power supply system failure if this event would occur while drive power FETs off the two device outputs. The devices and the test methods used will be described first. This will be followed by a brief description of the data collected to date (not all data can be presented with the length constraints of the summary) and a summary of the key results.
15. Hanford single shell tank saltcake cesium removal test plan
SciTech Connect
Duncan, J.B., Westinghouse Hanford
1996-12-11
This document provides the test preparation and conduct of a cesium removal test using Hanford Single Shell Tank Saltcake from tanks 241-BY-110, 241-U-108, 241 U 109, 241-A-101, and 241-S-102 in a benchscale column. The cesium sorbent to be tested is crystalline silicotitanate
16. Transient overvoltages and overcurrents during line fault tests on the Hokkaido-Honshu HVDC line
SciTech Connect
Sasaki, S.; Handa, S.; Ooi, H.
1982-08-01
A series of line fault tests have been conducted at completion of Stage I of the Hokkaido-Honshu HVDC Link of Electric Power Development Co., Ltd., prior to its commercial operation, in order to study transient overvoltages and overcurrents and to confirm safety operation of system protecting devices in case of DC transmission line faults. The Hokkaido-Honshu HVDC Link is a metallic return HVDC overhead line and cable transmission system, currently being a monopolar system. For this, measurements were conducted this time on reverse polarity overvoltages occurring on main line cable, return line overvoltages, fault arc dynamic characteristics, and DC bypass current through the AC system. The results obtained were then compared with the analysis results by the HVDC surge similator or digital simulation conducted for system design prior to the field tests. As a result, a close accordance was found between them, in confirmation of the effectiveness of the analysis method.
17. Testing Single-Parameter Classical Standpoint Cosmology
E-print Network
G. F. Chew
1995-05-30
Experimental tests of homogeneous-universe classical standpoint cosmology are proposed after presentation of conceptual considerations that encourage this radical departure from the standard model. Among predictions of the new model are standpoint age equal to Hubble time, energy-density parameter $\\Omega_0 = 2 - \\sqrt{2} =.586$, and relations between redshift, Hubble-scale distribution of matter and galaxy luminosity and angular diameter. These latter relations coincide with those of the standard model for zero deceleration. With eye to further tests, geodesics of the non-Riemannian standpoint metric are explicitly given. Although a detailed thermodynamic youthful-standpoint'' approximation remains to be developed (for particle mean free path small on standpoint scale), standpoint temperature depending only on standpoint age is a natural concept, paralleling energy density and redshift that perpetuates thermal spectrum for cosmic background radiation. Prospects for primordial nucleosynthesis are promising.
18. Particle Tracking-Based Strategies For Simulating Transport in a Transient Groundwater Flow Field at Yucca Flat, Nevada Test Site, USA
NASA Astrophysics Data System (ADS)
Keating, E. H.; Srinivasan, G.; Kang, Q.; Li, C.; Dash, Z.; Kwicklis, E. M.
2009-12-01
Developing probabilistic-based calculations of contaminant concentrations over the next 1000 years at Yucca Flat, Nevada Test site, require tremendous computational effort in this highly complex hydrogeologic surface environment. The sources of contamination, underground nuclear tests conducted between 1951 and 1992, not only released radionuclides to the subsurface but also created abrupt, significant changes in rock properties and caused large transients in the measured hydraulic gradients. To efficiently model contaminant migration from these sources we use a particle-based approach within a transient flow field. Here, we present results using two methods; first, an explicit representation of time-varying sources using large numbers of particles introduced at source-specific rates over time, each representing a unique mass of solute. This method provides good results, but is computationally expensive since sensitivity to uncertainty in source term and transport parameters can only be explored with discrete process-model runs. The second method employs a convolution method (PLUMECALC) which can efficiently consider a large number of variations in the source terms and in certain transport parameters with a single process-model run. Implementation of this second approach required extension of the existing methodology to conditions of transient flow. We find very good comparison between the two methods on small test problems and excellent computational advantages when applying the convolution method in the NTS application
19. Reliability of the stroop test with single-stimulus presentation.
PubMed
Siegrist, M
1995-12-01
Different versions of the Stroop test are used; however, for most versions of the Stroop test, there are no estimations of reliability. In the present study, stimuli were presented singly on a computer screen. 55 Swiss German subjects were tested. Test-retest reliabilities of 'XXXX' strings and conflicting color words were evaluated. Response latencies and Stroop interference were quite reliable. Single-stimulus presentation made it possible also to estimate internal consistency, which was high for classical Stroop interference in this format. PMID:8684929
20. Performance of a bulb turbine suitable for low prototype head: model test and transient numerical simulation
NASA Astrophysics Data System (ADS)
Zhu, L.; Zhang, H. P.; Zhang, J. G.; Meng, X. C.; Lu, L.
2012-11-01
In this paper, a bulb turbine, with unit specific speed of nq=223.1 min-1 suitable for low prototype head was studied from aspect of its performance. Hydraulic model of the turbine was developed firstly, and then model turbine was designed and manufactured. Performance tests were carried out on high-accuracy hydraulic machinery model universal test rig located at IWHR, including energy, cavitation and pressure fluctuation tests, etc. In order to investigate internal flow field, three-dimensional transient turbulence numerical simulation was conducted on the tested turbine, adopting Reynolds-averaged Navier-Stocks control equations and RNG k-? turbulence model. Test and simulation results show that: (1) hydraulic efficiency of model turbine ?M is up to 91.7%, at the optimum operating point of n11o=165.54 r/min versus Q11o=1.93 m3/s; (2) numerical results agree well with experimental resultsby comparing pressure fluctuation, which shows that pressure amplitude is very low at the optimum operating point; (3) hydraulic loss in Outflow domain accounts for more than 50% total hydraulic loss due to flow separation and secondary flow.
1. Single shot transient suppressor (SSTS) for high current high slew rate microprocessor
Luca Amoroso; Mauro Donati; Xunwei Zhou; Fred C. Lee
1999-01-01
Future generation microprocessors are predicted to exhibit heavier loads and faster transients. Conventional voltage regulator modules (VRM) need a large amount of output filter capacitors to meet future requirements and a huge number of decoupling capacitors, mainly due to the presence of parasitic inductance between the VRM and the microprocessor. In this paper, a new active damp concept is presented.
2. The Bulk Built In Current Sensor Approach for Single Event Transient Detection
E-print Network
Fayomi, Christian
Transients (SETs), are increasingly affecting the reliability of integrated circuits as device dimensions to store information has made integrated circuits more susceptible to energetic particle strikes]. As a consequence, efficient techniques to improve the reliability of integrated circuits against radiation effects
3. Overshoot effect in transient electroluminescence from single layer organic light-emitting diodes
J. Pommerehne; D. V. Nikolaenkov; V. R. Nikitenko; H. Bssler
2001-01-01
We investigate the transient electroluminescence (EL) from organic light-emitting diodes based on tristilbeneamine dispersed in polysulfone. An EL overshoot is observed a few microsecond after reversing the driving voltage. The amplitude of the EL spike can considerably exceed the previous EL level. The maximal EL intensity is strongly influenced by temperature, time duration of voltage pulse, and magnitude of reverse
4. Use of ruthenium dyes for subnanosecond detector fidelity testing in real time transient absorption
NASA Astrophysics Data System (ADS)
Byrdin, Martin; Thiagarajan, Viruthachalam; Villette, Sandrine; Espagne, Agathe; Brettel, Klaus
2009-04-01
Transient absorption spectroscopy is a powerful tool for the study of photoreactions on time scales from femtoseconds to seconds. Typically, reactions slower than 1 ns are recorded by the "classical" technique; the reaction is triggered by an excitation flash, and absorption changes accompanying the reaction are recorded in real time using a continuous monitoring light beam and a detection system with sufficiently fast response. The pico- and femtosecond region can be accessed by the more recent "pump-probe" technique, which circumvents the difficulties of real time detection on a subnanosecond time scale. This is paid for by accumulation of an excessively large number of shots to sample the reaction kinetics. Hence, it is of interest to extend the classical real time technique as far as possible to the subnanosecond range. In order to identify and minimize detection artifacts common on a subnanosecond scale, like overshoot, ringing, and signal reflections, rigorous testing is required of how the detection system responds to fast changes of the monitoring light intensity. Here, we introduce a novel method to create standard signals for detector fidelity testing on a time scale from a few picoseconds to tens of nanoseconds. The signals result from polarized measurements of absorption changes upon excitation of ruthenium complexes {[Ru(bpy)3]2+ and a less symmetric derivative} by a short laser flash. Two types of signals can be created depending on the polarization of the monitoring light with respect to that of the excitation flash: a fast steplike bleaching at magic angle and a monoexponentially decaying bleaching for parallel polarizations. The lifetime of the decay can be easily varied via temperature and viscosity of the solvent. The method is applied to test the performance of a newly developed real time transient absorption setup with 300 ps time resolution and high sensitivity.
5. Matrix laser vibrometer for transient modal imaging and rapid nondestructive testing
NASA Astrophysics Data System (ADS)
Kilpatrick, James M.; Markov, Vladimir
2008-06-01
This article describes the development and application of a 16x16 array (matrix) laser vibrometer based on a parallel architecture which supports fast 2D measurement of arbitrary (steady state, non-steady state, transient) solid body vibrations without beam scanning. The small size and low weight of the measurement probe, which is linked to a remote detector/processor unit via a flexible armoured fibre-optic umbilical, enables deployment in areas with restricted access. Incorporating aspects of high-speed electronic speckle pattern interferometry (ESPI) and laser Doppler vibrometry (LDV), the design is based on a hybrid fiber-optic/bulk optic interferometer which operates at a wavelength of 1550 nm. Test data illustrate high-speed capture of transient vibrations, showing the full 2D temporal evolution of surface deformation, including multiple resonant modes, of a center-pinned metal plate excited by a 1-50 kHz frequency chirp of 109 ms duration. We discuss preliminary data showing detection of sub-surface defects in composite materials, based on non-contact (frequency chirped) acoustic resonance of the locally damaged structure. For large area NDT the probe can be mounted on a lightweight XY gantry for automated multi-frame measurements.
6. Selecting single model in combination forecasting based on cointegration test and encompassing test.
PubMed
Jiang, Chuanjin; Zhang, Jing; Song, Fugen
2014-01-01
Combination forecasting takes all characters of each single forecasting method into consideration, and combines them to form a composite, which increases forecasting accuracy. The existing researches on combination forecasting select single model randomly, neglecting the internal characters of the forecasting object. After discussing the function of cointegration test and encompassing test in the selection of single model, supplemented by empirical analysis, the paper gives the single model selection guidance: no more than five suitable single models can be selected from many alternative single models for a certain forecasting target, which increases accuracy and stability. PMID:24892061
7. Selecting Single Model in Combination Forecasting Based on Cointegration Test and Encompassing Test
PubMed Central
Jiang, Chuanjin; Zhang, Jing; Song, Fugen
2014-01-01
Combination forecasting takes all characters of each single forecasting method into consideration, and combines them to form a composite, which increases forecasting accuracy. The existing researches on combination forecasting select single model randomly, neglecting the internal characters of the forecasting object. After discussing the function of cointegration test and encompassing test in the selection of single model, supplemented by empirical analysis, the paper gives the single model selection guidance: no more than five suitable single models can be selected from many alternative single models for a certain forecasting target, which increases accuracy and stability. PMID:24892061
8. Impacts Analyses Supporting the National Environmental Policy Act Environmental Assessment for the Resumption of Transient Testing Program
SciTech Connect
Annette L. Schafer; Lloyd C. Brown; David C. Carathers; Boyd D. Christensen; James J. Dahl; Mark L. Miller; Cathy Ottinger Farnum; Steven Peterson; A. Jeffrey Sondrup; Peter V. Subaiya; Daniel M. Wachs; Ruth F. Weiner
2013-11-01
Environmental and health impacts are presented for activities associated with transient testing of nuclear fuel and material using two candidate test reactors. Transient testing involves irradiation of nuclear fuel or materials for short time-periods under high neutron flux rates. The transient testing process includes transportation of nuclear fuel or materials inside a robust shipping cask to a hot cell, removal from the shipping cask, pre-irradiation examination of the nuclear materials, assembly of an experiment assembly, transportation of the experiment assembly to the test reactor, irradiation in the test reactor, transport back to the hot cell, and post-irradiation examination of the nuclear fuel or material. The potential for environmental or health consequences during the transportation, examination, and irradiation actions are assessed for normal operations, off-normal (accident) scenarios, and transportation. Impacts to the environment (air, soil, and groundwater), are assessed during each phase of the transient testing process. This report documents the evaluation of potential consequences to the general public. This document supports the Environmental Assessment (EA) required by the U.S. National Environmental Policy Act (NEPA) (42 USC Subsection 4321 et seq.).
9. Modeling from Local to Subsystem Level Effects in Analog and Digital Circuits Due to Space Induced Single Event Transients
NASA Technical Reports Server (NTRS)
Perez, Reinaldo J.
2011-01-01
Single Event Transients in analog and digital electronics from space generated high energetic nuclear particles can disrupt either temporarily and sometimes permanently the functionality and performance of electronics in space vehicles. This work first provides some insights into the modeling of SET in electronic circuits that can be used in SPICE-like simulators. The work is then directed to present methodologies, one of which was developed by this author, for the assessment of SET at different levels of integration in electronics, from the circuit level to the subsystem level.
10. Transient Plume Model Testing Using LADEE Spacecraft Attitude Control System Operations
NASA Technical Reports Server (NTRS)
Woronowicz, M. S.
2010-01-01
The Lunar Atmosphere Dust Environment Explorer (LADEE) spacecraft is being designed for a mission featuring low altitude orbits of the Moon to take relevant ambient measurements before that environment becomes altered by future exploration activities. Instruments include a neutral mass spectrometer capable of measuring ambient species density levels below 100 molecules/cu cm. Coincidentally, with a favorable combination of spacecraft orientations, it is also possible to measure plume gases from LADEE attitude control system thruster operations as they are reflected from the daytime lunar surface and subsequently intercepted by the spacecraft as it orbits overhead. Under such circumstances, it may be possible to test a variety of properties and assumptions associated with various transient plume models or to infer certain aspects regarding lunar surface properties.
11. Compendium of Test Results of Recent Single Event Effect Tests Conducted by the Jet Propulsion Laboratory
NASA Technical Reports Server (NTRS)
McClure, Steven S.; Allen, Gregory R.; Irom, Farokh; Scheick, Leif Z.; Adell, Philippe C.; Miyahira, Tetsuo F.
2010-01-01
This paper reports heavy ion and proton-induced single event effect (SEE) results from recent tests for a variety of microelectronic devices. The compendium covers devices tested over the last two years by the Jet Propulsion Laboratory.
12. Impacts Analyses Supporting the National Environmental Policy Act Environmental Assessment for the Resumption of Transient Testing Program
SciTech Connect
Annette L. Schafer; LLoyd C. Brown; David C. Carathers; Boyd D. Christensen; James J. Dahl; Mark L. Miller; Cathy Ottinger Farnum; Steven Peterson; A. Jeffrey Sondrup; Peter V. Subaiya; Daniel M. Wachs; Ruth F. Weiner
2014-02-01
This document contains the analysis details and summary of analyses conducted to evaluate the environmental impacts for the Resumption of Transient Fuel and Materials Testing Program. It provides an assessment of the impacts for the two action alternatives being evaluated in the environmental assessment. These alternatives are (1) resumption of transient testing using the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory (INL) and (2) conducting transient testing using the Annular Core Research Reactor (ACRR) at Sandia National Laboratory in New Mexico (SNL/NM). Analyses are provided for radiologic emissions, other air emissions, soil contamination, and groundwater contamination that could occur (1) during normal operations, (2) as a result of accidents in one of the facilities, and (3) during transport. It does not include an assessment of the biotic, cultural resources, waste generation, or other impacts that could result from the resumption of transient testing. Analyses were conducted by technical professionals at INL and SNL/NM as noted throughout this report. The analyses are based on bounding radionuclide inventories, with the same inventories used for test materials by both alternatives and different inventories for the TREAT Reactor and ACRR. An upper value on the number of tests was assumed, with a test frequency determined by the realistic turn-around times required between experiments. The estimates provided for impacts during normal operations are based on historical emission rates and projected usage rates; therefore, they are bounding. Estimated doses for members of the public, collocated workers, and facility workers that could be incurred as a result of an accident are very conservative. They do not credit safety systems or administrative procedures (such as evacuation plans or use of personal protective equipment) that could be used to limit worker doses. Doses estimated for transportation are conservative and are based on transport of the bounding radiologic inventory that will be contained in any given test. The transportation analysis assumes all transports will contain the bounding inventory.
13. Single-sample decohesion test: mechanics and implementation
Mitul B. Modi; Suresh K. Sitaraman
2004-01-01
The Single-Sample Decohesion Test (SSDT), developed by the authors, eliminates shortcomings of current interfacial fracture toughness testing methods. In this approach, a highly stressed super layer is used to drive delamination and create any mode mix at the crack tip. SSDT uses the change in crack surface area to vary the available energy per unit area for crack growth and
14. Experimental test of nonclassicality for a single particle
E-print Network
G. Brida; I. Degiovanni; M. Genovese; V. Schettini; S. Polyakov; A. Migdall
2008-04-10
In a recent paper [R. Alicki and N. Van Ryn, J. Phys. A: Math. Theor., 41, 062001 (2008)] a test of nonclassicality for a single qubit was proposed. Here, we discuss the class of local realistic theories to which this test applies and present an experimental realization.
15. Tensile testing of a single ultrafine polymeric fiber
E. P. S. Tan; S. Y. Ng; C. T. Lim
2005-01-01
Due to the difficulty in handling micro and nanoscale fibers and measuring the small load required for deformation, mechanical properties of these fibers have not been widely characterized. In this study, tensile test of a single-strand polycaprolactone electrospun ultrafine fiber was performed using a nano tensile tester. The tested fiber exhibited the characteristic low strength and low modulus but high
16. Dynamics and transient absorption spectral signatures of the single-wall carbon nanotube electronically excited triplet state.
PubMed
Park, Jaehong; Deria, Pravas; Therien, Michael J
2011-11-01
We utilize femtosecond-to-microsecond time domain pump-probe transient absorption spectroscopy to interrogate for the first time the electronically excited triplet state of individualized single-wall carbon nanotubes (SWNTs). These studies exploit (6,5) chirality-enriched SWNT samples and poly[2,6-{1,5-bis(3-propoxysulfonic acid sodium salt)}naphthylene]ethynylene (PNES), which helically wraps the nanotube surface with periodic and constant morphology (pitch length = 10 2 nm), providing a self-assembled superstructure that maintains structural homogeneity in multiple solvents. Spectroscopic interrogation of such PNES-SWNT samples in aqueous and DMSO solvents using E(22) excitation and a white-light continuum probe enables E(11) and E(22) spectral evolution to be monitored concomitantly. Such experiments not only reveal classic SWNT singlet exciton relaxation dynamics and transient absorption signatures but also demonstrate spectral evolution consistent with formation of a triplet exciton state. Transient dynamical studies evince that (6,5) SWNTs exhibit rapid S(1)?T(1) intersystem crossing (ISC) (?(ISC) ~20 ps), a sharp T(1)?T(n) transient absorption signal (?(max)(T(1)?T(n)) = 1150 nm; full width at half-maximum ? 350 cm(-1)), and a substantial T(1) excited-state lifetime (?(es) ? 15 ?s). Consistent with expectations for a triplet exciton state, T(1)-state spectral signatures and T(1)-state formation and decay dynamics for PNES-SWNTs in aqueous and DMSO solvents, as well as those determined for benchmark sodium cholate suspensions of (6,5) SWNTs, are similar; likewise, studies that probe the (3)[(6,5) SWNT]* state in air-saturated solutions demonstrate (3)O(2) quenching dynamics reminiscent of those determined for conjugated aromatic hydrocarbon excited triplet states. PMID:21970339
17. Loss-of-feedwater, steam generator tube rupture, and steam line break experiments: Steam generator transient response test program: Interim report
O. J. Mendler; K. Takeuchi; M. Y. Young
1987-01-01
The Westinghouse Model Boiler No. 2 (MB-2) steam generator test model at the Engineering Test Facility in Tampa, Florida, was reinstrumented and modified for performing a series of tests simulating steam generator accident transients. The transients simulated were: loss of feed flow, steam generator tube rupture, and steam line break events. This document presents a description of (1) the model
18. High-throughput testing of terpenoid biosynthesis candidate genes using transient expression in Nicotiana benthamiana.
PubMed
Bach, Sren Spanner; Bassard, Jean-tienne; Andersen-Ranberg, Johan; Mldrup, Morten Emil; Simonsen, Henrik Toft; Hamberger, Bjrn
2014-01-01
To respond to the rapidly growing number of genes putatively involved in terpenoid metabolism, a robust high-throughput platform for functional testing is needed. An in planta expression system offers several advantages such as the capacity to produce correctly folded and active enzymes localized to the native compartments, unlike microbial or prokaryotic expression systems. Two inherent drawbacks of plant-based expression systems, time-consuming generation of transgenic plant lines and challenging gene-stacking, can be circumvented by transient expression in Nicotiana benthamiana. In this chapter we describe an expression platform for rapid testing of candidate terpenoid biosynthetic genes based on Agrobacterium mediated gene expression in N. benthamiana leaves. Simultaneous expression of multiple genes is facilitated by co-infiltration of leaves with several engineered Agrobacterium strains, possibly making this the fastest and most convenient system for the assembly of plant terpenoid biosynthetic routes. Tools for cloning of expression plasmids, N. benthamiana culturing, Agrobacterium preparation, leaf infiltration, metabolite extraction, and automated GC-MS data mining are provided. With all steps optimized for high throughput, this in planta expression platform is particularly suited for testing large panels of candidate genes in all possible permutations. PMID:24777803
19. Anomalous transient uplift observed at the Lop Nor, China nuclear test site using satellite radar interferometry time-series analysis
NASA Astrophysics Data System (ADS)
Vincent, P.; Buckley, S. M.; Yang, D.; Carle, S. F.
2011-12-01
Anomalous uplift is observed at the Lop Nor, China nuclear test site using ERS satellite SAR data. Using an InSAR time-series analysis method, we show that an increase in absolute uplift with time is observed between 1997 and 1999. The signal is collocated with past underground nuclear tests. Due to the collocation in space with past underground tests we postulate a nuclear test-related hydrothermal source for the uplift signal. A possible mechanism is presented that can account for the observed transient uplift and is consistent with documented thermal regimes associated with underground nuclear tests conducted at the Nevada National Security Site (NNSS) (formerly the Nevada Test Site).
20. High-Speed Single-Event Current Transient Measurements in SiGe HBTs
NASA Technical Reports Server (NTRS)
Pellish, Jonathan A.; Reed, R.A.; McMorrow, D.; Vizkelethy, G.; Ferlet-Cavrois, V.; Baggio, J.; Paillet, P.; Duhamel, O.; Phillips, S.D.; Sutton, A.K.; Diestelhorst, R.M.; Cressler, J.D.; Dodd, P.E.; Pate, N.D.; Alles, M.L.; Schrimpf, R.D.; Marshall, P.W.; LaBel, K.A.
2009-01-01
Time-resolved ion beam induced charge reveals heavy ion response of IBM 5AM SiGe HBT: 1) Position correlation. 2) Unique response for different bias schemes. 3) Similarities to TPA pulsed-laser data. Heavy ion broad-beam transients provide more realistic device response: 1) Feedback using microbeam data 2) Overcome existing issues of LET and ion range with microbeam Both micro- and broad-beam data sets yield valuable input for TCAD simulations. Uncover detailed mechanisms for SiGe HBTs and other devices fabricated on lightly-doped substrates.
1. Issues for single-event proton testing of SRAMs
J. R. Schwank; P. E. Dodd; M. R. Shaneyfelt; J. A. Felix; G. L. Hash; V. Ferlet-Cavrois; P. Paillet; J. Baggio; P. Tangyunyong; E. Blackmore
2004-01-01
The impact of total ionizing dose and displacement damage on single-event upset and single-event latchup hardness assurance testing of present-day commercial SRAMs is studied over a wide range of proton energies and fluence levels. Commercial SRAMs from six different vendors were irradiated at proton energies from 8 to 500 MeV and at total doses from 0 to 100 krad(Si) using
2. Single Event Transient Response of SiGe Voltage References and Its Impact on the Performance of Analog and Mixed-Signal Circuits
Laleh Najafizadeh; Stanley D. Phillips; Kurt A. Moen; Ryan M. Diestelhorst; Marco Bellini; Prabir K. Saha; John D. Cressler; Gyorgy Vizkelethy; Marek Turowski; Ashok Raman; Paul W. Marshall
2009-01-01
We investigate the single-event transient (SET) response of bandgap voltage references (BGRs) implemented in SiGe BiCMOS technology through heavy ion microbeam experiments. The SiGe BGR circuit is used to provide the input reference voltage to a voltage regulator. SiGe HBTs in the BGR circuit are struck with 36-MeV oxygen ions, and the subsequent transient responses are captured at the output
3. Selective isolation of transiently transfected cells from a mammalian cell population with vectors expressing a membrane anchored single-chain antibody
Jonathan D. Chesnut; Apollo R. Baytan; Marijane Russell; Mei-Ping Chang; Amy Bernard; Ian H. Maxwell; James P. Hoeffler
1996-01-01
We present here a novel technology for the rapid selection of transiently transfected cells from total populations in culture. This system utilizes recombinant antibody technology to produce a molecular hook by displaying a hapten-binding single-chain antibody (sFv) on the surface of transfected cells. Mammalian cell lines from several origins were transiently transfected with a plasmid (pHook-1) that encodes an sFv
4. Pre-flight transient dynamic analysis of B-52 carrying Space Shuttle solid rocket booster drop-test vehicle
NASA Technical Reports Server (NTRS)
Ko, W. L.; Schuster, L. S.
1983-01-01
This paper concerns the transient dynamic analysis of the B-52 aircraft carrying the Space Shuttle solid-rocket booster drop-test vehicle (SRB/DTV). The NASA structural analysis (NASTRAN) finite-element computer program was used in the analysis. The B-52 operating conditions considered for analysis were (1) landing and (2) braking on aborted takeoff runs. The transient loads for the B-52 pylon front and rear hooks were calculated. The results can be used to establish the safe maneuver envelopes for the B-52 carrying the SRB/DTV in landings and brakings.
5. Preflight transient dynamic analyses of B-52 aircraft carrying Space Shuttle solid rocket booster drop-test vehicle
NASA Technical Reports Server (NTRS)
Ko, W. L.; Schuster, L. S.
1984-01-01
This paper concerns the transient dynamic analysis of the B-52 aircraft carrying the Space Shuttle solid rocket booster drop test vehicle (SRB/DTV). The NASA structural analysis (NASTRAN) finite element computer program was used in the analysis. The B-52 operating conditions considered for analysis were (1) landing and (2) braking on aborted takeoff runs. The transient loads for the B-52 pylon front and rear hooks were calculated. The results can be used to establish the safe maneuver envelopes for the B-52 carrying the SRB/DTV in landings and brakings.
6. Single-antigen serological testing for bovine tuberculosis.
PubMed
Green, Lawrence R; Jones, Cynthia C; Sherwood, Anne L; Garkavi, Inna V; Cangelosi, Gerard A; Thacker, Tyler C; Palmer, Mitchell V; Waters, W Ray; Rathe, Chris V
2009-09-01
Antibody responses are useful indicators of Mycobacterium bovis infection of cattle. Tests for such responses often use multiple M. bovis antigens as detection probes. This is recommended because responses to single antigens may be too variable for consistent diagnosis. However, the use of multiple antigens increases costs and the risk of false-positive results. As an alternative, the SeraLyte-Mbv system detects responses to a single M. bovis antigen, MPB83, by using a chemiluminescent testing platform with a high degree of analytical sensitivity. Testing with the SeraLyte-Mbv system was conducted in a blinded fashion with sera from experimentally infected and control cattle. To assess the species specificity of the single-antigen test, the sample included sera from animals infected with M. bovis (n = 27), M. kansasii (n = 4), M. avium subsp. paratuberculosis (n = 11), M. avium subsp. avium (n = 12), and uninfected animals (n = 15). Upon unblinding of the results, the sensitivity of the SeraLyte-Mbv system relative to the results for animals with known M. bovis infection was 89%. Consistent with the conservation of MPB83 sequences within the genus Mycobacterium, all 4 M. kansasii-infected animals tested positive with the SeraLyte-Mbv system and all 23 M. avium-infected animals tested negative. Blinded analysis of 30 serum samples collected from nine animals at various time points postinfection indicated 100% sensitivity after > or = 3 months postinfection. All 15 uninfected samples in the blinded sample set tested negative with the SeraLyte-Mbv system. Unblinded analysis of sera from an additional 895 animals in 10 accredited bovine tuberculosis-free states revealed 98% specificity overall. The results support the feasibility of single-antigen testing for bovine tuberculosis with the SeraLyte-Mbv system. PMID:19605596
7. Single event test methodology and test results of commercial gigabit per second Fiber Channel hardware
M. A. Carts; P. W. Marshall; C. J. Marshall; K. A. Label; M. Flanegan; J. Bretthauer
1997-01-01
This article presents a detailed description of the single event test methods used to evaluate two different component sets conforming to the Fiber Channel (FC) commercial high-speed serial bus standard. The devices tested perform the hierarchically low-level functions such as transmission coding and actual electrical or optical linking. Pertinent portions of the FC specification, and details of the test setup
8. Single-inductor, multiple-output buck converter with parallel source transient recovery
E-print Network
King, Charles Jackson, III
2009-01-01
To address the need for multiple regulated voltage supplies in electronic devices, this thesis presents a modeling and design study of a single-inductor, multiple-output (SIMO) DC-DC buck converter with parallel source ...
9. Transient and Steady-state Tests of the Space Power Research Engine with Resistive and Motor Loads
NASA Technical Reports Server (NTRS)
Rauch, Jeffrey S.; Kankam, M. David
1995-01-01
The NASA Lewis Research Center (LeRC) has been testing free-piston Stirling engine/linear alternators (FPSE/LA) to develop advanced power convertors for space-based electrical power generation. Tests reported herein were performed to evaluate the interaction and transient behavior of FPSE/LA-based power systems with typical user loads. Both resistive and small induction motor loads were tested with the space power research engine (SPRE) power system. Tests showed that the control system could maintain constant long term voltage and stable periodic operation over a large range of engine operating parameters and loads. Modest resistive load changes were shown to cause relatively large voltage and, therefore, piston and displacer amplitude excursions. Starting a typical small induction motor was shown to cause large and, in some cases, deleterious voltage transients. The tests identified the need for more effective controls, if FPSE/LAs are to be used for stand-alone power systems. The tests also generated a large body of transient dynamic data useful for analysis code validation.
10. April 24, 2001 Radiation Tests for Single Event Effects
E-print Network
.2 109 2.6 1010 (5.66 1010 max) Mezzanine Card 7.00 109 3.5 1010 ADC integrator 2.80 109 1-mail: [email protected], [email protected] Proton irradiation tests for single event effects
11. Quantitative EEG is an objective, sensitive, and reliable indicator of transient anesthetic effects during Wada tests.
PubMed
Tu, Bin; Assassi, Nadege J; Bazil, Carl W; Hamberger, Marla J; Hirsch, Lawrence J
2015-04-01
The intracarotid amobarbital or Wada procedure is a component of the presurgical evaluation for refractory epilepsy, during which monitoring the onset and offset of transient anesthetic effects is critical. In this study, the authors characterized changes of 8 quantitative measures during 26 Wada tests, which included alpha, beta, theta, and delta powers, alpha/delta power ratio, beta/delta power ratio, median amplitude-integrated EEG, and 90% spectral edge frequency (SEF90), and correlated them with contralateral hemiplegia. The authors found that on the side of injection, delta and theta powers, alpha/delta power ratio, beta/delta power ratio, and SEF90 peaked within 1 minute after injection of 70 to 150 mg amobarbital or 4 to 7 mg methohexital. When contralateral arm strength returned to 3/5, delta power and amplitude-integrated EEG decayed on average 24% and 19%, respectively, for amobarbital, similar to that of methohexital (27% and 18%). Because delta power resolution most closely mirrored that of the hemiplegia and amplitude-integrated EEG had the highest signal/noise ratio, these quantitative values appear to be the best measures for decay of anesthetic effects. Increase in alpha power persisted longest, and therefore may be the best measure of late residual anesthetic effects. PMID:25580802
12. Dark current transients in HgI2 single crystals used as ?- and x-ray spectrometers
NASA Astrophysics Data System (ADS)
Levi, A.; Schieber, M. M.; Burshtein, Z.
1985-03-01
Transient characteristics of dark currents have been measured in HgI2 single crystals as functions of voltage and temperature. The existence of a hole trapping center, 0.7 eV deep and of density 1015 cm-3, was established, which effectively lowers the hole drift mobility by about seven orders of magnitude. The samples were found to be slightly extrinsic n type, the Fermi level being 0.9 eV deep. The room-temperature electron density was about 2103 cm-3. The meaning of these characteristics to the performances of HgI2 ?- and x-ray spectrometers is discussed. Particularly, it is suggested that lowering of the HgI2 detector operation temperature to about 0 C will improve its energy resolution capabilities.
13. COMMIX-1AR/P: A three-dimensional transient single-phase computer program for thermal hydraulic analysis of single and multicomponent systems
SciTech Connect
Garner, P.L.; Blomquist, R.N.; Gelbard, E.M.
1992-09-01
The COMMIX-1AR/P computer program is designed for analyzing the steady-state and transient aspects of single-phase fluid flow and heat transfer in three spatial dimensions. This version is an extension of the modeling in COMMIX-1A to include multiple fluids in physically separate regions of the computational domain, modeling descriptions for pumps, radiation heat transfer between surfaces of the solids which are embedded in or surround the fluid, a k-[var epsilon] model for fluid turbulence, and improved numerical techniques. The porous-medium formulation in COMMIX allows the program to be applied to a wide range of problems involving both simple and complex geometrical arrangements. The input preparation and execution procedures are presented for the COMMIX-1AR/P program and several postprocessor programs which produce graphical displays of the calculated results.
14. COMMIX-1AR/P: A three-dimensional transient single-phase computer program for thermal hydraulic analysis of single and multicomponent systems
SciTech Connect
Garner, P.L.; Blomquist, R.N.; Gelbard, E.M.
1992-09-01
The COMMIX-LAR/P computer program is designed for analyzing the steady-state and transient aspects of single-phase fluid flow and heat transfer in three spatial dimensions. This version is an extension of the modeling in COMMIX-lA to include multiple fluids in physically separate regions of the computational domain, modeling descriptions for pumps, radiation heat transfer between surfaces of the solids which are embedded in or surround the fluid, a keg model for fluid turbulence, and improved numerical techniques. The porous-medium formulation in COMMIX allows the program to be applied to a wide range of problems involving both simple and complex geometrical arrangements. The internal aspects of the COMMIX-LAR/P program are presented, covering descriptions of subprograms, variables, and files.
15. Transient memory effect in the photoluminescence of InGaN single quantum wells.
PubMed
Feldmeier, Christian; Abiko, Masayoshi; Schwarz, Ulrich T; Kawakami, Yoichi; Micheletto, Ruggero
2009-12-01
The transition to maximum photoluminescence of InGaN single quantum wells is a phenomena that has time constants in the range of few seconds. Using a systematic illumination/darkening procedure we found that these characteristics are related to previous stimulations as if the sample has a memory of past illumination events. Choosing opportune time sequences, time constants were observed to vary more than 100%. These facts suggest the presence of carrier trapping/de-trapping processes that act beyond the single illumination event, accumulating over time in a complex effect. PMID:20052211
16. A comparison of two single fibre interface tests
SciTech Connect
Baillie, C.; Kim, J.K.; Mai, Y.W. [Univ. of Sydney, NSW (Australia). Dept. of Mechanical Engineering
1993-12-31
Single fiber tests are often used to determine interfacial properties as they can directly monitor changes at the interface. However, analyses of these tests is still complex and very little work has been carried out on the comparison of results from one test type to another. In this paper the pull-out and fragmentation tests are used to measure properties of the interface between treated carbon fiber and epoxy resin. The results are analyzed to obtain shear strength values for the interface. The pull-out test generates two shear strength values, the first, a bond shear strength associated with initiation of a crack and the second a value for frictional shear strength in the debonded region. The fragmentation test, on the other hand, generates a mean value for the whole interface. The results from each test are compared and it is discovered that the maximum pull-out length L{sub max} is comparable to the mean fragment length measured by the fragmentation test for each fiber tested. Also the fragmentation generated mean shear strength values lie between the two pull-out values for each fiber treatment level tested, showing an increasing bias towards the bond shear strength value with increasing treatment level.
17. Testing consistency of deconfinement heating of strange stars in superbursters and soft X-ray transients
E-print Network
M. Stejner
2006-12-29
Both superbursters and soft X-ray transients probe the thermal structure of the crust on compact stars and are sensitive to the process of deep crustal heating. It was recently shown that the transfer of matter from crust to core in a strange star can heat the crust by deconfinement and ignite superbursts provided certain constraints on the strange quark matter equation of state are fulfilled. Corresponding constraints are derived for soft X-ray transients in a simple parameterized model assuming their quiescent emission is powered in the same way, and the time dependence of this heating mechanism in transient systems is discussed.
18. Pressure transient test analysis of vuggy naturally fractured carbonate reservoir: field case study
E-print Network
Ajayi, Babatunde Tolulope
2009-06-02
is to analyze, interpret and categorize the pressure transient responses obtained from 22 wells in a vuggy naturally fractured carbonate reservoir in an attempt to understand the heterogeneities of the porosity system. Different modeling techniques useful...
19. Impact of transient single-phase heat transfer modeling on predicted BWR fuel stability margins
R. P. Taleyarkhan; A. F. McFarlane; M. Z. Podowski; R. T. Jr. Lahey
1987-01-01
Boiling flow instabilities must be considered in the design and analysis of many devices in energy production, e.g., boiling water nuclear reactors (BWRs). The most common thermal-hydraulic instability mechanism of interest to BWR operation in known as density-wave oscillations. An important aspect of analytically investigating density-wave oscillations deals with heater wall dynamic modeling in the single- and two-phase regions, respectively.
20. Forever alone? Testing single eccentric planetary systems for multiple companions
E-print Network
Wittenmyer, Robert A; Horner, Jonathan; Tinney, C G; Butler, R P; Jones, H R A; O'Toole, S J; Bailey, J; Carter, B D; Salter, G S; Wright, D
2013-01-01
Determining the orbital eccentricity of an extrasolar planet is critically important for understanding the system's dynamical environment and history. However, eccentricity is often poorly determined or entirely mischaracterized due to poor observational sampling, low signal-to-noise, and/or degeneracies with other planetary signals. Some systems previously thought to contain a single, moderate-eccentricity planet have been shown, after further monitoring, to host two planets on nearly-circular orbits. We investigate published apparent single-planet systems to see if the available data can be better fit by two lower-eccentricity planets. We identify nine promising candidate systems and perform detailed dynamical tests to confirm the stability of the potential new multiple-planet systems. Finally, we compare the expected orbits of the single- and double-planet scenarios to better inform future observations of these interesting systems.
1. Forever Alone? Testing Single Eccentric Planetary Systems for Multiple Companions
NASA Astrophysics Data System (ADS)
Wittenmyer, Robert A.; Wang, Songhu; Horner, Jonathan; Tinney, C. G.; Butler, R. P.; Jones, H. R. A.; O'Toole, S. J.; Bailey, J.; Carter, B. D.; Salter, G. S.; Wright, D.; Zhou, Ji-Lin
2013-09-01
Determining the orbital eccentricity of an extrasolar planet is critically important for understanding the system's dynamical environment and history. However, eccentricity is often poorly determined or entirely mischaracterized due to poor observational sampling, low signal-to-noise, and/or degeneracies with other planetary signals. Some systems previously thought to contain a single, moderate-eccentricity planet have been shown, after further monitoring, to host two planets on nearly circular orbits. We investigate published apparent single-planet systems to see if the available data can be better fit by two lower-eccentricity planets. We identify nine promising candidate systems and perform detailed dynamical tests to confirm the stability of the potential new multiple-planet systems. Finally, we compare the expected orbits of the single- and double-planet scenarios to better inform future observations of these interesting systems.
2. FOREVER ALONE? TESTING SINGLE ECCENTRIC PLANETARY SYSTEMS FOR MULTIPLE COMPANIONS
SciTech Connect
Wittenmyer, Robert A.; Horner, Jonathan; Tinney, C. G.; Bailey, J.; Salter, G. S.; Wright, D. [Department of Astrophysics, School of Physics, Faculty of Science, The University of New South Wales, Sydney, NSW 2052 (Australia); Wang Songhu; Zhou Jilin [Department of Astronomy and Key Laboratory of Modern Astronomy and Astrophysics in Ministry of Education, Nanjing University, Nanjing 210093 (China); Butler, R. P. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015-1305 (United States); Jones, H. R. A. [University of Hertfordshire, Centre for Astrophysics Research, Science and Technology Research Institute, College Lane, AL10 9AB Hatfield (United Kingdom); O'Toole, S. J. [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); Carter, B. D., E-mail: [email protected] [Faculty of Sciences, University of Southern Queensland, Toowoomba, Queensland 4350 (Australia)
2013-09-15
Determining the orbital eccentricity of an extrasolar planet is critically important for understanding the system's dynamical environment and history. However, eccentricity is often poorly determined or entirely mischaracterized due to poor observational sampling, low signal-to-noise, and/or degeneracies with other planetary signals. Some systems previously thought to contain a single, moderate-eccentricity planet have been shown, after further monitoring, to host two planets on nearly circular orbits. We investigate published apparent single-planet systems to see if the available data can be better fit by two lower-eccentricity planets. We identify nine promising candidate systems and perform detailed dynamical tests to confirm the stability of the potential new multiple-planet systems. Finally, we compare the expected orbits of the single- and double-planet scenarios to better inform future observations of these interesting systems.
3. Testing for new physics in singly Cabibbo suppressed D decays
E-print Network
Yuval Grossman; Alexander L. Kagan; Jure Zupan
2012-04-16
We devise tests for a new physics origin of the recently measured direct CP violation in singly Cabibbo suppressed D decays. The tests take the form of sum rules for the CP asymmetries in various D decays. They are based on the fact that within the standard model CP violation arises from interference of the dominant tree amplitudes with the Delta I=1/2 penguin amplitudes. The sum rules would be violated if the observed CP violation is due to new physics contributions to the effective weak Hamiltonian that change isospin by Delta I=3/2.
4. Single-qubit tests of Bell-like inequalities
SciTech Connect
Zela, F. de [Departamento de Ciencias, Seccion Fisica Pontificia, Universidad Catolica del Peru, Apartado 1761, Lima (Peru)
2007-10-15
This paper discusses some tests of Bell-like inequalities not requiring entangled states. The proposed tests are based on consecutive measurements on a single qubit. Available hidden-variable models for a single qubit [see, e.g., J. S. Bell, Rev. Mod. Phys. 38, 447 (1966)] reproduce the predictions of quantum mechanics and hence violate the Bell-like inequalities addressed in this paper. It is shown how this fact is connected with the state 'collapse' and with its random nature. Thus, it becomes possible to test truly realistic and deterministic hidden-variable models. In this way, it can be shown that a hidden-variable model should entail at least one of the following features: (i) nonlocality, (ii) contextuality, or (iii) discontinuous measurement-dependent probability functions. The last two features are put to the test with the experiments proposed in this paper. A hidden-variable model that is noncontextual and deterministic would be at variance with some predictions of quantum mechanics. Furthermore, the proposed tests are more likely to be loophole-free, as compared to former ones.
5. Experimental verification of the parasitic bipolar amplification effect in PMOS single event transients
NASA Astrophysics Data System (ADS)
He, Yi-Bai; Chen, Shu-Ming
2014-07-01
The contribution of parasitic bipolar amplification to SETs is experimentally verified using two P-hit target chains in the normal layout and in the special layout. For PMOSs in the normal layout, the single-event charge collection is composed of diffusion, drift, and the parasitic bipolar effect, while for PMOSs in the special layout, the parasitic bipolar junction transistor cannot turn on. Heavy ion experimental results show that PMOSs without parasitic bipolar amplification have a 21.4% decrease in the average SET pulse width and roughly a 40.2% reduction in the SET cross-section.
6. COMMIX-1C: A three-dimensional transient single-phase computer program for thermal-hydraulic analysis of single-component and multicomponent engineering systems
SciTech Connect
Domanus, H.M.; Cha, Y.S.; Chien, T.H.; Schmitt, R.C.; Sha, W.T. (Argonne National Lab., IL (USA))
1990-11-01
The COMMIX-1C computer program is an extended and improved version of previous COMMIX codes with four major additions or modifications: (1) a new finite-volume formulation for the mass, momentum, and energy equations to extend the applications to subsonic compressible flows and to make the calculations more robust; (2) a flow-modulated skew-upwind discretization scheme to reduce numerical diffusion; (3) two new matrix solvers for the discretized equations to increase the flexibility and efficiency of numerical computation; and (4) a k-{var epsilon} two-equation turbulence model that is more robust and better validated than those in previous COMMIX codes. In addition, there are numerous smaller modifications that improve overall operation greatly. COMMIX-1C solves the conservation equations of mass, momentum, and energy, as well as the transport equations of turbulence parameters. It is designed to perform steady-state/transient, single-phase, three-dimensional analysis of fluid flow with heat transfer in a single-component or a multicomponent engineering system. The program was developed for the analysis of heat transfer and fluid flow processes in a nuclear reactor system. However, it is designed in a generalized fashion so that, with little or no modifications, it can be used to analyze processes in any engineering equipment or in any system. This document, Volume II (User's Guide and Manual), contains the input instruction, sample problems, flow charts, and description of available options and boundary conditions. 25 figs., 17 tabs.
7. Instrumented Taylor anvil-on-rod impact tests for validating applicability of standard strength models to transient deformation states
NASA Astrophysics Data System (ADS)
Eakins, D. E.; Thadhani, N. N.
2006-10-01
Instrumented Taylor anvil-on-rod impact tests have been conducted on oxygen-free electronic copper to validate the accuracy of current strength models for predicting transient states during dynamic deformation events. The experiments coupled the use of high-speed digital photography to record the transient deformation states and laser interferometry to monitor the sample back (free surface) velocity as a measure of the elastic/plastic wave propagation through the sample length. Numerical continuum dynamics simulations of the impact and plastic wave propagation employing the Johnson-Cook [Proceedings of the Seventh International Symposium on Ballistics, 1983, The Netherlands (Am. Def. Prep. Assoc. (ADPA)), pp. 541-547], Zerilli-Armstrong [J. Appl. Phys. C1, 1816 (1987)], and Steinberg-Guinan [J. Appl. Phys. 51, 1498 (1980)] constitutive equations were used to generate transient deformation profiles and the free surface velocity traces. While these simulations showed good correlation with the measured free surface velocity traces and the final deformed sample shape, varying degrees of deviations were observed between the photographed and calculated specimen profiles at intermediate deformation states. The results illustrate the usefulness of the instrumented Taylor anvil-on-rod impact technique for validating constitutive equations that can describe the path-dependent deformation response and can therefore predict the transient and final deformation states.
8. A one-dimensional transient model of a single-stage, downward-firing entrained-flow gasifier
SciTech Connect
Kasule, J.; Turton, R.; Bhattacharyya, D.; Zitney, S.
2012-01-01
The integrated gasification combined cycle (IGCC) technology has emerged as an attractive alternative to conventional coal-fired power plant technology due to its higher efficiency and cleaner environmental performance especially with the option of CO{sub 2} capture and sequestration. The core unit of this technology is the gasifier whose optimal performance must be understood for efficient operation of IGCC power plants. This need has led a number of researchers to develop gasifier models of varying complexities. Whereas high-fidelity CFD models can accurately predict most key aspects of gasifier performance, they are computationally expensive and typically take hours to days to execute on high-performance computers. Therefore, faster one-dimensional (1D) partial differential equation (PDE)-based models are required for use in dynamic simulation studies, control system analysis, and training applications. A number of 1D gasifier models can be found in the literature, but most are steady-state and have limited application in the practical operation of the gasifier. As a result, 1D PDE-based dynamic models are needed to further study and predict gasifier performance under a wide variety of process conditions and disturbances. In the present study, a 1D transient model of a single-stage downward flow GE/Texaco-type gasifier has been developed. The model comprises mass, momentum and energy balances for the gas and solid phases. The model considers the initial gasification processes of water evaporation and coal devolatilization. In addition, the key heterogeneous and homogeneous chemical reactions have been modeled. The resulting time-dependent PDE model is solved using the well-known method of lines approach in Aspen Custom Modeler, whereby the PDEs are discretized in the spatial domain and the resulting differential algebraic equations (DAEs) are then solved to obtain the transient response. The transient response of various gasifier performance parameters to certain disturbances commonly encountered in the real world operation of commercial IGCC plants will be presented. These disturbances include ramp and step changes in input variables such as coal flow rate, oxygen-to-coal ratio and water-to-coal ratio, among others. Comparison of gasifier model predictions to available dynamic data will also be discussed.
9. Calcium transients during early development in single starfish (Asterias forbesi) oocytes
SciTech Connect
Eisen, A.; Reynolds, G.T.
1984-11-01
Maturation and fertilization of the starfish oocyte are putative calcium-dependent events. The authors have investigated the spatial distribution and temporal dynamics of this calcium dependence in single oocytes of Asterias forbesi. They used the calcium photoprotein, aequorin, in conjunction with a microscope-photomultiplier and microscope-image intensifier. Surprisingly, in contrast to earlier work with Marasthenias glacialis, there is no detectable increase in intracellular-free calcium in the oocyte of A. forbesi in response to the maturation hormone 1-methyl adenine. During fertilization of the same, matured, A. forbesi oocyte there is a large increase in intracellular-free calcium. The calcium concentration increases to approx.1 ..mu..M at the point of insemination and the region of elevated free calcium expands across the oocyte in approx.20 s (17-19/sup 0/C). After the entire oocyte reaches an elevated concentration of free calcium, the concentration decreases uniformly throughout the oocyte over the next several minutes.
10. Global nuclear energy partnership fuels transient testing at the Sandia National Laboratories nuclear facilities : planning and facility infrastructure options.
SciTech Connect
Kelly, John E.; Wright, Steven Alan; Tikare, Veena; MacLean, Heather J. (Idaho National Laboratory, Idaho Falls, ID); Parma, Edward J., Jr.; Peters, Curtis D.; Vernon, Milton E.; Pickard, Paul S.
2007-10-01
The Global Nuclear Energy Partnership fuels development program is currently developing metallic, oxide, and nitride fuel forms as candidate fuels for an Advanced Burner Reactor. The Advance Burner Reactor is being designed to fission actinides efficiently, thereby reducing the long-term storage requirements for spent fuel repositories. Small fuel samples are being fabricated and evaluated with different transuranic loadings and with extensive burnup using the Advanced Test Reactor. During the next several years, numerous fuel samples will be fabricated, evaluated, and tested, with the eventual goal of developing a transmuter fuel database that supports the down selection to the most suitable fuel type. To provide a comparative database of safety margins for the range of potential transmuter fuels, this report describes a plan to conduct a set of early transient tests in the Annular Core Research Reactor at Sandia National Laboratories. The Annular Core Research Reactor is uniquely qualified to perform these types of tests because of its wide range of operating capabilities and large dry central cavity which extents through the center of the core. The goal of the fuels testing program is to demonstrate that the design and fabrication processes are of sufficient quality that the fuel will not fail at its design limit--up to a specified burnup, power density, and operating temperature. Transient testing is required to determine the fuel pin failure thresholds and to demonstrate that adequate fuel failure margins exist during the postulated design basis accidents.
11. Spray characteristics of single- and three-hole nozzle injectors in ambient air and in a motored single-cylinder test engine. Technical report
SciTech Connect
Hahn, J.P.; Hamady, F.J.; Schaefer, R.M.
1994-11-01
The high-speed/high-resolution imaging system was used to evaluate two mid-pressure (15 MPa) fuel injector nozzles in ambient air and in a motored single-cylinder test engine. The nozzles are designed for use in the EPA/NVFEL program to develop clean and efficient engines that use alternative fuels. The report is part of an ongoing investigation to analyze the transient spray characteristics for direct-injection type fuel injectors. The experimental results compare a single-hole and a three-hole nozzle and conclude that both of these injector nozzles yield similar spray patterns and atomization and could be particularly useful for combustion systems where injection into a piston bowl is required.
12. Test aspect of single stage to orbit systems
NASA Astrophysics Data System (ADS)
Gaubatz, William A.; Nowlan, Daniel R.; Maras, Mathew G.; Copper, John A.; Coleman, Kate A.
1995-03-01
The McDonnell Douglas Delta Clipper Team recently completed the initial flight testing of a one third scale version of an operational single stage to orbit vehicle. The Delta Clipper Experimental, DC-X, is a 14 m tall, totally reusable, liquid hydrogen/liquid oxygen fueled test vehicle powered by four P&W RL-lOAS rocket engines. It has totally autonomous on board flight control and mission control systems; flight test mission requirements are simply added through software to the mission controller. The DC X is designed to explore and validate the low speed flight qualities of a vertical take-off and vertical landing spacecraft and its flight characteristics closely duplicate those predicted for the full scale DC-1 vehicle. The DC-1 vehicle would be capable of routinely flying people and/or cargo to and from space and would have a lift capacity for carrying 12 metric tons to low earth orbit.
13. Classification of Transient Phenomena in Distribution System using wavelet Transform
NASA Astrophysics Data System (ADS)
Sedighi, Alireza
2014-05-01
An efficient procedure for classification of transient phenomena in distribution systems is proposed in this paper. The proposed method has been applied to classify some transient phenomena such as inrush current, load switching, capacitor switching and single phase to ground fault. The new scheme is based on wavelet transform algorithm. All of the events for feature extraction and test are simulated using Electro Magnetic Transient Program (EMTP). Results show high accuracy of proposed method.
14. Coincident steam generator tube rupture and stuck-open safety relief valve carryover tests: MB-2 steam generator transient response test program
SciTech Connect
Garbett, K; Mendler, O J; Gardner, G C; Garnsey, R; Young, M Y
1987-03-01
In PWR steam generator tube rupture (SGTR) faults, a direct pathway for the release of radioactive fission products can exist if there is a coincident stuck-open safety relief valve (SORV) or if the safety relief valve is cycled. In addition to the release of fission products from the bulk steam generator water by moisture carryover, there exists the possibility that some primary coolant may be released without having first mixed with the bulk water - a process called primary coolant bypassing. The MB-2 Phase II test program was designed specifically to identify the processes for droplet carryover during SGTR faults and to provide data of sufficient accuracy for use in developing physical models and computer codes to describe activity release. The test program consisted of sixteen separate tests designed to cover a range of steady-state and transient fault conditions. These included a full SGTR/SORV transient simulation, two SGTR overfill tests, ten steady-state SGTR tests at water levels ranging from very low levels in the bundle up to those when the dryer was flooded, and three moisture carryover tests without SGTR. In these tests the influence of break location and the effect of bypassing the dryer were also studied. In a final test the behavior with respect to aerosol particles in a dry steam generator, appropriate to a severe accident fault, was investigated.
15. Measurement of transient acoustic fields using a single-shot pressure-sensitive paint system
NASA Astrophysics Data System (ADS)
Disotell, Kevin J.; Gregory, James W.
2011-07-01
A pressure-sensitive paint (PSP) system capable of measuring high-frequency acoustic fields with non-periodic, acoustic-level pressure changes is described. As an optical measurement technique, PSP provides the experimenter with a global distribution of pressure on a painted surface. To demonstrate frequency response and enhanced sensitivity to pressure changes, a PSP system consisting of a polymer/ceramic matrix binder with platinum tetra(pentafluorophenyl) porphyrin (PtTFPP) as the oxygen probe was applied to a wall inside an acoustic resonance cavity excited at 1.3 kHz. A data acquisition technique based on the luminescent decay lifetime of the oxygen sensors excited by a single pulse of light afforded the ability to capture instantaneous pressure fields with no phase-averaging. Superimposed wave-like structures were observed with a wavelength corresponding to a 4.7% difference from the theoretical value for a sound wave emanating from the speaker. High sound pressure cases upwards of 145 dB (re 20 ?Pa) exhibited skewed nodal lines attributed to a nonlinear acoustic field. The lowest sound pressure level of 125.4 dBcorresponding to an amplitude of 52.7 Pa, or approximately 0.05% of standard sea-level atmospheric pressureshowed that the paint could resolve the spatial details of the mode shape at the given resonance condition.
16. Reservoir engineering, transient pressure well testing, and petrophysical analyses of western gas sands. Annual report, July 1978-August 1979
SciTech Connect
Bixel, H.C.
1981-11-01
Improvement in gas deliverability by massive hydraulic fracturing of low permeability Western Gas Sands has been generally disappointing. This investigation uses petrophysical studies, transient pressure analysis of well performance, and parametric study of various fracture properties to aid in the understanding of the results of several DOE cost-shared MHF treatments. Both the transient pressure analysis and the parametric study utilize numerical simulation techniques. A generalized approach to pressure buildup analyses of tests with short flow periods is developed. The parametric analyses are focused on those variables of MHF treatments over which the operator and engineer have some control. Improvements in pressure measurement techniques are suggested as well as reasons why MHF treatments have had limited success.
17. Transient potentiation of spontaneous EPSPs in rat mossy cells induced by depolarization of a single neurone.
PubMed
Strowbridge, B W; Schwartzkroin, P A
1996-07-15
1. The amplitude and frequency of spontaneously occurring EPSPs recorded intracellularly in rat mossy cells was estimated by measuring membrane potential variance in short segments of a continuous voltage record. Changes in variance reflected changes in the amplitude and/or the frequency of spontaneous EPSPs. 2. Short trains of depolarizing current pulses evoked a delayed increase in membrane potential variance in 55% of trials. Variance increased by 487% during these responses and remained elevated for 124 +/- 16 s. Increases in variance were not associated with large changes in the intrinsic properties of the mossy cell such as resting membrane potential and input resistance. We termed this phenomenon depolarization-related potentiation (DRP). 3. Epochs of elevated variance were associated with an increase in both the average amplitude and frequency of spontaneous EPSPs. During the peak of the response, the mean interval between spontaneous EPSPs decreased by 36.8%. Computer-generated voltage records with randomly distributed EPSP amplitudes and inter-EPSP intervals suggested that this decrease in inter-EPSP intervals was not sufficient to account for the magnitude of the variance increase observed. Based on this model, we estimated that a 90% increase in the average amplitude of spontaneous EPSPs, in addition to the experimentally measured decrease in the average inter-EPSP interval, was required to reproduce the magnitude of the change in variance observed. In the potentiated state, the amplitude of spontaneous EPSPs often exceeded 10 mV. 4. We also observed epochs of increased variance that occurred spontaneously. These spontaneous epochs closely resembled epochs evoked by depolarizing stimuli, suggesting that the stimulus was acting as a trigger for a spontaneously occurring behaviour. Additional evidence supporting this hypothesis was provided by the observation that stereotyped patterns of increased variance could be evoked by brief stimuli, such as a single 5 s depolarizing step. Dual intracellular recordings from two mossy cells demonstrated that spontaneous epochs of increased variance occurred independently in different neurones. This result makes it unlikely that these variance increases were due to a global change in the slice environment such as a propagating wave of potassium ions. 5. Bath application of the Na+ channel blocker TTX eliminated most, but not all, of the normal on-going spontaneous EPSPs in mossy cells. Treatment with depolarizing current pulses was effective in potentiating TTX-resistant spontaneous EPSPs in three of seven trials. Potentiation also decreased the mean interval between TTX-resistant miniature EPSPs (by an average of 66.9%) in two trials examined. 6. These results suggest that DRP results from the activation of an intrinsic phenomenon within the dentate gyrus by strong depolarization of a single mossy cell. Our data suggest that several mechanisms are involved in the expression of DRP since changes in EPSP amplitude and frequency can occur with varying delays from the stimulus. The ability of depolarizing current pulses to potentiate TTX-resistant miniature EPSPs suggests that at least one component of this plasticity occurs at the granule cell-mossy cell synapse. PMID:8842007
18. Constitutive modeling of superalloy single crystals with verification testing
NASA Technical Reports Server (NTRS)
Jordan, Eric; Walker, Kevin P.
1985-01-01
The goal is the development of constitutive equations to describe the elevated temperature stress-strain behavior of single crystal turbine blade alloys. The program includes both the development of a suitable model and verification of the model through elevated temperature-torsion testing. A constitutive model is derived from postulated constitutive behavior on individual crystallographic slip systems. The behavior of the entire single crystal is then arrived at by summing up the slip on all the operative crystallographic slip systems. This type of formulation has a number of important advantages, including the prediction orientation dependence and the ability to directly represent the constitutive behavior in terms which metallurgists use in describing the micromechanisms. Here, the model is briefly described, followed by the experimental set-up and some experimental findings to date.
19. System level latchup mitigation for single event and transient radiation effects on electronics
DOEpatents
Kimbrough, Joseph Robert (Pleasanton, CA); Colella, Nicholas John (Livermore, CA)
1997-01-01
A "blink" technique, analogous to a person blinking at a flash of bright light, is provided for mitigating the effects of single event current latchup and prompt pulse destructive radiation on a micro-electronic circuit. The system includes event detection circuitry, power dump logic circuitry, and energy limiting measures with autonomous recovery. The event detection circuitry includes ionizing radiation pulse detection means for detecting a pulse of ionizing radiation and for providing at an output terminal thereof a detection signal indicative of the detection of a pulse of ionizing radiation. The current sensing circuitry is coupled to the power bus for determining an occurrence of excess current through the power bus caused by ionizing radiation or by ion-induced destructive latchup of a semiconductor device. The power dump circuitry includes power dump logic circuitry having a first input terminal connected to the output terminal of the ionizing radiation pulse detection circuitry and having a second input terminal connected to the output terminal of the current sensing circuitry. The power dump logic circuitry provides an output signal to the input terminal of the circuitry for opening the power bus and the circuitry for shorting the power bus to a ground potential to remove power from the power bus. The energy limiting circuitry with autonomous recovery includes circuitry for opening the power bus and circuitry for shorting the power bus to a ground potential. The circuitry for opening the power bus and circuitry for shorting the power bus to a ground potential includes a series FET and a shunt FET. The invention provides for self-contained sensing for latchup, first removal of power to protect latched components, and autonomous recovery to enable transparent operation of other system elements.
20. System level latchup mitigation for single event and transient radiation effects on electronics
DOEpatents
Kimbrough, J.R.; Colella, N.J.
1997-09-30
A blink technique, analogous to a person blinking at a flash of bright light, is provided for mitigating the effects of single event current latchup and prompt pulse destructive radiation on a micro-electronic circuit. The system includes event detection circuitry, power dump logic circuitry, and energy limiting measures with autonomous recovery. The event detection circuitry includes ionizing radiation pulse detection means for detecting a pulse of ionizing radiation and for providing at an output terminal thereof a detection signal indicative of the detection of a pulse of ionizing radiation. The current sensing circuitry is coupled to the power bus for determining an occurrence of excess current through the power bus caused by ionizing radiation or by ion-induced destructive latchup of a semiconductor device. The power dump circuitry includes power dump logic circuitry having a first input terminal connected to the output terminal of the ionizing radiation pulse detection circuitry and having a second input terminal connected to the output terminal of the current sensing circuitry. The power dump logic circuitry provides an output signal to the input terminal of the circuitry for opening the power bus and the circuitry for shorting the power bus to a ground potential to remove power from the power bus. The energy limiting circuitry with autonomous recovery includes circuitry for opening the power bus and circuitry for shorting the power bus to a ground potential. The circuitry for opening the power bus and circuitry for shorting the power bus to a ground potential includes a series FET and a shunt FET. The invention provides for self-contained sensing for latchup, first removal of power to protect latched components, and autonomous recovery to enable transparent operation of other system elements. 18 figs.
1. Novel board level drop test simulation using implicit transient analysis with input-G method
Jing-en Luan; Tong Yan Tee
2004-01-01
In recent several years, there are many efforts to study the reliability performance of IC package under drop impact loading by numerical modeling. Most of the models utilize LS-DYNA or ABAQUS types of explicit solvers. However, there is a lack of efficient implicit model for the organization without access to explicit solvers. This paper presents a novel non-linear transient dynamics
2. 49 CFR 232.309 - Equipment and devices used to perform single car air brake tests.
Code of Federal Regulations, 2013 CFR
2013-10-01
...Equipment and devices used to perform single car air brake tests. 232.309 Section...Equipment and devices used to perform single car air brake tests. (a) Equipment and devices used to perform single car air brake tests shall be tested for...
3. 49 CFR 232.309 - Equipment and devices used to perform single car air brake tests.
Code of Federal Regulations, 2010 CFR
2010-10-01
...Equipment and devices used to perform single car air brake tests. 232.309 Section...Equipment and devices used to perform single car air brake tests. (a) Equipment and devices used to perform single car air brake tests shall be tested for...
4. 49 CFR 232.309 - Equipment and devices used to perform single car air brake tests.
Code of Federal Regulations, 2011 CFR
2011-10-01
...Equipment and devices used to perform single car air brake tests. 232.309 Section...Equipment and devices used to perform single car air brake tests. (a) Equipment and devices used to perform single car air brake tests shall be tested for...
5. 49 CFR 232.309 - Equipment and devices used to perform single car air brake tests.
Code of Federal Regulations, 2012 CFR
2012-10-01
...Equipment and devices used to perform single car air brake tests. 232.309 Section...Equipment and devices used to perform single car air brake tests. (a) Equipment and devices used to perform single car air brake tests shall be tested for...
6. 49 CFR 232.309 - Equipment and devices used to perform single car air brake tests.
Code of Federal Regulations, 2014 CFR
2014-10-01
...Equipment and devices used to perform single car air brake tests. 232.309 Section...Equipment and devices used to perform single car air brake tests. (a) Equipment and devices used to perform single car air brake tests shall be tested for...
7. COMMIX-1C: A three-dimensional transient single-phase computer program for thermal-hydraulic analysis of single-component and multicomponent engineering systems
SciTech Connect
Domanus, H.M.; Cha, Y.S.; Chien, T.H.; Schmitt, R.C.; Sha, W.T. (Argonne National Lab., IL (USA))
1990-11-01
The COMMIX-1C computer program is an extended and improved version of previous COMMIX codes with four major additions or modifications: (1) a new finite-volume formulation for the mass, momentum, and energy equations to extend the applications to subsonic compressible flows and to make the calculations more robust; (2) a flow-modulated skew-upwind discretization scheme to reduce numerical diffusion; (3) two new matrix solvers for the discretized equations to increase the flexibility and efficiency of numerical computation; and (4) a k-{var epsilon} two-equation turbulence model that is more robust and better validated than those in previous COMMIX codes. In addition, there are numerous smaller modifications that improve overall operation greatly. COMMIX-1C solves the conservation equations of mass, momentum, and energy, as well as the transport equations of turbulence parameters. It is designed to perform steady- state/transient, single-phase, three-dimensional analysis of fluid flow with heat transfer in a single-component or a multicomponent engineering system. The program was developed for the analysis of heat transfer and fluid flow processes in a nuclear reactor system. However, it is designed in a generalized fashion so that, with little or no modification, it can be used to analyze processes in any engineering equipment or in any system. This document, Volume I (Equations and Numerics), describes in detail the basic equations, formulations, solution procedures, and models for auxiliary phenomena. Volume II (User's Guide and Manual) contains the input instruction, sample problems, flow charts, and description of available options and boundary conditions. 83 refs., 49 figs., 29 tabs.
8. Axisymmetric granular collapse: a transient 3D flow test of viscoplasticity.
PubMed
Lacaze, Laurent; Kerswell, Rich R
2009-03-13
A viscoplastic continuum theory has recently been proposed to model dense, cohesionless granular flows [P. Jop, Nature (London) 441, 727 (2006)10.1038/nature04801]. We confront this theory for the first time with a transient, three-dimensional flow situation--the simple collapse of a cylinder of granular matter onto a horizontal plane--by extracting stress and strain rate tensors directly from soft particle simulations. These simulations faithfully reproduce the different flow regimes and capture the observed scaling laws for the final deposit. Remarkably, the theoretical hypothesis that there is a simple stress-strain rate tensorial relationship does seem to hold across the whole flow even close to the rough boundary provided the flow is dense enough. These encouraging results suggest viscoplastic theory is more generally applicable to transient, multidirectional, dense flows and open the way for quantitative predictions in real applications. PMID:19392169
9. Testing of a low cooled ceramic nozzle vane under transient conditions
SciTech Connect
Dilzer, M.; Gutmann, C.; Schulz, A.; Wittig, S. [Univ. of Karlsruhe (Germany). Inst. fuer Thermische Stroemungsmaschinen
1999-04-01
At the Institut fuer Thermische Stroemungsmaschinen, University of Karlsruhe (ITS), a design technology has been introduced to reduce the mechanically and especially the thermally induced stresses in ceramic components. The concept is based on a three-layered construction (outer ceramic shell, heat insulating layer, and metallic core) and an optimization of the thicknesses of the single layers, in order to obtain a homogeneous temperature distribution in the ceramic structure. The optimization is performed by finite element analyses in combination with failure probability calculations. This methodology has been applied to increase the reliability of a first stage Sintered Silicon Carbide (SSiC) ceramic nozzle vane of a stationary gas turbine (70 MW/1400 C). As a result is was found that the mechanically and thermally induced loads have been reduced considerably and do not exceed 100 MPa, thus achieving adequate life based upon failure probability calculations. Even in a trip situation (fuel cutoff), when the highest loads do occur, the calculations demonstrate a significantly reduced failure probability. The results of the finite element analyses were verified by simulating the typical operating conditions after fuel cutoff in a test rig.
10. Single Stage Contactor Testing Of The Next Generation Solvent Blend
SciTech Connect
Herman, D. T.; Peters, T. B.; Duignan, M. R.; Williams, M. R.; Poirier, M. R.; Brass, E. A.; Garrison, A. G.; Ketusky, E. T.
2014-01-06
The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility at the Savannah River Site (SRS) is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent to increase the cesium decontamination factor. To support this integration of NGS into the MCU facility the Savannah River National Laboratory (SRNL) performed testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing utilized a blend of BOBCalixC6 based solvent and the NGS with the new extractant, MaxCalix, as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 liquid-to-liquid centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. The results indicate that hydraulically, the NGS solvent performed hydraulically similar to the current solvent which was expected. For the organic carryover 93% of the solvent is predicted to be recovered from the stripping operation and 96% from the extraction operation. As for the mass transfer, the NGS solvent significantly improved the cesium DF by at least an order of magnitude when extrapolating the One-stage results to actual Seven-stage extraction operation with a stage efficiency of 95%.
11. Single Component Sorption-Desorption Test Experimental Design Approach Discussions
SciTech Connect
Phil WInston
2011-09-01
A task was identified within the fission-product-transport work package to develop a path forward for doing testing to determine behavior of volatile fission products behavior and to engage members of the NGNP community to advise and dissent on the approach. The following document is a summary of the discussions and the specific approaches suggested for components of the testing. Included in the summary isare the minutes of the conference call that was held with INL and external interested parties to elicit comments on the approaches brought forward by the INL participants. The conclusion was that an initial non-radioactive, single component test will be useful to establish the limits of currently available chemical detection methods, and to evaluated source-dispersion uniformity. In parallel, development of a real-time low-concentration monitoring method is believed to be useful in detecting rapid dispersion as well as desorption phenomena. Ultimately, the test cycle is expected to progress to the use of radio-traced species, simply because this method will allow the lowest possible detection limits. The consensus of the conference call was that there is no need for an in-core test because the duct and heat exchanger surfaces that will be the sorption target will be outside the main neutron flux and will not be affected by irradiation. Participants in the discussion and contributors to the INL approach were Jeffrey Berg, Pattrick Calderoni, Gary Groenewold, Paul Humrickhouse, Brad Merrill, and Phil Winston. Participants from outside the INL included David Hanson of General Atomics, Todd Allen, Tyler Gerczak, and Izabela Szlufarska of the University of Wisconsin, Gary Was, of the University of Michigan, Sudarshan Loyalka and Tushar Ghosh of the University of Missouri, and Robert Morris of Oak Ridge National Laboratory.
12. Test of Single-Stage Axial-Flow Fan
NASA Technical Reports Server (NTRS)
Bell, E Barton
1942-01-01
A single-stage axial fan was built and tested in the shop of the propeller-research tunnel of the NACA. The fan comprised a simple 24-blade rotor having a diameter of 21 inches and a solidity of 0.86 and a set of 37 contravanes having a solidity of 1.33. The rotor was driven by a 25-horsepower motor capable of rotating at a speed of 3600 r.p.m. The fan was tested for volume, pressure, and efficiency over a range of delivery pressures and volumes for a wide range of contravane and blade-angle settings. The test results are presented in chart form in terms of nondimensional units in order that similar fans may be accurately designed with a minimum effort. The maximum efficiency (88 percent) was obtained by the fan at a blade angle of 30 degrees and a contravane angle of 70 degrees. An efficiency of 80 percent was obtained by the fan with the contravanes removed.
13. Free drop test simulation for portable IC package by implicit transient dynamics FEM
Scott Irving; Yong Liu
2004-01-01
Free drop test performance of portable IC packages is a key reliability criteria for handheld products. Various experimental test methods are widely applied to measure the drop test response and to test for visual and electrical failures after the drop test. However, the experimental data we can collect is very limited, especially for the impact of stress wave propagation and
14. Impact of IL28B-Related Single Nucleotide Polymorphisms on Liver Transient Elastography in Chronic Hepatitis C Infection
PubMed Central
Ydreborg, Magdalena; Westin, Johan; Rembeck, Karolina; Lindh, Magnus; Norrgren, Hans; Holmberg, Anna; Wejstl, Rune; Norkrans, Gunnar; Cardell, Kristina
2013-01-01
Background and Aims Recently, several genome-wide association studies have revealed that single nucleotide polymorphisms (SNPs) in proximity to IL28B predict spontaneous clearance of hepatitis C virus (HCV) infection as well as outcome following pegylated interferon and ribavirin therapy among genotype 1 infected patients. Additionally the presence of the otherwise favorable IL28B genetic variants in the context of HCV genotype 3 infection reportedly entail more pronounced liver fibrosis and steatosis. The present study aimed to evaluate the impact of IL28B SNP variability on liver stiffness as accessed by transient elastography. Methods Seven hundred and seventy-one Swedish HCV infected patients sequentially undergoing liver stiffness measurement by means of Fibroscan in the context of a real-life trial had samples available for IL28B genotyping (rs12979860) and HCV genotyping. Results CCrs12979860 was more common among HCV genotype 2 or 3 infected treatment-nave patients than among those infected with genotype 1 (P<0.0001). Additionally CCrs12979860 among HCV genotype 3 infected patients was associated with higher liver stiffness values (P?=?0.004), and higher AST to platelet ratio index (APRI; p?=?0.02) as compared to carriers of the T allele. Among HCV genotype 1 infected patients, CCrs12979860 was significantly associated with higher viral load (P?=?0.001), with a similar non-significant trend noted among HCV genotype 3 infected patients. Conclusion This study confirms previous reports that the CCrs12979860 SNP is associated with more pronounced liver pathology in patients chronically infected with HCV genotype 3 as compared to genotype 1, suggesting that IL28B genetic variants differently regulates the course of HCV infection across HCV genotypes. PMID:24244641
15. 49 CFR 232.307 - Modification of the single car air brake test procedures.
Code of Federal Regulations, 2012 CFR
2012-10-01
...2012-10-01 false Modification of the single car air brake test procedures. 232...Requirements 232.307 Modification of the single car air brake test procedures. (a...railroad industry may seek modification of the single car air brake test procedures...
16. 49 CFR 232.307 - Modification of the single car air brake test procedures.
Code of Federal Regulations, 2013 CFR
2013-10-01
...2013-10-01 false Modification of the single car air brake test procedures. 232...Requirements 232.307 Modification of the single car air brake test procedures. (a...railroad industry may seek modification of the single car air brake test procedures...
17. 49 CFR 232.307 - Modification of the single car air brake test procedures.
Code of Federal Regulations, 2010 CFR
2010-10-01
...2010-10-01 false Modification of the single car air brake test procedures. 232...Requirements 232.307 Modification of the single car air brake test procedures. (a...railroad industry may seek modification of the single car air brake test procedures...
18. 49 CFR 232.307 - Modification of the single car air brake test procedures.
Code of Federal Regulations, 2011 CFR
2011-10-01
...2011-10-01 false Modification of the single car air brake test procedures. 232...Requirements 232.307 Modification of the single car air brake test procedures. (a...railroad industry may seek modification of the single car air brake test procedures...
19. 49 CFR 232.307 - Modification of the single car air brake test procedures.
Code of Federal Regulations, 2014 CFR
2014-10-01
...2014-10-01 false Modification of the single car air brake test procedures. 232...Requirements 232.307 Modification of the single car air brake test procedures. (a...railroad industry may seek modification of the single car air brake test procedures...
20. Transient Plume Model Testing Using LADEE Spacecraft Attitude Control System Operations
NASA Technical Reports Server (NTRS)
Woronowicz, Michael
2011-01-01
We have learned it is conceivable that the Neutral Mass Spectrometer on board the Lunarr Atmosphere Dust Environment Explorer (LADEE) could measure gases from surface-reflected Attitude Control System (ACS) thruster plume. At minimum altitude, the measurement would be maximized, and gravitational influence minimized ("short" time-of-flight (TOF) situation) Could use to verify aspects of thruster plume modeling Model the transient disturbance to NMS measurements due to ACS gases reflected from lunar surface Observe evolution of various model characteristics as measured by NMS Species magnitudes, TOF measurements, angular distribution, species separation effects
1. Single tube support post thermal analysis and test results
SciTech Connect
Nicol, T.H.; Boroski, W.N.; Schoo, C.J.
1993-05-01
Cold mass structural supports used in prototype Superconducting Super Collider (SSC) 50 mm dipole magnets built at Fermilab and Brookhaven are adaptations of the design developed during the 40 mm design program at Fermilab. The design essentially consists of two composite tubes nested within each other as a means of maximizing the thermal path length. In addition it provides an ideal way to utilize materials best suited for the temperature range over which they must operate. Filament wound S-glass is used between 300K and 80K. Filament wound graphite fiber is used between 80K and 20K and between 20K and 4.5K. An alternate design for supports which uses a single composite tube has been developed at Fermilab and continues to be refined by the industrial contractors. The advantage of the new design is cost reduction due to a significantly simpler assembly and incorporation of many common parts. This report describes the thermal analysis and testing of a single composite tube support post whose function is identical to that of the current reentrant design.
2. Testing the single degenerate channel for supernova Ia
NASA Astrophysics Data System (ADS)
Parsons, Steven
2014-10-01
The progenitors of supernova Ia are close binaries containing white dwarfs. Of crucial importance to the evolution of these systems is how much material the white dwarf can stably accrete and hence grow in mass. This occurs during a short-lived intense phase of mass transfer known as the super soft source (SSS) phase. The short duration of this phase and large extinction to soft X-rays means that only a handful are known in our Galaxy. Far more can be learned from the underlying SSS progenitor population of close white dwarf plus FGK type binaries. Unfortunately, these systems are hard to find since the main-sequence stars completely outshine the white dwarfs at optical wavelengths. Because of this, there are currently no known close white dwarf binaries with F, G or early K type companions, making it impossible to determine the contribution of the single degenerate channel towards supernova Ia. Using the GALEX and RAVE surveys we have now identified the first large sample of FGK stars with UV excesses, a fraction of which are these illusive, close systems. Following an intense ground based spectroscopic investigation of these systems, we have identified 5 definite close binaries, with periods of less than a few days. Here we apply for COS spectroscopic observations to measure the mass and temperature of the white dwarfs in order to determine the future evolution of these systems. This will provide a crucial test for the single degenerate channel towards supernova Ia.
3. Transient thermal analysis of PWRs by a single-pass procedure using a simplified nodal layout
E-print Network
Liu, Jack S. H.
1979-01-01
PWR accident conditions and analysis methods have been reviewed. Limitations of the simplified method with respect to analysis of these accident conditions are drawn and two transients ( loss of coolant flow, seized rotor) ...
4. Radiation tests for a single-GEM-loaded gaseous detector
NASA Astrophysics Data System (ADS)
Lee, Kyong Sei; Hong, Byungsik; Park, Sung Keun; Kim, Sang Yeol
2014-11-01
We report on a systematic study of a single-gas-electron-multiplier (GEM)-loaded gaseous detector developed for precision measurements of high-energy particle beams and for dose verification in particle therapy. In the present study, a 256-channel prototype detector having an active area of 16 16 cm2 and operating using a continuous current-integration-mode signal-processing method was manufactured and tested with X-rays emitted from a 70-kV X-ray generator and 43-MeV protons provided by the MC50 proton cyclotron at the Korea Institute of Radiological and Medical Science (KIRAMS). The amplified detector response was measured for X-rays with an intensity of about 5 106 Hz cm-2. The linearity of the detector response to the particle flux was examined and validated by using 43-MeV proton beams. The non-uniform development of the amplification for the gas electrons in space was corrected by applying a proper calibration to the channel responses of the measured beam-profile data. We conclude from the radiation tests that the detector developed in the present study will allow us to perform quality measurements of various high-energy particle beams and to apply the technology to dose-verification measurements in particle therapy.
5. Development of the IM147: an alternative inspection/maintenance mass-emission transient test to address vehicle preconditioning concerns.
PubMed
Joy, Richard W; Heirigs, Philip L; Torgerson, Garrett D; St Denis, Michael; Austin, Thomas C; Gordon, Jay; Tefft, Bob; Lindner, Jim
2004-03-01
A series of studies was performed to develop an alternative to the U.S. Environmental Protection Agency's gold standard IM240 mass-based emission test. The new IM147 test was based on the second phase of the IM240 that consists of 147 sec of transient vehicle operation. Paired IM240/IM147 tests were conducted on vehicles ranging from 1981 to 1996 to determine IM147 cutpoints and excess emissions were identified. Additionally, an optimized test procedure was developed that combined possible triplicate IM147s with improved drive trace quality control, fast-pass, and retest methods. The optimized procedure was found to provide improved vehicle preconditioning with a relatively minor decrease in excess emissions identification. Resulting identification rates ranged from 96 to 100% for hydrocarbons (HC), 93-100% for CO, and 93-100% for NOx, depending on cutpoint selection, while false failures caused by lack of vehicle preconditioning were reduced to essentially zero. Significant vehicle throughput improvements were achieved through the development of software algorithms involving modal fast-pass and retest procedures. Modal drive trace variation limits also were developed to improve test accuracy. The combination of the algorithms reduced average IM147 test times by nearly 60%. PMID:15061610
6. Implementation and testing of the first prompt search for gravitational wave transients with electromagnetic counterparts
E-print Network
2012-01-12
Aims. A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. A first program initiating EM follow-ups to possible transient GW events has been developed and exercised by the LIGO and Virgo community in association with several partners. In this paper, we describe and evaluate the methods used to promptly identify and localize GW event candidates and to request images of targeted sky locations. Methods. During two observing periods (Dec 17 2009 to Jan 8 2010 and Sep 2 to Oct 20 2010), a low-latency analysis pipeline was used to identify GW event candidates and to reconstruct maps of possible sky locations. A catalog of nearby galaxies and Milky Way globular clusters was used to select the most promising sky positions to be imaged, and this directional information was delivered to EM observatories with time lags of about thirty minutes. A Monte Carlo simulation has been used to evaluate the low-latency GW pipeline's ability to reconstruct source positions correctly. Results. For signals near the detection threshold, our low-latency algorithms often localized simulated GW burst signals to tens of square degrees, while neutron star/neutron star inspirals and neutron star/black hole inspirals were localized to a few hundred square degrees. Localization precision improves for moderately stronger signals. The correct sky location of signals well above threshold and originating from nearby galaxies may be observed with ~50% or better probability with a few pointings of wide-field telescopes.
7. Implementation and Testing of the First Prompt Search for Gravitational Wave Transients with Electromagnetic Counterparts
NASA Technical Reports Server (NTRS)
Abadie, J.; Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Affeldt, C.; Agathos, M.; Ajith, P.; Allen, B.; Allen, G. S.; Ceron, E. Amador; Amariutei, D.; Amin, R. S.; Anderson, S. B.; Anderson, W. G.; Araya, M. C.; Aston, S. M.; Astone, P.; Atkinson, D.; Aufmuth, P.; Blackburn, L.
2012-01-01
Aims. A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. A first program initiating EM follow-ups to possible transient GW events has been developed and exercised by the LIGO and Virgo community in association with several partners. In this paper, we describe and evaluate the methods used to promptly identify and localize GW event candidates and to request images of targeted sky locations. Methods. During two observing periods (Dec. 17, 2009 to Jan. 8, 2010 and Sep. 2 to Oct. 20, 2010), a low-latency analysis pipeline was used to identify GW event candidates and to reconstruct maps of possible sky locations. A catalog of nearby galaxies and MilkyWay globular clusters was used to select the most promising sky positions to be imaged, and this directional information was delivered to EM observatories with time lags of about thirty minutes. A Monte Carlo simulation has been used to evaluate the low-latency GW pipeline's ability to reconstruct source positions correctly. Results. For signals near the detection threshold, our low-latency algorithms often localized simulated GW burst signals to tens of square degrees, while neutron star/neutron star inspirals and neutron star/black hole inspirals were localized to a few hundred square degrees. Localization precision improves for moderately stronger signals. The correct sky location of signals well above threshold and originating from nearby galaxies may be observed with 50% or better probability with a few pointings of wide-field telescopes.
8. Summary of air permeability data from single-hole injection tests in unsaturated fractured tuffs at the Apache Leap Research Site: Results of steady-state test interpretation
SciTech Connect
Guzman, A.G.; Geddis, A.M.; Henrich, M.J.; Lohrstorfer, C.F.; Neuman, S.P. [Univ. of Arizona, Tucson, AZ (United States). Dept. of Hydrology and Water Resources
1996-03-01
This document summarizes air permeability estimates obtained from single hole pneumatic injection tests in unsaturated fractured tuffs at the Covered Borehole Site (CBS) within the larger apache Leap Research Site (ALRS). Only permeability estimates obtained from a steady state interpretation of relatively stable pressure and flow rate data are included. Tests were conducted in five boreholes inclined at 45{degree} to the horizontal, and one vertical borehole. Over 180 borehole segments were tested by setting the packers 1 m apart. Additional tests were conducted in segments of lengths 0.5, 2.0, and 3.0 m in one borehole, and 2.0 m in another borehole, bringing the total number of tests to over 270. Tests were conducted by maintaining a constant injection rate until air pressure became relatively stable and remained so for some time. The injection rate was then incremented by a constant value and the procedure repeated. The air injection rate, pressure, temperature, and relative humidity were recorded. For each relatively stable period of injection rate and pressure, air permeability was estimated by treating the rock around each test interval as a uniform, isotropic porous medium within which air flows as a single phase under steady state, in a pressure field exhibiting prolate spheroidal symmetry. For each permeability estimate the authors list the corresponding injection rate, pressure, temperature and relative humidity. They also present selected graphs which show how the latter quantities vary with time; logarithmic plots of pressure versus time which demonstrate the importance of borehole storage effects during the early transient portion of each incremental test period; and semilogarithmic plots of pressure versus recovery time at the end of each test sequence.
9. A REVIEW OF SINGLE SPECIES TOXICITY TESTS: ARE THE TESTS RELIABLE PREDICTORS OF AQUATIC ECOSYSTEM COMMUNITY RESPONSES?
EPA Science Inventory
This document provides a comprehensive review to evaluate the reliability of indicator species toxicity test results in predicting aquatic ecosystem impacts, also called the ecological relevance of laboratory single species toxicity tests....
10. M3B2 and M5B3 Formation in Diffusion-Affected Zone During Transient Liquid Phase Bonding Single-Crystal Superalloys
NASA Astrophysics Data System (ADS)
Sheng, Naicheng; Hu, Xiaobing; Liu, Jide; Jin, Tao; Sun, Xiaofeng; Hu, Zhuangqi
2015-04-01
Precipitates in the diffusion-affected zone (DAZ) during transient liquid phase bonding (TLP) single-crystal superalloys were observed and investigated. Small size and dendritic-shaped precipitates were identified to be M3B2 borides and intergrowth of M3B2/M5B3 borides. The orientation relationships among M3B2, M5B3, and matrix were determined using transmission electron microscope (TEM). Composition characteristics of these borides were also analyzed by TEM energy-dispersive spectrometer. Because this precipitating phenomenon deviates from the traditional parabolic transient liquid phase bonding model which assumed a precipitates free DAZ during TLP bonding, some correlations between the deviation of the isothermal solidification kinetics and these newly observed precipitating behaviors were discussed and rationalized when bonding the interlayer containing the high diffusivity melting point depressant elements and substrates of low solubility.
11. Equivalence of robust delay-fault and single stuck-fault test generation
Alexander Saldanha; Robert K. Brayton; Alberto L. Sangiovanni-Vincentelli
1992-01-01
A link between the problems of robust delay-fault and single stuck-fault test generation is established. In particular, it is proved that all the robust test vector pairs for any path delay-fault in a network are directly obtained by all the test vectors for a corresponding single stuck-fault in a modified network. Since single stuck-fault test generation is a well solved
12. FLASH analysis of the MB-2 steady state, operational transient and stability tests
SciTech Connect
Coffield, R.D.; Lincoln, F.W.; Johnson, E.G.
1993-11-01
This report describes testing performed in the Model Boiler No. 2 (MB-2) facility located at the Westinghouse Engineering Test Facility in Tampa, Florida which provided valuable data for validating steam generator computer code analytical models. MB-2 is scaled to represent a vertical tube Model F steam generator which is used in many commercial PWR plants. A major consideration in the MB-2 test rig design was to make it as prototypical as possible to the Model F commercial PWR steam generator.
13. Test of the fluctuation theorem for single-electron transport
NASA Astrophysics Data System (ADS)
Kng, B.; Rssler, C.; Beck, M.; Marthaler, M.; Golubev, D. S.; Utsumi, Y.; Ihn, T.; Ensslin, K.
2013-04-01
Using time-resolved charge detection in a double quantum dot, we present an experimental test of the fluctuation theorem. The fluctuation theorem, a result from nonequilibrium statistical mechanics, quantifies the ratio of occurrence of fluctuations that drive a small system against the direction favored by the second law of thermodynamics. Here, these fluctuations take the form of single electrons flowing against the source-drain bias voltage across the double quantum dot. Our results, covering configurations close to as well as far from equilibrium, agree with the theoretical predictions, when the finite bandwidth of the charge detection is taken into account. In further measurements, we study a fluctuation relation that is a generalization of the Johnson-Nyquist formula and relates the second-order conductance to the voltage dependence of the noise. Current and noise can be determined with the time-resolved charge detection method. Our measurements confirm the fluctuation relation in the nonlinear transport regime of the double quantum dot.
14. Testing of the single-element stretched-membrane dish
NASA Astrophysics Data System (ADS)
Grossman, J. W.; Houser, R. M.; Erdman, W. W.
1992-02-01
The goal of the Stretched-Membrane Dish Program is the development of a dish solar concentrator fabricated with a single optical element capable of collecting 60 kWt. Solar Kinetics, Inc., has constructed a prototype 7-meter dish to demonstrate the manufacturability and optical performance of this innovative design. The reflective surface of the dish consists of a plastically deformed metal membrane with a separate reflective polymer membrane on top, both held in place by a low-level vacuum. Sandia conducted a test program to determine the on-sum performance of the dish. The vacuum setting was varied 8.9- to 17. 2-cm of water column and the vertex to target distance was varied over a range of 15.24 cm to evaluate beam quality. The optimal setting for the vacuum was 11.4 centimeters of water column with the best beam quality of 6.4 centimeters behind the theoretical focal point of the dish. Flux arrays based on slope error from the CIRCE2 computer code were compared to the measured flux array of the dish. The uniformly distributed slope error of 2.3 milliradians was determined as the value that would produce a modeled array with the minimum mean square difference to the measured array. Cold water calorimetry measured a power of 23.3 (plus minus) .3 kWt. Reflectivity changed from an initial value of 88.3 percent to 76.7 percent over a one year period.
15. Phase V of the single-breath washout test
NASA Technical Reports Server (NTRS)
Nichol, G. M.; Michels, D. B.; Guy, H. J. B.
1982-01-01
A downward-deflecting phase V is often seen following the terminal rise (phase IV) in single-breath washout tests. To investigate the nature of phase V, experiments using simultaneous washouts of N2 and tracer boluses of Ar were performed on eight normal nonsmoking subjects aged 27-41 who exhibited a phase V. Phase V is found to occur in all subjects at expiratory flow rates between 0.1 and 2.0 l/sec shortly after expiration became flow limited. Volumes of both phases IV and V increase with increasing flow rate. The difference between the exhaled volumes at which flow became limited and phase V appeared is shown to be approximately equal to the anatomic dead space. Results support a model of lung emptying in a gravitational field in which flow limitation occurs first in the lower lung regions and then progresses toward the upper regions, causing phase IV. A decrease in the amount of flow from the upper relative to the lower regions after all regions have become flow limited then causes phase V.
16. Radiation Tests for a Single-GEM Loaded Gaseous Detector
E-print Network
Lee, Kyong Sei; Kim, Sang Yeol; Park, Sung Keun
2014-01-01
We report on the systematic study of a single-gas-electron-multiplication (GEM) loaded gaseous detector developed for precision measurements of high-energy particle beams and dose-verification measurements. In the present study, a 256-channel prototype detector with an active area of 16$\\times$16 cm$^{2}$, operated in a continuous current-integration-mode signal-processing method, was manufactured and tested with x rays emitted from a 70-kV x-ray generator and 43-MeV protons provided by the MC50 proton cyclotron at the Korea Institute of Radiological and Medical Science (KIRAMS). The amplified detector response was measured for the x rays with an intensity of about 5$\\times$10$^{6}$ Hz cm$^{-2}$. The linearity of the detector response to the particle flux was examined and validated by using 43-MeV proton beams. The non-uniform development of the amplification for the gas electrons in space was corrected by applying proper calibration to the channel responses of the measured beam-profile data. We concluded fro...
17. Variable Depth Bragg Peak Method for Single Event Effects Testing
NASA Technical Reports Server (NTRS)
Buchner, S.; Kanyogoro, N.; Foster, C.; O'Neill, P.
2011-01-01
18. Differentiation of Performance-Limiting Voltage Transients during Nb3Sn Magnet Testing
NASA Astrophysics Data System (ADS)
Lietzke, A. F.; Mattafirri, S.; McInturff, A. D.; Nyman, M.; Dietderich, D. R.; Gourlay, S. A.; Sabbi, G. L.
2006-03-01
The Superconducting Magnet Group at Lawrence Berkeley National Laboratory has been developing high-field, brittle-superconductor, accelerator magnet technology for several years. While recent dramatic increases in Nb3Sn superconducting current density, (Jc = 3000 A/mm2 at 12 Tesla, 4.2 K) have facilitated the achievement of record peak dipole bore-fields (16 Tesla), the number and size of fast intra-coil flux-adjustments of the "flux-jump" variety have increased with the current density. In 2000, with state-of-the art (Jc = 2000 A/mm2 at 12 T) Nb3Sn conductor, the associated coil voltage transients were observed to be large enough to cause nuisance "quench-detector" magnet-protection false-alarms. Subsequent Jc increases have resulted in large enough flux-jumps to cause premature quenches in some magnets, at currents well below those predicted by their virgin strand superconducting "short-sample" measurements. This paper will examine various types of quench-onsets and their distinguishing characteristics. The associated observational techniques are briefly discussed.
19. Results of the latest transient well pressure tests at Cerro Prieto
SciTech Connect
Abril G, A.; Vargas G, C.
1981-01-01
The equipment used in the interference and two-rate flow tests carried out at the Cerro Prieto geothermal field during 1980 are described. The results of two interference tests are presented, one between wells M-110 and M-104, and the other between wells M-7 and Q-757. The data was interpreted using type curve matching analysis. Results of two-rate flow tests carried out in wells M-102 and M-7 are also discussed. A technique for making two-rate flow tests is proposed. This approach, which attempts to avoid the uncertainty of present flow-rate measurements, makes use of devices for direct measurements of separated water and steam. Conclusions based on the above interpretations and recommendations for future tests are presented.
20. Phase 3 integrated water recovery testing at MSFC: Single loop test results and lessons learned
NASA Technical Reports Server (NTRS)
Carter, Donald Layne; Bagdigian, Robert M.
1993-01-01
A series of tests has been conducted at the NASA Marshall Space Flight Center (MSFC) to evaluate the performance of the Space Station Freedom (SSF) water recovery system. Potable and urine reclamation processors were integrated with waste water generation equipment and sucessfully operated for a total of 144 days. This testing marked the first occasion in which the waste feed sources for the previous potable and hygiene loops were combined into a single loop and processed to potable water quality. Reclaimed potable water from the combined waste waters routinely met the SSF water quality specifications.In the last stage of testing, data was obtained that indicated that the water processor (WP) presterilizer may not be required to meet the potable water quality specification. The removal of the presterilizer from the Water Processor design would provide a significant power savings, though an increase in the residence time of the catalytic oxidation reactor may be required to meet the potable microbial and total Organic Carbon specifications. This paper summarizes the test objectives, system design, test activities/protocols, significant results/anomalies and major lessons learned.
1. Assembly of GABA, Receptor Subunits: Analysis of Transient Single-Cell Expression Utilizing a Fluorescent Substrate\\/Marker Gene Technique
Timothy P. Angelotti; Michael D. Uhler; Robert L. Macdonald
1993-01-01
GABA, receptor channels (GABARs) composed of varying combinations of (Y,, @,, and yZS subunits were transiently expressed in mammalian cell lines. The whole-cell patch- clamp recording technique was used to determine which combinations of GABAR subunits produced functional re- ceptor channels and whether assembly of GABAR subunits into receptor channels followed a random or preferred se- quence. To identify rapidly
2. Design and operation of a rapid thermal transient component testing sodium loop
SciTech Connect
Crandall, D.L.
1984-04-16
A specific problem developed during the design of an on-line sampling system for the Sodium Loop Safety Facility fast breeder reactor experiments. Rapid fluctuations in the sodium temperature, caused by reactor operation and shutdown, exposed the system components to conditions that could result in fatigue failure. A component test loop was designed and built at the Idaho National Engineering Laboratory to allow experimental qualification of component integrity. This paper outlines test system requirements, describes the design and special features, presents test procedures ad relates significant operating experience.
3. Testing of the EURATOM LCT coil in the toroidal arrangement of the International Fusion Superconducting Magnet Test Facility without external pulsed fields (standard-1) and with them (standard II) and an extended single-coil test
SciTech Connect
Friesinger, G.; Gauss, S.; Komarek, P.; Lubell, M.S.; McManamy, T.J.; Maurer, W.; Shen, S.S.; Siewerdt, L.; Ulbricht, A.; Wuchner, F.
1988-03-01
Testing of the European LCT coil, a forced-flow NbTi coil, with the five other coils in the International Fusion Superconducting Magnet Test Facility (IFSMTF) has been in progress since the beginning of 1986. By the end of July 1987, the Euratom-LCT coil had passed a single-coil test, a test in toroidal configuration with and without poloidal field transients, and an extended single-coil test up to its design limits. In this test, the coil reached, in stable operation, a field of 9 T at 140% of rated current. It reached the short-sample values of the strands used in the cable. The coil was operated up to 8 T with and without poloidal field transients in a toroidal configuration. The mass flow rate was reduced by a factor of 5 compared with the design value without any visible impact on stability. Averaged ac losses (winding, 14 W; case, 7 W) were measured under LCT specified poloidal field pulses, and the findings agreed with those of the short-sample measurements. The mechanical properties behaved as predicted by calculations. No global movement of the winding in the coil case was found, although the coil has already experienced 50% (14MN) of the maximum out-of-plane force. The operating limits were determined by measuring the current-sharing temperature. It was found that the helium mass flow rate had an impact on the hot-spot temperature of a normal region. All results obtained demonstrate that the applied technology has achieved reliable engineering standards.
4. Geological Hypothesis Testing and Investigations of Coupling with Transient Electromagnetics (TEM)
NASA Astrophysics Data System (ADS)
Adams, A. C.; Moeller, M. M.; Snyder, E.; Workman, E. J.; Urquhart, S.; Bedrosian, P.; Pellerin, L.
2014-12-01
Transient electromagnetic (TEM) data were acquired in Borrego Canyon within the Santo Domingo Basin of the Rio Grande Rift, central New Mexico, during the 2014 Summer of Applied Geophysical Experience (SAGE) field program. TEM surveys were carried out in several regions both to investigate geologic structure and to illustrate the effects of coupling to anthropogenic structures. To determine an optimal survey configuration, 50, 100 and 200 m square transmitter loops were deployed; estimates of depth-of-investigation and logistical considerations determined that 50 m loops were sufficient for production-style measurements. A resistive (100s of ohm-m) layer was identified at a depth of 25-75 m at several locations, and interpreted as dismembered parts of one or more concealed volcanic flows, an interpretation consistent with Tertiary volcanic flows that cap the Santa Anna Mesa immediately to the south. TEM soundings were also made across an inferred fault to investigate whether fault offset is accompanied by lateral changes in electrical resistivity. Soundings within several hundred meters of the inferred fault strand were identical, indicating no resistivity contrast across the fault, and possibly an absence of recent activity. An old windmill and water tank, long-abandoned, offered an excellent laboratory to study the effect of coupling to metallic anthropogenic structures. The character of the measured data strongly suggests the water tank is in electrical contact with the earth (galvanic coupling), and an induced response was persistent to more than 1 second after current turn-off. Coupling effects could be identified at least 150 meters from the tank. Understanding the mechanism behind such coupling and the ability to identify coupled data are critical skills, as one-dimensional modeling of data is affected by such coupling producing artificial conductive layers at depth.
5. Methodological factors involved in neonatal screening using transient-evoked otoacoustic emissions and automated auditory brainstem response testing.
PubMed
Thornton, A Roger D; Kimm, Lindsay; Kennedy, Colin R
2003-08-01
The methodological factors involved in screening neonates for hearing loss, using transient-evoked otoacoustic emissions (TEOAEs) and automated auditory brainstem responses, have been evaluated from a large sample of neonates. The risk factors, commonly used to select babies for a targeted screen, have very little correlation with failing TEOAE testing. The parameters used to determine passing or failing the TEOAE test and the false alarm rate change markedly with age in the first few days of life as, of course, did the percentage of babies who failed the test. The stimulus level used was the default setting for the Otodynamics equipment but the stimulus level measured in the ear canal decreased over the first 140 h of life. It is thought that this reflects the impedance changes in outer and middle ears and possible changes in middle ear dynamics. The methodological variables investigated here can illuminate some of the differences in previous reports of neonatal screening, in particular the reported hit and false alarm rates. PMID:12948603
6. Electro-optic modulator based gate transient suppression for sine-wave gated InGaAs/InP single photon avalanche photodiode
NASA Astrophysics Data System (ADS)
Zhang, Yixin; Zhang, Xuping; Shi, Yuanlei; Ying, Zhoufeng; Wang, Shun
2014-06-01
Capacitive gate transient noise has been problematic for the high-speed single photon avalanche photodiode (SPAD), especially when the operating frequency extends to the gigahertz level. We proposed an electro-optic modulator based gate transient noise suppression method for sine-wave gated InGaAs/InP SPAD. With the modulator, gate transient is up-converted to its higher-order harmonics that can be easily removed by low pass filtering. The proposed method enables online tuning of the operating rate without modification of the hardware setup. At 250 K, detection efficiency of 14.7% was obtained with 4.810-6 per gate dark count and 3.6% after-pulse probabilities for 1550-nm optical signal under 1-GHz gating frequency. Experimental results have shown that the performance of the detector can be maintained within a designated frequency range from 0.97 to 1.03 GHz, which is quite suitable for practical high-speed SPAD applications operated around the gigahertz level.
7. Delayed emission of surface-generated trapped carriers in transient charge transport of single-crystal and polycrystalline HgI2
NASA Astrophysics Data System (ADS)
Zuck, Asaf; Schieber, Michael M.; Khakhan, Oleg; Burshtein, Zeev
2003-01-01
Transient charge transport (TCT) measurements were used to evaluate the electrical conduction properties of HgI2 single crystals. Some comparative preliminary results for polycrystalline mercuric iodide (poly-HgI2) thick-film X-ray detectors are also reported. The latter were prepared by physical vapor deposition (PVD). The mobility , trapping time 2, and surface recombination velocity s of electrons or holes were determined by analyses of transient voltages developed across the sample in response to a drift of the corresponding charge carriers created by alpha particle absorption near one of the electrodes. Electron-, and hole mobilities of single crystal HgI2 were n = 80 cm2/Vs and p = 4.8 cm2/Vs, respectively. Trapping times were 2n ? 22 V and 2p ? 8 V, and surface recombination velocities sn ? 1.1 105 cm/s and sp ? 3.6 103 cm/s . Those of the polycrystalline material depend on the deposition technology, and vary between 65 and 88 cm2/Vs for electrons, and between 4.3 and 4.1 cm2/Vs for holes. Bulk trapping-times and surface recombination velocities appear of the same order of magnitude as in the single crystal. An effect of carriers being first generated in near-surface traps and then gradually released is observed for both the single crystal and the polycrystalline material. It is stronger for electrons as compared to holes, and stronger in the polycrystalline material as compared to the single crystal.
8. Transient Lift-off Test Results for an Experimental Hybrid Bearing in Air
E-print Network
Klooster, David
2011-02-22
the hydrodynamic pressure, resulting from the relative motion of two surfaces, overcomes the forces acting on the rotor; no indication of hydrodynamic lift-off is provided. Hydrostatic lift-off results from the external supply pressure (which for this test rig...
9. Solution-processed single-walled carbon nanotube field effect transistors and bootstrapped inverters for disintegratable, transient electronics
E-print Network
Rogers, John A.
Solution-processed single-walled carbon nanotube field effect transistors and bootstrapped field effect transistors based on single-walled carbon nanotube network and formed on a gold transistors with singlewalledcarbon nanotube network on flexible substrate J. Appl. Phys. 114, 214504 (2013
10. Numerical and field tests of hydraulic transients at Piva power plant
NASA Astrophysics Data System (ADS)
Giljen, Z.
2014-03-01
In 2009, a sophisticated field investigation was undertaken and later, in 2011, numerical tests were completed, on all three turbine units at the Piva hydroelectric power plant. These tests were made in order to assist in making decisions about the necessary scope of the reconstruction and modernisation of the Piva hydroelectric power plant, a plant originally constructed in the mid-1970s. More specifically, the investigation included several hydraulic conditions including both the start-up and stopping of each unit, load rejection under governor control from different initial powers, as well as emergency shut-down. Numerical results were obtained using the method of characteristics in a representation that included the full flow system and the characteristics of each associated Francis turbine. The impact of load rejection and emergency shut-down on the penstock pressure and turbine speed changes are reported and numerical and experimental results are compared, showing close agreement.
11. Qualification test procedures and results for Honeywell solar collector subsystem, single-family residence
NASA Technical Reports Server (NTRS)
1977-01-01
The test procedures and results in qualifying the Honeywell single family residence solar collector subsystem are presented. Testing was done in the following areas: pressure, service loads, hail, solar degradation, pollutants, thermal degradation, and outgassing.
12. The diagnostic odds ratio: a single indicator of test performance
Afina S. Glas; Jeroen G. Lijmer; Martin H. Prins; Gouke J. Bonsel; Patrick M. M. Bossuyt
2003-01-01
Diagnostic testing can be used to discriminate subjects with a target disorder from subjects without it. Several indicators of diagnostic performance have been proposed, such as sensitivity and specificity. Using paired indicators can be a disadvantage in comparing the performance of competing tests, especially if one test does not outperform the other on both indicators. Here we propose the use
13. Estimation of the Doppler Coefficient from a Lower Power Transient Observed in a Zero-Power Reactor Physics Test of a PWR (I)Methodology
Masashi TSUJI; Yoichiro SHIMAZU; Tadashi NARABAYASHI; Yasunori OHOKA; Masatoshi YAMASAKI; Yasushi HANAYAMA
2009-01-01
A method for estimating the Doppler coefficient from low power transient data that are measured in a routine experiment conducted in a zero-power reactor physics test of a PWR power plant has been developed. A dynamics identification model was introduced by considering two dynamics components for reactor kinetics and heat removal in the primary coolant loops. The dynamics identification method
14. Saliva testing after single and chronic administration of dihydrocodeine
G. Skopp; L. Ptsch; K. Klinder; B. Richter; R. Aderjan; R. Mattern
2001-01-01
In the present study, concentrations of dihydrocodeine and its metabolites in saliva and serum were compared after single\\u000a low-dose and chronic high-dosage administration of the drug. In the first investigation, blood and saliva were collected periodically\\u000a from six subjects after oral administration of 60 mg dihydrocodeine. In the second study, 20 subjects on oral dihydrocodeine\\u000a maintenance provided single samples of
15. Mechanical testing of large thallium doped sodium iodide single crystals
NASA Technical Reports Server (NTRS)
Lee, H. M.
1985-01-01
The findings of mechanical tests performed on five thallium-doped sodium iodide NaI(Tl) crystals are presented. These crystals are all in the shape of circular flat plates, 20.0 in. in diameter an d0.5 in. thick. The test setup, testing procedure, and the test data are presented. Large crystals exhibit a high degree of material plasticity, as well as a much higher strength than previously anticipated, on the order of 500 psi. Also revealed from the testing is the fact that crystal with a large number of grain boundaries developed less plasticity, and therefore less permanent deformation, than those with fewer grain boundaries.
16. Single-cell-derived mesenchymal stem cells overexpressing Csx/Nkx2.5 and GATA4 undergo the stochastic cardiomyogenic fate and behave like transient amplifying cells
SciTech Connect
Yamada, Yoji [BioFrontier Laboratories, Kyowa Hakko Kogyo Co. Ltd., 3-6-6 Asahi-machi, Machida-shi, Tokyo 194-8533 (Japan); Sakurada, Kazuhiro [BioFrontier Laboratories, Kyowa Hakko Kogyo Co. Ltd., 3-6-6 Asahi-machi, Machida-shi, Tokyo 194-8533 (Japan); Takeda, Yukiji [National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535 (Japan); Gojo, Satoshi [National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535 (Japan); Umezawa, Akihiro [National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535 (Japan)]. E-mail: [email protected]
2007-02-15
Bone marrow-derived stromal cells can give rise to cardiomyocytes as well as adipocytes, osteocytes, and chondrocytes in vitro. The existence of mesenchymal stem cells has been proposed, but it remains unclear if a single-cell-derived stem cell stochastically commits toward a cardiac lineage. By single-cell marking, we performed a follow-up study of individual cells during the differentiation of 9-15c mesenchymal stromal cells derived from bone marrow cells. Three types of cells, i.e., cardiac myoblasts, cardiac progenitors and multipotent stem cells were differentiated from a single cell, implying that cardiomyocytes are generated stochastically from a single-cell-derived stem cell. We also demonstrated that overexpression of Csx/Nkx2.5 and GATA4, precardiac mesodermal transcription factors, enhanced cardiomyogenic differentiation of 9-15c cells, and the frequency of cardiomyogenic differentiation was increased by co-culturing with fetal cardiomyocytes. Single-cell-derived mesenchymal stem cells overexpressing Csx/Nkx2.5 and GATA4 behaved like cardiac transient amplifying cells, and still retained their plasticity in vivo.
17. Results of the ETV-1 breadboard tests under steady-state and transient conditions. [conducted in the NASA-LeRC Road Load Simulator
NASA Technical Reports Server (NTRS)
Sargent, N. B.; Dustin, M. O.
1981-01-01
Steady state tests were run to characterize the system and component efficiencies over the complete speed-torque capabilities of the propulsion system in both motoring and regenerative modes of operation. The steady state data were obtained using a battery simulator to separate the effects on efficiency caused by changing battery state-of-charge and component temperature. Transient tests were performed to determine the energy profiles of the propulsion system operating over the SAE J227a driving schedules.
18. Soumis J Eur. Ceram. Soc. Intermediate temperature SOFC single cell test
E-print Network
Boyer, Edmond
1 Soumis J Eur. Ceram. Soc. Intermediate temperature SOFC single cell test using Nd1.95NiO4 Abstract This work deals with SOFC single cell tests using neodymium nickelate Nd1.95NiO4+ as cathode electrochemical activity with respect to classical materials. The SOFC cells were fabricated from an anode
19. 76 FR 34801 - Petition for Modification of Single Car Air Brake Test Procedures
Federal Register 2010, 2011, 2012, 2013, 2014
2011-06-14
...FRA-2010-0174] Petition for Modification of Single Car Air Brake Test Procedures In accordance...FRA) grant a modification of the single car air brake test procedures as prescribed...FRA-2010-0174. PATH operates a fleet of 25 flat cars in consist with revenue cars utilized...
20. Stress Transfer in Single Fiber\\/ Resin Tensile Tests
W. D. Bascom; R. M. Jensen
1986-01-01
Microscale (25 mm gauge length) dogbone resin specimens with single carbon fibers embedded through the length of the specimen have been studied as a method for determining the fiber-resin interphase strength. The specimens are pulled in tension until the fiber fragments to a critical length, lc. Evidence is presented here, based primarily on the relaxation of stress birefringence around the
1. Transient drawdown solution for a constant pumping test in finite two-zone confined aquifers
NASA Astrophysics Data System (ADS)
Wang, C.-T.; Yeh, H.-D.; Tsai, C.-S.
2012-02-01
The drawdown solution has been widely used to analyze pumping test data for the determination of aquifer parameters when coupled with an optimization scheme. The solution can also be used to predict the drawdown due to pumping and design the dewatering system. The drawdown solution for flow toward a finite-radius well with a skin zone in a confined aquifer of infinite extent in radial direction had been developed before. To our best knowledge, the drawdown solution in confined aquifers of finite extent with a skin zone so far has never before been presented in the groundwater literature. This article presents a mathematical model for describing the drawdown distribution due to a constant-flux pumping from a finite-radius well with a skin zone in confined aquifers of finite extent. The analytical solution of the model is developed by applying the methods of Laplace transforms, Bromwich contour integral, and residue theorem. This solution can be used to investigate the effects of finite boundary and conductivity ratio on the drawdown distribution. In addition, the inverse relationship between Laplace- and time-domain variables is used to develop the large time solution which can reduce to the Thiem solution if there is no skin zone.
2. Transient drawdown solution for a constant pumping test in finite two-zone confined aquifers
NASA Astrophysics Data System (ADS)
Wang, C.-T.; Yeh, H.-D.; Tsai, C.-S.
2011-10-01
The drawdown solution has been widely used to analyze pumping test data for the determination of aquifer parameters when coupled with an optimization scheme. The solution can also be used to predict the drawdown due to pumping and design the dewatering system. The drawdown solution for flow toward a finite-radius well with a skin zone in a confined aquifer of infinite extent in radial direction had been developed before. To our best knowledge, the drawdown solution in confined aquifers of finite extent so far has never before been presented in the groundwater literature. This article presents a mathematical model for describing the drawdown distribution due to a constant-flux pumping from a finite-radius well with a skin zone in confined aquifers of finite extent. The analytical solution of the model is developed by applying the methods of Laplace transforms and Bromwich contour integral. This solution can be used to investigate the effects of finite boundary and conductivity ratio on the drawdown distribution. In addition, the inverse relationship between Laplace- and time-domain variables is used to develop the large time solution which can reduce to the Thiem solution if there is no skin zone.
3. Test procedures and instructions for single shell tank saltcake cesium removal with crystalline silicotitanate
SciTech Connect
Duncan, J.B.
1997-01-07
This document provides specific test procedures and instructions to implement the test plan for the preparation and conduct of a cesium removal test, using Hanford Single Shell Tank Saltcake from tanks 24 t -BY- I 10, 24 1 -U- 108, 24 1 -U- 109, 24 1 -A- I 0 1, and 24 t - S-102, in a bench-scale column. The cesium sorbent to be tested is crystalline siticotitanate. The test plan for which this provides instructions is WHC-SD-RE-TP-024, Hanford Single Shell Tank Saltcake Cesium Removal Test Plan.
4. Info-gap robustness for the correlation of tests and simulations of a non-linear transient
NASA Astrophysics Data System (ADS)
Hemez, Franois M.; Ben-Haim, Yakov
2004-11-01
An alternative to the theory of probability is applied to the problem of assessing the robustness, to uncertainty in model parameters, of the correlation between measurements and computer simulations. The analysis is based on the theory of information-gap uncertainty, which models the clustering of uncertain events in families of nested sets instead of assuming a probability structure. The system investigated is the propagation of a transient impact through a layer of hyper-elastic material. The two sources of non-linearity are (1) the softening of the constitutive law representing the hyper-elastic material and (2) the contact dynamics at the interface between metallic and crushable materials. The robustness of the correlation between test and simulation, to sources of parameter variability, is first studied to identify the parameters of the model that significantly influence the agreement between measurements and predictions. Model updating under non-probabilistic uncertainty is then illustrated, based on two complementary immunity functions: the robustness to uncertainty and the opportunity from uncertainty. Finally an info-gap model is embedded within a probability density function to represent uncertainty in the knowledge of the model's parameters and their correlation structure. Although computationally expensive, it is demonstrated that info-gap reasoning can greatly enhance our understanding of a moderately complex system when the theory of probability cannot be applied due to insufficient information.
5. Tests of Lorentz symmetry in single beta decay
E-print Network
Jorge S. Diaz
2014-08-25
Low-energy experiments studying single beta decay can serve as sensitive probes of Lorentz invariance that can complement interferometric searches for deviations from this spacetime symmetry. Experimental signatures of a dimension-three operator for Lorentz violation that are unobservable in neutrino oscillations are described for the decay the polarized and unpolarized neutrons as well as for measurements of the spectral endpoint in beta decay.
6. [Acute stent thrombosis and reverse transient left ventricular dilatation after performing a single-photon emission computed tomography myocardial perfusion].
PubMed
Miranda, B; Pizzi, M N; Aguad-Bruix, S; Domingo, E; Candell-Riera, J
2015-01-01
A 63-year-old male patient with a history of stent implantation in the left anterior descending three months before. Due to the presentation of vegetative symptoms, he was referred for gated-SPECT myocardial perfusion. During acquisition of the resting images he presented chest pain and ST segment elevation, so that urgent cardiac catheterization was performed, showing stent thrombosis. Rest perfusion imaging showed a defect in anterior and apical perfusion, more severe and extensive than in the stress images, with striking left ventricular dilatation and a fall in the ejection fraction related to the acute ischemia phenomenon. Intense exercise is associated with a transient activation of the coagulation system and hemodynamic changes that might induce thrombosis, especially in recently implanted coronary stents that probably still have not become completely endothelialized. PMID:25129322
7. Single-Tube Ultrasonic Testing of Pile Integrity 1
Joram M. Amir
It is now universally acknowledged that in bored piles (drilled shafts, caissons) flaws can, and therefore will, occur. The majority of the important flaws can be detected by standard non-destructive testing methods. There are situations, however, when none of these methods is viable. One example is that of small diameter piles, penetrating through rockfill with large cavities and then socketed
8. Neutronics, steady-state, and transient analyses for the Poland MARIA reactor for irradiation testing of LEU lead test fuel assemblies from CERCA : ANL independent verification results.
SciTech Connect
Garner, P. L.; Hanan, N. A. (Nuclear Engineering Division)
2011-06-07
The MARIA reactor at the Institute of Atomic Energy (IAE) in Swierk (30 km SE of Warsaw) in the Republic of Poland is considering conversion from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel assemblies (FA). The FA design in MARIA is rather unique; a suitable LEU FA has never been designed or tested. IAE has contracted with CERCA (the fuel supply portion of AREVA in France) to supply 2 lead test assemblies (LTA). The LTAs will be irradiated in MARIA to burnup level of at least 40% for both LTAs and to 60% for one LTA. IAE may decide to purchase additional LEU FAs for a full core conversion after the test irradiation. The Reactor Safety Committee within IAE and the National Atomic Energy Agency in Poland (PAA) must approve the LTA irradiation process. The approval will be based, in part, on IAE submitting revisions to portions of the Safety Analysis Report (SAR) which are affected by the insertion of the LTAs. (A similar process will be required for the full core conversion to LEU fuel.) The analysis required was established during working meetings between Argonne National Laboratory (ANL) and IAE staff during August 2006, subsequent email correspondence, and subsequent staff visits. The analysis needs to consider the current high-enriched uranium (HEU) core and 4 core configurations containing 1 and 2 LEU LTAs in various core positions. Calculations have been performed at ANL in support of the LTA irradiation. These calculations are summarized in this report and include criticality, burn-up, neutronics parameters, steady-state thermal hydraulics, and postulated transients. These calculations have been performed at the request of the IAE staff, who are performing similar calculations to be used in their SAR amendment submittal to the PAA. The ANL analysis has been performed independently from that being performed by IAE and should only be used as one step in the verification process.
9. Psychometric Characteristics of Single-Word Tests of Children's Speech Sound Production
ERIC Educational Resources Information Center
Flipsen, Peter, Jr.; Ogiela, Diane A.
2015-01-01
Purpose: Our understanding of test construction has improved since the now-classic review by McCauley and Swisher (1984) . The current review article examines the psychometric characteristics of current single-word tests of speech sound production in an attempt to determine whether our tests have improved since then. It also provides a resource
10. Identification of Anisotropic Yield Criterion Parameters from a Single Biaxial Tensile Test
E-print Network
Boyer, Edmond
Identification of Anisotropic Yield Criterion Parameters from a Single Biaxial Tensile Test ZHANG biaxial tensile test. It is shown, from finite element simulations, that the strain distribution biaxial tensile test. Introduction Sheet metals usually exhibit a plastic anisotropy due to previous
11. Determination of carbon fiber adhesion to thermoplastic polymers using the single fiber/matrix tensile test
NASA Technical Reports Server (NTRS)
Bascom, W. D.; Cordner, L. W.; Hinkley, J. L.; Johnston, N. J.
1986-01-01
The single fiber adhesion shear test has been adapted to testing the adhesion between carbon fiber and thermoplastic polymers. Tests of three thermoplastics, polycarbonate, polyphenylene oxide and polyetherimide indicate the shear adhesion strength is significantly less than of an epoxy polymer to the same carbon fiber.
12. Single-molecule spectroscopy and femtosecond transient absorption studies on the excitation energy transfer process in ApcE(1-240) dimers.
PubMed
Long, Saran; Zhou, Meng; Tang, Kun; Zeng, Xiao-Li; Niu, Yingli; Guo, Qianjin; Zhao, Kai-Hong; Xia, Andong
2015-05-13
ApcE(1-240) dimers with one intrinsic phycocyanobilin (PCB) chromophore in each monomer that is truncated from the core-membrane linker (ApcE) of phycobilisomes (PBS) in Nostoc sp. PCC 7120 show a sharp and significantly red-shifted absorption. Two explanations either conformation-dependent Frster resonance energy transfer (FRET) or the strong exciton coupling limit have been proposed for red-shifted absorption. This is a classic example of the special pair in the photosynthetic light harvesting proteins, but the mechanism of this interaction is still a matter of intense debate. We report the studies using single-molecule and transient absorption spectra on the interaction in the special pair of ApcE dimers. Our results demonstrate the presence of conformation-dependent FRET between the two PCB chromophores in ApcE dimers. The broad distributions of fluorescence intensities, lifetimes and polarization difference from single-molecule measurements reveal the heterogeneity of local protein-pigment environments in ApcE dimers, where the same molecular structures but different protein environments are the main reason for the two PCB chromophores with different spectral properties. The excitation energy transfer rate between the donor and the acceptor about (110 ps)(-1) is determined from transient absorption measurements. The red-shifted absorption in ApcE dimers could result from more extending conformation, which shows another type of absorption redshift that does not depend on strong exciton coupling. The results here stress the importance of conformation-controlled spectral properties of the chemically identical chromophores, which could be a general feature to control energy/electron transfer, widely existing in the light harvesting complexes. PMID:25925197
13. Advanced development of the spectrum sciences Model 5005-TF, single-event test fixture
SciTech Connect
Ackermann, M.R.; Browning, J.S. (Sandia National Labs., Albuquerque, NM (USA)); Hughlock, B.W. (Boeing Aerospace and Electronics Co., Seattle, WA (USA)); Lum, G.K. (Lockheed Missiles and Space Co., Sunnyvale, CA (USA)); Tsacoyeanes, W.C. (Draper (Charles Stark) Lab., Inc., Cambridge, MA (USA)); Weeks, M.D. (Spectrum Sciences, Inc., Santa Clara, CA (USA))
1990-09-01
This report summarizes the advanced development of the Spectrum Sciences Model 5005-TF, Single-Event Test Fixture. The Model 5005-TF uses a Californium-252 (Cf-252) fission-fragment source to test integrated circuits and other devices for the effects of single-event phenomena. Particle identification methods commonly used in high-energy physics research and nuclear engineering have been incorporated into the Model 5005-TF for estimating the particle charge, mass, and energy parameters. All single-event phenomena observed in a device under test (DUT) are correlated with an identified fission fragment, and its linear energy transfer (LET) and range in the semiconductor material of the DUT.
14. RELAP5\\/MOD3 Analysis of Transient Steam-Generator Behavior During Turbine Trip Test of a Prototype Fast Breeder Reactor MONJU
Yoshihisa Shindo; Hiroshi Endo; Tomoko Ishizu; Kazuo Haga
2006-01-01
In order to develop a thermal-hydraulic model of the steam-generator (SG) to simulate transient phenomena in the sodium cooled fast breeder reactor (FBR) MONJU, Japan Nuclear Energy Safety Organization (JNES) verified the SG model using the RELAP5\\/MOD3 code against the results of the turbine trip test at a 40% power load of MONJU. The modeling by using RELAP5 was considered
15. Design and testing of a high accuracy robotic single-cell manipulator
E-print Network
Yoon, Jun Young, S.M. Massachusetts Institute of Technology
2011-01-01
We have designed, built and tested a high accuracy robotic single-cell manipulator to be able to pick individual cells from array of microwells, each 30 Pm or 50 pm cubed. Design efforts have been made for higher accuracy, ...
16. Compendium of Test Results of Single Event Effects Conducted by the Jet Propulsion Laboratory
Gregory R. Allen
2008-01-01
This paper reports heavy ion and proton induced single event effects results for a variety of microelectronic devices targeted for possible use in NASA spacecrafts. The compendium covers a sampling of devices tested over the past eight years.
17. Compendium of Recent Test Results of Single Event Effects Conducted by the Jet Propulsion Laboratory
NASA Technical Reports Server (NTRS)
Allen, Gregory R.; Guertin, Steven M.; Scheick, Leif Z.; Irom, Farokh; Zajac, Stephanie
2012-01-01
This paper reports heavy ion, proton, and laser induced single event effects results for a variety of microelectronic devices targeted for possible use in NASA spacecrafts. The compendium covers devices tested within the years of 2010 through 2012.
18. Research on reliability enhancement testing for single-phase smart meter
Sitong Wang; Ranran Luo; Hui Zhou; Jie Su; Xiaolei Zhu
2011-01-01
Single-phase smart meter as a key part of State Grid, the reliability of it has already become a problem not allow of being neglected. In this paper, a reliability enhancement testing method on single-phase smart meters is developed. The main sensitive stress and the weak parts which influence the reliability of single-phase smart meter have been discussed based on the
19. Haplotypes vs single marker linkage disequilibrium tests: what do we gain?
Joshua Akey; Li Jin; Momiao Xiong
2001-01-01
The genetic dissection of complex diseases represents a formidable challenge for modern human genetics. Recently, it has been suggested that linkage disequilibrium (LD) based methods will be a powerful approach for delineating complex disease genes. Most proposed LD test statistics search for association between a single marker and a putative trait locus. However, the power of a single marker association
20. Parametric Testing of Chevrons on Single Flow Hot Jets
NASA Technical Reports Server (NTRS)
Bridges, James; Brown, Clifford A.
2004-01-01
A parametric family of chevron nozzles have been studied, looking for relationships between chevron geometric parameters, flow characteristics, and far-field noise. Both cold and hot conditions have been run at acoustic Mach number 0.9. Ten models have been tested, varying chevron count, penetration, length, and chevron symmetry. Four comparative studies were defined from these datasets which show: that chevron length is not a major impact on either flow or sound; that chevron penetration increases noise at high frequency and lowers it at low frequency, especially for low chevron counts; that chevron count is a strong player with good low frequency reductions being achieved with high chevron count without strong high frequency penalty; and that chevron asymmetry slightly reduces the impact of the chevron. Finally, it is shown that although the hot jets differ systematically from the cold one, the overall trends with chevron parameters is the same.
1. First high power pulsed tests of a dressed 325 MHz superconducting single spoke resonator at Fermilab
SciTech Connect
Madrak, R.; Branlard, J.; Chase, B.; Darve, C.; Joireman, P.; Khabiboulline, T.; Mukherjee, A.; Nicol, T.; Peoples-Evans, E.; Peterson, D.; Pischalnikov, Y.; /Fermilab
2011-03-01
In the recently commissioned superconducting RF cavity test facility at Fermilab (SCTF), a 325 MHz, {beta} = 0.22 superconducting single-spoke resonator (SSR1) has been tested for the first time with its input power coupler. Previously, this cavity had been tested CW with a low power, high Q{sub ext} test coupler; first as a bare cavity in the Fermilab Vertical Test Stand and then fully dressed in the SCTF. For the tests described here, the design input coupler with Q{sub ext} {approx} 10{sup 6} was used. Pulsed power was provided by a Toshiba E3740A 2.5 MW klystron.
2. The Development and Validation of a Formula for Measuring Single-Sentence Test Item Readability.
ERIC Educational Resources Information Center
Homan, Susan; And Others
1994-01-01
A study was conducted with 782 elementary school students to determine whether the Homan-Hewitt Readability Formula could identify the readability of a single-sentence test item. Results indicate that a relationship exists between students' reading grade levels and responses to test items written at higher readability levels. (SLD)
3. Analytical solutions for efficient interpretation of single-well push-pull tracer tests
EPA Science Inventory
Single-well push-pull tracer tests have been used to characterize the extent, fate, and transport of subsurface contamination. Analytical solutions provide one alternative for interpreting test results. In this work, an exact analytical solution to two-dimensional equations descr...
4. Is Single Stool Occult Blood Test or Serum CEA Level Valuable in Health Check Up?
Ming-Chang Li; Jen-Kou Lin; Tzu-Chen Lin; Wei-Shone Chen; Jeng-Kae Jiang; Shung-Haur Yang; Huann-Sheng Wang; Shih-Ching Chang
2006-01-01
Purpose. Stool occult blood tests and serum CEA level examinations are widely used at health check-up of detecting colorectal lesions. The aim of this study is to evaluate the effectiveness of using single stool occult blood tests or serum CEA levels in routine health check up. Methods. We examined 1404 patients who came for health check up at Veterans General
5. COMMIX-1AR/P: A three-dimensional transient single-phase computer program for thermal hydraulic analysis of single and multicomponent systems. Volume 2, Users guide
SciTech Connect
Garner, P.L.; Blomquist, R.N.; Gelbard, E.M.
1992-09-01
The COMMIX-1AR/P computer program is designed for analyzing the steady-state and transient aspects of single-phase fluid flow and heat transfer in three spatial dimensions. This version is an extension of the modeling in COMMIX-1A to include multiple fluids in physically separate regions of the computational domain, modeling descriptions for pumps, radiation heat transfer between surfaces of the solids which are embedded in or surround the fluid, a k-{var_epsilon} model for fluid turbulence, and improved numerical techniques. The porous-medium formulation in COMMIX allows the program to be applied to a wide range of problems involving both simple and complex geometrical arrangements. The input preparation and execution procedures are presented for the COMMIX-1AR/P program and several postprocessor programs which produce graphical displays of the calculated results.
6. COMMIX-1AR/P: A three-dimensional transient single-phase computer program for thermal hydraulic analysis of single and multicomponent systems. Volume 3, Programmers guide
SciTech Connect
Garner, P.L.; Blomquist, R.N.; Gelbard, E.M.
1992-09-01
The COMMIX-LAR/P computer program is designed for analyzing the steady-state and transient aspects of single-phase fluid flow and heat transfer in three spatial dimensions. This version is an extension of the modeling in COMMIX-lA to include multiple fluids in physically separate regions of the computational domain, modeling descriptions for pumps, radiation heat transfer between surfaces of the solids which are embedded in or surround the fluid, a keg model for fluid turbulence, and improved numerical techniques. The porous-medium formulation in COMMIX allows the program to be applied to a wide range of problems involving both simple and complex geometrical arrangements. The internal aspects of the COMMIX-LAR/P program are presented, covering descriptions of subprograms, variables, and files.
7. A Nuclear Interaction Model for Understanding Results of Single Event Testing with High Energy Protons
NASA Technical Reports Server (NTRS)
Culpepper, William X.; ONeill, Pat; Nicholson, Leonard L.
2000-01-01
An internuclear cascade and evaporation model has been adapted to estimate the LET spectrum generated during testing with 200 MeV protons. The model-generated heavy ion LET spectrum is compared to the heavy ion LET spectrum seen on orbit. This comparison is the basis for predicting single event failure rates from heavy ions using results from a single proton test. Of equal importance, this spectra comparison also establishes an estimate of the risk of encountering a failure mode on orbit that was not detected during proton testing. Verification of the general results of the model is presented based on experiments, individual part test results, and flight data. Acceptance of this model and its estimate of remaining risk opens the hardware verification philosophy to the consideration of radiation testing with high energy protons at the board and box level instead of the more standard method of individual part testing with low energy heavy ions.
8. Characterization of single crystal mechanical test specimens for advanced turbine applications
SciTech Connect
Lipetzky, Kirsten G.; Green, Robert E. Jr. [Center for Nondestructive Evaluation, Johns Hopkins University, Baltimore, Maryland 21218 (United States)
1999-12-02
A series of fifteen mechanical test specimens made from a nickel-based superalloy were supplied by Siemens Westinghouse in order that Asymmetric Crystal Topography (ACT), an x-ray diffraction technique, be used to confirm which samples were single crystal samples and which samples contained low angle grain boundaries. It had been determined (by another investigator) prior to the manufacture of the mechanical test specimens, which 'raw' material contained low angle grain boundaries and which material was single crystalline in nature. Siemens Westinghouse requisitioned the production of mechanical test specimens from several manufacturers, with specific requirements that some of the samples were to be single crystalline and that other samples were to contain low angle grain boundaries within the gauge length. Once completed, Siemens Westinghouse wanted to confirm that the samples were properly manufactured and selected a representative portion of the mechanical test samples to be examined via ACT.
9. Analytical solutions for efficient interpretation of single-well push-pull tracer tests
Junqi Huang; John A. Christ; Mark N. Goltz
2010-01-01
Single-well push-pull tracer tests have been used to characterize the extent, fate, and transport of subsurface contamination. Analytical solutions provide one alternative for interpreting test results. In this work, an exact analytical solution to two-dimensional equations describing the governing processes acting on a dissolved compound during a modified push-pull test (advection, longitudinal and transverse dispersion, first-order decay, and rate-limited sorption\\/partitioning
10. TUCOP failure threshold test CO6R
G. E. Culley; P. C. Ferrell; R. Herbert; W. J. Woods
1984-01-01
The C06R test was the sixth single-pin test in the collaborative US\\/UK PFR\\/TREAT transient testing program. It was designed to study the mechanism, time and location of cladding failure and first fuel escape in an intermediate channel transient undercooling - overpower accident (TUCOP). It complements the LO5 and LO7 tests which studied post failure fuel dispersal in a similar hypothetical
11. Non-invasive prenatal testing for single gene disorders: exploring the ethics.
PubMed
Deans, Zuzana; Hill, Melissa; Chitty, Lyn S; Lewis, Celine
2013-07-01
Non-invasive prenatal testing for single gene disorders is now clearly on the horizon. This new technology offers obvious clinical benefits such as safe testing early in pregnancy. Before widespread implementation, it is important to consider the possible ethical implications. Four hypothetical scenarios are presented that highlight how ethical ideals of respect for autonomy, privacy and fairness may come into play when offering non-invasive prenatal testing for single gene disorders. The first scenario illustrates the moral case for using these tests for 'information only', identifying a potential conflict between larger numbers of women seeking the benefits of the test and the wider social impact of funding tests that do not offer immediate clinical benefit. The second scenario shows how the simplicity and safety of non-invasive prenatal testing could lead to more autonomous decision-making and, conversely, how this could also lead to increased pressure on women to take up testing. In the third scenario we show how, unless strong safeguards are put in place, offering non-invasive prenatal testing could be subject to routinisation with informed consent undermined and that woman who are newly diagnosed as carriers may be particularly vulnerable. The final scenario introduces the possibility of a conflict of the moral rights of a woman and her partner through testing for single gene disorders. This analysis informs our understanding of the potential impacts of non-invasive prenatal testing for single gene disorders on clinical practice and has implications for future policy and guidelines for prenatal care. PMID:23188047
12. Non-invasive prenatal testing for single gene disorders: exploring the ethics
PubMed Central
Deans, Zuzana; Hill, Melissa; Chitty, Lyn S; Lewis, Celine
2013-01-01
Non-invasive prenatal testing for single gene disorders is now clearly on the horizon. This new technology offers obvious clinical benefits such as safe testing early in pregnancy. Before widespread implementation, it is important to consider the possible ethical implications. Four hypothetical scenarios are presented that highlight how ethical ideals of respect for autonomy, privacy and fairness may come into play when offering non-invasive prenatal testing for single gene disorders. The first scenario illustrates the moral case for using these tests for information only', identifying a potential conflict between larger numbers of women seeking the benefits of the test and the wider social impact of funding tests that do not offer immediate clinical benefit. The second scenario shows how the simplicity and safety of non-invasive prenatal testing could lead to more autonomous decision-making and, conversely, how this could also lead to increased pressure on women to take up testing. In the third scenario we show how, unless strong safeguards are put in place, offering non-invasive prenatal testing could be subject to routinisation with informed consent undermined and that woman who are newly diagnosed as carriers may be particularly vulnerable. The final scenario introduces the possibility of a conflict of the moral rights of a woman and her partner through testing for single gene disorders. This analysis informs our understanding of the potential impacts of non-invasive prenatal testing for single gene disorders on clinical practice and has implications for future policy and guidelines for prenatal care. PMID:23188047
13. Switching transients in a superconducting coil
SciTech Connect
Owen, E.W.; Shimer, D.W.
1983-11-18
A study is made of the transients caused by the fast dump of large superconducting coils. Theoretical analysis, computer simulation, and actual measurements are used. Theoretical analysis can only be applied to the simplest of models. In the computer simulations two models are used, one in which the coil is divided into ten segments and another in which a single coil is employed. The circuit breaker that interrupts the current to the power supply, causing a fast dump, is represented by a time and current dependent conductance. Actual measurements are limited to measurements made incidental to performance tests on the MFTF Yin-yang coils. It is found that the breaker opening time is the critical factor in determining the size and shape of the transient. Instantaneous opening of the breaker causes a lightly damped transient with large amplitude voltages to ground. Increasing the opening time causes the transient to become a monopulse of decreasing amplitude. The voltages at the external terminals are determined by the parameters of the external circuit. For fast opening times the frequency depends on the dump resistor inductance, the circuit capacitance, and the amplitude on the coil current. For slower openings the dump resistor inductance and the current determine the amplitude of the voltage to ground at the terminals. Voltages to ground are less in the interior of the coil, where transients related to the parameters of the coil itself are observed.
14. HEDL experimental transient overpower program
T. Hikido; G. E. Culley
1976-01-01
HEDL is conducting a series of experiments to evaluate the performance of Fast Flux Test Facility (FFTF) prototypic fuel pins up to the point of cladding breach. A primary objective of the program is to demonstrate the adequacy of fuel pin and Plant Protective System (PPS) designs for terminated transients. Transient tests of prototypic FFTF fuel pins previously irradiated in
15. Comparative Performance of Four Single Extreme Outlier Discordancy Tests from Monte Carlo Simulations
PubMed Central
Daz-Gonzlez, Lorena; Quiroz-Ruiz, Alfredo
2014-01-01
Using highly precise and accurate Monte Carlo simulations of 20,000,000 replications and 102 independent simulation experiments with extremely low simulation errors and total uncertainties, we evaluated the performance of four single outlier discordancy tests (Grubbs test N2, Dixon test N8, skewness test N14, and kurtosis test N15) for normal samples of sizes 5 to 20. Statistical contaminations of a single observation resulting from parameters called ? from 0.1 up to 20 for modeling the slippage of central tendency or ? from 1.1 up to 200 for slippage of dispersion, as well as no contamination (? = 0 and ? = 1), were simulated. Because of the use of precise and accurate random and normally distributed simulated data, very large replications, and a large number of independent experiments, this paper presents a novel approach for precise and accurate estimations of power functions of four popular discordancy tests and, therefore, should not be considered as a simple simulation exercise unrelated to probability and statistics. From both criteria of the Power of Test proposed by Hayes and Kinsella and the Test Performance Criterion of Barnett and Lewis, Dixon test N8 performs less well than the other three tests. The overall performance of these four tests could be summarized as N2?N15 > N14 > N8. PMID:24737992
16. Numerical simulation of combined natural and forced convection during thermal-hydraulic transients. [LMFBR
SciTech Connect
Domanus, H.M.; Sha, W.T.
1981-01-01
The single-phase COMMIX (COMponent MIXing) computer code performs fully three-dimensional, transient, thermal-hydraulic analyses of liquid-sodium LMFBR components. It solves the conservation equations of mass, momentum, and energy as a boundary-value problem in space and as an initial-value problem in time. The concepts of volume porosity, surface permeability and distributed resistance, and heat source have been employed in quasi-continuum (rod-bundle) applications. Results from three transient simulations involving forced and natural convection are presented: (1) a sodium-filled horizontal pipe initially of uniform temperature undergoing an inlet velocity rundown transient, as well as an inlet temperature transient; (2) a 19-pin LMFBR rod bundle undergoing a velocity transient; and, (3) a simulation of a water test of a 1/10-scale outlet plenum undergoing both velocity and temperature transients.
17. Ambiguity in measuring matrix diffusion with single-well injection/recovery tracer tests
USGS Publications Warehouse
Lessoff, S.C.; Konikow, L.F.
1997-01-01
Single-well injection/recovery tracer tests are considered for use in characterizing and quantifying matrix diffusion in dual-porosity aquifers. Numerical modeling indicates that neither regional drift in homogeneous aquifers, nor heterogeneity in aquifers having no regional drift, nor hydrodynamic dispersion significantly affects these tests. However, when drift is coupled simultaneously with heterogeneity, they can have significant confounding effects on tracer return. This synergistic effect of drift and heterogeneity may help explain irreversible flow and inconsistent results sometimes encountered in previous single-well injection/recovery tracer tests. Numerical results indicate that in a hypothetical single-well injection/recovery tracer test designed to demonstrate and measure dual-porosity characteristics in a fractured dolomite, the simultaneous effects of drift and heterogeneity sometimes yields responses similar to those anticipated in a homogeneous dual-porosity formation. In these cases, tracer recovery could provide a false indication of the occurrence of matrix diffusion. Shortening the shut-in period between injection and recovery periods may make the test less sensitive to drift. Using multiple tracers having different diffusion characteristics, multiple tests having different pumping schedules, and testing the formation at more than one location would decrease the ambiguity in the interpretation of test data.
18. Effects of high density dispersion fuel loading on the uncontrolled reactivity insertion transients of a low enriched uranium fueled material test research reactor
2009-01-01
The effects of using high density low enriched uranium on the uncontrolled reactivity insertion transients of a material test research reactor were studied. For this purpose, the low density LEU fuel of an MTR was replaced with high density UMo (9w\\/o) LEU fuels currently being developed under the RERTR program having uranium densities of 6.57gU\\/cm3, 7.74gU\\/cm3 and 8.57gU\\/cm3. Simulations were
19. Concept design and performance test of a magnetically suspended single-gimbal control moment gyro
NASA Astrophysics Data System (ADS)
Kito, Katsumi; Kanki, Hiroshi; Ishii, Shinya
Space vehicles are growing large in size and weight and attitude control systems require higher torque and momentum capability. As a primary attitude actuator for future platform type space vehicles, concept design model of a single-gimbal control moment gyro was built and tested. Based on the consideration of potential requirements for long life, low energy consumption, and vibration reduction, this concept design model adopts electromagnetic bearings which suspend two wheels. This single-gimbal control moment gyro has nominal angular momentum capacity of 100 Nms. The concept design model was tested and showed satisfactory results.
20. Measurement of LNAPL flux using single-well intermittent mixing tracer dilution tests.
PubMed
Smith, Tim; Sale, Tom; Lyverse, Mark
2012-01-01
The stability of subsurface Light Nonaqueous Phase Liquids (LNAPLs) is a key factor driving expectations for remedial measures at LNAPL sites. The conventional approach to resolving LNAPL stability has been to apply Darcy's Equation. This paper explores an alternative approach wherein single-well tracer dilution tests with intermittent mixing are used to resolve LNAPL stability. As a first step, an implicit solution for single-well intermittent mixing tracer dilution tests is derived. This includes key assumptions and limits on the allowable time between intermittent mixing events. Second, single-well tracer dilution tests with intermittent mixing are conducted under conditions of known LNAPL flux. This includes a laboratory sand tank study and two field tests at active LNAPL recovery wells. Results from the sand tank studies indicate that LNAPL fluxes in wells can be transformed into formation fluxes using corrections for (1) LNAPL thicknesses in the well and formation and (2) convergence of flow to the well. Using the apparent convergence factor from the sand tank experiment, the average error between the known and measured LNAPL fluxes is 4%. Results from the field studies show nearly identical known and measured LNAPL fluxes at one well. At the second well the measured fluxes appear to exceed the known value by a factor of two. Agreement between the known and measured LNAPL fluxes, within a factor of two, indicates that single-well tracer dilution tests with intermittent mixing can be a viable means of resolving LNAPL stability. PMID:22489832
1. Advanced sluicing system test report for single shell tank waste retrieval integrated testing
SciTech Connect
Berglin, E.J.
1997-05-29
This document describes the testing performed by ARD Environmental, Inc., and Los Alamos Technical Associates of the LATA/ARD Advanced Sluicing System, in support of ACTR Phase 1 activities. Testing was to measure the impact force and pressures of sluicing streams at three different distances, as measured by the Government supplied load cell. Simulated sluicing of large simulated salt cake and hard pan waste coupons was also performed. Due to operational difficulties experienced with the Government supplied load cell, no meaningful results with respect to sluice stream impact pressure distribution or stream coherence were obtained. Sluice testing using 3000 psi salt cake simulants measured waste retrieval rates of approximately 12 Ml/day (17.6 ft{sup 3}/hr). Rates as high as 314 m{sup 3}/day (463 ft{sup 3}/hr) were measured against the lower strength salt cake simulants.
2. Distinction between persistent and transient infection in a bovine viral diarrhoea (BVD) control programme: appropriate interpretation of real-time RT-PCR and antigen-ELISA test results.
PubMed
Hanon, J-B; Van der Stede, Y; Antonissen, A; Mullender, C; Tignon, M; van den Berg, T; Caij, B
2014-04-01
Control of bovine viral diarrhoea (BVD) in Belgium is currently implemented on a voluntary basis at herd level and mainly relies on detection and culling of persistently infected (PI) animals. The present field study was conducted during the winter of 2010/2011 to assess the performances of diagnostic assays used in the testing scheme for BVD as proposed by the two Belgian regional laboratories. Individual blood samples were collected from 4972 animals, and individual samples from the same herd were pooled (maximum of 30 individual samples per pool) and screened for the presence of Bovine Viral Diarrhoea Virus (BVDV)-specific RNA using a commercial real-time RT-PCR test (ADIAGENE). Individual samples from positive pools were then tested in parallel with the same RT-PCR test and with an antigen-capture ELISA test (IDEXX) to detect viremic animals. This study demonstrated that individual results differed according to the type of assay used (P<0.001): 140 animals (2.8%) were positive by RT-PCR and 72 (1.4%) by antigen-ELISA. A second blood sample was taken 40days later from 74 PCR positive animals to detect persistent viremia: 17 (23%) of these were still PCR positive and considered to be PI and the 57 that no longer tested positive were assumed to be transiently infected (TI) animals. All PI animals were positive also by antigen-ELISA at both time points. Among TI animals, 10 (16%) were positive by antigen-ELISA at the first but none at the second sampling. A highly significant difference in cycle threshold (Ct ) values obtained by RT-PCR was observed between PI and TI animals. ROC analysis was performed to establish thresholds to confirm with high probability that an animal is PI, based on the result of RT-PCR test performed on a single individual blood sample. PMID:23009318
3. In-flight and ground testing of single event upset sensitivity in static RAMs
SciTech Connect
Johansson, K.; Dyreklev, P.; Granbom, B. [Ericsson Saab Avionics AB, Linkoeping (Sweden)] [Ericsson Saab Avionics AB, Linkoeping (Sweden); Calvet, C. [Aerospatiale Space and Defence, Les Mureaux (France)] [Aerospatiale Space and Defence, Les Mureaux (France); Fourtine, S. [Aerospatiale Avions, Toulouse (France)] [Aerospatiale Avions, Toulouse (France); Feuillatre, O. [Dassault Electronique, Saint-Cloud (France)] [Dassault Electronique, Saint-Cloud (France)
1998-06-01
This paper presents the results from in-flight measurements of single event upsets (SEU) in static random access memories (SRAM) caused by the atmospheric radiation environment at aircraft altitudes. The memory devices were carried on commercial airlines at high altitude and mainly high latitudes. The SEUs were monitored by a Component Upset Test Equipment (CUTE), designed for this experiment. The in flight results are compared to ground based testing with neutrons from three different sources.
4. Quantum transients
E-print Network
A. del Campo; G. Garcia-Calderon; J. G. Muga
2009-05-16
Quantum transients are temporary features of matter waves before they reach a stationary regime. Transients may arise after the preparation of an unstable initial state or due to a sudden interaction or a change in the boundary conditions. Examples are diffraction in time, buildup processes, decay, trapping, forerunners or pulse formation, as well as other phenomena recently discovered, such as the simultaneous arrival of a wave peak at arbitrarily distant observers. The interest on these transients is nowadays enhanced by new technological possibilities to control, manipulate and measure matter waves.
5. Tests to Structural Collapse of Single Degree of Freedom Frames Subjected to Earthquake Excitations
E-print Network
Bruneau, Michel
. Introduction The arbitrary lateral drift limits prescribed by earthquake-resistant design codes to preventTests to Structural Collapse of Single Degree of Freedom Frames Subjected to Earthquake Excitations by currently used strength and stability axial-moment interaction design equations by expressing
6. Standardized Single-Disc MethodforAntibiotic Susceptibility Testing ofAnaerobic Bacteria
T. D. WILKINS; I. J. ABRAMSON; W. E. C. MOORE
1972-01-01
A method was developed fordetermination oftheantibiotic susceptibility ofanaero- bicbacteria byuse ofa single-disc diffusion technique andincorporation ofthe inoculum inpourplates. Themethod was standardized bycorrelation ofzone diam- eters withminimal inhibitory concentrations determined inbroth. Zonediameters could beusedtoapproximate theminimal inhibitory concentrations oftheseven antibiotics tested: ampicillin, bacitracin, carbenicillin, cephalothin, clindamycin, penicillin, andtetracycline. Anaerobic bacteria arebeing isolated from tissue infections withincreasing frequency as clinical anaerobic methods haveimproved.
7. Test results of a single aperture dipole model magnet for LHC
T. Shintomi; T. Nakamoto; N. Higashi; N. Kimura; T. Ogitsu; K. Tanaka; A. Terashima; K. Tsuchiya; A. Yamamoto; A. Orikasa; K. Makishima; N. Siegel; D. Leroy; R. Perin
1999-01-01
The 56 mm single aperture superconducting dipole model with a 5-block coil configuration was reassembled and tested to investigate the full support of electromagnetic forces using a high-manganese steel collar structure without mechanical contribution from an iron yoke. The reassembled model, which has a gap between the high manganese steel collar and the horizontally split iron yoke, reached a central
8. SINGLE PARTICLE IMPACT BREAKAGE CHARACTERIZATION OF MATERIALS BY DROP WEIGHT TESTING
mrden GEN; Levent ERGN; Hakan BENZER
2004-01-01
A drop weight tester was designed for the purpose of analyzing single particle impact breakage characteristics of different materials. Test results were evaluated through the breakage distributions of different size fractions at various impact energy levels. Breakage parameter t10 (Narayanan, 1986) is used to represent the degree of size reduction which is assumed to be represantative of the breakage product
9. Two interfacial shear strength calculations based on the single fiber composite test
S. F. Zhandarov; E. V. Pisanova
1996-01-01
The fragmentation of a single fiber embedded in a polymer matrix upon stretching (SFC test) provides valuable information on the fiber-matrix bond strength (t), which determines stress transfer through the interface and, thus, significantly affects the mechanical properties of the composite material. However, the calculated bond strength appears to depend on data interpretation, i.e., on the applied theoretical model, since
10. Generalized Single-Case Randomization Tests: Flexible Analyses for a Variety of Situations.
ERIC Educational Resources Information Center
Levin, Joel R.; Wampold, Bruce E.
1999-01-01
Presents a general class of single-case statistical procedures derived from previously developed nonparametric randomization tests. Designs are illustrated that focus on the general and comparative effectiveness of alternative interventions, multiple units with differentiable characteristics, and multiple outcome measures. Provides operational
11. ANALYSIS AND INTERPRETATION OF SINGLE-WELL TRACER TESTS IN STRATIFIED AQUIFERS
EPA Science Inventory
The study deals with the definition and measurement of the dispersive properties of aquifers. Knowledge of such dispersive properties are of fundamental importance to the evaluation, analysis, and simulation of contaminant migration in groundwater. In the single-well test describ...
12. Real-data tests of a single-Doppler radar assimilation system
Thomas Nehrkorn; James Hegarty; Thomas M. Hamill
1994-01-01
Real data tests of a single-Doppler radar data assimilation and forecast system have been conducted for a Florida sea breeze case. The system consists of a hydrostatic mesoscale model used for prediction of the preconvective boundary layer, an objective analysis that combines model first guess fields with radar derived horizontal winds, a thermodynamic retrieval scheme that obtains temperature information from
13. Interfacial studies of natural fibre\\/polypropylene composites using single fibre fragmentation test (SFFT)
A. Awal; G. Cescutti; S. B. Ghosh; J. Mssig
2011-01-01
For the potential use and new applications of natural fibre reinforced plastics, it is crucial that the mechanical behaviour of these composites is fully understood. Single fibre fragmentation tests (SFFT) were carried out to compare the fragmentation phenomenon in two natural fibres\\/polypropylene (PP) composites. Polypropylene was used with maleic anhydride (MAPP) as a coupling agent for this study. The SFFT
14. The characterization of carbon nanotube infused glass fibers by single filament fragmentation test methods
NASA Astrophysics Data System (ADS)
Roach, Andrew Michael
Single filament fragmentation tests were completed for individual glass fibers with varying surface treatments and carbon nanostructure infusions. Fiber fragmentation was analyzed by embedding a single filament into a standard tensile interface, which provided shear stress transfer between a conventional epoxy resin system and the constituent filament. Established single filament fragmentation techniques were used to characterize fiber and interface properties. A novel method of comparing fibers is introduced by correlating bundle tow test results to fiber fragmentation critical length data to qualitatively relate fiber performance. Photoelastic birefringent stress fringes were processed at select fiber fragmentation locations to further characterize the fiber-resin, or fiber-carbon nanostructure-resin, interface. Overall, the performance matrix qualitative comparison method, coupled with stress fringe analysis, proved to be an effective means of qualitatively evaluating fiber and processing parameters, and efficiently identifies the most fruitful path forward for optimized fiber development.
15. Depression in black single mothers: a test of a theoretical model.
PubMed
Atkins, Rahshida
2015-06-01
The aim of this study was to test a theoretical model of depression for Black single mothers. Participants were 208 Black single mothers, aged 18 to 45, recruited from community settings. The a priori over-identified recursive theoretical model was tested via the LISREL 9.1 program using a maximum likelihood estimation for structural equation modeling. The chi-square indicated that there was an excellent fit of the model with the data, ?(2)(1, N = 208) = .05, p = .82. The fit indices for the model were excellent. Path coefficients were statistically significant for seven out of eight of the direct paths within the model (p < .05). The two indirect paths were also statistically significant. The theory was supported and can be applied by health care professionals when working with depressed Black single mothers. PMID:24709854
16. Transient hydraulic tomography in a sandbox with deterministic heterogeneity: Validation of hydraulic conductivity and specific storage tomograms
NASA Astrophysics Data System (ADS)
Liu, X.; Illman, W. A.; Craig, A. J.
2005-12-01
Hydraulic tomography is a method that images the hydraulic heterogeneity of the subsurface through the inversion of multiple pumping test data. Transient hydraulic tomography differentiates itself from steady-state tomography in that it not only estimates hydraulic conductivity but also provides an estimate of specific storage. Since it adopts transient pumping test data, it utilizes more data from each pumping test than steady-state tomography. Here, we investigate the information content of transient drawdown data through the analysis of synthetic and laboratory pumping test data in a 2-dimensional sandbox. In a synthetic study, pumping tests are performed on a computer model and the data generated is then used in the inversion. For the laboratory sandbox studies, pumping tests are performed on a physical sandbox model with deterministic heterogeneity. The data generated from these "real" tests are then used for transient inversions. To validate the tomograms, we utilize other hydraulic tests conducted at multiple scales in the sandbox such as permeameter tests on extracted cores, slug tests, single-hole tests, cross-hole tests and large-scale pumping tests. Validation consists of: 1) comparing local hydraulic conductivity and specific storage values from independent hydraulic tests to local values from transient hydraulic tomography; and 2) comparing the statistical moments of hydraulic conductivity and specific storage from the inverse model to those from other measurements. After validation of the results, we examine the information content of transient drawdown data by comparing the early, intermediate and late stages of drawdown data and the corresponding tomograms resulting from these data. We also compare the transient results with the hydraulic conductivity distribution from previously conducted steady-state hydraulic tomography to examine whether transient pumping data can improve the quality of the hydraulic conductivity tomograms. Finally, we use the hydraulic conductivity and specific storage tomograms from transient hydraulic tomography to predict the drawdown curves of other pumping tests that we did not use in the inversion.
17. ?1H mRNA in single skeletal muscle fibres accounts for T-type calcium current transient expression during fetal development in mice
PubMed Central
Berthier, Christine; Monteil, Arnaud; Lory, Philippe; Strube, Caroline
2002-01-01
Calcium channels are essential for excitation-contraction coupling and muscle development. At the end of fetal life, two types of Ca2+ currents can be recorded in muscle cells. Whereas L-type Ca2+ channels have been extensively studied, T-type channels have been poorly characterized in skeletal muscle. We describe here the functional and molecular properties of T-type calcium channels in developing mouse skeletal muscle. The T-type current density increased transiently during prenatal myogenesis with a maximum at embryonic day E16 followed by a drastic decrease until birth. This current showed similar electrophysiological and pharmacological properties at all examined stages. It displayed a wide window current centred at about ?35 and ?55 mV in 10 and 2 mm external Ca2+, respectively. Activation and inactivation kinetics were fast (3 and 16 ms, respectively). The current was inhibited by nickel and amiloride with an IC50 of 5.4 and 156 ?m, respectively, values similar to those described for cloned T-type ?1H channels. Whole muscle tissue RT-PCR analysis revealed mRNAs corresponding to ?1H and ?1G subunits in the fetus but not in the adult. However, single-fibre RT-PCR demonstrated that only ?1H mRNA was present in prenatal fibres, suggesting that the ?1G transcript present in muscle tissue must be expressed by non-skeletal muscle cells. Altogether, these results demonstrate that the ?1H subunit generates functional T-type calcium channels in developing skeletal muscle fibres and suggest that these channels are involved in the early stages of muscle differentiation. PMID:11897840
18. Testing the Kerr-nature of stellar-mass black hole candidates by combining the continuum-fitting method and the power estimate of transient ballistic jets
E-print Network
Cosimo Bambi
2012-01-25
Astrophysical black hole candidates are thought to be the Kerr black holes predicted by General Relativity, as these objects cannot be explained otherwise without introducing new physics. However, there is no observational evidence that the space-time around them is really described by the Kerr solution. The Kerr black hole hypothesis can be tested with the already available X-ray data by extending the continuum-fitting method, a technique currently used by astronomers to estimate the spins of stellar-mass black hole candidates. In general, we cannot put a constraint on possible deviations from the Kerr geometry, but only on some combination between these deviations and the spin. The measurement of the radio power of transient jets in black hole binaries can potentially break this degeneracy, thus allowing for testing the Kerr-nature of these objects.
19. Corrected transient energy function and transient stability limit assessment
T. S. Chung; D. Z. Fang
2000-01-01
This paper reports the developments in the methodology for analysis of transient stability limit conditions. Concepts, including corrected potential energy and corrected potential energy boundary surface, are presented. Efficient criteria in identifying first swing stability behavior are also developed and used in hybrid method incorporating corrected transient energy margin (CTEM) analysis. Test results on real size power systems, such as
20. Tracer Tests in a Fractured Dolomite: 3. Analysis of Mass Transfer in Single-Well Injection-Withdrawal Tests
SciTech Connect
Haggerty, R.; Fleming, S.W.; Meigs, L.C.; McKenna, S.A.
1999-03-04
We investigated multiple-rate diffusion as a possible explanation for observed behavior in a suite of single-well injection-withdrawal (SWIW) tests conducted in a fractured dolomite. We first investigated the ability of a conventional double-porosity model and a multirate diffusion model to explain the data. This revealed that the multirate diffusion hypothesis/model is most consistent with all available data, and is the only model to date that is capable of matching each of the recovery curves entirely. Second, we studied the sensitivity of the SWIW recovery curves to the distribution of diffusion rate coefficients and other parameters. We concluded that the SWIW test is very sensitive to the distribution of rate coefficients, but is relatively insensitive to other flow and transport parameters such as advective porosity and dispersivity. Third, we examined the significance of the constant double-log late-time slopes ({minus}2. 1 to {minus}2.8), which are present in several data sets. The observed late-time slopes are significantly different than would be predicted by either conventional double-porosity or single-porosity media, and are found to be a distinctive feature of multirate diffusion under SWIW test conditions. Fourth, we found that the estimated distributions of diffusion rate coefficients are very broad, with the distributions spanning a range of at least 3.6 to 5.7 orders of magnitude.
1. Experimental test of theories of the detection mechanism in a nanowire superconducting single photon detector.
PubMed
Renema, J J; Gaudio, R; Wang, Q; Zhou, Z; Gaggero, A; Mattioli, F; Leoni, R; Sahin, D; de Dood, M J A; Fiore, A; van Exter, M P
2014-03-21
We report an experimental test of the photodetection mechanism in a nanowire superconducting single photon detector. Detector tomography allows us to explore the 0.8-8 eV energy range via multiphoton excitations. High accuracy results enable a detailed comparison of the experimental data with theories for the mechanism of photon detection. We show that the temperature dependence of the efficiency of the superconducting single photon detector is determined not by the critical current but by the current associated with vortex unbinding. We find that both quasiparticle diffusion and vortices play a role in the detection event. PMID:24702419
2. Lightning transient interaction control
E. F. Vance; J. E. Nanevicz
1982-01-01
Transient or broadband interference from such sources outside an aircraft as lightning strikes can be controlled, through the application of topologically closed electromagnetic barriers. The appropriate choice of barrier configurations can reduce maintenance, increase reliability, and simplify specification and testing at the subsystem level. The appropriate allocation procedures can yield intrasystem compatibility, as well as immunity to lightning strikes.
3. A Compendium of Recent Optocoupler Radiation Test Data
NASA Technical Reports Server (NTRS)
Label, K. A.; Kniffin, S. D.; Reed, R. A.; Kim, H. S.; Wert, J. L.; Oberg, D. L.; Normand, E.; Johnston, A. H.; Lum, G. K.; Koga, R.; Day, John H. (Technical Monitor)
2000-01-01
We present a compendium of optocoupler radiation test data including neutron, proton and heavy ion Displacement Damage (DD), Single Event Transients (SET) and Total Ionizing Dose (TID). Proton data includes ionizing and non-ionizing damage mechanisms.
4. Testing a new automated single ring infiltrometer for Beerkan infiltration experiments
NASA Astrophysics Data System (ADS)
Di Prima, Simone; Lassabatre, Laurent; Angulo-Jaramillo, Rafael; Bagarello, Vincenzo; Iovino, Massimo
2015-04-01
The Beerkan method along with BEST algorithms is an alternative technique to conventional laboratory or field measurements for rapid and low-cost estimation of soil hydraulic properties. The Beerkan method is simple to conduct but requires an operator to pour known volumes of water through the ring and can be time-consuming. To alleviate this need, a new cheap infiltrometer equipped with a data acquisition system, allowing automation of Beerkan infiltration experiments, was recently designed and is presented in a companion paper. Yet, it has never been tested against a wide range of experimental conditions (soils, initial water saturation, etc.). In this paper, we tested the automated infiltrometer with the aim to validate its applicability to the Beerkan infiltration experiment under several experimental circumstances. In addition, we assessed the accuracy of BEST methods on the data obtained with the infiltrometer for the estimation of saturated soil hydraulic conductivity and sorptivity. For this purpose, we used both analytically generated and real experimental data. The analytically generated data simulate infiltration experiments carried out with the infiltrometer on five contrasting soils from UNSODA database and different initial water contents. The total volume of water to be infiltrated and the volume increments are fixed by the infiltrometer characteristics. Then, inverse analysis of the analytically generated data was performed using the three available BEST algorithms to derive saturated soil hydraulic conductivity and sorptivity that were compared to the reference values. The results of the analytical assessment showed that the infiltrometer along with BEST methods could lead to accurate estimates in most cases thus validating the design of the studied infiltrometer and its combination with BEST algorithms. Some soils (mostly loam) and some hydric conditions (high initial water contents) may lead to misestimate soil properties or failure of BEST algorithms according to numerical results. In these cases, the failures are due to the fact that steady state is not properly reached or the transient state is not properly described (not enough points in the transient state). Finally, the infiltrometer was tested in different soil types. All experiments were carried in an infiltration basin located in the pumping well filed of Crpieux-Charmy, which provides drinking water for the Lyon metropolitan area. Water infiltration experiments were conducted on the subsoil, the layer of sand embedded at surface, either clean or clogged. Experiments and analysis with BEST algorithms proved efficient to pinpoint the decrease in hydraulic conductivity due to clogging. The experiments showed that the automatic data collection increases measurement speeds and allows for more efficient data handling and analysis.
5. High-Gradient Tests of the Single-Cell SC Cavity with a Feedback Waveguide
SciTech Connect
Yakovlev, V.; Solyak, N.; Wu, G.; Ge, M.; Gonin, I.; Khabiboulline, T.; Ozelis, J.; Rowe, A. [Fermilab, Batavia, IL 60510 (United States); Avrakhov, P.; Kanareykin, A. [Euclid TechLabs, LLC, Solon, Ohio 44139 (United States); Rathke, J. [AES, Medford, NY 11763 (United States)
2010-11-04
Use of a superconducting (SC) traveling-wave accelerating (STWA) structure with a small phase advance per cell, rather than a standing-wave structure, may provide a significant increase in the accelerating gradient in the ILC linac [1]. For the same surface electric and magnetic fields, the STWA achieves an accelerating gradient 1.2 larger than TESLA-like standing-wave cavities. In addition, the STWA allows longer acceleration cavities, reducing the number of gaps between them. However, the STWA structure requires a SC feedback waveguide to return the few hundreds of MW of circulating RF power from the structure output to the structure input. A test single-cell cavity with feedback was designed and manufactured to demonstrate the possibility of proper processing to achieve a high accelerating gradient. The first results of high-gradient tests of a prototype 1.3 GHz single-cell cavity with feedback waveguide will be presented.
6. Progressive vs single-stage treadmill tests for evaluation of claudication.
PubMed
Gardner, A W; Skinner, J S; Cantwell, B W; Smith, L K
1991-04-01
The reliability of claudication pain and the metabolic and hemodynamic measurements of the lower limbs of patients with stable peripheral vascular occlusive disease (PVOD) were compared during and following single-stage (S) and progressive (P) treadmill tests. Ten patients (69.8 +/- 1.8 yr; X +/- SE) walked to maximal claudication pain twice a month for 4 months. Patients walked at 1.5 mph up a 7.5% grade (S test) and at 2 mph on a 0% grade, increasing by 2% every 2 min (P test). Distance walked to the onset of claudication pain (CPD) and maximal walking distance (MWD) were recorded. Foot transcutaneous oxygen tension (TcPO2) was measured before, during, and after exercise, while ankle systolic blood pressure (SBP) and the ankle-to-brachial SBP index (ABI) were measured before and after exercise. Intraclass correlation coefficients (R) of CPD and MWD during S tests were R = 0.53 and R = 0.55, respectively. In contrast, the respective R values during P tests were R = 0.89 and R = 0.93. Higher R values of foot TcPO2 were also obtained during and following P tests, while ankle SBP and ABI were highly reliable following both tests. It is concluded that the severity of PVOD is better assessed by P treadmill tests because clinical measurements are more reliable during exercise and recovery. PMID:2056896
7. High gradient test of the HINS SSR1 single spoke resonator
SciTech Connect
Gonin, I.; Khabibouline, T.; Lanfranco, G.; Mukherjee, A.; Ozelis, JH.; Ristori, L.; Sergatskov, A.; Wagner, R.; Webber, R.; /Fermilab
2008-09-01
Eighteen {beta} = 0.21 superconducting single spoke resonators comprise the first state in the cold section of the 8-GeV H{sup -} Linac for Fermilab's proposed Project X. After Buffered Chemical Polishing and High Pressure Rinse, one resonator has undergone high gradient RF testing at 2.0-4.5 K in the Vertical Test Stand at Fermilab. They present measurements of the surface resistance as a function of temperature and the quality factor as a function of accelerating field. The resonator reached an accelerating field of 18.0 MV/m.
8. A Testing Approach for MOS Circuit Using Single-Photon Detectors Under High Magnetic Fields
NASA Astrophysics Data System (ADS)
Pan, Zhongliang; Chen, Ling; Chen, Junfang; Zhang, Guangzhao; Wu, Peiheng
2013-03-01
The MOS circuits must be tested thoroughly for insuring the reliability. A new testing approach for MOS circuits is presented in this paper, which makes use of single-photon detectors and high magnetic fields. If there are faults in the circuit under test, the photon emission from the circuit components is detected by a single-photon detector, the faults are located by the amount of the emitted photons. The following two techniques are proposed in this paper. First, the high magnetic field is applied to the circuit under test, i.e., the circuit is put in high magnetic field environment. To some extent this technique can solve the problem that some faults have poor strengths of emitted photons under general environment. Second, the special circuit input vectors are designed by using binary decision diagrams. The input vectors can make the positions of circuit components to produce signal transitions or switching behaviors, therefore the photon emission strengths of circuit components are enhanced. A lot of experimental results show that the faults in MOS circuits can be tested accurately by the approach proposed in this paper.
9. Study of the comminution characteristics of coal by single particle breakage test device
SciTech Connect
Sahoo, R. [University of Central Queensland, Rockhampton, Qld. (Australia)
2005-09-01
Single-particle breakage tests of South Blackwater and Ensham coal from the Bowen Basin area in Queensland were conducted by a computer-monitored twin-pendulum device to measure the energy utilization pattern of the breakage particles. Three particle sizes (-16.0+13.2mm, -13.2+11.2mm, -11.2+9.5mm) of each coal were tested by a pendulum device at five input energy levels to measure the specific comminution energy. When particles were tested at constant input energy, the variation of comminution energy between the same size broken particles of Ensham coal was minimal, because Ensham coal is a softer and higher friability coal, which absorbs more input energy than harder coal during breakage tests. For different particle sizes, the specific comminution energy increases linearly with the input energy and the fineness of the breakage products increases with the specific comminution energy. The size distribution graphs are curved but approach linearity in the finer region. At a constant input energy, the twin pendulum breakage product results show that the fineness of the products increases with decrease in particle size and South Blackwater coal produced finer products than the Ensham coal. The t-curves are the family of size distribution curves, which can describe the product size distribution of the breakage particles during single-particle breakage tests.
10. Comparing ecotoxicological effect concentrations of chemicals established in multi-species vs. single-species toxicity test systems.
PubMed
De Laender, Frederik; De Schamphelaere, Karel A C; Vanrolleghem, Peter A; Janssen, Colin R
2009-02-01
Most ecological effect assessment methodologies use effect concentrations derived from single-species testing (ECx,single-species-test) as the basis to estimate 'safe' environmental concentrations (such as environmental quality criteria). Here, we examined to what extent such ECx,single-species-test are representative for population-level effect concentrations in a community setting (ECx,multi-species-test). Data from USEPA's ECOTOX database revealed the existence of considerable scatter around the relationship between ECx,single-species-test (endpoint: mortality) and ECx,multi-species-test (endpoint: population abundance). However, we demonstrate that this scatter is reduced when ECx,single-species-test and ECx,multi-species-test are determined simultaneously and by the same research group. Indeed, if these conditions are fulfilled, the quotient of both ECx values for invertebrates approaches 1 for chemicals that directly target invertebrates. Unfortunately, comparable data for other classes of chemicals and/or taxonomic groups were not found. However, theoretical ecosystem model simulations, which confirmed the results based on the above-mentioned analysis of the ECOTOX database, indicated that for phytoplankton, EC10,single-species-test>EC10,multi-species-test, for chemicals that directly target invertebrates. For chemicals that directly target phytoplankton, the ecosystem model simulations suggest that ECx,single-species-test>ECx,multi-species-test for both phytoplankton and invertebrates. Hence, our observation based on the analysis of existing experimental data that the ECx,single-species-test is similar to the ECx,multi-species-test may be biased by the fact that only data were available for invertebrates and for chemicals targeting invertebrates. Experimental research is required to test the predictions made by the model simulations for phytoplankton as well as for chemicals directly targeting phytoplankton. PMID:18774172
11. Optimization of single-yoke magnetic testing by surface fields measurement
Oleksandr Stupakov; Ivan Toms; Jana Kadlecov
2006-01-01
The main aim of the work is to discuss ways of optimizing a single-yoke magnetization set-up with respect to fluctuations of the measurement results due to imperfections of the yoke-sample contact. The nondestructive testing method is proposed to be optimized by simultaneous multi-point determination of surface magnetic fields of the investigated sample. The presented measurements of the surface fields are
12. Optimization of single-yoke magnetic testing by surface flelds measurement
Oleksandr Stupakovy; Ivan Tomas; Jana Kadlecova
The main aim of the work is to discuss ways of optimization of single-yoke magnetization set-up with respect to ?uctuations of the measurement results due to imperfections of the yoke-sample contact. The nondestructive testing method is proposed to be optimized by simultaneous multi-point determination of surface magnetic flelds of the investigated sample. The presented measurements of the surface flelds are
13. Optimization of single-yoke magnetic testing by surface fields measurement
NASA Astrophysics Data System (ADS)
Stupakov, Oleksandr; Toms, Ivan; Kadlecov, Jana
2006-01-01
The main aim of the work is to discuss ways of optimizing a single-yoke magnetization set-up with respect to fluctuations of the measurement results due to imperfections of the yoke-sample contact. The nondestructive testing method is proposed to be optimized by simultaneous multi-point determination of surface magnetic fields of the investigated sample. The presented measurements of the surface fields are accompanied by computational modelling of the magnetic system by the finite element method.
14. An end-effect model for the single-filament tensile test
E. G. Stoner; D. D. Edie; S. D. Durham
1994-01-01
The effect of cross-sectional shape on tensile strength of pitch-based carbon fibres was investigated by extensive single-filament testing. For this study, round and trilobal pitch-based carbon fibres were produced at similar processing conditions. The application of a variety of distributions, including the simple Weibull distribution, to the strength data indicated two sources of failure, one source being the accentuation of
15. Statistical searches for microlensing events in large, non-uniformly sampled time-domain surveys: A test using palomar transient factory data
SciTech Connect
Price-Whelan, Adrian M.; Ageros, Marcel A. [Department of Astronomy, Columbia University, 550 W 120th Street, New York, NY 10027 (United States); Fournier, Amanda P. [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93106 (United States); Street, Rachel [Las Cumbres Observatory Global Telescope Network, Inc., 6740 Cortona Drive, Suite 102, Santa Barbara, CA 93117 (United States); Ofek, Eran O. [Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel); Covey, Kevin R. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Levitan, David; Sesar, Branimir [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Laher, Russ R.; Surace, Jason, E-mail: [email protected] [Spitzer Science Center, California Institute of Technology, Mail Stop 314-6, Pasadena, CA 91125 (United States)
2014-01-20
Many photometric time-domain surveys are driven by specific goals, such as searches for supernovae or transiting exoplanets, which set the cadence with which fields are re-imaged. In the case of the Palomar Transient Factory (PTF), several sub-surveys are conducted in parallel, leading to non-uniform sampling over its ?20,000 deg{sup 2} footprint. While the median 7.26 deg{sup 2} PTF field has been imaged ?40 times in the R band, ?2300 deg{sup 2} have been observed >100 times. We use PTF data to study the trade off between searching for microlensing events in a survey whose footprint is much larger than that of typical microlensing searches, but with far-from-optimal time sampling. To examine the probability that microlensing events can be recovered in these data, we test statistics used on uniformly sampled data to identify variables and transients. We find that the von Neumann ratio performs best for identifying simulated microlensing events in our data. We develop a selection method using this statistic and apply it to data from fields with >10 R-band observations, 1.1 10{sup 9} light curves, uncovering three candidate microlensing events. We lack simultaneous, multi-color photometry to confirm these as microlensing events. However, their number is consistent with predictions for the event rate in the PTF footprint over the survey's three years of operations, as estimated from near-field microlensing models. This work can help constrain all-sky event rate predictions and tests microlensing signal recovery in large data sets, which will be useful to future time-domain surveys, such as that planned with the Large Synoptic Survey Telescope.
16. Classifying performance impairment in response to sleep loss using pattern recognition algorithms on single session testing
PubMed Central
St. Hilaire, Melissa A.; Sullivan, Jason P.; Anderson, Clare; Cohen, Daniel A.; Barger, Laura K.; Lockley, Steven W.; Klerman, Elizabeth B.
2012-01-01
There is currently no gold standard marker of cognitive performance impairment resulting from sleep loss. We utilized pattern recognition algorithms to determine which features of data collected under controlled laboratory conditions could most reliably identify cognitive performance impairment in response to sleep loss using data from only one testing session, such as would occur in the real world or field conditions. A training set for testing the pattern recognition algorithms was developed using objective Psychomotor Vigilance Task (PVT) and subjective Karolinska Sleepiness Scale (KSS) data collected from laboratory studies during which subjects were sleep deprived for 26 52 hours. The algorithm was then tested in data from both laboratory and field experiments. The pattern recognition algorithm was able to identify performance impairment with a single testing session in individuals studied under laboratory conditions using PVT, KSS, length of time awake and time of day information with sensitivity and specificity as high as 82%. When this algorithm was tested on data collected under real-world conditions from individuals whose data were not in the training set, accuracy of predictions for individuals categorized with low performance impairment were as high as 98%. Predictions for medium and severe performance impairment were less accurate. We conclude that pattern recognition algorithms may be a promising method for identifying performance impairment in individuals using only current information about the individuals behavior. Single testing features (e.g., number of PVT lapses) with high correlation with performance impairment in the laboratory setting may not be the best indicators of performance impairment under real-world conditions. Pattern recognition algorithms should be further tested for their ability to be used in conjunction with other assessments of sleepiness in real-world conditions to quantify performance impairment in response to sleep loss. PMID:22959616
17. The LOFAR Transients Pipeline
NASA Astrophysics Data System (ADS)
Swinbank, John D.; Staley, Tim D.; Molenaar, Gijs J.; Rol, Evert; Rowlinson, Antonia; Scheers, Bart; Spreeuw, Hanno; Bell, Martin E.; Broderick, Jess W.; Carbone, Dario; Garsden, Hugh; van der Horst, Alexander J.; Law, Casey J.; Wise, Michael; Breton, Rene P.; Cendes, Yvette; Corbel, Stphane; Eislffel, Jochen; Falcke, Heino; Fender, Rob; Griemeier, Jean-Mathias; Hessels, Jason W. T.; Stappers, Benjamin W.; Stewart, Adam J.; Wijers, Ralph A. M. J.; Wijnands, Rudy; Zarka, Philippe
2015-06-01
Current and future astronomical survey facilities provide a remarkably rich opportunity for transient astronomy, combining unprecedented fields of view with high sensitivity and the ability to access previously unexplored wavelength regimes. This is particularly true of LOFAR, a recently-commissioned, low-frequency radio interferometer, based in the Netherlands and with stations across Europe. The identification of and response to transients is one of LOFAR's key science goals. However, the large data volumes which LOFAR produces, combined with the scientific requirement for rapid response, make automation essential. To support this, we have developed the LOFAR Transients Pipeline, or TraP. The TraP ingests multi-frequency image data from LOFAR or other instruments and searches it for transients and variables, providing automatic alerts of significant detections and populating a lightcurve database for further analysis by astronomers. Here, we discuss the scientific goals of the TraP and how it has been designed to meet them. We describe its implementation, including both the algorithms adopted to maximize performance as well as the development methodology used to ensure it is robust and reliable, particularly in the presence of artefacts typical of radio astronomy imaging. Finally, we report on a series of tests of the pipeline carried out using simulated LOFAR observations with a known population of transients.
18. Robotic Searching for Stationary, Unknown and Transient Radio Sources
E-print Network
Kim, Chang Young
2012-07-16
of the transient target localization problem such as Single Robot Single Target (SRST), Multiple Robots Single Target (MRST), Single Robot Multiple Targets (SRMT) and Multiple Robots Multiple Targets (MRMT). We propose the expected searching time (EST) as a primary...
19. A Neutrality Test for Detecting Selection on DNA Methylation Using Single Methylation Polymorphism Frequency Spectrum
PubMed Central
Wang, Jun; Fan, Chuanzhu
2015-01-01
Inheritable epigenetic mutations (epimutations) can contribute to transmittable phenotypic variation. Thus, epimutations can be subject to natural selection and impact the fitness and evolution of organisms. Based on the framework of the modified Tajimas D test for DNA mutations, we developed a neutrality test with the statistic Dm to detect selection forces on DNA methylation mutations using single methylation polymorphisms. With computer simulation and empirical data analysis, we compared the Dm test with the original and modified Tajimas D tests and demonstrated that the Dm test is suitable for detecting selection on epimutations and outperforms original/modified Tajimas D tests. Due to the higher resetting rate of epimutations, the interpretation of Dm on epimutations and Tajimas D test on DNA mutations could be different in inferring natural selection. Analyses using simulated and empirical genome-wide polymorphism data suggested that genes under genetic and epigenetic selections behaved differently. We applied the Dm test to recently originated Arabidopsis and human genes, and showed that newly evolved genes contain higher level of rare epialleles, suggesting that epimutation may play a role in origination and evolution of genes and genomes. Overall, we demonstrate the utility of the Dm test to detect whether the loci are under selection regarding DNA methylation. Our analytical metrics and methodology could contribute to our understanding of evolutionary processes of genes and genomes in the field of epigenetics. The Perl script for the Dm test is available at http://fanlab.wayne.edu/ (last accessed December 18, 2014). PMID:25539727
20. A rapid antimicrobial susceptibility test based on single-cell morphological analysis.
PubMed
Choi, Jungil; Yoo, Jungheon; Lee, Mincheol; Kim, Eun-Geun; Lee, Ji Soo; Lee, Seungok; Joo, Seik; Song, Sang Hoon; Kim, Eui-Chong; Lee, Jung Chan; Kim, Hee Chan; Jung, Yong-Gyun; Kwon, Sunghoon
2014-12-17
A rapid antibiotic susceptibility test (AST) is desperately needed in clinical settings for fast and appropriate antibiotic administration. Traditional ASTs, which rely on cell culture, are not suitable for urgent cases of bacterial infection and antibiotic resistance owing to their relatively long test times. We describe a novel AST called single-cell morphological analysis (SCMA) that can determine antimicrobial susceptibility by automatically analyzing and categorizing morphological changes in single bacterial cells under various antimicrobial conditions. The SCMA was tested with four Clinical and Laboratory Standards Institute standard bacterial strains and 189 clinical samples, including extended-spectrum ?-lactamase-positive Escherichia coli and Klebsiella pneumoniae, imipenem-resistant Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and vancomycin-resistant Enterococci from hospitals. The results were compared with the gold standard broth microdilution test. The SCMA results were obtained in less than 4 hours, with 91.5% categorical agreement and 6.51% minor, 2.56% major, and 1.49% very major discrepancies. Thus, SCMA provides rapid and accurate antimicrobial susceptibility data that satisfy the recommended performance of the U.S. Food and Drug Administration. PMID:25520395
1. Are single-well "push-pull" tests suitable tracer methods for aquifer characterization?
NASA Astrophysics Data System (ADS)
Hebig, Klaus; Zeilfelder, Sarah; Ito, Narimitsu; Machida, Isao; Scheytt, Traugott; Marui, Atsunao
2013-04-01
Recently, investigations were conducted for geological and hydrogeological characterisation of the sedimentary coastal basin of Horonobe (Hokkaido, Japan). Coastal areas are typical geological settings in Japan, which are less tectonically active than the mountain ranges. In Asia, and especially in Japan, these areas are often densely populated. Therefore, it is important to investigate the behaviour of solutes in such unconsolidated aquifers. In such settings sometimes only single boreholes or groundwater monitoring wells are available for aquifer testing for various reasons, e.g. depths of more than 100 m below ground level and slow groundwater velocities due to density driven flow. A standard tracer test with several involved groundwater monitoring wells is generally very difficult or even not possible at these depths. One of the most important questions in our project was how we can obtain information about chemical and hydraulic properties in such aquifers. Is it possible to characterize solute transport behaviour parameters with only one available groundwater monitoring well or borehole? A so-called "push-pull" test may be one suitable method for aquifer testing with only one available access point. In a push-pull test a known amount of several solutes including a conservative tracer is injected into the aquifer ("push") and afterwards extracted ("pull"). The measured breakthrough curve during the pumping back phase can then be analysed. This method has already been used previously with various aims, also in the recent project (e.g. Hebig et al. 2011, Zeilfelder et al. 2012). However, different test setups produced different tracer breakthrough curves. As no systematic evaluation of this aquifer tracer test method was done so far, nothing is known about its repeatability. Does the injection and extraction rate influence the shape of the breakthrough curve? Which role plays the often applied "chaser", which is used to push the test solution out from the borehole and gravel pack? How does density difference between the original groundwater and the test solution influence the tracer breakthrough curves? To solve these questions, seven push-pull tests were performed under controlled boundary conditions in the same well DD-2 (100 m depth). Only single parameters, as e.g. flow rate or salinization of the test solution, were varied during the experiments. By conducting these different test setups, conclusions could be drawn about the application of the push-pull method under different settings. References: Hebig, K.H., Ito, N., Scheytt, T.J. & Marui, A. (2011). Hydraulic and hydrochemical characterization of deep coastal sedimentary basins by single-well Push-Pull tests. GSA Annual Meeting, 9-12 October 2011, Minneapolis, USA. Zeilfelder, S., Ito, N., Marui, A., Hebig, K. & Scheytt, T. (2012). Push-Pull-Test und Tracer-Test in ei-nem tiefen Grundwasserleiter in Kameoka, Japan. Kurzfassung in: Liedl, R., Burghardt, D., Simon, E., Reimann, T. & Kaufmann-Knoke (Hg.). Grundwasserschutz und Grundwassernutzung. Tagung der Fachsektion Hydrogeologie in der DGG (FH-DGG). 16. - 20. Mai 2012, Dresden. Kurfassungen der Vortrge und Poster. Schriftenreihe der DGG, Heft 78, S. 192.
2. Testing for Suspected Impairments and Dissociations in Single-Case Studies in Neuropsychology: Evaluation of Alternatives Using Monte Carlo Simulations and Revised Tests for Dissociations
John R. Crawford; Paul H. Garthwaite
2005-01-01
In neuropsychological single-case studies, a patient is compared with a small control sample. Methods of testing for a deficit on Task X, or a significant difference between Tasks X and Y, either treat the control sample statistics as parameters (using z and zD) or use modified t tests. Monte Carlo simulations demonstrated that if z is used to test for
3. Infrastructure Development of Single Cell Testing Capability at A0 Facility
SciTech Connect
Dhanaraj, Nandhini; Padilla, R.; Reid, J.; Khabiboulline, T.; Ge, M.; Mukherjee, A.; Rakhnov, I.; Ginsburg, C.; Wu, G.; Harms, E.; Carter, H.; /Fermilab
2009-09-01
The objective of this technical note is to document the details of the infrastructure development process that was realized at the A0 photo injector facility to establish RF cold testing capability for 1.3 GHz superconducting niobium single cell cavities. The activity began the last quarter of CY 2006 and ended the first quarter of CY 2009. The whole process involved addressing various aspects such as design of vertical insert and lifting fixture, modification of existing RF test station and design of new couplers, development of a Temperature Mapping (T-Map) system, radiation considerations for the test location (north cave), update of existing High Pressure Rinse (HPR) system, preparation of necessary safety documents and eventually obtaining an Operational Readiness Clearance (ORC). Figure 1 illustrates the various components of the development process. In the past, the north cave test station at A0 has supported the cold testing 3.9 GHz nine cell and single cell cavities, thus some of the components were available for use and some needed modification. The test dewar had the capacity to accommodate 1.3 GHz single cells although a new vertical insert that could handle both cavity types (1.3 and 3.9 GHz) had to be designed. The existing cryogenic system with an average capacity of {approx} 0.5 g/sec was deemed sufficient. The RF system was updated with broadband components and an additional amplifier with higher power capacity to handle higher gradients usually achieved in 1.3 GHz cavities. The initial testing phase was arbitrated to proceed with fixed power coupling. A new temperature mapping system was developed to provide the diagnostic tool for hot spot studies, quench characterization and field emission studies. The defining feature of this system was the use of diode sensors instead of the traditional carbon resistors as sensing elements. The unidirectional current carrying capacity (forward bias) of the diodes provided for the ease of multiplexing of the system, thus substantially reducing the number of cables required to power the sensors. The high gradient capacity of the 1.3 GHz cavities required a revision of the radiation shielding and interlocks. The cave was updated as per the recommendations of the radiation safety committee. The high pressure rinse system was updated with new adapters to assist the rinsing 1.3 GHz single cell cavities. Finally, a proposal for cold testing 1.3 GHz single cell cavities at A0 north cave was made to the small experiments approval committee, radiation safety committee and the Tevatron cryogenic safety sub-committee for an operational readiness clearance and the same was approved. The project was classified under research and development of single cell cavities (project 18) and was allocated a budget of $200,000 in FY 2007. 4. Single-dose Intravenous Toxicology Testing of Daebohwalryeok Pharmcopuncture in Sprague-Dawley Rats PubMed Central Sun, Seung-Ho; Park, Sunju; Jeong, Jong-Jin; Lee, Kwang-Ho; Yu, Jun-Sang; Seo, Hyung-Sik; Kwon, Ki-Rok 2015-01-01 Objectives: The aims of the study were to test the single-dose intravenous toxicity of Daebohwalryeok pharmacopuncture (DHRP) in Sprague-Dawley (SD) rats and to estimate the crude lethal dose. Methods: The experiments were conducted at Biotoxtech Co., a Good Laboratory Practice (GLP) laboratory, according to the GLP regulation and were approved by the Institutional Animal Care and Use Committee of Biotoxtech Co. (Approval no: 110156). The rats were divided into three groups: DHRP was injected into the rats in the two test groups at doses of 10 mL/kg and 20 mL/kg, respectively, and normal saline solution was injected into the rats in the control group. Single doses of DHRP were injected intravenously into 6 week old SD rats (5 male and 5 female rats per group). General symptoms were observed and weights were measured during the 14 day observation period after the injection. After the observation period, necropsies were done. Then, histopathological tests were performed. Weight data were analyzed with a one-way analysis of variance (ANOVA) by using statistical analysis system (SAS, version 9.2). Results: No deaths and no statistical significant weight changes were observed for either male or female SD rats in either the control or the test groups during the observation period. In addition, no treatment related general symptoms or necropsy abnormalities were observed. Histopathological results showed no DHRP related effects in the 20 mL/kg DHRP group for either male or female rats. Conclusion: Under the conditions of this study, the results from single-dose intravenous injections of DHRP showed that estimated lethal doses for both male and female rats were above 20 mL/kg. PMID:26120487 5. Single-neuron axonal pathfinding under geometric guidance: low-dose-methylmercury developmental neurotoxicity test. PubMed Wei, Lina; Sweeney, Andrew J; Sheng, Liyuan; Fang, Yu; Kindy, Mark S; Xi, Tingfei; Gao, Bruce Z 2014-09-21 Because the nervous system is most vulnerable to toxicants during development, there is a crucial need for a highly sensitive developmental-neurotoxicity-test model to detect potential toxicants at low doses. We developed a lab-on-chip wherein single-neuron axonal pathfinding under geometric guidance was created using soft lithography and laser cell-micropatterning techniques. After coating the surface with L1, an axon-specific member of the Ig family of cell adhesion molecules (CAMs), and optimizing microunit geometric parameters, we introduced low-dose methylmercury, a well-known, environmentally significant neurotoxicant, in the shared medium. Its developmental neurotoxicity was evaluated using a novel axonal pathfinding assay including axonal turning and branching rates at turning points in this model. Compared to the conventional neurite-outgrowth assay, this model's detection threshold for low-dose methylmercury was 10-fold more sensitive at comparable exposure durations. These preliminary results support study of developmental effects of known and potential neurotoxicants on axon pathfinding. This novel assay model would be useful to study neuronal disease mechanisms at the single-cell level. To our knowledge, the potential of methylmercury chloride to cause acute in vitro developmental neurotoxicity (DNT) at such a low dosage has not been reported. This is the first DNT test model with high reproducibility to use single-neuron axonal pathfinding under precise geometric guidance. PMID:25041816 6. Fluid Structure Interaction in a Cold Flow Test and Transient CFD Analysis of Out-of-Round Nozzles NASA Technical Reports Server (NTRS) Ruf, Joseph; Brown, Andrew; McDaniels, David; Wang, Ten-See 2010-01-01 This viewgraph presentation describes two nozzle fluid flow interactions. They include: 1) Cold flow nozzle tests with fluid-structure interaction at nozzle separated flow; and 2) CFD analysis for nozzle flow and side loads of nozzle extensions with various out-of-round cases. 7. Testing the efficiency of dsRNAi constructs in vivo : A transient expression assay based on two fluorescent proteins Microsoft Academic Search Ralph Panstruga; Min Chul Kim; Moo Je Cho; Paul Schulze-Lefert 2003-01-01 Double-stranded RNA interference technology has recently been shown to be a powerful tool to silence gene expression in various organisms, including plants. Sustained double-stranded RNA interference mediated gene silencing is normally triggered by hairpin RNAs generated by in vivo transcription of inverted repeat DNA constructs. To test the efficiency of inverted repeat constructs for their in vivo gene silencing capability, 8. A comparison of single-cycle versus multiple-cycle proof testing strategies NASA Technical Reports Server (NTRS) Hudak, S. J., Jr.; Mcclung, R. C.; Bartlett, M. L.; Fitzgerald, J. H.; Russell, D. A. 1990-01-01 An evaluation of single-cycle and multiple-cycle proof testing (MCPT) strategies for SSME components is described. Data for initial sizes and shapes of actual SSME hardware defects are analyzed statistically. Closed-form estimates of the J-integral for surface flaws are derived with a modified reference stress method. The results of load- and displacement-controlled stable crack growth tests on thin IN-718 plates with deep surface flaws are summarized. A J-resistance curve for the surface-cracked configuration is developed and compared with data from thick compact tension specimens. The potential for further crack growth during large unload/reload cycles is discussed, highlighting conflicting data in the literature. A simple model for ductile crack growth during MCPT based on the J-resistance curve is used to study the potential effects of key variables. The projected changes in the crack size distribution during MCPT depend on the interactions between several key parameters, including the number of proof cycles, the nature of the resistance curve, the initial crack size distribution, the component boundary conditions (load vs. displacement control), and the magnitude of the applied load or displacement. The relative advantages of single-cycle and multiple-cycle proof testing appear to be specific, therefore, to individual component geometry, material, and loading. 9. Negligible shift of 3Ag- potential in longer-chain carotenoids as revealed by a single persistent peak of 3Ag-?1Ag- stimulated emission followed by 3Ag-?1Ag- transient-absorption NASA Astrophysics Data System (ADS) Li, Chunyong; Miki, Takeshi; Kakitani, Yoshinori; Koyama, Yasushi; Nagae, Hiroyoshi 2007-12-01 Upon excitation of lycopene, anhydrorhodovibrin or spirilloxanthin to the 1Bu+(0) state, stimulated emission followed by transient-absorption was observed as a single peak with the 3Ag-(0) energy that had been determined by measurement of resonance-Raman excitation profiles. This observation was explained in terms of negligible shift of the 3Ag- potential, in reference to the 1Ag- potential, where only the 3Ag-(?)?1Ag-(?) emission and the 3Ag-(?)?1Ag-(?) absorption become allowed during the vibrational relaxation of ? = 2 ? 1 ? 0, starting from the 3Ag-(2) level generated by diabatic internal conversion from the 1Bu+(0) level, in anhydrorhodovibrin, for example. 10. Noise Impact Analysis:Noise Impact Analysis: Evaluating Transient Error Effects inEvaluating Transient Error Effects in E-print Network Dey, Sujit Noise Impact Analysis:Noise Impact Analysis: Evaluating Transient Error Effects inSevere reliability degradation due to many factors Transient noise: SingleTransient noise: Single effectpersistent error effect One possible remedy: robustness insertionOne possible remedy: robustness insertion 11. Testing for Renewal and Detailed Balance Violations in Single-Molecule Blinking Processes James B. Witkoskie and Jianshu Cao* E-print Network Cao, Jianshu Testing for Renewal and Detailed Balance Violations in Single-Molecule Blinking Processes James B, Massachusetts 02139 ReceiVed: March 9, 2006; In Final Form: July 28, 2006 This paper examines methods to test balance violations, and experimental condition dependences. The tests are simple to implement and allow 12. A Comparison of Three IRT Approaches to Examinee Ability Change Modeling in a Single-Group Anchor Test Design ERIC Educational Resources Information Center Paek, Insu; Park, Hyun-Jeong; Cai, Li; Chi, Eunlim 2014-01-01 Typically a longitudinal growth modeling based on item response theory (IRT) requires repeated measures data from a single group with the same test design. If operational or item exposure problems are present, the same test may not be employed to collect data for longitudinal analyses and tests at multiple time points are constructed with unique 13. Design and cold-air test of single-stage uncooled turbine with high work output NASA Technical Reports Server (NTRS) Moffitt, T. P.; Szanca, E. M.; Whitney, W. J.; Behning, F. P. 1980-01-01 A solid version of a 50.8 cm single stage core turbine designed for high temperature was tested in cold air over a range of speed and pressure ratio. Design equivalent specific work was 76.84 J/g at an engine turbine tip speed of 579.1 m/sec. At design speed and pressure ratio, the total efficiency of the turbine was 88.6 percent, which is 0.6 point lower than the design value of 89.2 percent. The corresponding mass flow was 4.0 percent greater than design. 14. Fracture energy for three-point-bend tests on single-edge-notched beams Microsoft Academic Search L. J. Malvar; G. E. Warren 1988-01-01 Three test series of single-edge-notched beams in three-point bending are conducted to evaluate the fracture energy of concrete.\\u000a The fracture energy is determined from the area under the complete load: load-point deflection diagram. The nonlinear fictitious\\u000a crack model is implemented in a finite-element analysis showing good agreement with the experimental data.\\u000a \\u000a By varying the notch depth and the beam depth 15. RELAP5/MOD3 Analysis of Transient Steam-Generator Behavior During Turbine Trip Test of a Prototype Fast Breeder Reactor MONJU SciTech Connect Yoshihisa Shindo; Hiroshi Endo; Tomoko Ishizu; Kazuo Haga [Japan Nuclear Energy Safety Organization (Japan) 2006-07-01 In order to develop a thermal-hydraulic model of the steam-generator (SG) to simulate transient phenomena in the sodium cooled fast breeder reactor (FBR) MONJU, Japan Nuclear Energy Safety Organization (JNES) verified the SG model using the RELAP5/MOD3 code against the results of the turbine trip test at a 40% power load of MONJU. The modeling by using RELAP5 was considered to explain the significant observed behaviors of the pressure and the temperature of the EV steam outlet, and the temperature of water supply distributing piping till 600 seconds after the turbine trip. The analysis results of these behaviors showed good agreement with the test results based on results of parameter study as the blow efficiency (release coef.) and heat transferred from the helical coil region to the down-comer (temperature heating down-comer tubes). It was found that the RELAP5/MOD3 code with a two-fluids model can predict well the physical situation: the gas-phase of steam generated by the decompression boiling moves upward in the down-comer tubes accompanied by the enthalpy increase of the water supply chambers; and that the pressure change of a 'shoulder' like shape is induced by the mass balance between the steam mass generated in the down-comer tubes and the steam mass blown from the SG. The applicability of RELAP5/MOD3 to SG modeling was confirmed by simulating the actual FBR system. (authors) 16. Temperature in a J47-25 Turbojet-engine Combustor and Turbine Sections During Steady-state and Transient Operation in a Sea-level Test Stand NASA Technical Reports Server (NTRS) Morse, C R; Johnston, J R 1955-01-01 In order to determine the conditions of engine operation causing the most severe thermal stresses in the hot parts of a turbojet engine, a J47-25 engine was instrumented with thermocouples and operated to obtain engine material temperatures under steady-state and transient conditions. Temperatures measured during rated take-off conditions of nozzle guide vanes downstream of a single combustor differed on the order of 400 degrees F depending on the relation of the blades position to the highest temperature zone of the burner. Under the same operation conditions, measured midspan temperatures in a nozzle guide vane in the highest temperature zone of a combustor wake ranged from approximately 1670 degrees F at leading and trailing edges to 1340 degrees F at midchord on the convex side of the blade. The maximum measured nozzle-guide-vane temperature of 1920degrees at the trailing edge occurred during a rapid acceleration from idle to rated take-off speed following which the tail-pipe gas temperature exceeded maximum allowable temperature by 125 degrees F. 17. Evaluation of testing strategies to identify infected animals at a single round of testing within dairy herds known to be infected with Mycobacterium avium ssp. paratuberculosis. PubMed More, S J; Cameron, A R; Strain, S; Cashman, W; Ezanno, P; Kenny, K; Fourichon, C; Graham, D 2015-08-01 As part of a broader control strategy within herds known to be infected with Mycobacterium avium ssp. paratuberculosis (MAP), individual animal testing is generally conducted to identify infected animals for action, usually culling. Opportunities are now available to quantitatively compare different testing strategies (combinations of tests) in known infected herds. This study evaluates the effectiveness, cost, and cost-effectiveness of different testing strategies to identify infected animals at a single round of testing within dairy herds known to be MAP infected. A model was developed, taking account of both within-herd infection dynamics and test performance, to simulate the use of different tests at a single round of testing in a known infected herd. Model inputs included the number of animals at different stages of infection, the sensitivity and specificity of each test, and the costs of testing and culling. Testing strategies included either milk or serum ELISA alone or with fecal culture in series. Model outputs included effectiveness (detection fraction, the proportion of truly infected animals in the herd that are successfully detected by the testing strategy), cost, and cost-effectiveness (testing cost per true positive detected, total cost per true positive detected). Several assumptions were made: MAP was introduced with a single animal and no management interventions were implemented to limit within-herd transmission of MAP before this test. In medium herds, between 7 and 26% of infected animals are detected at a single round of testing, the former using the milk ELISA and fecal culture in series 5 yr after MAP introduction and the latter using fecal culture alone 15 yr after MAP introduction. The combined costs of testing and culling at a single round of testing increases with time since introduction of MAP infection, with culling costs being much greater than testing costs. The cost-effectiveness of testing varied by testing strategy. It was also greater at 5 yr, compared with 10 or 15 yr, since MAP introduction, highlighting the importance of early detection. Future work is needed to evaluate these testing strategies in subsequent rounds of testing as well as accounting for different herd dynamics and different levels of herd biocontainment. PMID:26074225 18. Gravitational independence of single-breath washout tests in recumbent dogs NASA Technical Reports Server (NTRS) Tomioka, Shinichi; Kubo, Susumu; Guy, Harold J. B.; Prisk, G. K. 1988-01-01 The effect of gravitational orientation in the mechanism of lung filling and emptying in dogs was examined by conducting simultaneously Ar-bolus and N2 single-breath washout tests (SBWTs) in 10 anesthetized dogs (prone and supine), with three of the dogs subjected to body rotation. Transpulmonary pressure was measured simultaneously, allowing identification of the lung volume above residual volume at which there was an inflection point in the pressure-volume curve. Combined resident gas and bolus SBWTs in recumbent dogs were found to be different from such tests in humans; in dogs, the regional distribution of ventilation was not primarily determined by gravity. The measurements did not make it possible to discern exact mechanisms of filling and emptying, but both processes appear to be related to lung, thorax, and mediastinum interactions and/or differences in regional mechanical properties of the lungs. 19. Loop Identification and Capacity Estimation of Digital Subscriber Lines with Single Ended Line Testing NASA Astrophysics Data System (ADS) Neus, Carine; Foubert, Wim; van Biesen, Leo Digital subscriber lines offer the possibility to deliver broadband services over the existing telephone network. Still, beforehand subscriber loops must be tested to see whether they can support high-speed data services, and at what bit rate. From the existing measurement techniques, Single Ended Line Testing is often preferred because all necessary measurements can be performed from the central office. Consequently the capacity cannot be measured directly, but should be calculated through the estimation of the loop make-up. This paper discusses some main difficulties of this identification. Moreover, in contrast to the traditional approach where the data are interpreted in the time domain, this paper presents a new approach by doing most of the processing in the frequency domain. 20. Single subject fMRI test-retest reliability metrics and confounding factors. PubMed Gorgolewski, Krzysztof J; Storkey, Amos J; Bastin, Mark E; Whittle, Ian; Pernet, Cyril 2013-04-01 While the fMRI test-retest reliability has been mainly investigated from the point of view of group level studies, here we present analyses and results for single-subject test-retest reliability. One important aspect of group level reliability is that not only does it depend on between-session variance (test-retest), but also on between-subject variance. This has partly led to a debate regarding which reliability metric to use and how different sources of noise contribute to between-session variance. Focusing on single subject reliability allows considering between-session only. In this study, we measured test-retest reliability in four behavioural tasks (motor mapping, covert verb generation, overt word repetition, and a landmark identification task) to ensure generalisation of the results and at three levels of data processing (time-series correlation, t value variance, and overlap of thresholded maps) to understand how each step influences the other and how confounding factors influence reliability at each of these steps. The contributions of confounding factors (scanner noise, subject motion, and coregistration) were investigated using multiple regression and relative importance analyses at each step. Finally, to achieve a fuller picture of what constitutes a reliable task, we introduced a bootstrap technique of within- vs. between-subject variance. Our results show that (i) scanner noise and coregistration errors have little contribution to between-session variance (ii) subject motion (especially correlated with the stimuli) can have detrimental effects on reliability (iii) different tasks lead to different reliability results. This suggests that between-session variance in fMRI is mostly caused by the variability of underlying cognitive processes and motion correlated with the stimuli rather than technical limitations of data processing. PMID:23153967 1. Definition of Capabilities Needed for a Single Event Effects Test Facility SciTech Connect Riemer, Bernie [ORNL; Gallmeier, Franz X [ORNL 2014-12-01 EXECUTIVE SUMMARY The Federal Aviation Administration (FAA) is contemplating new regulations mandating testing of the vulnerability of flight-critical avionics to single event effects (SEE). A limited number of high-energy neutron test facilities currently serve the SEE industrial and institutional research community. The FAA recognizes that existing facilities have insufficient test capacity to meet new demand from such mandates; it desires more flexible irradiation capabilities to test complete, large systems and would like capabilities to address greater concerns for thermal neutrons. For this reason, the FAA funded this study by Spallation Neutron Source (SNS) staff with the ultimate aim of developing options for SEE test facilities using high-energy neutrons at the SNS complex. After an investigation of current SEE test practices and assessment of future testing requirements, three concepts were identified covering a range of test functionality, neutron flux levels, and fidelity to the atmospheric neutron spectrum. The costs and times required to complete each facility were also estimated. SEE testing is generally performed by accelerating the event rate to a point where the effects are still dominated by single events and double event causes of failures are negligible. In practice, acceleration factors of as high as 106 are applicable for component testing, whereas for systems testing acceleration factors of 104 seem to be the upper limit. It is strongly desirable that the irradiation facility be tunable over a large range of high-energy neutron fluxes of 102 104 n/cm2/s for systems testing and from 104 107 n/cm2/s for components testing. The most capable, most flexible, and highest-test-capacity option is a new stand-alone target station named the High-Energy neutron Test Station (HETS). It is also the most expensive option, with a cost to complete of approximately$100 million. Dual test enclosures would allow for simultaneous testing activity effectively doubling overall test capacity per HETS operating hour. Using about 1 kilowatt (kW) of proton power extracted from the accelerator before injection in the accumulator ring, its operation would be unnoticeable by neutron scattering users at the SNS target station. The H beam laser stripping technique would allow for control of beam power on the HETS target independent from power delivered to the SNS. Large systems with frontal areas of up to 1 2 m2 could be accommodated with integral high-energy flux values (above 10 megaelectron-volt, or MeV) to at most 104 n/cm2/s; components could also be tested with flux levels to at most 107 n/cm2/s on beam sizes of up to 0.2 0.2 m2. Selectable moderating material and neutron filters would allow tailoring of the neutron spectrum to user demands; charged particle deflectors could be switched to allow or deflect protons, pions, and muons. It is estimated that HETS would take 5 years to complete after award of contract, including engineering design and construction. Commissioning would take at least another 6 months. Interference with SNS principal operations was not considered in the construction time estimate; connection of the proton transport line and tunnel from the accelerator high energy beam transport (HEBT) and construction around existing site utilities would require careful planning and coordination with beam operations at the SNS. A high-energy (HE) neutron test facility using an available beam line on the SNS target station is a technically and financially attractive option. Inspired by the new ChipIR instrument on the ISIS TS 2 spallation source in the UK, a similar facility could be placed on an unused beam line in the SNS instrument hall [e.g., on beam line 8 (both A and B channels would be needed) or on beam line 10]. The performance would approach that of an HETS (~80%), but it would be operationally more limited, with only a single user at a time. Space is more limited, so the maximum system size would be about half of that in an HETS. Flexibility to tailor the spectrum would be somewhat more limited. While t
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E-print Network
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3. Decision trees for real-time transient stability prediction
SciTech Connect
Rovnyak, S.; Thorp, J. (Cornell Univ., Ithaca, NY (United States)); Kretsinger, S.; Brown, D. (Univ. of Virginia, Charlottesville, VA (United States))
1994-08-01
The ability to rapidly acquire synchronized phasor measurements from around the system opens up new possibilities for power system protection and control. This paper demonstrates how decision trees can be constructed off-line and then utilized on-line for predicting transient stability in real-time. Primary features of the method include building a single tree for all fault locations, using a short window of realistic-precision post-fault phasor, measurements for the prediction, and testing robustness to variations in the operating point. Several candidate decision trees are tested on 40,800 faults from 50 randomly generated operating points on the New England 39 bus test system.
4. Summary of Group Development and Testing for Single Shell Tank Closure at Hanford
SciTech Connect
Harbour, John, R.
2005-04-28
This report is a summary of the bench-scale and large scale experimental studies performed by Savannah River National Laboratory for CH2M HILL to develop grout design mixes for possible use in producing fill materials as a part of Tank Closure of the Single-Shell Tanks at Hanford. The grout development data provided in this report demonstrates that these design mixes will produce fill materials that are ready for use in Hanford single shell tank closure. The purpose of this report is to assess the ability of the proposed grout specifications to meet the current requirements for successful single shell tank closure which will include the contracting of services for construction and operation of a grout batch plant. The research and field experience gained by SRNL in the closure of Tanks 17F and 20F at the Savannah River Site was leveraged into the grout development efforts for Hanford. It is concluded that the three Hanford grout design mixes provide fill materials that meet the current requirements for successful placement. This conclusion is based on the completion of recommended testing using Hanford area materials by the operators of the grout batch plant. This report summarizes the regulatory drivers and the requirements for grout mixes as tank fill material. It is these requirements for both fresh and cured grout properties that drove the development of the grout formulations for the stabilization, structural and capping layers.
5. Stress transfer in microdroplet tensile test: PVC-coated and uncoated Kevlar-29 single fiber
NASA Astrophysics Data System (ADS)
Zhenkun, Lei; Quan, Wang; Yilan, Kang; Wei, Qiu; Xuemin, Pan
2010-11-01
The single fiber/microdroplet tensile test is applied for evaluating the interfacial mechanics between a fiber and a resin substrate. It is used to investigate the influence of a polymer coating on a Kevlar-29 fiber surface, specifically the stress transfer between the fiber and epoxy resin in a microdroplet. Unlike usual tests, this new test ensures a symmetrical axial stress on the embedded fiber and reduces the stress singularity that appears at the embedded fiber entry. Using a homemade loading device, symmetrical tensile tests are performed on a Kevlar-29 fiber with or without polyvinylchloride (PVC) coating, the surface of which is in contact with two epoxy resin microdroplets during curing. Raman spectra on the embedded fiber are recorded by micro-Raman Spectroscopy under different strain levels. Then they are transformed to the distributions of fiber axis stress based on the relationship between stress and Raman shift. The Raman results reveal that the fiber axial stresses increase with the applied loads, and the antisymmetric interfacial shear stresses, obtained by a straightforward balance of shear-to-axial forces argument, lead to the appearance of shear stress concentrations at a distance to the embedded fiber entry. The load is transferred from the outer fiber to the embedded fiber in the epoxy microdroplet. As is observed by scanning electronic microscopy (SEM), the existence of a flexible polymer coating on the fiber surface reduces the stress transfer efficiency.
6. Fractal analysis of pressure transients in the Geysers Geothermal Field
SciTech Connect
Acuna, J.A.; Ershaghi, I.; Yortsos, Y.C.
1992-01-01
The conventionally accepted models for the interpretation of pressure transient tests in naturally fractured reservoirs usually involve simplistic assumptions regarding the geometry and transport properties of the fractured medium. Many single well tests in this type of reservoirs fail to show the predicted behavior for dual or triple porosity or permeability systems and cannot be explained by these models. This paper describes the application of a new model based on a fractal interpretation of the fractured medium. The approach, discussed elsewhere [2], [6], is applied to field data from The Geysers Geothermal Field. The objective is to present an alternative interpretation to well tests that characterizes the fractured medium in a manner more consistent with other field evidence. The novel insight gained from fractal geometry allows the identification of important characteristics of the fracture structure that feeds a particular well. Some simple models are also presented that match the field transient results.
7. The Radio Transient Sky
NASA Astrophysics Data System (ADS)
Lazio, J.
Radio transients are known on time scales from nanoseconds to years, from sources in the Galaxy and beyond, and with either coherent or incoherent emission mechanisms. Observations of this wide variety of sources are relevant to many of the highest profile questions in astronomy and astrophysics. As illustrations of the breadth of the radio transient sky, both coherent and incoherent radio emission has long been known from stars and stellar remnants and has informed topics ranging from stellar evolution to Galactic structure to relativistic jet dynamics to tests of fundamental physics. Coherent radio emission is now also known from brown dwarfs, and there are active programs to find similar emissions from extrasolar planets. Outside of the Galaxy, incoherent radio counterparts to supernovae, tidal disruption events, and gamma-ray bursts is well known and have contributed to topics such as understanding the cosmic star formation rate and the formation of relativistic jets. Excitingly, coherent radio bursts that appear to be at cosmological distances were recently discovered. I provide a survey of the radio transient sky, illustrating both how radio transients are part of the Hot-Wired Sky and are likely to help drive the Hot-Wiring. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
8. SEU and Test Considerations for FPGA Devices
NASA Technical Reports Server (NTRS)
Berg, Malanie
2006-01-01
This viewgraph presentation provides an overview of Field Programmable Gate Arrays (FPGAs), what they are, implementations in space missions, and current available technologies. Single Event Upsets (SEUs) and Single Event Transients (SETs) are discussed in relation to their effects on FPGAs. Testing goals, considerations, and data analysis are reviewed.
9. Compendium of Single-Event Latchup and Total Ionizing Dose Test Results of Commercial Analog to Digital Converters
NASA Technical Reports Server (NTRS)
Irom, Farokh; Agarwal, Shri G.
2012-01-01
This paper reports single-event latchup and total dose results for a variety of analog to digital converters targeted for possible use in NASA spacecraft's. The compendium covers devices tested over the last 15 years.
10. Platelet function testing in transient ischaemic attack and ischaemic stroke: A comprehensive systematic review of the literature.
PubMed
Lim, Soon Tjin; Coughlan, Catherine A; Murphy, Stephen J X; Fernandez-Cadenas, Israel; Montaner, Joan; Thijs, Vincent; Marquardt, Lars; McCabe, Dominick J H
2015-01-01
The majority of patients with ischaemic cerebrovascular disease (CVD) are not protected from further vascular events with antiplatelet therapy. Measurement of inhibition of platelet function ex vivo on antiplatelet therapy, using laboratory tests that correlate with the clinical effectiveness of these agents, would potentially enable physicians to tailor antiplatelet therapy to suit individuals. A systematic review of the literature was performed to collate all available data on ex vivo platelet function/reactivity in CVD patients, especially those treated with aspirin, dipyridamole or clopidogrel. Particular emphasis was paid to information from commonly available whole blood platelet function analysers (PFA-100, VerifyNow and Multiplate). Data on pharmacogenetic mechanisms potentially influencing high on-treatment platelet reactivity (HTPR) on antiplatelet therapy in CVD were reviewed. Two-hundred forty-nine potentially relevant articles were identified; 93 manuscripts met criteria for inclusion. The prevalence of ex vivo HTPR in CVD varies between 3-62% with aspirin monotherapy, 8-61% with clopidogrel monotherapy and 56-59% when dipyridamole is added to aspirin in the early, subacute or late phases after TIA/stroke onset. The prevalence of HTPR on aspirin was higher on the PFA-100 than on the VerifyNow in one study (p?testing platforms, in conjunction with pharmacogenetic data, improves our ability to predict the risk of recurrent vascular events in CVD patients, and thus enhance secondary prevention following TIA or ischaemic stroke. PMID:26042726
11. Single-Crystal NiAl-X Alloys Tested for Hot Corrosion
NASA Technical Reports Server (NTRS)
Nesbitt, James A.
1999-01-01
Single-crystal nickel aluminide (NiAl) has been investigated extensively throughout the last several years as a potential structural material in aero-gas turbine engines. The attractive features of NiAl in comparison to Ni-base superalloys include a higher melting point, lower density, higher thermal conductivity, and excellent oxidation resistance. However, NiAl suffers from a lack of ductility and fracture toughness at low temperatures and a low creep strength at high temperatures. Alloying additions of hafnium (Hf), gallium (Ga), titanium (Ti), and chromium (Cr) have each shown some benefit to the mechanical properties over that of the binary alloy. However, the collective effect of these alloying additions on the environmental resistance of NiAl-X was unclear. Hence, the present study was undertaken to examine the hot corrosion behavior of these alloys. A companion study examined the cyclic oxidation resistance of these alloys. Several single-crystal NiAl-X alloys (where X is Hf, Ti, Cr, or Ga) underwent hot corrosion testing in a Mach 0.3 burner rig at the NASA Lewis Research Center. Samples were tested for up to 300 1-hr cycles at a temperature of 900 C. It was found that increasing the Ti content from 1 to 5 at.% degraded the hot corrosion behavior. This decline in the behavior was reflected in high weight gains and large corrosion mound formation during testing (see the figures). However, the addition of 1 to 2 at.% Cr to alloys containing 4 to 5 at.% Ti appeared to greatly reduce the susceptibility of these alloys to hot corrosion attack and negated the deleterious effect of the increased Ti addition.
12. Additive Manufacturing Thermal Performance Testing of Single Channel GRCop-84 SLM Components
NASA Technical Reports Server (NTRS)
Garcia, Chance P.; Cross, Matthew
2014-01-01
The surface finish found on components manufactured by sinter laser manufacturing (SLM) is rougher (0.013 - 0.0006 inches) than parts made using traditional fabrication methods. Internal features and passages built into SLM components do not readily allow for roughness reduction processes. Alternatively, engineering literature suggests that the roughness of a surface can enhance thermal performance within a pressure drop regime. To further investigate the thermal performance of SLM fabricated pieces, several GRCop-84 SLM single channel components were tested using a thermal conduction rig at MSFC. A 20 kW power source running at 25% duty cycle and 25% power level applied heat to each component while varying water flow rates between 2.1 - 6.2 gallons/min (GPM) at a supply pressure of 550 to 700 psi. Each test was allowed to reach quasi-steady state conditions where pressure, temperature, and thermal imaging data were recorded. Presented in this work are the heat transfer responses compared to a traditional machined OHFC Copper test section. An analytical thermal model was constructed to anchor theoretical models with the empirical data.
13. Crash tests of four identical high-wing single-engine airplanes
NASA Technical Reports Server (NTRS)
Vaughan, V. L., Jr.; Hayduk, R. J.
1980-01-01
Four identical four place, high wing, single engine airplane specimens with nominal masses of 1043 kg were crash tested at the Langley Impact Dynamics Research Facility under controlled free flight conditions. These tests were conducted with nominal velocities of 25 m/sec along the flight path angles, ground contact pitch angles, and roll angles. Three of the airplane specimens were crashed on a concrete surface; one was crashed on soil. Crash tests revealed that on a hard landing, the main landing gear absorbed about twice the energy for which the gear was designed but sprang back, tending to tip the airplane up to its nose. On concrete surfaces, the airplane impacted and remained in the impact attitude. On soil, the airplane flipped over on its back. The crash impact on the nose of the airplane, whether on soil or concrete, caused massive structural crushing of the forward fuselage. The liveable volume was maintained in both the hard landing and the nose down specimens but was not maintained in the roll impact and nose down on soil specimens.
14. Preliminary Test Results from 650 MHz Single Cell Medium Beta Cavities for Project X
SciTech Connect
Marhauser, Frank; Kneisel, Peter; Burrill, Andrew; Kushnick, Peter; Rimmer, R. A.
2011-07-01
We have fabricated two single cell 650 MHz {beta}=0.61 cavities of a JLab design, which possibly can be used for the proposed Project X proton linac application. Both cavities were manufactured at JLab from RRR>250 niobium sheet of 4 mm thickness using standard techniques such as deep drawing, electron beam welding, buffered chemical polishing, hydrogen degassing heat treatment, high pressure ultrapure water rinsing and clean room assembly. Initially cavity no. 1 was -- after final surface treatment by buffered chemical polishing (BCP) -- measured without any provisions for stiffening. As expected, the pressure sensitivity and the Lorentz Force detuning coefficients were relatively high; however, the RF performance was very encouraging: the cavity exhibited a Q-value > 10{sup 11} at 1.6K, corresponding to a residual resistance of < 1.5 n{Omega} The initial gradient was limited to E{sub acc} ~ 18 MV/m, limited by field emission. In a subsequent test, the cavity was re-rinsed and stiffened up, resulting in a somewhat improved mechanical behavior, but no improvement in rf performance. The second cavity was also tested twice, before and after low temperature baking. The results from all tests are reported in this contribution.
15. A Comparison of Single-Cycle Versus Multiple-Cycle Proof Testing Strategies
NASA Technical Reports Server (NTRS)
McClung, R. C.; Chell, G. G.; Millwater, H. R.; Russell, D. A.; Orient, G. E.
1996-01-01
Single-cycle and multiple-cycle proof testing (SCPT and MCPT) strategies for reusable aerospace propulsion system components are critically evaluated and compared from a rigorous elastic-plastic fracture mechanics perspective. Earlier MCPT studies are briefly reviewed. New J-integral estimation methods for semi-elliptical surface cracks and cracks at notches are derived and validated. Engineering methods are developed to characterize crack growth rates during elastic-plastic fatigue crack growth (FCG) and the tear-fatigue interaction near instability. Surface crack growth experiments are conducted with Inconel 718 to characterize tearing resistance, FCG under small-scale yielding and elastic-plastic conditions, and crack growth during simulated MCPT. Fractography and acoustic emission studies provide additional insight. The relative merits of SCPT and MCPT are directly compared using a probabilistic analysis linked with an elastic-plastic crack growth computer code. The conditional probability of failure in service is computed for a population of components that have survived a previous proof test, based on an assumed distribution of initial crack depths. Parameter studies investigate the influence of proof factor, tearing resistance, crack shape, initial crack depth distribution, and notches on the MCPT vs. SCPT comparison. The parameter studies provide a rational basis to formulate conclusions about the relative advantages and disadvantages of SCPT and MCPT. Practical engineering guidelines are proposed to help select the optimum proof test protocol in a given application.
16. A Comparison of Single-Cycle Versus Multiple-Cycle Proof Testing Strategies
NASA Technical Reports Server (NTRS)
McClung, R. C.; Chell, G. G.; Millwater, H. R.; Russell, D. A.; Millwater, H. R.
1999-01-01
Single-cycle and multiple-cycle proof testing (SCPT and MCPT) strategies for reusable aerospace propulsion system components are critically evaluated and compared from a rigorous elastic-plastic fracture mechanics perspective. Earlier MCPT studies are briefly reviewed. New J-integral estimation methods for semielliptical surface cracks and cracks at notches are derived and validated. Engineering methods are developed to characterize crack growth rates during elastic-plastic fatigue crack growth (FCG) and the tear-fatigue interaction near instability. Surface crack growth experiments are conducted with Inconel 718 to characterize tearing resistance, FCG under small-scale yielding and elastic-plastic conditions, and crack growth during simulated MCPT. Fractography and acoustic emission studies provide additional insight. The relative merits of SCPT and MCPT are directly compared using a probabilistic analysis linked with an elastic-plastic crack growth computer code. The conditional probability of failure in service is computed for a population of components that have survived a previous proof test, based on an assumed distribution of initial crack depths. Parameter studies investigate the influence of proof factor, tearing resistance, crack shape, initial crack depth distribution, and notches on the MCPT versus SCPT comparison. The parameter studies provide a rational basis to formulate conclusions about the relative advantages and disadvantages of SCPT and MCPT. Practical engineering guidelines are proposed to help select the optimum proof test protocol in a given application.
17. A single sample GnRHa stimulation test in the diagnosis of precocious puberty
PubMed Central
2012-01-01
Context Gonadotropin-releasing hormone (GnRH) has been the standard test for diagnosing central precocious puberty. Because GnRH is no longer available, GnRH analogues (GnRHa) are now used. Random LH concentration, measured by the third-generation immunochemiluminometric assay, is a useful screening tool for central precocious puberty. However, GnRHa stimulation test should be considered, when a basal LH measurement is inconclusive. However optimal sampling times for luteinizing hormone (LH) have yet to be established. Purpose To determine the appropriate sampling time for LH post leuprolide challenge. Methods A retrospective analysis of multi-sample GnRHa stimulation tests performed in 155 children (aged 19?years) referred for precocious puberty to Texas Childrens Hospital. After 20 mcg/kg of SQ leuprolide acetate, samples were obtained at 0, 1, 3, and 6 hours. Results Of 71 children with clinical evidence of central precocious puberty, fifty nine children had a peak LH >5 mIU/mL. 52 (88%) of these responders had positive responses at 1 hour (95% CI is 8096%), whereas all 59 children (100%) had a peak LH response >5 mIU/mL at 3 hours (95% CI is 94-100%), P?=?0.005. Conclusions A single serum LH sample collected 3 hours post GnRHa challenge is the optimal sample to establish the diagnosis of central precocious puberty. PMID:22809285
18. Modeling Single Well Injection-Withdrawal (SWIW) Tests for Characterization of Complex Fracture-Matrix Systems
SciTech Connect
Cotte, F.P.; Doughty, C.; Birkholzer, J.
2010-11-01
The ability to reliably predict flow and transport in fractured porous rock is an essential condition for performance evaluation of geologic (underground) nuclear waste repositories. In this report, a suite of programs (TRIPOLY code) for calculating and analyzing flow and transport in two-dimensional fracture-matrix systems is used to model single-well injection-withdrawal (SWIW) tracer tests. The SWIW test, a tracer test using one well, is proposed as a useful means of collecting data for site characterization, as well as estimating parameters relevant to tracer diffusion and sorption. After some specific code adaptations, we numerically generated a complex fracture-matrix system for computation of steady-state flow and tracer advection and dispersion in the fracture network, along with solute exchange processes between the fractures and the porous matrix. We then conducted simulations for a hypothetical but workable SWIW test design and completed parameter sensitivity studies on three physical parameters of the rock matrix - namely porosity, diffusion coefficient, and retardation coefficient - in order to investigate their impact on the fracture-matrix solute exchange process. Hydraulic fracturing, or hydrofracking, is also modeled in this study, in two different ways: (1) by increasing the hydraulic aperture for flow in existing fractures and (2) by adding a new set of fractures to the field. The results of all these different tests are analyzed by studying the population of matrix blocks, the tracer spatial distribution, and the breakthrough curves (BTCs) obtained, while performing mass-balance checks and being careful to avoid some numerical mistakes that could occur. This study clearly demonstrates the importance of matrix effects in the solute transport process, with the sensitivity studies illustrating the increased importance of the matrix in providing a retardation mechanism for radionuclides as matrix porosity, diffusion coefficient, or retardation coefficient increase. Interestingly, model results before and after hydrofracking are insensitive to adding more fractures, while slightly more sensitive to aperture increase, making SWIW tests a possible means of discriminating between these two potential hydrofracking effects. Finally, we investigate the possibility of inferring relevant information regarding the fracture-matrix system physical parameters from the BTCs obtained during SWIW testing.
19. Frequency of coronal transients and solar activity
E. Hildner; J. T. Gosling; R. M. MacQueen; R. H. Munro; A. I. Poland; C. L. Ross
1976-01-01
The High Altitude Observatory's white light coronagraph aboard Skylab observed some 110 coronal transients - rapid changes in appearance of the corona - during its 227 days of operation. The longitudes of the origins of these transients were not distributed uniformly around the solar surface (51 of the 100 events observed in seven solar rotations arose from a single quadrant
20. Potentiometric, electronic, and transient absorptive spectroscopic properties of oxidized single-walled carbon nanotubes helically wrapped by ionic, semiconducting polymers in aqueous and organic media.
PubMed
Deria, Pravas; Olivier, Jean-Hubert; Park, Jaehong; Therien, Michael J
2014-10-01
We report the first direct cyclic voltammetric determination of the valence and conduction band energy levels for noncovalently modified (6,5) chirality enriched SWNTs [(6,5) SWNTs] in which an aryleneethynylene polymer monolayer helically wraps the nanotube surface at periodic and constant morphology. Potentiometric properties as well as the steady-state and transient absorption spectroscopic signatures of oxidized (6,5) SWNTs were probed as a function of the electronic structure of the aryleneethynylene polymer that helically wraps the nanotube surface, the solvent dielectric, and nanotube hole polaron concentration. These data: (i) highlight the utility of these polymer-SWNT superstructures in experiments that establish the potentiometric valence and conduction band energy levels of semiconducting carbon nanotubes; (ii) provide a direct measure of the (6,5) SWNT hole polaron delocalization length (2.75 nm); (iii) determine steady-state and transient electronic absorptive spectroscopic signatures that are uniquely associated with the (6,5) SWNT hole polaron state; and (iv) demonstrate that modulation of semiconducting polymer frontier orbital energy levels can drive spectral shifts of SWNT hole polaron transitions as well as regulate SWNT valence and conduction band energies. PMID:25211354
1. Analysis and testing of high entrainment single nozzle jet pumps with variable mixing tubes
NASA Technical Reports Server (NTRS)
Hickman, K. E.; Hill, P. G.; Gilbert, G. B.
1972-01-01
An analytical model was developed to predict the performance characteristics of axisymmetric single-nozzle jet pumps with variable area mixing tubes. The primary flow may be subsonic or supersonic. The computer program uses integral techniques to calculate the velocity profiles and the wall static pressures that result from the mixing of the supersonic primary jet and the subsonic secondary flow. An experimental program was conducted to measure mixing tube wall static pressure variations, velocity profiles, and temperature profiles in a variable area mixing tube with a supersonic primary jet. Static pressure variations were measured at four different secondary flow rates. These test results were used to evaluate the analytical model. The analytical results compared well to the experimental data. Therefore, the analysis is believed to be ready for use to relate jet pump performance characteristics to mixing tube design.
2. Effect of moisture on the interfacial shear strength: A study using the single fiber fragmentation test
SciTech Connect
Pratt, B.A.; Bradley, W.L. [Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering
1997-12-31
The effect of absorbed moisture on the interfacial strength of a carbon fiber/epoxy matrix composite has been studied using the single fiber fragmentation test. The absorption of 1.40% moisture produced a reduction less than 20% in the interfacial shear strength. This reduction in interfacial strength may be associated with a reduction in the residual compressive stresses at the fiber/matrix interface associated with the cooldown from the curing temperature, a weakening of the chemical adhesion, or a softening of the matrix giving failure by interphase yielding. These results suggest that long-term durability of carbon fiber/epoxy matrix composites in seawater may not be much affected by absorbed seawater.
3. Coherent single pion production by antineutrino charged current interactions and test of PCAC
NASA Astrophysics Data System (ADS)
Marage, P.; Aderholz, M.; Allport, P.; Armenise, N.; Baton, J. P.; Berggren, M.; Bertrand, D.; Brisson, V.; Bullock, F. W.; Burkot, W.; Calicchio, M.; Clayton, E. F.; Coghen, T.; Cooper-Sarkar, A. M.; Erriquez, O.; Fitch, P. J.; Gerbier, G.; Guy, J.; Hamisi, F.; Hulth, P. O.; Jones, G. T.; Kasper, P.; Klein, H.; Middleton, R. P.; Miller, D. B.; Mobayyen, M. M.; Morrison, D. R. O.; Natali, S.; Neveu, M.; O'Neale, S. W.; Parker, M. A.; Petiau, P.; Sacton, J.; Sansum, R. A.; Simopoulou, E.; Valle, C.; Varvell, K.; Vayaki, A.; Venus, W.; Wachsmuth, H.; Wells, J.; Wittek, W.
1986-06-01
The cross section for coherent production of a single ?- meson in charged current antineutrino interactions on neon nuclei has been measured in BEBC to be (17525) 10-40 cm2/neon nucleus, averaged over the energy spectrum of the antineutrino wide band beam at the CERN SPS; this corresponds to (0.90.1) % of the total charged currentbar v_? cross section. The distributions of kinematical variables are in agreement with theoretical predictions based on the PCAC hypothesis and the meson dominance model; in particular, the Q 2 dependence is well described by a propagator containing a mass m=(1.350.18) GeV. The absolute value of the cross section is also in agreement with the model. This analysis thus provides a test of the PCAC hypothesis in the antineutrino energy range 5 150 GeV.
4. Confirmation on the size-dependence of Young's modulus of single crystal silicon from the TEM tensile tests
Q. H. Jin; T. Li; Y. L. Wang; X. L. Gao; F. F. Xu
2010-01-01
With the developed process, four MEMS tensile testing chips of ;-oriented single crystal silicon (SCS) nanobeams were achieved in one SOI wafer with thickness from 45 to 100 nm. Mounting the chips onto a custom made TEM sample holder, which integrated also comb drives and force sensor beam, in-situ TEM tensile tests were carried out. The measured Young's modulus (from
5. Development and test of single-bore cos-ϑ Nb3Sn dipole models with cold iron yoke
N. Andreev; G. Ambrosio; E. Barzi; R. Carcagno; D. R. Chichili; J. DiMarco; S. Feher; L. Imbasciati; V. V. Kashikhin; M. Lamm; P. J. Limon; D. Orris; P. Schlabach; C. Sylvester; M. Tartaglia; I. Terechkine; J. C. Tompkins; S. Yadav; R. Yamada; A. V. Zlobin
2002-01-01
Two short Nb3Sn dipole models based on a single-bore cos-theta coil with a cold iron yoke were fabricated and tested at Fermilab. This paper summarizes the details of magnet design and fabrication procedure, and reports the test results including quench performance and quench heater studies, and the magnetic measurements.
6. Test of a single module of the J-PET scanner based on plastic scintillators
E-print Network
P. Moskal; Sz. Nied?wiecki; T. Bednarski; E. Czerwi?ski; ?. Kap?on; E. Kubicz; I. Moskal; M. Pawlik-Nied?wiecka; N. G. Sharma; M. Silarski; M. Zieli?ski; N. Zo?; P. Bia?as; A. Gajos; A. Kochanowski; G. Korcyl; J. Kowal; P. Kowalski; T. Kozik; W. Krzemie?; M. Molenda; M. Pa?ka; L. Raczy?ski; Z. Rudy; P. Salabura; A. S?omski; J. Smyrski; A. Strzelecki; A. Wieczorek; W. Wi?licki
2014-08-29
Time of Flight Positron Emission Tomography scanner based on plastic scintillators is being developed at the Jagiellonian University by the J-PET collaboration. The main challenge of the conducted research lies in the elaboration of a method allowing application of plastic scintillators for the detection of low energy gamma quanta. In this article we report on tests of a single detection module built out from BC-420 plastic scintillator strip (with dimensions of 5x19x300mm^3) read out at two ends by Hamamatsu R5320 photomultipliers. The measurements were performed using collimated beam of annihilation quanta from the 68Ge isotope and applying the Serial Data Analyzer (Lecroy SDA6000A) which enabled sampling of signals with 50ps intervals. The time resolution of the prototype module was established to be better than 80ps (sigma) for a single level discrimination. The spatial resolution of the determination of the hit position along the strip was determined to be about 0.93cm (sigma) for the annihilation quanta. The fractional energy resolution for the energy E deposited by the annihilation quanta via the Compton scattering amounts to sigma(E)/E = 0.044/sqrt(E[MeV]) and corresponds to the sigma(E)/E of 7.5% at the Compton edge.
7. Single-column model for atmospheric radiation measurement sites: Model development and sensitivity test
SciTech Connect
Xu, Q.; Dong, M. [Univ. of Oklahoma, Norman, OK (United States)
1995-04-01
A single-column model (SCM) is constructed by extracting the physical subroutines from the community climate model (CCMI) of the National Center for Atmospheric Research. Using observational data obtained from the Oklahoma Atmospheric Radiation Measurement (ARM) site and the National Weather Services, this SCM will perform diagnostic studies of radiation and cloud parameterizations. So far, the model has been tested with simulated data generated by CCM1 global runs. The global runs provide the SCM with initial and lateral boundary conditions that represent the Oklahoma ARM site. The preliminary results can be summarized as follows: the SCM can produce nearly the same results as the CCM1 if the lateral boundary conditions are precisely given from the spectral forms of representation of boundary fluxes; the SCM results are moderately sensitive to noise in the lateral boundary conditions. The SCM simulated temperature can (or cannot) closely follow the CCM1 global run if the noise in the lateral boundary fluxes is below (or above) 10% of the single level. The representativeness of the lateral boundary conditions seems crucial for the SCM simulations. When the advection term is calculated by using the central finite difference scheme from the gridded (instead of spectral) data produced by the CCM1 run, the SCM simulated temperature can differ significantly from that of the CCM1 global run.
8. Single-well tracer push-pull test sensitivity w. r. to fracture aperture and spacing
NASA Astrophysics Data System (ADS)
Ghergut, I.; Behrens, H.; Karmakar, S.; Sauter, M.
2012-04-01
Dealing with a parallel-fracture system of infinite lateral extension, four characteristic regimes of tracer signal sensitivity w. r. to fracture aperture and w. r. to fracture spacing s (whose reciprocal defines fracture density, or the fluid-rock interface area per volume) can be identified during the pull phase of a single-well push-pull test, also depending upon the ratio between push-phase duration Tpush and a characteristic time scale Ts (defined by s2 / D = Ts , with D denoting the tracer's effective diffusion coefficient): early-time regime: tracer signals are sensitive w. r. to fracture aperture, but insensitive w. r. to fracture spacing; sensitivity w. r. to fracture aperture first increases, then decreases with Tpush / Ts (thus there will be an optimum in terms of to Tpush / Ts , at early pull times); mid-time regime: tracer signals are sensitive w. r. to fracture spacing, but insensitive w. r. to fracture aperture; sensitivity w. r. to fracture spacing increases with Tpush / Ts ; late-time regime: with increasing pull duration, tracer signals become increasingly insensitive w. r. to fracture spacing, while regaining sensitivity w. r. to fracture aperture; 'very late'-time regime: sensitivity w. r. to fracture aperture becomes independent upon Tpush / Ts . From these different regimes, some recommendations can be derived regarding the design and dimensioning of dual-tracer single-well push-pull tests for the specific purposes of geothermal reservoir characterization, using conservative solutes and heat as tracers. Acknowledgement: This study is funded by MWK Niedersachsen (Lower-Saxony's Science and Culture Ministry) and by Baker Hughes (Celle) within task unit 'G6' of the Collaborative Research Project 'gebo' (Geothermal Energy and High-Performance Drilling).
9. Analysis of tracer and thermal transients during reinjection
SciTech Connect
Kocabas, I.
1989-10-01
This work studied tracer and thermal transients during reinjection in geothermal reserviors and developed a new technique which combines the results from interwell tracer tests and thermal injection-backflow tests to estimate the thermal breakthrough times. Tracer tests are essential to determine the degree of connectivity between the injection wells and the producing wells. To analyze the tracer return profiles quantitatively, we employed three mathematical models namely, the convection-dispersion (CD) model, matrix diffusion (MD) model, and the Avodnin (AD) model, which were developed to study tracer and heat transport in a single vertical fracture. We considered three types of tracer tests namely, interwell tracer tests without recirculation, interwell tracer tests with recirculation, and injection-backflow tracer tests. To estimate the model parameters, we used a nonlinear regression program to match tracer return profiles to the solutions.
10. Prototype Test Results for the Single Photon Detection SLR2000 Satellite Laser Ranging System
NASA Technical Reports Server (NTRS)
Zagwodzki, Thomas W.; McGarry, Jan F.; Degnan, John J.; Cheek, Jack W.; Dunn, Peter J.; Patterson, Don; Donovan, Howard
2004-01-01
11. Transient Ischemic Attack
MedlinePLUS
NINDS Transient Ischemic Attack Information Page Synonym(s): Mini Stroke Table of Contents (click to jump to sections) What is ... Trials Organizations Additional resources from MedlinePlus What is Transient Ischemic Attack? A transient ischemic attack (TIA) is ...
12. Liquid oxygen/hydrogen testing of a single swirl coaxial injector element in a windowed combustion chamber
NASA Astrophysics Data System (ADS)
Hulka, J.; Makel, D.
1993-06-01
A modular, high pressure, liquid rocket single element combustion chamber was developed at Aerojet for use with nonintrusive combustion diagnostics. The hardware is able to accommodate full-size injection elements and includes a recessed annular injector around the single element to provide a source for hot gas background flow, which reduces recirculation in the chamber and provides additional injection mass to elevate chamber pressure. Experiments are being conducted to develop the diagnostics required to characterize a single-element combustion spray field for combustion modeling, benchmark data for CFD model validation, and development of the transfer functions between single element cold flow and multielement hot fire. The latter task is being pursued using an injector element identical to elements that had been previously cold-flow tested in single element tests to ambient backpressure and hot fire tested in a multielement injector. Preliminary tests conducted to date without hydrogen flowing through the annular coaxial orifice of the single element show the general flow characteristics of a reacting, unconfined, liquid oxygen hollow cone swirl spray.
13. Transient receptor potential cation channel A1 (TRPA1) mediates changes in heart rate variability following a single exposure to acrolein in mice
EPA Science Inventory
The data show that a single exposure to acrolein causes autonomic imbalance in mice through the TRPA1 sensor and subsequent cardiac dysfunction. Human and animal studies have shown that short-term air pollution exposure causes...
14. Test plan for determining breathing rates in single shell tanksusing tracer gases. Revision 1
SciTech Connect
Andersen, J.A.
1997-06-20
This test plan specifies the requirements and conditions for the injection of tracer gas (Helium (He)) into single shell tanks to determine breathing rates using periodic sampling. The eight tanks which have been selected at the time this Test Plan was developed are A-101, AX-102, AX-103, BY-105, C-107, U-103 (U-103 is counted twice, once during the winter months and once during the summer), and U-105. Other tanks to be sampled will be assigned by Pacific Northwest National Laboratory (PNNL) at a later date in the study process as resources allow, the document shall be revised as required. The sampling of headspace for each of these tanks shall be performed using available risers or the Standard Hydrogen Monitoring System (SHMS) cabinet as available. The tank farm vapor cognizant engineer shall assign the injection and sample testing point for each tank and document the point in the field work package. SUMMA TMI canisters, equipped in-line with dual particulate air filters and two silica gel sorbent traps will be used to collect the gas samples. The purpose of dual particulate air filters is to ensure no radioactive particulates are transferred to the SUMMA TMI canisters. The silica gel sorbent traps will effectively eliminate any tritiated water vapor that may be present in the sample gas stream. PNNL shall supply the tracer gases injection system and shall perform the analysis on the headspace samples. TWRS Characterization project shall inject the tracer gas and perform the sampling. Refer to Engineering Task Plan HNF-SD-TWR-ETP-002 for a detailed description of the responsibilities for this task.
15. Transient based protection using current transients
Xia Mingchao; Huang Yizhuang
2008-01-01
A transient based protection criterion using the wavelet transform results of current transients from the two ends or three ends (T-type line) of high voltage power transmission line is presented. According to the attenuation effects of high voltage transmission line and busbar capacitance to high-frequency current transients, differences of current transients at each end of the transmission line when in-zone
16. Commentary: On the limited role of the single-subject design in psychology: Hypothesis generating but not testing
John J. Furedy
1999-01-01
The single-subject design (which really denotes a design that employs too few subjects to allow statistical inferences concerning significance to be made) is useful only for the generation, but not for the testing or evaluation, of hypotheses concerning any psychological function. Those hypotheses that may be suggested by the single-subject design include ones about within-subject developmental effects (which may need
17. A method for measuring the fracture toughness of micrometer-sized single crystal silicon by tensile test
K. Li; Takashi Kasai; Shigeki Nakao; Hiroshi Tanaka; Taeko Ando; Mitsuhiro Shikida; Kazuo Sato
2003-01-01
We developed a method of measuring the fracture toughness,-which is a material constant in the macroscopic domain, of single crystal silicon on a micrometer-scale. We notched the thin film specimen on a single edge and then conducted uniaxial tensile test to failure. The average value of measured fracture toughness of specimens on the (100) plane was 1.58 MPam12\\/ with scatter.
18. Enhancing the Fibre Matrix Adhesion of Natural Fibre Reinforced Polypropylene by Electron Radiation Analyzed with the Single Fibre Fragmentation Test
Tim Huber; Udo Biedermann; Jrg Mssig
2010-01-01
The effects of electron radiation on natural fibre reinforced polypropylene have been analyzed with the single fibre fragmentation test. Specimens of single hemp, flax, ramie and cotton fibres\\/fibre bundles embedded in a polypropylene sheet were irradiated with electron radiation of 10 MeV with intensities of 5, 15 and 33 kGy. The radiation led to a strain reduction of the polypropylene
19. CHARACTERIZATION TESTING AND ANALYSIS OF SINGLE CELL SO2 DEPOLARIZED ELECTROLYZER
SciTech Connect
Steimke, J; Timothy Steeper, T
2006-09-15
This document reports work performed at the Savannah River National Laboratory (SRNL) that further develops the use of a proton exchange membrane or PEM-type electrochemical cell to produce hydrogen via SO{sub 2}-depolarized water electrolysis. This work was begun at SRNL in 2005. This research is valuable in achieving the ultimate goal of an economical hydrogen production process based on the Hybrid Sulfur (HyS) Cycle. The HyS Process is a hybrid thermochemical cycle that may be used in conjunction with advanced nuclear reactors or centralized solar receivers to produce hydrogen by water-splitting. Like all other sulfur-based cycles, HyS utilizes the high temperature thermal decomposition of sulfuric acid to produce oxygen. The unique aspect of HyS is the generation of hydrogen in a water electrolyzer that is operated under conditions where dissolved sulfur dioxide depolarizes the anodic reaction, resulting in substantial voltage reduction. Sulfur dioxide is oxidized at the anode, producing sulfuric acid that is sent to the acid decomposition portion of the cycle. The focus of this work was to conduct single cell electrolyzer tests in order to prove the concept of SO{sub 2}-depolarization and to determine how the results can be used to evaluate the performance of key components of the HyS Process. A test facility for conducting SO{sub 2}-depolarized electrolyzer (SDE) testing was designed, constructed and commissioned. The maximum cell current is 50 amperes, which is equivalent to a hydrogen production rate of approximately 20 liters per hour. Feed to the anode of the electrolyzer is sulfuric acid solutions containing dissolved sulfur dioxide. The partial pressure of sulfur dioxide may be varied in the range of 1 to 6 atm (15 to 90 psia). Temperatures may be controlled in the range from ambient to 80 C. Hydrogen generated at the cathode of the cell is collected for the purpose of flow measurement and composition analysis. The test facility proved to be easy to operate, versatile, and reliable.
20. Transient global amnesia mimics: Transient epileptic amnesia
PubMed Central
Nicastro, Nicolas; Picard, Fabienne; Assal, Frederic
2014-01-01
We describe the case of a 79-year-old patient referred for suspected transient global amnesia, after an episode of anterograde amnesia which lasted 90min. An EEG, performed after the episode, showed bilateral temporal electrographic seizures, orienting the diagnosis toward a transient epileptic amnesia. Transient epileptic amnesia is defined by temporal lobe epilepsy characterized by recurrent transient amnestic episodes of 3090min in duration, sometimes associated with olfactory hallucinations or oral automatisms. Response to antiepileptic drugs is excellent. We would like to raise awareness toward this epileptic amnesia when facing atypical or recurrent transient amnestic episodes. PMID:25667881
1. Tracer Tests in a Fractured Dolomite: 2. Controls on Mass-Recovery Rates for a Single-Porosity, Heterogeneous Conceptualization
SciTech Connect
Altman, S.J.; Meigs, L.C.; Jones, T.L.
1999-03-04
A single-well injection-withdrawal (SWIW) test is evaluated as a tool to differentiate between single- and double-porosity conceptualizations of a system. Results from single-porosity simulations incorporating plume drift are also compared to observed data from a recent series of SWIW tests conducted in a fractured dolomite unit, for which a double-porosity conceptualization has been proposed. We evaluate the difficulty of differentiating the response for a double-porosity conceptualization from that for a heterogeneous, single-porosity conceptualization incorporating plume drift. Results of sensitivity studies on multiple, stochastically generated, heterogeneous transmissivity fields indicate that to simulate extremely slow mass-recovery rates for a SWIW test with a single-porosity conceptualization, the following conditions must be present: plume drift, extreme heterogeneities (high {sigma}InT), and an unusual configuration of the high and low transmissivity regions relative to the well location. A compilation of existing data suggests that the high degree of heterogeneity necessary is rare at the SWIW test scale.The observed data from the SWIW tracer tests cannot be matched to numerical simulation results when a single-porosity conceptualization is assumed. A signature of significant drift is less than 100% mass recovery with a zero derivative with respect to time of the late-time normalized cumulative mass curve indicating mass transported outside the capture zone of the withdrawal well. To minimize the risk of misinterpretation, an important design feature for SWIW tests is the collection of late-time data so that percent total mass recovery can be calculated.
2. Study on a test of optical stochastic cooling scheme in a single pass beam line
SciTech Connect
Chattopadhyay, S.; Kim, C.; Massoletti, D.; Zholents, A. [and others
1997-01-01
A feasibility study of an experiment to test the principle of optical stochastic cooling is presented. We propose to build a new beamline in the extraction area of the ALS Booster synchrotron, where we will include a bypass lattice similar to the lattice that could be used in the cooling insertion in a storage ring. Of course, in the single pass beamline we cannot achieve cooling, but we can test all the functions of the bypass lattice that are required to achieve cooling in a storage ring. As it is stated in, there are stringent requirements on the time-of-flight properties of the bypass lattice employed in a cooling scheme. The pathlengths of particle trajectories in the bypass must be fairly insensitive to the standard set of errors that usually affect the performance of storage rings. Namely, it is necessary to preserve all fluctuations in the longitudinal particle density within the beam from the beginning to the end of the bypass lattice with the accuracy of {lambda}/2{pi}, where A is the carrying (optical) wavelength. According to, cooling will completely vanish if a combined effect of all kinds of errors will produce a spread of the pathlengths of particle trajectories larger than {lambda}/2 and the cooling time will almost double if the spread of the pathlengths is {lambda}/2{pi}. At a first glance, {lambda}/2{pi} {approx_equal} 0.1/{mu}m is such a small value that satisfying this accuracy looks nearly impossible. However, simulations show that a carefully designed bypass can meet all the requirements even with rather conservative tolerance to errors.
3. Prediction of haloperidol steady-state levels in plasma after a single test dose.
PubMed
Javaid, J I; Janicak, P G; Sharma, R P; Leach, A M; Davis, J M; Wang, Z
1996-02-01
Because of large interindividual variabilities in the pharmacokinetics of haloperidol (HPDL), empirically adjusting the dose to achieve steady-state levels in plasma (Css) is a time-consuming process. We report a method to individualize dose to achieve a desired Css from an observed drug level 24 hours after a single 15-mg test dose of HPDL. Drug-free schizophrenic and schizo-affective patients were blindly and randomly assigned to achieve a low (< 5 ng/ml), medium (10-18 ng/ml), or high (> 25 ng/ml) Css range of HPDL. On day 1 of the study, each patient received an oral "test" dose of HPDL (15 mg), and blood was drawn 24 hours later to determine drug levels in plasma (C24h). The first 34 patients (group I) were then maintained empirically on 2, 5 to 8, or 10 to 15 mg twice daily of oral HPDL concentrate for 5 days to achieve a low, medium, or high Css range, respectively. For the next 58 patients (group II), the dose of HPDL to achieve the assigned Css range was computed by using C24h in a prediction formula. Application of the C24h correctly predicted the maintenance dose required to achieve the Css in 73.2% of the cases. Further, there was a highly significant correlation (R2 = 0.877, p < 0.0001) between the predicted dose and the actual dose required to achieve the targeted Css range. On the basis of these results, we have formulated a nomogram to help predict the maintenance dose required to achieve low, medium, or high HPDL targeted ranges at various C24h values. PMID:8834418
4. Single-Event Effects Ground Testing and On-Orbit Rate Prediction Methods: The Past, Present and Future
NASA Technical Reports Server (NTRS)
Reed, Robert A.; Kinnison, Jim; Pickel, Jim; Buchner, Stephen; Marshall, Paul W.; Kniffin, Scott; LaBel, Kenneth A.
2003-01-01
Over the past 27 years, or so, increased concern over single event effects in spacecraft systems has resulted in research, development and engineering activities centered around a better understanding of the space radiation environment, single event effects predictive methods, ground test protocols, and test facility developments. This research has led to fairly well developed methods for assessing the impact of the space radiation environment on systems that contain SEE sensitive devices and the development of mitigation strategies either at the system or device level.
5. Fracture trace map and single-well aquifer test results in a carbonate aquifer in Berkeley County, West Virginia
USGS Publications Warehouse
McCoy, Kurt J.; Podwysocki, Melvin H.; Crider, E. Allen; Weary, David J.
2005-01-01
These data contain information on the results of single-well aquifer tests, lineament analysis, and a bedrock geologic map compilation for the low-lying carbonate and shale areas of eastern Berkeley County, West Virginia. Efforts have been initiated by management agencies of Berkeley County in cooperation with the U.S. Geological Survey to further the understanding of the spatial distribution of fractures in the carbonate regions and their correlation with aquifer properties. This report presents transmissivity values from about 200 single-well aquifer tests and a map of fracture-traces determined from aerial photos and field investigations. Transmissivity values were compared to geologic factors possibly affecting its magnitude.
6. Coaxial HOM Coupler designs tested on a single cell niobium cavity
SciTech Connect
Peter Kneisel; Genfa Wu; Gianluigi Ciovati; Jacek Sekutowicz
2006-08-28
Coaxial higher order mode (HOM) couplers have been developed for HERA cavities and are used in TESLA, SNS and JLab upgrade cavities. The principle of operation is the rejection of the fundamental mode by the tunable filter of the coupler and the transmission of the HOMs. It has been recognized recently that inappropriate thermal designs of the feedthrough for the pick-up probe of the HOM coupler will not sufficiently carry away the heat generated in the probe tip by the fundamental mode fields, causing a built-up of the heating of the niobium probe tip and subsequently, a deterioration of the cavity quality factor has been observed in CW operation. An improvement of the situation has been realized by a better thermal design of the feedthrough incorporating a sapphire rf window [1]. An alternative is a modification of the coupler loop (?F? ? part) with an extension towards the pick-up probe. This design has been tested on a single cell niobium cavity in comparison to a ''standard TESLA'' configuration by measuring the Eacc behavior at 2 K. The measurements clearly indicate that the modified version of the coupler loop is thermally much more stable than the standard version.
7. Human-based systems in drug and chemical safety testing--toward replacement, the 'single R'.
PubMed
Coleman, Robert A
2014-12-01
The Three Rs was a concept originally conceived as a means of reducing the suffering of laboratory animals that are used largely in identifying any potential safety issues with chemicals to which humans may be exposed. However, with growing evidence of the shortcomings of laboratory animal testing to reliably predict human responsiveness to such chemicals, questions are now being asked as to whether it is appropriate to use animals as human surrogates at all. This raises the question of whether, of the original Three Rs, two--Reduction and Refinement--are potentially redundant, and whether, instead, we should concentrate on the third R: Replacement. And if this is the best way forward, it is inevitable that this R should be based firmly on human biology. The present review outlines the current state-of-the-art regarding our access to human biology through in vitro, in silico and in vivo technologies, identifying strengths, weaknesses and opportunities, and goes on to address the prospect of achieving a single R, with some suggestions as to how to progress toward this goal. PMID:25635644
8. On The Way To Off-equatorial Charged Discs Near Compact Objects - Single Test Particles Approximation
NASA Astrophysics Data System (ADS)
Kovar, Jiri; Kopacek, O.; Karas, V.; Stuchlik, Z.
2010-02-01
We present our recent studies of charged particles motion out of the equatorial plane in strong gravitational and electromagnetic fields. Within the general relativistic approach, we have demonstrated that the interplay between gravitational and electromagnetic action may allow for stable off-equatorial circular motion along the so-called halo orbits near compact objects, such as rotating magnetic compact stars and Kerr black holes immersed in an asymptotically uniform magnetic field of external origin. Locations of halo orbits correspond to minima of the two-dimensional effective potential, which exhibits several qualitativelly different kinds of behaviour, reflecting the charge of moving particles and orientation of the motion. Along with the study of the halo motion itself, we have discussed the general motion in the related off-equatorial potential lobes, demonstrating its chaoticness or regularity in terms of the Poincar surfaces of sections and recurrence plots. A possible outlook of this study is to build a single test particles model of putative circumpulsar discs consisting of charged dust particles. Institute of Physics and Astronomical Institute have been operated under the projects MSM 4781305903 and AV 0Z10030501, and further supported by the Centre for Theoretical Astrophysics LC06014 in the Czech Republic. JK, VK and ZS thank the Czech Science Foundation (ref. P209/10/P190, 205/07/0052, 202/09/0772). OK acknowledges the doctoral student program of the Czech Science Foundation (205/09/H033).
9. Emerging optocoupler issues with energetic particle-induced transients and permanent radiation degradation
SciTech Connect
Reed, R.A.; Barth, J.L.; LaBel, K.A. [NASA/GSFC, Greenbelt, MD (United States)] [NASA/GSFC, Greenbelt, MD (United States); Marshall, P.W.; Carts, M.A. [NRL/SFA, Largo, MD (United States)] [NRL/SFA, Largo, MD (United States); Johnston, A.H. [JPL, Pasadena, CA (United States)] [JPL, Pasadena, CA (United States); Marshall, C.J. [NRL, Washington, DC (United States)] [NRL, Washington, DC (United States); DOrdine, M. [Ball Aerospace, Boulder, CO (United States)] [Ball Aerospace, Boulder, CO (United States); Kim, H.S. [Jackson and Tull Chartered Engineers, Washington, DC (United States)] [Jackson and Tull Chartered Engineers, Washington, DC (United States)
1998-12-01
Radiation-induced permanent degradation and single event transient effects for optocouplers are discussed in this paper. These two effects are independent to the first order and will be addressed separately. Displacement damage-induced degradation of optocoupler current transfer ratio is reviewed. New data are presented that show the importance of application specific testing and that generalized quantification of optocoupler CTR degradation can lead to incorrect predictions of actual circuit performance in a radiation environment. Data are given for various circuit loading and drive current parameters. Previous work that introduces the idea that two mechanisms exist for inducing transients on the optocoupler output is discussed. New data are presented that extends the evidence of this dual mechanism hypothesis. In this work measurements show that single event transient cross sections and transient propagation varies with circuit filtering. Finally, the authors discuss utilization of the optocouplers in the space environment. New data are applied to two examples: one on permanent degradation and the other on single event transient rates in high bandwidth applications.
10. Racial/ethnic and gender differences among older adults in nonmonogamous partnerships, time spent single, and HIV testing
PubMed Central
Harawa, Nina T.; Leng, Mei; Kim, Junyeop; Cunningham, William Emery
2011-01-01
Background A higher frequency of nonmonogamy, due in part to lower marriage prevalence, may contribute to elevated HIV/STD rates among older Blacks. Methods To examine race and gender differences in nonmonogamy, time spent single (i.e., not married or cohabiting), and HIV testing in older adults, we analyzed U.S. population-based data from the 2005-06 National Social Life, Health, and Aging Project (NSHAP) for 2,825 heterosexual participants ages 57-85 years. Results Blacks spent greater portions of their adult lives single than did Hispanics or Whites and were far more likely to report recent nonmonogamous partnerships (23.4% vs. 10.0% and 8.2%). Among individuals reporting sex in the prior 5 years, nonmonogamous partnerships were strongly associated with time spent single during the period. Control for time spent single and other covariates reduced the association of Black race with nonmonogamous partnerships for men but increased it for women. Less than 20% reported ever testing for HIV; less than 6% had been recommended testing by a provider. Testing rates, highest in Black men and White women, differed little by history of nonmonogamous partnerships within gender strata. Conclusions Singlehood helps to explain higher nonmonogamous partnership rates in older Black men but not older Black women. Older adults rarely receive or are recommended HIV testing, a key strategy for reducing heterosexual HIV transmission. PMID:22082721
11. Transient voltage dip analysis using the transient energy function method
1990-01-01
It is shown that the transient energy function (TEF) method provides a fast approximate approach to voltage dip computations. The TEF method is used to predict the stability of a power system after a disturbance has occurred. The results of application of the technique to test power systems confirmed that the voltage dips predicted by the TEF method compare well
12. Comparison of the results of short-term static tests and single-pass flow-through tests with LRM glass.
SciTech Connect
Ebert, W. L.; Chemical Engineering
2007-01-29
Static dissolution tests were conducted to measure the forward dissolution rate of LRM glass at 70 C and pH(RT) 11.7 {+-} 0.1 for comparison with the rate measured with single-pass flow-through (SPFT) tests in an interlaboratory study (ILS). The static tests were conducted with monolithic specimens having known geometric surface areas, whereas the SPFT tests were conducted with crushed glass that had an uncertain specific surface area. The error in the specific surface area of the crushed glass used in the SPFT tests, which was calculated by modeling the particles as spheres, was assessed based on the difference in the forward dissolution rates measured with the two test methods. Three series of static tests were conducted at 70 C following ASTM standard test method C1220 using specimens with surfaces polished to 600, 800, and 1200 grit and a leachant solution having the same composition as that used in the ILS. Regression of the combined results of the static tests to the affinity-based glass dissolution model gives a forward rate of 1.67 g/(m{sup 2}d). The mean value of the forward rate from the SPFT tests was 1.64 g/(m{sup 2}d) with an extended uncertainty of 1.90 g/(m{sup 2}d). This indicates that the calculated surface area for the crushed glass used in the SPFT tests is less than 2% higher than the actual surface area, which is well within the experimental uncertainties of measuring the forward dissolution rate using each test method. These results indicate that the geometric surface area of crushed glass calculated based on the size of the sieves used to isolate the fraction used in a test is reliable. In addition, the C1220 test method provides a means for measuring the forward dissolution rate of borosilicate glasses that is faster, easier, and more economical than the SPFT test method.
13. Investigation of the single case in neuropsychology: confidence limits on the abnormality of test scores and test score differences
J. R. Crawford; Paul H. Garthwaite
2002-01-01
Neuropsychologists often need to estimate the abnormality of an individual patients test score, or test score discrepancies, when the normative or control sample against which the patient is compared is modest in size. Crawford and Howell [The Clinical Neuropsychologist 12 (1998) 482] and Crawford et al. [Journal of Clinical and Experimental Neuropsychology 20 (1998) 898] presented methods for obtaining point
14. Evaluation of size effect on mechanical properties of single crystal silicon by nanoscale bending test using AFM
Takahiro Namazu; Yoshitada Isono; Takeshi Tanaka
2000-01-01
This paper describes a nanometer-scale bending test for a single crystal silicon (Si) fixed beam using an atomic force microscope (AFM). This research focuses on revealing the size effect on the mechanical property of Si beams ranging from a nano- to millimeter scale. Nanometer-scale Si beams, with widths from 200 to 800 nm and a thickness of 255 nm, were
15. Testing a Poisson Counter Model for Visual Identification of Briefly Presented, Mutually Confusable Single Stimuli in Pure Accuracy Tasks
ERIC Educational Resources Information Center
Kyllingsbaek, Soren; Markussen, Bo; Bundesen, Claus
2012-01-01
The authors propose and test a simple model of the time course of visual identification of briefly presented, mutually confusable single stimuli in pure accuracy tasks. The model implies that during stimulus analysis, tentative categorizations that stimulus i belongs to category j are made at a constant Poisson rate, v(i, j). The analysis is
16. Fusion method for the measurement of plutonium in soils: Single-laboratory evaluation and interlaboratory collaborative test
P. B. Hahn; E. W. Bretthauer; P. B. Altringer; N. F. Mathews
1977-01-01
The results of a single laboratory evaluation and an interlaboratory collaborative test of a method for measuring plutonium in soil are presented. The method employs potassium fluoride and potassium pyrosulfate fusions to decompose a 10 gram sample, barium sulfate precipitations, solvent extraction and electrodeposition to isolate the plutonium, and alpha spectrometry to measure the plutonium. Also discussed are several problem
17. Simplified single sample 13Carbon urea breath test for Helicobacter pylori: comparison with histology, culture, and ELISA serology
R P Logan; R J Polson; J J Misiewicz; G Rao; N Q Karim; D Newell; P Johnson; J Wadsworth; M M Walker; J H Baron
1991-01-01
There is no ideal method for detecting Helicobacter pylori. The 'standard' 13Carbon urea breath test (13C-UBT), which involves collecting eight to 15 breath samples and subsequent costly analysis, was modified by pooling 21 samples of expired breath taken at five minute intervals for 40 minutes into a collecting bag, from which a single 20 ml aliquot was taken and analysed
18. A Field-Tested Task Analysis for Creating Single-Subject Graphs Using Microsoft[R] Office Excel
ERIC Educational Resources Information Center
Lo, Ya-yu; Konrad, Moira
2007-01-01
Creating single-subject (SS) graphs is challenging for many researchers and practitioners because it is a complex task with many steps. Although several authors have introduced guidelines for creating SS graphs, many users continue to experience frustration. The purpose of this article is to minimize these frustrations by providing a field-tested
19. Estimation of interfacial shear strength: an application of a new statistical theory for single fiber composite test
C. Y. Hui; D. Shia; L. A. Berglund
1999-01-01
A simple procedure is proposed for estimating the effect of different sizings on the strength of fiber\\/matrix interface. This procedure is based on a newly developed statistical theory for single-fiber composite tests. This procedure is used to evaluate the interfacial shear strength of HTA carbon fiber in an epoxy matrix with two different sizings. It is shown that if the
20. A Single-Crate Stand-Alone CAMAC Control System for a Negative Ion Source Test Facility
Raymond C. Juras; Norval F. Ziegler
1979-01-01
A single-crate CAMAC system was configured to control a negative ion source development facility at ORNL and control software was written for the crate microcomputer. The software uses inputs from a touch panel and a shaft encoder to control the various operating parameters of the test facility and uses the touch panel to display the operating status. Communication to and
1. FUSION METHOD FOR THE MEASUREMENT OF PLUTONIUM IN SOILS: SINGLE-LABORATORY EVALUATION AND INTERLABORATORY COLLABORATIVE TEST
EPA Science Inventory
This report presents the results of a single-laboratory evaluation and an interlaboratory collaborative test of a method for measuring plutonium in soil. The method employs potassium fluoride and potassium pyrosulfate fusions to decompose a 10-gram sample, barium sulfate precipit...
2. Criticality of Low-Energy Protons in Single-Event Effects Testing of Highly-Scaled Technologies
NASA Technical Reports Server (NTRS)
Pellish, Jonathan A.; Marshall, Paul W.; Rodbell, Kenneth P.; Gordon, Michael S.; LaBel, Kenneth A.; Schwank, James R.; Dodds, Nathaniel A.; Castaneda, Carlos M.; Berg, Melanie D.; Kim, Hak S.; Phan, Anthony M.; Seidleck, Christina M.
2014-01-01
We report low-energy proton and low-energy alpha particle single-event effects (SEE) data on a 32 nm silicon-on-insulator (SOI) complementary metal oxide semiconductor (CMOS) latches and static random access memory (SRAM) that demonstrates the criticality of using low-energy protons for SEE testing of highly-scaled technologies. Low-energy protons produced a significantly higher fraction of multi-bit upsets relative to single-bit upsets when compared to similar alpha particle data. This difference highlights the importance of performing hardness assurance testing with protons that include energy distribution components below 2 megaelectron-volt. The importance of low-energy protons to system-level single-event performance is based on the technology under investigation as well as the target radiation environment.
3. Platelet function testing during 5-day storage of single and random donor plateletpheresis.
PubMed
Akay, O Meltem; Gndz, Eren; Ba?yi?it, Hatice; Gulbas, Zafer
2007-06-01
Platelet concentrates are routinely manufactured from whole blood by differential centrifugation (random donor platelets-RDP) or by plateletpheresis (single donor platelets-SDP). These platelet concentrates have a storage period of 5 days and many different approaches exist to measure the condition of platelets during their storage. In this study, platelet aggregation testing using adenosine diphosphate (ADP) and collagen and flow cytometric platelet activation analysis using CD41 FITC and CD62 PE before and after ADP was performed on days 1, 3 and 5 of storage of platelet preparations. Thirty three RDPs, stored in Baxter and Kansuk blood bags and 18 SDPs stored in Fresenius blood bags were evaluated. In RDPs and in SDPs; ADP and collagen induced PA responses were decreased significantly on the 3rd and 5th days compared to 1st day. CD62 positive platelet percentage after ADP were decreased significantly on the 3rd and 5th days compared to the 1st day in Kansuk bags. Flow cytometric analysis revealed minor changes in CD41 expression after ADP on the 3rd day compared to 1st day and on the 5th day compared to 3rd day. Differences in CD62 positive platelet percentage were not significant between the RDPs and SDPs. Our results suggest that: (1) ADP and collagen induced PA responses decrease both in RDPs and SDPs during storage. (2) Flow cytometric analysis does not show major significant changes in platelet activation after ADP during storage. (3) Continous shaking on the agitator does not cause a significant change in CD62 positive platelet percentage during storage. (4) Platelet aggregation responses in RDPs stored in Baxter and Kansuk blood bags do not differ during storage. PMID:17602871
4. Scaling submillimeter single-cycle transients toward megavolts per centimeter field strength via optical rectification in the organic crystal OH1.
PubMed
Ruchert, Clemens; Vicario, Carlo; Hauri, Christoph P
2012-03-01
We present the generation of high-power single-cycle terahertz (THz) pulses in the organic salt crystal 2-[3-(4-hydroxystyryl)-5.5-dimethylcyclohex-2-enylidene]malononitrile or OH1. Broadband THz radiation with a central frequency of 1.5 THz (?(c)=200 ?m) and high electric field strength of 440 kV/cm is produced by optical rectification driven by the signal of a powerful femtosecond optical parametric amplifier. A 1.5% pump to THz energy conversion efficiency is reported, and pulse energy stability better than 1% RMS is achieved. An approach toward the realization of higher field strength is discussed. PMID:22378431
5. Evaluating the clinical relevance of food sensitivity tests: a single subject experiment.
PubMed
Herman, Patricia M; Drost, Lisa M
2004-06-01
A number of tests are available to identify food sensitivities. This article presents an analysis of the diagnostic value of nine different food sensitivity tests run concurrently on a healthy 33-year-old female with a previous diagnosis of environmental allergies. This case study evaluated conventional allergy tests (skin prick and serum IgE), tests of other immune-mediated reactions (serum IgG and salivary IgA), and tests that claim to measure the energetic reaction of the whole person to particular foods (kinesiology, Vega, and Carroll testing). The results of an elimination/challenge test were used as indicators of true food reactions in order to calculate the sensitivity, specificity, and positive predictive value (PPV) of each test. In a separate evaluation, the variability of results across the four tests measuring IgG was determined. Results show several tests (one of the two serum tests of IgG alone, both serum tests of IgE and IgG, skin prick testing, and Carroll testing) may have very high (100 percent) specificity and PPV when test results are compared to the results of an elimination/challenge test. Sensitivity, however, is low across tests (50-60 percent), likely because different tests measure different mechanisms of food reactions and because food sensitivities can be the result of a number of different mechanisms. Very little consistency was found among the results of the four tests measuring IgG - 79-83 percent disagreement. This study shows a number of tests may be useful in identifying foods to which a patient is reactive; however, no one test is likely to identify all reactive foods. PMID:15253678
6. Workshop on Radio Transients
NASA Astrophysics Data System (ADS)
Croft, Steve; Gaensler, Bryan
2012-04-01
7. Out-of-School Time Program Test Score Impact for Black Children of Single-Parents
ERIC Educational Resources Information Center
Nagle, Barry T.
2013-01-01
Out-of-School Time programs and their impact on standardized college entrance exam scores for black or African-American children of single parents who have applied for a competitive college scholarship program is the study focus. Study importance is supported by the large percentage of black children raised by single parents, the large percentage
8. The anomaly in a breakthrough curve of a single well "push-pull" tracer test: A density driven effect?
NASA Astrophysics Data System (ADS)
Zeilfelder, Sarah; Hebig, Klaus; Ito, Narimitsu; Machida, Isao; Scheytt, Traugott; Marui, Atsunao
2013-04-01
What method is appropriate to investigate an aquifer when there is only one well available? A single well "push-pull" tracer test (PP Test) may be a suitable method in order to characterize an aquifer and to obtain information about the hydraulic and chemical properties when only one well is available for the investigations. In a PP test, a test solution that contains a known amount of solutes and a conservative tracer is injected into the aquifer ("push") and extracted afterwards ("pull"). Optionally, the test solution is flushed out of the well and the casing with untreated test solution with a so called "chaser" before being extracted. Also between the injection and the extraction phase a drifting time may be included. The breakthrough of the tracer during the extraction phase is measured and used for analyses and interpretation. In the last three years, several PP Test campaigns were conducted at two different test sites in Japan (Hebig et al. 2011, Zeilfelder et al. 2012). The aim was to investigate the applicability of the PP Test method in different geological settings and in different types of aquifers. The latest field campaign thus focussed on the question how variations of the setup are influencing the breakthrough curve of the PP Test in order to develop and enhance this method. Also the standardization of the PP Test was an aim of this study. During the campaign, a total of seven PP Tests were performed, while only single aspects of the setup were varied from test to test. The tests differed in injection and extraction rate, in the salinity of the injected test solution and in the use of a chaser solution. The general shapes of the breakthrough curves were similar and conclusions about the repeatability of the PP Test could be drawn. However, a sharp anomaly was observed in the breakthrough curve of one specific setup type. By repeating this PP test under the same boundary conditions, we were able to recreate the anomaly and could exclude any technical aspects as a source. In this version of the PP test higher salinized test solution was injected into the aquifer. There are several hypotheses that could explain the behavior of the breakthrough curves of the tracer in this test design. Of all the possibilities (like sorption processes, unexpected tracer reactions, inhomogeneities in the aquifer, influence of the well design), we assume that ion exchange processes and density driven flow are the main reasons for the repeatedly observed anomaly. References: Hebig, K.H., Ito, N., Scheytt, T.J. & Marui, A. (2011). Hydraulic and hydrochemical characterization of deep coastal sedimentary basins by single-well Push-Pull tests. GSA Annual Meeting, 9-12 October 2011, Minneapolis, USA. Zeilfelder, S., Ito, N., Marui, A., Hebig, K. & Scheytt, T. (2012). Push-Pull-Test und Tracer-Test in einem tiefen Grundwasserleiter in Kameoka, Japan. Kurzfassung in: Liedl, R., Burghardt, D., Simon, E., Reimann, T. & Kaufmann-Knoke (Hg.). Grundwasserschutz und Grundwassernutzung. Tagung der Fachsektion Hydrogeologie in der DGG (FH-DGG). 16. - 20. Mai 2012, Dresden. Kurfassungen der Vortrge und Poster. Schriftenreihe der DGG, Heft 78, S. 192.
9. High-power tests of a single-cell copper accelerating cavity driven by two input couplers.
SciTech Connect
Horan, D.; Bromberek, D.; Meyer, D.; Waldschmidt, G.; Accelerator Systems Division (APS)
2008-01-01
High-power tests were conducted on a 350-MHz, single-cell copper accelerating cavity driven simultaneously by two H-loop input couplers for the purpose of determining the reliability, performance, and power-handling capability of the cavity and related components, which have routinely operated at 100-kW power levels. The test was carried out utilizing the APS 350-MHz RF Test Stand, which was modified to split the input rf power into two frac12-power feeds, each supplying power to a separate H-loop coupler on the cavity. Electromagnetic simulations of the two-coupler feed system were used to determine coupler match, peak cavity fields, and the effect of phasing errors between the coupler feed lines. The test was conducted up to a maximum total rf input power of 164-kW CW. Test apparatus details and performance data will be presented.
10. Techniques for analyzing electromagnetic transients
H. W. Dommel
1997-01-01
With few exceptions, power system electromagnetic transients must be studied on a three-phase basis rather than on a positive sequence single-phase basis. For example, the three-phase opening of a circuit breaker is no longer a symmetric event in the ms range. Current interruption takes place at current zero, and one phase would open first at its current zero, while the
11. Bilayers merge even when exocytosis is transient
PubMed Central
Taraska, Justin W.; Almers, Wolfhard
2004-01-01
During exocytosis, the lumen of secretory vesicles connects with the extracellular space. In some vesicles, this connection closes again, causing the vesicle to be recaptured mostly intact. The degree to which the bilayers of such vesicles mix with the plasma membrane is unknown. Work supporting the kiss-and-run model of transient exocytosis implies that synaptic vesicles allow neither lipid nor protein to escape into the plasma membrane, suggesting that the two bilayers never merge. Here, we test whether neuroendocrine granules behave similarly. Using two-color evanescent field microscopy, we imaged the lipid probe FM4-64 and fluorescent proteins in single dense core granules. During exocytosis, granules lost FM4-64 into the plasma membrane in small fractions of a second. Although FM4-64 was lost, granules retained the membrane protein, GFP-phogrin. By using GFP-phogrin as a probe for resealing, it was found that even granules that reseal lose FM4-64. We conclude that the lipid bilayers of the granule and the plasma membrane become continuous even when exocytosis is transient. PMID:15173592
12. Transient Pressure Analysis in Strip Reservoirs with Linear
E-print Network
Stanford University
SGP-TR-97 Transient Pressure Analysis in Strip Reservoirs with Linear Skin Discontinuities reveal important geometrical features of the reservoir boundary. And, based on the pressure transient of analysing pressure transient tests for linear skin discontinuities is presented. The case of a strip
13. Development and Preclinical Testing of a High Affinity Single Chain Antibody against (+)-Methamphetamine
PubMed Central
Peterson, Eric C.; Laurenzana, Elizabeth M.; Atchley, William T.; Hendrickson, Howard; Owens, S. Michael
2009-01-01
Chronic or excessive (+)-methamphetamine (METH) use often leads to addiction and toxicity to critical organs like the brain. With medical treatment as a goal, a novel single chain variable fragment (scFv) against METH was engineered from anti-METH monoclonal antibody mAb6H4 (IgG, ? light chain, KD = 11 nM) and found to have similar ligand affinity (KD = 10 nM) and specificity as mAb6H4. The anti-METH scFv (scFv6H4) was cloned, expressed in yeast, purified and formulated as a naturally occurring mixture of monomer (~75%) and dimer (~25%). To test the in vivo efficacy of the scFv6H4, male Sprague Dawley rats (n=5) were implanted with 3-day sc osmotic pumps delivering 3.2 mg/kg/day METH. After reaching steady-state METH concentrations, an i.v. dose of scFv6H4 (36.5 mg/kg, equimolar to the METH body burden) was administered along with a [3H]-scFv6H4 tracer. Serum pharmacokinetic (PCKN) analysis of METH and [3H]-scFv6H4 showed that the scFv6H4 caused an immediate 65-fold increase in the METH concentrations and a 12-fold increase in the serum METH area under the concentration-time curve from 0480 min after scFv6H4 administration. The scFv6H4 monomer was quickly cleared or converted to multivalent forms with an apparent t1/2?z of 5.8 min. In contrast, the larger scFv6H4 multivalent forms (dimers, trimers, etc.) showed a much longer t1/2?z (228 min), and the significantly increased METH serum molar concentrations correlated directly with scFv6H4 serum molar concentrations. Considered together these data suggested that the scFv6H4 multimers (and not the monomer) were responsible for the prolonged redistribution of METH into the serum. PMID:18192498
14. Fabrication and Testing of Full-Length Single-Cell Externally Fueled Converters for Thermionic Reactors
SciTech Connect
Schock, Alfred
1995-08-01
Paper presented at the 29th IECEC in Monterey, CA in August 1994. The present paper describes the fabrication and testing of full-length prototypcial converters, both unfueled and fueled, and presents parametric results of electrically heated tests.
15. The Mechanical Transient Process at Asynchronous Motor Oscillating Mode
NASA Astrophysics Data System (ADS)
Antonovi?s, Uldis; Brais, Viesturs; Greivulis, J?nis
2009-01-01
The research object is squirrel-cage asynchronous motor connected to single-phase sinusoidal. There are shown, that by connecting to the stator windings a certain sequence of half-period positive and negative voltage, a motor rotor is rotated, but three times slower than in the three-phase mode. Changing the connecting sequence of positive and negative half-period voltage to stator windings, motor can work in various oscillating modes. It is tested experimentally. The mechanical transient processes had been researched in rotation and oscillating modes.
16. Switching transients in the MFTF yin-yang coils
SciTech Connect
Owen, E.W.; Shimer, D.W.
1982-11-02
This report is a study of the transients caused by the fast dump of large superconducting coils. Theoretical analysis, computer simulation, and actual measurements are used. Theoretical analysis can only be applied to the simplest of models. In the computer simulations two models are used, one in which the coil is divided into ten segments and another in which a single coil is employed. The circuit breaker that interrupts the current to the power supply, causing a fast dump, is represented by a time and current dependent conductance. Actual measurements are limited to measurements made incidental to the coils' performance tests.
17. Performance of the High-Energy Single-Event Effects Test Facility (SEETF) at Michigan State University's National Superconducting Cyclotron Laboratory (NSCL)
NASA Technical Reports Server (NTRS)
Ladbury, R.; Reed, R. A.; Marshall, P. W.; LaBel, K. A.; Anantaraman, R.; Fox, R.; Sanderson, D. P.; Stolz, A.; Yurkon, J.; Zeller, A. F.; Stetson, J. W.
2004-01-01
The performance of Michigan State University's Single-Event Effects Test Facility (SEETF) during its inaugural runs is evaluated. Beam profiles and other diagnostics are presented, and prospects for future development and testing are discussed.
18. Single Group, Pre- and Post-Test Research Designs: Some Methodological Concerns
ERIC Educational Resources Information Center
Marsden, Emma; Torgerson, Carole J.
2012-01-01
This article provides two illustrations of some of the factors that can influence findings from pre- and post-test research designs in evaluation studies, including regression to the mean (RTM), maturation, history and test effects. The first illustration involves a re-analysis of data from a study by Marsden (2004), in which pre-test scores are
19. Functional Interrupts and Destructive Failures from Single Event Effect Testing of Point-Of-Load Devices
NASA Technical Reports Server (NTRS)
Chen, Dakai; Phan, Anthony; Kim, Hak; Swonger, James; Musil, Paul; LaBel, Kenneth
2013-01-01
We show examples of single event functional interrupt and destructive failure in modern POL devices. The increasing complexity and diversity of the design and process introduce hard SEE modes that are triggered by various mechanisms.
20. Simulated Pivot-Shift Testing with Single and Double-Bundle Anterior Cruciate Ligament Reconstructions
Keith L. Markolf; Steven R. Jackson; David R. McAllister; David Geffen
Background: One of the principal rationales for performing a double-bundle reconstruction of the anterior cruciate ligament is the suggestion that it may be superior to a single-bundle reconstruction in restoring a normal pivot-shift sign. The purpose of this study was to measure the abilities of single-bundle and anatomic double-bundle reconstruc- tions to restore normal knee kinematics and graft forces during
1. Transient tachypnea - newborn
MedlinePLUS
TTN; Wet lungs - newborns; Retained fetal lung fluid; Transient RDS; Prolonged transition ... Transient tachypnea is a respiratory disorder seen shortly after delivery in full-term or late preterm babies. ...
2. TIA (Transient Ischemic Attack)
MedlinePLUS
TIA (Transient Ischemic Attack) Updated:Jul 1,2015 Excerpted from Why Rush? , Stroke Connection January/February 2009 (Science update October 2012) While transient ischemic attack (TIA) is often labeled mini-stroke, ...
3. Transient familial hyperbilirubinemia
MedlinePLUS
Transient familial hyperbilirubinemia is a metabolic disorder that is passed down through families. Babies with this disorder ... Transient familial hyperbilirubinemia is an inherited disorder. It occurs when the body does not properly break down ( ...
4. Transient ischemic attack
MedlinePLUS
A transient ischemic attack (TIA) occurs when blood flow to a part of the brain stops for a brief ... prevention of stroke in patients with stroke or transient ischemic attack: a guideline for healthcare professionals from ...
5. High-temperature tensile testing machine for investigation of brittleductile transition behavior of single crystal silicon microstructure
NASA Astrophysics Data System (ADS)
Uesugi, Akio; Yasutomi, Takahiro; Hirai, Yoshikazu; Tsuchiya, Toshiyuki; Tabata, Osamu
2015-06-01
This paper reports development of a high-temperature tensile testing machine and testing of single crystal silicon (SCS) for investigation of the size effect on brittleductile transition temperature (BDTT). Two different-width <110> SCS specimens (120 m long, 5 m thick and 4 or 9 m wide) were tested in a vacuum at the temperature range from room temperature to 600 C. The specimens tested at 500 C and above exhibit slip, which indicated that the micrometer-sized silicon structures have lower BDTT compared to millimeter-sized ones. By investigating the temperature ranges of the slip occurrences among the differently-sized specimens including other researchers reports, we found that the length along slip direction, i.e., thickness, might dominate the BDTT.
6. Columbia University flow instability experimental program: Volume 2. Single tube uniformly heated tests -- Part 2: Uncertainty analysis and data
SciTech Connect
Dougherty, T.; Maciuca, C.; McAssey, E.V. Jr.; Reddy, D.G.; Yang, B.W.
1990-05-01
In June 1988, Savannah River Laboratory requested that the Heat Transfer Research Facility modify the flow excursion program, which had been in progress since November 1987, to include testing of single tubes in vertical down-flow over a range of length to diameter (L/D) ratios of 100 to 500. The impetus for the request was the desire to obtain experimental data as quickly as possible for code development work. In July 1988, HTRF submitted a proposal to SRL indicating that by modifying a facility already under construction the data could be obtained within three to four months. In January 1990, HTFR issued report CU-HTRF-T4, part 1. This report contained the technical discussion of the results from the single tube uniformly heated tests. The present report is part 2 of CU-HTRF-T4 which contains further discussion of the uncertainty analysis and the complete set of data.
7. Potential application of a single-particle aerosol spectrometer for monitoring aerosol size at the DOE filter test facilities
SciTech Connect
Salzman, G.C.; Ettinger, H.J.; Tillery, M.I.; Wheat, L.D.; Grace, W.K.
1982-01-01
At each of the three Department of Energy (DOE) filter test facilities (FTF), a commercial single particle aerosol spectrometer, the LAS-X, was used to demonstrate that the test aerosol produced by each of the Q107 high efficiency particulate air (HEPA) filter test systems was polydisperse with a geometric standard deviation greater than 1.35, and a geometric mean diameter less than 0.2 ..mu..m. These results confirm the work of others that the OWL (mechanical analyzer) is inadequate for assuring that these test aerosols are monodisperse with a mean diameter of 0.3 ..mu..m. Use of the LAS-X for monitoring aerosol size was evaluated. The LAS-X is relatively insensitive to changes in aerosol concentration and refractive index over the range of interest for filter testing. It appears that the LAS-X would provide a better instrument for monitoring aerosol size, and would permit the FTF test operator to adjust the test aerosol to approximate the size characteristics currently recommended for this test.
8. Laboratory and field imaging test results on single-color and dual-band QWIP focal plane arrays
NASA Astrophysics Data System (ADS)
Goldberg, Arnold; Fischer, Theodore; Kennerly, Stephen; Beck, William; Ramirez, Vincent; Garner, Ken
2001-06-01
We report on recent laboratory and field measurements on quantum well infrared photodetector (QWIP) focal plane arrays (FPAs). The results of laboratory measurements of imaging performance such as noise-equivalent temperature difference (NE ?T), minimum resolvable temperature, conversion efficiency, uniformity of response and dark current and their dependence on operating temperature are presented on large format (640480 pixels) single-color long-wavelength infrared (LWIR) and dual-band (256256 pixels) mid-wavelength infrared (MWIR)/LWIR arrays. We found that under optimum operating conditions (65 K and 1 V bias), the NE ?T of the LWIR FPA was approximately 30 mK and was limited by the optics and noise from the closed-cycle cooler. We will show field imagery of military targets taken with this FPA. In addition, field imagery taken with the LWIR QWIP camera of a large-transient event will be compared with that taken with an InSb MWIR camera. We will also show imagery of a recent total eclipse of the moon. We will also present laboratory results on a simultaneously integrating, pixel-registered dual-band FPA showing excellent operability and response uniformity with NE ?T of approximately 30 mK in both bands ( T=60 K). The dual-band FPA was also taken to the field and we will present imagery of various targets acquired with this FPA.
9. Experimental study on the material dynamic fracture properties by Instrumented Charpy Impact test with single specimen method
F. Jian; D. Fulian; W. Chengzhong
2003-01-01
With the determination of load-time curve recorded by Amsler\\/Roell RKP 450 Instrumented Charpy Impact test and based on the Newton's Second Law, Impact character of a single standard V-notch specimen of X70 pipeline steel under the low temperature -70 ^{circ}C was investigated by studying the impact energy distribution. It was revealed that maximum load point (Fm point) was not exact
10. Using energy balances for processing the results from tests of a single-shaft combined-cycle power plant
NASA Astrophysics Data System (ADS)
Ol'khovskii, G. G.
2012-09-01
Application of the balance method for dividing the overall power output produced by a single-shaft combined-cycle power plant between the steam turbine and gas turbine unit is considered. It is shown that the method can be used for obtaining trustworthy results of thermal tests. The effect of air flowrate taken for gas turbine cooling purposes on the gas turbine unit parameters and indicators is estimated.
11. Measurement of interfacial shear strength of carbon fibre\\/epoxy composites using a single fibre pull-out test
Shiqiang Deng; Lin Ye; Yiu-Wing Mai
1998-01-01
Single fiber pull-out tests were conducted for G34-700\\/ Araldite-F, T700S\\/Araldite-F and T800H\\/Araldite-F model composites using an improved experimental set-up to evaluate the interfacial shear strength (IFSS). The modified method made it possible to reduce the formation of resin meniscus and to accurately define the embedded fibre length, and it also provided a practical approach to conveniently estimate the IFSS for
12. Single-pass continuous-flow leach test of PNL 76-68 glass: some selected Bead Leach I results
Coles
1981-01-01
A single-pass continuous-flow leach test of PNL 76-68 glass beads (7 mm dia) was concluded after 420 days of uninterrupted operation. Variables included in the experimental matrix were flow-rate, leachant composition, and temperature. Analysis was conducted on all leachate samples for ²³⁷Np and ²³⁹Pu as well as a number of nonradioactive elements. Results indicated that flow-rate and leachant systematically affected
13. Use of a single lap shear test to characterize composite-to-concrete or composite-to-steel bonded interfaces
Sylvain Chataigner; Jean-Francois Caron; Karim Benzarti; Marc Quiertant; Christophe Aubagnac
2011-01-01
Adhesively bonded composite reinforcements are increasingly being used for civil engineering structures. For an adequate use of such a technique, a better knowledge is needed regarding the stress transfer mechanisms involved in polymer joints. This article introduces a single lap shear test for the characterization of the composite-to-concrete or composite-to-steel bonded assemblies. In the first part, an extensive description of
14. 42 CFR 84.1144 - Silica dust test for dust, fume, and mist respirators; single-use or reusable filters; minimum...
Code of Federal Regulations, 2013 CFR
2013-10-01
...for dust, fume, and mist respirators; single-use or reusable filters; minimum requirements...for dust, fume, and mist respirators; single-use or reusable filters; minimum requirements...Three non-powered respirators with single-use filters will be tested for...
15. 42 CFR 84.1144 - Silica dust test for dust, fume, and mist respirators; single-use or reusable filters; minimum...
Code of Federal Regulations, 2014 CFR
2014-10-01
...for dust, fume, and mist respirators; single-use or reusable filters; minimum requirements...for dust, fume, and mist respirators; single-use or reusable filters; minimum requirements...Three non-powered respirators with single-use filters will be tested for...
16. 42 CFR 84.1144 - Silica dust test for dust, fume, and mist respirators; single-use or reusable filters; minimum...
Code of Federal Regulations, 2012 CFR
2012-10-01
...for dust, fume, and mist respirators; single-use or reusable filters; minimum requirements...for dust, fume, and mist respirators; single-use or reusable filters; minimum requirements...Three non-powered respirators with single-use filters will be tested for...
17. Perturbations for transient acceleration
SciTech Connect
Vargas, Cristofher Zuiga; Zimdahl, Winfried [Universidade Federal do Esprito Santo, Departamento de Fsica, Av. Fernando Ferrari, 514, Campus de Goiabeiras, CEP 29075-910, Vitria, Esprito Santo (Brazil); Hiplito-Ricaldi, Wiliam S., E-mail: [email protected], E-mail: [email protected], E-mail: [email protected] [Universidade Federal do Esprito Santo, Departamento de Cincias Naturais, Grupo de Fsica Terica, Rodovia BR 101 Norte, km 60, Campus de So Mateus, CEP 29932-540, So Mateus, Esprito Santo (Brazil)
2012-04-01
According to the standard ?CDM model, the accelerated expansion of the Universe will go on forever. Motivated by recent observational results, we explore the possibility of a finite phase of acceleration which asymptotically approaches another period of decelerated expansion. Extending an earlier study on a corresponding homogeneous and isotropic dynamics, in which interactions between dark matter and dark energy are crucial, the present paper also investigates the dynamics of the matter perturbations both on the Newtonian and General Relativistic (GR) levels and quantifies the potential relevance of perturbations of the dark-energy component. In the background, the model is tested against the Supernova type Ia (SNIa) data of the Constitution set and on the perturbative level against growth rate data, among them those of the WiggleZ survey, and the data of the 2dFGRS project. Our results indicate that a transient phase of accelerated expansion is not excluded by current observations.
18. Ris-R-1483(EN) Testing procedure for the single fiber
E-print Network
fragmentation test as conducted at the materials research department (AFM) at Ris. The equipment and specimen in the critical fracture length for the fiber and fracture characteristics. Print: Pitney Bowes Management Test equipment 11 4.1 Tensile tester 11 4.2 Fragmentation equipment 11 4.3 Fragmentation under
19. In situ evaluation of solute retardation using single-well pushpull tests
M. H Schroth; J. D Istok; R Haggerty
2000-01-01
More efficient methods are needed for the in situ evaluation of solute sorption to aquifer sediments. The objective of this study was to develop a simplified method for estimating retardation factors for injected solutes from pushpull test extraction phase breakthrough curves (BTCs). Sensitivity analyses based on numerical simulations were used to evaluate the method performance for a variety of test
20. Randomization Tests for Systematic Single-Case Designs Are Not Always Appropriate
ERIC Educational Resources Information Center
Sierra, Vicenta; Solanas, Antonio; Quera, Vicenc
2005-01-01
The authors used a Monte Carlo simulation to examine how the violation of the exchangeability assumption affects empirical Type I error rates of the LMH randomization test (J. R. Levin, L. A. Marascuilo, & L. J. Hubert, 1978). Simulation results showed that the LMH test is not always an appropriate technique for analyzing systematic designs when
1. DREDGED MATERIAL EFFECTS ASSESSMENT: SINGLE-SPECIES TOXICITY/BIOACCUMULATION AND MACROBENTHOS COLONIZATION TESTS
EPA Science Inventory
Toxicity tests and bioaccumulation tests conducted according to methods established by the U.S. Environmental Protection Agency/Corps of Engineers in 1977 have been used to evaluate potential environmental impacts of ocean disposal of dredged materials. ur objective was to compar...
2. Energy absorbed in breakage of single particles in drop weight testing
L. M. Tavares
1999-01-01
Drop weight tests are a useful tool to determine energy-size reduction relationships for breakage of particulate materials. Their use in modeling and simulation of size reduction operations has increased significantly in recent years. The main limitation of the classical drop weight test lies in the fact that it does not allow the direct measurement of the fraction of the input
3. A Single Adrenocorticotropic Hormone Stimulation Test Does Not Reveal Adrenal Insufficiency in Septic Shock
Pekka Loisa; Ari Uusaro; Esko Ruokonen
2005-01-01
The diagnosis of adrenocortical insufficiency in criti- cally ill patients is complex. The adrenocorticotropic hormone (ACTH) stimulation test is a widely accepted method for assessing the adequacy of adrenal function in intensive care units, but it is possible that there may be wide variations in responses to the test over a short period of time. In this prospective study, we
4. Single Tube Test Program Demand Curve Data Tables. Columbia University Flow Instability Experimental Program, Volume 9
SciTech Connect
Coutts, D.A.
1993-09-01
This report is one of a series of reports which document the flow instability testing conducted by Columbia University during 1989, through 1992. This testing was completed as part of AX1811457. Data files were transmitted to SRS in a DOS compatible format. This report volume provides a hardcopy version of the electronic media data files.
5. Crack detection in single-crystalline silicon wafers using impact testing
C. Hilmersson; D. P. Hess; W. Dallas; S. Ostapenko
2008-01-01
This paper presents acoustic measurements obtained by mechanically exciting vibratory modes in single-crystalline silicon wafers with hairline periphery cracks of different type and location. The data presented shows a dependence of natural frequencies, peak amplitudes and damping levels of four audio vibration modes in the frequency range up to 1000Hz on crack type and crack location. Data from defective wafers
6. Test results of single-event effects conducted by the Jet Propulsion Laboratory
F. Trom; Tetsuo F. Miyahira
2005-01-01
This paper reports recent single-event effects results for a variety of microelectronic devices that include ADC, DAC, DDS, MOSFET driver, analog switch, oscillator, and zero delay buffer. The data was collected to evaluate these devices for possible use in NASA spacecraft. Six of ten devices under study were sensitive to SEL, and the latchup was destructive.
7. Comparison between single and combined post-treatment with S-Methyl-N,N-diethylthiolcarbamate sulfoxide and taurine following transient focal cerebral ischemia in rat brain.
PubMed
Gharibani, P; Modi, J; Menzie, J; Alexandrescu, A; Ma, Z; Tao, R; Prentice, H; Wu, J-Y
2015-08-01
We have recently reported on the efficacy of an N-methyl-d-aspartate (NMDA) receptor partial antagonist, S-Methyl-N,N-diethylthiolcarbamate sulfoxide (DETC-MeSO), in improving outcome following stroke, including reduced infarct size and calcium influx, suppressing the endoplasmic reticulum (ER) stress-induced apoptosis as well as improving behavioral outcome. DETC-MeSO was shown to suppress the protein kinase R-like endoplasmic reticulum kinase (PERK) pathway, one of the major ER stress pathways. Several studies including ours have provided evidence that taurine also has neuroprotective effects through reducing apoptosis and inhibiting activating transcription factor 6 (ATF6) and inositol requiring enzyme 1 (IRE-1) pathways. We hypothesized that a combined treatment with DETC-MeSO and taurine would ameliorate ischemia-induced brain injury by inhibiting all three ER stress pathways. Twenty four hours following reperfusion of a 2-h ischemic stroke, rats received either 0.56-mg/kg DETC-MeSO or 40-mg/kg of taurine, either alone or in combination, subcutaneously for 4days. Our study showed that combined DETC-MeSO and taurine, but not DETC-MeSO alone at the dose used, greatly reduced the infarct size, improved performance on the neuro-score test and attenuated proteolysis of ?II-spectrin. Meanwhile, the level of the pro-apoptotic protein, Bax, declined and the anti-apoptotic protein, B-cell lymphoma 2 (BCL-2), expression was markedly increased. Combination therapy decreased both caspase-12 and caspase-3 activation by preventing the release of Cytochrome-c from mitochondria, indicating attenuation of apoptosis in ischemic infarct. Glucose-regulated protein (GRP)78 as a marker of the unfolded protein response decreased and levels of the key ER stress protein markers p-PERK-ATF4, p-eIF2? and cleaved-ATF-6 were found to significantly decline. NeuN expression levels indicated that more neurons were protected in the presence of DETC-MeSO and taurine. We also showed that combined treatment can prevent gliosis and increase p-AKT a pro-survival marker in the penumbra. Therefore, we conclude that combined treatment with both DETC-MeSO and taurine synergistically inhibits all three ER stress pathways and apoptosis and therefore can be a novel and effective treatment after ischemic stroke. PMID:26022360
8. Aligned and suspended fiber force probes for drug testing at single cell resolution.
PubMed
Sharma, Puja; Kim, AhRam; Gill, Amritpal; Wang, Ji; Sheets, Kevin; Behkam, Bahareh; Nain, Amrinder S
2014-12-01
The role of physical forces in disease onset and progression is widely accepted and this knowledge presents an alternative route to investigating disease models. Recently, numerous force measurement techniques have been developed to probe single and multi-cell behavior. While these methods have yielded fundamental insights, they are yet unable to capture the fibrous extra-cellular matrix biophysical interactions, involving parameters of curvature, structural stiffness (N m(-1)), alignment and hierarchy, which have been shown to play key roles in disease and developmental biology. Using a highly aggressive glioma model (DBTRG-05MG), we present a platform technology to quantify single cell force modulation (both inside-out and outside-in) with and without the presence of a cytoskeleton altering drug (cytochalasin D) using suspended and aligned fiber networks (nanonets) beginning to represent the aligned glioma environment. The nanonets fused in crisscross patterns were manufactured using the non-electrospinning spinneret based tunable engineering parameters technique. We demonstrate the ability to measure contractile single cell forces exerted by glioma cells attached to and migrating along the fiber axis (inside-out). This is followed by a study of force response of glioma cells attached to two parallel fibers using a probe deflecting the leading fiber (outside-in). The forces are calculated using beam deflection within the elastic limit. Our data shows that cytochalasin D compromises the spreading area of single glioma cells, eventually decreasing their 'inside-out' contractile forces, and 'outside-in' force response to external strain. Most notably, for the first time, we demonstrate the feasibility of using physiologically relevant aligned fiber networks as ultra-sensitive force (?nanoNewtons) probes for investigating drug response and efficacy in disease models at the single cell resolution. PMID:25264874
9. Merging single-well and inter-well tracer tests into one forced-gradient dipole test, at the Heletz site within the MUSTANG project
NASA Astrophysics Data System (ADS)
Behrens, Horst; Ghergut, Julia; Bensabat, Jac; Niemi, Auli; Licha, Tobias; Ptak, Thomas; Sauter, Martin
2014-05-01
The Heletz site[1] in Israel was chosen for conducting a CO2 transport experiment within the MUSTANG project[2], whose aim is to demonstrate and validate leading-edge techniques for CCS site characterization, process monitoring and risk assessment. The major CO2 injection experiment at Heletz was supposed to be preceded and accompanied by a sequence of single-well 'push-then-pull' (SW) and inter-well (IW) tracer tests, aimed at characterizing transport properties of the storage formation, in accordance to a number of general and specific principles[3],[4]. - Instead of the rather luxurious {SW1, IW1, SW2, IW2} test sequence described in our previous work[5], we now propose a drastically economized tracer test concept, which lets the sampling stages of SW and IW tests merge into a single fluid production stage, and relies on a forced-gradient dipole flow field at any time of the overall test. Besides cost reduction, this economized design also improves on operational aspects, as well as on issues of parameter ambiguity and of scale disparity between SW and IW flow fields: (i) the new design renders SW test results more representative for the aquifer sector ('angle') actually interrogated by the IW dipole test; (ii) the new design saves time and costs on the SW test (fluid sampling for SW 'pull' now being conducted simultaneously with IW-related sampling and monitoring), while allowing for a considerably longer duration of SW 'pull' signals than had originally been intended, whose late-time tailings help improve the quantification of non-advective processes and parameters, which are of great relevance to mid- and long-term trapping mechanisms ('residual trapping', 'mineral trapping'); (iii) the quasi-simultaneous execution of fluid injection/production for the IW and SW tests considerably reduces the overall hydraulic imbalance that was originally associated with the SW test, thus preventing formation damage and supporting hydrogeomechanical stability; (iv) the new design reduces the imbalance between injected and produced fluid volumes at any time to a minimum, thus eliminating the need for large-capacity tanks (and water supply) to provide 'push' fluid for injection and to store 'pull' fluid during production within the SW test (saving on costs again). Advantages and drawbacks of this modified tracer test concept w. r. to parameter sensitivity and scale representativity are further analyzed by means of numerical simulations of tracer transport in the layered Heletz aquifer (using FEOW) alongside with closed-form approximations to tracer signals. References: [1] www.co2mustang.eu/Heletz.aspx [2] www.co2mustang.eu/ [3] Behrens H, Ghergut I, Sauter M (2010) Tracer properties, and tracer test results, part 3: modification to Shook's flow-storage diagram. Stanford Geothermal Prog Tech Reports, SGP-TR-188 [4] Ghergut I, Behrens H, Maier F, Karmakar S, Sauter M (2011) A note on 'heat exchange areas' as a target parameter for tracer SWIW tests. Stanford Geothermal Prog Tech Reports, SGP-TR-191 [5] presentations.copernicus.org/EGU2012-13549_presentation.pdf and presentations.copernicus.org/EGU2013-3683_presentation.pdf Acknowledgements: Heletz hydrostratigraphy data were provided by the MUSTANG project teams[1],[2], this project being funded by the EU under FP7 (grant no. 227286). Tracer transport modeling for IW and SW tests in layered reservoirs was conducted within the 'gebo' project ('Geothermal Energy and High-Performance Drilling', www.gebo-nds.de), funded by the Lower-Saxonian government and by Baker Hughes (Celle), Germany.
10. A multianalyte PCR blood test outperforms single analyte ELISAs (chromogranin A, pancreastatin, neurokinin A) for neuroendocrine tumor detection.
PubMed
Modlin, Irvin M; Drozdov, Ignat; Alaimo, Daniele; Callahan, Stephen; Teixiera, Nancy; Bodei, Lisa; Kidd, Mark
2014-08-01
A critical requirement in neuroendocrine tumor (NET) management is a sensitive, specific and reproducible blood biomarker test. We evaluated a PCR-based 51 transcript signature (NETest) and compared it to chromogranin A (CgA), pancreastatin (PST) and neurokinin A (NKA). The multigene signature was evaluated in two groups: i) a validation set of 40 NETs and controls and ii) a prospectively collected group of NETs (n=41, 61% small intestinal, 50% metastatic, 44% currently treated and 41 age-sex matched controls). Samples were analyzed by a two-step PCR (51 marker genes) protocol and ELISAs for CgA, PST and NKA. Sensitivity comparisons included ?(2), non-parametric measurements, ROC curves and predictive feature importance (PFAI) analyses. NETest identified 38 of 41 NETs. Performance metrics were: sensitivity 92.8%, specificity 92.8%, positive predictive value 92.8% and negative predictive value 92.8%. Single analyte ELISA metrics were: CgA 76, 59, 65, and 71%; PST 63, 56, 59, and 61% and NKA 39, 93, 84, and 60%. The AUCs (ROC analysis) were: NETest: 0.960.025, CgA: 0.670.06, PST 0.560.06, NKA: 0.660.06. NETest significantly outperformed single analyte tests (area differences: 0.284-0.403, Z-statistic 4.85-5.9, P<0.0001). PFAI analysis determined NETest had most value (69%) in diagnosis (CgA (13%), PST (9%), and NKA (9%)). Test data were consistent with the validation set (NETest >95% sensitivity and specificity, AUC =0.98 vs single analytes: 59-67% sensitivity, AUCs: 0.58-0.63). The NETest is significantly more sensitive and efficient (>93%) than single analyte assays (CgA, PST or NKA) in NET diagnosis. Blood-based multigene analytic measurement will facilitate early detection of disease recurrence and can predict therapeutic efficacy. PMID:25015994
11. Single Event Effects Testing For Low Earth Orbit Missions with Neutrons
NASA Technical Reports Server (NTRS)
Reddell, Brandon; O'Neill, Pat; Bailey, Chuck; Nguyen, Kyson
2015-01-01
Neutrons can effectively be used to screen electronic parts intended to be used in Low Earth Orbit. This paper compares neutron with proton environments in spacecraft and discusses recent comparison testing.
12. Model refinement using transient response
SciTech Connect
Dohrmann, C.R.; Carne, T.G.
1997-12-01
A method is presented for estimating uncertain or unknown parameters in a mathematical model using measurements of transient response. The method is based on a least squares formulation in which the differences between the model and test-based responses are minimized. An application of the method is presented for a nonlinear structural dynamic system. The method is also applied to a model of the Department of Energy armored tractor trailer. For the subject problem, the transient response was generated by driving the vehicle over a bump of prescribed shape and size. Results from the analysis and inspection of the test data revealed that a linear model of the vehicle`s suspension is not adequate to accurately predict the response caused by the bump.
13. Single event upset test structures for digital CMOS application specific integrated circuits
SciTech Connect
Baze, M.P.; Bartholet, W.G.; Braatz, J.C.; Dao, T.A. (Boeing Defense and Space Group, Seattle, WA (United States))
1993-12-01
An approach has been developed for the design and utilization of SEU test structures for digital CMOS ASICs. This approach minimizes the number of test structures required by categorizing ASIC library cells according to their SEU response and designing a structure to characterize each response for each category. Critical SEU response parameters extracted from these structures are used to evaluate the SEU hardness of ASIC libraries and predict the hardness of ASIC chips.
14. Insight from simulations of single-well injection-withdrawal tracer tests on simple and complex fractures
SciTech Connect
Tsang, C.-F.; Doughty, C.
2009-08-06
The single-well injection withdrawal (SWIW) test, a tracer test utilizing only one well, is proposed as a useful contribution to site characterization of fractured rock, as well as providing parameters relevant to tracer diffusion and sorption. The usual conceptual model of flow and solute transport through fractured rock with low matrix permeability involves solute advection and dispersion through a fracture network coupled with diffusion and sorption into the surrounding rock matrix. Unlike two-well tracer tests, results of SWIW tests are ideally independent of advective heterogeneity, channeling and flow dimension, and, instead, focus on diffusive and sorptive characteristics of tracer (solute) transport. Thus, they can be used specifically to study such characteristics and evaluate the diffusive parameters associated with tracer transport through fractured media. We conduct simulations of SWIW tests on simple and complex fracture models, the latter being defined as having two subfractures with altered rock blocks in between and gouge material in their apertures. Using parameters from the Aspo site in Sweden, we calculate and study SWIW tracer breakthrough curves (BTCs) from a test involving four days of injection and then withdrawal. By examining the peak concentration C{sub pk} of the SWIW BTCs for a variety of parameters, we confirm that C{sub pk} is largely insensitive to the fracture advective flow properties, in particular to permeability heterogeneity over the fracture plane or to subdividing the flow into two subfractures in the third dimension orthogonal to the fracture plane. The peak arrival time t{sub pk} is not a function of fracture or rock properties, but is controlled by the time schedule of the SWIW test. The study shows that the SWIW test is useful for the study of tracer diffusion-sorption processes, including the effect of the so-called flow-wetted surface (FWS) of the fracture. Calculations with schematic models with different FWS values are conducted and the possibility of direct in situ measurement of FWS with SWIW tests is demonstrated.
15. Low-speed wind-tunnel tests of single- and counter-rotation propellers
NASA Technical Reports Server (NTRS)
Dunham, D. M.; Gentry, G. L., Jr.; Coe, P. L., Jr.
1986-01-01
A low-speed (Mach 0 to 0.3) wind-tunnel investigation was conducted to determine the basic performance, force and moment characteristics, and flow-field velocities of single- and counter-rotation propellers. Compared with the eight-blade single-rotation propeller, a four- by four- (4 x 4) blade counter-rotation propeller with the same blade design produced substantially higher thrust coefficients for the same blade angles and advance ratios. The results further indicated that ingestion of the wake from a supporting pylon for a pusher configuration produced no significant change in the propeller thrust performance for either the single- or counter-rotation propellers. A two-component laser velocimeter (LV) system was used to make detailed measurements of the propeller flow fields. Results show increasing slipstream velocities with increasing blade angle and decreasing advance ratio. Flow-field measurements for the counter-rotation propeller show that the rear propeller turned the flow in the opposite direction from the front propeller and, therefore, could eliminate the swirl component of velocity, as would be expected.
16. Measurement of internal and external mixtures of test aerosols with a new Single Particle Aerosol Mass Spectrometer
NASA Astrophysics Data System (ADS)
Wonaschtz, Anna; Hitzenberger, Regina
2015-04-01
The mixing state of atmospheric aerosol particles is a very important property affecting processes such as CCN activation and scattering and absorption of light by the particles, but is challenging to determine. A new Single Particle Aerosol Mass Spectrometer (LAAPTOF, AeroMegt GmbH) was tested with regards to its capability of measuring internal and external mixture of aerosols using laboratory generated particles. To create the external mixture, solutions of three different salts in deionized water, and a suspension of carbon black (Cabot Corporation) in a mixture of isopropanol and water were nebulized and individually dried, before being passed into a small mixing chamber. To create the internal mixture, equal parts of each solution/suspension were mixed, fed into a single nebulizer, nebulized and dried. The LAAPTOF sampled from the mixing chamber and recorded mass spectra of individual particles. The analysis shows a heterogeneous ensemble of single particle spectra for the external mixture, and a homogeneous ensemble of spectra for the internal mixture. The ability of a fuzzy clustering algorithm to resolve the difference between the two mixing states was also tested.
17. Post-test comparison of thermal-hydrologic measurements and numerical predictions for the in situ single heater test, Yucca Mountain, Nevada
SciTech Connect
Ballard, S.; Francis, N.D.; Sobolik, S.R.; Finley, R.E.
1998-06-01
The Single Heater Test (SHT) is a sixteen-month-long heating and cooling experiment begun in August, 1996, located underground within the unsaturated zone near the potential geologic repository at Yucca Mountain, Nevada. During the 9 month heating phase of the test, roughly 15 m{sup 3} of rock were raised to temperatures exceeding 100 C. In this paper, temperatures measured in sealed boreholes surrounding the heater are compared to temperatures predicted by 3D thermal-hydrologic calculations performed with a finite difference code. Three separate model runs using different values of bulk rock permeability (4 microdarcy to 5.2 darcy) yielded significantly different predicted temperatures and temperature distributions. All the models differ from the data, suggesting that to accurately model the thermal-hydrologic behavior of the SHT, the Equivalent Continuum Model (ECM), the conceptual basis for dealing with the fractured porous medium in the numerical predictions, should be discarded in favor of more sophisticated approaches.
18. Waste characterization plan for the Hanford Site single-shell tanks. Appendix I, Test plan for sampling and analysis of ten single-shell tanks
SciTech Connect
Hill, J.G.; Winters, W.I.; Simpson, B.C. [Westinghouse Hanford Co., Richland, WA (United States); Buck, J.W.; Chamberlain, P.J.; Hunter, V.L. [Pacific Northwest Lab., Richland, WA (United States)
1991-09-01
This appendix describes the sampling and analysis of the next ten single-shell tanks (SST) following the successful of SSTs B-201 and B-202. SST T-203 shall not be core sampled sequentially after B-201 and B-202, as originally planned, because this tank would not have provided information on tank safety issues and it contains an identical waste type as the previous two SSTs. Therefore, sampling and analysis of T-203 at the present time was considered repetitious and not an efficient utilization of the limited available resources. This test plan will outline methodology for characterization of the next ten SSTs, summarize lessons learned in the laboratory during Phase IA/IB, identify criteria for tank selection, and detail the analysis to be performed during the characterization of each tank. The sampling, analysis, and data collection, detailed by the this test plan, are being performed to support the final SST closure date of 2,018 identified in the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement).
19. EBR-II high-ramp transients under computer control
SciTech Connect
Forrester, R.J.; Larson, H.A.; Christensen, L.J.; Booty, W.F.; Dean, E.M.
1983-01-01
During reactor run 122, EBR-II was subjected to 13 computer-controlled overpower transients at ramps of 4 MWt/s to qualify the facility and fuel for transient testing of LMFBR oxide fuels as part of the EBR-II operational-reliability-testing (ORT) program. A computer-controlled automatic control-rod drive system (ACRDS), designed by EBR-II personnel, permitted automatic control on demand power during the transients.
20. Test for determining a subdiffusive model in ergodic systems from single trajectories.
PubMed
Meroz, Yasmine; Sokolov, Igor M; Klafter, Joseph
2013-03-01
Experiments on particle motion show that it is often subdiffusive. This subdiffusion may be due to trapping, percolationlike structures, or viscoelastic behavior of the medium. While the models based on trapping (leading to continuous-time random walks) can easily be distinguished from the rest by testing their nonergodicity, the latter two cases are harder to distinguish. We propose a statistical test for distinguishing between these two based on the space-filling properties of trajectories, and prove its feasibility and specificity using synthetic data. We moreover present a flow chart for making a decision on a type of subdiffusion for a broader class of models. PMID:23496698
1. In Situ Tensile Testing of Single Crystal Molybdenum Alloy Fibers with Various Dislocation Densities in a Scanning Electron Microscope
SciTech Connect
George, Easo P [ORNL; Johanns, K. [University of Tennessee, Knoxville (UTK); Sedlmayr, A. [Karlsruhe Institute of Technology, Karlsruhe, Germany; Phani, P. Sudharshan [University of Tennessee, Knoxville (UTK); Monig, R. [Karlsruhe Institute of Technology, Karlsruhe, Germany; Kraft, O. [Karlsruhe Institute of Technology, Karlsruhe, Germany; Pharr, George M [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL)
2012-01-01
In-situ tensile tests have been performed in a dual beam focused ion beam and scanning electron microscope on as-grown and prestrained single-crystal molybdenum-alloy (Mo-alloy) fibers. The fibers had approximately square cross sections with submicron edge lengths and gauge lengths in the range of 9-41 {mu}m. In contrast to previously observed yield strengths near the theoretical strength of 10 GPa in compression tests of {approx}1-3-{mu}m long pillars made from similar Mo-alloy single crystals, a wide scatter of yield strengths between 1 and 10 GPa was observed in the as-grown fibers tested in tension. Deformation was dominated by inhomogeneous plastic events, sometimes including the formation of Lueders bands. In contrast, highly prestrained fibers exhibited stable plastic flow, significantly lower yield strengths of {approx}1 GPa, and stress-strain behavior very similar to that in compression. A simple, statistical model incorporating the measured dislocation densities is developed to explain why the tension and compression results for the as-grown fibers are different.
2. Testing of polyimide second-stage rod seals for single-state applications in advanced aircraft hydraulic systems
NASA Technical Reports Server (NTRS)
Waterman, A. W.
1977-01-01
Machined polyimide second-stage rod seals were evaluated to determine their suitability for single-stage applications where full system pressure acts on the upstream side of the seal. The 6.35-cm (2.5-in.) K-section seal was tested in impulse screening tests where peak pressure was increased in 3.448-MPa (500-psi) increments each 20,000 cycles. Seal failure occurred at 37.92 MPa (5,500 psi), indicating a potential for acceptability in a 27.58-MPa (4,000-psi) system. Static pressurization for 600 sec at pressures in excess of 10.34 MPa (1,500 psi) revealed structural inadequacy of the seal cross section to resist fracture and extrusion. Endurance testing showed the seals capable of at least 65,000 1.27-cm (0.5-in.) cycles at 450 K (350 F) without leakage. It was concluded that the second-stage seals were proven to be exceptional in the 1.379-MPa (200-psi) applications for which they were designed, but polyimide material properties are not adequate for use in this design at pressure loading equivalent to that present in single-stage applications.
3. Testing the validity of the single-spin approximation in inspiral-merger-ringdown waveforms
E-print Network
Michael Prrer; Mark Hannam; P. Ajith; Sascha Husa
2013-06-10
Gravitational-wave signals from black-hole binaries with non-precessing spins are described by four parameters -- each black hole's mass and spin. It has been shown that the dominant spin effects can be modeled by a \\emph{single} spin parameter, leading to the development of several \\emph{three-parameter} waveform models. Previous studies indicate that these models should be adequate for gravitational-wave detection. In this paper we focus on the systematic biases that would result from using them to estimate binary parameters, and consider a one-parameter family of configurations at one choice of mass ratio and effective single spin. We find that for low-mass binaries within that family of configurations, where the observable waveform is dominated by the inspiral, the systematic bias in all physical parameters is smaller than the parameter uncertainty due to degeneracies between the mass ratio and the spins, at least up to signal-to-noise ratios (SNRs) of 50. For higher-mass binaries, where the merger and ringdown make a greater contribution to the observed signal, the bias in the mass ratio is comparable to its uncertainty at SNRs of only $\\sim$30, and the bias in the measurement of the total spin is \\emph{larger} than the uncertainty defined by the 90% confidence region even at an SNR of only 10. Although this bias may be mitigated in future models by a better choice of single-effective-spin parameter, these results suggest that it may be possible to accurately measure \\emph{both} black-hole spins in intermediate-mass binaries.
4. Exponential speed-up with a single bit of quantum information: Testing the quantum butterfly effect
E-print Network
David Poulin; Robin Blume-Kohout; Raymond Laflamme; Harold Ollivier
2003-10-06
We present an efficient quantum algorithm to measure the average fidelity decay of a quantum map under perturbation using a single bit of quantum information. Our algorithm scales only as the complexity of the map under investigation, so for those maps admitting an efficient gate decomposition, it provides an exponential speed up over known classical procedures. Fidelity decay is important in the study of complex dynamical systems, where it is conjectured to be a signature of quantum chaos. Our result also illustrates the role of chaos in the process of decoherence.
5. Total dose, displacement damage, and single event effects in the radiation hardened CMOS APS HAS2
Dirk van Aken; Dominique Herv; Matthieu Beaumel
2009-01-01
Experimental results of several radiation test campaigns performed on the HAS2 CMOS imager are presented. The radiation testing includes Cobalt-60 total ionizing dose at low and high dose rate, proton and electron displacement damage, proton induced single event transient, and heavy ion single event effect. HAS2 electro-optical performances have been characterized during irradiation at low and room temperature, and after
6. High speed single transient microwave spectrum analyzer
SciTech Connect
Stokes, J.; Ogle, J.; Looney, L.; Gallegos, C.; Anaya, R.; Lilijestrand, R.
1989-01-01
Recent experiments have required the measurement of short pulse high bandwidth microwave spectra. To meet this need we built a GHz-bandwidth acousto-optic spectrum analyzer. The hardware includes a HeNe laser, collimating optics, Brag cell, steak camera, microchannel plate intensifier and film cassette. The frequency range measured was 350--2000 MHz with a dynamic range greater than 20 dB. Pulse widths from 10 ns were measured with this system. 4 figs.
7. Single-Locus Tests of Microsatellite Evolution: Multi-Step Mutations and Constraints on Allele Size
E-print Network
Nielsen, Rasmus
and population genetics (e.g., Bruford and Wayne, 1993). The advantage of microsatellites over other nuclear loci, Irvine, California 92697; and Department of Population Biology, University of Copenhagen of constraints on the repeat number have only very limited power. The tests were applied to population data
8. STATUS OF HIGH POWER TESTS OF NORMAL CONDUCTING SINGLE-CELL STANDING WAVE STRUCTURES
E-print Network
Istituto Nazionale di Fisica Nucleare (INFN)
- tures of the same geometry and material, and the break- down rate dependence on peak magnetic fields materials were exposed to pulse rf magnetic fields, with es- timated pulse temperature rise of up to 110 C the main results from tests of seven structures made from hard copper, soft- copper alloys and hard
9. A single sample GnRHa stimulation test in the diagnosis of precocious puberty
Technology Transfer Automated Retrieval System (TEKTRAN)
Gonadotropin-releasing hormone (GnRH) has been the standard test for diagnosing central precocious puberty. Because GnRH is no longer available, GnRH analogues (GnRHa) are now used. Random LH concentration, measured by the third-generation immunochemiluminometric assay, is a useful screening tool ...
10. Environmental assessment: Single-stage rocket technology DC-X test program
SciTech Connect
Not Available
1992-06-01
The National Environmental Policy Act (NEPA), the Council on Environmental Quality (CEQ) regulations implementing NEPA (40 CFR Parts 1500-1508), and U.S. Department of Defense (DoD) Directive 6050.1 direct that decision-makers take into account environmental consequences when authorizing or approving major federal actions. This environmental assessment (EA) evaluates the environmental consequences of conducting activities for the SSRT test program. The purpose of the proposed action is to provide SDIO with a suborbital, recoverable rocket (SRR) capable of lifting up to 3,000 pounds of payload to an altitude of 1.5 million feet; returning to the launch site for a precise soft landing; with the capability to launch for another mission within three to seven days. To support these requirements, the proposed action involves validation and testing of a DC-X vehicle. Component assembly of the vehicle will take place at Scaled Composites, Inc., Mojave, CA; Chicago Bridge and Iron, Cordova, AL; Pratt and Whitney, West Palm Beach, FL, Aerojet, Sacramento, CA; and McDonnell Douglas Space Systems Company, Beach, CA. Static test firing activities will occur at NASA/White Sands Test Facility Huntington (WSTF), WSMR, New Mexico, and launch activities will occur at White Sands Space Harbor (WSSH), WSMR, New Mexico. No significant impacts are anticipated to the environment at the engineering contractor facilities, NASA/WSTF, or WSSH.
11. Ultrashort pulsed laser tools for testing of semiconductor elements hardness to single event effects, caused by cosmic heavy charged particles
NASA Astrophysics Data System (ADS)
Gordienko, Alexandra V.; Mavritskii, Oleg B.; Egorov, Andrey N.; Pechenkin, Alexander A.; Savchenkov, Dmitriy V.
2015-03-01
The installations for laser testing of microelectronic elements (first of all - integrated circuits) of devices for space applications for hardness to local radiation effects from heavy charged particles are presented. The possibility of a focused pulsed laser radiation application to the study of local radiation effects, caused by single heavy charged particles, is explained. The fundamentals of an approach to the construction of test sets, based on the picosecond and femtosecond lasers and systems for focusing their radiation, are considered. The main technical requirements for the basic modules of sets for laser testing (laser wavelength and pulse duration and repetition rate, spatial beam parameters and minimal spot size, speed of object movement and so on) are substantiated. All worked out sets have a full-featured software for the operational management of all modules of the laser test facility, including the positioning of the object, to provide feedback from the measurement results of the reaction of the object on the laser excitation. The parameters of developed laser hardware and software systems and their foreign counterparts are compared. Further improvement directions for laser testing tools are briefly outlined. The discussion is also presented of described hardware technical and operational characteristics, allowing to use it for a variety of scientific research studies, requiring selective (with submicron spatial resolution) object excitation by ultrashort laser pulses and recording responses to this effect with the exact timing of the moment of excitation, as well as to perform a variety of high precision technological operations.
12. Single Oral Dose Toxicity Test of Blue Honeysuckle Concentrate in Mice
PubMed Central
Park, Sang-In; Choi, Seung-Hoon; Song, Chang-Hyun; Park, Soo-Jin; Shin, Yong-Kook; Han, Chang-Hyun; Lee, Young Joon; Ku, Sae-Kwang
2015-01-01
The objective of this study was to obtain single oral dose toxicity information for concentrated and lyophilized powder of blue honeysuckle (Lonicera caerulea L., Caprifoliaceae; BHcL) in female and male ICR mice to aid in the process of developing natural origin medicinal ingredients or foods following proximate analysis and phytochemical profile measurement. The proximate analysis revealed that BHcL had an energy value of 3.80 kcal/g and contained 0.93 g/g of carbohydrate, 0.41 g/g of sugar, 0.02 g/g of protein, and 0.20 mg/g of sodium. BHcL did not contain lipids, including saturated lipids, trans fats, or cholesterols. Further, BHcL contained 4.54% of betaine, 210.63 mg/g of total phenols, 159.30 mg/g of total flavonoids, and 133.57 mg/g of total anthocyanins. Following administration of a single oral BHcL treatment, there were no treatment-related mortalities, changes in body weight (bw) or organ weight, clinical signs, necropsy or histopathological findings up to 2,000 mg/kg bw, the limited dosage for rodents of both sexes. We concluded that BHcL is a practically non-toxic material in toxicity potency. PMID:25874034
13. Transient Storage Parameterization of Wetland-dominated Stream Reaches
NASA Astrophysics Data System (ADS)
Wilderotter, S. M.; Lightbody, A.; Kalnejais, L. H.; Wollheim, W. M.
2014-12-01
Current understanding of the importance of transient storage in fluvial wetlands is limited. Wetlands that have higher connectivity to the main stream channel are important because they have the potential to retain more nitrogen within the river system than wetlands that receive little direct stream discharge. In this study, we investigated how stream water accesses adjacent fluvial wetlands in New England coastal watersheds to improve parameterization in network-scale models. Break through curves of Rhodamine WT were collected for eight wetlands in the Ipswich and Parker (MA) and Lamprey River (NH) watersheds, USA. The curves were inverse modeled using STAMMT-L to optimize the connectivity and size parameters for each reach. Two approaches were tested, a single dominant storage zone and a range of storage zones represented using a power-law distribution of storage zone connectivity. Multiple linear regression analyses were conducted to relate transient storage parameters to stream discharge, area, length-to-width ratio, and reach slope. Resulting regressions will enable more accurate parameterization of surface water transient storage in network-scale models.
14. A Test for Determining a Subdiffusive Model in Ergodic Systems from Single Trajectories
E-print Network
Yasmine Meroz; Igor M. Sokolov; Joseph Klafter
2012-10-08
Experiments on particles' motion in living cells show that it is often subdiffusive. This subdiffusion may be due to trapping, percolation-like structures, or viscoelatic behavior of the medium. While the models based on trapping (leading to continuous-time random walks) can easily be distinguished from the rest by testing their non-ergodicity, the latter two cases are harder to distinguish. We propose a statistical test for distinguishing between these two based on the space-filling properties of trajectories, and prove its feasibility and specificity using synthetic data. We moreover present a flow-chart for making a decision on a type of subdiffusion for a broader class of models.
15. Photovoltaic power system tests on an 8-kilowatt single-phase line-commutated inverter
NASA Technical Reports Server (NTRS)
Stover, J. B.
1978-01-01
Efficiency and power factor were measured as functions of solar array voltage and current. The effects of input shunt capacitance and series inductance were determined. Tests were conducted from 15 to 75 percent of the 8 kW rated inverter input power. Measured efficiencies ranged from 76 percent to 88 percent at about 50 percent of rated inverter input power. Power factor ranged from 36 percent to 72 percent.
16. Development and test of single-layer common coil dipole wound with reacted Nb3Sn cable
SciTech Connect
Vladimir Kashikhin et al.
2004-04-27
The first one-meter long common coil dipole model (HFDC-01) has been fabricated and is being tested at Fermilab. This magnet has several innovative features such as: single-layer racetrack coils, a 22-mm wide 59-strand Rutherford-type cable made of 0.7-mm Nb{sub 3}Sn strands, and a stainless steel coil-support structure reinforced by horizontal bridges inserted between coil blocks. The model was instrumented with voltage taps, quench heaters, temperature sensors and strain gauges in order to monitor the quench origin and propagation, and to study mechanical and quench protection issues. This paper summarizes the model design parameters, the fabrication procedures and the test results.
17. Design of a single flat null-screen for testing a parabolic trough solar collector
NASA Astrophysics Data System (ADS)
Moreno-Oliva, Vctor Ivn; Campos-Garca, Manuel; Romn-Hernndez, Edwin; Santiago-Alvarado, Agustn
2014-11-01
We present a null-screen design for testing the shape quality of the reflecting surface of a parabolic trough solar collector (PTSC). This technique is inexpensive, the whole surface is tested at once, and it is easy to implement. For this, we propose the design of a flat null-screen perpendicular to the optical axis of the PTSC in such a way that it allows testing of the full aperture; we compute the caustic associated with the reflected light rays on the desired surface and analyze the parameters that determine the null-screen dimensions. Additionally, we perform a numerical simulation to analyze the accuracy of the method by introducing random displacement errors into the measured data. Accuracies >0.35 mrad were found to evaluate the quality of surfaces with this method. The errors in the determination of the coordinates of the centroids of the reflected images must be measured with an accuracy >0.5 pixels, and the errors in the coordinates of the spots of the null-screen must be <0.5 mm.
18. Single-order-parameter description of glass-forming liquids: A one-frequency test
E-print Network
Niels L. Ellegaard; Tage Christensen; Peder Voetmann Christiansen; Niels Boye Olsen; Ulf R. Pedersen; Thomas B. Schrder; Jeppe C. Dyre
2007-02-28
Thermo-viscoelastic linear-response functions are calculated from the master equation describing viscous liquid inherent dynamics. From the imaginary parts of the frequency-dependent isobaric specific heat, isothermal compressibility, and isobaric thermal expansion coefficient, we define a "linear dynamic Prigogine-Defay ratio" with the property that if this quantity is unity atone frequency, then it is unity at all frequencies. This happens if and only if there is a single-order-parameter description of the thermo-viscoelastic linear responses via an order parameter (which may be non-exponential in time). Generalizations to other cases of thermodynamic control parameters than temperature and pressure are treated in an Appendix.
19. A Pilot Study on Single-dose Toxicity Testing of Hominis placenta Pharmacopuncture in Sprague-Dawley Rats
PubMed Central
Lee, Yoo-Hwan; Yoon, Hyun-Min; Jang, Kyung-Jeon; Kim, Cheol-Hong
2015-01-01
Objectives: This study was performed to analyze the toxicity and to find the lethal dose of the test substance Hominis placenta pharmacopuncture when used as a single-dose in 6 week old, male and female Sprague-Dawley (SD) rats. Methods: All experiments were conducted at Biotoxtech (Chungwon, Korea), an institution authorized to perform non clinical studies, under the regulations of Good Laboratory Practice (GLP). SD rats were chosen for the pilot study. Doses of Hominis placenta pharmacopuncture extracts, 0.125, 0.25 and 0.5 mL, were administered to the experimental group, and 0.5 mL doses of normal saline solution were administered to the control group. This study was conducted under the approval of the Institutional Animal Ethics Committee. Results: No deaths or abnormalities occurred in any of the groups. Also, no significant changes in body weights were observed among the groups, and no significant differences in hematology/biochemistry, necropsy, and histopathology results were noted. Hematologically, some changes in the male rats in two experimental groups were observed, but those changes had no clinical or toxicological meaning because they were not dose dependent. Histopathological tests on the injected parts showed cell infiltration in the male rats in one of the experimental groups; however, that result was due to spontaneous generation and had no toxicological meaning. Therefore, this study showed that Hominis placenta pharmacopuncture had no effect on the injected parts in terms of clinical signs, body weight, hematology, clinical chemistry, and necropsy. Conclusion: As a result of single-dose tests of the test substance Hominis placenta pharmacopuncture in 4 groups of rats, the lethal dose for both males and females exceeded 0.5 mL/animal. Therefore, the above findings suggest that treatment with Hominis placenta pharmacopuncture is relatively safe. Further studies on this subject are needed.
20. Computation of electromagnetic transients using dual or multiple time steps | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5947127342224121, "perplexity": 6222.366782583071}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-40/segments/1443737913039.71/warc/CC-MAIN-20151001221833-00002-ip-10-137-6-227.ec2.internal.warc.gz"} |
https://socratic.org/questions/how-do-you-find-the-sum-of-the-finite-geometric-sequence-of-sigma-16-1-2-j-1-fro | Calculus
Topics
# How do you find the sum of the finite geometric sequence of sum_(j=1)^12 16(1/2)^(j-1)?
Jul 13, 2017
Given: ${\sum}_{j = 1}^{12} 16 {\left(\frac{1}{2}\right)}^{j - 1}$
This can be written as:
$16 + {\sum}_{j = 1}^{11} 16 {\left(\frac{1}{2}\right)}^{j} \text{ [1]}$
From this reference we obtain the formula:
${S}_{n} = {\sum}_{j = 1}^{n} {a}_{j} = {a}_{1} \frac{1 - {r}^{n}}{1 - r}$
The formula fits the second term of equation [1] where ${a}_{1} = 16 , r = \frac{1}{2} \mathmr{and} n = 11$
${S}_{12} = 16 + 16 \frac{1 - {\left(\frac{1}{2}\right)}^{11}}{1 - \left(\frac{1}{2}\right)}$
${S}_{12} = 47.984375$
##### Impact of this question
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https://codereview.stackexchange.com/questions/85322/memoization-of-fibonacci-using-generic-int-int-helper | # Memoization of Fibonacci using generic Int => Int helper
I'm trying to understand memoization using Scala. I took the Fibonacci sequence as an example because of the high cost of recursively computing numbers in the sequence without memoization.
class memoize private (val f: Int => Int) {
import scala.collection.mutable
val cache = new mutable.HashMap[Int, Int]()
def memoized_f(x : Int) : Int =
cache.getOrElseUpdate(x, f(x))
}
object memoize {
def apply(f: Int => Int) : Int => Int = new memoize(f).memoized_f
}
val fib : Int=>Int = memoize((n:Int) => {
if (n <= 1) n else fib(n-1) + fib(n-2)
})
With memoization the function fib is called 10 times compared to 276 without it. I discovered that val fib is required: def fib results in the memo object being created on each call to fib!
I realize that this could eventually be generalized by parameterising memoize with a type T (or key K and value V) to replace Int. But I wanted to start somewhere simple to understand how the technique works. Given that I'm looking at memoizing only Int => Int functions, could what I've done be improved in terms of function or style?
I've also discovered a couple of related items on the web: Is there a generic way to memoize in Scala? and Memo in ScalaZ (see also this tutorial), but I'm not entirely sure how what I've done relates to them.
## 1 Answer
For generic memoization I pretty much always use scalaz Memo but when I compute sequences, I personally prefer using the standard Scala Stream.
Stream naturally memoize every computed value. Your solution could be refactored as:
lazy val fib = {
def f(a: Int, b: Int): Stream[Int] = a #:: f(b, a + b)
f(0, 1)
}
scala> fib.take(10) foreach println
0
1
1
2
3
5
8
13
21
34
scala> fib(45)
res1: Int = 1134903170 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2800464630126953, "perplexity": 5155.998317631247}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320301737.47/warc/CC-MAIN-20220120100127-20220120130127-00430.warc.gz"} |
https://projecteuclid.org/search_result?type=index&q.a.author=Takashi%20Kimura | ## Search results
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### Chern classes and compatible power operations in inertial K-theory
Edidin, Dan, Jarvis, Tyler, and Kimura, Takashi
Annals of K-Theory Volume 2, Number 1 (2017), 73-130.
Journal article
### A plethora of inertial products
Edidin, Dan, Jarvis, Tyler, and Kimura, Takashi
Annals of K-Theory Volume 1, Number 1 (2016), 85-108.
Journal article
### Logarithmic trace and orbifold products
Edidin, Dan, Jarvis, Tyler J., and Kimura, Takashi
Duke Mathematical Journal Volume 153, Number 3 (15 June 2010), 427-473.
Journal article
### On operad structures of moduli spaces and string theory
Kimura, Takashi, Stasheff, Jim, and Voronov, Alexander A.
Communications in Mathematical Physics Volume 171, Number 1 (1995), 1-25.
Journal article
### Generalized classical BRST cohomology and reduction of Poisson manifolds
Kimura, Takashi
Communications in Mathematical Physics Volume 151, Number 1 (1993), 155-182.
Journal article
### Geometric BRST quantization. I. Prequantization
Figueroa-O'Farrill, José M. and Kimura, Takashi
Communications in Mathematical Physics Volume 136, Number 2 (1991), 209-229.
Journal article
### The BRST cohomology of the NSR string: vanishing and no-ghost'' theorems
Figueroa-O'Farrill, José M. and Kimura, Takashi
Communications in Mathematical Physics Volume 124, Number 1 (1989), 105-132.
Journal article
### Homeomorphisms of zero-dimensional spaces
Kimura, Takashi
Tsukuba Journal of Mathematics Volume 12, Number 2 (December 1988), 489-495.
Journal article
### Gaps between compactness degree and compactness deficiency for Tychonoff spaces
Kimura, Takashi
Tsukuba Journal of Mathematics Volume 10, Number 2 (December 1986), 263-268.
Journal article
### On the Role of Hamiltonians in the Relativistic Dynamics referred to the New Fundamental Group of Transformations
Shibata, Takashi and Kimura, Toshiei
Journal of Science of the Hiroshima University, Series A (Mathematics, Physics, Chemistry) Volume 21, Number 1 (April 1957), 15-20.
Journal article
Select/deselect all | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.390878826379776, "perplexity": 11001.713848137157}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-10/segments/1581875146123.78/warc/CC-MAIN-20200225141345-20200225171345-00063.warc.gz"} |
http://mathematica.stackexchange.com/questions/29497/convert-a-number-to-a-string-to-use-in-plot-axes-label-but-keep-the-exponent | # Convert a number to a string to use in plot axes label, but keep the exponent
This seems to be a simple, but useful question.
I am plotting a basic function:
multiplier = 10^11;
func = 10^-11 x^2;
Plot[func*multiplier, {x, 0, 5},
AxesLabel -> {x, "Distance, \!$$\*SuperscriptBox[\(10$$, $$-11$$]\) m"}]
That gives the result I wish to see.
Imagine now that I wish not to write the multiplier manually in AxesLabel when I change it. The inverse multiplier needs to be converted to a string with an exponent (so as to produce the same final appearance). I have tried the ToString function with some parameters. For example:
multiplier = 10^11;
func = 10^-11 x^2;
Plot[func*multiplier, {x, 0, 5},
AxesLabel ->
{x, "Distance, " <> ToString[multiplier^(-1), FormatType -> StandardForm] <> " m"}]
But I get an awful label.
1. Could you think of a solution to this problem?
2. Can anyone think of why conversion to real numbers by "N" is necessary and if not how can it be avoided?
-
Perhaps "Distance, " <> ToString[N[multiplier^(-1)] can be acceptable. – Pickett Jul 30 '13 at 16:02
You needn't mess around with string manipulation. It can also be done with Row.
multiplier = 10.^11;
func = 10.^-11 x^2;
yScale = ScientificForm[1/multiplier, NumberFormat -> (10^#3 &)];
Plot[func*multiplier, {x, 0, 5},
AxesLabel -> {x, Row[{"Distance, ", yScale, " m"}, BaseStyle -> {FontFamily -> "Arial"}]}]
-
@Nasser Great. It is true that it is easier to use spaces, than Spacer[]. At the same time your yScale definition will not work for you seem to need "N" function, although theoretically it does not seem to be necessary. – Szczypawka Jul 31 '13 at 15:56
@Szczypawka. Sorry, but don't understand why I need N in yScale. The plot I show in my answer, which was made with my code, shows the correct axis label without using N. – m_goldberg Jul 31 '13 at 18:09
That's true, but just because N is hidden in your code. If you look at your code and at the other answer, you will notice that your equivalent of N is defining multiplier and func initially as real numbers by saying 10.^11, and what I am curious about is that theoretically one doesn't need such conversion. – Szczypawka Aug 1 '13 at 7:31
@Szczypawka. I wouldn't say N is hidden in my code. I just choose to work with machine real numbers right from the start. It is more efficient, especially when plotting. Further, ScientificForm is designed to work on numbers with head Real. If you insist on the constraint that inexact numbers must be avoided in answers to your question, then my answer is simply bad. But I say such a constraint would be silly when the goal is to make a plot. – m_goldberg Aug 1 '13 at 10:11
Thank you for the opinion. I don't insist that use of N is hidden in your code, and I understand well your desire to work with real numbers. And your answer is good. I use it in my code now. But you see, ideally I multiply my data by 10^11 and not 10.^11, you know, it is mathematically more precise, and I still think that it is very strange that I cannot directly put a natural number there without converting to real ones. But I appreciate your working answer anyway, because it works. :) – Szczypawka Aug 5 '13 at 9:59
Possibly something like the following:
multiplier = 10^11;
func = 10^-11 x^2;
ylabel = ScientificForm[N@multiplier^(-1), NumberFormat -> (10^#3 &)];
Plot[func*multiplier, {x, 0, 5},
AxesLabel -> {x,"Distance, " <> ToString[ylabel, FormatType ->
StandardForm] <> " m"}]
This uses ScientificForm and the option NumberFormat to control the appearance.
-
A good solution, thank you. It seems nevertheless, that "ScientificForm" is not the only possible option in the third string: "NumberForm" works also well. The only doubtful point is that one needs convertion to approximate numbers by "N" which theoretically does not seem to be necessary. But the code would not work without it. – Szczypawka Jul 31 '13 at 15:45
@Nasser That's true, great: the ToString is not needed. Still the question of using "N" stays. – Szczypawka Jul 31 '13 at 15:51 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5307791233062744, "perplexity": 1743.6225812368646}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-22/segments/1432207929832.32/warc/CC-MAIN-20150521113209-00178-ip-10-180-206-219.ec2.internal.warc.gz"} |
https://cstheory.stackexchange.com/questions/12504/implications-of-proof-of-abc-conjecture-for-cs-theory/12556 | # Implications of proof of abc conjecture for cs theory
What implications would a proof of the abc conjecture have for tcs?
http://quomodocumque.wordpress.com/2012/09/03/mochizuki-on-abc/
Bhatnagar, Gopalan, and Lipton show that, assuming the abc conjecture, there are polynomials of degree $O((kn)^{1/2+\varepsilon})$ representing the Threshold-of-$k$ function over ${\mathbb Z}_6$. For fixed constant $k$, and $m$ which has $t$ prime factors, the abc conjecture implies a polynomial for Threshold-of-$k$ over $\mathbb Z_m$ with degree $O(n^{1/t+\varepsilon})$.
This presumably has relevance to the ${\sf TC^0}$ versus $\sf ACC^0[6]$ problem. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9791696071624756, "perplexity": 302.3281006304998}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-50/segments/1606141181482.18/warc/CC-MAIN-20201125071137-20201125101137-00661.warc.gz"} |
https://e-publishing.cern.ch/index.php/CYRM/issue/archive | ## Archives
### 1955
#### Archive of CERN Yellow Reports: Monographs since 1955
You can find all monographs published since 1955 at this link.
1 - 5 of 5 Items | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9227728247642517, "perplexity": 19164.107699212662}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-51/segments/1512948513784.2/warc/CC-MAIN-20171211164220-20171211184220-00030.warc.gz"} |
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## anonymous 4 years ago PQRS is a kite. PQ = 7, QR = 11, QS = 10. M is the mid-pint of PR. Find QM^2. Delete Cancel Submit
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1. anonymous
• 4 years ago
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Can you draw a figure?
2. anonymous
• 4 years ago
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3. anonymous
• 4 years ago
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|dw:1334216371667:dw|
4. anonymous
• 4 years ago
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|dw:1334216398007:dw| M is mid pt of PR or QS??
5. anonymous
• 4 years ago
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if QS = 10 then QM = 5 5^2 is 25 right?
6. anonymous
• 4 years ago
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@lgbasallote , u r wrong.
7. anonymous
• 4 years ago
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M is mid-point of PR.
8. anonymous
• 4 years ago
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I have done the answer, shall I post it? Will u correct it?
9. anonymous
• 4 years ago
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ahhh found it now >:))
10. anonymous
• 4 years ago
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$\frac{\sqrt{24}+\sqrt{96}}{2}$
11. anonymous
• 4 years ago
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Wrong again.
12. anonymous
• 4 years ago
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that is equal to PM
13. anonymous
• 4 years ago
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Okay let me think good one. lol. Done.|dw:1334216749935:dw| wait let me type
14. anonymous
• 4 years ago
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Cos rule i guess...what is QRM=
15. anonymous
• 4 years ago
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sorry QPM?
16. anonymous
• 4 years ago
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QPM is not given.
17. anonymous
• 4 years ago
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let midpoint of QS = A sqrt (11^2 - 5^2) = AR AR = sqrt (121-25) AR = sqrt (96) AR = 4 sqrt (6) PM + AR = PR + MA PM = PR/2 PR/2 + 4 sqrt 6 = PR + MA lol =)))
18. anonymous
• 4 years ago
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so v can find it using sin x = 5/7
19. anonymous
• 4 years ago
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Shall I say how I did? Please. then u will check and rectify me.
20. anonymous
• 4 years ago
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ok?
21. anonymous
• 4 years ago
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yeah aadarsh post i am not in the patient mood to type such long replies right now.
22. anonymous
• 4 years ago
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Just a minute.
23. anonymous
• 4 years ago
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answer is 31 = QM^2= 32
24. anonymous
• 4 years ago
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31*
25. anonymous
• 4 years ago
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How u did @thushananth01 ? Can u say the reason please? U r absolutely right.
26. anonymous
• 4 years ago
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ok first find the full length of PR u can do this first by using pythagoras theorom then u have to add both and divide by 2 to get the midpoint as i gve previous with the radical..that was the length from P to M now we know PM and PQ plus the angle QPM v can find using the sin rule then i got the angle as 45.6 then finally the cose rule$p^{2}= q^{2} + m^{2} - 2qm (cos P)$ $7^{2}+7.35^{2} - 2 \times 7 \times 7.35 \cos 45.6 = p^{2}\rightarrow QM^2$
27. anonymous
• 4 years ago
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$\frac{\sqrt{24} +\sqrt{96}}{2}\rightarrow PM$
28. anonymous
• 4 years ago
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Thanks yaar.
29. anonymous
• 4 years ago
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np :)
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Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9999808073043823, "perplexity": 17374.902468207052}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-40/segments/1474738660208.2/warc/CC-MAIN-20160924173740-00210-ip-10-143-35-109.ec2.internal.warc.gz"} |
https://link.springer.com/article/10.1186/s40580-016-0078-6 | Nano Convergence
, 3:18
# Nanostructured plasmonic substrates for use as SERS sensors
Open Access
Review
## Abstract
Plasmonic nanostructures strongly localize electric fields on their surfaces via the collective oscillations of conducting electrons under stimulation by incident light at a certain wavelength. Molecules adsorbed onto the surfaces of plasmonic structures experience a strongly enhanced electric field due to the localized surface plasmon resonance (LSPR), which amplifies the Raman scattering signal obtained from these adsorbed molecules. This phenomenon is referred to as surface-enhanced Raman scattering (SERS). Because Raman spectra serve as molecular fingerprints, SERS has been intensively studied for its ability to facilely detect molecules and provide a chemical analysis of a solution. Further enhancements in the Raman intensity and therefore higher sensitivity in SERS-based molecular analysis have been achieved by designing plasmonic nanostructures with a controlled size, shape, composition, and arrangement. This review paper focuses on the current state of the art in the fabrication of SERS-active substrates and their use as chemical and biosensors. Starting with a brief description of the basic principles underlying LSPR and SERS, we discuss three distinct nanofabrication methods, including the bottom-up assembly of nanoparticles, top-down nanolithography, and lithography-free random nanoarray formation. Finally, typical applications of SERS-based sensors are discussed, along with their perspectives and challenges.
### Keywords
LSPR (localized surface plasmon resonance) SERS (surface-enhanced Raman scattering) Nanobiosensor Nanogap Nanolithography Self-assembly
## 1 Introduction
### 1.1 Surface-enhanced Raman scattering (SERS)
Raman scattering is the inelastic scattering of a photon as a result of the interaction between light and a molecule [1]. Most of the scattered photons have the same energy as the incident photons (i.e., Rayleigh scatting), but a small fraction of the scattered photons lose or gain certain amounts of energy due to energy exchange between the scattering partners. Those changes in energy (or frequency shift) are related to the characteristic energies of the vibrational or rotational modes of a molecule. Due to the high selectivity of Raman scattering, the Raman signal can be used as a molecular fingerprint for unknown molecules [2, 3]. Raman scattering spectra are typically measured using monochromatic light source (usually a laser) to excite the molecular energy levels, and scattered light is detected after interacting with the molecules of interest. Scattered photons that lose energy are called Stokes scattering, and anti-Stokes scattering corresponds to photons that gain energy relative to the energy of the incident photon. The magnitude of the energy shift is called the Raman shift and can be expressed by
$$\Delta \omega \left( {{\text{cm}}^{ - 1} } \right) = \left( {\frac{1}{{\lambda_{0} \left( {\text{nm}} \right)}} - \frac{1}{{\lambda_{1} \left( {\text{nm}} \right)}}} \right) \times \frac{{\left( {10^{7} {\text{nm}}} \right)}}{{\left( {\text{cm}} \right)}},$$
(1)
where λ0 and λ1 are the wavelengths of the incident and Raman scattered beams, respectively. Because typical Raman scattering cross-sections are much smaller than those of fluorescent processes, however, Raman spectroscopy is limited in its ability to detect molecules at low concentrations.
The weak intensity of a Raman signal may be enhanced using the localized surface plasmon resonance (LSPR) generated in the near-field of metallic nanostructures [4, 5, 6, 7]. Molecules adjacent to the metallic nanostructures exhibit significantly enhanced Raman signals [8, 9, 10, 11]. A schematic diagram of the SERS process is presented in Fig. 1. The SERS intensity of a molecule may be described as: [12]
$${\text{P }} \propto N\cdot \sigma_{SERS} \cdot \frac{{\left| {E_{loc} } \right|^4}}{{\left| {E_{0} } \right|^4}} \cdot \left| {E_{0} } \right|^{2} ,$$
(2)
where N is the number of Stokes-active scatterers (or number of molecules within the laser focal volume), σSERS is the scattering cross-section (or chemical enhancement factor), and Eloc and E0 are the amplitudes of the enhanced and incident electric field, respectively. |E0|2 is the incident laser power. Equation (2) indicates that the SERS signal is proportional to the fourth power of the field enhancement factor ($$\frac{{\left| {E_{loc} } \right|}}{{\left| {E_{0} } \right|}}$$); therefore, a field enhancement, thanks to the resonant excitation by surface plasmons in the metallic nanostructures, is highly desirable for effectively collecting SERS spectra. The sub-wavelength region of a highly localized electromagnetic field is called the “hot-spot” [13, 14, 15, 16, 17].
### 1.2 Localized surface plasmon resonance (LSPR)
The LSPR is a non-propagating surface plasmon at the surface of an isolated metallic nanostructure [18, 19, 20]. The interaction between an electromagnetic (EM) wave and a curved metallic surface applies a restoring force to oscillating electrons and amplifies the EM field along the surface of the metallic nanostructures due to the resonance [21], as shown in Fig. 2a. The EM field enhancement on the surface of a simple spherical metallic nanostructure may be explained using Mie theory. The polarizability α is defined according to
$$\alpha = 4\pi R^{3} \frac{{\varepsilon - \varepsilon_{m} }}{{\varepsilon + 2\varepsilon_{m} }},$$
(3)
where R is the radius of the metal nanoparticle, ɛ is the permittivity of the metal, and ɛm is the permittivity of the surrounding medium. As the value of ɛ approaches −2ɛm (the resonance frequency), the value of the polarizability reaches its maximum. As the polarization increases, the electric field in the vicinity (near-field) of the metallic nanostructure is enhanced. The localization of the electric field near the surface of the metal nanoparticle may be modeled using finite-difference time-domain (FDTD) calculations, as shown in Fig. 2b [22]. The electric field enhancement effect may be increased using arrays of metallic nanoparticles separated by metallic nanogaps. The relationship between the electric field enhancement and the metallic nanogap size may be calculated using a semicylinder array model, as shown in Fig. 2c, d [23]. If the distance between two metallic semicylinders (d) corresponds to twice the radius of a semicylinder (d = 2R), the electric field enhancement reaches its maximum. A 106 enhancement value is obtained from conditions in which d = 2R, corresponding to 103 times the value obtained for d = 4R. The electric field divergence near the metal nanogap for d = 2R at a resonance frequency of 2.7 eV is illustrated in Fig. 2e. The electric field was highly enhanced in the metallic nanogap region [24, 25, 26].
## 2 Metal nanoparticle assembly and bottom-up lithography
### 2.1 Shape control over metal nanoparticles
Controlling the shapes of metal nanoparticles offers a simple strategy for boosting the electric field enhancement factor near a metallic nanostructure [27, 28, 29]. As the shape of a spherical metal nanoparticle changes to triangular or star shapes, as shown in Fig. 3a–c, the electric field becomes intensified at the sharp edges of the metal nanoparticle [30]. This effect provides a high-intensity SERS signal, as shown in Fig. 3d. The SERS intensity obtained from star-shaped nanoparticles is much higher than that obtained from triangle-shape particles or metal nanospheres. The electric field enhancement effects at a metallic tip are attributed to the lightning rod effect [31]. The ratio of the surface area to the volume of the corresponding structures is a good indicator of the electron density, which is proportional to the electrostatic field. Therefore, as the edge of a metallic nanoparticle gets sharper, the electric field enhancement effect increases. Instead of creating sharp metal nanoparticles, nanogaps within metal nanostructures may be formed as a good strategy for generating a highly enhanced electric field [32]. During the formation of metal nanoparticles, a hollow gap 1 nm in size between metal nanoparticles may be produced by adopting DNA-assisted metal deposition techniques, as shown in the high-resolution transmission electron microscopy (HRTEM) image presented in Fig. 3e. The SERS intensity increases by two orders of magnitude compared to metal nanoparticles without hollow gaps, as shown in Fig. 3f, due to plasmonic coupling between the metal core and the metal shell (Fig. 3g).
### 2.2 Direct self-assembly of metal nanoparticles
The self-assembly of metal nanoparticles presents one of the simplest methods of producing highly dense intermetallic nanogaps [33, 34]. Solvent evaporation applies an inter-particle capillary force that promotes metallic nanoparticle packing. Colloidal emulsions formed by an ultrasonic homogenizer produce assembled metal nanoparticle clusters with a variety of coordination numbers as the solvent evaporates [35]. A density gradient centrifugation process may be used to sort the metal nanoparticle clusters, as illustrated in Fig. 4a. The electric field enhancement effect near the metal nanoparticle cluster has been shown to increase as the coordination number increases (Fig. 4b). These results demonstrated that the self-assembly of metal nanoparticles can provide highly efficient hot-spots through plasmonic coupling among adjacent metal nanoparticles.
The convective assembly of huge numbers of metal nanoparticles has been used to produce highly dense and sensitive metallic hot spots, as shown in Fig. 4c [36]. The initiated nucleation of gold nanorod (GNR) arrays can lead to the growth of ultra-high density arrays during solvent evaporation. A hexagonal close-packed (HCP) ordering of GNRs is formed by precisely controlling the solution concentration and temperature. Well-aligned metal nanoparticles provide uniform SERS signals.
The assembly of metal nanoparticles using Langmuir–Blodgett troughs has been used to generate highly close-packed metal nanoparticle monolayers. Alkanethiolate ligand-treated silver nanoparticles and certain analytes can be used to control the distance between close-packed silver nanoparticles in a monolayer to provide uniform and planar EM field distributions [37]. An SEM image of a monolayer of ligand-treated silver nanoparticles is shown in Fig. 4d. This highly uniform array of silver nanoparticles illustrates the linear relationship between the SERS intensity and the concentration of analyte. The detection of 50 crystal violet molecules per μm2 is possible using this type of array (Fig. 4e).
### 2.3 Colloidal lithography
Colloidal lithography is a versatile method for fabricating high-density plasmonic nanogap arrays [38]. The deposition of a silver film on the surface of a colloidal monolayer can produce rough metallic nanostructures on the colloidal particle array (Fig. 5a) [39]. An Ag film over a nanosphere (AgFON) platform has been generated by rotating the substrate during the metal deposition process. FDTD simulations have revealed that the electric field enhancement is maximized at the point at which adjacent colloidal particles meet, as shown in Fig. 5b. Figure 5c shows that the spin-cast deposition of colloidal metal nanoparticles onto silicon substrates generates uniform hexagonally close-packed arrays.
Other approaches to LSPR generation include deposition of a dielectric interlayer onto the top surface of an AgFON using the atomic layer deposition method [40]. As shown in the experimental procedure used to prepare metallic nanogaps on AgFON substrates (Fig. 5d), an aluminum oxide (Al2O3) layer as well as the subsequently deposited Ag film produced a metal/dielectric/metal multilayer that is useful for generating plasmonic coupling at the metallic nanogaps after partially removing the aluminum oxide layer using a buffered oxide etchant. Figure 5e shows scanning electron microscopy (SEM) images of a nanoring cavity on an AgFON substrate. FDTD simulation data presented in Fig. 5f reveal that the intensity of the electromagnetic field is highly localized at the 10 nm gaps of the silver nanostructures. This approach provided a maximum enhancement factor of 108, higher than that obtained from conventional AgFON SERS templates, typically 107.
### 2.4 Block copolymer lithography
The self-assembly of block copolymers provides ordered polymeric nanostructures with a variety of geometries [41, 42, 43]. The selective deposition of metals onto one part of a polymer produces well-ordered metal nanostructures. The procedure used to fabricate gold nanosphere arrays using block copolymer self-assembly is illustrated in Fig. 6a [44]. A thin film of the self-assembled block copolymer PS-b-P4VP (polystyrene-b-poly(4-vinylpyridine)) produces hexagonally ordered P4VP cylinders with a PS surrounding medium due to the segregation of the hydrophilic and hydrophobic parts. Gold nanoparticles slightly larger than the P4VP domains were attached to the P4VP sites through electrostatic interactions. The gap size between adjacent gold nanoparticles could be tuned by controlling the metal overgrowth. Figure 6b shows SEM images of hexagonally arranged gold nanoparticle arrays with different overgrowth times. As the overgrowth time increased from 0 min to 3, 7, and 15 min, the average size of the metal nanoparticles increased from 16.6 nm to 24.8, 32.7, and 36.5 nm. Correspondingly, the gap between the particles decreased from 23 nm to 14.6, 9.5, and 4.1 nm, respectively. Figure 6c shows SERS spectra of 4-aminobenzenethiol in the presence of substrates prepared using different overgrowth times. The SERS intensity measured from the 7 min overgrowth substrate was the highest because the wavelength of the LSPR peak matched the wavelength of the incident light and the Stokes Raman shift of 4-aminobenzenethiol. As an alternative to attaching the gold nanoparticles onto the block copolymer surfaces, the metal precursor has also been reduced onto block copolymer micelles to form compartments and assemble the metal nanoparticles within the micelle. As shown in Fig. 6d [45], silver nanoparticles could be loaded into the P4VP regions of a PS-b-P4VP block polymer micelle by adding AgNO3 and NaBH4. Silver nanoparticle clusters could be packed and remained on the substrate in a hexagonal arrangement after monolayer deposition of the micelle and the subsequent removal of the PS-b-P4VP block polymer. The distance between neighboring silver clusters was determined by the molecular weight percent of PS, whereas the diameter of the silver nanocluster was preserved. Figure 6e, f show silver nanocluster arrays with different inter-particle distances.
## 3 Top-down nanolithography
### 3.1 Electron beam lithography
Electron beam (e-beam) lithography can be used to fabricate desired high-resolution nanostructures that are not easily prepared using other fabrication methods [46, 47]. The high degree of freedom available for e-beam lithography has enabled studies of the basic principles underlying electric field enhancements by well-designed metallic nanostructures [48, 49]. Metal nanostructures with high electric field confinement effects have been prepared using concentric rings of plasmonic necklaces deposited near metal nanoparticles dimers, as shown in Fig. 7a–e [50]. The introduction of concentric rings around metal nanodisk dimers significantly concentrates the electric field at the gap within the dimer region. The intensity of the electric field increases as the number of necklaces increases, as shown in the FDTD simulations presented in Fig. 7f. The SERS signal of a p-mercaptoaniline (pMA) monolayer on the surface of a double necklace was much higher than that obtained from a single necklace or a single dimer structure (Fig. 7g). The LSPR wavelength can also be tuned via precise control over metal nanostructures. The fabrication of a gold nanodisk on the top surface of a silica spacer-coated gold film creates a double-resonance plasmonic substrate, as shown in Fig. 7h, i [51]. The double resonance between the localized surface plasmons (LSPs) and the surface plasmon polaritons (SPPs) occurs due to variations in the distance between the gold nanodisks. The distance between gold disks is the main factor that determines the position of the plasmon resonance. As shown in Fig. 7j, a distance between two adjacent gold nanodisks of 780 nm produces dominant LSPs and SPPs, and the extinction spectra exhibit two main peaks (the peak position at the higher wavelength is the LSP). The tunability of the LSPR position is beneficial for SERS applications because the intensity of the SERS signal is higher if the LSPR wavelength is located between the wavelength of excitation and the Raman signal. For example, nanodisk arrays separated by a distance of 350 or 500 nm distance displayed a higher SERS intensity than nanodisk arrays separated by a distance of 750 nm in the presence of benzenethiol excited at 421 cm−1, because the LSPR position of the nanodisk arrays with 350 and 500 nm separation distances is much closer to the wavelength of excitation (783 nm) and Raman signal than is the case for the arrays with a 750 nm separation distance (Fig. 7k).
### 3.2 Nanoimprint lithography
Nanoimprint lithography is useful for the generation of highly reproducible nanostructures [52, 53, 54, 55]. The limitations of nanoimprint lithography in SERS applications have been the high fabrication costs associated with the master mold and the limited resolution at which few nm gap structures may be generated. To overcome these problems, several approaches to creating highly efficient metallic nanogaps with effective electric field confinement have been developed. The coalescence of nanocylinder arrays using capillary force is useful for fabricating nanogaps that enhance the electric field confinement [56]. After depositing gold onto the heads of a polymeric nanocylinder array, introduction of an analyte solution dropped onto the arrays induced the nanocylinder arrays to close under capillary forces. Figure 8a, b show the fabrication steps and SEM images of the resulting assembled nanocylinder arrays. The SERS signals obtained from trans-1,2-bis (4-pyridyl)-ethylene (BPE) in different geometries are compared in Fig. 8c, d. Symmetric structures, such as diagonal, tetragonal, and hexagonal arrays, exhibited relatively low intensities compared to the asymmetric trigonal and pentagonal structures, as supported by the FDTD calculations (Fig. 8e).
Cavity coupling among plasmonic nanostructures can be obtained using molding techniques and subsequent metal deposition, as shown in the schematic diagrams of Fig. 8f. [57]. Figure 8g shows the square array of cavities. Plasmonic coupling effects occur in both the L1 and L2 cavities to provide a tunable plasmonic resonance wavelength by controlling the cavity size. A well-designed cavity may produce a highly localized electric field near the metal surface, resulting in a high-intensity SERS signal from benzenethiol, in contrast to the non-efficient cavity, as shown in Fig. 8h. Interestingly, the band at 1574 cm−1 was higher than the 1073 cm−1 peak band because the 1574 cm−1 band is close to the approximate maximum SERS intensity range of $$\left( {\lambda_{\text{LSPR}} \approx {{\left( {\lambda_{\text{Ex}} + \lambda_{\text{Raman}} } \right)} \mathord{\left/ {\vphantom {{\left( {\lambda_{\text{Ex}} + \lambda_{\text{Raman}} } \right)} 2}} \right. \kern-0pt} 2}} \right)$$.
### 3.3 Laser interference lithography
Laser interference lithography uses interference among several monochromatic light sources with different wavevectors, polarizations, and phases to fabricate periodic nanostructures [58, 59, 60]. The laser interference patterns produce highly uniform and reproducible SERS substrates [61]. Complex alignment of an optical set-up may be avoided by using prism holographic lithography and phase-shift lithography with a diffraction grating. Prism holographic lithography uses a well-designed prism to split incident light into several beams with a certain wavevector profile [62]. The use of a top-cut triangular pyramid prism (Fig. 9a, b) produces a four-beam interference pattern from a single laser exposure, which generates face-centered cubic (FCC) structures, as shown in Fig. 9c. The interference pattern is transferred to the thin film of a photoresist to generate hexagonal arrays of three elliptical holes [63]. The patterned photoresist film is used as an Ar-milling mask to remove exposed areas of gold. The resulting patterned gold structures are used as a catalyst to etch the underlying Si wafer in a solution containing deionized water, hydrogen peroxide (H2O2), and hydrofluoric acid (HF). Finally, well-ordered silicon nanowires (SiNWs) have been fabricated with various lengths, depending on the etching rate. Highly uniform silicon nanowires can act as hot spots after Au deposition. The fabrication procedures and final nanostructures are illustrated in Fig. 9d, e–h. A small gap between top and bottom gold films provides an efficient electric field enhancement effect, resulting in a high-intensity benzenethiol SERS signal, as shown in Fig. 9i.
Laser interference patterns generated by a diffraction grating are advantageous for the fabrication of reproducible 2D and 3D periodic nanostructures over large areas (comparable to the laser beam size) using a single laser exposure [64]. Unlike prism holographic lithography, phase-shift lithography uses the interference among several diffracted light beams split by a diffraction grating. The interference patterns of the diffracted beams generated in the Fresnel regions are transferred to the photoresist film to generate ordered nanopillar arrays with a rectangular arrangement. During the laser interference patterning process, beams reflected from the interface between the photoresist and the underlying substrate produce a vertical standing wave by combining with the incident light to generate a vertical undulating pattern on the sides of the nanopillar arrays [65]. A schematic diagram of the laser interference lithography method using a diffraction grating is shown in Fig. 9j. FDTD simulation data reveal that substrate with higher refractive index causes higher intensity of the reflected beam, thereby resulting in clearer undulating patterns on the side walls of nanopillars (Fig. 9k). As shown in Fig. 9l, m, nanopillar arrays produced on a silicon wafer display much clearer undulating patterns, whereas nanopillar arrays formed on a glass wafer have indistinct undulating patterns. The smooth-surface nanopillar arrays were prepared and the SERS spectra of benzenethiol were measured on three different substrates (Fig. 9o). The intensity of the SERS signal obtained from the undulating nanopillar array was much higher than that obtained from the indistinctly undulating nanopillar array, and the smooth surfaces of the nanopillars provided no SERS signal at all. The electric field was significantly enhanced at the metallic nanogaps on the side walls of the undulating nanopillars (Fig. 9p). The undulating nanopillar array provides high uniformity of SERS intensity over wide area (Fig. 9q).
## 4 Nanolithography-free random array generation
### 4.1 Maskless dry-etched silicon template
SERS substrates have been fabricated without nanolithography techniques by applying the maskless reactive ion etching (RIE) of silicon substrates, as shown in Fig. 10a [66]. Careful control over the RIE process conditions can yield free-standing Si nanopillars with the desired pillar height and width. Silver is deposited onto the random nanopillar arrays by evaporation or sputtering methods. It should be noted that nanopillar leaning is crucial for obtaining large SERS signals, as in the case of the polymeric pillar substrates fabricated by nanoimprint technology. Evaporation deposition was found to be favorable for preparing silicon lumps at the tops of Si pillars during deposition. By contrast, conformal silver coatings formed using sputtering methods resulted in rigid pillars and yielded poor SERS performances. The leaning effect produced metallic nanogaps (hot-spots) during solvent evaporation, and the SERS characteristics of these substrates improved, as shown in Fig. 10b. The droplet contact region produces high-intensity of SERS signals compared to other regions due to the strong plasmonic coupling among the leaning nanopillar arrays. The advantages of maskless patterning without a lithographic step enables the preparation of cost-effective consumable SERS substrates. A SERS enhancement factor on the order of 2.4 × 106 was claimed, and the signal uniformity over large areas, that is, the 4 in. wafer scale, was demonstrated.
### 4.2 Hydrothermally roughened metal templates
Boiling aluminum thin films coated onto glass transforms a flat metallic films to a sharp-edged leaf-like superstructure of boehmite (Fig. 10c) [67]. Random boehmite arrays have been used as templates for gold deposition to produce gold nanocoral (GNC) surfaces. By optimizing the Au deposition, effective plasmonic nanostructures could be obtained with a gap spacing of <10 nm. During the gold deposition step, a gold film is not generated in the valleys of the boehmite structures, and the growth of gold is initiated on the ledges, resulting in the formation of hot-spots. The analytical enhancement factors of these substrates are on the order of (1–3) × 104, and uniform SERS signals are obtained over large areas. These substrates perform sufficiently well to support their use in the construction of two-dimensional Raman maps for tissue imaging.
### 4.3 Hybrid methods of random hot-spot generation
A hybrid fabrication method involving random stacking of Ag nanowires and vacuum-deposition of Ag nanoparticles, has been reported [68]. The simple filtration of Ag NWs using a glass fiber membrane renders a random stacking of high-aspect-ratio nanowires (Fig. 11a, b). Despite the random configuration, the stacked Ag NWs plates show effective plasmonic characteristics due to the huge number of hot-spots present at the crossing points of the NWs. Plasmonic coupling may be further promoted by decorating the stacked NWs with Ag nanoparticles. The presence of a 10 nm thick alumina interlayer serves as an effective dielectric gap between the NPs and NWs, and the nonwetting properties of the Ag film on the surface facilitates the island-type growth of Ag during vacuum deposition (Fig. 11c). The 3D hybrid plasmonic nanomaterials exhibited near-perfect absorption across the visible wavelength range (averaged reflectance <2 %) and ultrasensitive SERS performances.
SERS substrates consisting of silver nanoislands have been prepared on other supporting plates, such as glass nanopillar arrays or papers [69]. The glass nanopillar arrays were fabricated by reactive ion etching through an annealed Ag nanoisland mask. Thermal evaporation of Ag onto the nanopillar arrays yields a high density of Ag NPs on both the tops and sidewalls of the nanopillars, similar to the nanoislands growth described above in the context of the Ag NW stacked plates. Laser illumination of the Ag films deposited onto paper fibrils can facilitate the formation of highly dense Ag nanoparticles [70]. The quasi-3D distribution of Ag NPs on the paper provides effective SERS signals throughout the detection area.
## 5 SERS-based sensor applications
The simple, sensitive, and rapid detection of trace levels of highly toxic molecules and biomarkers are in urgent demand for environmental monitoring and public health applications [71, 72]. The fabrication of reliable, reproducible, and low-cost SERS substrates are a prerequisite for these general chemical and biosensing applications [73, 74, 75, 76, 77, 78, 79, 80]. The development of portable Raman spectrometers can enable a variety of field tools, such as food or environmental security tests, bio-imaging devices, and bio-sensors, as shown in Fig. 12.
### 5.1 Rapid and on-site detection of analytes using portal Raman systems
Despite the high sensitivity of SERS substrates, the need to pre-treat samples limits the practical utility of SERS substrates as molecular sensors. In real environmental systems, analytes are mixed with other molecules, and the separation of target molecules should be conducted prior to collecting Raman measurements. Thin layer chromatography (TLC)-based techniques show promise as a simple process for separating molecules [81]. The TLC approach separates molecules according to the rate at which they travel through a thin layer due to differences in the attractive forces between the molecules and the film, as well as the differential solubility of the molecules in the solvent. Dropping silver particles onto the molecules separated on a TLC plate permits the on-site detection of analytes using a portable Raman spectrometer, as shown in Fig. 13a.
The size-selective separation of analytes is useful for detecting small molecules dispersed in a mixture, such as human blood or commercial beverages. Hydrogels can separate target molecules from a mixture using their small mesh size [82]. Molecules with a size smaller than the mesh size of the hydrogel can diffuse into a gold nanoparticle-encapsulated hydrogel, whereas larger materials are excluded. Figure 13b, c show the effects of a hydrogel on the size-selective diffusion of molecules. Gold nanoparticles that simultaneously come in contact with both rhodamine 6G (R6G) and bovine serum albumin (BSA) do not provide a detectable R6G Raman signal due to interference by BSA; however, encapsulating gold nanoparticles in a hydrogel allows only the R6G molecules to diffuse into the gel, and R6G detection is possible.
### 5.2 Food and environmental security control
Safety tests conducted using SERS substrate offer a promising method due to the high sensitivity and selectivity of the SERS substrate. Small quantities of toxic molecules on the surfaces of food may be detected using well-designed efficient SERS substrates [83]. Plasmonic nanopillar leaning during solvent evaporation provides a high-intensity SERS signal due to plasmonic coupling among adjacent plasmonic nanopillar arrays. Different concentrations of thiabendazole (TBZ) molecules were introduced onto the surfaces of apples, which were then rinsed with DI water. The rinse water was then introduced to the prepared SERS substrates. The SERS measurements could detect a 7 ppb concentration of TBZ molecules, lower than the Environmental Protection Agency (EPA)’s detection limit.
The detection of bacteria during the early stage of an infection can prevent severe human disease. High-sensitivity SERS substrates can detect small numbers of bacteria and prevent bacterial activation. Figure 14A shows bacteria detectable SERS substrate composed by silver nanoparticles@Si nanoparticles arrays treated with 4-mercaptophenylboronic acid (4-MPBA) on the surface. [84] Bacteria captured on the surface of a 4-MPBA treated SERS substrate will provide an enhanced Raman signal from bacteria wall due to the interaction between the bacteria and the 4-MPBA-treated silver nanoparticles. Figure 14B shows the Raman spectra obtained from SERS substrates treated with E. coli or S. aureus. The signal at 730 cm−1 corresponded to the Raman signal of the glycosidic bonds in the bacterial wall. The dotted box shows the Raman signal of the bacteria.
Arsenic (As) contamination in soil or groundwater causes severe health problems [85]. Among the As states, arsenite (As(III)) is much more toxic than arsenate (As(V)). The oxidation states of As should, therefore, be distinguished during environmental toxicity assays. The use of Fe3O4@Ag nanoparticles (Fig. 14C) permits the detection of As contamination [86]. Sixteen groundwater samples from different locations were quantitatively analyzed for their As contamination using the Raman spectra collected at Fe3O4@Ag nanoparticles, as shown in Fig. 14D.
### 5.3 Bio-imaging and bio-sensing
Bio-imaging using a SERS substrate can detect dispersions of specific molecules in bio-systems [87]. Figure 15a shows the SERS spectra collected from mouse ischemic brain tissues in two different regions: an ischemic core and a contralateral region [67]. The main intensity differences were observed at 518 and 736 cm−1, and the intensity mappings of the mouse brains at two different Raman bands are shown in Fig. 15b. The intensity of the 518 cm−1 band was larger in the control region, whereas the intensity of the 736 cm−1 band was larger in the ischemic region. To understand which molecules were associated with ischemia, the SERS spectra of eight adenylates were measured, as shown in Fig. 15c. The SERS spectra indicated that adenosine, inosine, and hypoxanthine display large SERS intensities at 736 cm−1. These results verified that adenosine, inosine, and hypoxanthine molecules were associated with ischemia. Figure 15d shows the Raman mapping of adenosine and inosine onto the both ischemic and control samples.
Infinitesimal amounts of biomarkers (glucose, DNA, virus, drug) can crucially impact the viability of living organisms [88, 89]. The detection of biomarkers in a biological fluid is important for a variety of healthcare assays. For example, blood glucose levels are normally maintained between 3.9 and 5.5 mM. Diabetes mellitus patients does not regulate blood glucose levels within the normal range, and must watch these levels continuously. SERS-based glucose sensors have been fabricated using an AgFON substrate onto which has been adsorbed a decanethiol (DT)/mercaptohexanol (MH) mixture capable of trapping glucose near the surface, as shown in Fig. 15e [90]. The left-hand panel of Fig. 15f shows the SERS spectra acquired at a DT/MH modified AgFON during glucose cycling (from graphs A to E). Graphs F and G illustrate the difference between the spectra obtained at 100 or 0 mM glucose. These spectra may be compared to the spectrum obtained from a standard glucose solution (graph E), as shown in the right-hand panel of Fig. 15f. The high sensitivity of the SERS substrates to glucose molecules is apparent from these spectra. In another example, DNA analysis is important for diagnosing genetic diseases or cancers. Double-stranded DNA (dsDNA) may be selectively sandwiched between two spermine molecule-coated silver nanoparticles (AgNP@Sp) via electrostatic interactions to simultaneously provide an enhanced Raman signal from the DNA via plasmon coupling between the two neighboring silver nanoparticles, as shown in Fig. 15g [91]. The Raman signal corresponding to the dsDNA is amplified at the interparticle junctions, and the Raman spectrum of the dsDNA agrees well with that of the single-stranded sequences, as shown in Fig. 15h. This experiment demonstrated that SERS can distinguish between nucleotide sequences in DNA.
## 6 Summary and outlook
Over the past four decades, since the discovery of SERS, a series of theoretical and technological innovations have stimulated broad interest in plasmonic nanomaterials. Advances in nanoparticle synthesis and assembly have benefited this research are. A variety of nanolithographic techniques have been developed for generating efficient SERS structures, including bottom-up lithography using colloidal templates, top-down methods using e-beam lithography, nanoimprint lithography, and laser interference lithography. From a practical point of view, simple and low-cost methods of fabricating SERS substrates are in great demand. The lithography-free hot-spot generation methods show particular promise in commercial applications, given their improvements in reproducibility and reliability.
The high sensitivity and molecular fingerprinting capabilities of the SERS technique have identified this technique as a powerful analytical tool in a wide range of chemical and biosensing applications. Practical applications of SERS technologies are under rapid development. Recent progress toward the fabrication of SERS substrates, as reviewed in this article, has been quite promising. On-site ultrasensitive SERS sensor platforms may potentially be prepared by combining SERS substrates with portable Raman spectrometers. Standard sample pretreatment protocols and the capacity for quantitatively analyzing specific target applications are needed to advance future SERS technologies.
## Notes
### Authors’ contributions
TYJ and DJK participated in the literature survey and drafted the manuscript. S-GP, S-HK and D-HK coordinated and helped to draft the manuscript. All authors read and approved the final manuscript.
### Acknowledgements
This study was supported financially by the Fundamental Research Program (PNK4660) of the Korean Institute of Materials Science (KIMS). S.-G. Park is grateful for support from the Basic Science Research Program of the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (NRF-2015R1C1A01053884).
### Competing interests
The authors declare that they have no competing interests.
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## Copyright information
© The Author(s) 2016
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
## Authors and Affiliations
• Tae Yoon Jeon
• 1
• Dong Jae Kim
• 1
• Sung-Gyu Park
• 2
• Shin-Hyun Kim
• 1
• Dong-Ho Kim
• 2
1. 1.Department of Chemical and Biomolecular Engineering (BK21+ Program)KAISTDaejeonRepublic of Korea
2. 2.Advanced Functional Thin Films DepartmentKorea Institute of Materials Science (KIMS)ChangwonRepublic of Korea | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 2, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7176980972290039, "perplexity": 10265.343028513013}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-34/segments/1502886106754.4/warc/CC-MAIN-20170820131332-20170820151332-00680.warc.gz"} |
http://khye.psychanalyste-19e.fr/80-pcc-lower.html | ## 80 Pcc Lower
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Because an 80% lower (or 80% frame for a handgun) is not fully fabricated and is not functional, it's not considered a firearm. … The earnings for the first quarter of 2020 were likewise below our expectations and down on the previous year. Building Tools. strain PCC 6803 cells that preserves the in vivo plastoquinol ([PQH2][2]) to -[PQ][1] ratio. 45 ACP and 10mm Glock large frame caliber magazines. Single shot lower intended for use with our SHTF 50 uppers. Participants Patients visiting the outpatient. 5" high-Res (800×480) WVGA Color LCD. Specifically, we propose that what German copula constructions have in common with PCC environments is that there are multiple accessible DPs in the domain of a single agreement probe, the lower of which is more featurally specified than the higher (see, e. 80% Lower Receivers. FIREARM WARNING. 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Note: ** Windows 7 and Windows8 : USB interface is supported but SCSI interface is not supported. 2c) suggesting that while the former may be suitable as a model organism for initial metabolic engineering studies, the latter may be more suitable as a host for production (Fig. Sort by popularity Sort by average rating Sort by latest Sort by price: low to high Sort 9MM AR9 80% Lower Receiver with Extractor and Mag Release. WISMEC Sinuous V80 - боксмод. Add optional laser engraving for states requiring a serial number and receive a$10 discount when bought with the lower: Custom Laser Engraving. Complete your 80% pistol with 80% Arms! Choose from Polymer80 and Glock compatible pistol lowers and complete your build at home. A - application / limit working conditions. Model-based simulations indicated that at baseline INR 3. competition accessories. Gift Certificates; Wishlist; Login or Sign Up; Shipping & Returns. IEC255-7 High switching capacity - 40A for 1 Form A Low coil consumption Small size, light weight, PCB mounting. Lisa Anderson, PCC Chief Deputy of Administration and Operations Stephen W. This finding was consistent with the phenotype of a ndhF1-null strain of Synechococcus sp. 85% shall be the maintaining average for all courses/ program and no grade lower than 80%. Ryzen 5 3600 x370 stuck 0. An 80 percent lower is the easiest and most affordable way to become the proud new owner of an AR-15 rifle or pistol without having to deal with an FFL, government paperwork, or extra taxes and bureaucratic fees. That's after incomes have been adjusted for household size, since smaller. 94 a specific surface area (BET) at 18. Includes our integrated feed ramp for reliable feeding. , Béjar and Rezac 2003, 2009; Anagnostopoulou 2005; Nevins 2007). Today we are going to be finishing an AR-15 lower receiver from the G150 kit from Polymer80. AR 80% Lower Receiver - Billet - Raw - Blemished. The lower the particle. Bottom line: Walking just 30 minutes a day can help lower your blood pressure. However, during the "reign" of Oliver Cromwell, the Bishop's Courts were abolished, and all wills were proved at the PCC from 1653 through 1660. The lower the better. 55 ghz and low memory read and writespeed (0). Envío gratis con Amazon Prime. Maison Margiela x Reebok Instapump Fury Tabi PumpBlack Patent. The dedicated AR-45 80% percent lower receiver build accepts. After high-performance liquid chromatography. , doubling time of S. Polymer80 RL556V3 (AR15) 80% Lower with Jig System. The boat is better suited for ocean passages (vs coastal cruising) if the result of the calculation is 2. It was observed that PCC partly substituted for TiO2 can improve the stability, scrub resistance, brightness and coverage of produced paints. Sort by Default Order. Gutierrez, PCC Director, Property Tax Department. LCM Calculator shows the work to find the LCM with prime factorization, factor tree, cake/ladder/box method, division method, listing multiples. VR80 Accessories (15). 1%) developed thromboembolic events after 4F-PCC administration. 56 Mounting. Quartz crystal. 00 Cost of new grave (PCC) £2000. Quick View. 8 Star Rating on 17 Reviews for Pro Mag AR10 Lower Receiver Vise Block Kit PM245 Best Rated + Free Shipping over $49. The Lower Level Exhibition Hall has a 350 pounds/square foot floor weight capacity. Alcoholic beverage, beer, light, low carb. Cerakoted AR9 80% Billet Lower Receiver. True you will not be able to make 600 yard shots with it, but then again there are so few places to actually shoot that far anyways that most of us are limited to 100 yards or less which is absolutely. Self Closing (2) › Degree of Opening. 00 See details. The best parts and accessories to build your budget, mil-spec, or ultimate AR-45. 00 miles long, had present worth costs of$157,528 by comparison. Be sure to also check out our selection of 80% pistol frame kits from Polymer80 , featuring precision-machined frame kits to fit Glock 19, 23 and 32 models as well as 1911s. PCC 80% Billet AR-9 Lower with Jig As low as $0. 10000 hours. Explore air quality in your city and around the world. But consider setting to a lower number for more accurate enumeration of split candidates. Select options. * Execute the downloaded file. The final PCC was colloidal PCC with a median particle size at 1. With a spouse or common-law partner - Maximum 460 Scored NCLC 7 or higher on all four French language skills and scored CLB 4 or lower in English (or. The Dirty Bird PCC (9mm /. The description for Windows 7 and Windows 8 is not in the manual yet. VTE prophylaxis (THA, TKA) Europe – Mar 2008. IC-9 lower receiver - designed to pair up with a standard MILSPEC ar-15 upper or our berserker lite upper. Out of stock. Supplementation with L. Build your own Glock 17 compatible pistol with this PF940Cv2 kit. Oct 3, 2017 - Explore B. FFL RESTRICTION Federal law requires this product to be transferred through a licensed FFL dealer. Along with its over-sized mag release, the lower features massive magwell ramps to aid in reload; a feature not found on any other PCC lower. Note: If side and lower side is imbalanced, adjust "PCCHG" and "PCCLG" so that. q Low self discharge. The AKG Acoustics PCC-130 is a surface-mounted small cardioid microphone of professional Included with each PCC-130 is a 4, 6-m (15-ft. * Execute the downloaded file. However since JP isnt selling GMR15 lowers for home builds yet. Biuro w Gdyni Centrala spółki. To fabricate the optional 80% lower, you'll need the AR9 80% jig. *lower is not included*. Don’t shoot it anymore. Set $$\sigma$$ to 1 and $$\mu$$ to 0. These FM-9 Billet Lower Receivers are totally stripped and ready for all standard mil-spec AR-15 components, making them a solid starting point for your novel PCC build. Along with its over-sized mag release, the lower features massive magwell ramps to aid in reload; a feature not found on any other PCC lower. This AR-15 build set includes one 80% lower receiver and one. Apply a Crosshatch pattern. Specifically, we propose that what German copula constructions have in common with PCC environments is that there are multiple accessible DPs in the domain of a single agreement probe, the lower of which is more featurally specified than the higher (see, e. Please email us a copy of your Dealers FFL license to [email protected] We recommend Magpul, OEM Glock and ETS magazines only. CMMG MkG GUARD. This AR9 80 lower works with mil-spec AR-15 lower parts kits and mil-spec buffer tubes and castle nuts. Special Bundle Includes: PWS PCC 9. Note: 80% Lower Receivers, Frames, and Kits may only be returned in new, unmodified condition. 0 80 59 45 M. PRIMA LED Ex 1. This elegant over/under carries a tremendous amount of family tradition, from a. *lower is not included*. UNMATCHED RELIABILITY Power consumption is much lower than traditional hard drives. Students who are certified with 39 semester units of lower-division GE-Breadth units will only be required to complete a minimum of nine semester (13. 91% ↓ Mar-2019 Notes: Tolerance: subject value is within or outside calculated upper or lower limits of normally expected variations in performance. The magnitude of the difference in thromboembolic rates is notable and suggestive though cannot prove PCC has lower thromboembolic events. However, patients receiving PCC had a significantly lower incidence of coagulopathy requiring open chest and delayed sternal closure (23% vs 3%, p = 0. The final PCC was colloidal PCC with a median particle size at 1. These Noreen 80%. The MkG series is a great platform to base your PCC build on!. There was not a difference in the reversing effect between different doses of PCC (P=0. our proprietary manufacturing process allowS us to make carbon fiber barrelS faster and more efficiently. 0045 rejecting null hypothesis of inferiority of 4F-PCC. The Pleatco PCC80-PAK4 is a complete set of four replacement filter cartridges for the Pentair Clean & Clear Plus 320. The Lightning carbon fiber handguards keep your rifle light and cool, the Fury titanium compensators keep your muzzle flat so you can dominate the competition!. Pheochromocytoma (PCC) has been referred to as “the 10 percent” tumor due in part to the belief that 10% are hereditary and usually associated with 3 well-known cancer syndromes: von Hippel–Lindau disease, multiple endocrine neoplasia type 2, and neurofibromatosis type 1 due to mutations in VHL (), RET (), and NF1 (), respectively. 3) FM Products does not support Spikes Glock style lower receivers. , Béjar and Rezac 2003, 2009; Anagnostopoulou 2005; Nevins 2007). 62 Check back soon!. The role of serine/threonine protein kinases (STPKs) in the cold response was studied in Synechocystis. Since it still needs some finishing touches, it is not a firearm until you complete it. Start studying Nursing Abbreviations 100-150 PCC NU203. Lower Receiver - Skeletonized PCC /AR-9 LSA-9 (Black) Our premier lower receiver is the ultimate in precision! Designed for much tighter tolerances to unleash the full accuracy of the AR-9. Product Description The Polymer80, Phoenix2, AR15 80% Lower and Jig System Includes the Phoenix2 system This system is designed as a complete kit. ,100% high quality. diabeteswithtype 😱carbs allowed per day. The MkG series is a great platform to base your PCC build on!. Learn vocabulary, terms, and more with flashcards, games, and other study tools. 9mm (115gr vs 124gr vs 147 HP) Really, the major thing you need is a new upper and the right magazines. Objectives Percutaneous cervical cordotomy (PCC) is an interventional ablative procedure in the armamentarium for cancer pain treatment, but there is limited evidence to support its use. Low Sulphur Contribution Low Sulphur Surcharge Low Surplur Fuel Surcharge. Rock River Arms, Inc. The map_diag is slightly different because it takes in a function that accepts a single array (remember the diagonal. Polymer80 PF940SC 80% Textured Pistol Frame Kit for Glock G26/G27. Discover the latest fashion & trends in menswear & womenswear at ASOS. 80% Lower Receivers. Start studying Nursing Abbreviations 100-150 PCC NU203. PCC EXPANSION CONCEPT –YEARS 6 TO 10 Expansion would result in: • Lower level hall at 312,500 sf; • Upper level hall at between 300,000 and 340,000 sf. Be sure to also check out our selection of 80% pistol frame kits from Polymer80 , featuring precision-machined frame kits to fit Glock 19, 23 and 32 models as well as 1911s. As low as$0. Evaluation of mechanical behaviour of the rubberized PCC mortar in fixed W/C ratio. 99 Add to cart. All of our 9mm lowers ship complete with mag release and ejector. 4ft PCc 8800/840 Mxh 40 8800 7190 58 124 4,0 1272 700 PRIMA LED Ex 2. PPCs have become increasingly popular in the United States and it's easy to see why:. Build your dream gaming PC with iBUYPOWER. Blood pressure table showing if adults and children have high, low, or healthy average blood pressure range for their age, includes other helpful cardiac related information. 5 Groove High Quality Chrome Molly, 1x10 Twist, Shot Peen Black Oxide Finish. Use of recycled concrete results in a savings of natural aggregates. 80 percent lower receiver No FFL required and All machine work that has been done is within 80 percent complete No FFL required, these are not lower receivers but are 80% complete until the. I eventually ended up reaching out to BLS and got my PCC within a week. A majority of billet lower receivers feature an integrated trigger guard, which can help add to the stiffness of the lower itself. Designed to be the first net-zero-energy higher education building in Oregon (and the second in the United States), the Newberg Center supports PCC’s sustainable mission to reduce greenhouse gas emissions 80% by 2050. The only difference is the caliber that the pistol is chambered in. Once there, you can verify that the Ruger ® firearm you seek is available through that retailer and order it, subject to all federal, state and local laws. The AKG Acoustics PCC-130 is a surface-mounted small cardioid microphone of professional Included with each PCC-130 is a 4, 6-m (15-ft. Stripped Receivers and Complete Lowers. From some reading it sounds like qc10 is hit and miss and the NFA upper can work with some tweaking. Gutierrez, PCC Director, Property Tax Department. Obsługa kierowców: tel. Enjoy FAST SHIPPING and SAVE at 80-lower. 0% Mar-2019 Complaints Complaints against officers* 45 557 13. While most 9mm-specific components will be compatible with the NC-PCC lower receiver, due to. The main benefit to buying 80 Percent receivers is that they can be shipped directly to your door as they are not E P ARMORY ALUMINUM JIG FOR AR15 80 LOWER. About 0% of these are Carbonate. Quick View. If the computed bandwidth is lower than the one specified on the memory module, that means that the SPD information on the module is not correctly programmed, or most likely that the CPU-Z 1. 00 Burial of Body in Churchyard after Service (DBOF & PCC) £303. Relatively new to the market with the rise of pistol caliber carbines (PCC), a lot of jigs are set up to do both the AR-15 and AR-9 platforms. Regular price: $299. Tennessee Arms Company is proud to bring to the market our newly designed TAC-9 style lower receiver. Both operate well under our testing. Five years. was therefore significantly lower than planned, with corresponding effects on volume and sales. 80% Lower Drill Bits. More than 63,000 potential poisoning cases were reported to the PCC in 2016, nearly 80 percent of which were unintentional poisonings. We offer exclusive 5D Tactical billet lower receiver designs as well as forged Mil-Spec 80% lower receivers. PCC also announced that its Burien, Wash. Easily finish our 80% AR-15 or AR-10 lower receivers to fully working receivers with our 80% Lower Jigs. Integrating the Healthcare Enterprise. LCM of 60 and 80, find the lowest common denominator (lcd) smallest multiple of two integers Least common multiple can be found by multiplying the highest exponent prime factors of 60 and 80. Lower Build Parts. 5ft PCc 5500/840 Mxh 50 5500 4520 37 122 4,7 1572 940 PRIMA LED Ex 2. The GP who reviewed my x-ray showed that my spine was abnormally straight - straightening of the lumbar lordosis on XR and suspected that I may have ankylosing spondylitis. ” Fast Free Shipping All orders over$74. cement consumption in PCC 1:4:8 and M7. 45/10mm 80% lower has more "knock down power" than any other PCC lower on the market. - Utilizing a jig and the right techniques, any 80 percent lower can be quickly transformed into a highly accurate and functional firearm. It's a TAC-9. Send to a friend. The company aims to provide all shooters with a superior quality rifle at competitive price points, while driving home lifetime value with a Lifetime Transferable Warranty and Infinite Shot Barrel Guarantee. All that is left to. Ruger PCC is a great shooter. Sale! Polymer80 80% Build Kit PF940v2 Fullsize (Glock 17) *Without LPK* $699. 5ft PCc 11000/840 Mxh 40 11000 8800 71 124 4,9 1572 940. Free NCO and solvent as TDI/MDI, safe and environmental friendly 2. 00 See details. Nemesis Defense 80% Kits Polymer80 kits 80% frames Sig P320 P365, Polymer 80 kits, 1911 kits and AR15 Kits Mens and Womens Defense Products. E-W PCC Balance Adjustment. Diameter:7 inch, Filter Material:Pleatco Advanced Point Bonded Filtration Fabric, Material Area: 80 Sq feet. Pew defines the lower class as adults whose annual household income is less than two-thirds the national median. All that is left to. 80% Lowers; what caused this PCC to fail during a match. 45 ACP rifle. The Chi-square was used to test for association with a value of P < 0. 80% arms - black anodized billet. EABC80 - 6T8 EAC91 - 6AQ6, CV137 EAF42 - 6CT7 EAM86 - 6GX8 EB34 - CV1054 EB41 6E8G, CV1347 ECH81 - 6AJ8 ECH83 - 6DS8 ECH84 - 6JX8 ECL80 - 6AB8 ECL805 - 6GV8, ECL85 ECL84. Enjoy easy and fast assembly for AR-15 and AR-308 with our 80% lower receiver kits. 5 days after 4F-PCC; the second patient developed a left lower extremity DVT 7. The lower is beautiful and one of a kind billet 7075 T-6 Aluminum (better than milspec). 40% MS STP-E STP MS STP-E STP Minimum Catalyst Advantages of STP Polymer. com with the invoice number in the subject title. Lower omega-3 fatty acid intake and status are associated with poorer cognitive function in older age: a comparison of individuals with and without cognitive impairment and Alzheimer's disease. These are 80% Gun Point Custom Glock 9mm Billet lower receivers. We match them with the highest quality buffer springs in the industry for consistent performance and extra long service life. It is the perfect upgrade to an existing weapon, or an excellent start to a new rifle or pistol build. I will be continually adding, and hope to eventually have all the wills listed from 1383 thru 1660. This receiver takes Colt Magazines : MIL-A-8625F TYPE 3 CLASS 2 Hard coat Anodized. - Utilizing a jig and the right techniques, any 80 percent lower can be quickly transformed into a highly accurate and functional firearm. Clinker 80-94 % Fly Ash, Slag, Limestone 6-20 % Gypsum 0-5 %. Only 119 patients got the intervention as intended (per protocol. Currently, PCC has around 1,600 employees across its locations. PCC-5000 Software V1. I'll replace the Trinity Force buttstock (made in china) because it wobbles. 45 ACP and 10mm Glock large frame caliber magazines. easy to clean. 1×107 Min 1×105Min. 00 miles long, had present worth costs of$157,528 by comparison. The 80 lower receiver is used to build an AR-15 at home. The geotechnical letter shall meet the requirements contained in 18E. PCC EXPANSION CONCEPT –YEARS 6 TO 10 Expansion would result in: • Lower level hall at 312,500 sf; • Upper level hall at between 300,000 and 340,000 sf. Alcoholic beverage, beer, light, low carb. 45 ACP ammunition, as there are models chambered for either cartridge. - Pre-High BP = systolic consistently 120-139 or diastolic 80-89 - Stage 1 HBP = systolic consistently 140-159 or diastolic 90-99 - Stage 2 HBP = systolic consistently 160 or over or diastolic 100 or over - Hypotension = systolic pressure lower than 90 or a pressure 25 mmHg lower than usual. This Incremental Hotfix and this article are periodically updated with new. For an upper tail area, set Upper to 5. A majority of billet lower receivers feature an integrated trigger guard, which can help add to the stiffness of the lower itself. Pleatco Free Flow cores allow for the free flow of water through the filtration fabric increasing the effectiveness of the filter. James Madison Tactcal’s first product, the 80% Generation 1 polymer lower receiver addressed several fundamental design issues associated with other polymer lowers and paved the way for the rebirth for a new design with many upgrades that addressed those issues. 00 Burial of Body in Churchyard after Service (DBOF & PCC) £303. 40 65 80 Available Yes 45 73 80 Available Yes KruKraft - Natural 20 33 Dark & Light 100% PCC Yes 22 Dark & Light 100% PCC Yes 24 41 Light 50% PCC / 50% Virgin Yes 25 41 Dark & Light 100% PCC Yes 28 Dark & Light 100% PCC Yes 30 49 Dark & Light 100% PCC Yes 33 Dark & Light 100% PCC Yes 35 57 Dark & Light 100% PCC Yes 38 Dark & Light 100% PCC Yes. 1, 1831125. I didn't catch if 80% takes bodyweight into account or not for this and the repeaters. 80 Percent AR Lowers. Phone Orders Only - Please Call 610-272-2060 To Place An Order. One of the best ways to test for urine sample adulteration or dilution is to determine certain urinary characteristics such as pH, specific gravity, oxidants/PCC, nitrite, glutaraldehyde and creatinine. The Lower Level Exhibition Hall offers 312,500 square feet of contiguous exhibit space and connects the North and West Buildings under Third Street. Respiration in cyanobacterial thylakoid membranes is interwoven with photosynthetic processes. Out of stock. All of our 80% Sig Sauer P320, 80% Glock, 80% AR 15 Lower Receivers, 80% AR 10 Lower Receivers, 80% Sig p228/229 Recievers, 80% Jig Kits and 1911 80% Frames are 100% USA Made! Everything we offer can be shipped directly to your door and does not require an FFL transfer. Medical and dental history, b. See the robot remove a finished modular PCC lower receiver, move another for additional machining, and place a new billet into the machine. 8 out of 5 stars 156 $204. function regardless of hole position in your lower receiver and also JP Anti-Walk. Beckley's board "PCC" on Pinterest. Relatively new to the market with the rise of pistol caliber carbines (PCC), a lot of jigs are set up to do both the AR-15 and AR-9 platforms. Machined from 7075-T6 Aircraft Grade Forged Aluminum - Sourced US Only! Available in; BattleScarred NiB Lower Reciever based off MILSPEC design Precision machined magazine well with beveled feed lip for easy mag swaps Compatible with standard AR-15 components and most aftermarket parts. This means that choosing the best quality will cause far less compression thanthe aptly named "Best compression" setting. Finally, I took the best tuned params of all three (RF, XGboost and LightGBM) and stacked them with 'Logistics. Driverscollection. Ryzen 5 3600 x370 stuck 0. 5, M10, M15, M20 and M25 and so more- and water cement ratio for M7. Broadly, a PCC is issued to pensioners, a LIHCC to those on lower income regardless of age and a CHSC to those above age pension age and does not qualify for any social security pension. LPF low pass filter 2400W CW 1. upper receivers. Free Shipping on Orders$35+ or Pickup In-Store and get a Pickup Discount. Most are 80. Refers back to the "Clock Modulation" I recommend setting your Speed Shift value to 64 or lower for maximum performance on this profile. Five years. AR-9 3 Piece Combo 80% Lower. Sol-Ark PCC-230 Partial Charge Carbon AGM Battery No watering required and no Off-Gassing. Evaluation of mechanical behaviour of the rubberized PCC mortar in fixed W/C ratio. Quartz crystal. AR-9 80% Billet Lower Receiver w/ LRBHO - Glock Style in the Raw features:Type: AR-9 80% Lower Receiver w/ LRBHO — milled from 7075 T6 aircraft grade aluminum billetsCaliber: Multi (will accept any 9mm,. One of our best sellers, this 12 inch guitar speaker meets the expanded frequency range often requested by the new generation of amp manufacturers. describes a pain with character of. Please Note: This is the SS80 Single Stack Frame Blank (aka 80% Lower) ONLY. As shown, 80 parts of Opacarb® A40 PCC compares with 60 parts of GCC at equal sheet gloss, but with much better optical properties and print performance. Lower Receiver Parts Kit, Two Stage Trigger. All of our 9mm lowers ship complete with mag release and ejector. Our veteran writer. MSRP: Now: $49. DS4308 Specification Sheet from Zebra: Check out the details on the corded model. 80 percent lower receiver No FFL required and All machine work that has been done is within 80 percent complete No FFL required, these are not lower receivers but are 80% complete until the. Selecting a PCC Rule for Uplink IP Packets. The map_diag is slightly different because it takes in a function that accepts a single array (remember the diagonal. The exterior has been machined to Mil-Spec for a classic look. Specifically, we propose that what German copula constructions have in common with PCC environments is that there are multiple accessible DPs in the domain of a single agreement probe, the lower of which is more featurally specified than the higher (see, e. 76 0 - 180o 90 - 270 o33 - 213 0o 120 150 120180o 150o o 90 90o 60 60o 30 30o 500 400 300 Horizontal Illuminance0o H Emax (m)(lux) 3. Why Start With an 80 Percent Lower. Answer to Verizon. Synechocystis sp. AR pistols have become quite popular over the last few years. Fiscal year is January-December. electric power sector as a result of cooler-than-normal temperatures during the second half of September and. In fact, it is one of the most reported reasons people miss work and is the second most frequent reason patients visit the doctor. Current lead time on this product is 4-6 weeks. In the fibrinogen-PCC group, 80 of 353 patients treated in the STC between 2005 and 2009 fulfilled the inclusion criteria. Refers back to the "Clock Modulation" I recommend setting your Speed Shift value to 64 or lower for maximum performance on this profile. Some heavy metals (e. In fact, this is a viable alternative to a typical AR lower that most people use for their AR pistols and SBRs. - 80 percent or 80% is a generic term that means that everything is complete on the lower except for the fire control group, safety select, trigger opening, trigger pin holes & hammer pin holes. In the event the federal standards are discontinued, the department shall, by regulation, establish income limits for lower income households for all geographic areas of the state at 80 percent of area median income, adjusted for family size and revised annually. 357 SIG, and other small frame caliber upper receiver)Magazine. The lower the better. Buffer AssemblyCarbine Action SpringReceiver End PlateCastle NutAR-15 Standard Lower Receiver Parts KitComplete Kit Includes: Standard AR-15 Pistol Grip (Black). 800 x 600mm lower bench. Firearm Discussion and Resources from AR-15, AK-47, Handguns and more! Buy, Sell, and Trade your Firearms and Gear. Reviews from PCC STRUCTURALS employees about PCC STRUCTURALS culture, salaries, benefits, work-life balance, management, job PCC STRUCTURALS Employee Reviews in San Leandro, CA. elongatus PCC 2973, Synechococcus PCC 7942, and Synechocystis PCC 6803, is 1. IHE PCC Technical Framework Supplement – Patient Plan of Care (PPOC) 205 bilateral lower lobe and right middle lobe infiltrates. WASHINGTON, October 5, 2020 – Patients’ physical and mental health is declining as nearly seven months of the pandemic take their toll, according to a new survey of primary care clinicians released today by the Larry A. Product Code: 7031-0015. Low Sulphur Contribution Low Sulphur Surcharge Low Surplur Fuel Surcharge. upper receivers. Lower Receiver Small Parts Kit, AR15 Style Out of Stock. Each commercial site in the PCC zone shall contain a minimum of 20 percent landscaped open space. Please be aware of your local laws prior to ordering. The Dirty Bird PCC (9mm /. Compatibility: GLOCK & COLT - Style Lower Receivers Carrier: MIL-SPEC 8620 Steel Material Fully Heat Treated External M-16 Style Extractor M16 (FULL-AUTO) Compatible Salt Bath Nitrided Dust Cover Compatible Weight: 14. I'm actually getting ready to start a 1911 80% and a Glock 80% from their website. 91% ↓ Mar-2019 Notes: Tolerance: subject value is within or outside calculated upper or lower limits of normally expected variations in performance. 2020, luby 3514, 0 Reversing PCC Deficiency Deficiencies The Raw Vegan Plant-Based Detoxification & Regeneration Workbook for Healing Patients. , and its 15th store overall across the Puget. Cogent Engineering: Vol. As the result, TA4058 showed lower respiratory activity in the dark and almost the same photosynthetic activity under saturated light conditions (1000 μE/m 2 /s) as compared with TA2984 (Additional file 2: Figure S3). Enjoy FAST SHIPPING and SAVE at 80-lower. The JT-9 is precision CNC-machined from solid aerospace billet aluminum. In fact, this is a viable alternative to a typical AR lower that most people use for their AR pistols and SBRs. An 80% lower receiver, also termed as A lower receiver can either be complete, stripped or an 80% receiver. It contains everything you need, including an 80% lower receiver, so you can build right away. NEW! Quick View. PCC offers the most comprehensive range of products on the market and our experienced. Compatible with all 9mm Glock-style magazines and featuring last-round bolt hold-open, these stripped lowers are machined from 7075-T6 billet aluminum and feature an all-black. PCC provides many benefits, including excellent brightness and opacity at significantly lower cost than the clay or fiber it replaces. James Madison Tactical AR15 80% Lower Receiver$ 74. 5D Tactical Router Jig Pro Universal AR-15 80% Lower Receiver Jig This item is currently on order MSRP: $199. They got the attention of the AFT for more than just an unfinished lower, otherwise there'd be way more raids than the "thousands" you claim, and the manufacturers would have gone under. 2% solid Ca(OH) 2. 00 See details. A wide variety of pcc 4 options are available to you, such as classification, grade standard, and type. The MAb capture was performed using the ÄKTA™ pcc system run in 3C PCC mode. Refers back to the "Clock Modulation". 00 Home > 9MM AR15 parts. 5 grade of concrete. AR-9 3 Piece Combo 80% Lower. Price:$70. PCC GROUP 1. Low Sulphur Contribution Low Sulphur Surcharge Low Surplur Fuel Surcharge. Sig P320 Ar Lower. Տաթեվիկ Ադումյան, Ավո Ադամյան, Ալինա Ավետիսյան, Արմեն Մարգարյան, Հովակ. Medical diagnosis is. Printable Form 1 Bio-Data Form 2020-21. 8 years and majority (80%) had tertiary education. Regular price: $299. complete lower receivers. Find quality service, superior products and helpful advice for all your home improvement needs at Lowe's. In fact, this is a viable alternative to a typical AR lower that most people use for their AR pistols and SBRs. In fact, according to the in silico simulation of PCC 6803, a higher flux of the oxidative PPP is predicted under lower light intensity in mixotrophic conditions (Shastri and Morgan 2005). FFL RESTRICTION Federal law requires this product to be transferred through a licensed FFL dealer. Add optional laser engraving for states requiring a serial number and receive a$10 discount when bought with the lower:. An 80% lower receiver, also termed as A lower receiver can either be complete, stripped or an 80% receiver. Cells were rapidly transferred into ice-cold organic solvent for instantaneous extraction of the cellular [PQ][1] plus [PQH2][2] content. 5” 9MM PCC BARREL • KVPRECISION 5” MLOK HANDGAURD • KVPRECISION PCC MUZZLEBREAK • RADIAN. Pcc pcs pns. If I lived in a state without an AWB I would be using one of the SPIKES TACTICAL LOWER RECEIVERS I already have on hand for about 1/6 of the cost. 9mm PCC: $799. AR-9 Complete Rifle. Not the cheapest 80% lower receiver but competitively priced. Sort by popularity Sort by average rating Sort by latest Sort by price: low to high Sort 9MM AR9 80% Lower Receiver with Extractor and Mag Release. The lower came with a carbine spring and buffer which i changed to an H buffer and extra power spring (the same ones that came. But consider setting to a lower number for more accurate enumeration of split candidates. Residence time selected for the process was 2. PCC matcher allows division of traffic into equal streams with ability to keep packets with specific set of options in one mark all tcp packets except tcp/80 and match these packets against first address list. , Synechocystis sp PCC 6803 and Synechococcus elongatus PCC 7942, have been engineered to produce. The Glockstore offered a 12% discount on the FM-9 PCC. of the lower receiver speaks for Itself. The main benefit to buying 80 Percent receivers is that they can be shipped directly to your door as they are not E P ARMORY ALUMINUM JIG FOR AR15 80 LOWER. Regarding coater runnability , a non-spherical particle shape and a narrow particle size distribution can lead to high performance in coated paper but also can lead to slightly increased. Blending functionality with form, all FG-9 pistols feature a large flared magwell to assist in quicker reloads, and all Upper/Lower receiver sets are mated to one another for a precise, no-rattle fitment. PCC batteries have the lowest cost per cycle of any commercially available battery type, including lithium! Lasts 7+ years @ 50% DoD / 12+ years @ 30% DoD. AR-9 Combo - 80% Lower and Upper Receiver. was therefore significantly lower than planned, with corresponding effects on volume and sales. But nonetheless, it’s an AR lower that might give the others a run for their money. The Buffalo has an exclusive on this lower. However since JP isnt selling GMR15 lowers for home builds yet. high performance. 9 °C) and a low of 49 °F (9. 5 m 3 Ca(OH) 2 added 2. Buy 80% build kit ar9 pcc 9mm colt style with extra glock mag lower: GunBroker is the largest seller of AR15 Parts Gun Parts All. It can be used on cyanide, chloride, and alkaline non-cyanide zinc to produce a sealer that will not have white corrosion in a salt spray until after 178 hours. Xabkanq - seria 80 full watch in HD. Letter to Lower Six Parents. , on Wednesday opened its newest location in Bellevue, Wash. BY shooters, FOR shooters. Cerakoted AR9 Upper/80% Lower Set (MP5 Magwell) Out of stock. Add optional laser engraving for states requiring a serial number and receive a$10 discount when bought with the lower: Custom Laser Engraving. There was nothing mentioned about a positive lock. An 80 percent lower has no parts, a complete lower does. 8 cuft (3 tractor trolly) sand consumption in pcc 1:3:6 for 100m2 & 150 mm thick pcc slab. Ryzen 5 3600 x370 stuck 0. , and its 15th store overall across the Puget. 0 Tear Tear @ g/m2 (gf) R-PCC & GCC Filler Tear S-PCC Filler Tear Particle Size Blank 30. Mystery Ranch Beartooth 80 Pack. PHONE: (386) 682-3885. True you will not be able to make 600 yard shots with it, but then again there are so few places to actually shoot that far anyways that most of us are limited to 100 yards or less which is absolutely. Setting This study was conducted at two locations of a Dutch hospital (Nieuwegein and Leidsche Rijn Utrecht). Featured Products. As the result, TA4058 showed lower respiratory activity in the dark and almost the same photosynthetic activity under saturated light conditions (1000 μE/m 2 /s) as compared with TA2984 (Additional file 2: Figure S3). PCC 80% Billet AR-9 Lower with Jig As low as $0. Coal baron and climate-change denier Robert Murray dies at 80. Best 9mm ar lower glock. q Maintenance-free operation. was therefore significantly lower than planned, with corresponding effects on volume and sales. cement consumption in PCC 1:4:8 and M7. 00: JPGMR15LR-K1: GMR-15™ Lower Receiver Kit 9mm Billet:$481. Capillary tube. We at 80lower. KPIs_met >80%. I will be continually adding, and hope to eventually have all the wills listed from 1383 thru 1660. Stripped Receivers and Complete Lowers. 45/10mm 80% lower has more "knock down power" than any other PCC lower on the market. easy to clean. AR-9 80% Billet Lower Receiver w/ LRBHO - Glock Style in the Raw features:Type: AR-9 80% Lower Receiver w/ LRBHO — milled from 7075 T6 aircraft grade aluminum billetsCaliber: Multi (will accept any 9mm,. 8 out of 5 stars 156 $204. When it comes to aluminum AR-15 80% lowers in particular, there are commonly two choices - billet and forged. Buy today or give us a call for more information about our 80 percent lower receivers for sale. All of our 80% Sig Sauer P320, 80% Glock, 80% AR 15 Lower Receivers, 80% AR 10 Lower Receivers, 80% Sig p228/229 Recievers, 80% Jig Kits and 1911 80% Frames are 100% USA Made!Everything we offer can be shipped directly to your door and does not require an FFL transfer. complete upper receivers. 7% incidence of thromboembolism after 4F-PCC administration, which is numerically lower than the reported rates of two large randomised controlled trials (RCTs) with values of 7. The patent pending Easy Jig Gen 2 Multiplatform™ is the world's easiest to use, fully universal, 80% lower jig capable of finishing AR-15, AR-9, and DPMS gen 1 pattern. Europe – Sep 2008 : Canada – Sep 2008. These Noreen 80%. to MIL-SPEC tolerances. The use of common 9mm service pistol magazines makes it an ideal choice for patrol, home defense, and cost-effective tactical training. This is helpful for beginners because there is not much recoil. 5ft PCc 8000/840 Mxh 45 8000 6430 53 121 4,8 1572 940 PRIMA LED Ex 2. 03 and Reference Manual (10/11/13) ( 3. The boat is better suited for ocean passages (vs coastal cruising) if the result of the calculation is 2. The Lightning carbon fiber handguards keep your rifle light and cool, the Fury titanium compensators keep your muzzle flat so you can dominate the competition!. Quick View. Polymer 80 Glock Pro Frame Assembly. We’ve created the FX-910U featuring our 10. An innovative achievement, the FG-9 is FALKOR Defense’s first entry into the PCC game and we are very excited to bring it to the market. The In-Line PCC process is extremely fast and therefore it can be integrated directly to paper/board production line. 7:17 PM * 80% online. Clubs & Activities. In this study, we analyzed the expression patterns of all of the genes of this cyanobacterium over two consecutive diurnal periods. Firearm Discussion and Resources from AR-15, AK-47, Handguns and more! Buy, Sell, and Trade your Firearms and Gear. – One patient developed an ischemic stroke 0. pH: This tests for the presence of acidic or alkaline adulterants in urine. Accounts & Orders. 00 See details. 5,h ow to calculate quantity of cement in PCC, in this topic we know about how to calculate quantity of cement in PCC and cement consumption in PCC 1:4:8. 9MM 80% Lower Receiver Stripped is not an FFL item. James Madison Tactical AR15 80% Lower Receiver$ 199. About 0% of these are Carbonate. The addition of both PCC and HNT nanofillers into PLA does not change the aggregation of HNT and then the fracture surface showed different zones in Figure. The New AR9 9mm 80% Percent Dedicated Lower Receiver - is the most reliable 9mm AR 80% build and only requires the milling of the rest of the fire control group chamber and the three trigger assembly holes. Smartwool® Men's 250 Merino Baselayer Bottom. 7% incidence of thromboembolism after 4F-PCC administration, which is numerically lower than the reported rates of two large randomised controlled trials (RCTs) with values of 7. PCC Buffers & Springs; 5D Tactical Router Jig PRO Multiplatform AR-15 / AR-10 80% Lower Receiver Jig This item is currently on order MSRP: $259. round,replacement for pentair clean clear 320, unicel c-7470, filbur fc-1976, pleatco pcc-80,most orders are ship same day and delivered in 3 business days. If I lived in a state without an AWB I would be using one of the SPIKES TACTICAL LOWER RECEIVERS I already have on hand for about 1/6 of the cost. Green Center, a research organization, in collaboration with the Primary Care Collaborative (PCC). While most 9mm-specific components will be compatible with the NC-PCC lower receiver, due to. 308 80% Lower with Jig Only. It contains everything you need, including an 80% lower receiver, so you can build right away. 308, AR-9, and AR-15 80 lowers and have always been thrilled with the quality and fast shipping. 357 SIG, and other small frame caliber upper receiver)Magazine. James Madison Tactical AR15 80% Lower Receiver$ 199. 80% RECEIVERS. 00 TOTAL £303. Im on the search for an alternative. Apply a Crosshatch pattern. Descubre y compra online: electrónica, moda, hogar, libros, deporte y mucho más a precios bajos en Amazon. Building your own AR from an 80 percent lower receiver is the best first time firearm building project. Instead, the one who can achieve the same education with less effort is classified as more intelligent. … The earnings for the first quarter of 2020 were likewise below our expectations and down on the previous year. BDP100 PCC 1 xLED30/830 DW L. Benefits of Crown PCC: Reduces heat of hydration, which protect cracks; Gains long-term strength in concrete; Increases workability; Suitable for constructions of dwellings or residential buildings or retaining concrete, canals, channels, & edging productions, in plastering, & mortar. OPEN fluid mediums are also useful for lowering the viscosity of Heavy Body colors and slowing the drying for detail painting using fine brushes. Low Sulphur Contribution Low Sulphur Surcharge Low Surplur Fuel Surcharge. The main benefit to buying 80 Percent receivers is that they can be shipped directly to your door as they are not E P ARMORY ALUMINUM JIG FOR AR15 80 LOWER. We have constructed a range of mutants that are impaired in several combinations of respiratory and photosynthetic electron transport complexes and have examined the relative effects on the redox state of the plastoquinone (PQ) pool by using a quinone electrode. You'd need to walk 22 minutes to burn 80 calories. The AR-15 trigger exploded view is a great guide for replacing your hammer spring. AR-15 Lower Receiver Exploded View. 99 All others just $4 Flat Rate SHOP AR15 SHOP AR10 Product Categories AR15 Parts SHOP NOW VG6 Devices COMING SOON! AR Barrels COMING SOON! AR10 Parts SHOP NOW Featured Products DISCOVER MORE. Objectives Percutaneous cervical cordotomy (PCC) is an interventional ablative procedure in the armamentarium for cancer pain treatment, but there is limited evidence to support its use. Clubs & Activities. Preparation: 1. Pew defines the lower class as adults whose annual household income is less than two-thirds the national median. Gutierrez, PCC Director, Property Tax Department. OPEN Acrylic Medium (Gloss or Matte) will lower paint viscosity to create a more fluid mixture and increase flow. WASHINGTON, October 5, 2020 – Patients’ physical and mental health is declining as nearly seven months of the pandemic take their toll, according to a new survey of primary care clinicians released today by the Larry A. Home > 9mm PCC Buffers Our 9mm AR-15 Buffers are designed to be the most effective, softest shooting 9mm Buffers available anywhere. COMPLETE UPPERS. 5” 9mm Tapered barrel, Gen 2 9mm Bolt Carrier Group, Enhanced Forged Upper Receiver, and Lightweight Gen 2 9” Aluminum handguard. 9mm AR-9 80% Lower Receiver - Glock Compatible - FDE. 99 Sure they're not; but 80's, solvent traps, and fuel filters sure make doing some criminal shit easier. Selecting a PCC Rule for Uplink IP Packets. One lower and any possible caliber upper. Internship is part of the full discount. 09) Symptomatic non-fatal PE: 10 (0. 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In relation to hematoma enlargement, Gerner et al. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.24204248189926147, "perplexity": 11458.703783055675}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-04/segments/1610703531429.49/warc/CC-MAIN-20210122210653-20210123000653-00539.warc.gz"} |
http://clay6.com/qa/29585/when-a-carbon-atom-is-linked-to-four-different-groups-it-is-said-to-be-chir | Browse Questions
# When a carbon atom is linked to four different groups it is said to be chiral carbon atom. when alpha hydrogen atom of an alkane is replaced by a functional group we get corresponding compound. Lowest molecular mass optically active ketone contians ____ carbon atoms?
$(a)\;5 \\ (b) \; 6 \\ (c) \; 8 \\ (d)\;7$
Toolbox:
• An alpha (symbol: α) hydrogen is a hydrogen atom on an alpha carbon in an organic molecule; a hydrogen atom on a beta carbon is a beta hydrogen, and so on (α, ß, γ, δ…).
• A compound capable of optical rotation is said to be optically active. All pure chiral compounds are optically active.
• A chiral molecule is a molecule that is not superimposable on its mirror image.
The lowest molecular mass optically active ketone is
$\therefore$ 6 is the correct answer.
Hence b is the correct answer.
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http://www.aanda.org/articles/aa/abs/2004/25/aa0386-03/aa0386-03.html | Free access
Issue A&A Volume 421, Number 1, July I 2004 187 - 193 Interstellar and circumstellar matter http://dx.doi.org/10.1051/0004-6361:20034386
A&A 421, 187-193 (2004)
DOI: 10.1051/0004-6361:20034386
## Observations of the Brackett decrement in the Class I source HH100 IR
B. Nisini1, S. Antoniucci2, 1 and T. Giannini1
1 INAF-Osservatorio Astronomico di Roma, 00040 Monteporzio Catone, Italy
2 Università degli Studi "Tor Vergata", via della Ricerca Scientifica 1, 00133 Roma, Italy
(Received 24 September 2003 / Accepted 3 March 2004 )
Abstract
The Brackett decrement in the Class I source HH100 IR has been observed and analyzed to set constraints on the origin of the IR HI emission in this young object. We have used both low resolution ( 800) observations of the Brackett lines from Br to Br24, and medium resolution ( 9000) spectra of the Br , Br12 and Br13 lines. The dereddened fluxes indicates that the lines remain moderately thick up to high quantum numbers. Moreover, the profiles of the three lines observed in medium resolution are all broad and nearly symmetric, with a trend for the lines at high n-number to be narrower than the Br line. With the assumption that the three lines have different optical depths and consequently trace zones at different physical depths, we interprete the observed profiles as evidence that the ionized gas velocity in the HI emitting region is increasing as we move outwards, as expected in an accelerating wind more than in an infalling gas. We have modelled the observed line ratios and velocities with a simplified model for the HI excitation from a circumstellar gas with a velocity law . Such a comparison indicates that the observations are consistent with the emission coming from a very compact region of 4-6 , where the gas has been already accelerated to velocities of the order of 200 km s -1, with an associated mass flow rate of the ionized component of the order of 10 yr -1. This implies that the observed lines should originate either from a stellar wind or from the inner part of a disk wind, providing that the disk inner truncation radius is close to the stellar surface. It is also expected that the gas ionization fraction is relatively high as testified by the high rate of ionized mass loss derived. Our analysis, however, does not resolve the problem of how to reproduce the observed symmetrical line profiles, which at present are apparently difficult to model by both wind and accretion models. This probably points to the fact that the real situation is more complicated than described in the simple model presented here.
Key words: line: formation -- stars: circumstellar matter -- stars: individual: HH100-IR -- infrared: stars -- stars: formation -- stars: winds, outflows
Offprint request: B. Nisini, [email protected] | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9648860096931458, "perplexity": 1816.2749214008652}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-44/segments/1476988721558.87/warc/CC-MAIN-20161020183841-00510-ip-10-171-6-4.ec2.internal.warc.gz"} |
https://physics.stackexchange.com/questions/150746/red-shifted-photons-lost-energy-in-which-form?noredirect=1 | # Red shifted photons lost energy in which form?
Red shifted photons lost energy in which form?
Photons which have experienced a change in frequency (red shift) due to gravity(or other red shifting affects), have necessarily lost energy, total energy is conserved.
Red shifts happen because of various causes.
there also exist blue shifts:
Conversely, a decrease in wavelength is called blueshift and is generally seen when a light-emitting object moves toward an observer or when electromagnetic radiation moves into a gravitational field.
Now on redshifts:
Some redshifts are an example of the Doppler effect, familiar in the change in the apparent pitches of sirens and frequency of the sound waves emitted by speeding vehicles. A redshift occurs whenever a light source moves away from an observer.
Energy is conserved by the motion of the source. Motion =kinetic energy . the red shifted adds to the kinetic energy of the source seen in the rest frame of the obsrver, and the blue adds to the energy of the photon again seen in the rest frame of the observer.
Another kind of redshift is cosmological redshift, which is due to the expansion of the universe, and sufficiently distant light sources (generally more than a few million light years away) show redshift corresponding to the rate of increase in their distance from Earth.
Again the motion takes up the energy balance
Finally, gravitational redshift is a relativistic effect observed in electromagnetic radiation moving out of gravitational fields.
The gravitational field picks up the balance of energy, again in the rest frame of the observer.
• Anna, I was going to ask a similar question, and this one popped up. So considering $E=mc^2$ and $E=h\nu$ fully governs the energy conservation, then for a redshifted gamma photon from the big bang, $\nu$ decreases and so does $m$ since $c$ is constant. Right? Or are there more physics involved? – docscience Apr 14 '17 at 16:04
• @docscience E=mc^2 is misleading and we no longer use it in particle physics. This m is just a mathematical description of the extra inertia and confuses things. We only work with the rest mass, ( the "length" of the four vector) and the rest mass of the photon is always zero. So when the energy decreases nu becomes smaller, equivalent to the acoustic doppler shift – anna v Apr 14 '17 at 16:21
• Thanks! So then where did the energy go if it didn't change the mass? Considering say one photon by itself as a 'system'. Was it lost to 'space-time'? I'm still researching, but can the redshift be one source of the dark energy? – docscience Apr 14 '17 at 16:28
• @docscience For conservation of energy one has to consider the relative velocity of the observer to the photon source,. – anna v Apr 14 '17 at 17:00
• But considering the source is a dead star that was formed shortly after the big bang, how could the source matter any more today? Is it because, for the photon, time is 'stopped'? – docscience Apr 14 '17 at 17:45
It seems contradictory that red shifted light has lost energy yet total energy is conserved (where did the energy go?). The trick to understanding this is knowing that the energy measured depends on the frame of reference you are measuring from.
Consider a ball flying towards you quite fast and hitting you in the head. From your perspective it has a lot of kinetic energy (and it hurt when it hit).
Now consider yourself flying along at the same speed as the ball. It's stationary compared to you and it has no kinetic energy (compared to you). It can't hit you in the head and it can't hurt you because its not moving towards you any more.
In both cases the ball is doing the same thing (and the energy in the system hasn't changed), its just your frame of reference that has changed and the same is happening with red shifted light. If you move away from light (at a fast enough speed) it will appear red shifted (less energy) and conversely if you move towards it (at a fast enough speed), it will appear blue shifted (appear to have gained energy).
Going back to the ball example, if you drive towards a ball that is flying towards you, it will hurt more (have more energy) if you drive away from it, it will hurt less (have less energy). Nothing has changed in the ball, or it's energy, it's you that has changed (e.g. you've used energy to accelerate towards or away from it).
• Technically, you can't "move away from light." You can move away from a light source, in which case, the spectrum of light that you receive from the source will be shifted toward the red from the spectrum that you expected to see based on your knowledge of the process that produced the light. – Solomon Slow Jul 27 '16 at 17:09
Energy is most definitely conserved in the case of gravitation-ally red shifted (GRS) photons. The sun is 4.6 billion years old and has energy output equal to 3.8x10+26 watts. If 1% of the energy output is lost to GRS, an enoumous quantity of energy is missing. If the lost energy were simply hanging out in the surrounding gravitational field, it should be somehow observable by now since the energy has been building up and stored for billions of years. However, that is not the case. Electromagnetic energy can not be "trapped" and somehow stored, but it can be converted to increasingly smaller frequency. All photon energy escapes EVERY gravitational field, but is red shifted. Said differently, a blue photon released from the sun is converted to many red photons as it escapes the gravitational field. Conservation of energy dictates this result. Imagine a transverse wave traveling down a stretched rope. The rope suddenly divides into two ropes. The initial wave is transformed into two smaller waves each of lower energy. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8205258846282959, "perplexity": 397.8025831557082}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570986696339.42/warc/CC-MAIN-20191019141654-20191019165154-00310.warc.gz"} |
https://nipy.org/nibabel/reference/nibabel.tmpdirs.html | # tmpdirs¶
Contexts for with statement providing temporary directories
InGivenDirectory([path]) Change directory to given directory for duration of with block InTemporaryDirectory([suffix, prefix, dir]) Create, return, and change directory to a temporary directory TemporaryDirectory([suffix, prefix, dir]) Create and return a temporary directory.
## InGivenDirectory¶
class nibabel.tmpdirs.InGivenDirectory(path=None)
Bases: object
Change directory to given directory for duration of with block
Useful when you want to use InTemporaryDirectory for the final test, but you are still debugging. For example, you may want to do this in the end:
>>> with InTemporaryDirectory() as tmpdir:
... # do something complicated which might break
... pass
But indeed the complicated thing does break, and meanwhile the InTemporaryDirectory context manager wiped out the directory with the temporary files that you wanted for debugging. So, while debugging, you replace with something like:
>>> with InGivenDirectory() as tmpdir: # Use working directory by default
... # do something complicated which might break
... pass
You can then look at the temporary file outputs to debug what is happening, fix, and finally replace InGivenDirectory with InTemporaryDirectory again.
Initialize directory context manager
Parameters
pathNone or str, optional
path to change directory to, for duration of with block. Defaults to os.getcwd() if None
__init__(path=None)
Initialize directory context manager
Parameters
pathNone or str, optional
path to change directory to, for duration of with block. Defaults to os.getcwd() if None
## InTemporaryDirectory¶
class nibabel.tmpdirs.InTemporaryDirectory(suffix='', prefix='tmp', dir=None)
Create, return, and change directory to a temporary directory
Examples
>>> import os
>>> my_cwd = os.getcwd()
>>> with InTemporaryDirectory() as tmpdir:
... _ = open('test.txt', 'wt').write('some text')
... assert os.path.isfile('test.txt')
... assert os.path.isfile(os.path.join(tmpdir, 'test.txt'))
>>> os.path.exists(tmpdir)
False
>>> os.getcwd() == my_cwd
True
__init__(suffix='', prefix='tmp', dir=None)
Initialize self. See help(type(self)) for accurate signature.
## TemporaryDirectory¶
class nibabel.tmpdirs.TemporaryDirectory(suffix='', prefix='tmp', dir=None)
Bases: object
Create and return a temporary directory. This has the same behavior as mkdtemp but can be used as a context manager.
Upon exiting the context, the directory and everthing contained in it are removed.
Examples
>>> import os
>>> with TemporaryDirectory() as tmpdir:
... fname = os.path.join(tmpdir, 'example_file.txt')
... with open(fname, 'wt') as fobj:
... _ = fobj.write('a string\n')
>>> os.path.exists(tmpdir)
False
__init__(suffix='', prefix='tmp', dir=None)
Initialize self. See help(type(self)) for accurate signature.
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https://crypto.stackexchange.com/questions/27808/authenticating-with-a-document | # Authenticating with a document
Hope you're having a nice day.
I need to implement an authentication system between a "document" (it's not exactly a document, but an object without any computing capacity, only able to store information) and a computer. The document will have some sort of information stored there by the computer, and then it will be given to an user and kept away from the computer. When the computer detects the document again, it will identify its possessor as the user to whom it was given to and authenticate it.
However, the computer isn't assumed secure, so I need the information stored there to don't be enough to replicate the document and to let us know if the computer has been modified.
On the one hand, I would like to know if the implementation I was thinking to use would be insecure: I was thinking of using RSA; I'll store the private key in the document and the public in the computer. Then, for authenticating, I'll encrypt and decrypt a random number less than N (the modulo) and see if it results the original one. This will be right, wouldn't it?
On the other hand, I would like to know if there is some research done about this topic and if there are any papers developing it. I've tried to search it by myself, but I don't know how to describe precisely without needing quite a long text. Is there any term for this type of security?
Please, don't hesitate to ask me more details in case I haven't explained myself very well. Thank you so much in advance for your help.
• While the storage device / document is attached, is the computer assumed to be secure? – SEJPM Aug 29 '15 at 20:13
• @SEJPM It is as long as we don't store any information. The calculations or operations it computes, the memory it uses or the information displayed on the screen will be assumed to be completely secure, but any information we store on a permanent file could be instantaneously accessed. – AlexGasconB Aug 29 '15 at 20:53
• So it's a legitmate threat to assume the attacker will just "steal" the credential from the storage device / document as soon as it's written and still attached? – SEJPM Aug 29 '15 at 20:56
• No, the storage device / document is assumed to be secure even when it is connected to the computer – AlexGasconB Aug 29 '15 at 21:28
Note that there are practical problems here, which may lead to side channel attacks. For example, doing anything on a general purpose computer usually involves a chance that the memory you are using hits the swap on the disk, unless you use something like mlock. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6435973644256592, "perplexity": 557.4849440572643}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046151699.95/warc/CC-MAIN-20210725143345-20210725173345-00391.warc.gz"} |
http://www.ebbworld.com/the-book-fjmlyr/how-many-unpaired-electrons-does-tellurium-have | Zinc: [Ar] 3d10 4s2. What does unpaired electrons mean? On the periodic table, tellurium sits in the sixth row below selenium. Number of Neutrons. How many valence electrons does tellurium have? then, since there is no more empty orbital at that energy level, the next electron would have … both 4s electrons are paired. How many unpaired electrons are in the neon atom? Because the p orbital is one less than 1/2 filled, it will excite an e- from the 2s orbital to the 2p to form, 1s2 2s1 2p3 which has one unpaired e- in the 2s and 3 in the 2p for a total of 4. To obtain an octet, these atoms form three covalent bonds, as in NH 3 (ammonia). It's 3d orbital is full (d^10), but you only count the 4s and 4p orbital in this case. We and our partners will store and/or access information on your device through the use of cookies and similar technologies, to display personalised ads and content, for ad and content measurement, audience insights and product development. Name: Tellurium Symbol: Te Atomic Number: 52 Atomic Mass: 127.6 amu Melting Point: 449.5 °C (722.65 K, 841.1 °F) Boiling Point: 989.8 °C (1262.95 K, 1813.64 °F) Number of Protons/Electrons: 52 Number of Neutrons: 76 Classification: Metalloid Crystal Structure: Hexagonal Density @ 293 K: 6.24 g/cm 3 Color: silverish Atomic Structure *Response times vary by subject and question complexity. Answer $\left[\mathrm{CoCl}_{4}\right]^{2-\text { has a tetrahedral shape means the d-orbital splitting pattern is as shown below. Problem: How many core electrons does an atom of bromine have? How many unpaired electrons does a cobalt ... Tellurium (Te) has an atomic radius of 143 pm and a first ionization energy of 869 kJ/mol. The electron configuration of selenium which has 34 electrons is: $$\rm 1s^2~ 2s^2~ 2sp^6~ 3s^2 ~3p^6~ 4s^2~ 3d^{10}~ 4p^4$$ To check how many unpaired electrons there are, … Thus in the excited state, the electronic configuration of Be is 1s 2 2s 1 2p 1 . Atomic Radius (pm) First Ionization Energy (kJ/mol) A. Yahoo is part of Verizon Media. You can change your choices at any time by visiting Your Privacy Controls. }}$ Electrons have an electric charge of −1 and their mass is approximately about 1/2000 the mass of a neutron or proton. Switch to. Homework Help. tellurium has 3 valence electrons. How Many Valence Electrons Does Tellurium Have. 3.7 million tough questions … Median response time is 34 minutes and may be longer for new subjects. How many unpaired electrons do you expect the complex ion \$\left[\mathrm{CoC… 02:08. of the 4 electrons in the 5p, 2 are paired and 2 are unpaired. Information about your device and internet connection, including your IP address, Browsing and search activity while using Verizon Media websites and apps. In industry, tellurium can be used in solar panels and computer chips. Here, no of bonding electrons = 8 mo of antibonding electrons = 6 so, bond order is = 1/2 (8-6) = 1. This element is shiny like a metal and can exist by itself in nature; however, tellurium is more often found combined with metals such as gold and copper. Oxygen = 1s^2, 2s^2, 2p^4 This is more energetically stable with both subshells half filled. Similarly, it is asked, how many unpaired electrons are present in the ground state Kr atom? How many unpaired electrons do you expect each complex ion to have? The full 3d and 4s orbitals can be knocked out as well because full shells/orbitals of any kind are always fully paired. In most cases, tellurium becomes an electron acceptor because taking two electrons from one atom is easier than giving six electrons to another. How many electrons does an Fe atom have in its 3d subshell and how many of those are unpaired? A selenium atom has six valence electrons. how many unpaired electrons does antimony have, Since there are no unpaired electrons, it undergoes excitation by promoting one of its 2s electron into empty 2p orbital. Helium has only one level, and two valence electrons. 76. This would be the 3d orbitals for Fe. Node 1 at orbitap (Anb'bonding 88 - Die gemeine perman . How many unpaired electrons are in the neon atom? FrontLinePRODUCTION how many electrons does tin have -film production studio audiovisuel Audio Visual fronteline tunisie location cinema mixage mastering boite prod cinematographie publicité documentaire Calcium: [Ar] 4s2. Tellurium, like every other element, wants to fill its outermost energy level with electrons. Multiple Choice < Prev 7 of 10 !!! Silicon atoms have 14 electrons and the shell structure is 2.8. *Response times vary by subject and question complexity. Median response time is 34 minutes and may be longer for new subjects. In chemistry, an unpaired electron is an electron that occupies an orbital of an atom singly, rather than as part of an electron pair. Next > course_d655721content de 1964333 18uestion rum Question Completion Status 3 5 4 10 Question 4 1. Get the detailed answer: How many unpaired electrons does a ground-state atom of sulfur have? Find out more about how we use your information in our Privacy Policy and Cookie Policy. How many valence electrons does the ground-state configuration of nitrogen have? 2 See answers sangwookbaeowif4v sangwookbaeowif4v Tellurium has 6 valence electrons. two of the three orbitals each contain one electron. So it is paramagnetic. Selenium is in the same column as oxygen, so it has the same number of valence electrons (6). The [Ar] can be ignored because we know all noble gasses have fully paired electrons. It has 4 electrons and thus it's electron configuration is 1s2 2s2. Here, chlorine has unpaired electron. p.s: the next electron would go into the last orbital. A. Paramagnetic This atom is B. Diamagnetic 2. Q: 6. Predict the properties of an atom with a greater atomic number than Te and in the same period. These Movies and Shows Can Help You Make Sense of Confusing Economic Concepts, Understanding Trustees' Duties and Responsibilities in Managing a Trust, Estate Planning 101: How to Probate a Will, The Differences Between “Defamation,” “Libel” and “Slander”. Group 5A (15) elements such as nitrogen have five valence electrons in the atomic Lewis symbol: one lone pair and three unpaired electrons. The names for positive and negative ions are pronounced CAT-eye-ons and ANN-eye-ons, respectively. - 11389472 altorians1860 altorians1860 10/20/2018 Chemistry High School Tellurium is a metalloid. tellurium number of electron shells, Tellurium atoms have 52 electrons and the electronic shell structure is [2, 8, 18, 18, 6] with Atomic Term Symbol (Quantum Numbers) 3P2. The ground state electron configuration of ground state gaseous neutral silicon is [Ne]. 141 834 C. 133 1009 D. 156 1105 59. Tellurium has a total of six valence electrons. Get the detailed answer: How many unpaired electrons does selenium have? 6. To enable Verizon Media and our partners to process your personal data select 'I agree', or select 'Manage settings' for more information and to manage your choices. (a) 0 (b) 1 (c) 2 (d) 3 (e) 4 In chemistry, an unpaired electron is an electron that occupies an orbital of an atom singly, rather than as part of an electron pair.Each atomic orbital of an atom (specified by the three quantum numbers n, l and m) has a capacity to contain two electrons (electron pair) with opposite spins.As the formation of electron pairs is often energetically favourable, either in the form of a … Personalized courses, with or without credits. 1. [2, 8, 18, 18, 6]. IN2P3 . There are five 3d orbitals, since d orbitals have 5 orientations in space. On the right, the chloride ion has 18 electrons and has a 1− charge. This group has the defining characteristic that all the component elements have 5 electrons in their outermost shell, that is 2 electrons in the s subshell and 3 unpaired electrons in the p subshell.
While resistivity is a material property, resistance is the property of an object. Each s orbital can only hold 2 electrons and since each has 2, there are are no unpaired electrons. How many unpaired electrons does an atom of carbon have in its ground state? Having six valence electrons, tellurium tends to hold on to its electrons rather tightly. This atom is A. Paramagnetic B. Diamagnetic 2. How many valence electrons does tellurium have? Helium for example has two electrons. The levels go all the way up to 7, and within each one, is a sublevel, s, p, d, and f. s has 2 electrons, p has 6, d has 10, and f has 14. Booster Classes. Of the two valance shell orbitals (2s and 2p) there two unpaired electrons. To facilitate our understanding of how valence electrons interact, a simple way of representing those valence electrons would be useful. What is the difference in the number of spin-up versus spin-down electrons for ground-state tellurium? In this oxidation, a molecule of hydrogen gas is ionized to two electrons and two protons. two unpaired electrons . Your dashboard and recommendations. Tellurium: [Kr] 4d10 5s2 5p4. therefore, in the Lewis structure two atoms will be on one side, while the third is alone. Iodine-132 that closely follows tellurium decay disappears within three weeks. 3s 2. E - 1. Furthermore, how many unpaired electrons does carbon have? At the end of these seven weeks, only remains Iodine-131 that has decreased 38 times. it has 2 unpaired electrons. He = 1s^2. Group of answer choices Be Li Xe C F A: In the given question we have to identify the smallest atom in the group of atoms mention. How many unpaired electrons do you expect the complex ion [CoCl4]2- to have if it is a tetrahedral shape? The Cookies Statement is part of our Privacy Policy. Who Is Alexa — and What Does Amazon's Virtual Assistant Say About the Future of AI? we're looking at the 3p subshell which has three orbitals. Electron Configuration. Why Is the Keystone XL Pipeline Still So Disputed? On the periodic table, selenium is element number 34; it is located in group 16 below oxygen and sulfur. How many unpaired electrons are in the calcium atom? 424 People Used More Information ›› Having six valence electrons, tellurium tends to hold on to its electrons rather tightly. 4. How many unpaired electrons does the ground-state configuration of chromium have? of the 5 electrons in the 4p, 4 are paired and 1 is unpaired. Arsenic has 3 unpaired p electrons when neutral Explanation: Arsenic's electron configfuration is [Ar] 3d¹⁰ 4s² 4p³. On the left, the chlorine atom has 17 electrons. Predict the number of unpaired electrons in the following, complex ions: (a)… 01:14. Evaluate dx and select a right chice from the given choices 15 B 3+0 6 O Q 24 5 3 2 15 X 3 +C 8 O 15 24 o R . 2. Bromine: [Ar] 3d10 4s2 4p5. 167 813 B. Each atomic orbital of an atom (specified by the three quantum numbers n, l and m) has a capacity to contain two electrons (electron pair) with opposite spins. Tellurium, like every other element, wants to fill its outermost energy level with electrons. How many unpaired electrons does a ground state atom of rhodium Rh have A 0 B 2 from CHEM 1311 at University of Texas, Dallas Shell structure (Electrons per energy level). Home. Unpaired electrons may be found in a set of orbitals that is not filled. a. Zero. Therefore, tellurium has 1 unpaired electron. both 4s electrons are paired. Tellurium's properties are intermediate between those of metals and nonmetals, making it a metalloid. 5. They are therefore 3 electrons short of filling their outermost electron shell in their non-ionized state. In most cases, tellurium becomes an electron acceptor because taking two electrons from one atom is easier than giving six electrons to another. Tellurium belongs to the oxygen family, also called the chalcogens. This atom is This atom is A. Paramagnetic B. Diamagnetic 1. How Many Unpaired Electrons Does Selenium Have In Its 4p Orbital? Q: Identify the smallest atom. 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https://chemistry.stackexchange.com/questions/54072/chemical-reagent-test-sensitive-at-low-concentrations | # Chemical Reagent Test sensitive at low concentrations
Would there be a spot test/tests that can detect either/both of the following molecules at low concentrations?
The likely concentrations are in the $10{-}\pu{50 mg/L}$ range in an aqueous solution. Ideally, I'd want something that does not need an exotic/expensive instrument. e.g. a color change or precipitation or conductivity/pH change.
The background interference: The sample is Terrific Broth which has the following composition:
$\pu{12 g}$ Bacto tryptone
$\pu{24 g}$ Bacto yeast extract
$\pu{4 mL}$ Glycerol
$\pu{100 mL}\ \pu{0.17M}\ \ce{KH2PO4}$ and $\pu{0.72M}\ \ce{K2HPO4}$, sterile, to be prepared separately from the tryptone, yeast extract, and glycerol solution.
• Any sort of such a spot test would depend heavily on what else might be in the solution. So what other "stuff" could be in the water? I wouldn't expect either of those molecules to be very water soluble. – MaxW Jun 22 '16 at 19:28
• Thanks @MaxW I've added info about what else could be in the sample. And yes you are right these are not very water soluble although at the low conc. I am expecting they very well might be. This is a conc. of less that 0.01%. – curious_cat Jun 22 '16 at 19:34
• In any case, I want to brainstorm possible test options. At which point I can test them out on control samples of the broth to see what reaction I get. – curious_cat Jun 22 '16 at 19:36
• >Bacto yeast extract || yeah, forget about any meaningful spectroscopy for such low concentrations with this unholy mix in the media. Theoretically speaking, a highly selective molecular recognition agent such as specifically tailored antibody may work, but the R&D required would be quite costly, so unless your needs do not exceed thousands of samples, it is not even worth considering. Other than thatn, GS/GSMS is your best bet. – permeakra Jun 22 '16 at 19:39
• @permeakra Thanks for the insight. That's what I feared. GCMS works well, just that it is slow as number of samples scale. – curious_cat Jun 23 '16 at 2:37 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6121903657913208, "perplexity": 2147.6804057284276}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046151699.95/warc/CC-MAIN-20210725143345-20210725173345-00093.warc.gz"} |
https://meangreenmath.com/tag/tangent/ | Engaging students: Deriving the double angle formulas for sine, cosine, and tangent
In my capstone class for future secondary math teachers, I ask my students to come up with ideas for engaging their students with different topics in the secondary mathematics curriculum. In other words, the point of the assignment was not to devise a full-blown lesson plan on this topic. Instead, I asked my students to think about three different ways of getting their students interested in the topic in the first place.
I plan to share some of the best of these ideas on this blog (after asking my students’ permission, of course).
This student submission comes from my former student Daniel Adkins. His topic, from Precalculus: deriving the double angle formulas for sine, cosine, and tangent.
How does this topic extend what your students should have already learned?
A major factor that simplifies deriving the double angle formulas is recalling the trigonometric identities that help students “skip steps.” This is true especially for the Sum formulas, so a brief review of these formulas in any fashion would help students possibly derive the equations on their own in some cases. Listed below are the formulas that can lead directly to the double angle formulas.
A list of the formulas that students can benefit from recalling:
• Sum Formulas:
• sin(a+b) = sin(a)cos(b) + cos(a)sin(b)
• cos(a+b) = cos(a)cos(b) – sin(a)sin(b)
• tan(a+b) = [tan(a) +tan(b)] / [1-tan(a)tan(b)]
• Pythagorean Identity:
• Sin2 (a) + Cos2(a) = 1
This leads to the next topic, an activity for students to attempt the equation on their own.
How could you as a teacher create an activity or project that involves your topic?
I’m a firm believer that the more often a student can learn something of their own accord, the better off they are. Providing the skeletal structure of the proofs for the double angle formulas of sine, cosine, and tangent might be enough to help students reach the formulas themselves. The major benefit of this is that, even though these are simple proofs, they have a lot of variance on how they may be presented to students and how “hands on” the activity can be.
I have an example worksheet demonstrating this with the first two double angle formulas attached below. This is in extremely hands on format that can be given to students with the formulas needed in the top right corner and the general position where these should be inserted. If needed the instructor could take this a step further and have the different Pythagorean Identities already listed out (I.e. Cos2(a) = 1 – Sin2(a), Sin2(a) = 1 – Cos2(a)) to emphasize that different formats could be needed. This is an extreme that wouldn’t take students any time to reach the conclusions desired. Of course a lot of this information could be dropped to increase the effort needed to reach the conclusion.
A major benefit with this also is that even though they’re simple, students will still feel extremely rewarded from succeeding on this paper on their own, and thus would be more intrinsically motivated towards learning trig identities.
How can Technology be used to effectively engage students with this topic?
When it comes to technology in the classroom, I tend to lean more on the careful side. I know me as a person/instructor, and I know I can get carried away and make a mess of things because there was so much excitement over a new toy to play with. I also know that the technology can often detract from the actual math itself, but when it comes to trigonometry, and basically any form of geometric mathematics, it’s absolutely necessary to have a visual aid, and this is where technology excels.
The Wolfram Company has provided hundreds of widgets for this exact purpose, and below, you’ll find one attached that demonstrates that sin(2a) appears to be equal to its identity 2cos(a)sin(a). This is clearly not a rigorous proof, but it will help students visualize how these formulas interact with each other and how they may be similar. The fact that it isn’t rigorous may even convince students to try to debunk it. If you can make a student just irritated enough that they spend a few minutes trying to find a way to show you that you’re wrong, then you’ve done your job in that you’ve convinced them to try mathematics for a purpose.
After all, at the end of the day, it doesn’t matter how you begin your classroom, or how you engage your students, what matters is that they are engaged, and are willing to learn.
Wolfram does have a free cdf reader for its demonstrations on this website: http://demonstrations.wolfram.com/AVisualProofOfTheDoubleAngleFormulaForSine/
References
My Favorite One-Liners: Part 106
In this series, I’m compiling some of the quips and one-liners that I’ll use with my students to hopefully make my lessons more memorable for them.
Years ago, when I first taught Precalculus at the college level, I was starting a section on trigonometry by reminding my students of the acronym SOHCAHTOA for keeping the trig functions straight:
$\sin \theta = \displaystyle \frac{\hbox{Opposite}}{\hbox{Hypotenuse}}$,
$\cos \theta = \displaystyle \frac{\hbox{Adjacent}}{\hbox{Hypotenuse}}$,
$\tan \theta = \displaystyle \frac{\hbox{Opposite}}{\hbox{Adjacent}}$.
At this point, one of my students volunteered that a previous math teacher had taught her an acrostic to keep these straight: Some Old Hippie Caught Another Hippie Tripping On Acid.
Needless to say, I’ve been passing this pearl of wisdom on to my students ever since.
My Favorite One-Liners: Part 69
In this series, I’m compiling some of the quips and one-liners that I’ll use with my students to hopefully make my lessons more memorable for them.
This story, that I’ll share with my Precalculus students, comes from Fall 1996, my first semester as a college professor. I was teaching a Precalculus class, and the topic was vectors. I forget the exact problem (believe me, I wish I could remember it), but I was going over the solution of a problem that required finding $\tan^{-1}(7)$. I told the class that I had worked this out ahead of time, and that the approximate answer was $82^o$. Then I used that angle for whatever I needed it for and continued until obtaining the eventual solution.
(By the way, I now realize that I was hardly following best practices by computing that angle ahead of time. Knowing what I know now, I should have brought a calculator to class and computed it on the spot. But, as a young professor, I was primarily concerned with getting the answer right, and I was petrified of making a mistake that my students could repeat.)
After solving the problem, I paused to ask for questions. One student asked a good question, and then another.
Then a third student asked, “How did you know that $\tan^{-1}(7)$ was $82^o$?
The class immediately erupted… some with laughter, some with disbelief. (I had a terrific rapport with those students that semester; part of the daily atmosphere was the give-and-take with any number of exuberant students.) One guy in the front row immediately challenged me: “Oh yeah? Then what’s $\tan^{-1}(9)$?
I started to stammer, “Uh, um…”
“Aha!” they said. “He’s faking it.” They start pulling out their calculators.
Then I thought as fast as I could. Then I realized that I knew that $\tan 82^o \approx 7$, thanks to my calculation prior to class. I also knew that $\displaystyle \lim_{x \to 90^-} \tan x = \infty$ since the graph of $y = \tan x$ has a vertical asymptote at $x = \pi/2 = 90^o$. So the solution to $\tan x = 9$ had to be somewhere between $82^o$ and $90^o$.
So I took a total guess. “$84^o$,” I said, faking complete and utter confidence.
Wouldn’t you know it, I was right. (The answer is about $83.66^o$.)
In stunned disbelief, the guy who asked the question asked, “How did you do that?”
I was reeling in shock that I guessed correctly. But I put on my best poker face and answered, “I told you, I had it memorized.” And then I continued with the next example. For the rest of the semester, my students really thought I had it memorized.
To this day, this is my favorite stunt that I ever pulled off in front of my students.
Engaging students: Defining sine, cosine and tangent in a right triangle
In my capstone class for future secondary math teachers, I ask my students to come up with ideas for engaging their students with different topics in the secondary mathematics curriculum. In other words, the point of the assignment was not to devise a full-blown lesson plan on this topic. Instead, I asked my students to think about three different ways of getting their students interested in the topic in the first place.
I plan to share some of the best of these ideas on this blog (after asking my students’ permission, of course).
This student submission comes from my former student Loc Nguyen. His topic, from Geometry: defining sine, cosine and tangent in a right triangle.
What interesting (i.e., uncontrived) word problems using this topic can your students do now?
There are many real world applications that involve in this topic and I will incorporate some problems in real life to engage the students. Suppose I have a classroom that has the shape of rectangular prism. I will begin my lesson by challenging the students to find the height of the classroom and of course I will award them with something cool. I believe this will ignite students’ curiosity and excitement to participate into the problem. In the process of finding the height, I will gradually introduce the concept of right triangle trigonometry. The students will learn the relationship of ratios of the sides in the triangle. Eventually, the students will realize that they need this concept for finding the height of the classroom. I will pose some guiding questions to drive them toward the solution. Such questions could be: what can I measure? Can we measure the angle from our eyes to the opposite corner of the ceiling point? What formula will help me to find the height?
After this problem I will provide them many different real world problems to practice such as:
How can this topic be used in your students’ future courses in mathematics or science?
Knowing how to compute sine, cosine or tangent in the right triangle will help students a lot when they get to higher level math or other science class, especially Physics. In higher level math, students will always have the chance to encounter this concept. For example, in Pre-Calculus, the students will likely learn about polar system. This requires students to have the strong fundamental understandings of sine, cosine and tangent in a right triangle. Students will be asked to convert from the Cartesian system to polar system, or vice versa. If they do not grasp the ideas of this topic, they will eventually encounter huge obstacles in future. In science, especially physics, the students will learn a lot about the motions of an objects. This will involve concepts of force, velocity, speed, momentum. The students will need to understand the how to compute sine, cosine and tangent in the right triangle so that they can easily know how to approach the problems in physics.
How can technology (YouTube, Khan Academy [khanacademy.org], Vi Hart, Geometers Sketchpad, graphing calculators, etc.) be used to effectively engage students with this topic?
This website, https://www.geogebra.org/material/simple/id/48148 , can be a great tool for the students to understand the relationships of the sides in the right triangle. The website creates an activity for students to explore the ratios of the sides such as AC/BC, AC/AB, and BC/AB. The students will observe the changes of the ratios based on the changes of theta and side BC which is the hypotenuse. At this point, the students will be introduced the name of each side of the right triangle which corresponds to theta such as opposite, adjacent and hypotenuse. This activity allows the students to visualize what happens to the triangle when we change the angle or its side lengths. The students will then explore the activity to find interesting facts about the side ratios. I will pose some questions to help the students understand the relationships of side ratios. Such questions could be: What type of triangle is it? Tell me how the triangle changes as we change the hypotenuse or angle. If we know one side length and the angle, how can we find the other side lengths? Those questions allow me to introduce the terms sine, cosine, and tangent in the right triangle.
References
https://en.wikibooks.org/wiki/High_School_Trigonometry/Applications_of_Right_Triangle_Trigonometry
https://www.geogebra.org/material/simple/id/48148
SOHCAHTOA
Years ago, when I first taught Precalculus at the college level, I was starting a section on trigonometry by reminding my students of the acronym SOHCAHTOA for keeping the trig functions straight:
$\sin \theta = \displaystyle \frac{\hbox{Opposite}}{\hbox{Hypotenuse}}$,
$\cos \theta = \displaystyle \frac{\hbox{Adjacent}}{\hbox{Hypotenuse}}$,
$\tan \theta = \displaystyle \frac{\hbox{Opposite}}{\hbox{Adjacent}}$.
At this point, one of my students volunteered that a previous math teacher had taught her an acrostic to keep these straight: Some Old Hippie Caught Another Hippie Tripping On Acid.
Needless to say, I’ve been passing this pearl of wisdom on to my students ever since.
10 Secret Trig Functions Your Math Teachers Never Taught You
Students in trigonometry are usually taught about six functions:
$\sin \theta, \cos \theta, \tan \theta, \cot \theta, \sec \theta, \csc \theta$
I really enjoyed this article about trigonometric functions that were used in previous generations but are no longer taught today, like $\hbox{versin} \theta$ and $\hbox{havercosin} \theta$:
http://blogs.scientificamerican.com/roots-of-unity/10-secret-trig-functions-your-math-teachers-never-taught-you/
Naturally, Math With Bad Drawings had a unique take on this by adding a few more suggested functions to the list. My favorites:
The antiderivative of 1/(x^4+1): Index
I’m doing something that I should have done a long time ago: collecting a series of posts into one single post. The following links comprised my series on the computation of
$\displaystyle \int \frac{dx}{x^4+1}$
Part 1: Introduction.
Part 2: Factoring the denominator using De Moivre’s Theorem.
Part 3: Factoring the denominator using the difference of two squares.
Part 4: The partial fractions decomposition of the integrand.
Part 5: Partial evaluation of the resulting integrals.
Part 6: Evaluation of the remaining integrals.
Part 7: An apparent simplification using a trigonometric identity.
Part 8: Discussion of the angles for which the identity holds.
Part 9: Proof of the angles for which the identity holds.
Part 10: Implications for using this identity when computing definite integrals. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 24, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6708088517189026, "perplexity": 764.9133641774924}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-17/segments/1524125947033.92/warc/CC-MAIN-20180424174351-20180424194351-00005.warc.gz"} |
https://www.physicsforums.com/threads/potentiometer-resistance.186595/ | # Potentiometer Resistance
1. Sep 23, 2007
### tanky322
1. The problem statement, all variables and given/known data
In the circuit below, the wiper divides the potentiometer resistance between $$\alpha R$$ and$$\ (1- alpha R)$$, 0 $$\leq$$$$\alpha$$ $$\geq 1$$. Find Vo / Vs
2. Relevant equations
KVL
KCL
3. The attempt at a solution
Im thinking that the Pot. Resistance will be R +(1-$$\alpha$$)R. Then to find the voltage (R +(1-$$\alpha$$)R)I
#### Attached Files:
• ###### Schematic1.JPG
File size:
13.5 KB
Views:
76
2. Sep 23, 2007
### mgb_phys
You can ignore the resistance of the main part of the pot to ground that is below the wiper because it is in parallel with a short circuit.
The resitance of the pot is simply, R - alphaR = R(1-alpha)
3. Sep 24, 2007
### tanky322
(($$\Sigma$$R)/I)Vs
Sorry about the formatting, I need to learn how to use the system.
Thanks
Andrew
Similar Discussions: Potentiometer Resistance | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7677794098854065, "perplexity": 4049.8056363287615}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-34/segments/1502886103270.12/warc/CC-MAIN-20170817111816-20170817131816-00504.warc.gz"} |
http://math.stackexchange.com/questions/95213/branch-point-what-makes-a-closed-loop-around-it-special/95352 | # Branch point-what makes a closed loop around it special?
I am having difficulty understanding the concept of a branch point of a multifunction. It is typically explained as follows:branch point is a point such that the function is discontinuous when going around an arbitrarily small circuit around this point. What I am unable to understand is what is special about the set of points encircling this particular point? If I have a closed loop somewhere in the plane, the function is not multivalued on this loop. But if I translate this to enclose this point, then the function becomes multivalued. Why? I initially thought it might be because if this branch point is my reference point then as I run over the loop I am running over the values 0 to 2$pi$. But if I move my reference point to somewhere inside the loop this still remains true over any closed loop. Please can someone help? A similar question was asked but unfortunately did not receive ny replies. OP was advised to read the wiki page which I have.
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Perhaps the difficulty is in the definition of multifunction, rather than branch point. Have you seen a rigorous definition of this? – Zhen Lin Dec 30 '11 at 16:16
(Disclaimer: What follows is non-standard and was dreamt up after thinking about anafunctors the whole day.)
First of all, let me define some notions. I will assume familiarity with elementary point set topology.
Definition. Let $X$ and $Y$ be topological spaces. A continuous relation between $X$ and $Y$ is a triple $(R, \sigma, \tau)$ consisting of a topological space $R$ and continuous maps $\sigma : R \to X$ and $\tau : R \to Y$.
This is a generalisation of the usual notion of a relation between two sets: indeed, recall that a relation on $X$ and $Y$ is just a subset $R \subseteq X \times Y$, and any such subset is automatically equipped with continuous projection maps to $X$ and $Y$.
Also, just as a function is a special kind of relation in set theory, a continuous function is a special kind of continuous relation: every continuous function $f : X \to Y$ induces a continuous relation $(X, \textrm{id}, f)$, and every continuous relation $(R, \sigma, \tau)$ with $\sigma : R \to X$ a homeomorphism induces a continuous function $\tau \circ \sigma^{-1} : X \to Y$.
Example. Let $X = Y = \mathbb{C}$, and let $R = \{ (x, y) \in \mathbb{C}^2 : y = x^2 \}$. Then $R$ together with the canonical projections makes a continuous relation between $\mathbb{C}$ and $\mathbb{C}$. Note that it is not a function, since the projection $(x, y) \mapsto x$ is not a homeomorphism here. (It's not even a bijection!) We will later see that it is a branched continuous multifunction, however.
Definition. An unbranched continuous multifunction $F : X \nrightarrow Y$ is a continuous relation $(R, \sigma, \tau)$ such that $\sigma$ is surjective and a local homeomorphism.
This makes $R$ into what is called an espace étalé over $X$. Here are some general facts about such spaces:
Proposition. Let $\sigma : R \to X$ be a surjective local homeomorphism.
1. For each point $x$ in $X$, the fibre $R_x = \sigma^{-1} \{ x \}$ is non-empty and has the discrete topology.
2. The map $\sigma : R \to X$ has the path lifting property: i.e. if $\gamma : [0, 1] \to X$ be a continuous path and $x = \gamma (0)$, then for any $\tilde{x}$ in $R_x$, there is a unique continuous path $\tilde{\gamma} : [0, 1] \to R$ such that $\sigma \circ \tilde{\gamma} = \gamma$ and $\tilde{\gamma}(0) = x$.
Example. Let $X = \mathbb{C} \setminus \{ 0 \}$, $Y = \mathbb{C}$, and define $$R = \{ (x, y) \in \mathbb{C}^2 : x \ne 0, y = x^2 \}$$ Let $\sigma : R \to X$, $\tau : R \to Y$ be the first and second projections, respectively. Obviously, $\sigma$ is surjective, and with a little work it can be shown that $\sigma$ is a local homeomorphism: after all, that's exactly what it means to be able to take a square root locally. Thus, $(R, \sigma, \tau)$ is an unbranched multifunction.
Now, let $\gamma : [0, 1] \to X$ be the unit circle, with $\gamma(0) = 1$. Explicitly, $$\gamma (t) = \exp (2 \pi t i)$$ One easily verifies that $(1, 1) \in R$, so by the path lifting property there is a unique path $\tilde{\gamma} : [0, 1] \to R$ lying over $\gamma$. Here we are lucky and there is an explicit formula: $$\tilde{\gamma} (t) = (\exp (2 \pi t i), \exp (\pi t i))$$
What is ‘the value’ of the multifunction along this path? It is just $\tau \circ \tilde{\gamma}$, of course. But one immediately sees that \begin{align} \tau(\tilde{\gamma}(0)) & = +1 \newline \tau(\tilde{\gamma}(1)) & = -1 \end{align} So, even though $\tilde{\gamma}$ is a lift of the closed loop $\gamma$, $\tilde{\gamma}$ itself is not a closed loop! It is precisely this which leads to the phenomenon you allude to in your question: in more advanced terms, this is simply the observation that the induced map on fundamental groups $\sigma_* : \pi_1(R, \tilde{x}) \to \pi_1(R, x)$ is not an isomorphism. When this happens, we say $\sigma$ has non-trivial monodromy.
Example. More generally, there is a notion of a covering space of $X$. If $R$ is a covering space of $X$ with covering map $\sigma : R \to X$, then $(R, \sigma, \textrm{id})$ is a unbranched continuous multifunction $X \nrightarrow R$.
Finally, let us define the notions in question themselves.
Definition. A (branched) continuous multifunction $F : X \nrightarrow Y$ is a continuous relation $(R, \sigma, \tau)$ with the following properties:
1. The map $\sigma$ is surjective.
2. The set $$U = \{ x \in X : \sigma \text{ is a local homeomorphism at each point in the fibre } R_x \}$$ is a dense open subset of $X$.
3. The restriction $(\hat{R}, \sigma |_{\hat{R}}, \tau |_{\hat{R}})$ is an unbranched continuous multifunction, where $\hat{R} = \sigma^{-1} U$.
A ramification point is a point $\tilde{x}$ of $R$ such that $\sigma$ fails to be a local homeomorphism. A branch point is a point $x$ of $R$ such that there is a ramification point $\tilde{x}$ with $\sigma(\tilde{x}) = x$. Observe that, in the above notation, $X \setminus U$ is precisely the set of branch points of $F$: so we are stipulating that the set of branch points is nowhere dense.
Proposition. If $F : X \nrightarrow Y$ is a branched continuous multifunction, and $x$ is not a branch point, then there is an open neighbourhood $U$ and a map $\phi : U \to R$ such that $\sigma \circ \phi$ is the identity on $U$, and $\tau \circ \phi : U \to Y$ is a genuine continuous function. We say $\phi$ is a local section of $F$.
This immediately follows from the fact that $\sigma$ is a local homeomorphism above $x$.
Example. Returning to the first example, where $X = Y = \mathbb{C}$ and $$R = \{ (x, y) \in \mathbb{C}^2 : y = x^2 \}$$ we see that $(R, \sigma, \tau)$ defines a branched multifunction: the only ramification point is $(0, 0)$, so the only branch point is $0$, and $U = \mathbb{C} \setminus \{ 0 \}$ is indeed an open dense subset of $\mathbb{C}$.
Now, what does this have to do with closed loops? Well, here we have to specialise a bit. One property of $\mathbb{C}$ is that it is locally simply connected: indeed, for every open neighbourhood $U$ containing a point $x$, there is a disc centred at $x$ contained in $U$. The monodromy theorem this implies that, for any surjective local homeomorphism $\sigma : R \to U$, any lift of any sufficiently small closed loop in $U$ through $\sigma$ must again be a closed loop.
Let us suppose $\sigma$ has the property that every fibre $R_x$ is finite. Thus, if $x$ is not a branch point, for every point $\tilde{x}$ in the fibre $R_x$, there is an open neighbourhood $V_{\tilde{x}}$ of $\tilde{x}$ such that $\sigma |_{V_{\tilde{x}}} : V_{\tilde{x}} \to U_{\tilde{x}}$ is a homeomorphism, where $U_{\tilde{x}}$ is an open neighbourhood of $x$. Set $$U = \bigcap_{\tilde{x} \in R_x} U_{\tilde{x}}$$ Since $R_x$ is finite, $U$ is open, and by construction $\sigma^{-1} U$ will be homeomorphic to $R_x \times U$. But $U$ must contain an open disc $D$ centred on $x$, and it is clear that $\sigma^{-1} D$ will be homeomorphic to a disjoint union of finitely many open discs. It follows that every closed loop contained in $D$ must lift to a closed loop in $\sigma^{-1} D$. Therefore, by contraposition, if $x$ is a point such that there are arbitrarily small closed loops encircling $x$ which do not lift to closed loops, $x$ must be a branch point.
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I don't know if this will help you but here is an example.
Think about $\sqrt{z}$ going around the origin counter-clockwise, $z=re^{i\theta}$, defining $\sqrt{r}$ to be the positive square root or the non-negative real number $r$. Then it's easy to define $\sqrt{z}$ for $0\leq\theta<2\pi, r\geq0$, we have $\sqrt{re^{i\theta}}=\sqrt{r}e^{i\theta/2}$. But coming back around to the positive real axis, there is a problem. We have already defined$\sqrt{z}$ there as the positive square root of $r$, but the function, trying to continue it, wants to take the value $\sqrt{r}e^{\pi i}=-\sqrt{r}$. So you have to go to the concept of a Riemann surface or a multivalued function or whatever.
One can unambiguously define $\sqrt{z}$ on any simply connected open set not containing the origin (essentially because one can choose values for the argument of $\sqrt{z}$, a way of halving the angle). But near zero, you can't do this continuously in a single valued way as we saw above.
- | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 1, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9774467945098877, "perplexity": 94.26683518669023}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-06/segments/1422122192267.50/warc/CC-MAIN-20150124175632-00191-ip-10-180-212-252.ec2.internal.warc.gz"} |
https://thecuriousastronomer.wordpress.com/2011/11/14/test-of-latex-equations/ | Feeds:
Posts
This is just a post to try and figure out what is going wrong with the horizontal alignment of Latex text. For example $360^{\circ}$ doesn’t seem to align correctly with the text either side of it. What happens if I just put in $F=ma$ into the line? That comes out above the text too. Clearly something is wrong!! What about $P^{2} \propto a^{3}$, how does this come out? Is $a$ the semi-major axis? Yes it is, and $P$ is the period of the orbit. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 5, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.990380585193634, "perplexity": 254.61117566230038}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-34/segments/1502886105086.81/warc/CC-MAIN-20170818175604-20170818195604-00456.warc.gz"} |
https://www.studypug.com/ca/ca-pat-test-prep/what-are-polynomials | # Characteristics of polynomials
### Characteristics of polynomials
A polynomial consists of constants, variables and exponents. Polynomials are named based on the number of terms they have. Polynomials with 1 term are called monomials. Those with 2 terms are called binomials, and the ones with 3 terms are called trinomials.
#### Lessons
• Introduction
a)
What is a polynomial?
• Review on Variables, Coefficients, and Expressions
• What are Monomials, Binomials, and Trinomials?
• What are the Degree, Leading Term, and Constant term of a polynomial?
• Name polynomials based on degree: Quadratic, Cubic, Quartic, Quintic, etc.
b)
How to find the degree of a polynomial?
• 1.
Determine the number of terms and the name for each of the expression.
a)
$- 5{y^2}$
b)
$2{x^2} + 4x + 6$
c)
$- 7.3$
d)
$y^3 + ay + nx - x^2$
• 2.
Find the degree and number of terms for each of the following expression.
a)
$2xy - 3{y^2} + 6$
b)
$4{a^3} + a$
c)
$- 4$
• 3.
Write the expression for each set of the algebra tiles.
a)
b)
c)
• 4.
Peter wants to buy some comic books and magazines. A bookstore sells comic books for $12 each and magazines for$8 each.
a)
Write an expression to represent the money Peter needs to spend on both comic books and magazines.
b)
How much does Peter need to spend if he wants 9 comic books and 3 magazines?
c)
Write a new expression for Peter's expenditure on books if the bookstore raises the price of a comic book to $15 and a magazine to$10. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 7, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2135682851076126, "perplexity": 1754.5431468487466}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-17/segments/1618039388763.75/warc/CC-MAIN-20210420091336-20210420121336-00424.warc.gz"} |
http://www.mat.ufpb.br/posgrad/index.php/eventos/2-uncategorised/11-encontro-de-controle-de-edp-s-e-aplicacoes | Departamento de Matemática - UFPB
João Pessoa - PB - 24 e 25 de Julho de 2014
--------
---------
Programação
Quinta Feira - 24/07/2014
10:30 - 11:15 - Eduardo Cerpa (UTFSM - Chile) 11:15 - 12:00 - Juan Límaco (UFF) ------------------------------ 15:30 - 16:15 - Diego Souza (US - Espanha) 16:15 - 17:00 - Alberto Mercado (UTFSM - Chile)
Sexta Feira - 25/07/2014
10:30 - 11:15 - Valéria Domingos Cavalcanti (UEM) 11:15 - 12:00 - Luz de Teresa (UNAM - México)
Títulos e resumos das palestras
Eduardo Cerpa (UTFSM-Chile)
Título: Feedback control of the Korteweg-de Vries equation
Resumo: This talk is concerned with the stabilization problem of the Korteweg-de Vries equation posed on a bounded interval. The design of some feedback control laws stabilizing the system is presented. Three different tools are used: a damping method, a Gramian-based approach and the Backstepping method.
Juan Límaco (UFF)
Titulo: Controle do N-dimensional modelo de Ladyzhenskaya-Smagorinsky con N-1 controles escalares em um domínio de control arbitrário.
Resumo: Nesta palestra abordaremos o estudo da controlabilidade nula local do modelo de Ladyzhenskaya-Smagorinsky com N-1 controles escalares, sendo arbitrário o domínio onde atua o controle. Nós seguimos as ideias de um recente trabalho de Carreño-Guerrero que trata deste problema para o sistema de Navier-Stokes com N-1 controles.
------------
Diego Souza (US-Espanha)
Título: On the uniform control of some $\alpha$-models
Resumo: This talk deals with the internal and boundary controllability results of the so called Leray-$\alpha$ model of turbulence. This is a regularized variant of the Navier-Stokes system ($\alpha$ is a small positive parameter), the usual transport term is regularized with an operator that depends on $\alpha$. In the limit $\alpha$ tending to $0^+$, we find the classical Navier-Stokes system. The main aim of the talk is to prove that the Leray-$\alpha$ systems are locally null controllable, with controls uniformly bounded with respect to $\alpha$. We also prove that, if the initial data are sufficiently small, the controls converge as $\alpha \to 0^+$ to a null control of the Navier-Stokes equations. We also discuss some additional results and open questions.
Título: Controllability of Schrodinger equations.
Resumo: The problem of controllability of Schrödinger equations by means of a control supported in a region not satisfying the classical geometrical control condition is addressed. We prove the controllability of a cascade system of two linear n-dimensional Schrödinger equations, using one single control. The proof is based on Carleman estimates with degenerate weights.
------------
Valéria Domingos Cavalcanti (UEM)
Título: Intrinsic decay rate estimates for the wave equation with competing viscoelastic and frictional dissipative effects
Resumo: Wave equation defined on a compact Riemannian manifold (M; g) subject to a combination of locally distributed viscoelastic and frictional dissipations is discussed. The viscoelastic dissipation is active on the support of a(x) while the frictional damping affects the portion of the manifold quantified by the support of b(x) where both a(x) and b(x) are smooth functions. Assuming that a(x) + b(x) > 0 for all x in M and that the relaxation function satisfies certain nonlinear differential inequality, it is shown that the solutions decay according to the law dictated by the decay rates corresponding to the slowest damping. In the special case when the viscoelastic effect is active on the entire domain and the frictional dissipation is differentiable at the origin, then the overall decay rates are dictated by the viscoelasticity.
Luz de Teresa (UNAM- México)
Título: A Carleman inequality for a one dimensional degenerate parabolic equations with first order terms.
Resumo: In this conference we present a Carleman estimate for the one dimensional degenerate parabolic equation: v_t + (x^{\alpha}v_{x})_{x} =F_0+(x^{\beta/2}F_1)_x, (x,t) \in (0,1) \times (0,T), where $\alpha \in [0,2)$, $\beta \ge \alpha$ and $F_0,F_1\in L^2((0,1)\times (0,T))$ and give some controllability consequences.
---
Todas as palestras acontecerão na sala de reuniões do Departamento de Matemática
Para mais informações contactar:
Fágner Araruna - Este endereço de email está protegido contra piratas. Necessita ativar o JavaScript para o visualizar.
Enrique Fernández Cara - Este endereço de email está protegido contra piratas. Necessita ativar o JavaScript para o visualizar.
---------------
Apoio: | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7942715883255005, "perplexity": 6191.060059919848}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-30/segments/1500549426086.44/warc/CC-MAIN-20170726082204-20170726102204-00163.warc.gz"} |
https://is.tuebingen.mpg.de/publications/4115 | # Analyzing microarray data using quantitative association rules
#### ei
Motivation: We tackle the problem of finding regularities in microarray data. Various data mining tools, such as clustering, classification, Bayesian networks and association rules, have been applied so far to gain insight into gene-expression data. Association rule mining techniques used so far work on discretizations of the data and cannot account for cumulative effects. In this paper, we investigate the use of quantitative association rules that can operate directly on numeric data and represent cumulative effects of variables. Technically speaking, this type of quantitative association rules based on half-spaces can find non-axis-parallel regularities. Results: We performed a variety of experiments testing the utility of quantitative association rules for microarray data. First of all, the results should be statistically significant and robust against fluctuations in the data. Next, the approach should be scalable in the number of variables, which is important for such high-dimensional data. Finally, the rules should make sense biologically and be sufficiently different from rules found in regular association rule mining working with discretizations. In all of these dimensions, the proposed approach performed satisfactorily. Therefore, quantitative association rules based on half-spaces should be considered as a tool for the analysis of microarray gene-expression data.
Author(s): Georgii, E. and Richter, L. and Rückert, U. and Kramer, S. Journal: Bioinformatics Volume: 21 Number (issue): Suppl. 2 Pages: 123-129 Year: 2005 Month: September Day: 0 Department(s): Empirical Inference Bibtex Type: Article (article) Digital: 0 DOI: 10.1093/bioinformatics/bti1121 Language: en Organization: Max-Planck-Gesellschaft School: Biologische Kybernetik Links: BibTex @article{4115, title = {Analyzing microarray data using quantitative association rules}, author = {Georgii, E. and Richter, L. and R{\"u}ckert, U. and Kramer, S.}, journal = {Bioinformatics}, volume = {21}, number = {Suppl. 2}, pages = {123-129}, organization = {Max-Planck-Gesellschaft}, school = {Biologische Kybernetik}, month = sep, year = {2005}, month_numeric = {9} } | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.16115762293338776, "perplexity": 4258.325366495593}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-34/segments/1596439737645.2/warc/CC-MAIN-20200808110257-20200808140257-00098.warc.gz"} |
https://www.hackmath.net/en/math-problem/6618 | # Intercept with axis
F(x)=log(x+4)-2, what is the x intercept
Result
x = 96
#### Solution:
$F(x)=\log(x+4)-2 \ \\ F(x)=0 \ \\ \log(x+4)-2=0 \ \\ \log(x+4)=2 \ \\ x+4=10^2 \ \\ x=10^2 - 4=96$
Our examples were largely sent or created by pupils and students themselves. Therefore, we would be pleased if you could send us any errors you found, spelling mistakes, or rephasing the example. Thank you!
Leave us a comment of this math problem and its solution (i.e. if it is still somewhat unclear...):
Showing 1 comment:
Dr Math
Assuming "log" is the decadic logarithm (log with base 10)
Tips to related online calculators
Do you have a linear equation or system of equations and looking for its solution? Or do you have quadratic equation?
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We want to prove the sentence: If the natural number n is divisible by six, then n is divisible by three. From what assumption we started?
8. Logarithm
Determine the number whose decimal logarithm is -3.8.
9. Log
Calculate value of expression log |3 +7i +5i2| .
10. Elements
If the number of elements is decreased by two the number of permutations is decreased 30 times. How many elements are?
11. Ball game
Richard, Denis and Denise together scored 932 goals. Denis scored 4 goals over Denise but Denis scored 24 goals less than Richard. Determine the number of goals for each player.
12. Linear imaginary equation
Given that ? "this is z star" Find the value of the complex number z.
13. Solve 3
Solve quadratic equation: (6n+1) (4n-1) = 3n2
14. Difference AP 4
Calculate the difference of the AP if a1 = 0.5, a2 + a3 = -1.1
15. Roots
Determine the quadratic equation absolute coefficient q, that the equation has a real double root and the root x calculate: ?
16. Forest nursery
In the forest nursery after winter, they found that 1/10 stems died out of them. For them, they land 193 new spruces. How many spruces are in the forest nursery?
17. Null points
Calculate the roots of the equation: ? | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 1, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7098907828330994, "perplexity": 2942.486485753703}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-16/segments/1585370518767.60/warc/CC-MAIN-20200403220847-20200404010847-00342.warc.gz"} |
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# 9. Input and Output
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## 9.1 Introduction to Input and Output
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## 9.2 Files
A file is simply an area on a particular storage device which contains data or text. Files on the disks are figuratively grouped into "directories". A directory is just a list of files. Commands which deal with files are: save, load, loadfile, stringout, batch, demo, writefile, closefile, and appendfile.
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## 9.3 Definitions for Input and Output
System variable: __
__ is the input expression currently being evaluated. That is, while an input expression expr is being evaluated, __ is expr.
__ is assigned the input expression before the input is simplified or evaluated. However, the value of __ is simplified (but not evaluated) when it is displayed.
__ is recognized by batch, but not by load.
Examples:
(%i1) print ("I was called as", __); I was called as print(I was called as, __) (%o1) print(I was called as, __) (%i2) foo (__); (%o2) foo(foo(__)) (%i3) g (x) := (print ("Current input expression =", __), 0); (%o3) g(x) := (print("Current input expression =", __), 0) (%i4) [aa : 1, bb : 2, cc : 3]; (%o4) [1, 2, 3] (%i5) (aa + bb + cc)/(dd + ee + g(x)); cc + bb + aa Current input expression = -------------- g(x) + ee + dd 6 (%o5) ------- ee + dd
System variable: _
_ is the most recent input expression (e.g., %i1, %i2, %i3, ...).
_ is assigned the input expression before the input is simplified or evaluated. However, the value of _ is simplified (but not evaluated) when it is displayed.
_ is recognized by batch, but not by load.
Examples:
(%i1) 13 + 29; (%o1) 42 (%i2) :lisp $_ ((MPLUS) 13 29) (%i2) _; (%o2) 42 (%i3) sin (%pi/2); (%o3) 1 (%i4) :lisp$_ ((%SIN) ((MQUOTIENT) $%PI 2)) (%i4) _; (%o4) 1 (%i5) a: 13$ (%i6) b: 29$(%i7) a + b; (%o7) 42 (%i8) :lisp$_ ((MPLUS) $A$B) (%i8) _; (%o8) b + a (%i9) a + b; (%o9) 42 (%i10) ev (_); (%o10) 42
System variable: %
% is the output expression (e.g., %o1, %o2, %o3, ...) most recently computed by Maxima, whether or not it was displayed.
% is recognized by batch, but not by load.
System variable: %%
In compound statements, namely block, lambda, or (s_1, ..., s_n), %% is the value of the previous statement. For example,
block (integrate (x^5, x), ev (%%, x=2) - ev (%%, x=1)); block ([prev], prev: integrate (x^5, x), ev (prev, x=2) - ev (prev, x=1));
yield the same result, namely 21/2.
A compound statement may comprise other compound statements. Whether a statement be simple or compound, %% is the value of the previous statement. For example,
block (block (a^n, %%*42), %%/6)
yields 7*a^n.
Within a compound statement, the value of %% may be inspected at a break prompt, which is opened by executing the break function. For example, at the break prompt opened by
block (a: 42, break ())$entering %%; yields 42. At the first statement in a compound statement, or outside of a compound statement, %% is undefined. %% is recognized by both batch and load. See also %. Option variable: %edispflag Default value: false When %edispflag is true, Maxima displays %e to a negative exponent as a quotient. For example, %e^-x is displayed as 1/%e^x. Function: %th (i) The value of the i'th previous output expression. That is, if the next expression to be computed is the n'th output, %th (m) is the (n - m)'th output. %th is useful in batch files or for referring to a group of output expressions. For example, block (s: 0, for i:1 thru 10 do s: s + %th (i))$
sets s to the sum of the last ten output expressions.
%th is recognized by batch, but not by load.
Special symbol: "?"
As prefix to a function or variable name, ? signifies that the name is a Lisp name, not a Maxima name. For example, ?round signifies the Lisp function ROUND. See Lisp and Maxima for more on this point.
The notation ? word (a question mark followed a word, separated by whitespace) is equivalent to describe ("word").
Option variable: absboxchar
Default value: !
absboxchar is the character used to draw absolute value signs around expressions which are more than one line tall.
Option variable: file_output_append
Default value: false
file_output_append governs whether file output functions append or truncate their output file. When file_output_append is true, such functions append to their output file. Otherwise, the output file is truncated.
save, stringout, and with_stdout respect file_output_append. Other functions which write output files do not respect file_output_append. In particular, plotting and translation functions always truncate their output file, and tex and appendfile always append.
Function: appendfile (filename)
Appends a console transcript to filename. appendfile is the same as writefile, except that the transcript file, if it exists, is always appended.
closefile closes the transcript file opened by appendfile or writefile.
Function: batch (filename)
Reads Maxima expressions from filename and evaluates them. batch searches for filename in the list file_search_maxima. See file_search.
filename comprises a sequence of Maxima expressions, each terminated with ; or $. The special variable % and the function %th refer to previous results within the file. The file may include :lisp constructs. Spaces, tabs, and newlines in the file are ignored. A suitable input file may be created by a text editor or by the stringout function. batch reads each input expression from filename, displays the input to the console, computes the corresponding output expression, and displays the output expression. Input labels are assigned to the input expressions and output labels are assigned to the output expressions. batch evaluates every input expression in the file unless there is an error. If user input is requested (by asksign or askinteger, for example) batch pauses to collect the requisite input and then continue. It may be possible to halt batch by typing control-C at the console. The effect of control-C depends on the underlying Lisp implementation. batch has several uses, such as to provide a reservoir for working command lines, to give error-free demonstrations, or to help organize one's thinking in solving complex problems. batch evaluates its argument. batch has no return value. See also load, batchload, and demo. Function: batchload (filename) Reads Maxima expressions from filename and evaluates them, without displaying the input or output expressions and without assigning labels to output expressions. Printed output (such as produced by print or describe) is displayed, however. The special variable % and the function %th refer to previous results from the interactive interpreter, not results within the file. The file cannot include :lisp constructs. batchload returns the path of filename, as a string. batchload evaluates its argument. See also batch and load. Function: closefile () Closes the transcript file opened by writefile or appendfile. Function: collapse (expr) Collapses expr by causing all of its common (i.e., equal) subexpressions to share (i.e., use the same cells), thereby saving space. (collapse is a subroutine used by the optimize command.) Thus, calling collapse may be useful after loading in a save file. You can collapse several expressions together by using collapse ([expr_1, ..., expr_n]). Similarly, you can collapse the elements of the array A by doing collapse (listarray ('A)). Function: concat (arg_1, arg_2, ...) Concatenates its arguments. The arguments must evaluate to atoms. The return value is a symbol if the first argument is a symbol and a Maxima string otherwise. concat evaluates its arguments. The single quote ' prevents evaluation. (%i1) y: 7$ (%i2) z: 88$(%i3) concat (y, z/2); (%o3) 744 (%i4) concat ('y, z/2); (%o4) y44 A symbol constructed by concat may be assigned a value and appear in expressions. The :: (double colon) assignment operator evaluates its left-hand side. (%i5) a: concat ('y, z/2); (%o5) y44 (%i6) a:: 123; (%o6) 123 (%i7) y44; (%o7) 123 (%i8) b^a; y44 (%o8) b (%i9) %, numer; 123 (%o9) b Note that although concat (1, 2) looks like a number, it is a Maxima string. (%i10) concat (1, 2) + 3; (%o10) 12 + 3 Function: sconcat (arg_1, arg_2, ...) Concatenates its arguments into a string. Unlike concat, the arguments do not need to be atoms. The result is a Lisp string. (%i1) sconcat ("xx[", 3, "]:", expand ((x+y)^3)); (%o1) xx[3]:y^3+3*x*y^2+3*x^2*y+x^3 Function: disp (expr_1, expr_2, ...) is like display but only the value of the arguments are displayed rather than equations. This is useful for complicated arguments which don't have names or where only the value of the argument is of interest and not the name. Function: dispcon (tensor_1, tensor_2, ...) Function: dispcon (all) Displays the contraction properties of its arguments as were given to defcon. dispcon (all) displays all the contraction properties which were defined. Function: display (expr_1, expr_2, ...) Displays equations whose left side is expr_i unevaluated, and whose right side is the value of the expression centered on the line. This function is useful in blocks and for statements in order to have intermediate results displayed. The arguments to display are usually atoms, subscripted variables, or function calls. See also disp. (%i1) display(B[1,2]); 2 B = X - X 1, 2 (%o1) done Option variable: display2d Default value: true When display2d is false, the console display is a string (1-dimensional) form rather than a display (2-dimensional) form. Option variable: display_format_internal Default value: false When display_format_internal is true, expressions are displayed without being transformed in ways that hide the internal mathematical representation. The display then corresponds to what inpart returns rather than part. Examples: User part inpart a-b; A - B A + (- 1) B A - 1 a/b; - A B B 1/2 sqrt(x); sqrt(X) X 4 X 4 X*4/3; --- - X 3 3 Function: dispterms (expr) Displays expr in parts one below the other. That is, first the operator of expr is displayed, then each term in a sum, or factor in a product, or part of a more general expression is displayed separately. This is useful if expr is too large to be otherwise displayed. For example if P1, P2, ... are very large expressions then the display program may run out of storage space in trying to display P1 + P2 + ... all at once. However, dispterms (P1 + P2 + ...) displays P1, then below it P2, etc. When not using dispterms, if an exponential expression is too wide to be displayed as A^B it appears as expt (A, B) (or as ncexpt (A, B) in the case of A^^B). Option variable: error_size Default value: 10 error_size modifies error messages according to the size of expressions which appear in them. If the size of an expression (as determined by the Lisp function ERROR-SIZE) is greater than error_size, the expression is replaced in the message by a symbol, and the symbol is assigned the expression. The symbols are taken from the list error_syms. Otherwise, the expression is smaller than error_size, and the expression is displayed in the message. See also error and error_syms. Example: The size of U, as determined by ERROR-SIZE, is 24. (%i1) U: (C^D^E + B + A)/(cos(X-1) + 1)$ (%i2) error_size: 20$(%i3) error ("Example expression is", U); Example expression is errexp1 -- an error. Quitting. To debug this try debugmode(true); (%i4) errexp1; E D C + B + A (%o4) -------------- cos(X - 1) + 1 (%i5) error_size: 30$ (%i6) error ("Example expression is", U); E D C + B + A Example expression is -------------- cos(X - 1) + 1 -- an error. Quitting. To debug this try debugmode(true);
Option variable: error_syms
Default value: [errexp1, errexp2, errexp3]
In error messages, expressions larger than error_size are replaced by symbols, and the symbols are set to the expressions. The symbols are taken from the list error_syms. The first too-large expression is replaced by error_syms[1], the second by error_syms[2], and so on.
If there are more too-large expressions than there are elements of error_syms, symbols are constructed automatically, with the n-th symbol equivalent to concat ('errexp, n).
Function: expt (a, b)
If an exponential expression is too wide to be displayed as a^b it appears as expt (a, b) (or as ncexpt (a, b) in the case of a^^b).
expt and ncexpt are not recognized in input.
Option variable: exptdispflag
Default value: true
When exptdispflag is true, Maxima displays expressions with negative exponents using quotients, e.g., X^(-1) as 1/X.
Function: filename_merge (path, filename)
Constructs a modified path from path and filename. If the final component of path is of the form ###.something, the component is replaced with filename.something. Otherwise, the final component is simply replaced by filename.
Function: file_search (filename)
Function: file_search (filename, pathlist)
file_search searches for the file filename and returns the path to the file (as a string) if it can be found; otherwise file_search returns false. file_search (filename) searches in the default search directories, which are specified by the file_search_maxima, file_search_lisp, and file_search_demo variables.
file_search first checks if the actual name passed exists, before attempting to match it to "wildcard" file search patterns. See file_search_maxima concerning file search patterns.
The argument filename can be a path and file name, or just a file name, or, if a file search directory includes a file search pattern, just the base of the file name (without an extension). For example,
file_search ("/home/wfs/special/zeta.mac"); file_search ("zeta.mac"); file_search ("zeta");
all find the same file, assuming the file exists and /home/wfs/special/###.mac is in file_search_maxima.
file_search (filename, pathlist) searches only in the directories specified by pathlist, which is a list of strings. The argument pathlist supersedes the default search directories, so if the path list is given, file_search searches only the ones specified, and not any of the default search directories. Even if there is only one directory in pathlist, it must still be given as a one-element list.
The user may modify the default search directories. See file_search_maxima.
file_search is invoked by load with file_search_maxima and file_search_lisp as the search directories.
Option variable: file_search_maxima
Option variable: file_search_lisp
Option variable: file_search_demo
These variables specify lists of directories to be searched by load, demo, and some other Maxima functions. The default values of these variables name various directories in the Maxima installation.
The user can modify these variables, either to replace the default values or to append additional directories. For example,
file_search_maxima: ["/usr/local/foo/###.mac", "/usr/local/bar/###.mac"]$replaces the default value of file_search_maxima, while file_search_maxima: append (file_search_maxima, ["/usr/local/foo/###.mac", "/usr/local/bar/###.mac"])$
appends two additional directories. It may be convenient to put such an expression in the file maxima-init.mac so that the file search path is assigned automatically when Maxima starts.
Multiple filename extensions and multiple paths can be specified by special "wildcard" constructions. The string ### expands into the sought-after name, while a comma-separated list enclosed in curly braces {foo,bar,baz} expands into multiple strings. For example, supposing the sought-after name is neumann,
"/home/{wfs,gcj}/###.{lisp,mac}"
expands into /home/wfs/neumann.lisp, /home/gcj/neumann.lisp, /home/wfs/neumann.mac, and /home/gcj/neumann.mac.
Function: file_type (filename)
Returns a guess about the content of filename, based on the filename extension. filename need not refer to an actual file; no attempt is made to open the file and inspect the content.
The return value is a symbol, either object, lisp, or maxima. If the extension starts with m or d, file_type returns maxima. If the extension starts with l, file_type returns lisp. If none of the above, file_type returns object.
Function: grind (expr)
Option variable: grind
The function grind prints expr to the console in a form suitable for input to Maxima. grind always returns done.
When expr is the name of a function or macro, grind prints the function or macro definition instead of just the name.
See also string, which returns a string instead of printing its output. grind attempts to print the expression in a manner which makes it slightly easier to read than the output of string.
When the variable grind is true, the output of string and stringout has the same format as that of grind; otherwise no attempt is made to specially format the output of those functions. The default value of the variable grind is false.
grind can also be specified as an argument of playback. When grind is present, playback prints input expressions in the same format as the grind function. Otherwise, no attempt is made to specially format input expressions.
grind evaluates its argument.
Examples:
(%i1) aa + 1729; (%o1) aa + 1729 (%i2) grind (%); aa+1729$(%o2) done (%i3) [aa, 1729, aa + 1729]; (%o3) [aa, 1729, aa + 1729] (%i4) grind (%); [aa,1729,aa+1729]$ (%o4) done (%i5) matrix ([aa, 17], [29, bb]); [ aa 17 ] (%o5) [ ] [ 29 bb ] (%i6) grind (%); matrix([aa,17],[29,bb])$(%o6) done (%i7) set (aa, 17, 29, bb); (%o7) {17, 29, aa, bb} (%i8) grind (%); {17,29,aa,bb}$ (%o8) done (%i9) exp (aa / (bb + 17)^29); aa ----------- 29 (bb + 17) (%o9) %e (%i10) grind (%); %e^(aa/(bb+17)^29)$(%o10) done (%i11) expr: expand ((aa + bb)^10); 10 9 2 8 3 7 4 6 (%o11) bb + 10 aa bb + 45 aa bb + 120 aa bb + 210 aa bb 5 5 6 4 7 3 8 2 + 252 aa bb + 210 aa bb + 120 aa bb + 45 aa bb 9 10 + 10 aa bb + aa (%i12) grind (expr); bb^10+10*aa*bb^9+45*aa^2*bb^8+120*aa^3*bb^7+210*aa^4*bb^6 +252*aa^5*bb^5+210*aa^6*bb^4+120*aa^7*bb^3+45*aa^8*bb^2 +10*aa^9*bb+aa^10$ (%o12) done (%i13) string (expr); (%o13) bb^10+10*aa*bb^9+45*aa^2*bb^8+120*aa^3*bb^7+210*aa^4*bb^6\ +252*aa^5*bb^5+210*aa^6*bb^4+120*aa^7*bb^3+45*aa^8*bb^2+10*aa^9*\ bb+aa^10 (%i14) cholesky (A):= block ([n : length (A), L : copymatrix (A), p : makelist (0, i, 1, length (A))], for i thru n do for j : i thru n do (x : L[i, j], x : x - sum (L[j, k] * L[i, k], k, 1, i - 1), if i = j then p[i] : 1 / sqrt(x) else L[j, i] : x * p[i]), for i thru n do L[i, i] : 1 / p[i], for i thru n do for j : i + 1 thru n do L[i, j] : 0, L)$(%i15) grind (cholesky); cholesky(A):=block( [n:length(A),L:copymatrix(A), p:makelist(0,i,1,length(A))], for i thru n do (for j from i thru n do (x:L[i,j],x:x-sum(L[j,k]*L[i,k],k,1,i-1), if i = j then p[i]:1/sqrt(x) else L[j,i]:x*p[i])), for i thru n do L[i,i]:1/p[i], for i thru n do (for j from i+1 thru n do L[i,j]:0),L)$ (%o15) done (%i16) string (fundef (cholesky)); (%o16) cholesky(A):=block([n:length(A),L:copymatrix(A),p:makelis\ t(0,i,1,length(A))],for i thru n do (for j from i thru n do (x:L\ [i,j],x:x-sum(L[j,k]*L[i,k],k,1,i-1),if i = j then p[i]:1/sqrt(x\ ) else L[j,i]:x*p[i])),for i thru n do L[i,i]:1/p[i],for i thru \ n do (for j from i+1 thru n do L[i,j]:0),L)
Option variable: ibase
Default value: 10
Integers entered into Maxima are interpreted with respect to the base ibase.
ibase may be assigned any integer between 2 and 35 (decimal), inclusive. When ibase is greater than 10, the numerals comprise the decimal numerals 0 through 9 plus capital letters of the alphabet A, B, C, ..., as needed. The numerals for base 35, the largest acceptable base, comprise 0 through 9 and A through Y.
Option variable: inchar
Default value: %i
inchar is the prefix of the labels of expressions entered by the user. Maxima automatically constructs a label for each input expression by concatenating inchar and linenum. inchar may be assigned any string or symbol, not necessarily a single character.
(%i1) inchar: "input"; (%o1) input (input1) expand ((a+b)^3); 3 2 2 3 (%o1) b + 3 a b + 3 a b + a (input2)
Function: ldisp (expr_1, ..., expr_n)
Displays expressions expr_1, ..., expr_n to the console as printed output. ldisp assigns an intermediate expression label to each argument and returns the list of labels.
(%i1) e: (a+b)^3; 3 (%o1) (b + a) (%i2) f: expand (e); 3 2 2 3 (%o2) b + 3 a b + 3 a b + a (%i3) ldisp (e, f); 3 (%t3) (b + a) 3 2 2 3 (%t4) b + 3 a b + 3 a b + a (%o4) [%t3, %t4] (%i4) %t3; 3 (%o4) (b + a) (%i5) %t4; 3 2 2 3 (%o5) b + 3 a b + 3 a b + a
Function: ldisplay (expr_1, ..., expr_n)
Displays expressions expr_1, ..., expr_n to the console as printed output. Each expression is printed as an equation of the form lhs = rhs in which lhs is one of the arguments of ldisplay and rhs is its value. Typically each argument is a variable. ldisp assigns an intermediate expression label to each equation and returns the list of labels.
(%i1) e: (a+b)^3; 3 (%o1) (b + a) (%i2) f: expand (e); 3 2 2 3 (%o2) b + 3 a b + 3 a b + a (%i3) ldisplay (e, f); 3 (%t3) e = (b + a) 3 2 2 3 (%t4) f = b + 3 a b + 3 a b + a (%o4) [%t3, %t4] (%i4) %t3; 3 (%o4) e = (b + a) (%i5) %t4; 3 2 2 3 (%o5) f = b + 3 a b + 3 a b + a
Option variable: linechar
Default value: %t
linechar is the prefix of the labels of intermediate expressions generated by Maxima. Maxima constructs a label for each intermediate expression (if displayed) by concatenating linechar and linenum. linechar may be assigned any string or symbol, not necessarily a single character.
Intermediate expressions might or might not be displayed. See programmode and labels.
Option variable: linel
Default value: 79
linel is the assumed width (in characters) of the console display for the purpose of displaying expressions. linel may be assigned any value by the user, although very small or very large values may be impractical. Text printed by built-in Maxima functions, such as error messages and the output of describe, is not affected by linel.
Option variable: lispdisp
Default value: false
When lispdisp is true, Lisp symbols are displayed with a leading question mark ?. Otherwise, Lisp symbols are displayed with no leading mark.
Examples:
(%i1) lispdisp: false$(%i2) ?foo + ?bar; (%o2) foo + bar (%i3) lispdisp: true$ (%i4) ?foo + ?bar; (%o4) ?foo + ?bar
Evaluates expressions in filename, thus bringing variables, functions, and other objects into Maxima. The binding of any existing object is clobbered by the binding recovered from filename. To find the file, load calls file_search with file_search_maxima and file_search_lisp as the search directories. If load succeeds, it returns the name of the file. Otherwise load prints an error message.
load works equally well for Lisp code and Maxima code. Files created by save, translate_file, and compile_file, which create Lisp code, and stringout, which creates Maxima code, can all be processed by load. load calls loadfile to load Lisp files and batchload to load Maxima files.
See file_search for more detail about the file search mechanism.
Evaluates Lisp expressions in filename. loadfile does not invoke file_search, so filename must include the file extension and as much of the path as needed to find the file.
loadfile can process files created by save, translate_file, and compile_file. The user may find it more convenient to use load instead of loadfile.
loadfile quotes its argument, so filename must be a literal string, not a string variable. The double-single-quote operator defeats quotation.
Default value: true
loadprint tells whether to print a message when a file is loaded.
• When loadprint is true, always print a message.
• When loadprint is false, never print a message.
Option variable: obase
Default value: 10
obase is the base for integers displayed by Maxima.
obase may be assigned any integer between 2 and 35 (decimal), inclusive. When obase is greater than 10, the numerals comprise the decimal numerals 0 through 9 plus capital letters of the alphabet A, B, C, ..., as needed. The numerals for base 35, the largest acceptable base, comprise 0 through 9, and A through Y.
Option variable: outchar
Default value: %o
outchar is the prefix of the labels of expressions computed by Maxima. Maxima automatically constructs a label for each computed expression by concatenating outchar and linenum. outchar may be assigned any string or symbol, not necessarily a single character.
(%i1) outchar: "output"; (output1) output (%i2) expand ((a+b)^3); 3 2 2 3 (output2) b + 3 a b + 3 a b + a (%i3)
Option variable: packagefile
Default value: false
Package designers who use save or translate to create packages (files) for others to use may want to set packagefile: true to prevent information from being added to Maxima's information-lists (e.g. values, functions) except where necessary when the file is loaded in. In this way, the contents of the package will not get in the user's way when he adds his own data. Note that this will not solve the problem of possible name conflicts. Also note that the flag simply affects what is output to the package file. Setting the flag to true is also useful for creating Maxima init files.
Option variable: pfeformat
Default value: false
When pfeformat is true, a ratio of integers is displayed with the solidus (forward slash) character, and an integer denominator n is displayed as a leading multiplicative term 1/n.
(%i1) pfeformat: false$(%i2) 2^16/7^3; 65536 (%o2) ----- 343 (%i3) (a+b)/8; b + a (%o3) ----- 8 (%i4) pfeformat: true$ (%i5) 2^16/7^3; (%o5) 65536/343 (%i6) (a+b)/8; (%o6) 1/8 (b + a)
Function: print (expr_1, ..., expr_n)
Evaluates and displays expr_1, ..., expr_n one after another, from left to right, starting at the left edge of the console display.
The value returned by print is the value of its last argument. print does not generate intermediate expression labels.
See also display, disp, ldisplay, and ldisp. Those functions display one expression per line, while print attempts to display two or more expressions per line.
To display the contents of a file, see printfile.
(%i1) r: print ("(a+b)^3 is", expand ((a+b)^3), "log (a^10/b) is", radcan (log (a^10/b)))$3 2 2 3 (a+b)^3 is b + 3 a b + 3 a b + a log (a^10/b) is 10 log(a) - log(b) (%i2) r; (%o2) 10 log(a) - log(b) (%i3) disp ("(a+b)^3 is", expand ((a+b)^3), "log (a^10/b) is", radcan (log (a^10/b)))$ (a+b)^3 is 3 2 2 3 b + 3 a b + 3 a b + a log (a^10/b) is 10 log(a) - log(b)
Function: tcl_output (list, i0, skip)
Function: tcl_output (list, i0)
Function: tcl_output ([list_1, ..., list_n], i)
Prints elements of a list enclosed by curly braces { }, suitable as part of a program in the Tcl/Tk language.
tcl_output (list, i0, skip) prints list, beginning with element i0 and printing elements i0 + skip, i0 + 2 skip, etc.
tcl_output (list, i0) is equivalent to tcl_output (list, i0, 2).
tcl_output ([list_1, ..., list_n], i) prints the i'th elements of list_1, ..., list_n.
Examples:
(%i1) tcl_output ([1, 2, 3, 4, 5, 6], 1, 3)${1.000000000 4.000000000 } (%i2) tcl_output ([1, 2, 3, 4, 5, 6], 2, 3)$ {2.000000000 5.000000000 } (%i3) tcl_output ([3/7, 5/9, 11/13, 13/17], 1)${((RAT SIMP) 3 7) ((RAT SIMP) 11 13) } (%i4) tcl_output ([x1, y1, x2, y2, x3, y3], 2)$ {$Y1$Y2 $Y3 } (%i5) tcl_output ([[1, 2, 3], [11, 22, 33]], 1)$ {SIMP 1.000000000 11.00000000 }
Prints expr_1, ..., expr_n, then reads one expression from the console and returns the evaluated expression. The expression is terminated with a semicolon ; or dollar sign $. See also readonly. (%i1) foo: 42$ (%i2) foo: read ("foo is", foo, " -- enter new value.")$foo is 42 -- enter new value. (a+b)^3; (%i3) foo; 3 (%o3) (b + a) Function: readonly (expr_1, ..., expr_n) Prints expr_1, ..., expr_n, then reads one expression from the console and returns the expression (without evaluation). The expression is terminated with a ; (semicolon) or$ (dollar sign).
(%i1) aa: 7$(%i2) foo: readonly ("Enter an expression:"); Enter an expression: 2^aa; aa (%o2) 2 (%i3) foo: read ("Enter an expression:"); Enter an expression: 2^aa; (%o3) 128 See also read. Function: reveal (expr, depth) Replaces parts of expr at the specified integer depth with descriptive summaries. • Sums and differences are replaced by sum(n) where n is the number of operands of the sum. • Products are replaced by product(n) where n is the number of operands of the product. • Exponentials are replaced by expt. • Quotients are replaced by quotient. • Unary negation is replaced by negterm. When depth is greater than or equal to the maximum depth of expr, reveal (expr, depth) returns expr unmodified. reveal evaluates its arguments. reveal returns the summarized expression. Example: (%i1) e: expand ((a - b)^2)/expand ((exp(a) + exp(b))^2); 2 2 b - 2 a b + a (%o1) ------------------------- b + a 2 b 2 a 2 %e + %e + %e (%i2) reveal (e, 1); (%o2) quotient (%i3) reveal (e, 2); sum(3) (%o3) ------ sum(3) (%i4) reveal (e, 3); expt + negterm + expt (%o4) ------------------------ product(2) + expt + expt (%i5) reveal (e, 4); 2 2 b - product(3) + a (%o5) ------------------------------------ product(2) product(2) 2 expt + %e + %e (%i6) reveal (e, 5); 2 2 b - 2 a b + a (%o6) -------------------------- sum(2) 2 b 2 a 2 %e + %e + %e (%i7) reveal (e, 6); 2 2 b - 2 a b + a (%o7) ------------------------- b + a 2 b 2 a 2 %e + %e + %e Option variable: rmxchar Default value: ] rmxchar is the character drawn on the right-hand side of a matrix. See also lmxchar. Function: save (filename, name_1, name_2, name_3, ...) Function: save (filename, values, functions, labels, ...) Function: save (filename, [m, n]) Function: save (filename, name_1=expr_1, ...) Function: save (filename, all) Stores the current values of name_1, name_2, name_3, ..., in filename. The arguments are the names of variables, functions, or other objects. If a name has no value or function associated with it, it is ignored. save returns filename. save stores data in the form of Lisp expressions. The data stored by save may be recovered by load (filename). The global flag file_output_append governs whether save appends or truncates the output file. When file_output_append is true, save appends to the output file. Otherwise, save truncates the output file. In either case, save creates the file if it does not yet exist. The special form save (filename, values, functions, labels, ...) stores the items named by values, functions, labels, etc. The names may be any specified by the variable infolists. values comprises all user-defined variables. The special form save (filename, [m, n]) stores the values of input and output labels m through n. Note that m and n must be literal integers or double-quoted symbols. Input and output labels may also be stored one by one, e.g., save ("foo.1", %i42, %o42). save (filename, labels) stores all input and output labels. When the stored labels are recovered, they clobber existing labels. The special form save (filename, name_1=expr_1, name_2=expr_2, ...) stores the values of expr_1, expr_2, ..., with names name_1, name_2, .... It is useful to apply this form to input and output labels, e.g., save ("foo.1", aa=%o88). The right-hand side of the equality in this form may be any expression, which is evaluated. This form does not introduce the new names into the current Maxima environment, but only stores them in filename. These special forms and the general form of save may be mixed at will. For example, save (filename, aa, bb, cc=42, functions, [11, 17]). The special form save (filename, all) stores the current state of Maxima. This includes all user-defined variables, functions, arrays, etc., as well as some automatically defined items. The saved items include system variables, such as file_search_maxima or showtime, if they have been assigned new values by the user; see myoptions. save quotes its arguments. filename must be a string, not a string variable. The first and last labels to save, if specified, must be integers. The double quote operator evaluates a string variable to its string value, e.g., s: "foo.1"$ save (''s, all)$, and integer variables to their integer values, e.g., m: 5$ n: 12$save ("foo.1", [''m, ''n])$.
Option variable: savedef
Default value: true
When savedef is true, the Maxima version of a user function is preserved when the function is translated. This permits the definition to be displayed by dispfun and allows the function to be edited.
When savedef is false, the names of translated functions are removed from the functions list.
Function: show (expr)
Displays expr with the indexed objects in it shown having covariant indices as subscripts, contravariant indices as superscripts. The derivative indices are displayed as subscripts, separated from the covariant indices by a comma.
Function: showratvars (expr)
Returns a list of the canonical rational expression (CRE) variables in expression expr.
Option variable: stardisp
Default value: false
When stardisp is true, multiplication is displayed with an asterisk * between operands.
Function: string (expr)
Converts expr to Maxima's linear notation just as if it had been typed in.
The return value of string is a string, and thus it cannot be used in a computation.
Lisp variable: stringdisp
Default value: false
When ?stringdisp is true, strings are displayed enclosed in double quote marks. Otherwise, quote marks are not displayed.
?stringdisp is always true when displaying a function definition.
?stringdisp is a Lisp variable, so it must be written with a leading question mark ?.
Examples:
(%i1) ?stringdisp: false$(%i2) "This is an example string."; (%o2) This is an example string. (%i3) foo () := print ("This is a string in a function definition."); (%o3) foo() := print("This is a string in a function definition.") (%i4) ?stringdisp: true$ (%i5) "This is an example string."; (%o5) "This is an example string."
Function: stringout (filename, expr_1, expr_2, expr_3, ...)
Function: stringout (filename, [m, n])
Function: stringout (filename, input)
Function: stringout (filename, functions)
Function: stringout (filename, values)
stringout writes expressions to a file in the same form the expressions would be typed for input. The file can then be used as input for the batch or demo commands, and it may be edited for any purpose. stringout can be executed while writefile is in progress.
The global flag file_output_append governs whether stringout appends or truncates the output file. When file_output_append is true, stringout appends to the output file. Otherwise, stringout truncates the output file. In either case, stringout creates the file if it does not yet exist.
The general form of stringout writes the values of one or more expressions to the output file. Note that if an expression is a variable, only the value of the variable is written and not the name of the variable. As a useful special case, the expressions may be input labels (%i1, %i2, %i3, ...) or output labels (%o1, %o2, %o3, ...).
If grind is true, stringout formats the output using the grind format. Otherwise the string format is used. See grind and string.
The special form stringout (filename, [m, n]) writes the values of input labels m through n, inclusive.
The special form stringout (filename, input) writes all input labels to the file.
The special form stringout (filename, functions) writes all user-defined functions (named by the global list functions) to the file.
The special form stringout (filename, values) writes all user-assigned variables (named by the global list values) to the file. Each variable is printed as an assignment statement, with the name of the variable, a colon, and its value. Note that the general form of stringout does not print variables as assignment statements.
Function: tex (expr)
Function: tex (label)
Function: tex (expr, filename)
Function: tex (label, filename)
Prints a representation of an expression suitable for the TeX document preparation system. The result is a fragment of a document, which can be copied into a larger document but not processed by itself.
tex (expr) prints a TeX representation of expr on the console.
tex (label) prints a TeX representation of the expression named by label and assigns it an equation label (to be displayed to the left of the expression). The TeX equation label is the same as the Maxima label.
tex (expr, filename) appends a TeX representation of expr to the file filename. tex quotes the filename argument; quote-quote '' forces evaluation of the argument.
tex (label, filename) appends a TeX representation of the expression named by label, with an equation label, to the file filename. tex quotes the filename argument; quote-quote '' forces evaluation of the argument.
tex evaluates its argument after testing it to see if it is a label. Quote-quote '' forces evaluation of the argument, thereby defeating the test and preventing the label.
Examples:
(%i1) integrate (1/(1+x^3), x); 2 x - 1 2 atan(-------) log(x - x + 1) sqrt(3) log(x + 1) (%o1) - --------------- + ------------- + ---------- 6 sqrt(3) 3 (%i2) tex (%o1); $$-{{\log \left(x^2-x+1\right)}\over{6}}+{{\arctan \left({{2\,x-1 }\over{\sqrt{3}}}\right)}\over{\sqrt{3}}}+{{\log \left(x+1\right) }\over{3}}\leqno{\tt (\%o1)}$$ (%o2) (\%o1) (%i3) tex (integrate (sin(x), x)); $$-\cos x$$ (%o3) false (%i4) tex (%o1, "foo.tex"); (%o4) (\%o1)
Function: texput (a, s)
Function: texput (a, s, operator_type)
Function: texput (a, [s_1, s_2], matchfix)
Function: texput (a, [s_1, s_2, s_3], matchfix)
Set the TeX output for the atom a, which can be a symbol or the name of an operator.
texput (a, s) causes the tex function to interpolate the string s into the TeX output in place of a.
texput (a, s, operator_type), where operator_type is prefix, infix, or postfix causes the tex function to interpolate s into the TeX output in place of a, and to place the interpolated text in the appropriate position.
texput (a, [s_1, s_2], matchfix) causes the tex function to interpolate s_1 and s_2 into the TeX output on either side of the arguments of a. The arguments (if more than one) are separated by commas.
texput (a, [s_1, s_2, s_3], matchfix) causes the tex function to interpolate s_1 and s_2 into the TeX output on either side of the arguments of a, with s_3 separating the arguments.
Examples:
(%i1) texput (me,"\\mu_e"); (%o1) \mu_e (%i2) tex (me); $$\mu_e$$ (%o2) false (%i3) texput (lcm, "\\mathrm{lcm}"); (%o3) \mathrm{lcm} (%i4) tex (lcm (a, b)); $$\mathrm{lcm}\left(a , b\right)$$ (%o4) false (%i5) prefix ("grad"); (%o5) grad (%i6) texput ("grad", " \\nabla ", prefix); (%o6) 180 (%i7) tex (grad f); $$\nabla f$$ (%o7) false (%i8) infix ("~"); (%o8) ~ (%i9) texput ("~", " \\times ", infix); (%o9) 180 (%i10) tex (a ~ b); $$a \times b$$ (%o10) false (%i11) postfix ("@"); (%o11) @ (%i12) texput ("@", "!!", postfix); (%o12) 160 (%i13) tex (x @); $$x!!$$ (%o13) false (%i14) matchfix ("<<", ">>"); (%o14) << (%i15) texput ("<<", [" \\langle ", " \\rangle "], matchfix); (%o15) \langle ( \rangle , false) (%i16) tex (<>); $$\langle a \rangle$$ (%o16) false (%i17) tex (<>); $$\langle a , b \rangle$$ (%o17) false (%i18) texput ("<<", [" \\langle ", " \\rangle ", " \\, | \\,"], matchfix); (%o18) \langle ( \rangle , \, | \,) (%i19) tex (<>); $$\langle a \rangle$$ (%o19) false (%i20) tex (<>); $$\langle a \, | \,b \rangle$$ (%o20) false
Function: system (command)
Executes command as a separate process. The command is passed to the default shell for execution. system is not supported by all operating systems, but generally exists in Unix and Unix-like environments.
Supposing _hist.out is a list of frequencies which you wish to plot as a bar graph using xgraph.
(%i1) (with_stdout("_hist.out", for i:1 thru length(hist) do ( print(i,hist[i]))), system("xgraph -bar -brw .7 -nl < _hist.out"));
In order to make the plot be done in the background (returning control to Maxima) and remove the temporary file after it is done do:
system("(xgraph -bar -brw .7 -nl < _hist.out; rm -f _hist.out)&")
Option variable: ttyoff
Default value: false
When ttyoff is true, output expressions are not displayed. Output expressions are still computed and assigned labels. See labels.
Text printed by built-in Maxima functions, such as error messages and the output of describe, is not affected by ttyoff.
Function: with_stdout (filename, expr_1, expr_2, expr_3, ...)
Opens filename and then evaluates expr_1, expr_2, expr_3, .... The values of the arguments are not stored in filename, but any printed output generated by evaluating the arguments (from print, display, disp, or grind, for example) goes to filename instead of the console.
The global flag file_output_append governs whether with_stdout appends or truncates the output file. When file_output_append is true, with_stdout appends to the output file. Otherwise, with_stdout truncates the output file. In either case, with_stdout creates the file if it does not yet exist.
with_stdout returns the value of its final argument.
(%i1) with_stdout ("tmp.out", for i:5 thru 10 do print (i, "! yields", i!))$(%i2) printfile ("tmp.out")$ 5 ! yields 120 6 ! yields 720 7 ! yields 5040 8 ! yields 40320 9 ! yields 362880 10 ! yields 3628800
Function: writefile (filename)
Begins writing a transcript of the Maxima session to filename. All interaction between the user and Maxima is then recorded in this file, just as it appears on the console.
As the transcript is printed in the console output format, it cannot be reloaded into Maxima. To make a file containing expressions which can be reloaded, see save and stringout. save stores expressions in Lisp form, while stringout stores expressions in Maxima form.
The effect of executing writefile when filename already exists depends on the underlying Lisp implementation; the transcript file may be clobbered, or the file may be appended. appendfile always appends to the transcript file.
It may be convenient to execute playback after writefile to save the display of previous interactions. As playback displays only the input and output variables (%i1, %o1, etc.), any output generated by a print statement in a function (as opposed to a return value) is not displayed by playback.
closefile closes the transcript file opened by writefile or appendfile.
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This document was generated on March, 19 2006 using texi2html 1.76. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7819266319274902, "perplexity": 9430.637612412806}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296945376.29/warc/CC-MAIN-20230325222822-20230326012822-00021.warc.gz"} |
https://www.esaral.com/q/find-three-different-irrational-numbers-between-the-rational-numbers-88915 | # Find three different irrational numbers between the rational numbers
Question:
Find three different irrational numbers between the rational numbers $\frac{5}{7}$ and $\frac{9}{11}$.
Solution:
Let $x=\frac{5}{7}=0 . \overline{714285}$ and $y=\frac{9}{11}=0 . \overline{81}$
Here we observe that in the first decimal x has digit 7 and y has 8. So x < y. In the second decimal place x has digit 1. So, if we considering irrational numbers
$a=0.72072007200072 \ldots$
$b=0.73073007300073 \ldots$
$c=0.74074007400074 \ldots$
We find that
\$x
Hence are required irrational numbers. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5898391008377075, "perplexity": 757.3964131865561}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296949355.52/warc/CC-MAIN-20230330163823-20230330193823-00167.warc.gz"} |
http://mathhelpforum.com/algebra/166230-algebra-question-print.html | # Algebra question
• Dec 14th 2010, 10:39 AM
Jools
Algebra question
Hey all. The root of my problem is actually from a chemistry question I'm doing, but for some reason I can't wrap my head around the algebraic solution to a formula need to solve the question. It's fairly simple, but for some reason I'm stuck. It gives the answer as x = 0.18 which works when you plug it in, but I can't get to it. (Please ignore the spacing above and below the division sign as it won't recognize my spaces for some reason)
(1.0 - x)
-------------------- = 1.0
(0.50 + x) (1.0 + x)
Here's what I've done:
(1.0 - x)
------------------- = 1.0
(.5 + 1.5x + x^2)
(.5 + 1.5x + x^2) = (1.0 - x)
.5x + x^2 = .5
Therefore:
.5 = x^2 + .5x
I tried the quadratic formula but it didn't give me the right answer. Can anybody help? Thanks.
• Dec 14th 2010, 10:45 AM
mr fantastic
Quote:
Originally Posted by Jools
Hey all. The root of my problem is actually from a chemistry question I'm doing, but for some reason I can't wrap my head around the algebraic solution to a formula need to solve the question. It's fairly simple, but for some reason I'm stuck. It gives the answer as x = 0.18 which works when you plug it in, but I can't get to it. (Please ignore the spacing above and below the division sign as it won't recognize my spaces for some reason)
(1.0 - x)
-------------------- = 1.0
(0.50 + x) (1.0 + x)
Here's what I've done:
(1.0 - x)
------------------- = 1.0
(.5 + 1.5x + x^2)
(.5 + 1.5x + x^2) = (1.0 - x)
.5x + x^2 = .5 Mr F says: This does NOT follow from the previous line. You are meant to ADD x to both sides .... By the way, thankyou for posting your work. It makes it easy to diagnose your trouble.
Therefore:
.5 = x^2 + .5x
I tried the quadratic formula but it didn't give me the right answer. Can anybody help? Thanks.
And once you have fixed your mistake, I'm sure you know that you must re-arrange the equation into the form quadratic = 0 before using the quadratic formula.
• Dec 14th 2010, 10:46 AM
e^(i*pi)
Quote:
Originally Posted by Jools
(.5 + 1.5x + x^2) = (1.0 - x)
.5x + x^2 = .5
Your error is between these two lines. For whatever reasons you've subtracted when moving the -x from the right to the left when you should have added it.
EDIT: Mr F is right, far easier to figure out when work has been posted. Just out of interest what topic is this in chem?
• Dec 15th 2010, 06:07 AM
Jools
Thanks for your reply! In looking at it again I did make an error there, but on my paper I did it the right way, and still didn't get the answer from the book. Starting from where I made the error above:
x^2 + 2.5x - .5 = 0
a = 1 b = 2 c = -.5
Using the quadratic formula I come up with:
-2.5 +/- 1.44 which is either - 1.06 or - 3.94
Sorry about the confusion. And thanks again for the help.
P.S. The chemistry topic I am working on is chemical equilibrium. This formula is for finding the concentrations of reactants when volume changes.
• Dec 15th 2010, 08:04 AM
HallsofIvy
Then you are using the quadratic formula incorrectly.
$\frac{-b\pm\sqrt{b^2- 4ac}}{2a}$
The first part, $\frac{-b}{2a}$ is $\frac{-2}{2}= -1$, not "-2.5"
The discriminant is $\sqrt{b^2- 4ac}= \sqrt{2^2- 4(1)(-.5)}= \sqrt{4+ 2}= \sqrt{6}$ which is about 2.45, not "1.44".
• Dec 15th 2010, 10:47 AM
Jools
Ok got it. I wasn't including -b as part of the numerator, I was adding/subtracting it to the resolved fraction. Thans for all the help! | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 4, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8059912919998169, "perplexity": 604.531928606069}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-34/segments/1502886103891.56/warc/CC-MAIN-20170817170613-20170817190613-00539.warc.gz"} |
http://blog.oureducation.in/sample-paper-fluid-mechanics/ | ## SAMPLE PAPER – FLUID MECHANICS
Mar 26 2013 • Engineering Sample Papers • 2927 Views • No Comments on SAMPLE PAPER – FLUID MECHANICS
B.Tech (4th semester) FLUID MECHANICS
TIME : 3 hrs Max. Marks : 100
Note: Here are given 8 questions carrying 20 marks each for Fluid Mechanics. Attempt any five of them taking one from each unit and two questions from one unit.
UNIT – I
Q. 1 Derive Bernoulli’s theorem for a steady flow of a fluid from a pipe with height h1at one end to h2 at the other. State the assumptions involved in deriving this equation. Also write five applications for the Bernoulli’s equation in fluid mechanics. (20 marks)
Q. 2 i) Explain the condition for the stability and buoyancy for a body in a fluid. (10 marks)
ii) Define kinematic and dynamic viscosity. Also derive a suitable relationship between the two. (10 marks)
UNIT – II
Q. 3 i) Explain various types of fluids available in fluid mechanics. Also explain the relevant characteristic regarding these fluids. (10 marks)
ii) State and derive hydrostatic equation. (10 marks)
Q.4 i) Define control volume. Also derive an expression for the continuity equation. (10 marks)
ii) Derive momentum energy equation in case of a steady and uniform flow. (10 marks)
UNIT – III
Q.5 State and explain Rayleigh method and Buckingham-pie-theorem for the dimensional analysis with a suitable example. Also explain the advantages of using this theorem. Using this theorem, find the dimensions of viscosity, mass density and specific gravity. (20 marks)
Q. 6 i) Explain the following with neat sketches:
a) Simple manometer. (3 marks)
b) Single column manometer. (3 marks)
c) U tube manometer. (4 marks)
ii) Derive Euler’s equation of motion. Also obtain the Bernoulli’s theorem from the Euler’s equation. (10 marks)
UNIT – IV
Q. 7 i) Write a short note on boundary layer along a long thin flat plate and also explain their characteristics. (10 marks)
ii) Explain the Nusselt’s technique for obtaining the dimension of a parameter. (5 marks)
iii) Write down the significance of dimensionless numbers. Also explain relationships between various dimensionless numbers. (5 marks)
Q. 8 i) Explain Newtons law of Viscosity. (5 marks)
ii) What is a pitot tube. Also explain its various characteristics. (5 marks)
ii) Write down various means of obtaining the pressure measurement in case of a fluid having a uniform flow through a pipe. (10 marks) | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8949688673019409, "perplexity": 13047.428971827165}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-44/segments/1476988721405.66/warc/CC-MAIN-20161020183841-00230-ip-10-171-6-4.ec2.internal.warc.gz"} |
https://docs.eyesopen.com/toolkits/python/oechemtk/OEMathFunctions/OEGeom3DMatrixMultiply.html | # OEGeom3DMatrixMultiply¶
template<class T, class U>
void OEGeom3DMatrixMultiply(T *accumulator, const U *add)
template<class T, class U, class V>
void OEGeom3DMatrixMultiply(T *Product, const U *init, const V *add)
Performs $$3x3$$ matrix multiplication. The first form computes $$accumulator *= add$$, and the second form computes $$Product = init * add$$. All of the inputs are nine element $$3x3$$ matrices. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8518129587173462, "perplexity": 16287.982385558133}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-04/segments/1547583662690.13/warc/CC-MAIN-20190119054606-20190119080606-00560.warc.gz"} |
https://tohoku.pure.elsevier.com/ja/publications/solving-non-parametric-inverse-problem-in-continuous-markov-rando | # Solving non-parametric inverse problem in continuous Markov random field using loopy belief propagation
Muneki Yasuda, Shun Kataoka
## 抄録
In this paper, we address the inverse problem, or the statistical machine learning problem, in Markov random fields with a non-parametric pair-wise energy function with continuous variables. The inverse problem is formulated by maximum likelihood estimation. The exact treatment of maximum likelihood estimation is intractable because of two problems: (1) it includes the evaluation of the partition function and (2) it is formulated in the form of functional optimization. We avoid Problem (1) by using Bethe approximation. Bethe approximation is an approximation technique equivalent to the loopy belief propagation. Problem (2) can be solved by using orthonormal function expansion. Orthonormal function expansion can reduce a functional optimization problem to a function optimization problem. Our method can provide an analytic form of the solution of the inverse problem within the framework of Bethe approximation as a result of variational optimization.
本文言語 English 084806 journal of the physical society of japan 86 8 https://doi.org/10.7566/JPSJ.86.084806 Published - 2017 8 15
## ASJC Scopus subject areas
• 物理学および天文学（全般）
## フィンガープリント
「Solving non-parametric inverse problem in continuous Markov random field using loopy belief propagation」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9061022996902466, "perplexity": 780.8982010439754}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320304760.30/warc/CC-MAIN-20220125035839-20220125065839-00351.warc.gz"} |
https://www.arxiv-vanity.com/papers/1611.06561/ | Latest results from lattice N=4 super Yang–Mills
Institute for Theoretical Physics, University of Bern, 3012 Bern, Switzerland
E-mail:
Simon Catterall
Department of Physics, Syracuse University, Syracuse, New York 13244, United States
E-mail:
Poul H. Damgaard
Niels Bohr International Academy and Discovery Center, Niels Bohr Institute,
University of Copenhagen, 2100 Copenhagen, Denmark
E-mail:
Joel Giedt
Department of Physics, Applied Physics and Astronomy,
Rensselaer Polytechnic Institute, Troy, New York 12065, United States
E-mail:
Abstract:
We present some of the latest results from our numerical investigations of supersymmetric Yang–Mills theory formulated on a space-time lattice. Based on a construction that exactly preserves a single supersymmetry at non-zero lattice spacing, we recently developed an improved lattice action that is now being employed in large-scale calculations. Here we update our studies of the static potential using this new action, also applying tree-level lattice perturbation theory to improve the analysis of the potential itself. Considering relatively weak couplings, we obtain results for the Coulomb coefficient that are consistent with continuum perturbation theory.
Non-perturbative investigations of supersymmetric Yang–Mills (SYM) formulated on a space-time lattice have advanced rapidly in recent years. In addition to playing important roles in holographic approaches to quantum gravity, investigations of the structure of scattering amplitudes, and the conformal bootstrap program, SYM is also the only known four-dimensional theory for which a lattice regularization can exactly preserve a closed subalgebra of the supersymmetries at non-zero lattice spacing [1, 2, 3, 4, 5]. Based on this lattice construction we have been pursuing large-scale numerical investigations of SYM that can in principle access non-perturbative couplings for arbitrary numbers of colors . Here we discuss a selection of our latest results from this work in progress.
Last year we introduced a procedure to regulate flat directions in numerical computations by modifying the moduli equations in a way that preserves the single exact supersymmetry at non-zero lattice spacing [6, 7, 8]. This procedure produces a lattice action that exhibits effective improvement, with significantly reduced discretization artifacts that vanish much more rapidly upon approaching the continuum limit. We have implemented this improved action in our parallel software for lattice SYM [9], and are now employing it in the large-scale numerical computations discussed in this proceedings. We make our software publicly available to encourage independent investigations and the development of a lattice SYM community.
In this proceedings, after briefly reviewing the improved action we revisit our lattice investigations of the static potential [10, 11]. In addition to the new lattice action, we also improve the static potential analysis itself by applying tree-level lattice perturbation theory. We observe a coulombic potential and our preliminary results for the Coulomb coefficient are consistent with continuum perturbative predictions. A separate contribution to these proceedings [12] discusses our efforts to investigate S duality on the Coulomb branch of SYM where some of the adjoint scalar fields acquire non-zero vacuum expectation values leading to spontaneous symmetry breaking. These efforts involve measuring the masses of the elementary W boson and the corresponding dual topological ’t Hooft–Polyakov monopole. Ref. [12] also provides an update on our ongoing investigations of the Konishi operator scaling dimension.
Improved lattice action for N=4 Sym
Our lattice formulation of SYM is based on the Marcus (or Geometric-Langlands) topological twist of the continuum theory [13, 14]. This produces a gauge theory with a five-component complexified gauge field in four space-time dimensions. We discretize the theory on the lattice, exactly preserving the closed subalgebra involving the single twisted-scalar supercharge . The improved lattice action that we use is [6]
S =N2λlat∑n{Tr[Q(χab(n)D(+)aUb(n)+η(n){¯¯¯¯D(−)aUa(n)+GO(n)IN}−12η(n)d(n))] −14Tr[ϵabcde χde(n+ˆμa+ˆμb+ˆμc)¯¯¯¯D(+)cχab(n)]+μ2∑a(1NTr[Ua(n)¯¯¯¯Ua(n)]−1)2},
where the operator in the first line is and is the oriented plaquette built from the complexified gauge links in the plane. Repeated indices are summed and the forward/backward finite-difference operators both reduce to the usual covariant derivatives in the continuum limit [3, 4]. All indices run from 1 through 5, corresponding to the five symmetric basis vectors of the four-dimensional lattice [2, 11].
When this action has the same form as the twisted continuum theory [13, 14]. These two tunable couplings are introduced to stabilize numerical calculations by regulating flat directions and exact zero modes. The scalar potential with coupling lifts flat directions in the SU() sector, while the plaquette determinant with coupling does so in the U(1) sector. Although non-zero softly breaks the supersymmetry, the plaquette determinant deformation is exact. This -exact deformation results from the general procedure introduced in Ref. [6], which imposes the Ward identity by modifying the equations of motion for the auxiliary field,
d(n)=¯¯¯¯D(−)aUa(n)⟶d(n)=¯¯¯¯D(−)aUa(n)+GO(n)IN. (1)
With this Ward identity gives after averaging over the lattice volume, while is constrained by the scalar potential. Thanks to the reduced soft supersymmetry breaking enabled by this procedure, Ward identity violations vanish in the continuum limit [8]. This is consistent with the improvement expected since and the other lattice symmetries forbid all dimension-5 operators [6].
With the moduli space of the lattice theory survives to all orders of lattice perturbation theory [15]. If nonperturbative effects such as instantons also preserve the moduli space, then the most general long-distance effective action contains only the terms in the improved action above [11, 16]. In addition, all but one of the coefficients on the terms in can be absorbed by rescaling the fermions and the auxiliary field, leaving only a single coupling that may need to be tuned to recover the full symmetries of SYM in the continuum limit.
Tree-level improvement for the lattice N=4 SYM static potential
We extract the static potential from the exponential temporal decay of rectangular Wilson loops . To easily analyze all possible spatial separations we gauge fix to Coulomb gauge and compute , where is the product of complexified temporal links at spatial location , extending from timeslice to timeslice .
The static potential analysis can be improved by refining the scalar distance associated with the spatial three-vector . This is a long-established idea in lattice gauge theory, dating back at least to Ref. [17]. Previously we identified the scalar distance as the euclidean norm of , where each is a basis vector of the lattice. Because these basis vectors are not orthogonal, is a four-vector in physical space-time even though is a three-vector displacement on a fixed timeslice of the lattice.
To obtain tree-level improvement we instead extract the scalar distance from the Fourier transform of the bosonic propagator computed at tree level in lattice perturbation theory. Then to this order in lattice perturbation theory. Using the tree-level lattice propagator computed in Ref. [15], we have
In this expression is the same four-vector discussed above while and the dual basis vectors are defined by . The last identity allows us to replace and , more directly relating to the three-vector displacement .
On a finite lattice, the continuous integral in Eq. 2 would reduce to a discrete sum over integer . Since we have not yet computed the zero-mode () contribution to the discrete sum, here we determine by numerically evaluating the continuous integral that corresponds to the infinite-volume limit. Ref. [17] argues that infinite-volume can safely be used in finite-volume lattice calculations, without affecting either the Coulomb coefficient or the string tension. In agreement with this argument, we checked that both approaches give us similar results even though we currently omit the zero-mode contribution from the finite-volume computation.
We experimented with three integrators to numerically evaluate the four-dimensional integral in Eq. 2, obtaining consistent results but significantly different performance. For our problem the most efficient integrator we were able to find was the Divonne algorithm implemented in the Cuba library [18]. This is a stratified sampling algorithm based on CERNLIB routine D151 [19]. Especially for large Divonne’s evaluation of Eq. 2 converged several orders of magnitude more rapidly than two versions of the vegas algorithm [20] that we tested. These two versions of vegas both provide some improvements over the original algorithm, and are implemented in Cuba and at http://github.com/gplepage/vegas.
Latest results for the static potential
In Fig. 1 we demonstrate the effects of tree-level improvement for lattice SYM computations of the static potential. All four plots in this figure consider lattices generated using the improved action at ’t Hooft coupling . The top row of plots analyze with the scalar distance defined by the naive euclidean norm of . In the top-left plot we show the potential itself for gauge groups U() with , 3 and 4, including fits to the Coulomb form . It is possible to see that the first points at are consistently below the fit curves, while the next points at are well above them. This scatter of the points around the fit is isolated in the top-right plot where we show .
It is precisely this scatter at short distances that tree-level improvement ameliorates, as shown in the bottom row of plots. These results come from the same gauge configurations and measurements as those in the top row, with the only change in the analysis being the use of obtained from Eq. 2 via the Divonne integrator in Cuba. There is not a one-to-one correspondence between the points in the two rows of plots. Several that produce the same euclidean norm (and are therefore combined in our original analyses) lead to distinct . At the same time, the finite-volume effects also change. We drop any displacements that extend at least halfway across the spatial volume of the lattice. When working with euclidean norms for , this imposes , whereas .
In Fig. 2 we collect preliminary results from tree-level improved static potential analyses employing our new ensembles of gauge configurations generated using the improved action. On lattices we consider three U() gauge groups with , 3 and 4, while to explore finite-volume effects we also carry out and calculations for . (Because the larger volumes also help to control discretization artifacts at stronger couplings, so far we have only generated lattices at the strongest included in this analysis.) A notable finite-volume effect that we observe is a small negative value for the string tension when we fit the static potential to the confining form . We can see in Fig. 1 that such a negative string tension would improve the fit for distances near the finite-volume cutoff. As increases we gain data at larger distances, which more effectively constrain . In the right plot of Fig. 2 we see that the string tension moves toward zero as increases, confirming that the static potential is coulombic at all couplings we consider.
We therefore fit the static potential to the Coulomb form to obtain the results for the Coulomb coefficient in the left plot of Fig. 2. For the same gauge groups and lattice volumes discussed above our results are consistent with the next-to-next-to-leading-order (NNLO) perturbative prediction from Refs. [21, 22, 23]. The agreement with perturbation theory tends to improve as and increase, especially at the strongest ’t Hooft coupling where the larger volume helps control discretization artifacts.
Next steps for lattice N=4 Sym
We are near to finalizing and publishing our tree-level improved analyses of the lattice SYM static potential based on the improved lattice action introduced last year and summarized above. In addition we are making progress analyzing the anomalous dimension of the Konishi operator, developing a variational method to disentangle the Konishi and supergravity () operators as described in Ref. [12]. We continue to investigate the possible sign problem of the lattice theory, as well as the restoration of the other supersymmetries and in the continuum limit. Finally, Ref. [12] also presents a new project to study S duality on the Coulomb branch of the theory, by measuring the masses of the W boson and the corresponding dual topological ’t Hooft–Polyakov monopole. Ideally this Coulomb branch investigation will allow non-perturbative lattice tests of S duality even at ’t Hooft couplings relatively far from the self-dual point .
Acknowledgments: We thank Tom DeGrand, Julius Kuti and Rainer Sommer for helpful discussions of perturbative improvement for the static potential, and Rudi Rahn for advice on numerical integration. This work was supported by the U.S. Department of Energy (DOE), Office of Science, Office of High Energy Physics, under Award Numbers DE-SC0009998 (DS, SC) and DE-SC0013496 (JG). Numerical calculations were carried out on the HEP-TH cluster at the University of Colorado, the DOE-funded USQCD facilities at Fermilab, and the Comet cluster at the San Diego Computing Center through the Extreme Science and Engineering Discovery Environment (XSEDE) supported by U.S. National Science Foundation grant number ACI-1053575. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.897934079170227, "perplexity": 888.2108939571198}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-49/segments/1637964358323.91/warc/CC-MAIN-20211127223710-20211128013710-00503.warc.gz"} |
https://chemistry.stackexchange.com/questions/145031/can-you-separate-co2-into-carbon-and-oxygen-using-pyrolysis | # Can you separate CO2 into carbon and oxygen using pyrolysis? [duplicate]
I recently read about a pyrolysis process that separates methane into Carbon and Hydrogen. The basic technology/process is you have a vertical column of super-heated liquid metal and you inject methane into the bottom of the column. The methane breaks down into hydrogen and solid carbon. Are there any similar processes that separate CO2 into solid carbon and oxygen using liquid metals and/or salts etc.?
• chemistry.stackexchange.com/questions/915/… – Mithoron Jan 15 at 2:05
• Not energetically feasible at all. – M. Farooq Jan 15 at 5:06
• The current modeling of future power system operations suggests there will be a large amount of excess generation which is "spilled" and/or dumped because there is no practical use for the electricity. This is called over-build and spill. It's a new/old strategy in power system operations. There will be many cases where we can dump this power into a thermal reservoir of some sort and then gradually draw off the reservoir to accomplish some task. It could be drying wood or making powdered milk or possibly pyrolysis. I'm asking if there's a known pyrolysis process that accomplishes this. – Lee Jan 15 at 7:35
• By this I mean a pyrolysis process that breaks up CO2 into carbon and oxygen using a liquid metal bath and/or a salt and or some other thermal + catalyst driven process. – Lee Jan 15 at 7:36
• The answer is No ! Unfortunately ! $\ce{CO2}$ cannot be transformed into $\ce{C + O2}$ using liquid metals or salts. If it would have been feasible, somebody would have already done it somewhere. – Maurice Jan 15 at 9:57
Standard enthalpy of formation of carbon dioxide is -393.5 kJ/mol. Standard enthalpy of formation of both oxygen and graphite is 0 J/mol. Standard entropy of carbon dioxide is 213.8 J/mol-K (NIST). Standard entropy of oxygen is 205 J/mol-K (Chem LibreTexts). Standard entropy of graphite is 5.69 J/mol-K (ChemLibreTexts).
Everything below is a lot of fairly inexact approximations/assumptions because I didn't want to use a better model or search literature for empirical adjustments and/or constants.
Assuming constant T,P (which I doubt would be true under reactor conditions) G = H - TS. Approximating $$\Delta H, \Delta S$$ as constant with T, $$\Delta G = (0 - (-393500)) - (T \cdot (5.69 + 205 - 213.8)) = 393500 + T \cdot (3.11)$$. Then $$\Delta G < 0$$ regardless of temperature. Catalysts also do not affect thermodynamics, so this process can never occur spontaneously. Increasing pressure of the reaction chamber would not help appreciably either, as the reaction has 1 mol gas on each side. While assuming $$\Delta H, \Delta S$$ are constant with T is quite incorrect as conditions become more extreme, the approximation should suffice to show that the reaction does not occur easily. Additionally, even if one were to account for the perturbations in $$\Delta H, \Delta S$$ with T and P, these conditions would be expensive to maintain in a reactor. (Note that this analysis does not even account for the activation energy/kinetics problem! I did not look up the activation energy of the problem, but it is entirely possible that the extreme conditions would still not allow the process to occur at a reasonable rate.)
As a result, this reaction is (probably) practically only driven forward by direct energy input (aka a coupled reaction/external energy). This often, if not always, involves some energy input, such as light or a coupled chemical reaction, that directly impacts the electron states of the participant compounds. These changes in electron states change the identity/properties and stability of compounds, and, when applied effectively, they can help drive the reaction forward. However, relevant changes to electron states using heat not only often involve very high temperatures, but the effect of heat on electron states is also a highly statistical process. Thus, it may be relatively inefficient. Thus, pyrolysis, while it may be theoretically possible, would be incredibly impractical at achieving separation of carbon dioxide. (Also, to compare to your methane example, methane combusts readily, carbon dioxide does not. Methane has a standard enthalpy of formation of -74.87 kJ/mol.)
Finally, if you still need more reasons to look at a different way to drive this reaction, I have not mentioned: energy/cost to continuously scrape/collect the produced carbon, purify/collect/pressurize an inlet carbon dioxide stream, (if you actually want to run the reaction, you'll probably want) catalytic surfaces to encourage carbon deposition, possible packed/fluidized bed catalysts, heat exchangers, and much, much more.
ELI5: Methane combusts/reacts readily and is an "unstable" compound. Carbon dioxide is very stable and does not react easily. Higher temperatures can make some reactions that do not happen at a lower temperatures occur, but this particular reaction receives no such benefit. Heat and catalysis can also drive forward the speed of a reaction, but the reaction has to be able to occur first. Pyrolysis, as you described it, involves catalysts and heat. As a result, pyrolysis cannot be used to separate carbon dioxide into carbon and oxygen.
tldr: Excepting conditions extreme enough to perturb $$\Delta H_{rxn}, \Delta S_{rxn}$$, conditions of constant T,P never favor breakdown of carbon dioxide into elemental carbon and diatomic oxygen. Pyrolysis cannot drive this reaction.
• Thanks for all of that. How about this? What if you had two stages of reactions. Stage 1: Fe3O2 is heated to 1500C driving off oxygen. The resulting FeO is moved to CO2 chamber where it absorbs oxygen from the CO2. Result is CO and cooled Fe3O2. – Lee Jan 17 at 2:36
• Stage 2: Pyrolyze the carbon monoxide. I realize this may sound like a silly waste of fuel but I'm only asking if it's technically possible? This may sound strange but there's a high probability we'll "spill" upwards of 25 to 40% of our total electricity production in the future. This won't really start to happen for 20 years but this is where we are headed. Dumping this production into a thermal reservoir and then pulling off the thermal energy could be a good way to utilize some of this spill. – Lee Jan 17 at 2:45
• Aha.... Here is the sort of thing I was looking for. thechemicalengineer.com/news/turning-co2-into-carbon-black You make methane first by combining CO2 and hydrogen. Pyrolyze the methane into carbon and hydrogen. Repeat cycle. – Lee Jan 17 at 3:19 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 6, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5771543979644775, "perplexity": 1467.415397491359}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046154459.22/warc/CC-MAIN-20210803124251-20210803154251-00589.warc.gz"} |
https://embed.planetcalc.com/577/ | Sine wave calculator
Construction of a sine wave with the user's parameters
This calculator builds a parametric sinusoid in the range from 0 to $2\pi$
Why parametric? Because the graph is represented by the following formula
$y(x)=sin(kx+a)$, and the coefficients k and a can be set by the user.
Some words about the form in which the user can set the coefficients – there are three possible forms:
The number put in the box is interpreted as radians, for example, 2 radians
2. Degrees
The number put in the box is interpreted as degrees, for example, 60 degrees
The number put in the box is interpreted as a factor in front of the number $\pi$, for example, 2$\pi$ radian
By default, k = 1, a = 0, which gives us a classic graph $y(x)=sin(x)$
P.S. It is clear that when k is very large, the graph looks shitty, but what can you do – its a linear approximation after all!
Sine wave
Digits after the decimal point: 2
Sine wave
The file is very large. Browser slowdown may occur during loading and creation.
URL copied to clipboard
PLANETCALC, Sine wave calculator | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 5, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8405698537826538, "perplexity": 800.1422413951292}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-27/segments/1656103324665.17/warc/CC-MAIN-20220627012807-20220627042807-00260.warc.gz"} |
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## Found 39 Documents (Results 1–39)
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### A novel two-grid method for a fracture model. (English)Zbl 07443249
MSC: 76-XX 65-XX
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https://math.hecker.org/2014/03/08/linear-algebra-and-its-applications-exercise-3-1-11/ | Linear Algebra and Its Applications, Exercise 3.1.11
Exercise 3.1.11. Fredholm’s alternative to the fundamental theorem of linear algebra states that for any matrix $A$ and vector $b$ either
1) $Ax = b$
has a solution or
2) $A^Ty = 0, y^Tb \ne 0$
has a solution, but not both. Show that assuming both (1) and (2) have solutions leads to a contradiction.
Answer: Suppose that both (1) and (2) have solutions for any matrix $A$ and any vector $b$. In other words $Ax = b$ for some $x$ and $A^Ty = 0$ for some $y$, where $y^Tb \ne 0$.
Since $A^Ty = 0$ we also have $(A^Ty)^T = 0$. But $(A^Ty)^T = y^T(A^T)^T = y^TA$ so that we also have $y^TA = 0$. Multiplying both sides by $x$ we have $y^TAx = 0 \cdot x = 0$. But $Ax = b$ so the equation $y^TAx = 0$ reduces to $y^Tb = 0$ contrary to our original assumption that $y^Tb \ne 0$.
We have thus shown that either (1) can have a solution or (2) can have a solution but not both at the same time.
NOTE: This continues a series of posts containing worked out exercises from the (out of print) book Linear Algebra and Its Applications, Third Edition by Gilbert Strang.
If you find these posts useful I encourage you to also check out the more current Linear Algebra and Its Applications, Fourth Edition, Dr Strang’s introductory textbook Introduction to Linear Algebra, Fourth Edition and the accompanying free online course, and Dr Strang’s other books.
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Acoustic theory is the field relating to mathematical description of sound waves. It is derived from fluid dynamics. See acoustics for the engineering approach.
The propagation of sound waves in a fluid (such as water) can be modeled by an equation of motion (conservation of momentum) and an equation of continuity (conservation of mass). With some simplifications, in particular constant density, they can be given as follows:
\begin{align} \rho_0 \frac{\partial \mathbf{v}}{\partial t} + \nabla p & = 0 \qquad \text{(Momentum balance)} \\ \frac{\partial p}{\partial t} + \kappa~\nabla \cdot \mathbf{v} & = 0 \qquad \text{(Mass balance)} \end{align}
where $p(\mathbf{x}, t)$ is the acoustic pressure and $\mathbf{v}(\mathbf{x}, t)$ is the acoustic fluid velocity vector, $\mathbf{x}$ is the vector of spatial coordinates $x, y, z$, $t$ is the time, $\rho_0$ is the static mass density of the medium and $\kappa$ is the bulk modulus of the medium. The bulk modulus can be expressed in terms of the density and the speed of sound in the medium ($c_0$) as
$\kappa = \rho_0 c_0^2 ~.$
If the acoustic fluid velocity field is irrotational, $\nabla \times \mathbf{v}=\mathbf{0}$, then the acoustic wave equation is a combination of these two sets of balance equations and can be expressed as [1]
$\cfrac{\partial^2 \mathbf{v}}{\partial t^2} - c_0^2~\nabla^2\mathbf{v} = 0 \qquad \text{or} \qquad \cfrac{\partial^2 p}{\partial t^2} - c_0^2~\nabla^2 p = 0,$
where we have used the vector Laplacian, $\nabla^2 \mathbf{v} = \nabla(\nabla \cdot \mathbf{v}) - \nabla \times (\nabla \times \mathbf{v})$ . The acoustic wave equation (and the mass and momentum balance equations) are often expressed in terms of a scalar potential $\varphi$ where $\mathbf{v} = \nabla\varphi$. In that case the acoustic wave equation is written as
$\cfrac{\partial^2 \varphi}{\partial t^2} - c_0^2~\nabla^2 \varphi = 0$
and the momentum balance and mass balance are expressed as
$p + \rho_0~\cfrac{\partial\varphi}{\partial t} = 0 ~;~~ \rho + \cfrac{\rho_0}{c_0^2}~\cfrac{\partial\varphi}{\partial t} = 0 ~.$
## Derivation of the governing equations
The derivations of the above equations for waves in an acoustic medium are given below.
### Conservation of momentum
The equations for the conservation of linear momentum for a fluid medium are
$\rho \left(\frac{\partial \mathbf{v}}{\partial t} + \mathbf{v} \cdot \nabla \mathbf{v}\right) = -\nabla p + \nabla \cdot\boldsymbol{s} + \rho\mathbf{b}$
where $\mathbf{b}$ is the body force per unit mass, $p$ is the pressure, and $\boldsymbol{s}$ is the deviatoric stress. If $\boldsymbol{\sigma}$ is the Cauchy stress, then
$p := -\tfrac{1}{3}~\text{tr}(\boldsymbol{\sigma}) ~;~~ \boldsymbol{s} := \boldsymbol{\sigma} + p~\boldsymbol{\mathit{1}}$
where $\boldsymbol{\mathit{1}}$ is the rank-2 identity tensor.
We make several assumptions to derive the momentum balance equation for an acoustic medium. These assumptions and the resulting forms of the momentum equations are outlined below.
#### Assumption 1: Newtonian fluid
In acoustics, the fluid medium is assumed to be Newtonian. For a Newtonian fluid, the deviatoric stress tensor is related to the velocity by
$\boldsymbol{s} = \mu~\left[\nabla\mathbf{v} + (\nabla\mathbf{v})^T\right] + \lambda~(\nabla \cdot \mathbf{v})~\boldsymbol{\mathit{1}}$
where $\mu$ is the shear viscosity and $\lambda$ is the bulk viscosity.
Therefore, the divergence of $\boldsymbol{s}$ is given by
\begin{align} \nabla\cdot\boldsymbol{s} \equiv \cfrac{\partial s_{ij}}{\partial x_i} & = \mu \left[\cfrac{\partial}{\partial x_i}\left(\cfrac{\partial v_i}{\partial x_j}+\cfrac{\partial v_j}{\partial x_i}\right)\right] + \lambda~\left[\cfrac{\partial}{\partial x_i}\left(\cfrac{\partial v_k}{\partial x_k}\right)\right]\delta_{ij} \\ & = \mu~\cfrac{\partial^2 v_i}{\partial x_i \partial x_j} + \mu~\cfrac{\partial^2 v_j}{\partial x_i\partial x_i} + \lambda~\cfrac{\partial^2 v_k}{\partial x_k\partial x_j} \\ & = (\mu + \lambda)~\cfrac{\partial^2 v_i}{\partial x_i \partial x_j} + \mu~\cfrac{\partial^2 v_j}{\partial x_i^2} \\ & \equiv (\mu + \lambda)~\nabla(\nabla\cdot\mathbf{v}) + \mu~\nabla^2\mathbf{v} ~. \end{align}
Using the identity $\nabla^2\mathbf{v} = \nabla(\nabla\cdot\mathbf{v}) - \nabla\times\nabla\times\mathbf{v}$, we have
$\nabla\cdot\boldsymbol{s} = (2\mu + \lambda)~\nabla(\nabla\cdot\mathbf{v}) - \mu~\nabla\times\nabla\times\mathbf{v}~.$
The equations for the conservation of momentum may then be written as
$\rho \left(\frac{\partial \mathbf{v}}{\partial t} + \mathbf{v} \cdot \nabla \mathbf{v}\right) = -\nabla p + (2\mu + \lambda)~\nabla(\nabla\cdot\mathbf{v}) - \mu~\nabla\times\nabla\times\mathbf{v} + \rho\mathbf{b}$
#### Assumption 2: Irrotational flow
For most acoustics problems we assume that the flow is irrotational, that is, the vorticity is zero. In that case
$\nabla\times\mathbf{v} = 0$
and the momentum equation reduces to
$\rho \left(\frac{\partial \mathbf{v}}{\partial t} + \mathbf{v} \cdot \nabla \mathbf{v}\right) = -\nabla p + (2\mu + \lambda)~\nabla(\nabla\cdot\mathbf{v}) + \rho\mathbf{b}$
#### Assumption 3: No body forces
Another frequently made assumption is that effect of body forces on the fluid medium is negligible. The momentum equation then further simplifies to
$\rho \left(\frac{\partial \mathbf{v}}{\partial t} + \mathbf{v} \cdot \nabla \mathbf{v}\right) = -\nabla p + (2\mu + \lambda)~\nabla(\nabla\cdot\mathbf{v})$
#### Assumption 4: No viscous forces
Additionally, if we assume that there are no viscous forces in the medium (the bulk and shear viscosities are zero), the momentum equation takes the form
$\rho \left(\frac{\partial \mathbf{v}}{\partial t} + \mathbf{v} \cdot \nabla \mathbf{v}\right) = -\nabla p$
#### Assumption 5: Small disturbances
An important simplifying assumption for acoustic waves is that the amplitude of the disturbance of the field quantities is small. This assumption leads to the linear or small signal acoustic wave equation. Then we can express the variables as the sum of the (time averaged) mean field ($\langle\cdot\rangle$) that varies in space and a small fluctuating field ($\tilde{\cdot}$) that varies in space and time. That is
$p = \langle p\rangle + \tilde{p} ~;~~ \rho = \langle\rho\rangle + \tilde{\rho} ~;~~ \mathbf{v} = \langle\mathbf{v}\rangle + \tilde{\mathbf{v}}$
and
$\cfrac{\partial\langle p \rangle}{\partial t} = 0 ~;~~ \cfrac{\partial\langle \rho \rangle}{\partial t} = 0 ~;~~ \cfrac{\partial\langle \mathbf{v} \rangle}{\partial t} = \mathbf{0} ~.$
Then the momentum equation can be expressed as
$\left[\langle\rho\rangle+\tilde{\rho}\right] \left[\frac{\partial\tilde{\mathbf{v}}}{\partial t} + \left[\langle\mathbf{v}\rangle+\tilde{\mathbf{v}}\right] \cdot \nabla \left[\langle\mathbf{v}\rangle+\tilde{\mathbf{v}}\right]\right] = -\nabla \left[\langle p\rangle+\tilde{p}\right]$
Since the fluctuations are assumed to be small, products of the fluctuation terms can be neglected (to first order) and we have
\begin{align} \langle\rho\rangle~\frac{\partial\tilde{\mathbf{v}}}{\partial t} & + \left[\langle\rho\rangle+\tilde{\rho}\right]\left[\langle\mathbf{v}\rangle\cdot\nabla \langle\mathbf{v}\rangle\right]+ \langle\rho\rangle\left[\langle\mathbf{v}\rangle\cdot\nabla\tilde{\mathbf{v}} + \tilde{\mathbf{v}}\cdot\nabla\langle\mathbf{v}\rangle\right] \\ & = -\nabla \left[\langle p\rangle+\tilde{p}\right] \end{align}
#### Assumption 6: Homogeneous medium
Next we assume that the medium is homogeneous; in the sense that the time averaged variables $\langle p \rangle$ and $\langle \rho \rangle$ have zero gradients, i.e.,
$\nabla\langle p \rangle = 0 ~;~~ \nabla\langle \rho \rangle = 0 ~.$
The momentum equation then becomes
$\langle\rho\rangle~\frac{\partial\tilde{\mathbf{v}}}{\partial t} + \left[\langle\rho\rangle+\tilde{\rho}\right]\left[\langle\mathbf{v}\rangle\cdot\nabla \langle\mathbf{v}\rangle\right]+ \langle\rho\rangle\left[\langle\mathbf{v}\rangle\cdot\nabla\tilde{\mathbf{v}} + \tilde{\mathbf{v}}\cdot\nabla\langle\mathbf{v}\rangle\right] = -\nabla\tilde{p}$
#### Assumption 7: Medium at rest
At this stage we assume that the medium is at rest which implies that the mean velocity is zero, i.e. $\langle\mathbf{v}\rangle = 0$. Then the balance of momentum reduces to
$\langle\rho\rangle~\frac{\partial\tilde{\mathbf{v}}}{\partial t} = -\nabla\tilde{p}$
Dropping the tildes and using $\rho_0 := \langle\rho\rangle$, we get the commonly used form of the acoustic momentum equation
$\rho_0~\frac{\partial\mathbf{v}}{\partial t} + \nabla p = 0 ~.$
### Conservation of mass
The equation for the conservation of mass in a fluid volume (without any mass sources or sinks) is given by
$\frac{\partial \rho}{\partial t} + \nabla \cdot (\rho \mathbf{v}) = 0$
where $\rho(\mathbf{x},t)$ is the mass density of the fluid and $\mathbf{v}(\mathbf{x},t)$ is the fluid velocity.
The equation for the conservation of mass for an acoustic medium can also be derived in a manner similar to that used for the conservation of momentum.
#### Assumption 1: Small disturbances
From the assumption of small disturbances we have
$p = \langle p\rangle + \tilde{p} ~;~~ \rho = \langle\rho\rangle + \tilde{\rho} ~;~~ \mathbf{v} = \langle\mathbf{v}\rangle + \tilde{\mathbf{v}}$
and
$\cfrac{\partial\langle p \rangle}{\partial t} = 0 ~;~~ \cfrac{\partial\langle \rho \rangle}{\partial t} = 0 ~;~~ \cfrac{\partial\langle \mathbf{v} \rangle}{\partial t} = \mathbf{0} ~.$
Then the mass balance equation can be written as
$\frac{\partial\tilde{\rho}}{\partial t} + \left[\langle\rho\rangle+\tilde{\rho}\right]\nabla \cdot\left[\langle\mathbf{v}\rangle+\tilde{\mathbf{v}}\right] + \nabla\left[\langle\rho\rangle+\tilde{\rho}\right]\cdot \left[\langle\mathbf{v}\rangle+\tilde{\mathbf{v}}\right]= 0$
If we neglect higher than first order terms in the fluctuations, the mass balance equation becomes
$\frac{\partial\tilde{\rho}}{\partial t} + \left[\langle\rho\rangle+\tilde{\rho}\right]\nabla \cdot\langle\mathbf{v}\rangle+ \langle\rho\rangle\nabla\cdot\tilde{\mathbf{v}} + \nabla\left[\langle\rho\rangle+\tilde{\rho}\right]\cdot\langle\mathbf{v}\rangle+ \nabla\langle\rho\rangle\cdot\tilde{\mathbf{v}}= 0$
#### Assumption 2: Homogeneous medium
Next we assume that the medium is homogeneous, i.e.,
$\nabla\langle \rho \rangle = 0 ~.$
Then the mass balance equation takes the form
$\frac{\partial\tilde{\rho}}{\partial t} + \left[\langle\rho\rangle+\tilde{\rho}\right]\nabla \cdot\langle\mathbf{v}\rangle+ \langle\rho\rangle\nabla\cdot\tilde{\mathbf{v}} + \nabla\tilde{\rho}\cdot\langle\mathbf{v}\rangle = 0$
#### Assumption 3: Medium at rest
At this stage we assume that the medium is at rest, i.e., $\langle\mathbf{v}\rangle = 0$. Then the mass balance equation can be expressed as
$\frac{\partial\tilde{\rho}}{\partial t} + \langle\rho\rangle\nabla\cdot\tilde{\mathbf{v}} = 0$
#### Assumption 4: Ideal gas, adiabatic, reversible
In order to close the system of equations we need an equation of state for the pressure. To do that we assume that the medium is an ideal gas and all acoustic waves compress the medium in an adiabatic and reversible manner. The equation of state can then be expressed in the form of the differential equation:
$\cfrac{dp}{d\rho} = \cfrac{\gamma~p}{\rho} ~;~~ \gamma := \cfrac{c_p}{c_v} ~;~~ c^2 = \cfrac{\gamma~p}{\rho} ~.$
where $c_p$ is the specific heat at constant pressure, $c_v$ is the specific heat at constant volume, and $c$ is the wave speed. The value of $\gamma$ is 1.4 if the acoustic medium is air.
For small disturbances
$\cfrac{dp}{d\rho} \approx \cfrac{\tilde{p}}{\tilde{\rho}} ~;~~ \cfrac{p}{\rho} \approx \cfrac{\langle p \rangle}{\langle \rho \rangle} ~;~~ c^2 \approx c_0^2 = \cfrac{\gamma~\langle p\rangle}{\langle \rho \rangle} ~.$
where $c_0$ is the speed of sound in the medium.
Therefore,
$\cfrac{\tilde{p}}{\tilde{\rho}} = \gamma~\cfrac{\langle p \rangle}{\langle \rho \rangle} = c_0^2 \qquad \implies \qquad \cfrac{\partial\tilde{p}}{\partial t} = c_0^2 \cfrac{\partial\tilde{\rho}}{\partial t}$
The balance of mass can then be written as
$\cfrac{1}{c_0^2}\frac{\partial\tilde{p}}{\partial t} + \langle\rho\rangle\nabla\cdot\tilde{\mathbf{v}} = 0$
Dropping the tildes and defining $\rho_0 := \langle\rho\rangle$ gives us the commonly used expression for the balance of mass in an acoustic medium:
$\frac{\partial p}{\partial t} + \rho_0~c_0^2~\nabla\cdot\mathbf{v} = 0 ~.$
## Governing equations in cylindrical coordinates
If we use a cylindrical coordinate system $(r,\theta,z)$ with basis vectors $\mathbf{e}_r, \mathbf{e}_\theta, \mathbf{e}_z$, then the gradient of $p$ and the divergence of $\mathbf{v}$ are given by
\begin{align} \nabla p & = \cfrac{\partial p}{\partial r}~\mathbf{e}_r + \cfrac{1}{r}~\cfrac{\partial p}{\partial \theta}~\mathbf{e}_\theta + \cfrac{\partial p}{\partial z}~\mathbf{e}_z \\ \nabla\cdot\mathbf{v} & = \cfrac{\partial v_r}{\partial r} + \cfrac{1}{r}\left(\cfrac{\partial v_\theta}{\partial \theta} + v_r\right) + \cfrac{\partial v_z}{\partial z} \end{align}
where the velocity has been expressed as $\mathbf{v} = v_r~\mathbf{e}_r+v_\theta~\mathbf{e}_\theta+v_z~\mathbf{e}_z$.
The equations for the conservation of momentum may then be written as
$\rho_0~\left[\cfrac{\partial v_r}{\partial t}~\mathbf{e}_r+\cfrac{\partial v_\theta}{\partial t}~\mathbf{e}_\theta+\cfrac{\partial v_z}{\partial t}~\mathbf{e}_z\right] + \cfrac{\partial p}{\partial r}~\mathbf{e}_r + \cfrac{1}{r}~\cfrac{\partial p}{\partial \theta}~\mathbf{e}_\theta + \cfrac{\partial p}{\partial z}~\mathbf{e}_z = 0$
In terms of components, these three equations for the conservation of momentum in cylindrical coordinates are
$\rho_0~\cfrac{\partial v_r}{\partial t} + \cfrac{\partial p}{\partial r} = 0 ~;~~ \rho_0~\cfrac{\partial v_\theta}{\partial t} + \cfrac{1}{r}~\cfrac{\partial p}{\partial \theta} = 0 ~;~~ \rho_0~\cfrac{\partial v_z}{\partial t} + \cfrac{\partial p}{\partial z} = 0 ~.$
The equation for the conservation of mass can similarly be written in cylindrical coordinates as
$\cfrac{\partial p}{\partial t} + \kappa\left[\cfrac{\partial v_r}{\partial r} + \cfrac{1}{r}\left(\cfrac{\partial v_\theta}{\partial \theta} + v_r\right) + \cfrac{\partial v_z}{\partial z}\right] = 0 ~.$
### Time harmonic acoustic equations in cylindrical coordinates
The acoustic equations for the conservation of momentum and the conservation of mass are often expressed in time harmonic form (at fixed frequency). In that case, the pressures and the velocity are assumed to be time harmonic functions of the form
$p(\mathbf{x}, t) = \hat{p}(\mathbf{x})~e^{-i\omega t} ~;~~ \mathbf{v}(\mathbf{x}, t) = \hat{\mathbf{v}}(\mathbf{x})~e^{-i\omega t} ~;~~ i := \sqrt{-1}$
where $\omega$ is the frequency. Substitution of these expressions into the governing equations in cylindrical coordinates gives us the fixed frequency form of the conservation of momentum
$\cfrac{\partial\hat{p}}{\partial r} = i\omega~\rho_0~\hat{v}_r ~;~~ \cfrac{1}{r}~\cfrac{\partial\hat{p}}{\partial \theta} = i\omega~\rho_0~\hat{v}_\theta ~;~~ \cfrac{\partial\hat{p}}{\partial z} = i\omega~\rho_0~\hat{v}_z$
and the fixed frequency form of the conservation of mass
$\cfrac{i\omega \hat{p}}{\kappa} = \cfrac{\partial \hat{v}_r}{\partial r} + \cfrac{1}{r}\left(\cfrac{\partial \hat{v}_\theta}{\partial \theta} + \hat{v}_r\right) + \cfrac{\partial \hat{v}_z}{\partial z} ~.$
#### Special case: No z-dependence
In the special case where the field quantities are independent of the z-coordinate we can eliminate $v_r, v_\theta$ to get
$\frac{\partial^2 p}{\partial r^2} + \frac{1}{r}\frac{\partial p}{\partial r} + \frac{1}{r^2}~\frac{\partial^2 p}{\partial\theta^2} + \frac{\omega^2\rho_0}{\kappa}~p = 0$
Assuming that the solution of this equation can be written as
$p(r,\theta) = R(r)~Q(\theta)$
we can write the partial differential equation as
$\cfrac{r^2}{R}~\cfrac{d^2R}{dr^2} + \cfrac{r}{R}~\cfrac{dR}{dr} + \cfrac{r^2\omega^2\rho_0}{\kappa} = -\cfrac{1}{Q}~\cfrac{d^2Q}{d\theta^2}$
The left hand side is not a function of $\theta$ while the right hand side is not a function of $r$. Hence,
$r^2~\cfrac{d^2R}{dr^2} + r~\cfrac{dR}{dr} + \cfrac{r^2\omega^2\rho_0}{\kappa}~R = \alpha^2~R ~;~~ \cfrac{d^2Q}{d\theta^2} = -\alpha^2~Q$
where $\alpha^2$ is a constant. Using the substitution
$\tilde{r} \leftarrow \left(\omega\sqrt{\cfrac{\rho_0}{\kappa}}\right) r = k~r$
we have
$\tilde{r}^2~\cfrac{d^2R}{d\tilde{r}^2} + \tilde{r}~\cfrac{dR}{d\tilde{r}} + (\tilde{r}^2-\alpha^2)~R = 0 ~;~~ \cfrac{d^2Q}{d\theta^2} = -\alpha^2~Q$
The equation on the left is the Bessel equation which has the general solution
$R(r) = A_\alpha~J_\alpha(k~r) + B_\alpha~J_{-\alpha}(k~r)$
where $J_\alpha$ is the cylindrical Bessel function of the first kind and $A_\alpha, B_\alpha$ are undetermined constants. The equation on the right has the general solution
$Q(\theta) = C_\alpha~e^{i\alpha\theta} + D_\alpha~e^{-i\alpha\theta}$
where $C_\alpha,D_\alpha$ are undetermined constants. Then the solution of the acoustic wave equation is
$p(r,\theta) = \left[A_\alpha~J_\alpha(k~r) + B_\alpha~J_{-\alpha}(k~r)\right]\left(C_\alpha~e^{i\alpha\theta} + D_\alpha~e^{-i\alpha\theta}\right)$
Boundary conditions are needed at this stage to determine $\alpha$ and the other undetermined constants.
## References
1. ^ Douglas D. Reynolds. (1981). Engineering Principles in Acoustics, Allyn and Bacon Inc., Boston.
Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Acoustic_theory — Please support Wikipedia.
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Vezza D'Alba e Diano D'Alba: due serate sostenere il progetto umanitario Mosoq ... targatocn Fri, 07 Nov 2014 00:15:00 -0800 Si tratta di un AperiMusica: cibo e vino con le cover pop degli Acoustic Theory. Il secondo appuntamento sarà sabato 22 novembre ore 20.30 presso l'Azienda Agricola Cascina Rossa in via Cane Guido 24, Valle Talloria – Diano d'Alba, con il Concerto di ... La Stampa “Solidarietà in cantina” tra cibo e note La Stampa Sat, 08 Nov 2014 02:08:06 -0800 L'appuntamento è stasera dalle 18,30 alle 20, con un “Aperimusica” e le cover pop degli Acoustic Theory nell'azienda agricola Demarie di Vezza d'Alba, mentre sabato 22 novembre, ore 20,30, ci si sposterà a Cascina Rossa in Valle Talloria a Diano d'Alba ... WCPO Cincinnati and Milford students solve business, arts and community problems WCPO Tue, 27 May 2014 07:30:22 -0700 CINCINNATI – They helped decide whether Brazil is ready for the 2016 Olympics, how to lay out an art exhibit at Cincinnati Art Museum, how many Tri-Health hospital beds should be irradiated and whether it's worth the cost to buy or grow organic foods. Was Stonehenege built for sound effects? Telegraph.co.uk Thu, 16 Feb 2012 22:53:18 -0800 ... the mid-summer sunrise and mid-winter sunset and there is widespread agreement that it was used for cremation burials. “However, I don't think you'll find many archaeologists who know about Stonehenge giving this particular acoustic theory a lot of ... New tool for measuring frozen gas in ocean floor sediments EurekAlert (press release) Tue, 26 Feb 2013 07:28:09 -0800 Those measurements, and the acoustic theory we developed to interpret the data, provided exactly the foundation we needed to undertake this critically important study that will be relevant to the seabed in somewhat deeper waters. "As a greenhouse gas, ... Town Hall up with best in the world Stuff.co.nz Fri, 07 Dec 2012 14:41:15 -0800 Warren wrote in 2005 that Marshall was developing an acoustic theory of lateral reflections for auditoria. The town hall became "his most successful guinea pig". Hamish Hay told his fellow councillors that the expense of Warren's trip was justified by ... Was Stonehenge the result of an extraordinary hallucination after frenzied ... Daily Mail Thu, 16 Feb 2012 10:08:23 -0800 ... is aligned along the mid-summer sunrise and mid-winter sunset and there is widespread agreement that it was used for cremation burials. 'I don't think you'll find many archaeologists who know about Stonehenge giving this particular acoustic theory ... Air Force bristles at criticism of F-35 site selection process for Burlington vtdigger.org Tue, 03 Jul 2012 21:07:56 -0700 Last week a South Burlington official alleged the U.S. Air Force made a mistake in a scoring system used to rank Burlington International Airport as a top flight base for the new F-35 fighter jet. The Air Force responded ASAP with a press release ...
Limit to books that you can completely read online Include partial books (book previews) .gsc-branding { display:block; }
Oops, we seem to be having trouble contacting Twitter | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 102, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9585247039794922, "perplexity": 1084.8380639187872}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-49/segments/1416400380638.30/warc/CC-MAIN-20141119123300-00188-ip-10-235-23-156.ec2.internal.warc.gz"} |
https://www.physicsforums.com/threads/induced-voltage-with-coil-between-2-magnets.515499/ | # Induced voltage with coil between 2 magnets
1. Jul 20, 2011
### davenn
hi gang,
Just building a seismometer I have 2 x 2.5cm disc rare earth magnets spaced far enough apart for a coil of wire to move between them.
Would you expect there to be any difference in induced voltage into a coil between 2 magnets when the magnets are orientated to attract or repel ?
I'm thinking no difference, but really have no idea
see pic for idea of what I'm doing. ignore that fact the builder of shown unit is using 4 x disc magnets, 2 top and 2 bottom.
if there is a difference between the two options .... why ?
cheers
Dave
#### Attached Files:
• ###### coil_inserted2a.jpg
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Last edited by a moderator: Jul 20, 2011
2. Jul 20, 2011
### gerbi
Well.. can't see any picture. Got link to it ?
3. Jul 20, 2011
### davenn
I posted it and saw the pic, thought nothing more of it
then after your comment in the email, I visited the page and saw the pic was missing
Should be ok now :)
cheers
Dave
4. Jul 20, 2011
### gerbi
I'm not very familiar with that kind of stuff.. but.. from general elekctromagnetics:
I take that magnets are on opposite sides of coil and when there is earthquake you have some coil-magnets movement, correct ?
If yes then there are significant diffrences for diffrent magnets setups. You can observe signal because there is some movement between magnets and coils. Magnetic flux changes and this induces voltage in coil. The essence here is the magnetic flux generated by magnets. If they are set up in the same side N-S-N-S (or S-N-S-N) the flux is flowing, but if You set them up like N-S-S-N (or S-N-N-S) the magnetic flux will be near zero (it's like two sources set opposite). No flux = no signal.
5. Jul 20, 2011
### davenn
yes, thats correct. Some guys use horseshoe magnets. But strong and physically relatively small ones are not readily available. So the other main choice these days are to use several rare earth disc magnets.
Just for your info.... at the other end of the "red" assembly there are more magnets mounted. They have a piece of aluminium between them. This is used for dampening of the pendulum arm, so that it doesnt go into free natural oscillation. Else you are just recording the motion of the pendulum and not the earth.
Tecnically its the frame of the seismometer that is moving, not the pendulum, due to the large mass on the end of the pendulum arm. but because the pendulum isnt totally isolated from the frame it will start to oscillate as well.
Dave | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8026736378669739, "perplexity": 1880.1215662515417}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-36/segments/1471982295383.20/warc/CC-MAIN-20160823195815-00080-ip-10-153-172-175.ec2.internal.warc.gz"} |
https://paperswithcode.com/paper/subspace-sparse-representation | # Subspace-Sparse Representation
6 Jul 2015 · , ·
Given an overcomplete dictionary $A$ and a signal $b$ that is a linear combination of a few linearly independent columns of $A$, classical sparse recovery theory deals with the problem of recovering the unique sparse representation $x$ such that $b = A x$. It is known that under certain conditions on $A$, $x$ can be recovered by the Basis Pursuit (BP) and the Orthogonal Matching Pursuit (OMP) algorithms... In this work, we consider the more general case where $b$ lies in a low-dimensional subspace spanned by some columns of $A$, which are possibly linearly dependent. In this case, the sparsest solution $x$ is generally not unique, and we study the problem that the representation $x$ identifies the subspace, i.e. the nonzero entries of $x$ correspond to dictionary atoms that are in the subspace. Such a representation $x$ is called subspace-sparse. We present sufficient conditions for guaranteeing subspace-sparse recovery, which have clear geometric interpretations and explain properties of subspace-sparse recovery. We also show that the sufficient conditions can be satisfied under a randomized model. Our results are applicable to the traditional sparse recovery problem and we get conditions for sparse recovery that are less restrictive than the canonical mutual coherent condition. We also use the results to analyze the sparse representation based classification (SRC) method, for which we get conditions to show its correctness. read more
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Submit results from this paper to get state-of-the-art GitHub badges and help the community compare results to other papers. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7472413182258606, "perplexity": 390.791353256071}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-49/segments/1637964363226.68/warc/CC-MAIN-20211205221915-20211206011915-00008.warc.gz"} |
https://math.stackexchange.com/questions/2851589/scaling-a-part-of-a-function-without-altering-the-rest-of-it | # Scaling a part of a function without altering the rest of it
The question rises form the needing of plotting the function
$$I\left(x, y\right) = I_0\operatorname{sinc}^2\left(x\right)\operatorname{sinc}^2\left(y\right).$$ where $$\operatorname{sinc}(x) = \begin{cases}\frac{\sin(\pi x)}{\pi x} &\text{ if } x \neq 0\, \\ 1 &\text{ if } x = 0 \end{cases}$$ If you have already seen this function it's highly spiked at the origin of axes and decay very fast for values greater than 2 as you can see in the plot below
Now I would like to give a nice representation of the function by scaling the central spike (or equivalently the rest of the function in order to make the hight of subsequent fringes of interference. Initially I thought to scale the plot in the circle around the origin which contains the central spike, but this does nor really work well since it changes the relative scale in a discontinuous way, which results in a bad behaviour in the plot
So I thought that there could be a continuous function which can do the job I want, something for example like $${\rm scalingF}\left(x, y\right) \sim A\left(1-e^{-B\left(x^2 + y^2\right)}\right),$$
namely the positive opposite of a gaussian so that the outer part of the plot is stretched out more than the inner part, but unfortunately this method turns out in cutting the highest part, even if the rest of the plot is now precisely how I want it: $${\rm scalingF}\left(x, y\right) I\left(x, y\right)$$ gives
Does anybody know a way to scale just a part of this function maintaining it continuous and with a much more similar shape to the initial one (meaning that the profiles of the wave should remain the same)?
• Do you compute the scaling function yourself? If yes how? $1-e^{??}$ suffers from catastrophic cancellation for small arguments. If available use a function like expm1. – gammatester Jul 14 '18 at 13:53
• Have you tried plotting it on a logarithmic scale: $10\log_{10} I(x,y)$ ? – Andy Walls Jul 14 '18 at 14:14
• @gammatester I can't understand your question, but the function $$1-e^{-x^2}$$ is just a gaussian curve reflected along the x axis and shifted above of one, so no "catastrophic cancellation" occurs for me ;), but maybe I'm misunderstanding what you want to say! – opisthofulax Jul 14 '18 at 14:18
• If $x$ is small you have $1-e^{-x^2}=x^2-x^4/2$ but if you compute e.g. with IEEE double precision you have $e^{-x^2}\approx 1$, and the difference suffers from cancellation. But as Théophile has written, this is not your main problem. – gammatester Jul 14 '18 at 14:33
Your Gaussian idea is interesting; the reason it doesn't work is that the scaling function vanishes at $(0,0)$. To fix this, how about simply adding $1$:
$${\rm scalingF}\left(x, y\right) = A\left(1-e^{-B\left(x^2 + y^2\right)}\right) + 1$$
so that ${\rm scalingF}(0, 0) = 1$, and far enough from the origin, ${\rm scalingF}(x,y) \approx A + 1$.
Now, maybe you want to preserve the height everywhere except near the origin. In that case, we just scale down again (and I've used $A - 1$ as a multiplier instead of $A$ so that it's a bit cleaner):
$${\rm scalingF}\left(x, y\right) = \frac{(A-1)\left(1-e^{-B\left(x^2 + y^2\right)}\right) + 1}A$$
This will scale the origin to $1/A$ its original height while preserving the periphery.
• Thanks for your answer, but the problem of the gaussian curve is that augmenting $A$ will cause anyway to make appear a gaussian pattern on the top of the spike, if I try to zoom the outer region too much (for which I cannot change so much $B$ otherwise the effect of magnifying get lost). I'm thinking that I do not need a spiked curve but maybe something that has a plateau instead of the spike of the gaussian gurve and decreases similarly fast (in this case increase). – opisthofulax Jul 14 '18 at 14:54
• I managed a nice solution with arctan function, I'll post it right now ;) – opisthofulax Jul 14 '18 at 15:17
• @opisthofulax Interesting... glad you figured it out! – Théophile Jul 15 '18 at 3:10
So, I started considering that the gaussian curve is not precisely what I did need. In fact the scaling with this function tends to create an "inverse spike" in the function, rather than scaling with the same height all the point of a function in a certain circular/squared region. This behaviour can be easily visualised by plotting the suggested function from @Théophile with A and B parameters set in order to scale enough the whole graph except from the central spike: $$I\cdot{\rm scalingF}\left(x, y\right) = I\cdot\frac{(A-1)\left(1-e^{-B\left(x^2 + y^2\right)}\right) + 1}A$$ will produce (e.g for $A\gg1$, because I need a big scaling factor, and $B\approx.1$ as I just need a small region centered around the origin)
That's because it's scaling the center to $1/A$, but the stuff around is not scaled the same nor less, but more.
Then a function which stays the same for and interval and then grows really fast is needed. Plus, the region not around the axes (the blackest ones) must be scaled more than the region along the axes. Now, by knowing that a $\operatorname{rect}(x)$ function will create a bad discontinuity (the first solution tried by me), I thought that the nicest solution was a "continuous" $\operatorname{rect}(x)$ function, which can easily be obtained by thinking as the sum of two $\arctan(x)$ functions "going in opposite directions"
in which the arguments of $\arctan(x)$ has been choosen for cutting intensity in the region $\approx[-3.5, 3.5]$ which is more or less the one in which the original function is having that big spike. At is point there are two possibilities. The first is to multiply the two "$\operatorname{rectarctan}(x)$" in order to get a distribution of intensity $${\rm scalingF1}\left(x, y\right) = \arctan[5 x - 20] - \arctan[5 x + 20] + 1.01 \pi)\cdot (\arctan[5 y - 20] - \arctan[5 y + 20] + 1.01 \pi)$$
where the factor of pies control the proportion between the central spike and the rest of the scaled graph such as if they become too big the scaling quantity on the central spike will become greater than the one on the other part.
Anyway, as it clear to see from figure 3 the path along the axis is not stretched out, so it can be annoying to have the spikes far from the axes bigger than the one along the axes as you can see below
But a simple modification is possible in order to remedy this little bug, by substituting the multiplication in the scaling function by the sum $${\rm scalingF2}\left(x, y\right) = \arctan[5 x - 20] - \arctan[5 x + 20] + 1.01 \pi)\cdot (\arctan[5 y - 20] - \arctan[5 y + 20] + 1.01 \pi)$$ which graph is
This function modulates both contents along the axes and contents outside, by cutting high intensities in the center, as it's possible to see in the final output | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 6, "x-ck12": 0, "texerror": 0, "math_score": 0.8452489972114563, "perplexity": 287.2842569193279}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-26/segments/1560627997508.21/warc/CC-MAIN-20190616002634-20190616024634-00089.warc.gz"} |
https://tug.org/pipermail/texworks/2011q1/003966.html | # [texworks] once more: problems with eps and ps figures in texworks
Bruno Voisin bvoisin at me.com
Tue Mar 22 15:21:40 CET 2011
```Le 22 mars 2011 à 15:05, Herbert Schulz a écrit :
> On Mar 21, 2011, at 4:04 PM, Vandebroek, Martina wrote:
>
>> \usepackage[dvips]{graphicx}
>> \usepackage{subfigure}
>> \usepackage{epsfig}
>> \usepackage{epstopdf}
>> ...
>>
>
> If you are compiling with the default pdflatex you should NOT be using the [dvips] option to the graphicx package. As a matter of fact, unless you are using latex with dvipdfm(x) or some other back end that dvips->ps2pdf there is no need to give any driver options.
>
> Next, how recent is your TeX distribution? In TL2010 (I'm not familiar with MikTeX versions) you won't need to use epstopdf (it's loaded in restricted mode by the graphicx package). Why are you including the epsfig package?
It seems dangerous to use epsfig and epstopdf together, their purposes are antagonistic: epsfig deals with EPS files, and epstopdf bypasses them by calling GhostScript for conversion to PDF before processing by pdfTeX.
That said, why are you using pdfLaTeX? From your preamble, it looks like you'd be better off using LaTeX + dvips + Ghostscript. See | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9279725551605225, "perplexity": 8676.521199631186}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323585203.61/warc/CC-MAIN-20211018124412-20211018154412-00383.warc.gz"} |
http://stats.seandolinar.com/tag/statistics/ | # Calculating Z-Scores [with R code]
I’ve included the full R code and the data set can be found on UCLA’s Stats Wiki
Normal distributions are convenient because they can be scaled to any mean or standard deviation meaning you can use the exact same distribution for weight, height, blood pressure, white-noise errors, etc. Obviously, the means and standard deviations of these measurements should all be completely different. In order to get the distributions standardized, the measurements can be changed into z-scores.
Z-scores are a stand-in for the actual measurement, and they represent the distance of a value from the mean measured in standard deviations. So a z-score of 2.0 means the measurement is 2 standard deviations away from the mean.
To demonstrate how this is calculated and used, I found a height and weight data set on UCLA’s site. They have height measurements from children from Hong Kong. Unfortunately, the site doesn’t give much detail about the data, but it is an excellent example of normal distribution as you can see in the graph below. The red line represents the theoretical normal distribution, while the blue area chart reflects a kernel density estimation of the data set obtained from UCLA. The data set doesn’t deviate much from the theoretical distribution.
The z-scores are also listed on this normal distribution to show how the actual measurements of height correspond to the z-scores, since the z-scores are simple arithmetic transformations of the actual measurements. The first step to find the z-score is to find the population mean and standard deviation. It should be noted that the sd function in R uses the sample standard deviation and not the population standard deviation, though with 25,000 samples the different is rather small.
Using just the population mean [μ = 67.99] and standard deviation [σ = 1.90], you can calculate the z-score for any given value of x. In this example I’ll use 72 for x.
$z = \frac{x - \mu}{\sigma}$
This gives you a z-score of 2.107. To put this tool to use, let’s use the z-score to find the probability of finding someone who is 72 inches [6-foot] tall. [Remember this data set doesn’t apply to adults in the US, so these results might conflict with everyday experience.] The z-score will be used to determine the area [probability] underneath the distribution curve past the z-score value that we are interested in.
[One note is that you have to specify a range (72 to infinity) and not a single value (72). If you wanted to find people who are exactly 6-foot, not taller than 6-foot, you would have to specify the range of 71.5 to 72.5 inches. This is another problem, but this has everything to do with definite integrals intervals if you are familiar with Calc I.]
The above graph shows the area we intend to calculate. The blue area is our target, since it represents the probability of finding someone taller than 6-foot. The yellow area represents the rest of the population or everyone is is under 6-feet tall. The z-score and actual height measurements are both given underscoring the relationship between the two.
Typically in an introductory stats class, you’d use the z-score and look it up in a table and find the probability that way. R has a function ‘pnorm’ which will give you a more precise answer than a table in a book. [‘pnorm’ stands for “probability normal distribution”.] Both R and typical z-score tables will return the area under the curve from -infinity to value on the graph this is represented by the yellow area. In this particular problem, we want to find the blue area. The solution to this is an easy arithmetic function. The area under the curve is 1, so by subtracting the yellow area from 1 will give you the area [probability] for the blue area.
Yellow Area:
Blue Area [TARGET]:
Both of these techniques in R will yield the same answer of 1.76%. I used both methods, to show that R has some versatility that traditional statistics tables don’t have. I personally find statistics tables antiquated, since we have better ways to determine it, and the table doesn’t help provide any insight over software solutions.
Z-scores are useful when relating different measurement distributions to each acting as a ‘common denominator’. The z-scores are used extensively for determining area underneath the curve when using text book tables, and also can be easily used in programs such as R. Some statistical hypothesis tests are based on z-scores and the basic principles of finding the area beyond some value.
# OLS Derivation
Ordinary Least Squares (OLS) is a great low computing power way to obtain estimates for coefficients in a linear regression model. I wanted to detail the derivation of the solution since it can be confusing for anyone not familiar with matrix calculus.
First, the initial matrix equation is setup below. With X being a matrix of the data’s p covariates plus the regression constant. [This will be represented as a column of ones if you were to look at the data in the X matrix.] Y is the column matrix of the target variable and β is the column matrix of unknown coefficients. e is a column matrix of the residuals.
$\mathbf{Y = X} \boldsymbol{\beta} + \boldsymbol{e}$
Before manipulating the equation it is important to note you are not solving for X or Y, but instead β and will do this by minimizing the sum of squares for the residuals (SSE). So the equation can be rewritten by moving the error term to the left side of the equation.
$\boldsymbol{e} = \mathbf{Y - X} \boldsymbol{\beta}$
The SSE can be written as the product of the transposed residual column vector and its original column vector. [This is actually how you would obtain the sum of squares for any vector.]
$\mathrm{SSE} = \boldsymbol{e}'\boldsymbol{e}$
Since you transpose and multiply one side of the equation, you have to follow suit on the other side. Yielding
$\boldsymbol{e'e} = (\mathbf{Y - X} \boldsymbol{\beta})'(\mathbf{Y - X} \boldsymbol{\beta})$
The transpose operator can be distributed through out the quantity on the right side, so the right side can be multiplied out.
$\boldsymbol{e'e} = (\mathbf{Y' - \boldsymbol{\beta}'X'})(\mathbf{Y - X} \boldsymbol{\beta})$
Using the rule that A’X = X’A, you can multiple out the right side and simplify it.
$\boldsymbol{e'e} = (\mathbf{Y'Y - Y'X\boldsymbol{\beta} - \boldsymbol{\beta}'X'Y} + \boldsymbol{\beta'\mathbf{X'X}\beta})$
$\boldsymbol{e'e} = (\mathbf{Y'Y - \boldsymbol{\beta}'X'Y - \boldsymbol{\beta}'X'Y} + \boldsymbol{\beta'\mathbf{X'X}\beta})$
$\boldsymbol{e'e} = (\mathbf{Y'Y - 2\boldsymbol{\beta}'X'Y} + \boldsymbol{\beta'\mathbf{X'X}\beta})$
To minimize the SSE, you have to take the partial derivative relative to β. Any terms without a β term in them will go to zero. Using the transpose rule from before you can see how the middle term yields -2X’Y using differentiation rules from Calc1. The last term is a bit tricky, but it derives to +2X’Xβ.
$\frac{\delta\boldsymbol{e'e}}{\delta\boldsymbol{\beta}} = \frac{\delta\mathbf{Y'Y}}{\delta\boldsymbol{\beta}} - \frac{2\boldsymbol{\beta}'\mathbf{X'Y}}{\delta\boldsymbol{\beta}} + \frac{\delta\boldsymbol{\beta'\mathbf{X'X}\beta}}{\delta\boldsymbol{\beta}}$
$\frac{\delta\boldsymbol{e'e}}{\delta\boldsymbol{\beta}} = - 2\mathbf{X'Y} + 2\boldsymbol{\mathbf{X'X}\beta}$
To find the minimum (it will never be a maximum if you have all the requirements for OLS fulfilled), the derivative of the SSE is set to zero.
$0 = - 2\mathbf{X'Y} + 2\mathbf{X'X}\boldsymbol{\beta}$
$0 = \mathbf{- X'Y} + \mathbf{X'X}\boldsymbol{\beta}$
Using some basic linear algebra and multiplying both sides by the inverse of (X’X)…
$(\mathbf{X'X})^{-1}\mathbf{X'X}\boldsymbol{\beta} = (\mathbf{X'X})^{-1}\mathbf{X'Y}$
…yields the solution for β
$\boldsymbol{\beta} = (\mathbf{X'X})^{-1}\mathbf{X'Y}$
References:
Chatterjee, S & Hadi, A. (2012). Regression analysis by example. Hoboken, NJ: John Wiley & Sons, Inc.
# Count Data Distribution Primer — Binomial / Negative Binomial / Poisson
Count data is exclusively whole number data where each increment represents one of something. It could be a car accident, a run in baseball, or an insurance claim. The critical thing here is that these are discrete, distinct items. Count data behaves differently than continuous data, and the distribution [frequency of of different values] is different between the two. Random continuous data typically follows the normal distribution, which is the bell curve everyone remembers from high school grade systems. [Which is a really bad way to grade, but I digress.] Count data generally follows the Binomial/Negative Binomial/Poisson distribution depending what context you are viewing the data; all three distributions are mathematically related.
Binomial Distribution:
The binomial distribution (BD) is the collection of probabilities of getting a certain number of successes in a given number of trials specifically measuring Bernoulli trials [a yes/no event similar to a coin flip, but it’s not necessarily 50/50]. My favorite example to understand the binomial distribution is using it to determine the probability that you’d get exactly 5 HEADS if you flipped a coin 10 times [it’s NOT 50%!].
It’s actually 24.61%. The probability of getting heads in any given coin flip is 50%, but over 10 flips, you’ll only get exactly 5 HEADS and 5 TAILS about 25% of the time. The equation below gives the two popular notations for the binomial probability mass function. $n$ is total number of trials. [the graph above used n=10]. $r$ is the number of successes you want to know the probability for. You calculate this function for each number of HEADS [0-10] for $r$ to get the distribution above. $p$ is the simple probability for each event. [$p$ = .5 for the coin flip.]
$P(X=r) = {{n}\choose{r}} p^{r} (1-p)^{n-r} = \frac{n!}{r!(n-r)!} p^{r} (1-p)^{n-r}$
The equation has three parts. The first part is the combination ${{n}\choose{r}}$, which is the number of combinations when you have $n$ total items taken $r$ at a time. Combination disregard order, so the set {1, 4, 9} is the same as {4, 9, 1}. This part of the equation tells you how many possible ways there are to get to a certain outcome since there are many way to get 5 HEADS in 10 tosses. Since ${{10}\choose{5}}$ is larger than any other combination, 5 HEADS will have the largest probability.
There are two more terms in the equation. $p^r$ is joint probability of getting r successes in a particular order, and $(1-p)^{n-r}$ is the corresponding probably of also getting the failures also in a particular order. I find it helpful to conceptualize the equation as having three parts accounting for different things: total combinations of successes and failures, the probabilities of successes, and the probability of failures.
Negative Binomial Distribution:
While there is a good reason for it, the name of the negative binomial distribution (NBD) is confusing. Nothing I will present will involve making anything negative so, let’s just get that out of the way and ignore it. The binomial distribution uses the probability of successes in the total number of ATTEMPTS. To contrast this, the negative binomial distribution uses the probability that a certain number of FAILURES occur before the $r$th SUCCESS. This has many applications specifically when a sequence terminates after the $r$th success such as modeling the probability that you will sell out of the 25 cups of lemonade you have stocked for a given number of cars that pass by. The idea is that you would pack up your lemonade stand after you sell out, so cars that would pass by after the final success won’t matter. Another good example is modeling the win probability of a 7-game sports playoff series. The team that wins the series must win 4 games and specifically the last game played in the series, since the playoff series terminates after one team reaches 4 wins.
One of the more important restrictions on the NBD is that the last event must be a success. Going back to the sports playoff series example, the team that wins the series will NEVER lose the last game. With the 10 coin-flip example, the BD was looking for the probability of getting a certain number of HEADS within a set number of coin flips. Using the NBD, we will look for the probability of 5 HEADS before getting a certain number of TAILS. The total number of flips will not ALWAYS equal 10 and actually exceeds 10 as seen below.
The probability mass function that describes the NBD graph above is given below:
$P(X=k) = {{r+k-1}\choose{k}} p^{r} (1-p)^{k}$
The equation for the NBD has the same parts as the BD: the combinations, the success, and the failures. In the NBD case the combinations are less than the BD [for the same total number of coin flips]. This is because the last outcome is held fix at a success. The probability of success and failure parts of the equation are conceptually the same as the BD. The failure portion is written differently because the number of failures is a parameter $k$ instead of a derived quantity like [$n-r$].
Poisson Distribution:
The Poisson Distribution (PD) is directly related to both the BD and the NBD, because it is the limiting case of both of them. As the number of trials goes to infinity, then the Poisson distribution emerges. The graph for the PD will look similar to the NBD or the BD, and there is no example comparing the coin flip since there has to be some non-discrete process like traffic flow or earthquakes. The major difference is not what is represented, but how it is viewed and calculated. The Poisson distribution is described by the equation:
$P(X = x) = \frac{e^{-\lambda}\lambda^x}{x!}$
$\lambda$ is the expected value [or the mean] for an event and $x$ is the count value. If you knew an average of 0.2 car crashes happen at an intersection at a given day then you could solve the equation for $x$ = {0, 1, 2, 3, 4, 5, … } and get the PD for the problem.
One of the restrictions and major issues with the use of the PD is that the model assumes the mean and the variance are equal. In most real data instances the variance is greater than the mean, so the PD tends to favor more values around the expected value than real data reflects.
If you are interested in the derivations and math behind these I recommend this site: http://statisticalmodeling.wordpress.com/. I feel like they explain the derivation of the negative binomial better than most places I’ve found. It addresses why it’s called the NEGATIVE binomial distribution as well. The site also contains derivations of the PD being the limiting case of the BD and NBD. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 36, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8359950184822083, "perplexity": 335.4697846464676}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-13/segments/1490218189680.78/warc/CC-MAIN-20170322212949-00563-ip-10-233-31-227.ec2.internal.warc.gz"} |
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Jun19 comment Why can't a rope be pulled completely straight? $\cos(\theta)$ does not go to zero as $\theta$ goes to zero, it goes to $1$. May19 comment What is negative about negative energy states in the Dirac equation? If you go back to the post he references, it is a bit more clear that he is mixing and matching the two pictures (electrons/holes, positron/electron), instead of keeping them separate. May19 comment What is negative about negative energy states in the Dirac equation? "Holes in the sea are positive-energy positrons, equivalent to the action of the positron creation operator on the vacuum." pretty much, just make sure the two pictures (negative/positive energy electrons aka. holes/electrons and positrons/electrons) are kept very separate in your mind. Jul6 comment Why aren't there compression waves in electromagnetic fields? Something to keep in mind is that longitudinal waves are actually possible in EM, however they require a medium in which to propagate (you can't do this in a vacuum). Typically they show up in waveguides in a dielectric. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5589428544044495, "perplexity": 949.5784799334766}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-35/segments/1408500822560.65/warc/CC-MAIN-20140820021342-00222-ip-10-180-136-8.ec2.internal.warc.gz"} |
http://www.askmehelpdesk.com/plumbing/toilet-phantom-flushes-613187.html | My toilet makes a phantom flushing noise every so often day and night. The water runs in the toilet slightly but it doesn`t actually flush. It is a Kohler and I believe it is a water conserving unit-it was in the house when we bought it 9 years ago but only the last year or so it has been doing this noise. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6048451066017151, "perplexity": 1102.6792770653904}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-10/segments/1393999668222/warc/CC-MAIN-20140305060748-00064-ip-10-183-142-35.ec2.internal.warc.gz"} |
http://mymathforum.com/complex-analysis/338221-find-values-sin-inverse-sqrt-5-a.html | My Math Forum find the values of sin inverse sqrt 5
Complex Analysis Complex Analysis Math Forum
December 22nd, 2016, 02:53 PM #1 Newbie Joined: Dec 2016 From: egypt Posts: 3 Thanks: 0 find the values of sin inverse sqrt 5 Find the values of sin inverse sqrt 5 I'm stuck with this one; please someone help me. Last edited by skipjack; December 24th, 2016 at 05:34 AM.
December 22nd, 2016, 03:21 PM #2 Senior Member Joined: Sep 2015 From: Southern California, USA Posts: 1,481 Thanks: 744 what is the range of the sine function? what is the approximate value of $\sqrt{5}$ ? do you see a problem here? unless you mean $\sin\left(\dfrac{1}{\sqrt{5}}\right)$ is that what you mean?
December 22nd, 2016, 05:52 PM #3 Global Moderator Joined: Oct 2008 From: London, Ontario, Canada - The Forest City Posts: 7,590 Thanks: 936 Math Focus: Elementary mathematics and beyond $\displaystyle y=\sin^{-1}(\sqrt5)$ $\displaystyle \sin(y)=\sqrt5$ $\displaystyle e^{iy}-e^{-iy}=2i\sqrt5$ $\displaystyle \frac{e^{2iy}-1}{e^{iy}}=2i\sqrt5\Rightarrow e^{2iy}-2i\sqrt5e^{iy}-1=0\implies y=\log(i(\sqrt5\pm2))/i$ $\displaystyle \sin^{-1}(\sqrt5)=\log(i(\sqrt5\pm2))/i+2k\pi,k\in\mathbf{Z}$
December 23rd, 2016, 10:18 AM #4 Newbie Joined: Dec 2016 From: egypt Posts: 3 Thanks: 0 ty so much
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http://www.sagemath.org/doc/reference/geometry/sage/rings/polynomial/groebner_fan.html | # Groebner Fans¶
Sage provides much of the functionality of gfan, which is a software package whose main function is to enumerate all reduced Groebner bases of a polynomial ideal. The reduced Groebner bases yield the maximal cones in the Groebner fan of the ideal. Several subcomputations can be issued and additional tools are included. Among these the highlights are:
• Commands for computing tropical varieties.
• Interactive walks in the Groebner fan of an ideal.
• Commands for graphical renderings of Groebner fans and monomial ideals.
AUTHORS:
• Anders Nedergaard Jensen: Wrote the gfan C++ program, which implements algorithms many of which were invented by Jensen, Komei Fukuda, and Rekha Thomas. All the underlying hard work of the Groebner fans functionality of Sage depends on this C++ program.
• William Stein (2006-04-20): Wrote first version of the Sage code for working with Groebner fans.
• Tristram Bogart: the design of the Sage interface to gfan is joint work with Tristram Bogart, who also supplied numerous examples.
• Marshall Hampton (2008-03-25): Rewrote various functions to use gfan-0.3. This is still a work in progress, comments are appreciated on [email protected] (or personally at [email protected]).
EXAMPLES:
sage: x,y = QQ['x,y'].gens()
sage: i = ideal(x^2 - y^2 + 1)
sage: g = i.groebner_fan()
sage: g.reduced_groebner_bases()
[[x^2 - y^2 + 1], [-x^2 + y^2 - 1]]
TESTS:
sage: x,y = QQ['x,y'].gens()
sage: i = ideal(x^2 - y^2 + 1)
sage: g = i.groebner_fan()
True
REFERENCES:
class sage.rings.polynomial.groebner_fan.GroebnerFan(I, is_groebner_basis=False, symmetry=None, verbose=False)
This class is used to access capabilities of the program Gfan. In addition to computing Groebner fans, Gfan can compute other things in tropical geometry such as tropical prevarieties.
INPUT:
• I - ideal in a multivariate polynomial ring
• is_groebner_basis - bool (default False). if True, then I.gens() must be a Groebner basis with respect to the standard degree lexicographic term order.
• symmetry - default: None; if not None, describes symmetries of the ideal
• verbose - default: False; if True, printout useful info during computations
EXAMPLES:
sage: R.<x,y,z> = QQ[]
sage: I = R.ideal([x^2*y - z, y^2*z - x, z^2*x - y])
sage: G = I.groebner_fan(); G
Groebner fan of the ideal:
Ideal (x^2*y - z, y^2*z - x, x*z^2 - y) of Multivariate Polynomial Ring in x, y, z over Rational Field
Here is an example of the use of the tropical_intersection command, and then using the RationalPolyhedralFan class to compute the Stanley-Reisner ideal of the tropical prevariety:
sage: R.<x,y,z> = QQ[]
sage: I = R.ideal([(x+y+z)^3-1,(x+y+z)^3-x,(x+y+z)-3])
sage: GF = I.groebner_fan()
sage: PF = GF.tropical_intersection()
sage: PF.rays()
[[-1, 0, 0], [0, -1, 0], [0, 0, -1], [1, 1, 1]]
sage: RPF = PF.to_RationalPolyhedralFan()
sage: RPF.Stanley_Reisner_ideal(PolynomialRing(QQ,4,'A, B, C, D'))
Ideal (A*B, A*C, B*C*D) of Multivariate Polynomial Ring in A, B, C, D over Rational Field
buchberger()
Computes and returns a lexicographic reduced Groebner basis for the ideal.
EXAMPLES:
sage: R.<x,y,z> = PolynomialRing(QQ,3)
sage: G = R.ideal([x - z^3, y^2 - x + x^2 - z^3*x]).groebner_fan()
sage: G.buchberger()
[-z^3 + y^2, -z^3 + x]
characteristic()
Return the characteristic of the base ring.
EXAMPLES:
sage: R.<x,y,z> = PolynomialRing(QQ,3)
sage: i1 = ideal(x*z + 6*y*z - z^2, x*y + 6*x*z + y*z - z^2, y^2 + x*z + y*z)
sage: gf = i1.groebner_fan()
sage: gf.characteristic()
0
dimension_of_homogeneity_space()
Return the dimension of the homogeneity space.
EXAMPLES:
sage: R.<x,y> = PolynomialRing(QQ,2)
sage: G = R.ideal([y^3 - x^2, y^2 - 13*x]).groebner_fan()
sage: G.dimension_of_homogeneity_space()
0
gfan(cmd='bases', I=None, format=True)
Returns the gfan output as a string given an input cmd; the default is to produce the list of reduced Groebner bases in gfan format.
EXAMPLES:
sage: R.<x,y> = PolynomialRing(QQ,2)
sage: gf = R.ideal([x^3-y,y^3-x-1]).groebner_fan()
sage: gf.gfan()
'Q[x,y]\n{{\ny^9-1-y+3*y^3-3*y^6,\nx+1-y^3}\n,\n{\ny^3-1-x,\nx^3-y}\n,\n{\ny-x^3,\nx^9-1-x}\n}\n'
homogeneity_space()
Return the homogeneity space of a the list of polynomials that define this Groebner fan.
EXAMPLES:
sage: R.<x,y> = PolynomialRing(QQ,2)
sage: G = R.ideal([y^3 - x^2, y^2 - 13*x]).groebner_fan()
sage: H = G.homogeneity_space()
ideal()
Return the ideal the was used to define this Groebner fan.
EXAMPLES:
sage: R.<x1,x2> = PolynomialRing(QQ,2)
sage: gf = R.ideal([x1^3-x2,x2^3-2*x1-2]).groebner_fan()
sage: gf.ideal()
Ideal (x1^3 - x2, x2^3 - 2*x1 - 2) of Multivariate Polynomial Ring in x1, x2 over Rational Field
interactive(*args, **kwds)
See the documentation for self[0].interactive(). This does not work with the notebook.
EXAMPLES:
sage: print "This is not easily doc-testable; please write a good one!"
This is not easily doc-testable; please write a good one!
maximal_total_degree_of_a_groebner_basis()
Return the maximal total degree of any Groebner basis.
EXAMPLES:
sage: R.<x,y> = PolynomialRing(QQ,2)
sage: G = R.ideal([y^3 - x^2, y^2 - 13*x]).groebner_fan()
sage: G.maximal_total_degree_of_a_groebner_basis()
4
minimal_total_degree_of_a_groebner_basis()
Return the minimal total degree of any Groebner basis.
EXAMPLES:
sage: R.<x,y> = PolynomialRing(QQ,2)
sage: G = R.ideal([y^3 - x^2, y^2 - 13*x]).groebner_fan()
sage: G.minimal_total_degree_of_a_groebner_basis()
2
mixed_volume()
Returns the mixed volume of the generators of this ideal (i.e. this is not really an ideal property, it can depend on the generators used). The generators must give a square system (as many polynomials as variables).
EXAMPLES:
sage: R.<x,y,z> = QQ[]
sage: example_ideal = R.ideal([x^2-y-1,y^2-z-1,z^2-x-1])
sage: gf = example_ideal.groebner_fan()
sage: mv = gf.mixed_volume()
sage: mv
8
sage: R2.<x,y> = QQ[]
sage: g1 = 1 - x + x^7*y^3 + 2*x^8*y^4
sage: g2 = 2 + y + 3*x^7*y^3 + x^8*y^4
sage: example2 = R2.ideal([g1,g2])
sage: example2.groebner_fan().mixed_volume()
15
number_of_reduced_groebner_bases()
Return the number of reduced Groebner bases.
EXAMPLES:
sage: R.<x,y> = PolynomialRing(QQ,2)
sage: G = R.ideal([y^3 - x^2, y^2 - 13*x]).groebner_fan()
sage: G.number_of_reduced_groebner_bases()
3
number_of_variables()
Return the number of variables.
EXAMPLES:
sage: R.<x,y> = PolynomialRing(QQ,2)
sage: G = R.ideal([y^3 - x^2, y^2 - 13*x]).groebner_fan()
sage: G.number_of_variables()
2
sage: R = PolynomialRing(QQ,'x',10)
sage: R.inject_variables(globals())
Defining x0, x1, x2, x3, x4, x5, x6, x7, x8, x9
sage: G = ideal([x0 - x9, sum(R.gens())]).groebner_fan()
sage: G.number_of_variables()
10
polyhedralfan()
Returns a polyhedral fan object corresponding to the reduced Groebner bases.
EXAMPLES:
sage: R3.<x,y,z> = PolynomialRing(QQ,3)
sage: gf = R3.ideal([x^8-y^4,y^4-z^2,z^2-1]).groebner_fan()
sage: pf = gf.polyhedralfan()
sage: pf.rays()
[[0, 0, 1], [0, 1, 0], [1, 0, 0]]
reduced_groebner_bases()
EXAMPLES:
sage: R.<x,y,z> = PolynomialRing(QQ, 3, order='lex')
sage: G = R.ideal([x^2*y - z, y^2*z - x, z^2*x - y]).groebner_fan()
sage: X = G.reduced_groebner_bases()
sage: len(X)
33
sage: X[0]
[z^15 - z, y - z^11, x - z^9]
sage: X[0].ideal()
Ideal (z^15 - z, y - z^11, x - z^9) of Multivariate Polynomial Ring in x, y, z over Rational Field
sage: X[:5]
[[z^15 - z, y - z^11, x - z^9],
[-y + z^11, y*z^4 - z, y^2 - z^8, x - z^9],
[-y^2 + z^8, y*z^4 - z, y^2*z^3 - y, y^3 - z^5, x - y^2*z],
[-y^3 + z^5, y*z^4 - z, y^2*z^3 - y, y^4 - z^2, x - y^2*z],
[-y^4 + z^2, y^6*z - y, y^9 - z, x - y^2*z]]
sage: R3.<x,y,z> = PolynomialRing(GF(2477),3)
sage: gf = R3.ideal([300*x^3-y,y^2-z,z^2-12]).groebner_fan()
sage: gf.reduced_groebner_bases()
[[z^2 - 12, y^2 - z, x^3 + 933*y],
[-y^2 + z, y^4 - 12, x^3 + 933*y],
[z^2 - 12, -300*x^3 + y, x^6 - 1062*z],
[-828*x^6 + z, -300*x^3 + y, x^12 + 200]]
render(file=None, larger=False, shift=0, rgbcolor=(0, 0, 0), polyfill=<function max_degree at 0x7f66840f5410>, scale_colors=True)
Render a Groebner fan as sage graphics or save as an xfig file.
More precisely, the output is a drawing of the Groebner fan intersected with a triangle. The corners of the triangle are (1,0,0) to the right, (0,1,0) to the left and (0,0,1) at the top. If there are more than three variables in the ring we extend these coordinates with zeros.
INPUT:
• file - a filename if you prefer the output saved to a file. This will be in xfig format.
• shift - shift the positions of the variables in the drawing. For example, with shift=1, the corners will be b (right), c (left), and d (top). The shifting is done modulo the number of variables in the polynomial ring. The default is 0.
• larger - bool (default: False); if True, make the triangle larger so that the shape of of the Groebner region appears. Affects the xfig file but probably not the sage graphics (?)
• rgbcolor - This will not affect the saved xfig file, only the sage graphics produced.
• polyfill - Whether or not to fill the cones with a color determined by the highest degree in each reduced Groebner basis for that cone.
• scale_colors - if True, this will normalize color values to try to maximize the range
EXAMPLES:
sage: R.<x,y,z> = PolynomialRing(QQ,3)
sage: G = R.ideal([y^3 - x^2, y^2 - 13*x,z]).groebner_fan()
sage: test_render = G.render()
sage: R.<x,y,z> = PolynomialRing(QQ,3)
sage: G = R.ideal([x^2*y - z, y^2*z - x, z^2*x - y]).groebner_fan()
sage: test_render = G.render(larger=True)
TESTS:
Testing the case where the number of generators is < 3. Currently, this should raise a NotImplementedError error.
sage: R.<x,y> = PolynomialRing(QQ, 2)
sage: R.ideal([y^3 - x^2, y^2 - 13*x]).groebner_fan().render()
Traceback (most recent call last):
...
NotImplementedError
render3d(verbose=False)
For a Groebner fan of an ideal in a ring with four variables, this function intersects the fan with the standard simplex perpendicular to (1,1,1,1), creating a 3d polytope, which is then projected into 3 dimensions. The edges of this projected polytope are returned as lines.
EXAMPLES:
sage: R4.<w,x,y,z> = PolynomialRing(QQ,4)
sage: gf = R4.ideal([w^2-x,x^2-y,y^2-z,z^2-x]).groebner_fan()
sage: three_d = gf.render3d()
TESTS:
Now test the case where the number of generators is not 4. Currently, this should raise a NotImplementedError error.
sage: P.<a,b,c> = PolynomialRing(QQ, 3, order="lex")
sage: sage.rings.ideal.Katsura(P, 3).groebner_fan().render3d()
Traceback (most recent call last):
...
NotImplementedError
ring()
Return the multivariate polynomial ring.
EXAMPLES:
sage: R.<x1,x2> = PolynomialRing(QQ,2)
sage: gf = R.ideal([x1^3-x2,x2^3-x1-2]).groebner_fan()
sage: gf.ring()
Multivariate Polynomial Ring in x1, x2 over Rational Field
tropical_basis(check=True, verbose=False)
Return a tropical basis for the tropical curve associated to this ideal.
INPUT:
• check - bool (default: True); if True raises a ValueError exception if this ideal does not define a tropical curve (i.e., the condition that R/I has dimension equal to 1 + the dimension of the homogeneity space is not satisfied).
EXAMPLES:
sage: R.<x,y,z> = PolynomialRing(QQ,3, order='lex')
sage: G = R.ideal([y^3-3*x^2, z^3-x-y-2*y^3+2*x^2]).groebner_fan()
sage: G
Groebner fan of the ideal:
Ideal (-3*x^2 + y^3, 2*x^2 - x - 2*y^3 - y + z^3) of Multivariate Polynomial Ring in x, y, z over Rational Field
sage: G.tropical_basis()
[-3*x^2 + y^3, 2*x^2 - x - 2*y^3 - y + z^3, 3/4*x + y^3 + 3/4*y - 3/4*z^3]
tropical_intersection(parameters=, []symmetry_generators=, []*args, **kwds)
Returns information about the tropical intersection of the polynomials defining the ideal. This is the common refinement of the outward-pointing normal fans of the Newton polytopes of the generators of the ideal. Note that some people use the inward-pointing normal fans.
INPUT:
• parameters (optional) - a list of variables to be considered as parameters
• symmetry_generators (optional) - generators of the symmetry group
OUTPUT: a TropicalPrevariety object
EXAMPLES:
sage: R.<x,y,z> = PolynomialRing(QQ,3)
sage: I = R.ideal(x*z + 6*y*z - z^2, x*y + 6*x*z + y*z - z^2, y^2 + x*z + y*z)
sage: gf = I.groebner_fan()
sage: pf = gf.tropical_intersection()
sage: pf.rays()
[[-2, 1, 1]]
sage: R.<x,y,z> = PolynomialRing(QQ,3)
sage: f1 = x*y*z - 1
sage: f2 = f1*(x^2 + y^2 + z^2)
sage: f3 = f2*(x + y + z - 1)
sage: I = R.ideal([f1,f2,f3])
sage: gf = I.groebner_fan()
sage: pf = gf.tropical_intersection(symmetry_generators = '(1,2,0),(1,0,2)')
sage: pf.rays()
[[-2, 1, 1], [1, -2, 1], [1, 1, -2]]
sage: R.<x,y,z> = QQ[]
sage: I = R.ideal([(x+y+z)^2-1,(x+y+z)-x,(x+y+z)-3])
sage: GF = I.groebner_fan()
sage: TI = GF.tropical_intersection()
sage: TI.rays()
[[-1, 0, 0], [0, -1, -1], [1, 1, 1]]
sage: GF = I.groebner_fan()
sage: TI = GF.tropical_intersection(parameters=[y])
sage: TI.rays()
[[-1, 0, 0]]
weight_vectors()
Returns the weight vectors corresponding to the reduced Groebner bases.
EXAMPLES:
sage: r3.<x,y,z> = PolynomialRing(QQ,3)
sage: g = r3.ideal([x^3+y,y^3-z,z^2-x]).groebner_fan()
sage: g.weight_vectors()
[(3, 7, 1), (5, 1, 2), (7, 1, 4), (5, 1, 4), (1, 1, 1), (1, 4, 8), (1, 4, 10)]
sage: r4.<x,y,z,w> = PolynomialRing(QQ,4)
sage: g4 = r4.ideal([x^3+y,y^3-z,z^2-x,z^3 - w]).groebner_fan()
sage: len(g4.weight_vectors())
23
class sage.rings.polynomial.groebner_fan.InitialForm(cone, rays, initial_forms)
A system of initial forms from a polynomial system. To each form is associated a cone and a list of polynomials (the initial form system itself).
This class is intended for internal use inside of the TropicalPrevariety class.
EXAMPLES:
sage: from sage.rings.polynomial.groebner_fan import InitialForm
sage: R.<x,y> = QQ[]
sage: inform = InitialForm([0], [[-1, 0]], [y^2 - 1, y^2 - 2, y^2 - 3])
sage: inform._cone
[0]
cone()
The cone associated with the initial form system.
EXAMPLES:
sage: R.<x,y> = QQ[]
sage: I = R.ideal([(x+y)^2-1,(x+y)^2-2,(x+y)^2-3])
sage: GF = I.groebner_fan()
sage: PF = GF.tropical_intersection()
sage: pfi0 = PF.initial_form_systems()[0]
sage: pfi0.cone()
[0]
initial_forms()
The initial forms (polynomials).
EXAMPLES:
sage: R.<x,y> = QQ[]
sage: I = R.ideal([(x+y)^2-1,(x+y)^2-2,(x+y)^2-3])
sage: GF = I.groebner_fan()
sage: PF = GF.tropical_intersection()
sage: pfi0 = PF.initial_form_systems()[0]
sage: pfi0.initial_forms()
[y^2 - 1, y^2 - 2, y^2 - 3]
internal_ray()
A ray internal to the cone associated with the initial form system.
EXAMPLES:
sage: R.<x,y> = QQ[]
sage: I = R.ideal([(x+y)^2-1,(x+y)^2-2,(x+y)^2-3])
sage: GF = I.groebner_fan()
sage: PF = GF.tropical_intersection()
sage: pfi0 = PF.initial_form_systems()[0]
sage: pfi0.internal_ray()
(-1, 0)
rays()
The rays of the cone associated with the initial form system.
EXAMPLES:
sage: R.<x,y> = QQ[]
sage: I = R.ideal([(x+y)^2-1,(x+y)^2-2,(x+y)^2-3])
sage: GF = I.groebner_fan()
sage: PF = GF.tropical_intersection()
sage: pfi0 = PF.initial_form_systems()[0]
sage: pfi0.rays()
[[-1, 0]]
class sage.rings.polynomial.groebner_fan.PolyhedralCone(gfan_polyhedral_cone, ring=Rational Field)
Converts polymake/gfan data on a polyhedral cone into a sage class. Currently (18-03-2008) needs a lot of work.
EXAMPLES:
sage: R3.<x,y,z> = PolynomialRing(QQ,3)
sage: gf = R3.ideal([x^8-y^4,y^4-z^2,z^2-2]).groebner_fan()
sage: a = gf[0].groebner_cone()
sage: a.facets()
[[0, 0, 1], [0, 1, 0], [1, 0, 0]]
ambient_dim()
Returns the ambient dimension of the Groebner cone.
EXAMPLES:
sage: R3.<x,y,z> = PolynomialRing(QQ,3)
sage: gf = R3.ideal([x^8-y^4,y^4-z^2,z^2-2]).groebner_fan()
sage: a = gf[0].groebner_cone()
sage: a.ambient_dim()
3
dim()
Returns the dimension of the Groebner cone.
EXAMPLES:
sage: R3.<x,y,z> = PolynomialRing(QQ,3)
sage: gf = R3.ideal([x^8-y^4,y^4-z^2,z^2-2]).groebner_fan()
sage: a = gf[0].groebner_cone()
sage: a.dim()
3
facets()
Returns the inward facet normals of the Groebner cone.
EXAMPLES:
sage: R3.<x,y,z> = PolynomialRing(QQ,3)
sage: gf = R3.ideal([x^8-y^4,y^4-z^2,z^2-2]).groebner_fan()
sage: a = gf[0].groebner_cone()
sage: a.facets()
[[0, 0, 1], [0, 1, 0], [1, 0, 0]]
lineality_dim()
Returns the lineality dimension of the Groebner cone. This is just the difference between the ambient dimension and the dimension of the cone.
EXAMPLES:
sage: R3.<x,y,z> = PolynomialRing(QQ,3)
sage: gf = R3.ideal([x^8-y^4,y^4-z^2,z^2-2]).groebner_fan()
sage: a = gf[0].groebner_cone()
sage: a.lineality_dim()
0
relative_interior_point()
Returns a point in the relative interior of the Groebner cone.
EXAMPLES:
sage: R3.<x,y,z> = PolynomialRing(QQ,3)
sage: gf = R3.ideal([x^8-y^4,y^4-z^2,z^2-2]).groebner_fan()
sage: a = gf[0].groebner_cone()
sage: a.relative_interior_point()
[1, 1, 1]
class sage.rings.polynomial.groebner_fan.PolyhedralFan(gfan_polyhedral_fan, parameter_indices=[])
Converts polymake/gfan data on a polyhedral fan into a sage class.
INPUT:
• gfan_polyhedral_fan - output from gfan of a polyhedral fan.
EXAMPLES:
sage: R.<x,y,z> = PolynomialRing(QQ,3)
sage: i2 = ideal(x*z + 6*y*z - z^2, x*y + 6*x*z + y*z - z^2, y^2 + x*z + y*z)
sage: gf2 = i2.groebner_fan(verbose = False)
sage: pf = gf2.polyhedralfan()
sage: pf.rays()
[[-1, 0, 1], [-1, 1, 0], [1, -2, 1], [1, 1, -2], [2, -1, -1]]
ambient_dim()
Returns the ambient dimension of the Groebner fan.
EXAMPLES:
sage: R3.<x,y,z> = PolynomialRing(QQ,3)
sage: gf = R3.ideal([x^8-y^4,y^4-z^2,z^2-2]).groebner_fan()
sage: a = gf.polyhedralfan()
sage: a.ambient_dim()
3
cones()
A dictionary of cones in which the keys are the cone dimensions. For each dimension, the value is a list of the cones, where each element consists of a list of ray indices.
EXAMPLES:
sage: R.<x,y,z> = QQ[]
sage: f = 1+x+y+x*y
sage: I = R.ideal([f+z*f, 2*f+z*f, 3*f+z^2*f])
sage: GF = I.groebner_fan()
sage: PF = GF.tropical_intersection()
sage: PF.cones()
{1: [[0], [1], [2], [3], [4], [5]], 2: [[0, 1], [0, 2], [0, 3], [0, 4], [1, 2], [1, 3], [2, 4], [3, 4], [1, 5], [2, 5], [3, 5], [4, 5]]}
dim()
Returns the dimension of the Groebner fan.
EXAMPLES:
sage: R3.<x,y,z> = PolynomialRing(QQ,3)
sage: gf = R3.ideal([x^8-y^4,y^4-z^2,z^2-2]).groebner_fan()
sage: a = gf.polyhedralfan()
sage: a.dim()
3
f_vector()
The f-vector of the fan.
EXAMPLES:
sage: R.<x,y,z> = QQ[]
sage: f = 1+x+y+x*y
sage: I = R.ideal([f+z*f, 2*f+z*f, 3*f+z^2*f])
sage: GF = I.groebner_fan()
sage: PF = GF.tropical_intersection()
sage: PF.f_vector()
[1, 6, 12]
is_simplicial()
Whether the fan is simplicial or not.
EXAMPLES:
sage: R.<x,y,z> = QQ[]
sage: f = 1+x+y+x*y
sage: I = R.ideal([f+z*f, 2*f+z*f, 3*f+z^2*f])
sage: GF = I.groebner_fan()
sage: PF = GF.tropical_intersection()
sage: PF.is_simplicial()
True
lineality_dim()
Returns the lineality dimension of the fan. This is the dimension of the largest subspace contained in the fan.
EXAMPLES:
sage: R3.<x,y,z> = PolynomialRing(QQ,3)
sage: gf = R3.ideal([x^8-y^4,y^4-z^2,z^2-2]).groebner_fan()
sage: a = gf.polyhedralfan()
sage: a.lineality_dim()
0
maximal_cones()
A dictionary of the maximal cones in which the keys are the cone dimensions. For each dimension, the value is a list of the maximal cones, where each element consists of a list of ray indices.
EXAMPLES:
sage: R.<x,y,z> = QQ[]
sage: f = 1+x+y+x*y
sage: I = R.ideal([f+z*f, 2*f+z*f, 3*f+z^2*f])
sage: GF = I.groebner_fan()
sage: PF = GF.tropical_intersection()
sage: PF.maximal_cones()
{2: [[0, 1], [0, 2], [0, 3], [0, 4], [1, 2], [1, 3], [2, 4], [3, 4], [1, 5], [2, 5], [3, 5], [4, 5]]}
rays()
A list of rays of the polyhedral fan.
EXAMPLES:
sage: R.<x,y,z> = PolynomialRing(QQ,3)
sage: i2 = ideal(x*z + 6*y*z - z^2, x*y + 6*x*z + y*z - z^2, y^2 + x*z + y*z)
sage: gf2 = i2.groebner_fan(verbose = False)
sage: pf = gf2.polyhedralfan()
sage: pf.rays()
[[-1, 0, 1], [-1, 1, 0], [1, -2, 1], [1, 1, -2], [2, -1, -1]]
to_RationalPolyhedralFan()
Converts to the RationalPolyhedralFan class, which is more actively maintained. While the information in each class is essentially the same, the methods and implementation are different.
EXAMPLES:
sage: R.<x,y,z> = QQ[]
sage: f = 1+x+y+x*y
sage: I = R.ideal([f+z*f, 2*f+z*f, 3*f+z^2*f])
sage: GF = I.groebner_fan()
sage: PF = GF.tropical_intersection()
sage: fan = PF.to_RationalPolyhedralFan()
sage: [tuple(q.facet_normals()) for q in fan]
[(M(0, -1, 0), M(-1, 0, 0)), (M(0, 0, -1), M(-1, 0, 0)), (M(0, 0, 1), M(-1, 0, 0)), (M(0, 1, 0), M(-1, 0, 0)), (M(0, 0, -1), M(0, -1, 0)), (M(0, 0, 1), M(0, -1, 0)), (M(0, 1, 0), M(0, 0, -1)), (M(0, 1, 0), M(0, 0, 1)), (M(1, 0, 0), M(0, -1, 0)), (M(1, 0, 0), M(0, 0, -1)), (M(1, 0, 0), M(0, 0, 1)), (M(1, 0, 0), M(0, 1, 0))]
Here we use the RationalPolyhedralFan’s Gale_transform method on a tropical prevariety.
sage: fan.Gale_transform()
[ 1 0 0 0 0 1 -2]
[ 0 1 0 0 1 0 -2]
[ 0 0 1 1 0 0 -2]
class sage.rings.polynomial.groebner_fan.ReducedGroebnerBasis(groebner_fan, gens, gfan_gens)
A class for representing reduced Groebner bases as produced by gfan.
INPUT:
• groebner_fan - a GroebnerFan object from an ideal
• gens - the generators of the ideal
• gfan_gens - the generators as a gfan string
EXAMPLES:
sage: R.<a,b> = PolynomialRing(QQ,2)
sage: gf = R.ideal([a^2-b^2,b-a-1]).groebner_fan()
sage: from sage.rings.polynomial.groebner_fan import ReducedGroebnerBasis
sage: ReducedGroebnerBasis(gf,gf[0],gf[0]._gfan_gens())
[b - 1/2, a + 1/2]
groebner_cone(restrict=False)
Return defining inequalities for the full-dimensional Groebner cone associated to this marked minimal reduced Groebner basis.
INPUT:
• restrict - bool (default: False); if True, add an inequality for each coordinate, so that the cone is restricted to the positive orthant.
OUTPUT: tuple of integer vectors
EXAMPLES:
sage: R.<x,y> = PolynomialRing(QQ,2)
sage: G = R.ideal([y^3 - x^2, y^2 - 13*x]).groebner_fan()
sage: poly_cone = G[1].groebner_cone()
sage: poly_cone.facets()
[[-1, 2], [1, -1]]
sage: [g.groebner_cone().facets() for g in G]
[[[0, 1], [1, -2]], [[-1, 2], [1, -1]], [[-1, 1], [1, 0]]]
sage: G[1].groebner_cone(restrict=True).facets()
[[-1, 2], [1, -1]]
ideal()
Return the ideal generated by this basis.
EXAMPLES:
sage: R.<x,y,z> = PolynomialRing(QQ,3)
sage: G = R.ideal([x - z^3, y^2 - 13*x]).groebner_fan()
sage: G[0].ideal()
Ideal (-13*z^3 + y^2, -z^3 + x) of Multivariate Polynomial Ring in x, y, z over Rational Field
interactive(latex=False, flippable=False, wall=False, inequalities=False, weight=False)
Do an interactive walk of the Groebner fan starting at this reduced Groebner basis.
EXAMPLES:
sage: R.<x,y> = PolynomialRing(QQ,2)
sage: G = R.ideal([y^3 - x^2, y^2 - 13*x]).groebner_fan()
sage: G[0].interactive() # not tested
Initializing gfan interactive mode
*********************************************
*********************************************
....
class sage.rings.polynomial.groebner_fan.TropicalPrevariety(gfan_polyhedral_fan, polynomial_system, poly_ring, parameters=[])
This class is a subclass of the PolyhedralFan class, with some additional methods for tropical prevarieties.
INPUT:
• gfan_polyhedral_fan - output from gfan of a polyhedral fan.
• polynomial_system - a list of polynomials
• poly_ring - the polynomial ring of the list of polynomials
• parameters (optional) - a list of variables to be considered as parameters
EXAMPLES:
sage: R.<x,y,z> = QQ[]
sage: I = R.ideal([(x+y+z)^2-1,(x+y+z)-x,(x+y+z)-3])
sage: GF = I.groebner_fan()
sage: TI = GF.tropical_intersection()
sage: TI._polynomial_system
[x^2 + 2*x*y + y^2 + 2*x*z + 2*y*z + z^2 - 1, y + z, x + y + z - 3]
initial_form_systems()
Returns a list of systems of initial forms for each cone in the tropical prevariety.
EXAMPLES:
sage: R.<x,y> = QQ[]
sage: I = R.ideal([(x+y)^2-1,(x+y)^2-2,(x+y)^2-3])
sage: GF = I.groebner_fan()
sage: PF = GF.tropical_intersection()
sage: pfi = PF.initial_form_systems()
sage: for q in pfi:
... print q.initial_forms()
[y^2 - 1, y^2 - 2, y^2 - 3]
[x^2 - 1, x^2 - 2, x^2 - 3]
[x^2 + 2*x*y + y^2, x^2 + 2*x*y + y^2, x^2 + 2*x*y + y^2]
sage.rings.polynomial.groebner_fan.ideal_to_gfan_format(input_ring, polys)
Return the ideal in gfan’s notation.
EXAMPLES:
sage: R.<x,y,z> = PolynomialRing(QQ,3)
sage: polys = [x^2*y - z, y^2*z - x, z^2*x - y]
sage: from sage.rings.polynomial.groebner_fan import ideal_to_gfan_format
sage: ideal_to_gfan_format(R, polys)
'Q[x, y, z]{x^2*y-z,y^2*z-x,x*z^2-y}'
sage.rings.polynomial.groebner_fan.max_degree(list_of_polys)
Computes the maximum degree of a list of polynomials
EXAMPLES:
sage: from sage.rings.polynomial.groebner_fan import max_degree
sage: R.<x,y> = PolynomialRing(QQ,2)
sage: p_list = [x^2-y,x*y^10-x]
sage: max_degree(p_list)
11.0
sage.rings.polynomial.groebner_fan.prefix_check(str_list)
Checks if any strings in a list are prefixes of another string in the list.
EXAMPLES:
sage: from sage.rings.polynomial.groebner_fan import prefix_check
sage: prefix_check(['z1','z1z1'])
False
sage: prefix_check(['z1','zz1'])
True
sage.rings.polynomial.groebner_fan.ring_to_gfan_format(input_ring)
Converts a ring to gfan’s format.
EXAMPLES:
sage: R.<w,x,y,z> = QQ[]
sage: from sage.rings.polynomial.groebner_fan import ring_to_gfan_format
sage: ring_to_gfan_format(R)
'Q[w, x, y, z]'
sage: R2.<x,y> = GF(2)[]
sage: ring_to_gfan_format(R2)
'Z/2Z[x, y]'
sage.rings.polynomial.groebner_fan.verts_for_normal(normal, poly)
Returns the exponents of the vertices of a newton polytope that make up the supporting hyperplane for the given outward normal.
EXAMPLES:
sage: from sage.rings.polynomial.groebner_fan import verts_for_normal
sage: R.<x,y,z> = PolynomialRing(QQ,3)
sage: f1 = x*y*z - 1
sage: f2 = f1*(x^2 + y^2 + 1)
sage: verts_for_normal([1,1,1],f2)
[(3, 1, 1), (1, 3, 1)]
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Lattice and reflexive polytopes | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.41027605533599854, "perplexity": 6376.937446939823}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-11/segments/1424936463420.52/warc/CC-MAIN-20150226074103-00004-ip-10-28-5-156.ec2.internal.warc.gz"} |
https://cs.stackexchange.com/questions/97333/how-to-know-if-a-code-is-huffman-or-not-without-having-the-probability-of-each-c/97334 | # How to know if a code is Huffman or not without having the probability of each codeword?
I am new to Huffman coding and I find myself facing a lot of confusion as to how to determine if a code is Huffman or not without having the probabilities associated to each codeword. I know one way is look at whether or not the code is prefix. If not, then it's not a Huffman code. If yes, then we need to check if it gives the shortest possible length, but we don't know the probabilities. How do we ensure the code guarantees the shortest possible length in such case? To illustrate my question, let us look at the following two examples:
### Example 1: $\{00,01,10,110\}$
The code is a prefix code, but is the length minimal? I mean it's a bit unusual for me to see Huffman code for $4$ symbols that does not have one-bit codeword for one of its symbol (the symbol with highest probability), but them I thought maybe the first three symbols are equally probable. As such, I tried to find the Huffman code for $\{0.33,0.33,0.33,0.01\}$ and got $\{00,01,10,11\}$ with different orders (depending on the usage of $0,1$ or $1,0$ in the tree). This led me to thinking that the code under investigation might not be Huffman, yet I am still not sure.
### Example 2: $\{01, 10\}$
Again another unusual prefix code as the obvious choice (and the one with minimal length) for two symbols would be $\{0, 1\}$. But could it be the case that $\{01, 10\}$ can possibly give a minimal length? I can not see any possible probabilities in which this is the case, thus I believe this is not a Huffman code.
Am I on the right track? Does there exist an actual method to check whether or nor a code is Huffman without having the probabilities?
• In example 2, you can replace 01 with 0 and get a prefix code with shorter average length, and you can replace 10 with 1 as well. – gnasher729 Sep 15 '18 at 12:22
• Not sure why somebody's voted to close this as "not about computer science". Could anybody voting to close for that reason please explain why? – David Richerby Sep 15 '18 at 18:56
## 2 Answers
If you have a Huffman code, and the codes have lengths $l_i$, then the sum over $2^{-l_i}$ must be equal to 1. In your case, that sum is 1/4 + 1/4 + 1/4 + 1/8 = 7/8 < 1, therefore not a Huffman code. You can replace the code 110 with 11.
(I am quite sure you can prove that for any prefix code, the sum is ≤ 1. And I'm quite sure you can prove that if the sum is less than 1, then there is some bit that you can remove from some code with the code remaining a prefix code, and since there is a finite number of bits to remove, the sum must become 1 eventually).
• This is such a powerful result! Can I have a source stating this? I know about Kraft's inequality but did not know Huffman codes satisfy it with strict equality. – Lod Sep 14 '18 at 21:34
• @Lod look at the process of assigning codes to nodes. it ensures that total codespace is always 1 – Bulat Sep 14 '18 at 21:37
• @Bulat True, but a priori it might be possible that there are Huffman codes that are never generated by some algorithm. – gnasher729 Sep 15 '18 at 12:20
• @gnasher729 Huffman algorithm is an algorithm that finds optimal encoding with concrete algorithm. Prefix codes aren't necessary Huffman ones. The question is correct with terminology ("how to determine if a code is Huffman or not") and your answer is partially correct. I will edit it. – Bulat Sep 15 '18 at 12:30
• I don't care about "Huffman algorithm". All I care about is the codes. A Huffman code for a given set of probabilities is any prefix-code that minimises the expected code length. And a Huffman code is any code that is a Huffman code for some set of probabilities. – gnasher729 Sep 15 '18 at 22:34
When a frequency tree is built for a message upon its characters, the leaf nodes of the tree are the characters composing the message with their frequency and internal nodes just have a frequency sum of all its descendents.
The characteristic property of frequency trees for Huffman encoding is that, all internal nodes have exactly two children.
For your example 1, $\{00,01,10,110\}$, the frequency tree would be something like this (forgive me for how the tree looks like. Subtrees are denoted by + and the first subtree is the left subtree and the second is the right subtree):
(root)
+ (0)
| + (0) (leaf)
| + (1) (leaf)
+ (1)
+ (0) (leaf)
+ (1)
+ (0) (leaf)
The subtree $\{root,1,1\}$ has one child, not two. Hence, such a prefix code can not be a Huffman encoding for any message. Similarly for example two, subtrees $\{root,0\}$ and $\{root,1\}$ have exactly one child. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6824768781661987, "perplexity": 365.12961048125896}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-47/segments/1573496668534.60/warc/CC-MAIN-20191114182304-20191114210304-00138.warc.gz"} |
https://www.physicsforums.com/threads/forgotten-linear-algebra.224823/ | # Forgotten' linear algebra
1. Mar 28, 2008
### jdstokes
Hi all,
I learned this stuff years ago and wasn't brilliant at it even then so I think a refresher is in order.
Suppose I have n distinct homogeneous equations in n unknowns. I want to find the solution so I write down the matrix of coefficients multiplying my vector of variables as follows
$A \mathbf{x} =\mathbf{0}$.
Now, we don't want $\deta A \neq 0$ to happen otherwise the columns of A are linearly independent so the only solution to $A \mathbf{x} = \mathbf{C}_1 x_1 + \cdots \mathbf{C}_n x_n = \mathbf{0}$ is $\mathbf{0}$.
Now how do we actually solve this for $\mathbf{x}$, do we just do Gaussian elimination followed by back-substitution? Is the solution unique in this case?
Now suppose the system is inhomogeneous
$A\mathbf{x} = \mathbf{b}$ where $\mathbf{b}\neq 0$. In this case we actually want $\det A \neq 0$ because then we can instantly write down the unique solution
$\mathbf{x} = A^{-1}\mathbf{b}$.
Have I gotten the solution to square systems about right? If yes, I'll try to figure out the non-square case.
2. Mar 28, 2008
### slider142
If the null space of A is not empty, then it is a subspace, so the solution is an entire subspace of the space you're working with, not just a single vector. The subspace containing only the zero vector is the only degenerate subspace that does consist of a single vector, and it is always in the null space.
Yep, that's right.
Last edited: Mar 28, 2008
3. Mar 28, 2008
### transgalactic
i suggest that after you write your matrix
just make a row reduction
and you are not supposed to write a column of zeros in the end
the last column depends on the last number after the "=" sign
4. Mar 28, 2008
### Peeter
You can also solve systems of equations of this form with the wedge product (wedging the column vectors). I'd put an example of this in the wiki Geometric Algebra page a while back when I started learning the subject:
http://en.wikipedia.org/wiki/Geomet...rally_expressed_in_terms_of_the_wedge_product.
Looking at the example now, I don't think it's the greatest. It should also probably be in a wedge product page instead of GA ... but that was the context that I learned about it first (I chose to use the mostly empty wiki page to dump down my initial notes on the subject as I started learning it;) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8674826622009277, "perplexity": 436.0464233873669}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-04/segments/1484560284429.99/warc/CC-MAIN-20170116095124-00385-ip-10-171-10-70.ec2.internal.warc.gz"} |
https://www.physicsforums.com/threads/please-help-arrow-shot-in-sky-question.60109/ | 1. Jan 17, 2005
### mrd59
Ok, I'm trying to help my son with this test question he got wrong. He is in a basic high school physics class and I have virtually no experience with physics. The book and classroom handouts have nothing that completely explains this question. Any help and explaination would be most wonderful!
An arrow is shot straight up into the air and then falls back down to the ground. On the way up , the arrow could be described as......
A) Positive inertia, positive velocity, positive acceleration and positive momentum. (he marked this and got it wrong)
B)Negative inertia, positive velocity, positive acceleration and negative momentum.
C) positive inertia, negative velocity, negative acceleration and positive momentum
D) Positive inertia, positive velocity, negative acceleration and positive momentum. (we think this might be the correct answer but are not sure why)
:surprised
2. Jan 17, 2005
### ek
Negative acceleration.
Gravity is slowing the arrow down, if it was positive acceleration the arrow would go flying off into space.
3. Jan 17, 2005
### chroot
Staff Emeritus
Is this the entire question?
This question actually has no answer as stated, because it fails to make clear its assumptions. Velocity cannot be said to be positive or negative without first defining which direction should be considered positive! Acceleration suffers the same problem; you must first define the directions. People often consider gravity to be a negative acceleration, but this is just a convention. You could just as well consider it a positive acceleration.
Besides, the terms "positive inertia" and "negative inertia" mean nothing at all. Perhaps the teacher meant kinetic energy?
If this is the entire problem as given, the teacher should really be ripped to shreds. If I were you, I'd be making a phone call.
- Warren
4. Jan 17, 2005
### ek
It's just grade 10 or 11 physics. I don't think there's a need to over complicate things for students. Assumptions are made for the ease of the students I'm guessing. That inertia thing though, I was thinking wtf too.
5. Jan 17, 2005
### chroot
Staff Emeritus
A problem that is not completely specified does not have a completely specified answer, no matter what "easing" is done. If the teacher told the class that "upwards velocities are always positive in my class," then so be it, but we here on physicsforums.com do not have access to that information. We cannot answer it.
- Warren
6. Jan 17, 2005
### mrd59
Yes this is the entire question. He gets some extra points for correcting his test questions and explaining why the wrong answers were wrong and the correct answer is correct. Of course the problem with that is the teacher will not help by telling you which one is the correct answer. All we have are some very sketchy handouts from class and a Conceptual physics book. Most of test questions have taken us a long time to help him figure out (post test) even with these resources. It seems to be a vicious circle. Material is not explained, test questions do not come from the book or handouts, student fails, teacher says find the right answer, but that is hard if you don't know it (which is why you failed), and resources are minimal. A parents' (and students') nightmare!
Last edited: Jan 17, 2005
7. Jan 17, 2005
### Curious3141
As chroot said, the statement of this question is flawed. Although, one can infer the convention from the fact that 3 of the quantities should be signed one way and one the other way meaning there's only one choice that fits. Nevertheless, feedback should be given to the teacher.
I've had bitter experience with teachers who misinform, insist they're right when they're wrong, and then sneakily correct themselves later without fanfare or even acknowledgement.
For the sake of your son and the rest in his class make sure the teacher knows why this question is incomplete. You can always ask the teacher to come here to get chastised. :tongue2:
8. Jan 17, 2005
### chroot
Staff Emeritus
I fondly remember a ninth-grade chemistry teacher spending a half an hour of class time trying to convince me that a milliliter of any substance weighs one gram.
- Warren
9. Jan 17, 2005
### dextercioby
We wouldn't be that lucky... :tongue2:
To the OP:My advice is to start l'exposeé with the words:
"I chose the Oy axis pointing upwards".
Then the answer will be correct and the idiot would have nothing to say...
Daniel.
10. Jan 17, 2005
### mrd59
Thanks to all of you! My daughter is a physics major in college but she's back at school now so not around to help. I might be posting quite often if this class continues to go in this direction!
-m
11. Jan 17, 2005
### Integral
Staff Emeritus
I would bet that in class the teacher had a standard set of definitions for the coordinate system. Clearly he expected his default definitions to be known and understood by the students. We are not privy to such definitions. Your son needs to examine, notes etc. to gain an understanding of these unstated but implied definitions. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8075973987579346, "perplexity": 1244.9373442286064}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-04/segments/1484560279224.13/warc/CC-MAIN-20170116095119-00155-ip-10-171-10-70.ec2.internal.warc.gz"} |
https://brilliant.org/problems/complex-number-1/ | # Complex number 1!
Algebra Level 5
If $$x = 2+5i$$ and $$\large 2(\frac{1}{1!9!} +\frac{1}{3!7!}) + \frac{1}{5!5!} = \frac{2^a}{b!}$$ , then the value of $$(x^3 -5x^2 +33x -19)$$ is equal to
×
Problem Loading...
Note Loading...
Set Loading... | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9669448137283325, "perplexity": 3543.4484921930098}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257645775.16/warc/CC-MAIN-20180318130245-20180318150245-00796.warc.gz"} |
https://aas.org/archives/BAAS/v26n2/aas184/abs/S2907.html | A New Mechanism for Excitation of the [N II] Temperature Diagnostic Emission Lines at 6548 \AA\ and 6584 \AA
Session 29 -- General Interstellar Medium
Display presentation, Tuesday, 31, 1994, 9:20-6:30
## [29.07] A New Mechanism for Excitation of the [N II] Temperature Diagnostic Emission Lines at 6548 \AA\ and 6584 \AA
Todd M. Tripp, John S. Gallagher, and Alan Watson (Washburn Observatory, U. Wisconsin)
This paper discusses the possibility that the intensities of the [N II] emission lines at 6548 and 6584 \AA\ are boosted, in a variety of astrophysical nebulae, by the $(2s^{2}2p^{2}) \ ^{1}D_{2}$ --- $(2s^{2}2p3s) \ ^{3}P^{o}_{1}$ transition at 748 \AA. According to theoretical calculations by Fawcett and experimental measurement of the branching ratio, this intersystem ($\Delta S \neq$ 0) transition is as fast as a typical electric dipole allowed transition. The $(2s^{2}2p3s) \ ^{3}P^{o}_{1}$ level is directly populated by a resonance transition from the $(2s^{2}2p^{2}) \ ^{3}P$ ground state, and one out of three electrons that enter the $(2s^{2}2p3s) \ ^{3}P^{o}_{1}$ level will spontaneously decay through the 748 \AA \ transition. Since the 748 \AA\ transition deposits electrons in the $(2s^{2}2p^{2}) \ ^{1}D_{2}$ level from which the [N II] $\lambda \lambda$6548,6584 emissions originate, this remarkably strong intersystem transition will increase the intensities of the famous [N II] temperature diagnostic emission lines if significant excitation of the $(2s^{2}2p3s) \ ^{3}P^{o}_{1}$ level occurs. We discuss the circumstances in which the $(3s) \ ^{3}P^{o}_{1}$ upper level could be significantly populated by photoexcitation, collisional excitation, or recombination. We point out that detection of recombination lines that feed the $(3s) \ ^{3}P^{o}_{1}$ level provides direct evidence that this process is important in nova shells. We also discuss the possible importance of this process in the production of anomalously large [N II]/H$\alpha$ ratios in cooling flow emission line filaments and starburst galaxy superwinds. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9711276292800903, "perplexity": 3203.297847363753}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-40/segments/1474738660467.49/warc/CC-MAIN-20160924173740-00070-ip-10-143-35-109.ec2.internal.warc.gz"} |
https://newcleckitdominie.wordpress.com/2012/04/22/some-functions-are-less-equal-than-others/ | ## Some functions are less equal than others
Further evidence, among the piles of assignments I’ve been marking this week, for the suggestion that inequalities can reveal a lot about the depth of students’ understanding:
$f(x) \leq g(x) \quad \iff \quad \dfrac{\mathrm{d}f}{\mathrm{d}x} \leq \dfrac{\mathrm{d}g}{\mathrm{d}x}.$
Presumably this is just the old fallacy of treating $\leq$ as an equals sign with a fancy haircut, but I recommend it to anyone faced with a tricky analysis proof to complete. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 2, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4179783761501312, "perplexity": 1359.795368720773}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-26/segments/1498128320545.67/warc/CC-MAIN-20170625170634-20170625190634-00192.warc.gz"} |
https://www.nature.com/articles/s41612-019-0096-2 | Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.
# Urban warming and future air-conditioning use in an Asian megacity: importance of positive feedback
## Abstract
The impact of feedback between urban warming and air-conditioning (AC) use on temperatures in future urban climates is explored in this study. Pseudo-global warming projections are dynamically downscaled to 1 km using a regional climate model (RCM) coupled to urban canopy and building energy models for current and six future global warming (ΔTGW) climates based on IPCC RCP8.5. Anthropogenic heat emissions from AC use is projected to increase almost linearly with ΔTGW, causing additional urban warming. This feedback on urban warming reaches 20% of ΔTGW in residential areas. This further uncertainty in future projections is comparable in size to that associated with: a selection of emission scenarios, RCMs, and urban planning scenarios. Thus this feedback should not be neglected in future urban climate projections, especially in hot cities with large AC use. The impact of the feedback during the July 2018 Japanese heat waves is calculated to be 0.11 °C.
## Introduction
With the global proportion of people living in cities expected to exceed two-thirds by 2050,1 the urban climate affects many aspects of human life, including energy demand, health and the economy. Therefore, urban climate projections that include extreme weather events, such as heat waves from climate change, are of interest, given the potentially wide range of social and scientific impacts on human activities. These projections are also important when producing strategies to mitigate urban heat and for adapting to urban climate change. For example, given that US urban temperatures are predicted to increase by 1–2 °C due to climate change, energy demand is predicted to increase by 5–25%. Therefore, effective adaptation strategies that include measures to cool the urban climate and built environment that do not result in further emissions of heat or greenhouse gases (GHGs) will need to be produced and assessed.2
Of the two main methods to obtain fine horizontal resolution projections of climate, the dynamical (rather than statistical) downscaling is used here. Several previous dynamical downscaling studies of future urban climate have used regional climate models (RCMs) with a coupled urban canopy model (UCM) (hereafter RCM/UCM). For example, Kusaka et al.3 predicted the 2070s summertime climate for three Japanese megacities using the Weather Research and Forecasting (WRF) model4 with the single-layer UCM,5,6 assuming pseudo-global warming (PGW),7,8 at a 3-km resolution. This future climate projection (dynamical downscaling) method uses reanalysis data with the climatic change component from global climate models (GCMs; see ‘Methods’ section). Similar methods have been used for cities in Asia,9,10,11 Europe,12,13 North America14,15 and Oceania.16 In these RCM/UCM studies, anthropogenic heat (QF) is an important term in the urban surface heat balance but is assumed to have a constant diurnal pattern (e.g. Fig. 3 of Kusaka et al.17). Thus QF impact on future urban temperatures is kept the same as current climate if all other factors (e.g. urban structure and human activities) do not change. This assumption may be reasonable in cities with little air-conditioning (AC) use (e.g. northern European cities); however, where AC use is already common (e.g. Asian cities), it may not.
If cities experience positive feedback from interactions between urban warming and AC use,18,19,20,21 this assumption would not hold. When air temperatures increase, energy consumption associated with AC use surges (Fig. 1a, Path 1) (i.e. increase in QF from AC use (QF, AC)). In turn, the energy released outdoors will enhance urban warming (Fig. 1a, Path 2).22 Using a simple one-dimensional mixing-layer model, Ohashi et al.23 estimated the increase in summertime air temperature from AC waste heat in Osaka City to be +0.36 to +0.72 °C. Previous studies focus on only one side of this process. Most consider impacts of urban warming on energy consumption (Fig. 1a, Path 1).24,25,26,27 Effects of QF on urban temperature (Fig. 1a, Path 2) have been studied with limited-area models.28,29,30,31,32,33 However, the amount of ‘additional warming’ from urban warming–AC feedback has yet to be assessed. Hence, the impact of this feedback process on future urban climate remains unknown.
In this study, we define the temperature difference caused by AC use as δTAC (Fig. 1b, orange):
$$\delta T_{{\mathrm{AC}}} = \delta T_{{\mathrm{AC}} \ne {\mathrm{FB}}} + \delta T_{{\mathrm{AC}} \to {\mathrm{FB}}}$$
(1)
where δTAC ≠ FB is the temperature difference caused by AC use but without AC feedback (Fig. 1b purple, without Path 2 Fig. 1a [no-QF,AC simulation], see ‘Methods’ [Model settings]). The ‘additional temperature difference’ caused by the feedback process is δTAC → FB (Fig. 1b, green, with Path 2 Fig. 1a). In this study, we use model simulations to determine the different components (Fig. 1b and ‘Methods’ provide more details).
The Salamanca et al.’s22 WRF/BEP+BEM (building effect parameterisation and building energy model)34,35,36 simulations, with and without QF,AC release, allows δTAC to be estimated (Fig. 1b, reference (R) Salamanca et al.,22 RS14). The 10-day Phoenix heat wave study obtained an extreme δTAC of 1.0 °C at night. However, as they did not separate δTAC, δTAC → FB remains unknown. Given that δTAC → FB may enhance electricity consumption (hereafter δECAC → FB), we do not have a basis for understanding these changes with climate change (Fig. 1b, red).
With increases in both global temperatures37 and AC demand,38 it is important to explore this positive feedback phenomenon and evaluate its impact on the urban climate. Projected increases in AC demand and urban expansion may increase the feedback effect enhancing future projections uncertainties, whereas improved AC performance may offset demand from a warmer ambient environment. These could be as important as other uncertainties, such as the selection of emission scenarios, RCMs, urban planning scenarios and so on. Thus the feedback process consequently affects the impact assessment results and policy decisions associated with the Paris Agreement.39
Direct feedbacks can be calculated from climate projections for cities with AC usage when the RCM/UCM is coupled to a BEM. Electricity demand and summer thermal comfort projections for Nagoya in the 2070s40 used WRF with coupled multi-layer UCM (CM)41 and BEM19 (WRF/CM+BEM42) (Fig. 1b, RT15). Impacts of urban expansion and global warming on future urban temperatures and cooling demand for the Phoenix and Tucson metropolitan areas43 explored with WRF/BEP+BEM (Fig. 1b, RT17) did not assess the ‘additional warming’ from positive feedbacks (δTAC → FB) (Fig. 1b, green) but did determine the amount of urban warming from current and future climate (ΔT) and the future electricity demand. This study addresses:
1. (1)
What is the magnitude of the impact (and associated uncertainty) associated with such a feedback (δTAC → FB and δECAC → FB) on future urban climate (Fig. 1b, green)?
2. (2)
How is δTAC → FB and δECAC → FB changed by climate change (i.e. increase/decrease, linear/nonlinear) (Fig. 1b, red)?
To address these, objectives WRF/BEP+BEM is used (‘Methods’). From the results, we propose a simple parameterisation to account for δTAC → FB and δECAC → FB in urban climate studies. We focus on Japan’s second-largest megacity, Osaka (Fig. 2, Supplementary Fig. 2), as it experiences the warmest summertime mean temperatures in Japan.44 Osaka’s humid climate (normal annual precipitation (1981–2010) is 1279 mm) results in a more significant daytime urban heat island intensity than other dry climate cities.45
## Results
### Changes in QF,AC and urban air temperature (ΔT)
The numerical model (see ‘Methods’) is verified (see Supplementary Note) for wooden detached dwellings, fireproof apartments and commercial and office buildings (hereafter simply office). Given the similarity of the results between the two dwelling types, only the fireproof apartments (hereafter simply residential) results are presented.
The mean QF,AC at 14:00 local time (LT) (i.e. close to a daily maximum of air temperature) in August is larger for office than residential areas for all seven control simulations (hereafter AC → FB) (Fig. 2a–g and ‘Methods’). QF,AC increases from current to future climates (ΔQF,AC) as ΔTGW increases, which is associated with additional AC use (Fig. 2a–g) causing a close to linear increase in both the office (ΔQF,ACTGW = 1.76 W m−2 °C−1) and residential areas (3.32 W m–2 °C–1). When ΔTGW is +3.0 °C, ΔQF,AC is 1.37 (office) to 1.81 (residential) times larger than for current climate conditions (Supplementary Table 1).
The mean August 2 m air temperature (24 h, 11 years) in Osaka is warmer than the surrounding areas in both current and future climates (Fig. 2h–n). The temperature difference between the AC → FB and the no-QF, AC case (AC ≠ FB) simulations increases along with ΔTGW (Fig. 3), indicating that urban heat will increase over time. This is caused by ΔQF,AC with larger differences in the residential than in the office areas.
The differences between simulations with (ΔTAC → FB) and without (ΔTAC ≠ FB) anthropogenic heat fluxes allows the δTAC → FB to be determined (Figs. 1a 2o–t and 3). The δTAC → FB (05:00, 11 August months) and ΔTGW increase and the δTAC → FB in Osaka’s surrounding areas are higher than those of the centre of Osaka in both current and future climates (Fig. 2o–t). The diurnal variation of the δTAC → FB in residential areas (Fig. 3b) has two main features:
1. (1)
δTAC → FB for current and future climates are relatively small during daytime (notably 09:00–18:00) but larger at night (notably 18:00–06:00), with a peak around 05:00; and
2. (2)
δTAC → FB increases gradually as ΔTGW increases (+0.5 °C to +3.0 °C) during the night, indicating that urban warmth will increase overnight.
The relatively small daytime δTAC → FB, despite the relatively large daytime QF,AC, is because of the relatively high daytime mixed layer. As QF,AC is mixed in a large volume, the impact of QF,AC on surface air temperature is reduced. At night, QF,AC is smaller, but the mixed layer height is lower. Similar results in previous work31 support this proposed mechanism.
The relation between ΔTGW and downscaled urban warming (ΔTAC → FB and ΔTAC ≠ FB) has two main features for office areas (Fig. 3d):
1. (1)
δTAC → FB tends to increase linearly with ΔTGW. This increase is from a feedback: ΔTGW modifies ΔQF,AC, contributing to additional urban warming (Fig. 1a, Path 1 → Path 2)
$$\Delta T_{GW} \to \Delta Q_{F,AC} \to {\mathrm{\delta }}T_{AC \to FB}$$
2. (2)
ΔTAC → FB has a linear trend, as does ΔTAC ≠ FB.
This is the first study to estimate the ‘additional’ positive feedback impact on future climate associated with AC. We conclude that ΔTAC → FB has an approximately linear trend (Fig. 3c–f, red). The resulting AC → FB case slope (ΔTAC → FBTGW) is 1.18 °C °C–1 for the office areas. This is larger than for the AC ≠ FB case (1.13 °C °C–1). These results suggest that it is relatively easy to estimate (parameterise) the impact of the feedback.
The two features in the monthly mean (Fig. 3d) are more evident at 05:00 (Fig. 3c) with ΔTAC → FBTGW = 1.29 °C °C–1, which is larger than for case AC ≠ FB (1.17 °C °C–1). At 14:00 feature (1), ΔTAC → FB and ΔTAC ≠ FB are essentially the same, and δTAC → FB does not increase with ΔTGW.
The daily average of normalised δTAC → FB (see ‘Methods’) is roughly constant (3–5%) and not dependent on ΔTGW for the office area (Supplementary Fig. 1a). The average of normalised δTAC → FB at 05:00 increases from 3% (+0.5 °C) to 10% (+3.0 °C) as ΔTGW increases (Supplementary Fig. 1a, Supplementary Table 1).
Results for the residential area are similar to the office area, but feature (1) is more evident, especially at 05:00 (Fig. 3e, f). The ΔTAC → FBTGW (1.38 °C °C–1) is larger than the AC ≠ FB case (1.16 °C °C–1). As AC is used 24 h per day in residential areas, this cumulatively contributes more to warming than in office areas. The daily average of normalised δTAC → FB increases slightly from +0.5 to +3.0 °C, reaching 8% (at +3.0 °C). Thus about 0.25 °C additional urban warming is caused by the feedback when ΔTGW is +3.0 °C in the residential area. The normalised δTAC → FB at 05:00 increases from 8% (at +0.5 °C) to 20% (at +3.0 °C). This means that about 0.6 °C additional urban warming is caused by the feedback when ΔTGW is +3.0 °C (Fig. 3e).
## Discussion
### Importance of the feedback in adapting to future urban climate change
The choice of emission scenario causes uncertainty in projections. For example, the 2070s August mean urban temperatures in Osaka in the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios with the A2 scenario projected 0.3 °C higher than A1b.46 Doan and Kusaka’s11 urban warming projections (current to 2050s) for greater Ho Chi Minh City based on IPCC representative concentration pathway 4.5 (RCP4.5) and RCP8.5 scenarios found different scenarios to cause urban warming differences of 0.5 °C. The feedback uncertainty (~0.25 °C for residential areas when ΔTGW = + 3.0 °C) is comparable to these emission scenario differences of 0.3 and 0.5 °C, respectively (Table 1a). Further uncertainty arises from the RCM choice. Kusaka et al.’s10 August 2050s urban temperature projections in central Tokyo, using WRF and NHRCM (non-hydrostatic model of the Japan Meteorological Agency47), had a 10-year mean temperature increase uncertainty between RCMs of ~0.2 °C (i.e. like the feedback reported here, see Table 1a).
Our work shows δTAC → FB could reach 0.25 °C in residential areas. This is comparable to the 0.3–0.5 °C century−1 estimated global warming in Japan.48 This feedback impact of 0.25 °C in residential areas is comparable to urban planning scenarios (Adachi et al.,49 Kusaka et al.10) for ‘dispersed’ (~0.34 and 0.1 °C, respectively) and ‘compact’ (~0.1 and 0.4 °C, respectively) cities and future urbanisation on temperature of 0.5 °C11 (Table 1a).
The feedback impact is small in the daytime but large nocturnally, increasing with ΔTGW (Fig. 3). The normalised δTAC → FB at 05:00 increases with ΔTGW: 10% in the office areas and 20% in the residential areas, when ΔTGW is +3.0 °C (Supplementary Fig. 1). These results suggest that mitigating the feedback process before the impact becomes large may be an effective strategy to adapt to climate change in cities as the feedback effect could be comparable to those of past global warming, affecting urban planning scenarios. For example (Supplementary Discussion), the feedback uncertainty for a ΔTGW of +2.0 °C is ~10 years (Fig. 4b, Table 1b), if we can stop the feedback technologically (e.g. improved coefficient of performance (COP), geothermal energy use) we could postpone a +2.0 °C world by about 10 years.
### Application: δTAC → FB and δECAC → FB estimates for the recent heat waves in Japan
As shown (‘Results’), ΔTAC → FB and δTAC → FB have near linear trends with ΔTGW. Also δTAC → FB and δECAC → FB are close to linear with ΔTAC → FB. This suggests that to estimate (parameterise) δTAC → FB and δECAC → FB for other future urban climates or for specific events (e.g. heat waves) is straightforward. Table 2 shows gradients (a) of linear regression (y = ax) between ΔTAC → FB (x) and δTAC → FBECAC → FB) (y). Here we estimate the δTAC → FB and δECAC → FB for the recent heat waves of July 2018 and August 2013 in Japan using our proposed linear relations to illustrate an application.
The 2013 summer was the warmest on record for Japan (statistics since 194650), with 41.0 °C recorded in western Japan (Shimanto City). In Osaka City, the August monthly mean (30.0 °C) was 0.99 °C higher than the 11-year mean (2000–2010). July 2018 was one of the hottest Julys in Japan since 1946, with Osaka’s monthly mean temperature (29.5 °C) 1.63 °C higher than the 11-year mean (2000–2010). Therefore, August 2013 and July 2018 roughly correspond to situations when ΔTAC → FB = +1.0 °C and +1.5 °C, respectively. Figure 3a, b shows a diurnal variation of the δTAC → FB for the two heat waves estimated by linear relations (Table 2a). The δTAC → FB for the two heat waves during the night to morning are higher than that for the daytime, especially in the residential areas. The 24-h mean δTAC → FB for July 2018 is 0.11 °C in the residential areas, which is higher than the 0.07 °C of August 2013. Similarly, the 24-h mean δECAC → FB for July 2018 is 0.05 W floor-m−2, which is higher than 0.03 W floor-m−2 of August 2013. Estimates of δTAC → FB and δECAC → FB could be easily assessed for other heat waves and/or future urban climates in hot cities where significant AC use is common.
### Summary
Here a positive feedback from the interaction between urban warming and AC use is identified and quantified. Analysis of simulations for current and six future climate scenarios (global warming: ΔTGW) is undertaken. For the latter, CMIP5 GCMs simulations with the highest IPCC GHG emissions scenario (RCP8.5) were used. The megacity of Osaka is analysed for August when AC use is at its greatest. From this, it is concluded that:
1. (i)
Anthropogenic heat emissions from AC use (QF,AC) are predicted to increase linearly with ΔTGW from current to future climates. Monthly total QF,AC in commercial & office and residential areas are projected to be 1.37 and 1.81 times larger than current climate conditions when ΔTGW is +3.0 °C, respectively;
2. (ii)
This represents a feedback process from current to future climate:
ΔTGW → ΔQF,AC (QF,AC increase) → δTAC → FB (‘additional’ temperature increase from the feedback)
Urban warming calculated when anthropogenic heat fluxes are permitted [case AC → FB (ΔTAC → FB)] is greater than when they are not included [case AC ≠ FB (ΔTAC ≠ FB)]. The difference between these two [ΔTAC → FB − ΔTAC ≠ FB] provides δTAC → FB. This increases almost linearly with ΔTGW suggesting urban temperatures will increase faster than global warming due to the increase of the anthropogenic heating (assuming all other characteristics of the city remain constant) in future climates. The normalised δTAC → FB at 05:00 (LT) has the larger increase with ΔTGW. This reaches 10% of ΔTGW in office areas and 20% in residential area. Thus about 0.3 °C (office) and 0.6 °C (residential) additional urban warming is caused by the feedback when ΔTGW is +3.0 °C. The δTAC → FB is expected to increase EC through a feedback process:
ΔTGW → ΔQF, AC → δTAC → FB → δECAC → FB (‘additional’ EC increase from the feedback).
The EC increase calculated by case AC → FB (ΔECAC → FB) is greater than that calculated by case AC ≠ FB (ΔECAC ≠ FB). The difference between these (ΔECAC → FB − ΔECAC ≠ FB): δECAC → FB increased linearly with ΔTGW;
3. (iii)
Uncertainty introduced by the feedback (δTAC → FB) is comparable to that introduced from selection of emission scenario, RCM and/or urban planning scenario. Thus this feedback should not be neglected in future urban climate projection, especially in hot cities where significant AC use is common; and
4. (iv)
Using linear relations proposed in this study (between ΔTAC → FB and δTAC → FB), the δTAC → FB during recent Japanese heat waves (July 2018 and August 2013) are estimated to be 0.11 and 0.07 °C, respectively. Such an approach can be used to estimate δTAC → FB for other heat waves and/or future urban climates in hot cities where significant AC use is common.
## Methods
To distinguish the difference between current and future climate Δ (e.g. ΔT) is used, and between cases with the same ∆TGW, δ is used (e.g. δT is a temperature difference between AC → FB and AC ≠ FB (explained later) at current climate or a future climate).
First, the impacts of the feedback (δTAC → FB) on future urban climate from global temperature scenarios (hereafter ΔTGW) are evaluated. Second, we explore how δTAC → FB changes in relation to ΔTGW. The urban air temperature and EC calculated by WRF/BEP+BEM were verified using detailed observational data for a year.51
### Description of the numerical model
Previously, WRF/BEP+BEM simulated urban air temperature and EC for April 2013 to March 2014 in Osaka were verified.51 The modified model reproduced current diurnal and horizontal variations of 2 m urban air temperature and EC at a 1-h temporal resolution for 12 electric power substations within Osaka City (about 1 km2 area).
At each time step, QF,AC is calculated for each grid as:19,51
$$Q_{{\mathrm{F},\mathrm{AC}}} = \left( {H_{{\mathrm{out}}} + E_{{\mathrm{out}}}} \right) + {EC} = \frac{{{\mathrm{COP}} + 1}}{{{\mathrm{COP}}}}\left( {H_{{\mathrm{out}}} + E_{{\mathrm{out}}}} \right)$$
(2)
where Hout and Eout are the sensible and latent heat supplied from the AC system for cooling (see section 2.5 of Salamanca et al.35), respectively, and COP is the coefficient of performance. The Hout and Eout are calculated from the total sensible, Hin, and latent, Ein, heat loads per floor.35 The Hin considers four physical processes: (1) solar radiation through the window and the heat exchange between the windows and the indoor air, (2) heat conduction through the walls and heat exchange between the wall, ceiling and pavement and the indoor air, (3) sensible heat exchange through ventilation, and (4) the internal sensible heat generation from equipment and occupants (Fig. 1a). Outdoor weather directly affects the Hin through processes (1–3), and the affected Hin contributes to an increase in QF,AC and EC through the Hout (Fig. 1a Path 1). Here QF,AC is split into sensible heat QF,AC,S and latent heat, QF,AC,L, as commercial and office building areas are considered52
$$Q_{{\mathrm{F},\mathrm{AC},\mathrm{S}}} = 0.722Q_{{\mathrm{F},\mathrm{AC}}}$$
(3)
$$Q_{{\mathrm{F},\mathrm{AC},\mathrm{L}}} = 0.278Q_{{\mathrm{F},\mathrm{AC}}}$$
(4)
The WRF/BEP+ BEM model system assumptions include:51 (1) individual AC units exist (using a simple parameterisation); (2) a constant COP (implications discussed in Supplemental information) occurs; (3) no QF from traffic occurs; and (4) only typical weekdays occur. Therefore, the results of this study are for these conditions (i.e. weekdays).
Although QF from traffic (QF,traffic) is important53,54 in some cities, in Osaka42,52 QF,AC is at least two times larger. As traffic is already common in Asian megacities, while AC demand is dramatically increasing38 (e.g. in Vietnam penetration rates of AC, motorcar and motorbike are 10.8%, 77.4%, and 81.8%, respectively55), QF,AC has the potential to be a big problem in the future (cf. QF,traffic) but will benefit from COP increases. Future studies will consider QF,AC and QF,traffic using models such as WRF/CM+BEM.42 However, the conclusions of this report are not impacted by QF,traffic as it is assumed to be constant and uses the single-layer UCM (SLUCM) with a static QF5,6 profile (traffic and AC) giving parallel results to urban warming without QF emissions (see next section ‘Model settings’).
### Model settings
Here the Advanced Research WRF model (ver. 3.5.1)4 was used with the same model parameters (Supplementary Table 3) and physics as previously described.51 The specific schemes used are: updated Rapid Radiation Transfer Model (RRTMG) short- and long-wave radiation schemes,56 WRF single-moment three-class (WSM3) cloud microphysics scheme,57,58 Mellor–Yamada–Janjic atmospheric boundary-layer scheme,59,60,61 Noah land surface model,62 and BEP+BEM model.34,35,36 As previously indicated, these models can accurately reproduce the diurnal variation and horizontal distribution of summertime surface air temperature and EC due to AC use.51
The model domain (Supplementary Fig. 2a) covers western Japan with 126 x and y grids in both d01 and d02 domains (horizontal resolution 5 and 1 km, respectively, and two-way nesting). As the reanalysis captures the summer synoptic-scale features (high-pressure system) around Japan,63 a larger coarse grid is not needed. The model top is 50 hPa, with 35 vertical sigma levels. The vertical resolution close to the ground (WRF atmospheric first layer height) is nearly 50 m. Therefore, 10 building layers below 50 m (5 m resolution) in BEP/BEM is used, as in previous studies,42,51 due to high model reproducibility for 2 m air temperature and EC in Osaka with the first layer at 50 m. With a mean building height of about 25 m in the office area, 50 m corresponds to the constant flux layer. The innermost domain urban grid classifications are based on the dominant building type, using land use and land cover and topographic data sets from the Geospatial Information Authority of Japan data and Osaka City GIS polygon (building footprint) data, with building use (type), building height and total floor area for each building (Supplementary Fig. 2c, d) grouped into: (i) commercial and business grids (i.e. mainly commercial and office buildings; hereafter C), (ii) residential grids with predominantly fireproof apartments (Rr), and (iii) residential grids with predominately wooden detached dwellings (Rw). The outer and inner domain urban grids outside Osaka City are classified as Rw.
For current climate simulation, initial and boundary conditions are derived from the National Center for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis data64 and merged satellite and in situ global daily sea surface temperature (MGDSST) data.65 For future climate simulations, we also use a modified the NCEP–NCAR and MGDSST as initial and boundary conditions (see details in the next subsection). As previously,3 time integration is conducted from 00:00 UTC July 27 to September 1 (i.e. August with 5 days spin-up) for 11 years 2000–2010 to allow climatological discussion of the simulation results. Other studies integrate for only 1 month, several weeks or days (current and future climate), which is insufficient for climatological discussion in general. In Osaka, August is the hottest month, with more clear skies (cf. June, July and September, rainy season) and the highest EC recorded. These model settings are termed the control simulation (case AC → FB) (Fig. 1b, red arrow) for all climates, including current and six future climates (see next subsection).
The no-QF, AC simulation (case AC ≠ FB) differs from case AC → FB as QF, AC = 0 W m−2 (Fig. 1b, blue arrow); i.e. the [AC ≠ FB] − [AC → FB] difference is caused by QF, AC and it causes the feedback (δTAC → FB). Current climate conditions (August 2000–2010) and six future climates are simulated. Here δTAC → FB is estimated by ΔTAC → FB − ΔTAC ≠ FB (Fig. 1b). In the current climate case, δTAC → FB is 0 °C as we assume there is no long-term climate change (decades) (i.e. no increase in forcing temperature and ΔTAC → FB and ΔTAC ≠ FB are 0 °C). Of course, δTAC → FB may not be 0 °C in the real current climate, but it is difficult to estimate δTAC → FB from current climate only, and our objectives are to clarify δTAC → FB in relation to future urban climate and how δTAC → FB is changed by climate change (see ‘Introduction’). Therefore, here ‘δTAC → FB driven by decades of climate change’ is the focus and is estimated by a time slice experiment, including current climate simulation and six future projections. In a similar way, δECAC → FB is estimated by ΔECAC → FB − ΔECAC ≠ FB. To determine δTAC → FB and δECAC → FB, it is assumed all conditions (e.g. urban structures, human activities and AC system technology) remain constant, except for background climate change. Although AC technology will improve, it is important to know the maximum (potential) impact of the feedback driven by climate change on future urban air temperature. A constant COP scenario is used as the RCP8.5, and Shared Socioeconomic Pathway 3 scenario assumes slow technological change in the energy sector.66,67
We assume that δTAC ≠ FB is constant with ΔTGW; i.e. black dashed arrow (ΔTconst.QF) parallel to the blue arrow (ΔTAC ≠ FB) in Fig. 1b. To confirm this, the impact of QF on surface air temperature (i.e. like δTAC ≠ FB), on future climate, was conducted with simulations using SLUCM, which has a static QF5,6 (includes traffic and AC). Urban warming, when QF in the future was the same as for the current climate (ΔTconst.QF: Fig. 1b, black dashed arrow), paralleled urban warming with a no-QF emitted case, like ΔTAC ≠ FB, although different urban parameterisation was used. A reason why we used SLUCM (not BEP/BEM) to confirm black dashed arrow (ΔTconst.QF)’s gradient (ΔTconst.QFTGW) (and then compared with that of blue arrow (ΔTAC ≠ FB) by BEP/BEM) is that it is quite difficult to calculate the black dashed arrow by the BEP/BEM, because QF, AC at every time step (6 s) in future climates has to be completely same as that of current climate. To confirm the black arrow’s gradient by SLUCM is technically much easier and essentially same as that by the BEP/BEM.
### Climate projections
Six future climates, with background temperature increases (global warming: ΔTGW: +0.5, +1.0, +1.5, +2.0, +2.5, and +3.0 °C) relative to the current climate, are simulated. These are based on the ensemble mean results from four GCMs used in the Climate Model Intercomparison Project (CMIP5)68: CCSM4,69 CESM1 (CAM5),70 GFDL-CM371, and INM-CM4.72 However, the ensemble mean of only three GCMs (CCSM4, CESM1 and GFDL-CM3) is used when ΔTGW > +3.0 °C, as INM-CM4 does not reach +3.0 °C at 2100. The simulations considered the highest IPCC GHG emissions scenario (RCP8.5) (Fig. 4). CESM1 (CAM5) and CCSM4 have good model climate performance index scores73 and summertime synoptic pressure patterns around Japan perform better than other GCMs. GFDL-CM3 and INM-CM4 are selected to cover minimum to maximum uncertainties in GCM projections. By using several GCMs, the uncertainties in the GCM projections (horizontal colour bars, Fig. 4) are incorporated in the RCM. A similar GCMs selection method for future urban climate projection was used by Adachi et al.9
For future projection experiments, climate difference components between current and future are estimated by the four individual GCMs. For example, for ΔTGW = +0.5 °C, it was identified that the August mean surface air temperature difference, averaged spatially around Japan, became nearly +0.5 °C for each GCM. The other climate variables (e.g. geopotential height, horizontal wind and sea surface temperature) are extracted for each GCM for the identified years, and an ensemble mean is calculated for all variables. For ΔTGW = +0.5 °C, the ensemble mean surface air temperature difference component is +0.4725 °C (Supplementary Fig. 3) (i.e. nearly +0.5 °C). The actual ensemble mean surface air temperature differences for ΔTGW = +0.5, +1.0, +1.5, +2.0, +2.5 and +3.0 °C are +0.4725, +0.9550, +1.4750, +1.9650, +2.4450 and +2.8825 °C, respectively (Supplementary Fig. 3). For the six ΔTGW cases, the climate difference for each variable (i.e. wind components, geopotential height and temperature) are added to the NCEP–NCAR and MGDSST data (Supplementary Fig. 3), therefore changing the atmospheric variables such as long-wave radiation. Note, future climate relative humidity is assumed to be the same as the current climate.74,75,76,77,78
The PGW method7,8 was used to create regional climate projections3,10,11,21,79,80,81 and has been previously verified.80,82,83 For example, Kawase et al.82 projected East Asia’s 1960s climate by the PGW method using 1990s reanalysis data and PGW increment, calculated by the climate difference between the 1990s and 1960s. They compared the 1960s projection results with a hindcast simulation for the same period using reanalysis data. They showed that the 1960s projection could reproduce some decadal changes in the rainfall shown within the hindcast simulation, thus indicating that the PGW method could reproduce actual energy balance change using reanalysis, as precipitation is calculated in response to the atmospheric energy balance.
Yoshikane et al.83 compared PGW and direct downscaling from GCM for East Asian future climate projections and found no significant differences in temperature and precipitation (i.e. atmospheric energy balances were similar). Snowfall79,81,84 research, a process strongly influenced by atmospheric energy balance near the surface, and torrential rain85 studies, caused by atmospheric buoyancy near the surface, have also successfully used PGW methods. Therefore, the PGW method is reasonable for use in future projection research. An advantage of using the PGW method is a reduction in GCM climate bias as the method uses modified objective analysis/re-analysis data rather than GCM output.10 A disadvantage is that perturbations in meteorological variables are not considered.86 As Adachi et al.87 show, the perturbation component is equally important as the climatology component for summer precipitation, hence the PGW method is inappropriate for this. However, the perturbations do not affect near-surface air temperatures change (current to future climates) in western Japan, including Osaka during summer.87 Thus the difference in climatology projected by a GCM has a larger influence than the difference in perturbation on the downscaled temperature change and its variability in the climate projections.87 Hence, as the main contributor to the temperatures change was climate change (PGW) component, their results indicate that PGW method is appropriate for our purpose. As we focus on August, a dry period in Japan, surface air temperature is little impacted by precipitation. The PGW method is used as it enabled the study to focus on internal physical (feedback) processes in the RCM and to remove bias from individual GCMs. It also allows for direct comparison with previous PGW studies that report projected urban temperature uncertainties with selections of RCM, GHG emission scenarios and urban planning scenarios (see Table 1 and main text).
### Normalised feedback impact
Three urban land uses are selected for analysis (Supplementary Fig. 2d): commercial and office buildings, fireproof apartments, and wooden detached dwellings. These types of areas were evaluated for surface air temperature and EC model performance.48
To address the question (1), a normalised δTAC → FB (feedback impact) per future climate is determined:
$${\mathrm{Normalised}}\,\delta T_{{\mathrm{AC}} \to {\mathrm{FB}}} = \frac{{\left( {\Delta T_{{\mathrm{AC}} \to {\mathrm{FB}}} - \Delta T_{{\mathrm{AC}} \ne {\mathrm{FB}}}} \right)}}{{\Delta T_{{\mathrm{GW}}}}}$$
(5)
where ΔTAC → FB and ΔTAC ≠ FB are urban warming calculated by the AC → FB and AC ≠ FB, respectively, as explained in Fig. 1.
All times referred to are LT. Japan does not use summertime.
## Data availability
The downscaling data by the WRF are deposited in local storage at AIST. This is available from the corresponding author upon reasonable request. The source code of the WRF and future projection results by four global climate models (CCSM4, CESM1 (CAM5), GFDL-CM3 and INM-CM4) that support findings of this study are available from websites: http://www2.mmm.ucar.edu/wrf/users/ and https://esgf-node.llnl.gov/projects/esgf-llnl/, respectively. The observational data used in this study are available from the website of the Japan Meteorological Agency: https://www.jma.go.jp/jma/index.html.
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## Acknowledgements
This study is supported by JSPS Overseas Research Fellowships and JSPS KAKENHI Grant–in–Aid for Scientific Research (B) Number 16H04441. We thank EPSRC LoHCool (EP/N009797/1). We also thank Dr. Sachiho A. Adachi of RIKEN Advanced Institute for Computational Sciences for helpful advice associated with the selection of GCMs, and Mr. Toshiharu Nagatomo of National Institute of Advanced Industrial Science and Technology (AIST) who helped with some data analyses. The numerical simulations are performed under the ‘Interdisciplinary Computational Science Program’ in the Center for Computational Sciences, University of Tsukuba. The free software package Generic Mapping Tools (GMT) is used to draw the figures.
## Author information
Authors
### Contributions
Y.T., Y.K. and M.H. conceived the study and designed the analyses. S.G. provided an important idea. M.H. prepared the forcing data for regional climate simulations, and Y.T. conducted the simulations and analysis using this forcing data. Y.T. wrote the original manuscript and S.G., Y.K. and M.H. provided comments, feedback and revisions to the manuscript.
### Corresponding author
Correspondence to Yuya Takane.
## Ethics declarations
### Competing interests
The authors declare no competing interests.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Takane, Y., Kikegawa, Y., Hara, M. et al. Urban warming and future air-conditioning use in an Asian megacity: importance of positive feedback. npj Clim Atmos Sci 2, 39 (2019). https://doi.org/10.1038/s41612-019-0096-2
• Accepted:
• Published:
• DOI: https://doi.org/10.1038/s41612-019-0096-2
• ### Urban climate changes during the COVID-19 pandemic: integration of urban-building-energy model with social big data
• Yuya Takane
• Ko Nakajima
• Yukihiro Kikegawa
npj Climate and Atmospheric Science (2022)
• ### Large model structural uncertainty in global projections of urban heat waves
• Zhonghua Zheng
• Lei Zhao
• Keith W. Oleson
Nature Communications (2021) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6857021450996399, "perplexity": 7086.257220502098}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-33/segments/1659882571950.76/warc/CC-MAIN-20220813111851-20220813141851-00537.warc.gz"} |
https://en.wikipedia.org/wiki/Unicity_distance | # Unicity distance
In cryptography, unicity distance is the length of an original ciphertext needed to break the cipher by reducing the number of possible spurious keys to zero in a brute force attack. That is, after trying every possible key, there should be just one decipherment that makes sense, i.e. expected amount of ciphertext needed to determine the key completely, assuming the underlying message has redundancy.[1]
Claude Shannon defined the unicity distance in his 1949 paper "Communication Theory of Secrecy Systems."
Consider an attack on the ciphertext string "WNAIW" encrypted using a Vigenère cipher with a five letter key. Conceivably, this string could be deciphered into any other string — RIVER and WATER are both possibilities for certain keys. This is a general rule of cryptanalysis: with no additional information it is impossible to decode this message.
Of course, even in this case, only a certain number of five letter keys will result in English words. Trying all possible keys we will not only get RIVER and WATER, but SXOOS and KHDOP as well. The number of "working" keys will likely be very much smaller than the set of all possible keys. The problem is knowing which of these "working" keys is the right one; the rest are spurious.
## Relation with key size and possible plaintexts
In general, given particular assumptions about the size of the key and the number of possible messages, there is an average ciphertext length where there is only one key (on average) that will generate a readable message. In the example above we see only upper case English characters, so if we assume that the plaintext has this form, then there are 26 possible letters for each position in the string. Likewise if we assume five-character upper case keys, there are K=265 possible keys, of which the majority will not "work".
A tremendous number of possible messages, N, can be generated using even this limited set of characters: N = 26L, where L is the length of the message. However, only a smaller set of them is readable plaintext due to the rules of the language, perhaps M of them, where M is likely to be very much smaller than N. Moreover, M has a one-to-one relationship with the number of keys that work, so given K possible keys, only K × (M/N) of them will "work". One of these is the correct key, the rest are spurious.
Since M/N gets arbitrarily small as the length L of the message increases, there is eventually some L that is large enough to make the number of spurious keys equal to zero. Roughly speaking, this is the L that makes KM/N=1. This L is the unicity distance.
## Relation with key entropy and plaintext redundancy
The unicity distance can equivalently be defined as the minimum amount of ciphertext required to permit a computationally unlimited adversary to recover the unique encryption key.[1]
The expected unicity distance can then be shown to be:[1]
${\displaystyle U=H(k)/D}$
where U is the unicity distance, H(k) is the entropy of the key space (e.g. 128 for 2128 equiprobable keys, rather less if the key is a memorized pass-phrase). D is defined as the plaintext redundancy in bits per character.
Now an alphabet of 32 characters can carry 5 bits of information per character (as 32 = 25). In general the number of bits of information per character is log2(N), where N is the number of characters in the alphabet and log2 is the binary logarithm. So for English each character can convey log2(26) = 4.7 bits of information.
However the average amount of actual information carried per character in meaningful English text is only about 1.5 bits per character. So the plain text redundancy is D = 4.7 − 1.5 = 3.2.[1]
Basically the bigger the unicity distance the better. For a one time pad of unlimited size, given the unbounded entropy of the key space, we have ${\displaystyle U=\infty }$, which is consistent with the one-time pad being unbreakable.
### Unicity distance of substitution cipher
For a simple substitution cipher, the number of possible keys is 26! = 4.0329 × 1026 = 288.4, the number of ways in which the alphabet can be permuted. Assuming all keys are equally likely, H(k) = log2(26!) = 88.4 bits. For English text D = 3.2, thus U = 88.4/3.2 = 28.
So given 28 characters of ciphertext it should be theoretically possible to work out an English plaintext and hence the key.
## Practical application
Unicity distance is a useful theoretical measure, but it doesn't say much about the security of a block cipher when attacked by an adversary with real-world (limited) resources. Consider a block cipher with a unicity distance of three ciphertext blocks. Although there is clearly enough information for a computationally unbounded adversary to find the right key (simple exhaustive search), this may be computationally infeasible in practice.
The unicity distance can be increased by reducing the plaintext redundancy. One way to do this is to deploy data compression techniques prior to encryption, for example by removing redundant vowels while retaining readability. This is a good idea anyway, as it reduces the amount of data to be encrypted.
Another way to increase the unicity distance is to increase the number of possible valid sequences in the files as it is read. Since if for at least the first several blocks any bit pattern can effectively be part of a valid message then the unicity distance has not been reached. This is possible on long files when certain bijective string sorting permutations are used, such as the many variants of bijective Burrows–Wheeler transforms.[dubious ]
Ciphertexts greater than the unicity distance can be assumed to have only one meaningful decryption. Ciphertexts shorter than the unicity distance may have multiple plausible decryptions. Unicity distance is not a measure of how much ciphertext is required for cryptanalysis,[why?] but how much ciphertext is required for there to be only one reasonable solution for cryptanalysis. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 2, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.848983645439148, "perplexity": 718.3927204078728}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-13/segments/1490218188926.39/warc/CC-MAIN-20170322212948-00173-ip-10-233-31-227.ec2.internal.warc.gz"} |
https://www.maplesoft.com/support/help/Maple/view.aspx?path=dsolve%2Fnumeric%2FBVP | BVP - Maple Help
dsolve/numeric/BVP
find numerical solution of ODE boundary value problems
Calling Sequence dsolve(odesys, numeric, vars, options)
Parameters
odesys - set or list; ordinary differential equation(s) and boundary conditions numeric - name; instruct dsolve to find a numerical solution vars - (optional) any indeterminate function of one variable, or a set or list of them, representing the unknowns of the ODE problem options - (optional) equations of the form keyword = value
Description
• The dsolve command with the numeric or type=numeric option on a real-valued two-point boundary value problem (BVP), finds a numerical solution for the ODE or ODE system BVP.
• The type of problem (BVP or IVP) is automatically detected by dsolve, and an applicable algorithm is used. The optional equation method=bvp[submethod] indicates that a specific BVP solver is to be used. The available submethods are traprich, trapdefer, midrich, and middefer. The first two methods, traprich and trapdefer,are trapezoid methods that use Richardson extrapolation enhancement or deferred correction enhancement, respectively. The remaining two methods, midrich and middefer, are midpoint methods with the same enhancement schemes.
There are two major considerations when choosing a submethod for a BVP. The trapezoid submethods are generally more efficient for typical problems, but the midpoint submethods are capable of handling harmless end-point singularities that the trapezoid submethods cannot. For the enhancement schemes, Richardson extrapolation is generally faster, but deferred corrections uses less memory on difficult problems.
• The available methods are fairly general, and should work on a variety of BVPs. They are not well suited to solve BVPs that are stiff or have solutions with singularities in their higher order derivatives.
• The solution method is capable of handling both linear and nonlinear BVPs with fixed, periodic, and even nonlinear boundary conditions. For nonlinear boundary conditions, however, it may be necessary to provide an initial solution profile that approximately satisfies the boundary conditions (see 'approxsoln' below). The method is also capable of handling BVP systems with undetermined parameters, given a sufficient number of boundary conditions to determine their values.
• Computation can be performed in both hardware precision and arbitrary precision, based on the setting of Digits. If Digits is smaller than the hardware precision for the machine, then computations are performed in hardware precision (see evalhf). If Digits is larger, then computations are performed in Maple floating point. In both cases, many of the more computationally intensive steps are performed in compiled external libraries.
• The return value of dsolve and the manipulation of the input system is controlled by the following three optional equations, which are discussed in dsolve[numeric].
'output' = keyword or array 'known' = name or list of names 'optimize' = boolean
In addition to the output options available for all numerical ODE problems, the option output=mesh is also available. It specifies that dsolve return an array-form output where independent variable values are chosen as the discrete mesh used internally by the method. This also has the effect of changing the interpolant default to false because only the discrete solution is required. See interpolant below.
The 'known' option specifies user-defined known functions, and is discussed in dsolve[numeric].
Options
• The options listed below are specific to BVP and include options to control the solution process, the accuracy of the result, and the initial mesh or solution profile to be used.
'abserr' = numeric 'range' = numeric..numeric 'adaptive' = boolean 'maxmesh' = integer 'initmesh' = integer 'approxsoln' = array, list or procedure 'continuation' = name 'mincont' = numeric 'interpolant' = boolean
'abserr'= numeric
Numeric value that gives an absolute error tolerance for the solution. In all but exceptional cases the true solution should be within the error tolerance value of the continuous approximate solution obtained by the method. The default value of abserr is Float(1,-6).
Note: This is an absolute error tolerance, so if the scale of the problem is such that the solution values are much smaller/larger than unitary, this parameter requires adjustment.
As for IVPs (see dsolve[numeric,IVP]), the system is converted to a first order system internally before the numerical solution is computed. The absolute error tolerance is applied to all components of the converted system.
'range'= numeric..numeric
Gives the left and right boundary points of the solution interval in the form leftpt..rightpt. This enables the method to be used to compute the solution of an initial value problem over a fixed interval using the absolute global error bound specified by abserr.
Boolean value that determines whether mesh adaptation is used to obtain the solution. By default this is true.
The method applied is based on arc-length, with additional rules to prevent adjacent steps from changing their size too rapidly, restrictions on the largest and smallest allowable step sizes as compared with the corresponding fixed step size, and restrictions preventing the mesh points near the boundaries from becoming too widely spaced.
Note: Some problems work better with fixed step-size meshes.
'maxmesh'= integer
Integer value that determines the maximum number of points dsolve uses to compute the numerical solution. The numeric BVP solver internally uses a discrete mesh of points to calculate the approximate solution, which is adjusted as greater accuracy is required. If the desired accuracy cannot be obtained with the current limitation imposed by maxmesh, an error is returned. The default value for maxmesh is $128$. Its value must be between $32$ and $134217728$.
'initmesh'= integer
Integer value that determines the number of points dsolve uses to compute the initial solution profile. In some cases, the default initial $8$ point mesh does not have sufficient resolution to obtain the initial solution profile, so increasing this value can give a solution when the default value does not. Its value must be between $8$ and $134217728$.
'approxsoln'= array, list or procedure
Argument that enables specification of an initial approximate discrete solution to be used as a starting point for the problem. There are many forms that this argument can take.
The simplest forms are the output of another dsolve/numeric computation when output is specified as an array (Matrix form output), or as a procedure (procedurelist, listprocedure, or operator output).
Another form is as a two-dimensional array where the names of the dependent variables and independent variables are given in the first column, followed by their values at different mesh points in the following columns. All dependent variables in the (converted to first order) system, must be present. This form can also be specified using nested lists.
The final form is as a list of equations that describe the initial solution profile as functions of the independent variable. For example, for a second order BVP in $u\left(x\right)$, this could be specified as $\left[u\left(x\right)=f\left(x\right)\right]$ or as $\left[u\left(x\right)=f\left(x\right),\frac{ⅆ}{ⅆx}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}u\left(x\right)=g\left(x\right)\right]$, where the $f\left(x\right),g\left(x\right)$ are fully determined functions of $x$. In the former case, the required derivative values of $u\left(x\right)$ are computed by evaluation of the derivative of $f\left(x\right)$.
In the cases with a discrete solution given in array form, the values of the independent variable must always be provided at either boundary, in increasing order over the solution region, and at a minimum of $8$ distinct points. In addition, the specification of a discrete approximate solution cannot be used in combination with initmesh.
For systems with free parameters (determined through interaction with the boundary conditions) it is suggested that approximate values for the parameters also be provided.
'continuation'= name
Argument that allows solution of a BVP via a continuous transformation from an easier problem to the desired problem. This method is used in obtaining an initial solution profile, and is most helpful for problems for which the Newton iteration for the initial solution approximation does not converge. The continuation option provides the name for the continuation parameter for the problem. The continuation problem must be constructed so that the parameter c, when varied from $0$ to $1$, defines a different BVP for each value of c, where $c=0$ represents the simpler problem, and $c=1$ represents the problem to be solved. The continuation parameter can be present in the differential equation, the values for the boundary conditions, or both. Two examples of the use of continuation for the solution of BVP problems can be found in dsolve[numeric_bvp,advanced].
For best results, the continuation problem should be constructed so that the BVP solutions vary continuously with the parameter, and so that the rate of change of the solution, with respect to the parameter, is very roughly constant over the range $c=0..1$.
'mincont'= numeric
Argument that provides a minimum value for the allowed change in the continuation parameter when computing the initial solution profile. The value must be positive, and less than or equal to $\frac{1}{10}$. The default value is $\frac{1}{100}$. This option is valid only when continuation has also been specified.
For some discussion of difficult BVP problems, and possible solutions, see dsolve[numeric_bvp,advanced].
'interpolant'= boolean
Boolean that is true by default, and specifies that the solution should be refined until an interpolation of the solution gives the requested accuracy. When this is false, the solution is improved until only the discrete solution has the requested accuracy. Also see the output=mesh argument.
• Results can be plotted by using the function odeplot in the plots package.
Examples
Linear boundary value problem:
> $\mathrm{dsol1}≔\mathrm{dsolve}\left(\left\{\mathrm{diff}\left(y\left(x\right),x,x\right)-2y\left(x\right)=0,y\left(0\right)=1.2,y\left(1\right)=0.9\right\},\mathrm{numeric}\right)$
${\mathrm{dsol1}}{≔}{\mathbf{proc}}\left({\mathrm{x_bvp}}\right)\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{...}\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{\mathbf{end proc}}$ (1)
> $\mathrm{dsol1}\left(0\right)$
$\left[{x}{=}{0.}{,}{y}{}\left({x}\right){=}{1.20000000000000}{,}\frac{{ⅆ}}{{ⅆ}{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{y}{}\left({x}\right){=}{-1.25251895272792}\right]$ (2)
> $\mathrm{dsol1}\left(0.2\right)$
$\left[{x}{=}{0.2}{,}{y}{}\left({x}\right){=}{0.994463627112648}{,}\frac{{ⅆ}}{{ⅆ}{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{y}{}\left({x}\right){=}{-0.816528958014159}\right]$ (3)
> $\mathrm{dsol1}\left(0.5\right)$
$\left[{x}{=}{0.5}{,}{y}{}\left({x}\right){=}{0.832942089176703}{,}\frac{{ⅆ}}{{ⅆ}{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{y}{}\left({x}\right){=}{-0.276385195570455}\right]$ (4)
> $\mathrm{dsol1}\left(1\right)$
$\left[{x}{=}{1.}{,}{y}{}\left({x}\right){=}{0.900000000000000}{,}\frac{{ⅆ}}{{ⅆ}{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{y}{}\left({x}\right){=}{0.555701111490340}\right]$ (5)
Nonlinear boundary value problem:
> $\mathrm{deq2}≔\mathrm{diff}\left(y\left(x\right),x,x\right)+\frac{\left(2+{y\left(x\right)}^{2}\right)y\left(x\right)}{1+{y\left(x\right)}^{2}}=1$
${\mathrm{deq2}}{≔}\frac{{{ⅆ}}^{{2}}}{{ⅆ}{{x}}^{{2}}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{y}{}\left({x}\right){+}\frac{\left({2}{+}{{y}{}\left({x}\right)}^{{2}}\right){}{y}{}\left({x}\right)}{{1}{+}{{y}{}\left({x}\right)}^{{2}}}{=}{1}$ (6)
> $\mathrm{bc2}≔y\left(0\right)=0,y\left(2\right)=3:$
> $\mathrm{dsol2}≔\mathrm{dsolve}\left(\left\{\mathrm{bc2},\mathrm{deq2}\right\},\mathrm{numeric},\mathrm{output}=\mathrm{listprocedure}\right)$
${\mathrm{dsol2}}{≔}\left[{x}{=}{\mathbf{proc}}\left({x}\right)\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{...}\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{\mathbf{end proc}}{,}{y}{}\left({x}\right){=}{\mathbf{proc}}\left({x}\right)\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{...}\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{\mathbf{end proc}}{,}\frac{{ⅆ}}{{ⅆ}{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{y}{}\left({x}\right){=}{\mathbf{proc}}\left({x}\right)\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{...}\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{\mathbf{end proc}}\right]$ (7)
> $\mathrm{fy}≔\mathrm{subs}\left(\mathrm{dsol2},y\left(x\right)\right)$
${\mathrm{fy}}{≔}{\mathbf{proc}}\left({x}\right)\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{...}\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{\mathbf{end proc}}$ (8)
> $\left[\mathrm{seq}\left(\mathrm{fy}\left(\frac{2i}{4}\right),i=0..4\right)\right]$
$\left[{0.}{,}{1.20426489602605}{,}{2.24834461794798}{,}{2.89441120924878}{,}{3.00000000000000}\right]$ (9)
Using BVP Solver for an IVP:
> $\mathrm{dsys3}≔\mathrm{diff}\left(y\left(x\right),x\right)-y\left(x\right)=0,y\left(1\right)=1$
${\mathrm{dsys3}}{≔}\frac{{ⅆ}}{{ⅆ}{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{y}{}\left({x}\right){-}{y}{}\left({x}\right){=}{0}{,}{y}{}\left({1}\right){=}{1}$ (10)
> $\mathrm{dsol3}≔\mathrm{dsolve}\left(\left\{\mathrm{dsys3}\right\},\mathrm{numeric},\mathrm{method}=\mathrm{bvp},\mathrm{range}=0..1,\mathrm{abserr}=1.×{10}^{-10}\right)$
${\mathrm{dsol3}}{≔}{\mathbf{proc}}\left({\mathrm{x_bvp}}\right)\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{...}\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{\mathbf{end proc}}$ (11)
> $\mathrm{dsol3}\left(0\right)$
$\left[{x}{=}{0.}{,}{y}{}\left({x}\right){=}{0.367879441157275}\right]$ (12)
> $\mathrm{evalf}\left[11\right]\left(\mathrm{exp}\left(-1\right)\right)$
${0.36787944117}$ (13)
Boundary value problem with an unknown parameter:
> $\mathrm{dsys4}≔\mathrm{diff}\left(y\left(x\right),x,x\right)-ay\left(x\right)=0,y\left(0\right)=1,y\left(1\right)=1,\mathrm{D}\left(y\right)\left(0\right)=2$
${\mathrm{dsys4}}{≔}\frac{{{ⅆ}}^{{2}}}{{ⅆ}{{x}}^{{2}}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{y}{}\left({x}\right){-}{a}{}{y}{}\left({x}\right){=}{0}{,}{y}{}\left({0}\right){=}{1}{,}{y}{}\left({1}\right){=}{1}{,}{\mathrm{D}}{}\left({y}\right){}\left({0}\right){=}{2}$ (14)
> $\mathrm{dsol4}≔\mathrm{dsolve}\left(\left\{\mathrm{dsys4}\right\},\mathrm{numeric},\mathrm{output}=\mathrm{operator}\right)$
${\mathrm{dsol4}}{≔}\left[{x}{=}{\mathbf{proc}}\left({x}\right)\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{...}\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{\mathbf{end proc}}{,}{y}{=}{\mathbf{proc}}\left({x}\right)\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{...}\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{\mathbf{end proc}}{,}{\mathrm{D}}{}\left({y}\right){=}{\mathbf{proc}}\left({x}\right)\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{...}\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{\mathbf{end proc}}{,}{a}{=}{\mathbf{proc}}\left({x}\right)\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{...}\phantom{\rule[-0.0ex]{0.5em}{0.0ex}}{\mathbf{end proc}}\right]$ (15)
> $\mathrm{dsol4}\left(0\right)$
$\left[{x}{=}{0}{,}{y}{}\left({0}\right){=}{1.00000000000000}{,}{\mathrm{D}}{}\left({y}\right){}\left({0}\right){=}{2.00000000000000}{,}{a}{}\left({0}\right){=}{-2.96069553617247}\right]$ (16)
> $\mathrm{dsol4}\left(0.5\right)$
$\left[{x}{=}{0.5}{,}{y}{}\left({0.5}\right){=}{1.53330815132594}{,}{\mathrm{D}}{}\left({y}\right){}\left({0.5}\right){=}{5.80015080018856}{×}{{10}}^{{-11}}{,}{a}{}\left({0.5}\right){=}{-2.96069553617247}\right]$ (17)
References
Ascher, U.; Mattheij, R.; and Russell, R. "Numerical Solution of Boundary Value Problems for Ordinary Differential Equations." SIAM Classics in Applied Mathematics. Vol. 13. (1995).
Ascher, U., and Petzold, L. "Computer Methods for Ordinary Differential Equations and Differential-Algebraic Equations." SIAM, Philadelphia. 1998. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 56, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8679888248443604, "perplexity": 689.6131664845852}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030337971.74/warc/CC-MAIN-20221007045521-20221007075521-00266.warc.gz"} |
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