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The Normandy field study on juvenile osteochondral conditions: conclusions regarding the influence of genetics, environmental conditions and management, and the effect on performance.
Juvenile osteochondral conditions (JOCC) have a major impact on the equine industry and include many musculoskeletal disorders of the young horse, of which osteochondrosis (OC) is the most prominent. The Breeding, Osteochondral Status and Athletic Career (BOSAC) project is the first large, comprehensive, longitudinal field study on the subject conducted in three breeds of performance horses (Thoroughbreds, Standardbred Trotters and Warmbloods) that were monitored in their natural environment where they were reared under common field conditions. The BOSAC study used a radiographic protocol designed for field use coupled to an internally validated severity scoring system, providing weighted radiographic findings as the primary outcome measure. The natural courses of various JOCC appear to differ, according to the joint and condition involved. Genetically, there were also large differences with moderate heritabilities in the tarsocrural and metacarpophalangeal/metatarsophalangeal joints and virtually no heritability for femoropatellar OC. There was a strong influence of exercise history (as an environmental condition) on the manifestation and natural course of JOCC. In the younger age class (<6months) lack of exercise or irregular exercise had a negative effect, as had exposure to excessive exercise. In the yearling category, (exercise-associated) intrinsic trauma seemed to be the most important negative factor. In terms of later function, the association of a poor radiographic score with poorer performance in racing Trotters could be demonstrated. PMID:23639367
van Weeren, P Renť; Denoix, Jean-Marie
Environmental conditions in the Late Cretaceous African Tethys: conclusions from a microscopic-microchemical study of ooidal ironstones from Egypt, Sudan and Nigeria
NASA Astrophysics Data System (ADS)
Two types of ooidal ironstone deposits, all of Late Cretaceous age, were recognised in an area trending from Nigeria in a northeasterly direction via Sudan to Egypt. The two types of ironstones are of the kaolinite-type deposits (Agbaja area, Bida area, Sokoto and Potiskum, Nigeria; Shendi and Wadi Haifa, Sudan; and Kalabscha, Egypt) and of the chamosite-type deposits (Aswan, Egypt and Okigwe, Nigeria). Post-diagenetic ferruginisation of these deposits is reflected in only small variations in the chemical composition of the two types. Obvious differences include the varying MgO concentrations, which are considerably higher in the chamosite-type (in the range from ė0.5-6.75 wt%). In the kaolinite-type, MgO varies from 0.0 to ė0.4 wt%. One of the principal characteristics of the chamosite-type deposits is the occurrence of fossils, especially of brecciated shell material and bioturbation. These features are unknown in the kaolinite-type. In both types, pyrite and siderite are common constituents. These minerals are of diagenetic origin and were formed under reducing conditions in the presence of either chamositic clay minerals or kaolinite. The protoliths of both the kaolinite and the chamositic types were lateritic weathered rocks of the hinterland, transported via fluvial drainage systems and deposited in marine basins. The differences of the two types have been explained by the attendant environmental conditions. The environment of the chamosite-type is compatible with fully marine conditions and normal salinity, resulting in the availability of Mg leading to the formation of chamositic clay during diagenesis. The environment of the kaolinite-type is thought to be a marginal basin with high river discharge and thus lower salinity with zero or negligibly low Mg concentration. In this environment, a diagenetic transformation of the sedimentary kaolinite precorsur into chamositic clay failed to occur. The model is supported by the distribution patterns of the two ironstone types. Within the study area, the chamositic-types are located at the extreme positions and are thus closest to the open sea where fully marine conditions are most likely to have occurred.
MŁcke, Arno
Shuttle near-field environmental impacts - Conclusions and observations for launching at other locations
NASA Technical Reports Server (NTRS)
Near field and far field environmental monitoring activities extending from the first launch of the Space Shuttle at the Kennedy Space Center have provided a database from which conclusions can now be drawn for short term, acute effects of launch and, to a lesser degree, long term cumulative effects on the natural environment. Data for the first 15 launches of the Space Shuttle from Kennedy Space Center Pad 39A are analyzed for statistical significance and reduced to graphical presentations of individual and collective disposition isopleths, summarization of observed environmental impacts (e.g., vegetation damage, fish kills), and supporting data from specialized experiments and laboratory analyses. Conclusions are drawn with regard to the near field environment at Pad A, the effects on the lagoonal complex, and the relationships of these data and conclusions to upcoming operations at Complex 39 Pad B where the environment is significantly different. The paper concludes with a subjective evaluation of the likely impacts at Vandenberg Space Launch Complex 6 for the first Shuttle launch next year.
Koller, A. M., Jr.; Knott, W. M.
Environmental conditions affecting the athlete.
The athlete is exposed to a number of environmental conditions that may affect performance and health. The sports physical therapist must be aware of the effects of these conditions on the performance and well-being of athletes under his/her care. Decisions about an individual's participation and decisions about the safety of holding an event are within the scope of practice of a sports physical therapist. Additionally, the athlete looks to the sports physical therapist for training guidelines for events in various environmental conditions. A literature search was performed to determine the relevant issues related to sports participation in hot and cold environments. The current body of knowledge in these areas is presented to guide sports physical therapists in training and advising athletes in their care. These areas include thermoregulation, heat, cold, fluid replacement, and clothing considerations. PMID:7742842
Thein, L A
NSDL National Science Digital Library
Drawing conclusions involves comparing initial ideas with new evidence and then deciding whether the ideas fit or need to be changed. It is the key to the investigation, where mental and practical activity comes together. This is how scientists approach i
Klentschy, Michael P.
Smallholder technical efficiency controlling for environmental production conditions
Smallholder agricultural production depends heavily on environmental production conditions that are largely exogenously determined. Yet, few data sets collect necessary, detailed information on environmental production conditions. This oversight raises the spectre of likely omitted variables bias because farmers' input choices typically respond in part to environmental conditions. Moreover, because environmental production conditions are rarely symmetrically distributed, the omission also generally
Shane M. Sherlund; Christopher B. Barrett; Akinwumi A. Adesina
Cross-taxon congruence and environmental conditions
BACKGROUND: Diversity patterns of different taxa typically covary in space, a phenomenon called cross-taxon congruence. This pattern has been explained by the effect of one taxon diversity on taxon diversity, shared biogeographic histories of different taxa, and\\/or common responses to environmental conditions. A meta-analysis of the association between environment and diversity patterns found that in 83 out of 85 studies,
Carolina Toranza; MatŪas Arim
The primary objective of novelty detection is to examine a system's dynamic response to determine if the system significantly deviates from an initial baseline condition. In reality, the system is often subject to changing environmental and operation conditions that affect its dynamic characteristics. Such variations include changes in loading, boundary conditions, temperature, and moisture. Most damage diagnosis techniques, however, generally neglect the effects of these changing ambient conditions. Here, a novelty detection technique is developed explicitly taking into account these natural variations of the system in order to minimize false positive indications of true system changes. Auto-associative neural networks are employed to discriminate system changes of interest such as structural deterioration and damage from the natural variations of the system.
What environmental conditions encourage shallow mesoscale organization?
NASA Astrophysics Data System (ADS)
From observations, shallow trade-wind precipitation was found to be associated with mesoscal arcs, which encircled cloud-free cold pools. Here several WRF-LES idealized simulations have been conducted to investigate the factors affecting the mesoscale organizations of shallow trade wind cumuli, including wind shear, cloud droplet number concentration (CDNC), and environmental moisture. Each of these simulations, employing RICO environment profile, is a 12-hour run in a 30km*30km*4km domain with resolution of 100m horizontally and ~80m vertically. Environment having large wind shear favors the formation of mesoscale organization, whereas shallow cumuli randomly scatter in the environment with small wind shear. Under the former conditions, the wind shear induced separation of cumulus updraft and rain-containing downdraft stimulates the development of cumulus aloft and the attendant cold pool near the surface. But in all wind shear cases, cloud fraction, cloud- and domain-averaged LWP just have a little difference. Given approximately the same amount of water vapor content, CDNC determines the size of cloud droplets and thereafter the precipitation, by suppressing or benefiting the coalescence-collision among cloud droplets. Lack of enough precipitation, in highly aerosol-burdened environment, weakens the cold pool and associated mesoscale organization of shallow cumuli. Moisture is an important constraint on the growth of shallow cumuli. In our simulations with higher environmental moisture, cloud fraction, cloud- and domain- averaged LWP increases, and more precipitation falls down to the surface. Attendant cold pools and associated mesoscale arcs come up much earlier, and they also become stronger and span vaster. Furthermore, the expansion of cold pools, by inhibiting new formation of clouds due to the negative buoyancy in it, also lowers cloud fraction, cloud- and domain averaged LWP.
Wang, X.; Zuidema, P.
Environmental conditions and reproductive health outcomes
Environmental exposures range across multiple domains to affect human health. In an effort to learn how environmental factors combine to contribute to health outcomes we constructed a multiple environmental domain index (MEDI) for use in health research. We used principal compone...
Degradation In Relation To Environmental Conditions
NASA Astrophysics Data System (ADS)
One of the parts of the natural attenuation capacity of the soil is its degradation ca- pacity. Usually, the degradation capacity is determined by monitoring contaminant concentrations in the field. However, it is desirable to estimate the degradation ca- pacity of a soil beforehand. For such an estimate, the factors which have the highest influence on the degradation process of a specific contaminant must be known. To find the soil parameters which dominate the degradation behaviour of contaminants in the subsurface, an approach is proposed. The approach consists of 3 steps 1. Derive expected patterns of behaviour under different environmental conditions from litera- ture review. 2. Collect data from published degradation experiments. 3. Explore the dataset by means of statistical techniques. The expected patterns of behaviour are used as guidelines for the exploration of the dataset. Three types of results are derived from dataset exploration: 1. The degree of influence of a variable on the degradation rate is found by application of the analysis- of-variance technique. 2. Factors, summarizing the variables under consideration, can be derived by application of principal components analysis. 3. Relationships can be quantified for the whole dataset or for subsets of the dataset by regression analysis. The approach has been applied to atrazine degradation experiments (see also abstract EGS02-A-01204 for poster presentation). The results will be used as an example and to illustrate problems and solutions during processing. This project is part of a Ph.D. study carried out in the framework of Delft Cluster during the period 1999-2003.
Putters, B.
Crops Models for Varying Environmental Conditions
NASA Technical Reports Server (NTRS)
New variable environment Modified Energy Cascade (MEC) crop models were developed for all the Advanced Life Support (ALS) candidate crops and implemented in SIMULINK. The MEC models are based on the Volk, Bugbee, and Wheeler Energy Cascade (EC) model and are derived from more recent Top-Level Energy Cascade (TLEC) models. The MEC models simulate crop plant responses to day-to-day changes in photosynthetic photon flux, photoperiod, carbon dioxide level, temperature, and relative humidity. The original EC model allows changes in light energy but uses a less accurate linear approximation. The simulation outputs of the new MEC models for constant nominal environmental conditions are very similar to those of earlier EC models that use parameters produced by the TLEC models. There are a few differences. The new MEC models allow setting the time for seed emergence, have realistic exponential canopy growth, and have corrected harvest dates for potato and tomato. The new MEC models indicate that the maximum edible biomass per meter squared per day is produced at the maximum allowed carbon dioxide level, the nominal temperatures, and the maximum light input. Reducing the carbon dioxide level from the maximum to the minimum allowed in the model reduces crop production significantly. Increasing temperature decreases production more than it decreases the time to harvest, so productivity in edible biomass per meter squared per day is greater at nominal than maximum temperatures, The productivity in edible biomass per meter squared per day is greatest at the maximum light energy input allowed in the model, but the edible biomass produced per light energy input unit is lower than at nominal light levels. Reducing light levels increases light and power use efficiency. The MEC models suggest we can adjust the light energy day-to- day to accommodate power shortages or Lise excess power while monitoring and controlling edible biomass production.
Jones, Harry; Cavazzoni, James; Keas, Paul
Pilot Plant Environmental Conditions (OPDD Appendix C).
National Technical Information Service (NTIS)
This is Appendix C to the Pilot Plant Overall Plant design description document for the 10-MW pilot central receiver plant to be located at Barstow, California. The environmental design criteria to be used for plant design day performance, operational lim...
C. M. Randall M. E. Whitson J. V. Coggi
Environmental Condition and Cypress Canker Disease
Cypress canker by Seiridium cardinale (Wag.) Sutt. & Gibson is a disease particularly harmful for cypress trees in Tuscany where the land scape value of this species is very important. The paper reports on the relationship among S. cardinale and environmental factors that may influence the spreading of the fungus using GIS technology. The s tudy conduced in the neighbourhood
Matteo FEDUCCI; Nicola LUCHI
Environmental conditions and Puumala virus transmission in Belgium
Background Non-vector-borne zoonoses such as Puumala hantavirus (PUUV) can be transmitted directly, by physical contact between infected and susceptible hosts, or indirectly, with the environment as an intermediate. The objective of this study is to better understand the causal link between environmental features and PUUV prevalence in bank vole population in Belgium, and hence with transmission risk to humans. Our hypothesis was that environmental conditions controlling the direct and indirect transmission paths differ, such that the risk of transmission to humans is not only determined by host abundance. We explored the relationship between, on one hand, environmental variables and, on the other hand, host abundance, PUUV prevalence in the host, and human cases of nephropathia epidemica (NE). Statistical analyses were carried out on 17 field sites situated in Belgian broadleaf forests. Results Linear regressions showed that landscape attributes, particularly landscape configuration, influence the abundance of hosts in broadleaf forests. Based on logistic regressions, we show that PUUV prevalence among bank voles is more linked to variables favouring the survival of the virus in the environment, and thus the indirect transmission: low winter temperatures are strongly linked to prevalence among bank voles, and high soil moisture is linked to the number of NE cases among humans. The transmission risk to humans therefore depends on the efficiency of the indirect transmission path. Human risk behaviours, such as the propensity for people to go in forest areas that best support the virus, also influence the number of human cases. Conclusion The transmission risk to humans of non-vector-borne zoonoses such as PUUV depends on a combination of various environmental factors. To understand the complex causal pathways between the environment and disease risk, one should distinguish between environmental factors related to the abundance of hosts such as land-surface attributes, landscape configuration, and climate Ė i.e., host ecology, Ė and environmental factors related to PUUV prevalence, mainly winter temperatures and soil moisture Ė i.e., virus ecology. Beyond a threshold abundance of hosts, environmental factors favouring the indirect transmission path (soil and climate) can better predict the number of NE cases among humans than factors influencing the abundance of hosts.
Linard, Catherine; Tersago, Katrien; Leirs, Herwig; Lambin, Eric F
Environmental Conditions Responsible for Solar Activity.
National Technical Information Service (NTIS)
During the seven years that this program was active at Stanford University, the group working with Professor Sturrock investigated many aspects of the conditions responsible for solar activity. Their results are presented in detail in their publications. ...
P. A. Sturrock
Lunar Polar Environmental Testing: Regolith Simulant Conditioning
NASA Technical Reports Server (NTRS)
As ISRU system development approaches flight fidelity, there is a need to test hardware in relevant environments. Extensive laboratory and field testing have involved relevant soil (lunar regolith simulants), but the current design iterations necessitate relevant pressure and temperature conditions. Including significant quantities of lunar regolith simulant in a thermal vacuum chamber poses unique challenges. These include facility operational challenges (dust tolerant hardware) and difficulty maintaining a pre-prepared soil state during pump down (consolidation state, moisture retention).For ISRU purposes, the regolith at the lunar poles will be of most interest due to the elevated water content. To test at polar conditions, the regolith simulant must be doped with water to an appropriate percentage and then chilled to cryogenic temperatures while exposed to vacuum conditions. A 1m tall, 28cm diameter bin of simulant was developed for testing these simulant preparation and drilling operations. The bin itself was wrapped with liquid nitrogen cooling loops (100K) so that the simulant bed reached an average temperature of 140K at vacuum. Post-test sampling was used to determine desiccation of the bed due to vacuum exposure. Depth dependent moisture data is presented from frozen and thawed soil samples.Following simulant only evacuation tests, drill hardware was incorporated into the vacuum chamber to test auguring techniques in the frozen soil at thermal vacuum conditions. The focus of this testing was to produce cuttings piles for a newly developed spectrometer to evaluate. This instrument, which is part of the RESOLVE program science hardware, detects water signatures from surface regolith. The drill performance, behavior of simulant during drilling, and characteristics of the cuttings piles will be offered.
Kleinhenz, Julie Elise
Conditional Probability Analysis: A Statistical Tool for Environmental Analysis.
The use and application of environmental conditional probability analysis (CPA) is relatively recent. The first presentation using CPA was made in 2002 at the New England Association of Environmental Biologists Annual Meeting in Newport. Rhode Island. CPA has been used since the...
Improving Warfighters' Sustainment and Performance in Extreme Environmental Conditions.
National Technical Information Service (NTIS)
In this project, we have developed and verified experimental rat models capable of reproducing physiological responses to extreme environmental conditions, such as simulated high-altitude hypoxia, acute heat stress, and chronic cold stress, comparable to ...
I. Cernak J. LaManna K. Kregel Z. Xun
Flexible DCP interface. [environmental sensor and signal conditioning interface
NASA Technical Reports Server (NTRS)
The author has identified the following significant results. A user of an ERTS data collection system (DCS) must supply the sensors and signal-conditioning interface. The electronic interface must be compatible with the NASA-furnished data collection platform. A universal signal-conditioning system for use with a wide range of environmental sensors is described. The interface is environmentally and electronically compatible with the DCP and has operated satisfactorily for a complete winter wheat growing season in Kansas.
Kanemasu, E. T.; Schimmelpfenning, H.
Environmental conditions favoring ice pellet aggregation
NASA Astrophysics Data System (ADS)
Winter precipitation is an important issue for many countries because of its common occurrence and its potential for destructive consequences. However, correct prediction of the precipitation type when temperatures are near 0 įC is often difficult because many different types can occur. These different precipitation types can occur alone, in close succession, or in combination. This study examines one aspect of this overall issue, the ability of ice pellets to form aggregates through collisions with supercooled drops and the consequent reduction of freezing raindrops at the surface. This issue was examined using a bin model (initiated with a Marshall-Palmer precipitation size distribution) to model the collisions between ice pellets and supercooled rain drops as they fall through a refreezing layer to the surface. Under certain conditions, collisions aloft resulting in ice pellet aggregates can significantly reduce the number of supercooled drops that reach the surface. For example, a reduction of supercooled drop precipitation rate of 56% is achieved in an initial overall precipitation rate of 25 mm/h and this in turn leads to 40% of the ice pellets at the surface being aggregated particles. Lower precipitation rates and a higher proportion of particles that contain ice at the top of the layer lead to a smaller reduction in precipitation rates but not necessarily a smaller fraction of aggregation. These findings imply that the likelihood of ice pellet aggregation must be accounted for in order to predict freezing rain intensity.
Carmichael, H. E.; Stewart, R. E.; Henson, W.; Thťriault, J. M.
Environmental conditions responsible for solar activity
NASA Astrophysics Data System (ADS)
Solar coronal activity is of concern to the Air Force primarily because of the terrestrial effects of coronal mass ejections and solar flares. Coronal mass ejections can lead to geomagnetic disturbances that in turn cause magnetospheric substorms. This geomagnetic activity disturbs the ionosphere, especially in the polar regions, interfering with radio propagation. Ionizing radiation (UV and X-ray) and particle events from solar flares can also lead to ionospheric disturbances. Furthermore, major flares pose serious hazards to astronauts. During the past three years, the Stanford group has obtained significant theoretical insights into the driving mechanism of eruptive events in the solar corona. The question of what causes coronal eruptions inevitably leads to questions concerning the plasma conditions and magnetic field configurations in which eruptions occur. In particular, we have grappled with the long-standing issue of how the coronal plasma is maintained at a temperature of several million degrees, while the underlying surface of the sun that is visible in white light has a temperature of only a few thousand degrees. Our work over the past three years has taken us closer to the goal of being able to predict the imminent onset of solar flares and coronal mass ejections.
Sturrock, Peter A.
Environmental Enteropathy: Critical implications of a poorly understood condition
Environmental enteropathy (also called tropical enteropathy) is a subclinical condition caused by constant fecal-oral contamination and resulting in blunting of intestinal villi and intestinal inflammation. Although these histological changes were discovered decades ago, the clinical impact of environmental enteropathy is just starting to be recognized. The failure of nutritional interventions and oral vaccines in the developing world may be attributed to environmental enteropathy, as the intestinal absorptive and immunologic functions are significantly deranged. Here we review the existing literature and examine potential mechanisms of pathogenesis for this poorly understood condition.
Korpe, Poonum S.; Petri, William A.
Mobility of capped silver nanoparticles under environmentally relevant conditions.
The mobility and deposition of capped silver (Ag) nanoparticles (NPs) on silica surfaces were characterized over a wide range of pH and ionic strength (IS) conditions, including seawater and freshwater. Two common organic capping agents (citrate and PVP) were evaluated. Both the capped Ag NPs and the silica surfaces were negatively charged under these environmentally relevant conditions, resulting in net repulsive electrostatics under most conditions. The steric repulsion introduced by the capping agents significantly reduced aggregation and deposition. In addition, the presence of natural organic matter in solution further decreased the deposition of either Ag NP on silica. Ag NPs were found to be highly mobile under these environmentally relevant conditions, with little or no deposition. PMID:22133047
Thio, Beng Joo Reginald; Montes, Milka O; Mahmoud, Mahmoud A; Lee, Dong-Woog; Zhou, Dongxu; Keller, Arturo A
What Environmental Conditions Lead to the Hatching of Brine Shrimp?
NSDL National Science Digital Library
The purpose of this investigation is to determine the best environmental conditions for the hatching and growth of brine shrimp. This level 4 inquiry activity was developed by a K-12 science teacher in the American Physiological Society√¬s 2010 Frontiers in Physiology Program. For more information on this program, please visit www.frontiersinphys.org.
Ms. Margaret Mauntel (Dubois Middle School)
Proceedings of "The Technical Workshop on Human Milk Surveillance and Research on Environmental Chemicals in the United States" was organized to develop state-of-the-science protocols describing the various aspects of such a program. The 2-day workshop was held at the Mi...
Environmental conditions influence eDNA persistence in aquatic systems.
Environmental DNA (eDNA) surveillance holds great promise for improving species conservation and management. However, few studies have investigated eDNA dynamics under natural conditions, and interpretations of eDNA surveillance results are clouded by uncertainties about eDNA degradation. We conducted a literature review to assess current understanding of eDNA degradation in aquatic systems and an experiment exploring how environmental conditions can influence eDNA degradation. Previous studies have reported macrobial eDNA persistence ranging from less than 1 day to over 2 weeks, with no attempts to quantify factors affecting degradation. Using a SYBR Green quantitative PCR assay to observe Common Carp ( Cyprinus carpio ) eDNA degradation in laboratory mesocosms, our rate of Common Carp eDNA detection decreased over time. Common Carp eDNA concentration followed a pattern of exponential decay, and observed decay rates exceeded previously published values for aquatic macrobial eDNA. Contrary to our expectations, eDNA degradation rate declined as biochemical oxygen demand, chlorophyll, and total eDNA (i.e., from any organism) concentration increased. Our results help explain the widely divergent, previously published estimates for eDNA degradation. Measurements of local environmental conditions, consideration of environmental influence on eDNA detection, and quantification of local eDNA degradation rates will help interpret future eDNA surveillance results. PMID:24422450
Barnes, Matthew A; Turner, Cameron R; Jerde, Christopher L; Renshaw, Mark A; Chadderton, W Lindsay; Lodge, David M
ERIC Educational Resources Information Center
To help students learn how to interpret, infer, and speculate on conclusions, here is a week-long learning activity on "clue finding". A mitten, a bagful of debris and a few intriguing exercises with descriptive paragraphs show students that they use clues every day to draw conclusions and that they can extend this ability to analyze what theyÖ
Soloway, Rhoda K.
Beginning without a Conclusion.
ERIC Educational Resources Information Center
Describes a series of activities without conclusions to introduce scientific reasoning in a ninth grade physical science course. Uses popcorn popping to get students to think about the concepts of graphing, histograms, frequency, probability, and scientific methodology. (CW)
Frazier, Richard
33 CFR 148.710 - What environmental conditions must be satisfied?
Code of Federal Regulations, 2013 CFR
... 2013-07-01 false What environmental conditions must be satisfied...PORTS DEEPWATER PORTS: GENERAL Environmental Review Criteria for Deepwater Ports § 148.710 What environmental conditions must be...
Environmental surveillance of the US Department of Energy Oak Ridge Reservation and surrounding environs during 1986: Volume 1, summary and conclusions
Comprehensive environmental monitoring data for 1986 show a continuation of progress in bringing the three major Oak Ridge installations into full compliance with permits and regulations issued by governing agencies and with their advice and recommendations. At the same time, past practices under which hazardous and radioactive wastes were disposed of in ways that do not represent the best practice available today - and ways no longer acceptable to regulatory agencies - continue to have adverse impacts through continuing releases to the area environment. In some cases also, improvements in monitoring techniques and in the range of emissions and effluents that are sampled and analyzed lead to reevaluation of previous estimates of pollutant loadings and their potential health or environment effects. Efforts to clean up contaminated storage and disposal areas and to close disposal sites that do not meet current standards now or the focus of long-term, very large-scale remedial action efforts. Likewise, new and improved treatment and isolation systems for gaseous, liquid, and solid wastes contributes, each year, to continuing reductions in potentially harmful emissions and effluents from current operations. This measurable evidence provides a degree of confidence and assurance that the aggressive, long-term program of corrective actions and waste management improvements now under way will be successful in restoring and enhancing environmental quality in the future and in reducing the potential for any deleterious impacts on human health from current or past Oak Ridge operations. 46 refs., 276 figs.
Oakes, T.w.; Kimbrough, C.W.; Pritz, P.M.; Goodpasture, S.T.; Huang, S.F.; Gist, C.S.; Weber, C.W.; Aebisher, E.D.; O'Hara, F.M. Jr.
Turboprop aircraft performance response to various environmental conditions
NASA Astrophysics Data System (ADS)
This study evaluated aircraft and airfoil performance response to various environmental conditions. These conditions included clear air, warm rain, ice only, mixed phase and supercooled drops encountered during 19 separate flights. Supercooled droplets consisting of cloud, drizzle and rain sizes were the main focus of this study. Aircraft response was quantified by rates of change in aircraft rate-of-climb capability, lift and drag coefficients and lift over drag ratio. Airfoil degradation due to simulated ice shapes and drizzle ice roughness was measured in a wind tunnel for comparison. The aircraft performance parameters were compared to environmental hydrometeor parameters quantifying the environmental conditions. Results show that encounters with supercooled drizzle drops, or SCDD, resulted in maximum rates of performance degradation. These high rates of degradation forced the pilot to take evasive action within 5 minutes of entering these hazardous conditions. Encounters with supercooled cloud and rain sized drops resulted in minor to low rates of performance degradation whereas encounters with supercooled drops in low ice particle concentrations resulted in only minor rates of degradation. In addition, aircraft response to high ice particle concentrations and low liquid water, following an SCDD encounter, resulted in rapid performance recovery. The airfoil evaluations show similar results where the drizzle drop ice shape and simulated drizzle ice roughness resulted in the highest performance degradation. These evaluations also show that the most sensitive surface location is on the suction side between 6 and at least 11% of airfoil chord. Ice contaminations in this area are beyond the protective de-icing boots of most aircraft and lead to severe degradations in lift and drag characteristics. The results presented herein show a strong relationship between aircraft response and environmental parameters utilizing the larger drops in the hydrometeor distribution. The results suggest that the most severe icing is actually caused by drizzle sized drops as opposed to freezing rain. Furthermore, these results are similar to many twin-turboprop aircraft typically utilized by the commuter fleet.
Ashenden, Russell Allen
Can environmental conditions experienced in early life influence future generations?
The consequences of early developmental conditions for performance in later life are now subjected to convergent interest from many different biological sub-disciplines. However, striking data, largely from the biomedical literature, show that environmental effects experienced even before conception can be transmissible to subsequent generations. Here, we review the growing evidence from natural systems for these cross-generational effects of early life conditions, showing that they can be generated by diverse environmental stressors, affect offspring in many ways and can be transmitted directly or indirectly by both parental lines for several generations. In doing so, we emphasize why early life might be so sensitive to the transmission of environmentally induced effects across generations. We also summarize recent theoretical advancements within the field of developmental plasticity, and discuss how parents might assemble different 'internal' and 'external' cues, even from the earliest stages of life, to instruct their investment decisions in offspring. In doing so, we provide a preliminary framework within the context of adaptive plasticity for understanding inter-generational phenomena that arise from early life conditions. PMID:24807254
Burton, Tim; Metcalfe, Neil B
Can environmental conditions experienced in early life influence future generations?
The consequences of early developmental conditions for performance in later life are now subjected to convergent interest from many different biological sub-disciplines. However, striking data, largely from the biomedical literature, show that environmental effects experienced even before conception can be transmissible to subsequent generations. Here, we review the growing evidence from natural systems for these cross-generational effects of early life conditions, showing that they can be generated by diverse environmental stressors, affect offspring in many ways and can be transmitted directly or indirectly by both parental lines for several generations. In doing so, we emphasize why early life might be so sensitive to the transmission of environmentally induced effects across generations. We also summarize recent theoretical advancements within the field of developmental plasticity, and discuss how parents might assemble different Ďinternalí and Ďexternalí cues, even from the earliest stages of life, to instruct their investment decisions in offspring. In doing so, we provide a preliminary framework within the context of adaptive plasticity for understanding inter-generational phenomena that arise from early life conditions.
Burton, Tim; Metcalfe, Neil B.
Conclusions and suggested research
Although load management must be investigated and applied on each specific rail transit system, there are a few principles that are general enough to apply to any system. The conclusions drawn from the results of this research are given. Specific areas for research are also identified.
Not Available
Protection of chemolithoautotrophic bacteria exposed to simulated Mars environmental conditions
NASA Astrophysics Data System (ADS)
Current surface conditions (strong oxidative atmosphere, UV radiation, low temperatures and xeric conditions) on Mars are considered extremely challenging for life. The question is whether there are any features on Mars that could exert a protective effect against the sterilizing conditions detected on its surface. Potential habitability in the subsurface would increase if the overlaying material played a protective role. With the aim of evaluating this possibility we studied the viability of two microorganisms under different conditions in a Mars simulation chamber. An acidophilic chemolithotroph isolated from RŪo Tinto belonging to the Acidithiobacillus genus and Deinococcus radiodurans, a radiation resistant microorganism, were exposed to simulated Mars conditions under the protection of a layer of ferric oxides and hydroxides, a Mars regolith analogue. Samples of these microorganisms were exposed to UV radiation in Mars atmospheric conditions at different time intervals under the protection of 2 and 5 mm layers of oxidized iron minerals. Viability was evaluated by inoculation on fresh media and characterization of their growth cultures. Here we report the survival capability of both bacteria to simulated Mars environmental conditions.
Gůmez, Felipe; Mateo-MartŪ, Eva; Prieto-Ballesteros, Olga; MartŪn-Gago, Jose; Amils, Ricardo
The effect and role of environmental conditions on magnetosome synthesis.
Magnetotactic bacteria (MTB) are considered the model species for the controlled biomineralization of magnetic Fe oxide (magnetite, Fe3O4) or Fe sulfide (greigite, Fe3S4) nanocrystals in living organisms. In MTB, magnetic minerals form as membrane-bound, single-magnetic domain crystals known as magnetosomes and the synthesis of magnetosomes by MTB is a highly controlled process at the genetic level. Magnetosome crystals reveal highest purity and highest quality magnetic properties and are therefore increasingly sought after as novel nanoparticulate biomaterials for industrial and medical applications. In addition, "magnetofossils," have been used as both past terrestrial and potential Martian life biosignature. However, until recently, the general belief was that the morphology of mature magnetite crystals formed by MTB was largely unaffected by environmental conditions. Here we review a series of studies that showed how changes in environmental factors such as temperature, pH, external Fe concentration, external magnetic fields, static or dynamic fluid conditions, and nutrient availability or concentrations can all affect the biomineralization of magnetite magnetosomes in MTB. The resulting variations in magnetic nanocrystals characteristics can have consequence both for their commercial value but also for their use as indicators for ancient life. In this paper we will review the recent findings regarding the influence of variable chemical and physical environmental control factors on the synthesis of magnetosome by MTB, and address the role of MTB in the global biogeochemical cycling of iron. PMID:24575087
Moisescu, Cristina; Ardelean, Ioan I; Benning, Liane G
The effect and role of environmental conditions on magnetosome synthesis
Magnetotactic bacteria (MTB) are considered the model species for the controlled biomineralization of magnetic Fe oxide (magnetite, Fe3O4) or Fe sulfide (greigite, Fe3S4) nanocrystals in living organisms. In MTB, magnetic minerals form as membrane-bound, single-magnetic domain crystals known as magnetosomes and the synthesis of magnetosomes by MTB is a highly controlled process at the genetic level. Magnetosome crystals reveal highest purity and highest quality magnetic properties and are therefore increasingly sought after as novel nanoparticulate biomaterials for industrial and medical applications. In addition, ďmagnetofossils,Ē have been used as both past terrestrial and potential Martian life biosignature. However, until recently, the general belief was that the morphology of mature magnetite crystals formed by MTB was largely unaffected by environmental conditions. Here we review a series of studies that showed how changes in environmental factors such as temperature, pH, external Fe concentration, external magnetic fields, static or dynamic fluid conditions, and nutrient availability or concentrations can all affect the biomineralization of magnetite magnetosomes in MTB. The resulting variations in magnetic nanocrystals characteristics can have consequence both for their commercial value but also for their use as indicators for ancient life. In this paper we will review the recent findings regarding the influence of variable chemical and physical environmental control factors on the synthesis of magnetosome by MTB, and address the role of MTB in the global biogeochemical cycling of iron.
Moisescu, Cristina; Ardelean, Ioan I.; Benning, Liane G.
Strigolactones as mediators of plant growth responses to environmental conditions
Strigolactones (SLs) have been recently identified as a new group of plant hormones or their derivatives thereof, shown to play a role in plant development. Evolutionary forces have driven the development of mechanisms in plants that allow adaptive adjustments to a variety of different habitats by employing plasticity in shoot and root growth and development. The ability of SLs to regulate both shoot and root development suggests a role in the plant's response to its growth environment. To play this role, SL pathways need to be responsive to plant growth conditions, and affect plant growth toward increased adaptive adjustment. Here, the effects of SLs on shoot and root development are presented, and possible feedback loops between SLs and two environmental cues, light and nutrient status, are discussed; these might suggest a role for SLs in plants' adaptive adjustment to growth conditions.
Kapulnik, Yoram
Conclusions and Policy Directions,
This chapter briefly revisits the constraints and opportunities of mitigation and adaptation, and highlights and the multiple linkages, synergies and trade-offs between mitigation, adaptation and urban development. The chapter then presents future policy directions, focusing on local, national and international principles and policies for supporting and enhancing urban responses to climate change. In summary, policy directions for linking climate change responses with urban development offer abundant opportunities; but they call for new philosophies about how to think about the future and how to connect different roles of different levels of government and different parts of the urban community. In many cases, this implies changes in how urban areas operate - fostering closer coordination between local governments and local economic institutions, and building new connections between central power structures and parts of the population who have often been kept outside of the circle of consultation and discourse. The difficulties involved in changing deeply set patterns of interaction and decision-making in urban areas should not be underestimated. Because it is so difficult, successful experiences need to be identified, described and widely publicized as models for others. However, where this challenge is met, it is likely not only to increase opportunities and reduce threats to urban development in profoundly important ways, but to make the urban area a more effective socio-political entity, in general - a better city in how it works day to day and how it solves a myriad of problems as they emerge - far beyond climate change connections alone. It is in this sense that climate change responses can be catalysts for socially inclusive, economically productive and environmentally friendly urban development, helping to pioneer new patterns of stakeholder communication and participation.
Wilbanks, Thomas J [ORNL; Romero-Lankao, Paty [National Center for Atmospheric Research (NCAR); Gnatz, P [National Center for Atmospheric Research (NCAR)
Differential conditioning of environmental cues with amygdala kindling.
Recent evidence suggests that the pairing of environmental cues with kindling stimulation can affect the rate at which seizures develop. In the present study, the effect of differential conditioning was evaluated. Rats were kindled in either a black box or a highly illuminated white box. Half of the subjects in each of these groups (discrimination groups) was placed in the opposite box on separate days without receiving kindling stimulation. The remaining subjects (control groups) were placed only in the box in which they received stimulation. Subjects kindled in the white box developed stage 5 (clonic) seizures significantly faster than those kindled in the black box. Those subjects that received discrimination training with the white box positive kindled faster than all other groups. However, after reaching stage 5, both discrimination groups, regardless of which box was positive, had significantly shorter afterdischarge (AD) durations during threshold testing as compared with the control groups. Seizure thresholds did not differ for the different groups. No evidence for conditioned seizures was found. The results were discussed in terms of the potential facilitory and inhibitory effects of environmental cues on seizures. PMID:3698934
Freeman, F G; Mikulka, P J
Environmental factors affecting indole metabolism under anaerobic conditions.
The influence of physiological and environmental factors on the accumulation of oxindole during anaerobic indole metabolism was investigated by high-performance liquid chromatography. Under methanogenic conditions, indole was temporarily converted to oxindole in stoichiometric amounts in media inoculated with three freshwater sediments and an organic soil. In media inoculated with methanogenic sewage sludge, the modest amounts of oxindole detected at 35 degrees C reached higher concentrations and persisted longer when the incubation temperature was decreased from 35 to 15 degrees C. Also, decreasing the concentration of sewage sludge used as an inoculum from 50 to 1% caused an increase in the accumulation of oxindole from 10 to 75% of the indole added. Under denitrifying conditions, regardless of the concentration or source of the inoculum, oxindole appeared in trace amounts but did not accumulate during indole metabolism. In addition, denitrifying consortia which previously metabolized indole degraded oxindole with no lag period. Our data suggest that oxindole accumulation under methanogenic, but not under denitrifying conditions is caused by differences between relative rates of oxindole production and destruction.
Madsen, E L; Francis, A J; Bollag, J M
[Extracellular factors of bacterial adaptation to unfavorable environmental conditions].
Data on extracellular compounds of bacteria involved in their adaptation to unfavorable environmental conditions are reviewed, including high or low temperatures, growth-inhibiting or bactericidal concentrations of toxic substances (oxidants, phenols, and heavy metals) and antibiotics, deviation of pH values from optimum levels, and salinity of the medium. Chemically, the compounds identified belong to diverse types (proteins, hydrocarbons, organic acids, nucleotides, amino acids, lipopeptides, volatile substances, etc.). Most of them remain unidentified, and their properties are studied using biological testing. It is proposed to view extracellular adaptation factors (EAFs) as a new group of biologically active substances. EAFs may be divided into several subgroups by the mechanism of action. These subgroups include protectors (stabilizers), signaling molecules inducing defense responses, regulators (e.g., adhesion regulators) not acting as inducers, and antidotes (neutralizers). The fields of EAF study include screening (search for new compounds, using biological tests), identification, and research into mechanisms of action. EAFs may find utility in biotechnology, medicine, agriculture, and environmental protection. PMID:15455710
Nikolaev, Iu A
K, U, and Th behavior in Martian environmental conditions
NASA Technical Reports Server (NTRS)
The possibility of K, U, and Th content determination from orbit and in situ allows consideration of those elements as geochemical indicators in the planetary studies. In the case of Mars the unambiguous interpretations of such data in terms of igneous rocks are remarkably constrained by the widespread rock alteration and the existence of exogenic deposits. Besides, the terrestrial experience indicates that K, U, and Th contents could be used as indicators of environmental geochemical processes. Thus the determination of K, U, and Th contents in the Martian surface materials could provide the indirect data on the conditions of some exogenic geological processes. The speculations on the K, U, and Th behavior in the Martian environments show that aeolian and aqueous processes leads to the preferential accumulation of K, U, and Th in fine dust material. The separation of K, U, and Th on Mars is smaller in scale to that on Earth.
Zolotov, M. YU.; Krot, T. V.; Moroz, L. V.
Pervaporative irrigation: a flow rate driven by environmental conditions
NASA Astrophysics Data System (ADS)
Pervaporative irrigation allows in-situ treatment of low quality water (e.g. saline water) whilst simultaneously distributing water throughout the soil. The system is also low energy, requiring only that a positive head of water is maintained in a supply tank. To irrigate using this method a pervaporative polymer membrane is formed into a pipe, buried in the soil and filled with water. Water is transported across the membrane by the process of pervaporation whilst the transport of contaminants is retarded, thus reducing the risk of soil degradation due to the use of low water quality. Uniquely these systems also inherently provide a feedback mechanism by which crops can affect the irrigation rate. Such a system has significant possibilities to provide an irrigation pipe from which water is only applied when required, hence reducing the volume of water used. However such systems are currently not fully understood and, to be implemented effectively, the behaviour of the membrane in different environmental conditions must be quantified. From experimental results this work has identified the significance of vapour flows in predicting the flux from the irrigation system in dry soils. In a 15cm layer of sand, the presence of a desiccant above the soil doubled the flux from the pipe, but more than 70% of this mass was adsorbed by the desiccant. Experiments also show that the flux into typical top soil was greater than into sand because of the greater capacity of the top soil for water adsorption. This adsorption maintained a lower humidity in the soil, hence providing a larger gradient across the irrigation membrane and inducing a higher flux. Although there is some evidence that seeds can absorb water from vapour flows the possibility that plants also do this has not yet been explored. This technology provides future opportunities to explore the interaction of plants both with vapour flows, and with a system where the irrigation rate is influenced by the crop uptake and the surrounding environmental conditions.
Todman, L. C.; Mougros, C.; Ireson, A. M.; Butler, A. P.; Templeton, M. R.
Evaluating microbial indicators of environmental condition in Oregon rivers.
Traditional bacterial indicators used in public health to assess water quality and the Biolog system were evaluated to compare their response to biological, chemical, and physical habitat indicators of stream condition both within the state of Oregon and among ecoregion aggregates (Coast Range, Willamette Valley, Cascades, and eastern Oregon). Forty-three randomly selected Oregon river sites were sampled during the summer in 1997 and 1998. The public health indicators included heterotrophic plate counts (HPC), total coliforms (TC), fecal coliforms (FC) and Escherichia coli (EC). Statewide, HPC correlated strongly with physical habitat (elevation, riparian complexity, % canopy presence, and indices of agriculture, pavement, road, pasture, and total disturbance) and chemistry (pH, dissolved O2, specific conductance, acid-neutralizing capacity, dissolved organic carbon, total N, total P, SiO2, and SO4). FC and EC were significantly correlated generally with the river chemistry indicators. TC bacteria significantly correlated with riparian complexity, road disturbance, dissolved O2, and SiO2 and FC. Analyzing the sites by ecoregion, eastern Oregon was characterized by high HPC, FC, EC, nutrient loads, and indices of human disturbance, whereas the Cascades ecoregion had correspondingly low counts of these indicators. The Coast Range and Willamette Valley presented inconsistent indicator patterns that are more difficult to characterize. Attempts to distinguish between ecoregions with the Biolog system were not successful, nor did a statistical pattern emerge between the first five principle components and the other environmental indicators. Our research suggests that some traditional public health microbial indicators may be useful in measuring the environmental condition of lotic systems. PMID:11915970
Pennington, A T; Harding, A K; Hendricks, C W; Campbell, H M
NASA Technical Reports Server (NTRS)
This compilation of papers in this book represents approximately half of the works discussed at the MS&T 2010 symposium entitled Tools, Models, Databases, and Simulation Tools Developed and Needed to Realize the Vision of Integrated Computational Materials Engineering at Materials Science & Technology wherein five sessions comprised of 33 presentations was organized. The goal of the symposium was two fold To provide a forum in which current state-of-the-art methods for ICME (e.g., information informatics, experimentation, and modeling) could be openly discussed and critiqued by not only materials scientist but also structural engineers/researchers, component designers, industrial leaders and government program managers. To leave the symposium and in particular the panel discussion with a clear idea of the gaps and barriers (both technical, cultural and economical) that must be addressed in order for ICME to fully succeed. The organizers felt that these goals were met, as particularly evident by the standing room only attendance during a lively panel discussion session at the end of the Symposium. However it is the firm belief of the editors of this book that this symposium was merely a start in the right direction, and that subsequent conferences/symposium (e.g., First World Congress on Integrated Computational Materials Engineering to be held July 10-14, 2011 at Seven Springs Mountain Resort in Pennsylvania) must work hard to ensure that a truly diverse, multidisciplinary, community of researchers and practitioners are present and have ample opportunity for interaction. This will ensure that a proper balance between push and pull disciplines and technologies is maintained so that this emerging focus area, Integrated Computational Materials Engineering (ICME), has the greatest potential for success and impact on "system-level" payoffs. Similarly, a pro-active approach is required to reform historical modes of operation in industry, government and the academic sectors so as to facilitate multidisciplinary collaboration and to clearly articulate the vision and scope of ICME.
Arnold, Steven M.; Wong, Terry T.
ERIC Educational Resources Information Center
Examines the foreign policy of the Reagan administration. Discusses the critics of the Reagan doctrine, focusing on the criticisms launched against his weapons' policies. Analyzes the policy course of the Intermediate Range Nuclear Forces (INF) Treaty, outlining goals of the administration during the INF negotiations. Contends that Reagan'sÖ
Johnston, Whittle
NASA Astrophysics Data System (ADS)
Some say that an increase in security does not necessarily mean a further encroachment on privacy - indeed, security is necessary to protect personal data and our privacy. Networks must be secure, our personal devices, reliable, dependable and trustworthy. But security is a multifaceted term, with many dimensions. We are of the view that an increase in security most likely will encroach upon our privacy in an ambient intelligence world. Surveillance cameras will continue to proliferate. We assume that, whatever the law is, whatever privacy protections government and business say they honour, our telecommunications, e-mails and Internet usage will be monitored to an increasing degree. The same will be true of our interfaces with the world of ambient intelligence.
Ahonen, Pasi; Alahuhta, Petteri; Daskala, Barbara; Delaitre, Sabine; Hert, Paul De; Lindner, Ralf; Maghiros, Ioannis; Moscibroda, Anna; Schreurs, Wim; Verlinden, Michiel
\\u000a The various chapters of this book have covered the development of a range of theories in the theorem prover Isabelle. The\\u000a main unifying theme has been the use of infinitesimals as valuable tools that are once again respectable in mathematics. Infinitesimals\\u000a have been around for over 2 000 years and generally had a bad press. Their use has at times
Jacques Fleuriot
NASA Astrophysics Data System (ADS)
The main feature of the COST F3 Working Group was to identify structures that exhibit a non-linear behaviour. In this context, two benchmarks were proposed, namely, the VTT benchmark and the ECL benchmark.
Golinval, J. C.; Kerschen, G.; Lenaerts, V.; Thouverez, F.; Argoul, P.
Conclusive exclusion of quantum states
NASA Astrophysics Data System (ADS)
In the task of quantum state exclusion, we consider a quantum system prepared in a state chosen from a known set. The aim is to perform a measurement on the system which can conclusively rule that a subset of the possible preparation procedures cannot have taken place. We ask what conditions the set of states must obey in order for this to be possible and how well we can complete the task when it is not. The task of quantum state discrimination forms a subclass of this set of problems. Within this paper, we formulate the general problem as a semidefinite program (SDP), enabling us to derive sufficient and necessary conditions for a measurement to be optimal. Furthermore, we obtain a necessary condition on the set of states for exclusion to be achievable with certainty, and we give a construction for a lower bound on the probability of error. This task of conclusively excluding states has gained importance in the context of the foundations of quantum mechanics due to a result from Pusey, Barrett, and Rudolph (PBR). Motivated by this, we use our SDP to derive a bound on how well a class of hidden variable models can perform at a particular task, proving an analog of Tsirelson's bound for the PBR experiment and the optimality of a measurement given by PBR in the process. We also introduce variations of conclusive exclusion, including unambiguous state exclusion, and state exclusion with worst-case error.
Bandyopadhyay, Somshubhro; Jain, Rahul; Oppenheim, Jonathan; Perry, Christopher
Environmental safety conditions for mobile base stations in Alexandria.
The use of wireless communications devices e.g. cellular phones is increasing rapidly all over the world and in Egypt as well. This translates into a potentially significant public health problem: how far is the risk associated with these devices? Another risk is expected from the cellular towers or base stations, which transmit and receive these electromagnetic waves. Usually, these base stations should be constructed over residential buildings to cover all areas. Considering the increased public awareness about electromagnetic fields (EMF) exposure associated with these towers, this work aimed at investigation and evaluation of authorized environmental safety conditions for some mobile base stations in different districts of Alexandria city. The different mobile base stations were investigated for 12 standard safety specifications of the buildings' roofs on which mobile base stations are constructed. Although some of the standard specifications in the examined base stations were in compliance with standard specifications, some items were not in a safe condition. Only base stations F & G had complete safe conditions for all investigated items because of being erected on lighting towers of a sports stadium. On the other hand, base stations C, D, E, I, J, K, L1 & L2 needed a raise in the height of the antennas over buildings' roofs of 1-4.5 m. However, base stations C, D, H, K, L1 & L2 may pose a risk to near living population and consequently the towers have to be moved away. The violating distances are 3, 5.5, 3, 4.5, 4, 3 meters, respectively, while the environmental standard is 6 m. Therefore, the towers should be moved away from these populated areas Nevertheless, guided directions should be constructed in all base stations to warn close living population. Safety regulations as well as frequent inspection need to be applied, on both Egyptian mobile phone companies, to ensure the application of all standard specifications. A significant research effort is needed to assess the risk to human health of wireless communication devices. PMID:17216927
el-Shal, W; el-Sebaie, O
Fitness consequences of environmental conditions at different life stages in a long-lived vertebrate.
The predictive adaptive response (PAR) hypothesis proposes that animals adjust their physiology and developmental trajectory during early life in anticipation of their future environments. Accordingly, when environmental conditions in early life match environmental conditions during adulthood, individual fitness should be greater. Here, we test this hypothesis in a long-lived mammal, the roe deer, using data from two contrasting populations, intensively monitored for more than 35 years. In the highly productive site, the fitness of female roe deer increased with the quality of environment during adulthood and, contrary to predictions of PAR, individuals born in good conditions always outperformed those born under poor conditions. In the resource-limited site, the fitness of female roe deer born in poor years was better than those born in good conditions in poor years when the animals were adult, but not in good years. Although consistent with predictions of PAR, we showed that this pattern is likely to be a consequence of increased viability selection during the juvenile stage for animals born in poor years. While PARs are often advanced in evolutionary medicine, our findings suggest that detailed biological processes should be investigated before drawing conclusions about the existence of this phenomenon. PMID:24789898
Douhard, Mathieu; Plard, Floriane; Gaillard, Jean-Michel; Capron, Gilles; Delorme, Daniel; Klein, FranÁois; Duncan, Patrick; Loe, Leif Egil; Bonenfant, Christophe
Impact of Environmental Conditions on the Survival of Cryptosporidium and Giardia on Environmental Surfaces
The objective of this study was to find out the impact of environmental conditions on the survival of intestinal parasites on environmental surfaces commonly implicated in the transmission of these parasites. The study was performed by incubating Cryptosporidium and Giardia (oo)cysts on environmentally relevant surfaces such as brushed stainless steel, formica, ceramic, fabric, and skin. Parallel experiments were conducted using clean and soiled coupons incubated under three temperatures. The die-off coefficient rates (K) were calculated using first-order exponential formula. For both parasites, the fastest die-off was recorded on fabric, followed by ceramic, formica, skin, and steel. Die-off rates were directly correlated to the incubation temperatures and surface porosity. The presence of organic matter enhanced the survivability of the resting stages of test parasites. The decay rates calculated in this study can be used in models for public health decision-making process and highlights the mitigation role of hand hygiene agents in their prevention and control.
Alum, Absar; Absar, Isra M.; Asaad, Hamas; Rubino, Joseph R.; Ijaz, M. Khalid
Impact of environmental conditions on the survival of cryptosporidium and giardia on environmental surfaces.
The objective of this study was to find out the impact of environmental conditions on the survival of intestinal parasites on environmental surfaces commonly implicated in the transmission of these parasites. The study was performed by incubating Cryptosporidium and Giardia (oo)cysts on environmentally relevant surfaces such as brushed stainless steel, formica, ceramic, fabric, and skin. Parallel experiments were conducted using clean and soiled coupons incubated under three temperatures. The die-off coefficient rates (K) were calculated using first-order exponential formula. For both parasites, the fastest die-off was recorded on fabric, followed by ceramic, formica, skin, and steel. Die-off rates were directly correlated to the incubation temperatures and surface porosity. The presence of organic matter enhanced the survivability of the resting stages of test parasites. The decay rates calculated in this study can be used in models for public health decision-making process and highlights the mitigation role of hand hygiene agents in their prevention and control. PMID:25045350
Alum, Absar; Absar, Isra M; Asaad, Hamas; Rubino, Joseph R; Ijaz, M Khalid
Environmental Conditions on Mars at the end of the Noachian
NASA Astrophysics Data System (ADS)
Geological and morphological evidences show that liquid water or saline solution could have flowed on the Early Mars' surface, at the end of the Noachian (3.8 - 3.9 Gyr ago). However, while it is mostly thought that liquid water existed in the past, the environmental conditions such as the surface pressures and temperatures of this period and their variation are not known. We estimate the surface pressure values with the use of an atmospheric mass evolution model, which includes the effects of impacts erosion and volatiles delivery and non-thermal solar loss. Because of the uncertainties regarding the impact volatile delivery model and the efficiency of carbonate weathering since the end of the Noachian, estimated surface pressure on Mars at the end of the Noachian are between 0.25 bar and 2 bars. Latitudinal temperature profiles and surface pressure values are calculated for different orbital parameters. For this purpose, we use a one-dimensional energy balance model which includes meridional heat transport and greenhouse warming. Our model suggests that stable saline solutions can exist on early Mars only for surface pressures higher than 1.9 bar and with a strong greenhouse warming. For lower surface pressures and a weak greenhouse warming, saline solutions can flow sporadically at high latitudes during high obliquity periods.
Binh San Pham, LÍ; Karatekin, ÷zgŁr
Age at menarche: the influence of environmental conditions
NASA Astrophysics Data System (ADS)
Age at menarche was studied by the recollection method in two groups of Causasian Jewish high school girls, inhabitants of two towns in Israel, Safad and Elat. The two towns differ mainly in climatic conditions. The age at menarche was found to be significantly lower ( P<0.02) in the hot town of Elat than in the temperate town of Safad: 13.30Ī1.21 and 13.58Ī0.9 years, respectively (mean ĪSD). A significant association was found between the age at menarche and the town in which the girls lived. Accordingly, in the hot town of Elat, the percentage of girls who had their first menstrual cycle by the age of 12 years and earlier, was more than double that of the girls in Safad (17.9% and 7.1%, respectively). It is concluded that the environmental temperature, with or without any possible interaction of humidity, is probably responsible for the tendency for an earlier onset of menarche in girls living in the hot town of Elat.
Saar, E.; Shalev, C.; Dalal, I.; Sod-Moriah, U. A.
Severe local convective storms in Bangladesh: Part II.: Environmental conditions
NASA Astrophysics Data System (ADS)
This paper examines the environmental conditions of severe local convective storms during the pre-monsoon season (from March to May) in Bangladesh. We compared composite soundings on severe local convective storm days (SLCSD) with those on non-severe local convective storm days (NSLCSD) using rawinsonde data at 06 Bangladesh Standard Time (BST) in Dhaka (90.3įE and 23.7įN). Temperatures are rising in the lower layer and falling in the middle layer, and the amount of water vapor is significantly increasing in the lowest layer with southerly wind intensified on SLCSD compared with NSLCSD. This situation produces great thermal instability in the atmosphere on SLCSD. Convective parameters on SLCSD are computed with the rawinsonde data at 06 BST in Dhaka and compared with those on NSLCSD. The comparison shows that while most convective parameters related to thermal instability can discriminate between SLCSD and NSLCSD with statistical significance, no convective parameters related to the vertical wind shear can distinguish between the two categories. We evaluated the forecast skill of the convective parameters using Heidke Skill Score (HSS). The evaluation shows that the HSS for the Lifted Index and Precipitable Water are better among all parameters and have great forecast ability.
Yamane, Yusuke; Hayashi, Taiichi; Dewan, Ashraf Mahmmood; Akter, Fatima
Small chamber tests were conducted to experimentally determine the overall mass transfer coefficient for pollutant emissions from still water under simulated indoor-residential or occupational-environmental conditions. Fourteen tests were conducted in small environmental chambers...
Environmental and Geometrical Conditions to Sustain Crevice Corrosion in Alloy 22.
National Technical Information Service (NTIS)
Alloy 22 (N06022) is highly resistant to localized corrosion. Under aggressive environmental conditions Alloy 22 may be susceptible to crevice corrosion in hot chloride (Cl-) solutions. The objective of the present work was to explore the environmental an...
R. M. Carranza M. A. Rodriguez R. B. Rebak
The role of an alpha animal in changing environmental conditions.
The maintenance and development of conservation areas by grazing of large herbivores, such as Przewalski's horses, is common practice. Several nature conservation areas house male bachelor groups of this species. When males are needed for breeding they are removed from the groups, often without considering group compositions and individual social positions. However, alpha animals are needed for ensuring group stability and decision making in potentially dangerous situations in several species. To investigate the role of the alpha male in a bachelor group, we observed the behaviour of five Przewalski's horse males during the enlargement of their enclosure. We analyzed the group's social structure and movement orders, as well as the animals' connectedness, activity budgets, and whether they moved with preferred group members and how factors such as social rank influenced the horses' behaviour. We also investigated the excretion of glucocorticoid metabolites (GCM) via faeces of the horses while exploring a new area as a parameter of glucocorticoid production. Our results show that the alpha male is important for a bachelor group in changing environmental conditions. The alpha male had the highest level of connectedness within the group. When exploring the new environment, its position in the group changed from previously being the last to being the first. Furthermore the whole group behaviour changed when exploring the new area. The stallions showed reduced resting behavior, increased feeding and did not stay close to each other. We found that the excretion of glucocorticoid metabolites of most horses rose only marginally during the first days on the new area while only the alpha male showed a significant increased amount of glucocorticoid production during the first day of the enclosure enlargement. PMID:24878311
Wolter, Riccarda; Pantel, Norbert; Stefanski, Volker; MŲstl, Erich; Krueger, Konstanze
The integrity of a geomembrane installation is no better than its seaming system. In an attempt to learn more about the strength and durability of presently available seaming systems, the Municipal Environmental Research Laboratory of the United States Environmental Protection Ag...
Effects of simulated environmental conditions on glucocorticoid metabolite measurements in white-tailed deer feces
Environmental conditions may influence fecal glucocorticoid metabolite measurements if feces cannot be collected immediately after deposition. To evaluate the influence of environmental conditions on fecal glucocorticoid metabolite concentrations, we exposed fresh fecal samples to 1 of 5 simulated conditions: (1) room temperature (22įC), (2) high heat (38įC), (3) alternating high heat and room temperature cycle, (4) alternating freezing (?20įC) and
Brian E Washburn; Joshua J Millspaugh
Biological, physical, and chemical data were collected from surficial sediments of Lakes Ontario, Michigan, and Superior to examine benthic macroinvertebrate community structure as an indicator of environmental condition....
Investigation of the Effect of Music and Noise on a Prolonged Intellectual Task with Environmental Conditioning.
National Technical Information Service (NTIS)
The purpose of the research was to investigate the effect of music and noise on a prolonged intellectual task with environmental conditioning. A group of 46 subjects were administered algebra tests under nine treatment conditions consisting of two types o...
W. H. Nuckols
Effects of steady-state noise and temperature conditions on environmental perception and acceptability.
The combined effects of noise and temperature on environmental perception and acceptability were studied on 18 lightly clothed subjects (0.6 clo), individually exposed for 2 h in a climatic chamber. Three homogeneous climatic conditions were chosen (air temperature at 18, 24 or 30 degrees C, air velocity =0.1 m/s). For each of them, three different noise levels were continuously maintained (35, 60, 75 dBA, recorded fan noise). The 18 subjects were divided into three groups and each group experienced only one single thermal condition, at each level of noise, during three different experimental sessions. Subjective answers about perception and comfort were obtained at t = 30 and 120 min. Main results indicate that acoustic perception decreases when thermal environment is far from thermoneutrality. Although the combined effects of noise and temperature did not influence the physiological data, our results show that whatever the ambient temperature, thermal unpleasantness is higher when noise level increases. Finally, equivalence between acoustic and thermal sensations is proposed for short-term exposure (1 degree C = 2.6 dBA) and for steady state (1 degrees C = 2.9 dBA). In conclusion, this study strongly suggests that interactions between environmental components do exist, right from perceptual level, and might explain some combined effects on cognitive performance. PMID:15009419
Pellerin, N; Candas, V
Perceiving environmental properties from motion information: Minimal conditions
NASA Technical Reports Server (NTRS)
The status of motion as a minimal information source for perceiving the environmental properties of surface segregation, three-dimensional (3-D) form, displacement, and dynamics is discussed. The selection of these particular properties was motivated by a desire to present research on perceiving properties that span the range of dimensional complexity.
Proffitt, Dennis R.; Kaiser, Mary K.
Selection of Construction Methods Taking into Account Environmental Conditions.
National Technical Information Service (NTIS)
This research program aimed to look into and provide a comprehensive cross-sectional report on the environmental concerns affected by inner-urban building projects as well as their influence on the choice of construction methods used. The work starts off ...
H. G. Olshausen, J. Homes
Effect of environmental conditions on expansion in concrete due to alkaliĖsilica reaction (ASR)
The environmental conditions to which a concrete element incorporating alkaliĖsilica reactive aggregates is exposed play a major role in dictating the progression and manifestation of the reaction. This paper reports and analyses the results of research programs investigating the comparative evaluation of the effect of environmental conditions on the development of alkaliĖsilica reaction (ASR) in concrete specimens stored in outdoor
Benoit Fournier; Jason H. Ideker; Kevin J. Folliard; Michael D. A. Thomas; Pierre-Claver Nkinamubanzi; Ray Chevrier
Common lung conditions: environmental pollutants and lung disease.
Exposure to environmental pollutants can have short- and long-term effects on lung health. Sources of air pollution include gases (eg, carbon monoxide, ozone) and particulate matter (eg, soot, dust). In the United States, the Environmental Protection Agency regulates air pollution. Elevated ozone concentrations are associated with increases in lung-related hospitalizations and mortality. Elevated particulate matter pollution increases the risk of cardiopulmonary and lung cancer mortality. Occupations with high exposures to pollutants (eg, heavy construction work, truck driving, auto mechanics) pose higher risk of chronic obstructive lung disease. Some industrial settings (eg, agriculture, sawmills, meat packing plants) also are associated with higher risks from pollutants. The Environmental Protection Agency issues an air quality index for cities and regions in the United States. The upper levels on the index are associated with increases in asthma-related emergency department visits and hospitalizations. Damp and moldy housing might make asthma symptoms worse; individuals from lower socioeconomic groups who live in lower quality housing are particularly at risk. Other household exposures that can have negative effects on lung health include radon, nanoparticles, and biomass fuels. PMID:23767420
Delzell, John E
Effects of Environmental Conditions on Isoprene Emission from Live Oak.
National Technical Information Service (NTIS)
Live-oak plants (Quercus virginia) were subjected to various levels of CO2, water stress or photosynthetic photon flux density to test the hypothesis that isoprene biosynthesis occurred only under conditions of restricted CO2 availability. Isoprene emissi...
D. T. Tingey R. Evans M. Gumpertz
Environmental condition assessment of US military installations using GIS based spatial multi-criteria decision analysis.
Environment functions in various aspects including soil and water conservation, biodiversity and habitats, and landscape aesthetics. Comprehensive assessment of environmental condition is thus a great challenge. The issues include how to assess individual environmental components such as landscape aesthetics and integrate them into an indicator that can comprehensively quantify environmental condition. In this study, a geographic information systems based spatial multi-criteria decision analysis was used to integrate environmental variables and create the indicator. This approach was applied to Fort Riley Military installation in which land condition and its dynamics due to military training activities were assessed. The indicator was derived by integrating soil erosion, water quality, landscape fragmentation, landscape aesthetics, and noise based on the weights from the experts by assessing and ranking the environmental variables in terms of their importance. The results showed that landscape level indicator well quantified the overall environmental condition and its dynamics, while the indicator at level of patch that is defined as a homogeneous area that is different from its surroundings detailed the spatiotemporal variability of environmental condition. The environmental condition was mostly determined by soil erosion, then landscape fragmentation, water quality, landscape aesthetics, and noise. Overall, environmental condition at both landscape and patch levels greatly varied depending on the degree of ground and canopy disturbance and their spatial patterns due to military training activities and being related to slope. It was also determined the environment itself could be recovered quickly once military training was halt or reduced. Thus, this study provided an effective tool for the army land managers to monitor environmental dynamics and plan military training activities. Its limitation lies at that the obtained values of the indicator vary and are subjective to the experts' knowledge and experience. Thus, further advancing this approach is needed by developing a scientific method to derive the weights of environmental variables. PMID:22684636
Singer, Steve; Wang, Guangxing; Howard, Heidi; Anderson, Alan
Environmental Condition Assessment of US Military Installations Using GIS Based Spatial Multi-Criteria Decision Analysis
NASA Astrophysics Data System (ADS)
Environment functions in various aspects including soil and water conservation, biodiversity and habitats, and landscape aesthetics. Comprehensive assessment of environmental condition is thus a great challenge. The issues include how to assess individual environmental components such as landscape aesthetics and integrate them into an indicator that can comprehensively quantify environmental condition. In this study, a geographic information systems based spatial multi-criteria decision analysis was used to integrate environmental variables and create the indicator. This approach was applied to Fort Riley Military installation in which land condition and its dynamics due to military training activities were assessed. The indicator was derived by integrating soil erosion, water quality, landscape fragmentation, landscape aesthetics, and noise based on the weights from the experts by assessing and ranking the environmental variables in terms of their importance. The results showed that landscape level indicator well quantified the overall environmental condition and its dynamics, while the indicator at level of patch that is defined as a homogeneous area that is different from its surroundings detailed the spatiotemporal variability of environmental condition. The environmental condition was mostly determined by soil erosion, then landscape fragmentation, water quality, landscape aesthetics, and noise. Overall, environmental condition at both landscape and patch levels greatly varied depending on the degree of ground and canopy disturbance and their spatial patterns due to military training activities and being related to slope. It was also determined the environment itself could be recovered quickly once military training was halt or reduced. Thus, this study provided an effective tool for the army land managers to monitor environmental dynamics and plan military training activities. Its limitation lies at that the obtained values of the indicator vary and are subjective to the experts' knowledge and experience. Thus, further advancing this approach is needed by developing a scientific method to derive the weights of environmental variables.
Singer, Steve; Wang, Guangxing; Howard, Heidi; Anderson, Alan
Environmental conditions affect spatial genetic structures and dispersal patterns in a solitary rodent.
The study of the spatial distribution of relatives in a population under contrasted environmental conditions provides critical insights into the flexibility of dispersal behaviour and the role of environmental conditions in shaping population relatedness and social structure. Yet few studies have evaluated the effects of fluctuating environmental conditions on relatedness structure of solitary species in the wild. The aim of this study was to determine the impact of interannual variations in environmental conditions on the spatial distribution of relatives [spatial genetic structure (SGS)] and dispersal patterns of a wild population of eastern chipmunks (Tamias striatus), a solitary rodent of North America. Eastern chipmunks depend on the seed of masting trees for reproduction and survival. Here, we combined the analysis of the SGS of adults with direct estimates of juvenile dispersal distance during six contrasted years with different dispersal seasons, population sizes and seed production. We found that environmental conditions influences the dispersal distances of juveniles and that male juveniles dispersed farther than females. The extent of the SGS of adult females varied between years and matched the variation in environmental conditions. In contrast, the SGS of males did not vary between years. We also found a difference in SGS between males and females that was consistent with male-biased dispersal. This study suggests that both the dispersal behaviour and the relatedness structure in a population of a solitary species can be relatively labile and change according to environmental conditions. PMID:23017101
Messier, Gabrielle Dubuc; Garant, Dany; Bergeron, Patrick; Rťale, Denis
Live-oak plants (Quercus virginia) were subjected to various levels of CO2, water stress or photosynthetic photon flux density to test the hypothesis that isoprene biosynthesis occurred only under conditions of restricted CO2 availability. Isoprene emission increases as the ambie...
Vibration-based structural health monitoring using adaptive statistical method under varying environmental condition
NASA Astrophysics Data System (ADS)
It is well known that the dynamic properties of a structure such as natural frequencies depend not only on damage but also on environmental condition (e.g., temperature). The variation in dynamic characteristics of a structure due to environmental condition may mask damage of the structure. Without taking the change of environmental condition into account, false-positive or false-negative damage diagnosis may occur so that structural health monitoring becomes unreliable. In order to address this problem, an approach to construct a regression model based on structural responses considering environmental factors has been usually used by many researchers. The key to success of this approach is the formulation between the input and output variables of the regression model to take into account the environmental variations. However, it is quite challenging to determine proper environmental variables and measurement locations in advance for fully representing the relationship between the structural responses and the environmental variations. One alternative (i.e., novelty detection) is to remove the variations caused by environmental factors from the structural responses by using multivariate statistical analysis (e.g., principal component analysis (PCA), factor analysis, etc.). The success of this method is deeply depending on the accuracy of the description of normal condition. Generally, there is no prior information on normal condition during data acquisition, so that the normal condition is determined by subjective perspective with human-intervention. The proposed method is a novel adaptive multivariate statistical analysis for monitoring of structural damage detection under environmental change. One advantage of this method is the ability of a generative learning to capture the intrinsic characteristics of the normal condition. The proposed method is tested on numerically simulated data for a range of noise in measurement under environmental variation. A comparative study with conventional methods (i.e., fixed reference scheme) demonstrates the superior performance of the proposed method for structural damage detection.
Jin, Seung-Seop; Jung, Hyung-Jo
Effects of environmental conditions on isoprene emission from live oak
Live-oak plants (Quercus virginiana Mill.) were subjected to various levels of CO2, water stress or photosynthetic photon flux density to test the hypothesis that isoprene biosynthesis occurred only under conditions of restricted CO2 availability. Isoprene emission increases as the ambient CO2 concentration decreased, independent of the amount of time that plants had photosynthesized at ambient CO2 levels. When plants were
David T. Tingey; Rosemary Evans; Marcia Gumpertz
Age at menarche: the influence of environmental conditions
Age at menarche was studied by the recollection method in two groups of Causasian Jewish high school girls, inhabitants of two towns in Israel, Safad and Elat. The two towns differ mainly in climatic conditions. The age at menarche was found to be significantly lower (P<0.02) in the hot town of Elat than in the temperate town of Safad: 13.30Ī1.21
E. Saar; C. Shalev; I. Dalal; U. A. Sod-Moriah
Conclusive teleportation and entanglement concentration
Teleportation of a d-dimensional quantum state via a pure but partially entangled channel is studied. Two schemes are presented for conclusive teleportation aiming at both obtaining a faithful replica with optimal probability and achieving a maximum average fidelity of teleportation when conclusive teleportation fails. A single pair entanglement concentration scheme is also constructed.
Yong-Jian Gu; Yi-Zhuang Zheng; Guang-Can Guo
Using a Laboratory Conclusion Rubric
ERIC Educational Resources Information Center
Adding a strong conclusion can alter a cookbook lab into an inquiry lab by challenging the student to defend relevant data and clearly communicate his or her findings. A well-organized scoring guide makes it easier for students to understand what is involved in writing a strong conclusion. Examples of student writing that are accompanied with theÖ
Rutherford, Sandra
Alternative splicing and nonsense-mediated decay of circadian clock genes under environmental stress conditions in Arabidopsis
Background The circadian clock enables living organisms to anticipate recurring daily and seasonal fluctuations in their growth habitats and synchronize their biology to the environmental cycle. The plant circadian clock consists of multiple transcription-translation feedback loops that are entrained by environmental signals, such as light and temperature. In recent years, alternative splicing emerges as an important molecular mechanism that modulates the clock function in plants. Several clock genes are known to undergo alternative splicing in response to changes in environmental conditions, suggesting that the clock function is intimately associated with environmental responses via the alternative splicing of the clock genes. However, the alternative splicing events of the clock genes have not been studied at the molecular level. Results We systematically examined whether major clock genes undergo alternative splicing under various environmental conditions in Arabidopsis. We also investigated the fates of the RNA splice variants of the clock genes. It was found that the clock genes, including EARLY FLOWERING 3 (ELF3) and ZEITLUPE (ZTL) that have not been studied in terms of alternative splicing, undergo extensive alternative splicing through diverse modes of splicing events, such as intron retention, exon skipping, and selection of alternative 5? splice site. Their alternative splicing patterns were differentially influenced by changes in photoperiod, temperature extremes, and salt stress. Notably, the RNA splice variants of TIMING OF CAB EXPRESSION 1 (TOC1) and ELF3 were degraded through the nonsense-mediated decay (NMD) pathway, whereas those of other clock genes were insensitive to NMD. Conclusion Taken together, our observations demonstrate that the major clock genes examined undergo extensive alternative splicing under various environmental conditions, suggesting that alternative splicing is a molecular scheme that underlies the linkage between the clock and environmental stress adaptation in plants. It is also envisioned that alternative splicing of the clock genes plays more complex roles than previously expected.
Photodermatoses: environmentally induced conditions with high psychological impact.
Photodermatoses are a group of skin disorders caused or exacerbated by ultraviolet and/or visible radiation, which collectively affect a high proportion of the population and substantially affect quality of life (QoL). Our objective was to assess the psychological impact of these conditions. Patients with a range of photodermatoses diagnosed at a specialist investigation centre in the UK completed questionnaires evaluating (i) anxiety and (ii) depression, using the Hospital Anxiety and Depression Scale (HADS), (iii) social anxiety, using the Fear of Negative Evaluation measure (FNE), (iv) coping strategies (brief COPE) and (v) QoL, using the Dermatology Life Quality Index (DLQI). Questionnaires were returned by 185 of 260 patients (71.1% response rate). Mean age was 50.2 years (SD 14.5, range 20-85), 80.3% female. Polymorphic light eruption was the most common diagnosis, followed by photoaggravated eczema, other photoaggravated dermatological conditions and solar urticaria. Across the sample, high percentages, i.e. 23% and 7.9% of individuals, showed scores indicating clinical levels of anxiety and depression, respectively. Facial involvement was a strong indicator for depression (t = 2.7, p < 0.01). In regression analyses psychological factors (particularly depression and adaptive coping) were the principle predictors of QoL, accounting for 17.7% of the variance (F = 7.61, p < 0.01), while clinical variables accounted for an additional 10.1% (F = 8.96, p < 0.01), with number of months/year affected exerting a significant effect (p < 0.01). This study demonstrates the high psychological comorbidity of these conditions; more awareness of this is required, with adoption of a biopsychosocial approach to their management. PMID:22961505
Rizwan, Muneeza; Reddick, Charlotte Louise; Bundy, Christine; Unsworth, Rebecca; Richards, Helen Louise; Rhodes, Lesley Elizabeth
Exertional Heat Illness and Environmental Conditions During a Single Football Season in the Southeast
Context: Recommendations for heat illness prevention provided by sports medicine associations do not always account for sex differences, specific age populations, regional environmental conditions, equipment worn during activity, or the athlete's size or preexisting level of fitness. Objective: To evaluate the rate of exertional heat illness (EHI) among collegiate football athletes and to monitor environmental conditions during American football practice for a 3-month period. Design: Epidemiologic study in which we reviewed the occurrence rates of EHI and wet bulb globe temperature readings during a 3-month period of American collegiate football practice sessions. Setting: Five universities in the southeastern region of the United States. Patients or Other Participants: Collegiate football players at the 5 universities. Main Outcome Measure(s): Wet bulb globe temperatures were recorded from August through October 2003, at the beginning, middle, and end of each practice session. The EHIs were identified and recorded, and athlete-exposures (AEs) were calculated. Results: A total of 139 EHIs and 33?196 AEs were reported (EHI rate = 4.19/1000 AEs). The highest incidence of EHIs was in August (88%, EHI rate = 8.95/1000 AEs) and consisted of 70% heat cramps (6.13/1000 AEs), 23% heat exhaustion (2.06/ 1000 AEs), and 7% heat syncope (0.58/1000 AEs). No cases of heat stroke or hyponatremia were identified. The highest risk of EHI occurred during the first 3 weeks of the study; mean wet bulb globe temperature declined significantly as the study continued ( P < .001). Temperatures in the final 5 weeks of the study were significantly cooler than in the first 5 weeks ( P < .05). Conclusions: Heat cramps were the most common EHI and occurred most often during the first 3 weeks of practice. Athletic trainers should take all necessary preventive measures to reduce the risk of EHI.
Cooper, Earl R; Ferrara, Michael S; Broglio, Steven P
Using a Physical Education Environmental Survey to Identify Areas of Concern and Improve Conditions
ERIC Educational Resources Information Center
School environmental conditions can impact learning in physical educational classes. It is important for schools to control environmental health hazards, not only to promote a conducive school learning environment, but to also reduce associated health risks. To help physical education leaders determine the quality of physical education facilitiesÖ
Hill, Grant; Hulbert, George
Environmental stability control of the intensity of squall lines under low-level shear conditions
The environment for the development and evolution of linearly organized convective systems, i.e., squall lines is diverse for their existence in various climate regions. Understanding the behavior of squall lines under various environmental conditions is required for diagnosing and forecasting the development and intensity of the convective systems. The present study investigates the effects of environmental static stability on the
Tetsuya Takemi
Environmental Conditions in Northern Gulf of Mexico Estuaries: Before and After the Deepwater Horizon Oil Spill
When conducting an environmental assessment to determine the ecological effects of the Deepwater Horizon (DWH) Oil Spill in the Gulf of Mexico (GOM), baseline environmental data is essential to establish ecosystem condition prior to the incident. EPA?s National Coastal Assessment...
Behavior of Stressed and Unstressed 304L Specimens in Tuff Repository Environmental Conditions.
National Technical Information Service (NTIS)
This paper presents preliminary results of an investigation of the behavior of candidate barrier material for high-level nuclear waste storage, Type 304L stainless steel, in tuff repository environmental conditions. Tuff is a densely welded, devitrified, ...
M. C. Juhas R. D. McCright R. E. Garrison
Estimating environmental conditions of carbonate crystal fan formation
NASA Astrophysics Data System (ADS)
The sedimentary record reveals that the large-scale aspects of carbonate deposition have remained unchanged over > 3.4 Ga of Earth History. This reflects long term commonalities in the sources of DIC and alkalinity to seawater and the processes that generate and fill accommodation in sedimentary basins. Despite this stability, the record also reveals important first order changes in the nature of carbonate precipitation through time; this is documented in the decreasing abundance of sea floor carbonate precipitation. For example, carbonate crystal fans (large bladed crystals formed at the sediment-water interface, thought to be originally composed of aragonite) have a distinct distribution in time. They are common on Archean and Paleoproterozoic carbonate platforms and become rare by Neoproterozoic time, only reappearing during several unusual intervals (e.g. P-T mass extinction) in Phanerozoic basins. This has been interpreted as evidence for a decline in carbonate saturation through time. This pattern of distribution presents a fundamental problem. Despite being bathed in waters that are strongly supersaturated, direct precipitation of carbonate-bearing minerals on the sea floor is exceedingly rare in modern shallow tropical ocean basins. In order to examine this problem we examined processes controlling both the chemistry and physics of the sediment-water interface that could promote precipitation. Using a mathematical model to depict the influence of organic delivery and different microbial respiratory metabolisms on the carbonate chemistry within the shallow sediments, two non-unique chemical conditions emerge that indicate precipitation can be thermodynamically favorable on the seafloor from seawater with similar chemistry to todayís oceans. In agreement with modern porewater data, our results suggest that an important component inhibiting seafloor cementation is aerobic respiration in the shallow sediments. In addition to the chemical conditions of the interface, physical processes including high sedimentation rate, burrowing and seafloor agitation have the possibility of disrupting precipitation. We test hypotheses arising from our model results using geological observations of successions bearing crystal fans from the middle Ediacaran Rainstorm Member of the Johnnie Formation, Basin and Range, USA, and the Late Paleoproterozoic Rifle Formation, NW Territories Canada. By examining the accessory sediments associated with the cements from two specific examples from the record, quiescent periods with low background sedimentation rates emerge as important catalysts for growth. The accessory sediments associated with both examples are distinct from the surrounding sediments suggesting favorable conditions were not ever-present. Our analysis also shows that it is unlikely that all crystal fans result from a unique set of circumstances, rather there are several possible geobiological mechanisms that led to their deposition.
Bergmann, K. D.; Fischer, W. W.
Corrosion behavior of carbon steels under tuff repository environmental conditions
Carbon steels may be used for borehole liners in a potential high-level nuclear waste repository in tuff in Nevada. Borehole liners are needed to facilitate emplacement of the waste packages and to facilitate retrieval of the packages, if required. Corrosion rates of low carbon structural steels AISI 1020 and ASTM A-36 were determined in J-13 well water and in saturated steam at 100{sup 0}C. Tests were conducted in air-sparged J-13 water to attain more oxidizing conditions representative of irradiated aqueous environments. A limited number of irradiation corrosion and stress corrosion tests were performed. Chromium-molybdenum alloy steels and cast irons were also tested. These materials showed lower general corrosion but were susceptible to stress corrosion cracking when welded. 4 references, 4 tables.
McCright, R.D.; Weiss, H.
Rift Valley Fever outbreaks in Mauritania and related environmental conditions.
Four large outbreaks of Rift Valley Fever (RVF) occurred in Mauritania in 1998, 2003, 2010 and 2012 which caused lots of animal and several human deaths. We investigated rainfall and vegetation conditions that might have impacted on RVF transmission over the affected regions. Our results corroborate that RVF transmission generally occurs during the months of September and October in Mauritania, similarly to Senegal. The four outbreaks were preceded by a rainless period lasting at least a week followed by heavy precipitation that took place during the second half of the rainy season. First human infections were generally reported three to five weeks later. By bridging the gap between meteorological forecasting centers and veterinary services, an early warning system might be developed in Senegal and Mauritania to warn decision makers and health services about the upcoming RVF risk. PMID:24413703
Caminade, Cyril; Ndione, Jacques A; Diallo, Mawlouth; MacLeod, Dave A; Faye, Ousmane; Ba, Yamar; Dia, Ibrahima; Morse, Andrew P
Stability of Metabolic Correlations under Changing Environmental Conditions in Escherichia coli - A Systems Approach
Background Biological systems adapt to changing environments by reorganizing their cellular and physiological program with metabolites representing one important response level. Different stresses lead to both conserved and specific responses on the metabolite level which should be reflected in the underlying metabolic network. Methodology/Principal Findings Starting from experimental data obtained by a GC-MS based high-throughput metabolic profiling technology we here develop an approach that: (1) extracts network representations from metabolic condition-dependent data by using pairwise correlations, (2) determines the sets of stable and condition-dependent correlations based on a combination of statistical significance and homogeneity tests, and (3) can identify metabolites related to the stress response, which goes beyond simple observations about the changes of metabolic concentrations. The approach was tested with Escherichia coli as a model organism observed under four different environmental stress conditions (cold stress, heat stress, oxidative stress, lactose diauxie) and control unperturbed conditions. By constructing the stable network component, which displays a scale free topology and small-world characteristics, we demonstrated that: (1) metabolite hubs in this reconstructed correlation networks are significantly enriched for those contained in biochemical networks such as EcoCyc, (2) particular components of the stable network are enriched for functionally related biochemical pathways, and (3) independently of the response scale, based on their importance in the reorganization of the correlation network a set of metabolites can be identified which represent hypothetical candidates for adjusting to a stress-specific response. Conclusions/Significance Network-based tools allowed the identification of stress-dependent and general metabolic correlation networks. This correlation-network-based approach does not rely on major changes in concentration to identify metabolites important for stress adaptation, but rather on the changes in network properties with respect to metabolites. This should represent a useful complementary technique in addition to more classical approaches.
Nikoloski, Zoran; Selbig, Joachim; Nikiforova, Victoria; Catchpole, Gareth; Willmitzer, Lothar
Flexible DCP interface. [signal conditioning system for use with Kansas environmental sensors
NASA Technical Reports Server (NTRS)
The author has identified the following significant results. A user of an ERTS data collection system must supply the sensors and signal conditioning interface. The electronic interface must be compatible with the NASA-furnished data collection platform (DCP). A universal signal conditioning system for use with a wide range of environmental sensors is described. The interface is environmentally and electronically compatible with the DCP and has operated satisfactorily for a complete winter wheat growing season in Kansas.
Kanemasu, E. T. (principal investigator); Schimmelpfenning, H.
The U. S. Department of Energy (DOE) is studying Yucca Mountain as the possible site for a permanent underground repository for disposal of spent nuclear fuel (SNF) and other high-level waste (HLW). The emplacement of high-level radioactive waste in Yucca Mountain will release a large amount of heat into the rock above and below the repository. Due to this heat, the rock temperature will rise, and then decrease when the production of decay heat falls below the rate at which heat escapes from the hot zone. In addition to raising the rock temperature, the heat will vaporize water, which will condense in cooler regions. The condensate water may drain back toward the emplacement drifts or it may ''shed'' through the pillars between emplacement drifts. Other effects, such as coupled chemical and mechanical processes, may influence the movement of water above, within, and below the emplacement drifts. This study examined near field environmental parameters that could have an effect on the waste package, including temperature, humidity, seepage rate, pH of seepage, chemistry (dissolved salts/minerals) of seepage, composition of drift atmosphere, colloids, and biota. This report is a Type I analysis performed in support of the development of System Description Documents (SDDs). A Type I analysis is a quantitative or qualitative analysis that may fulfill any of a variety of purposes associated with the Monitored Geologic Repository (MGR), other than providing direct analytical support for design output documents. A Type I analysis may establish design input, as defined in the ''Quality Assurance Requirements and Description'' (QARD) (DOE 1998). This study establishes a technical basis for emplacement drift (i.e. at the waste package surface) environment criteria to be considered in the development of the waste package design. The information will support development of several SDDs and resolve emplacement drift external environment questions in the criteria of those documents. This study supports the following System Description Documents (SDDs): Uncanistered SNF Disposal Container, Canistered SNF Disposal Container, DHLW Disposal Container, DOE Waste Forms Disposal Container, Non-Fuel Components Disposal Container, Naval SNF Disposal Container and Ex-Container Systems development. Minimum and maximum bounding values for the parameters described in the scope of this study are established to support environment criteria development for those systems.
E. N. Lindner and E. F. Dembowski
The stability of collected human scent under various environmental conditions.
Human scent evidence collected from objects at a crime scene is used for scent discrimination with specially trained canines. Storage of the scent evidence is usually required yet no optimized storage protocol has been determined. Storage containers including glass, polyethylene, and aluminized pouches were evaluated to determine the optimal medium for storing human scent evidence of which glass was determined to be the optimal storage matrix. Hand odor samples were collected on three different sorbent materials, sealed in glass vials and subjected to different storage environments including room temperature, -80 degrees C conditions, dark storage, and UVA/UVB light exposure over a 7-week period. Volatile organic compounds (VOCs) in the headspace of the samples were extracted and identified using solid-phase micro-extraction-gas chromatography/mass spectrometry (SPME-GC/MS). Three-dimensional covariance mapping showed that glass containers subjected to minimal UVA/UVB light exposure provide the most stable environment for stored human scent samples. PMID:19737339
Hudson, Davia T; Curran, Allison M; Furton, Kenneth G
Integrated geographical assessment of environmental condition in water catchments: Linking landscape ecology, environmental modelling and GIS
Water catchments are functional geographical areas that integrate a variety of environmental processes and human impacts on landscapes. Integrated assessments recognize this interdependence of resources and components making up water catchments and are vital for viable long-term natural resource management. This paper couples eco-hydrological modelling with remote sensing, landscape ecological analyses and GIS to develop a series of indicators of
R Aspinall; D Pearson
Job Stress in the Nursing Profession: The Influence of Organizational and Environmental Conditions and Job Characteristics
The aim of the current study was to examine the influence of organizational and environmental work conditions on the job characteristics of nurses and on their health and well-being. The sample consisted of 807 registered nurses working in an academic hospital in Leiden (the Netherlands). The direct influence of work conditions on outcomes was examined. Mediation of job characteristics in
Tanya I. Gelsema; Margot van der Doef; Stan Maes; Simone Akerboom; Chris Verhoeven
Fruit production under different environmental and management conditions of argan, Argania spinosa (L.)
The studyís aim was to evaluate the effects of different management and environmental conditions on fruit and seed mass production of Argania spinosa, an endemic tree to Morocco that grows in arid and semiarid areas and is now undergoing a protracted regression due to overexploitation.Four study areas with different herbivory intensity, altitude and climatic conditions were selected. In each one
M. Zunzunegui; F. Ain-Lhout; J. JŠuregui; M. C. DŪaz Barradas; S. Boutaleb; L. Ńlvarez-Cansino; M. P. Esquivias
Ten-year variability in fluxes, meteorology, and environmental conditions at a Colorado subalpine forest site
NASA Astrophysics Data System (ADS)
Changing meteorological and environmental conditions affect fluxes; model analysis has shown that environmental variability directly accounts for about half the interannual variability in net ecosystem exchange (NEE) of CO2 whereas the other 50% is due to biotic responses to these changing variables (Richardson et al. 2007). In our study, ten years (1998-2008) of turbulent flux measurements of heat, water vapor, and CO2 at the Niwot Ridge AmeriFlux site (Monson et al. 2002) are examined with respect to meteorological conditions (atmospheric temperature, stability, precipitation, and cloudiness) as well as changes in environmental conditions, such as snow depth and soil moisture. The typical yearly cycle and an estimate of the magnitude of year-to-year variability in the diurnal fluxes and other variables for a high-elevation subalpine forest ecosystem are presented. Wintertime ecosystem respiration has an average 30-min NEE of 0.62 ?mol m-2 s-1 with an interannual range between 0.5-1 ?mol m-2 s-1. Uptake of CO2 in late summer has an average NEE of -0.71 ?mol m-2 s-1 with an interannual range between -0.1 to -1.5 ?mol m-2 s-1. Previous studies at the Niwot Ridge AmeriFlux site have described the importance of photosynthetic photon flux density (PPFD) (Monson et al. 2002) and also growing season length (Hu et al. 2009) on NEE. Water isotope ratios analyzed by Hu et al. (2009) have shown that trees at the site primarily rely on water from snowmelt to sustain them throughout the summer; combining this result with the SIPNET model, Hu et al. conclude that there is a limited connection between summer precipitation and the cumulative annual gross primary production (GPP). We have tested this conclusion more explicitly by examining the response of NEE to specific precipitation events and the effect of extended dry periods on the diel cycle of the fluxes, CO2 mole fraction, sap flow, and other meteorological and soil variables. Additionally, we examine the connection between seasonal changes in NEE to changes in CO2 mole fraction measured with a tunable diode laser at the site (Schaeffer et al. 2008). References: Hu, J., et al., 2009: Longer growing seasons lead to less carbon sequestration by a subalpine forest. Global Change Biology, doi:10.1111/j.1365-2486.2009.01967.x Monson, R. K., et al., 2002: Carbon sequestration in a high-elevation, subalpine forest. Global Change Biology, 8, 459-478. Richardson, A.D., et al., 2007: Environmental variation is directly responsible for short- but not long-term variation in forest-atmosphere carbon exchange. Global Change Biology, 13, 788-803. Schaeffer, S.M., et al., 2008: Long-term field performance of a tunable diode laser absorption spectrometer for analysis of carbon isotopes of CO2 in forest air. Atmospheric Chemistry and Physics, 8, 5263-5277.
Burns, S. P.; Turnipseed, A.; Bowling, D. R.; Hu, J.; Monson, R. K.
Characterizing the environmental conditions and estimating aboveground biomass productivity for switchgrass in the Great Plains, USA
NASA Astrophysics Data System (ADS)
Switchgrass is being evaluated as a potential feedstock source for cellulosic biofuels and is being cultivated in several regions of the United States. The recent availability of switchgrass land cover maps derived from the National Agricultural Statistics Service cropland data layer for the conterminous United States provides an opportunity to assess the environmental conditions of switchgrass over large areas and across different geographic locations. The main goal of this study is to investigate the relationship between site environmental conditions and switchgrass productivity and identify the optimal conditions for productive switchgrass in the Great Plains (GP). Environmental and climate variables such as elevation, soil organic carbon, available water capacity, climate, and seasonal weather were used in this study. Satellite-derived growing season averaged Normalized Difference Vegetation Index was used as a proxy for switchgrass productivity. The environmental conditions for switchgrass sites of variable productivity were summarized and a data-driven multiple regression switchgrass productivity model was developed. Results show that spring precipitation has the strongest correlation with switchgrass productivity (r = 0.92, 176 samples) and spring minimum temperature has the weakest correlation with switchgrass productivity (r = 0.16). An estimated switchgrass productivity map for the entire GP based on site environmental and climate conditions was generated. The estimated switchgrass biomass productivity map indicates that highly productive switchgrass areas are mainly located in the eastern part of the GP. Results from this study provide useful information for assessing economic feasibility or optimal land use decisions regarding switchgrass development in the GP.
Gu, Y.; Wylie, B. K.; Howard, D. M.
Environmental conditions modulate the switch among different states of the hydrophobin Vmh2 from Pleurotus ostreatus.
Fungal hydrophobins are amphipathic, highly surface-active, and self-assembling proteins. The class I hydrophobin Vmh2 from the basidiomycete fungus Pleurotus ostreatus seems to be the most hydrophobic hydrophobin characterized so far. Structural and functional properties of the protein as a function of the environmental conditions have been determined. At least three distinct phenomena can occur, being modulated by the environmental conditions: (1) when the pH increases or in the presence of Ca(2+) ions, an assembled state, ?-sheet rich, is formed; (2) when the solvent polarity increases, the protein shows an increased tendency to reach hydrophobic/hydrophilic interfaces, with no detectable conformational change; and (3) when a reversible conformational change and reversible aggregation occur at high temperature. Modulation of the Vmh2 conformational/aggregation features by changing the environmental conditions can be very useful in view of the potential protein applications. PMID:22292968
Longobardi, Sara; Picone, Delia; Ercole, Carmine; Spadaccini, Roberta; De Stefano, Luca; Rea, Ilaria; Giardina, Paola
A benthic index of environmental condition of Gulf of Mexico estuaries
An index was developed for estuarine macrobenthos in the Gulf of Mexico that discriminated between areas with degraded environmental\\u000a conditions and areas with undegraded or reference conditions. Test sites were identified as degraded or reference based on\\u000a criteria for dissolved oxygen levels, sediment toxicity tests, and sediment contamination. Discriminant analysis was used\\u000a to identify a suite of measures of benthic
Virginia D. Engle; J. Kevin Summers; Gary R. Gaston
Environmental consequences of impact cratering events as a function of ambient conditions on Earth.
The end of the Mesozoic Era is defined by a dramatic floral and faunal turnover that has been linked with the Chicxulub impact event, thus leading to the realization that impact cratering can affect both the geologic and biologic evolution of Earth. However, the environmental consequences of an impact event and any subsequent biological effects rely on several factors, including the ambient environmental conditions and the extant ecosystem structures at the time of impact. Some of the severest environmental perturbations of the Chicxulub impact event would not have been significant in some periods of Earth history. Consequently, the environmental and biological effects of an impact event must be evaluated in the context in which it occurs. PMID:12809133
Kring, David A
Defining life: synthesis and conclusions.
The first part of the paper offers philosophical landmarks on the general issue of defining life. Section 1 defends that the recognition of "life" has always been and remains primarily an intuitive process, for the scientist as for the layperson. However we should not expect, then, to be able to draw a definition from this original experience, because our cognitive apparatus has not been primarily designed for this. Section 2 is about definitions in general. Two kinds of definition should be carefully distinguished: lexical definitions (based upon current uses of a word), and stipulative or legislative definitions, which deliberately assign a meaning to a word, for the purpose of clarifying scientific or philosophical arguments. The present volume provides examples of these two kinds of definitions. Section 3 examines three traditional philosophical definitions of life, all of which have been elaborated prior to the emergence of biology as a specific scientific discipline: life as animation (Aristotle), life as mechanism, and life as organization (Kant). All three concepts constitute a common heritage that structures in depth a good deal of our cultural intuitions and vocabulary any time we try to think about "life". The present volume offers examples of these three concepts in contemporary scientific discourse. The second part of the paper proposes a synthesis of the major debates developed in this volume. Three major questions have been discussed. A first issue (Section 4) is whether we should define life or not, and why. Most authors are skeptical about the possibility of defining life in a strong way, although all admit that criteria are useful in contexts such as exobiology, artificial life and the origins of life. Section 5 examines the possible kinds of definitions of life presented in the volume. Those authors who have explicitly defended that a definition of life is needed, can be classified into two categories. The first category (or standard view) refers to two conditions: individual self-maintenance and the open-ended evolution of a collection of similar entities. The other category refuse to include reproduction and evolution, and take a sort of psychic view of the living. Section 6 examines the relationship between the question of the definition of life and that of the origins of life. There is a close parallel between the general conceptions of the origins of life and the definitions of life. PMID:20162362
Gayon, Jean
Defining Life: Synthesis and Conclusions
NASA Astrophysics Data System (ADS)
The first part of the paper offers philosophical landmarks on the general issue of defining life. ß1 defends that the recognition of ďlifeĒ has always been and remains primarily an intuitive process, for the scientist as for the layperson. However we should not expect, then, to be able to draw a definition from this original experience, because our cognitive apparatus has not been primarily designed for this. ß2 is about definitions in general. Two kinds of definition should be carefully distinguished: lexical definitions (based upon current uses of a word), and stipulative or legislative definitions, which deliberately assign a meaning to a word, for the purpose of clarifying scientific or philosophical arguments. The present volume provides examples of these two kinds of definitions. ß3 examines three traditional philosophical definitions of life, all of which have been elaborated prior to the emergence of biology as a specific scientific discipline: life as animation (Aristotle), life as mechanism, and life as organization (Kant). All three concepts constitute a common heritage that structures in depth a good deal of our cultural intuitions and vocabulary any time we try to think about ďlifeĒ. The present volume offers examples of these three concepts in contemporary scientific discourse. The second part of the paper proposes a synthesis of the major debates developed in this volume. Three major questions have been discussed. A first issue (ß4) is whether we should define life or not, and why. Most authors are skeptical about the possibility of defining life in a strong way, although all admit that criteria are useful in contexts such as exobiology, artificial life and the origins of life. ß5 examines the possible kinds of definitions of life presented in the volume. Those authors who have explicitly defended that a definition of life is needed, can be classified into two categories. The first category (or standard view) refers to two conditions: individual self-maintenance and the open-ended evolution of a collection of similar entities. The other category refuse to include reproduction and evolution, and take a sort of psychic view of the living. ß6 examines the relationship between the question of the definition of life and that of the origins of life. There is a close parallel between the general conceptions of the origins of life and the definitions of life.
Gayon, Jean
Annual production of estuarine fauna in different environmental conditions: An evaluation of the estimation methods
Secondary production is one of the most comprehensive measurements of ecosystem health. Production of five estuarine species, with different life history and abundance in the ecosystem, was estimated for 2 consecutive years at a Zostera noltii bed and sand-muddy area, with contrasted environmental conditions. Calculations were performed using different estimation methods, commonly cited in secondary production studies. Annual production estimated
M. Dolbeth; A. I. LillebÝ; P. G. Cardoso; S. M. Ferreira; M. A. Pardal
Influence of Environmental Conditions on Methanogenic Compositions in Anaerobic Biogas Reactors
The influence of environmental parameters on the diversity of methanogenic communities in 15 full-scale biogas plants operating under different conditions with either manure or sludge as feedstock was studied. Fluorescence in situ hybridization was used to identify dominant methanogenic members of the Archaea in the reactor samples; enriched and pure cultures were used to support the in situ identification. Dominance
Dimitar Karakashev; Damien J. Batstone; Irini Angelidaki
Vegetation and environmental conditions in recently restored wetlands in the prairie pothole region of the USA
How closely the vegetation of restored wetlands resembles that of comparable natural wetlands is a function of the probability of propagules of wetland species reaching reflooded wetlands and how similar environmental conditions in the restored wetland are those in the natural wetlands. Three years after reflooding, we examined the vegetation composition, water level fluctuations, soil organic carbon content, and soil
Susan M. Galatowitsch; Arnold G. van der Valk
The transactional psychobiological nature of cognitive appraisal during exercise in environmentally stressful conditions
Background and Purpose: Successful adaptation to the stress of physical exertion in adverse environmental conditions (heat, cold, high altitude) is of great concern when optimal performance within safe parameters is the goal. The perception of the psychophysical demands imposed by the stressful situation and the perceived capability to cope with these demands is a process that can dramatically alter the
Edmund O. Acevedo; Panteleimon Ekkekakis
Environmental conditions and structure of the West African and Eastern Tropical Atlantic squall lines
The environmental conditions in advance of three West African disturbance lines and three Eastern Atlantic squall lines are examined as is the modification of the environment during the passage of such storms over a site. A comparison with other tropical squall lines observed over Venezuela is made. A model of the relative airflow within a West African disturbance line is
W. Fernandez
Dietary CDP-Choline Supplementation Prevents Memory Impairment Caused by Impoverished Environmental Conditions in Rats
ERIC Educational Resources Information Center
The authors previously showed that dietary cytidine (5')-diphosphocholine (CDP-choline) supplementation could protect against the development of memory deficits in aging rats. In the present study, younger rats exposed to impoverished environmental conditions and manifesting hippocampal-dependent memory impairments similar to those observed in theÖ
Teather, Lisa A.; Wurtman, Richard J.
Survey of Environmental Conditions Relative to Display of Photographs in Consumer Homes
The long-term stability of inkjet photographic prints is known to be sensitive to a variety of factors. The chemical composition of the inks (pigments vs dyes) and media (porous vs swellable), as well as the ambient environmental conditions (light, heat, humidity, air quality) under which the prints are stored and\\/or displayed, are known to affect image stability. In order to
Douglas Bugner; Joseph LaBarca; David Kopperl; Jonathan Phillips; David Skye; Irene Baker; Caryn Cunningham; Paige Miller; Thomas Kaltenbach
Environmental conditions to achieve low adhesion and low friction on diamond surfaces
The adhesion and friction of both diamond and diamond-like carbon coatings can be dramatically changed by active gases in the environment, such as hydrogen, water vapor and humid air, due to tribochemical reactions. To understand the atmospheric effects and to predict the optimized environmental conditions (gas species, pressure and temperature), the tribochemical reactions on diamond surfaces are modeled from first
Haibo Guo; Yue Qi
Optimization of Environmental Conditions to Maximize Carbon Dioxide Sequestration Through Algal Growth.
National Technical Information Service (NTIS)
The micro-alga Chlorella vulgaris was cultivated under a variety of environmental conditions in various culture media solutions to optimize growth rate and biomass productivity. Efforts during this work investigated growth at the micro-scale in an air-lif...
K. M. Karcher
Assessing Solar PV Behavior Under Varying Environmental Conditions - A Statistical approach
Accurate prediction of solar PV cell and module behaviour under actual environmental conditions of the application site and selection of the best performing module out of available alternatives is a big challenge for guaranteed payback and reliable operation of any solar PV energy project. The authors have come out with a quick yet reliable methodology for this purpose using quality
D. Paul; D. Mukherjee; S. R. Bhadra Chaudhuri
Environmental Control System Installer/Servicer (Residential Air Conditioning Mechanic). V-TECS Guide.
ERIC Educational Resources Information Center
This guide provides job relevant tasks, performance objectives, performance guides, resources, learning activitites, evaluation standards, and achievement testing in the occupation of environmental control system installer/servicer (residential air conditioning mechanic). It is designed to be used with any chosen teaching method. The courseÖ
Meyer, Calvin F.; Benson, Robert T.
The influence of environmental conditions on aspects of the time budgests of breeding ospreys
Ospreys (Pandion haliaetus) were observed for 350 h in 1975 in southeastern Virginia. Other studies have demonstrated that weather can have an effect on aspects of osprey foraging behavior (e.g., frequency of diving), but for the environmental conditions observed in this study, weather and other variables did not appear to limit the ability of ospreys to feed their young.
Christopher H. Stinson
A total of 254 pull-off tests were carried out to investigate the influence of different environmental conditions on the bond strength between the concrete and 4 types of carbon fiber reinforced polymers (CFRP) and 3 types of glass FRP (GFRP) sheets. Each type of FRP sheet was epoxide on the concrete surface as per the recommendations of its manufacturer. Tests
Saleh H. Alsayed; Tarek H. Almusallam
Evaluation of stability and adaptability for new spring safflower lines in different environmental conditions of Iran
The stability of seven spring safflower cultivars and lines were evaluated in five different environmental conditions of Karaj, Isfahan, Eslamabad, and Zargan, in Iran, for two years (2002- 2004). Simple analysis of variances of grain and oil yields from each experiment showed significant differences among the genotypes. After having homogeneity test for error variances combined analysis of variance was performed.
A. H. Omidi
Examples of landscape indicators for assessing environmental conditions and problems in urban and suburban areas
Geo-indicators can help to assess environmental conditions in city urban and suburban areas. Those indicators should be meaningful for understanding environmental changes. From examples of Spanish and American cities, geo-indicators for assessing environmental conditions and changes in urban and suburban areas are proposed. The paper explore two types of geo-indicators. The first type presents general information that can be used to indicate the presence of a broad array of geologic conditions, either favouring or limiting various kinds of uses of the land. The second type of geo-indicator is the one most commonly used, and as a group most easily understood; these are site and problem specific and they are generally used after a problem is identified. Among them, watershed processes, seismicity and physiographic diversity are explained in more detail. A second dimension that is considered when discussing geo-indicators is the issue of scale. Broad scale investigations, covering extensive areas are only efficient at cataloguing general conditions common to much of the area or some outstanding feature within the area. This type of information is best used for policy type decisions. Detailed scale investigations can provide information about local conditions, but are not efficient at cataloguing vast areas. Information gathered at the detailed level is necessary for project design and construction.
Martin-Duque, J. F.; Godfrey, A.; Diez, A.; Cleaves, E.; Pedraza, J.; Sanz, M. A.; Carrasco, R. M.; Bodoque, J.
Effect of environmental conditions on the fatty acid fingerprint of microbial communities
NASA Astrophysics Data System (ADS)
Lipid biomarkers, especially phospholipids, are routinely used to characterize microbial community structure in environmental samples. Interpretations of these fingerprints mainly depend on rare results of pure cultures which were cultivated under standardized batch conditions. However, membrane lipids (e.g. phopholipid biomarker) build up the interface between microorganisms and their environment and consequently are prone to be adapted according to the environmental conditions. We cultivated several bacteria, isolated from soil (gram-positive and gram-negative) under various conditions e.g. C supply and temperature regimes. Effect of growth conditions on phospholipids fatty acid (PLFA) as well as neutral lipid fatty acids (NLFA) and glycolipid fatty acids (GLFA) was investigated by conventional method of extraction and derivatization, followed by assessments with gas chromatography mass spectrometry (GC-MS). In addition, phospholipids were measured as intact molecules by ultra high performance liquid chromatography - quadrupole - time of flight mass spectrometer (UHPLC-Q-ToF) to further assess the composition of headgroups with fatty acids residues and their response on changing environmental conditions. PLFA fingerprints revealed a strong effect of growth stage, C supply and temperature e.g. decrease of temperature increased the amount of branched and/or unsaturated fatty acids to maintain the membrane fluidity. This strongly changes the ratio of specific to unspecific fatty acids depending on environmental conditions. Therefore, amounts of specific fatty acids cannot be used to assess biomass of a functional microbial group in soil. Intracellular neutral lipids depended less on environmental conditions reflecting a more stable biomarker group but also showed less specific fatty acids then PLFA. Therefore, combination of several lipid classes is suggested as more powerful tool to assess amounts and functionality of environmental microbial communities. Further information was gained from the analysis of intact polar lipids. Ethanolamines and cholines were the most abundant head groups within bacteria and are mainly combined with one specific and one unspecific fatty acid. Reactions on changing environmental conditions occurred mainly by modifications of fatty acids and rarely by a change of the headgroup fingerprint. This approach thus enables to categorize a certain amount of formerly unspecific fatty acids towards a specific microbial group. Ecological understanding for the interface between surrounding environment and cellular metabolism could be deepened by investigating the intact compounds e.g. intact phospholipids of microbial membranes. However, data from further organisms as well as diverse microbial communities are needed to continue the databases of intact phospholipids. Further investigations of diverse microbial communities under changing environmental conditions have to follow these first studies to 1) assess the effects of soil environment on microbial membranes (e.g. associations in biofilms) and 2) assess the effect of interspecific microbial interactions on their membrane properties and lipid fingerprints. Thus, combination of various lipid biomarkers as well as their intact characterization enables a more detailed look into microbial community structure and their respond on environmental conditions, improves our understanding of microbial functioning in ecosystems and enables a more specific estimation of biomass of various microbial groups.
Biryukov, Mikhail; Dippold, Michaela; Kuzyakov, Yakov
Assessment of the environmental conditions of the Sarno river basin (south Italy): a stream sediment approach.
The Sarno river basin covers an area of 500 km(2) collecting the waters of Solofrana and Cavaiola tributaries. Originally it manly represents a source of livelihood for inhabitants by fishing and transporting goods; currently, the Sarno river, still partially used for irrigation, is affected by an extreme environmental degradation as a result of uncontrolled outflow of industrial waste. Within the framework of a wider geochemical prospecting project aiming at characterizing the whole territory of the Campania region, 89 stream sediment samples with a sampling density of 1 sample per 5 km(2) were collected in the river basin and analyzed by means of inductively coupled plasma-mass spectrometry in order to assess the environmental conditions at a regional scale. A GIS-aided technique, based on both the actual distribution of potentially harmful elements and their regional background values, was used to generate the maps of the contamination factors and of the contamination degrees for As, Cd, Cr, Cu, Hg, Pb and Zn. Furthermore, a factor analysis was performed to assess the nature and the extent of contamination sources for the river sediments. Results showed that the Sarno river basin could be divided in two "environmental status" units: one, low contaminated, corresponding to the hilly and mountain areas, and the second, from moderately to very highly contaminated, corresponding to the economically developed areas of the valley floor characterized by a high population density. This work was developed within a project that aims to investigate the relationships between environmental pollution and human health by analyzing environmental media (stream sediments, water, soil and vegetation) together with human hair of resident population. In this context, the spatial correlation between the extremely compromised environmental conditions of developed areas and the incidence rate of liver cancer in the same area was also explored posing the need of a careful costs/benefits analysis to assess whether the deterioration of the environment, that could adversely affect the conditions of public health, is worth the economic development. PMID:23053925
Albanese, Stefano; Iavazzo, Pietro; Adamo, Paola; Lima, Annamaria; De Vivo, Benedetto
A new insight into the contribution of environmental conditions to tropical cyclone activities
NASA Astrophysics Data System (ADS)
The changes of tropical cyclone (TC) activities in response to influencing environmental conditions have been paid more and more attention to in recent years. The potential contributions of single and multivariate environmental variables to annual TC frequency and intensity from 1970 to 2009 are investigated in this study. Instead of using correlation coefficient that assumes a set of samples satisfying the normal distribution, a quantitative measurement is formulated based on the information theory. The results show that dynamic environmental variables play an important role in variations of TC activities over the western North Pacific, North Atlantic, and eastern Pacific. These dynamic factors include wind shear between 850 and 200 hPa and 850-hPa relative vorticity. However, the effects of thermal factors on TC activities are distinct over different basins. The thermal environmental variables only have significant contributions to TC frequency and intensity over the eastern Pacific as well as to TC frequency over the North Atlantic. It is found that the primary factors influencing TC activities are indeed not the same over different basins because of the differences in atmospheric conditions and their changes across different areas. The effects of dynamic variables should be considered more in the regions such as the western North Pacific where the thermal conditions are always satisfied.
Wang, Yuan; Song, Jinjie; Wu, Rongsheng
Behavior of stressed and unstressed 304L specimens in tuff repository environmental conditions
This paper presents preliminary results of an investigation of the behavior of candidate barrier material for high-level nuclear waste storage, Type 304L stainless steel, in tuff repository environmental conditions. Tuff is a densely welded, devitrified, igneous rock common to the proposed repository site at Yucca Mountain, Nevada. The results discussed include: irradiation corrosion tests, U-bend irradiation corrosion tests, slow strain rate tests, and bent beam stress corrosion tests. Results indicate that Type 304L stainless steel shows excellent resistance to general, localized, and stress corrosion under the environmental and microstructural conditions tested so far. The environmental test conditions are 50 to 100{sup 0}C J-13 well water (non-saline, near neutral pH, and oxic in nature) and saturated steam at 100{sup 0}C. Microstructural conditions include solution annealed and long furnace heat treatments to provoke a sensitized structure. However, this particular type of stainless steel may be susceptible to long-term, low-temperature sensitization because of the combination of expected time at elevated temperature and residual stress in the container after emplacement in the repository. Other grades of austenitic stainless steels are reported to be more resistant to low-temperature sensitization. Future work will therefore include more extensive testing of these grades. 15 references, 5 figures, 7 tables.
Juhas, M.C.; McCright, R.D.; Garrison, R.E.
Accounting for Variable Environmental Conditions in Time-Lapse Electrical Resistivity Images
NASA Astrophysics Data System (ADS)
Time-lapse electrical resistivity imaging (ERI) is being used to monitor salt transport at a remediation site in Alberta, Canada. The goal is to use ERI to produce images of salt concentration in soil. Mapping the salt concentration is possible because soil electrical conductivity (EC) is strongly correlated with salt concentration. However, soil EC is also affected by the temperature of the soil and the soil moisture content. Temperature and soil moisture conditions vary with changing environmental conditions. Three-D ERI results show that dramatically incorrect interpretations will result by neglecting differences in environmental conditions at the time of surveys. These results have two important implications 1) the petrophysical relationship that maps ERI values to salt concentration must be applied to images that have been converted to a standard condition equivalent EC value, and 2) auxiliary field measurements are required to establish temperature and saturation profiles at the time of surveys. We have chosen to standardize our images to 6 Deg. C and saturation of 1 because these values are most representative of the average conditions at the site. Laboratory measurements show that the temperature correction is 3.0% EC per Deg. C. The Waxman-Smits equation is used to correct for saturation differences. Finally, laboratory measurements have established an empirical relationship between soil EC at standard conditions and the regulatory measure of soil paste EC.
Bentley, L. R.; Gharibi, M.; Hayley, K.
A chamber to test the response of radon detectors to changing environmental conditions.
Radon risk assessment is carried out by means of accurate measurements with active or passive instrumentation. All radon detectors must be calibrated and tested using a radon chamber containing a known concentration of radon produced by specific sources of (226)Ra. Some chambers can also be used to test the response of detectors as a function of environmental conditions. In this case, a calibration curve can be inferred with respect to change in one of the considered parameters. For this aim, a new radon chamber was designed and realised to perform calibration and to study the detector response in a large range of variation of the environmental parameters (pressure, 700-1100 mbar; temperature, 5-50įC; humidity, 10-90 %). The first experiments conducted to study the influence of environmental parameters on the detector response have shown flexibility and ease of use of the chamber. PMID:21486825
Compagno, A; Parlato, A; Rizzo, S; Tomarchio, E
Immune Activity, Body Condition and Human-Associated Environmental Impacts in a Wild Marine Mammal
Within individuals, immunity may compete with other life history traits for resources, such as energy and protein, and the damage caused by immunopathology can sometimes outweigh the protective benefits that immune responses confer. However, our understanding of the costs of immunity in the wild and how they relate to the myriad energetic demands on free-ranging organisms is limited. The endangered Galapagos sea lion (Zalophus wollebaeki) is threatened simultaneously by disease from domestic animals and rapid changes in food availability driven by unpredictable environmental variation. We made use of this unique ecology to investigate the relationship between changes in immune activity and changes in body condition. We found that during the first three months of life, changes in antibody concentration were negatively correlated with changes in mass per unit length, skinfold thickness and serum albumin concentration, but only in a sea lion colony exposed to anthropogenic environmental impacts. It has previously been shown that changes in antibody concentration during early Galapagos sea lion development were higher in a colony exposed to anthropogenic environmental impacts than in a control colony. This study allows for the possibility that these relatively large changes in antibody concentration are associated with negative impacts on fitness through an effect on body condition. Our findings suggest that energy availability and the degree of plasticity in immune investment may influence disease risk in natural populations synergistically, through a trade-off between investment in immunity and resistance to starvation. The relative benefits of such investments may change quickly and unpredictably, which allows for the possibility that individuals fine-tune their investment strategies in response to changes in environmental conditions. In addition, our results suggest that anthropogenic environmental impacts may impose subtle energetic costs on individuals, which could contribute to population declines, especially in times of energy shortage.
Brock, Patrick M.; Hall, Ailsa J.; Goodman, Simon J.; Cruz, Marilyn; Acevedo-Whitehouse, Karina
The hidden function of photosynthesis: a sensing system for environmental conditions that regulates plant acclimation responses.
Plants convert light energy from the sun into chemical energy by photosynthesis. Since they are sessile, they have to deal with a wide range of conditions in their immediate environment. Many abiotic and biotic parameters exhibit considerable fluctuations which can have detrimental effects especially on the efficiency of photosynthetic light harvesting. During evolution, plants, therefore, evolved a number of acclimation processes which help them to adapt photosynthesis to such environmental changes. This includes protective mechanisms such as excess energy dissipation and processes supporting energy redistribution, e.g. state transitions or photosystem stoichiometry adjustment. Intriguingly, all these responses are triggered by photosynthesis itself via the interplay of its light reaction and the Calvin-Benson cycle with the residing environmental condition. Thus, besides its primary function in harnessing and converting light energy, photosynthesis acts as a sensing system for environmental changes that controls molecular acclimation responses which adapt the photosynthetic function to the environmental change. Important signalling parameters directly or indirectly affected by the environment are the pH gradient across the thylakoid membrane and the redox states of components of the photosynthetic electron transport chain and/or electron end acceptors coupled to it. Recent advances demonstrate that these signals control post-translational modifications of the photosynthetic protein complexes and also affect plastid and nuclear gene expression machineries as well as metabolic pathways providing a regulatory framework for an integrated response of the plant to the environment at all cellular levels. PMID:22441589
Pfannschmidt, Thomas; Yang, Chunhong
Environmental Conditions Influence Allometric Patterns in the Blow Fly, Chrysomya albiceps
The objective of this research was to study variations in allometry of body characters in females and males of two populations of blow flies, Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae), under different environmental conditions to establish patterns of morphological variation. Body size of both males and females in the experimental population was significantly higher than in the individuals of the natural population, indicating an important influence of food on body size. All genitalic and non-genitalic characters in males and females of the two populations showed a trend towards negative allometry rather than isometry. Allometric patterns were modified in both sexes and between populations. The data show generally larger allometric slopes in females than in males. We confirmed that the environmental conditions have an important effect on allometric patterns and body size.
Horenstein, M Battan; Peretti, Av
Iodine isotopes species fingerprinting environmental conditions in surface water along the northeastern Atlantic Ocean
Concentrations and species of iodine isotopes (127I and 129I) provide vital information about iodine geochemistry, environmental conditions and water masses exchange in oceans. Despite extensive investigations of anthropogenic 129I in the Arctic Ocean and the Nordic Seas, concentrations of the isotope in the Atlantic Ocean are, however, still unknown. We here present first data on 129I and 127I, and their species (iodide and iodate) in surface water transect along the northeastern Atlantic between 30į and 50įN. The results show iodate as the predominant species in the analyzed marine waters for both 127I and 129I. Despite the rather constant ratios of 127I?/127IO3?, the 129I?/129IO3? values reveal variations that apparently response to sources, environmental conditions and residence time. These findings provide a new tracer approach that will strongly enhance the application of anthropogenic 129I in ocean environments and impact on climate at the ocean boundary layer.
He, Peng; Hou, Xiaolin; Aldahan, Ala; Possnert, Goran; Yi, Peng
Iodine isotopes species fingerprinting environmental conditions in surface water along the northeastern Atlantic Ocean.
Concentrations and species of iodine isotopes ((127)I and (129)I) provide vital information about iodine geochemistry, environmental conditions and water masses exchange in oceans. Despite extensive investigations of anthropogenic (129)I in the Arctic Ocean and the Nordic Seas, concentrations of the isotope in the Atlantic Ocean are, however, still unknown. We here present first data on (129)I and (127)I, and their species (iodide and iodate) in surface water transect along the northeastern Atlantic between 30į and 50įN. The results show iodate as the predominant species in the analyzed marine waters for both (127)I and (129)I. Despite the rather constant ratios of (127)I(-)/(127)IO3(-), the (129)I(-)/(129)IO3(-) values reveal variations that apparently response to sources, environmental conditions and residence time. These findings provide a new tracer approach that will strongly enhance the application of anthropogenic (129)I in ocean environments and impact on climate at the ocean boundary layer. PMID:24284916
He, Peng; Hou, Xiaolin; Aldahan, Ala; Possnert, GŲran; Yi, Peng
Environmental conditions influence allometric patterns in the blow fly, Chrysomya albiceps.
The objective of this research was to study variations in allometry of body characters in females and males of two populations of blow flies, Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae), under different environmental conditions to establish patterns of morphological variation. Body size of both males and females in the experimental population was significantly higher than in the individuals of the natural population, indicating an important influence of food on body size. All genitalic and non-genitalic characters in males and females of the two populations showed a trend towards negative allometry rather than isometry. Allometric patterns were modified in both sexes and between populations. The data show generally larger allometric slopes in females than in males. We confirmed that the environmental conditions have an important effect on allometric patterns and body size. PMID:22224467
Horenstein, M BattŠn; Peretti, A V
Iodine isotopes species fingerprinting environmental conditions in surface water along the northeastern Atlantic Ocean
NASA Astrophysics Data System (ADS)
Concentrations and species of iodine isotopes (127I and 129I) provide vital information about iodine geochemistry, environmental conditions and water masses exchange in oceans. Despite extensive investigations of anthropogenic 129I in the Arctic Ocean and the Nordic Seas, concentrations of the isotope in the Atlantic Ocean are, however, still unknown. We here present first data on 129I and 127I, and their species (iodide and iodate) in surface water transect along the northeastern Atlantic between 30į and 50įN. The results show iodate as the predominant species in the analyzed marine waters for both 127I and 129I. Despite the rather constant ratios of 127I-/127IO3-, the 129I-/129IO3- values reveal variations that apparently response to sources, environmental conditions and residence time. These findings provide a new tracer approach that will strongly enhance the application of anthropogenic 129I in ocean environments and impact on climate at the ocean boundary layer.
He, Peng; Hou, Xiaolin; Aldahan, Ala; Possnert, GŲran; Yi, Peng
Food web expansion and contraction in response to changing environmental conditions.
Macroscopic ecosystem properties, such as major material pathways and community biomass structure, underlie the ecosystem services on which humans rely. While ecologists have long sought to identify the determinants of the trophic height of food webs (food chain length), it is somewhat surprising how little research effort is invested in understanding changes among other food web properties across environmental conditions. Here we theoretically and empirically show how a suite of fundamental macroscopic food web structures respond, in concert, to changes in habitat accessibility using post-glacial lakes as model ecosystems. We argue that as resource accessibility increases in coupled food webs, food chain length contracts (that is, reduced predator trophic position), habitat coupling expands (that is, increasingly coupled macrohabitats) and biomass pyramid structure becomes more top heavy. Our results further support an emerging theoretical view of flexible food webs that provides a foundation for generally understanding ecosystem responses to changing environmental conditions. PMID:23033081
Tunney, Tyler D; McCann, Kevin S; Lester, Nigel P; Shuter, Brian J
Influence of Increased Environmental Complexity on Leg Condition, Performance, and Level of Fearfulness in Broilers
We hypothesized that increased distance between resources and stimulation of foraging behavior, through altering the degree of environmental complexity by using moving lights and scattering whole wheat in the litter, would improve physical activity of broiler chickens. Increased activity may potentially improve leg condition and performance and decrease the level of fearfulness in broilers. To test this hypothesis, 1,800 1-d-old
D. Bizeray; I. Estevez; C. Leterrier; J. M. Faure
Biodegradation of agro-industrial orange waste under solid state fermentation and natural environmental conditions
Evaluation of the possibility of the re-use of agro-industrial orange peel and pulp wastes under solid state fermentation and natural environmental condition as a source of enzymes production (? & ? amylase, cellulase, pectinase(s), lipase(s), esterase(s) and peroxidase(s)) the physiological enzymes of lysis and total protein. Different microorganisms such as fungi, bacteria and yeast which were charged of waste analyse
Shahera H. Attyia; Sanaa M. Ashour
Comparison of soil and other environmental conditions in constructed and adjacent palustrine reference wetlands
Wetlands are created to compensate for the loss of natural wetlands as a result of human landuse activities. How well these\\u000a constructed wetlands mimic natural wetlands is in debate. The goal of this study was to compare soil and other environmental\\u000a conditions within constructed and adjacent reference wetlands to assess the progress of the constructed wetlands towards a\\u000a functional wetland.
Mark H. Stolt; Michael H. Genthner; W. Lee Daniels; Velva A. Groover; Steven Nagle; Katie C. Haering
Response of maize and rice to 9-?-L(+) adenosine applied under different environmental conditions
The increase in growth, determined by dry weight gain, of rice (Oryza sativa L.) and maize (Zea mays L.) caused by foliar applications of 9-Ŗ-L(+) adenosine, a putative second messenger elicited by triacontanol, was studied under different environmental conditions. Maize seedlings cultured in the greenhouse under approximately 100 Ķmol m-2s-1 of light prior to treatment with L(+) adenosine did not
Stanley Ries; Violet Wert
Dichromated pullulan diffraction gratings: influence of environmental conditions and storage time on their properties
NASA Astrophysics Data System (ADS)
Investigations of the environmental stability of diffraction gratings, recorded in dichromated pullulan (DCP), are reported. Profile changes of DCP surface relief gratings, under high humidity conditions, were analyzed using an atomic force microscope. It was found that the profile was not altered, while the diffraction efficiency was preserved. The influence of storage life on the diffraction efficiency and surface profile of DCP gratings were also investigated. It was concluded that DCP gratings offer much better stability compared with the dichromated gelatin.
Savi? äevi?, Svetlana; Panteli?, Dejan
Effect of environmental conditions on biological decolorization of textile dyestuff by C. versicolor
Effects of environmental conditions such as pH, media composition, carbon and nitrogen sources, TOC\\/N ratio, and dyestuff concentrations on decolorization of reactive phytalocyanin type textile dyestuff Everzol Turquoise Blue G by white rot fungi, Coriolus versicolor MUCL were investigated. pH = 4.5 and the media III were found to be the most suitable ones among the others tested. Compared to
Ilgi Karapinar Kapdan; Fikret Kargia; Geoffrey McMullan; Roger Marchant
Behavior of stressed and unstressed 304L specimens in tuff repository environmental conditions
This paper presents preliminary results of an investigation of the behavior of candidate barrier material for high-level nuclear waste storage, Type 304L stainless steel, in tuff repository environmental conditions. Tuff is a densely welded, devitrified, igneous rock common to the proposed repository site at Yucca Mountain, Nevada. The results discussed include: irradiation corrosion tests, U-bend irradiation corrosion tests, slow strain
M. C. Juhas; R. D. McCright; R. E. Garrison
Analysis of short-term metabolic alterations in Arabidopsis following changes in the prevailing environmental conditions.
Although a considerable increase in our knowledge concerning the importance of metabolic adjustments to unfavorable growth conditions has been recently provided, relatively little is known about the adjustments which occur in response to fluctuation in environmental factors. Evaluating the metabolic adjustments occurring under changing environmental conditions thus offers a good opportunity to increase our current understanding of the crosstalk between the major pathways which are affected by such conditions. To this end, plants growing under normal conditions were transferred to different light and temperature conditions which were anticipated to affect (amongst other processes) the rates of photosynthesis and photorespiration and characterized at the physiological, molecular, and metabolic levels following this transition. Our results revealed similar behavior in response to both treatments and imply a tight connectivity of photorespiration with the major pathways of plant metabolism. They further highlight that the majority of the regulation of these pathways is not mediated at the level of transcription but that leaf metabolism is rather pre-poised to adapt to changes in these input parameters. PMID:24503159
Florian, Alexandra; Nikoloski, Zoran; Sulpice, Ronan; Timm, Stefan; Araķjo, Wagner L; Tohge, Takayuki; Bauwe, Hermann; Fernie, Alisdair R
Evaluation of chemical conversion material (protective coating) exposed to space environmental conditions
NASA Technical Reports Server (NTRS)
This report focuses on the development of an operational Rutherford backscattering spectrometry (RBS) system and shows the application of such a system on a space environmental test. Thin films of aluminum and tantalum were deposited on diamond substrates. These films were anodized and preexposure characterization spectra obtained using RBS and total hemispherical reflectance. The samples were exposed to energetic protons then postexposure characterization spectra was obtained using the same techniques. Conclusions based on the comparison of preexposure and postexposure spectra are presented. RBS comparison spectra show no change in the metal/metal oxide interface, while the comparison reflectance data indicate change. Explanations for this reflectance change are presented in this report.
Edwards, D. L.
Thermal imaging of cucumber leaves affected by downy mildew and environmental conditions.
Pathogenesis of Pseudoperonospora cubensis causing downy mildew of cucumber resulted in changes in the metabolic processes within cucumber leaves including the transpiration rate. Due to the negative correlation between transpiration rate and leaf temperature, digital infrared thermography permitted a non-invasive monitoring and an indirect visualization of downy mildew development. Depending on the stage of pathogenesis and the topology of chloroses and necroses, infection resulted in a typical temperature pattern. Spatial heterogeneity of the leaf temperature could be quantified by the maximum temperature difference (MTD) within a leaf. The MTD increased during pathogenesis with the formation of necrotic tissue and was related to disease severity as described by linear and quadratic regression curves. Under controlled conditions, changes in temperature of infected leaves allowed the discrimination between healthy and infected areas in thermograms, even before visible symptoms of downy mildew appeared. Environmental conditions during thermographic measurement, in particular air temperature and humidity, as well as water content and age of the leaf influenced the temperature of its surface. Conditions enhancing the transpiration rate facilitated the detection of changes in leaf temperature of infected leaves at early stages of infection. As modified by environmental conditions, MTD alone is not suitable for the quantification of downy mildew severity in the field. PMID:16714311
Oerke, E-C; Steiner, U; Dehne, H-W; Lindenthal, M
Environmental stability control of the intensity of squall lines under low-level shear conditions
NASA Astrophysics Data System (ADS)
The environment for the development and evolution of linearly organized convective systems, i.e., squall lines is diverse for their existence in various climate regions. Understanding the behavior of squall lines under various environmental conditions is required for diagnosing and forecasting the development and intensity of the convective systems. The present study investigates the effects of environmental static stability on the squall-line intensity by conducting a systematic series of idealized cloud-resolving simulations of squall lines that develop in line-perpendicular, low-level westerly shear. Changing the temperature lapse rate with convective available potential energy (CAPE) being unchanged, we showed that the environmental stability in a convectively unstable layer well describes the intensity of the simulated squall lines. A less stable stability is favorable for generating stronger convective systems. The amount of CAPE does not account for the difference in the squall-line intensity in different temperature environments. An environment with a less static stability leads to the development of stronger cold pool, which will strongly controls the scale and strength of convective updrafts, the intensity of tropospheric overturning, and thus the organization and intensity of squall lines. The CAPE value can only be a good measure for diagnosing the development and intensity of the convective systems so long as the environmental static stability is identical. The static stability is a controlling parameter in determining the intensity of squall lines.
Takemi, Tetsuya
Arctic Environmental Changes: Investigation and Interpretation of Environmental Changes During the Transition from Winter to Summer Condition in a Part of Arctic North America.
National Technical Information Service (NTIS)
A detailed investigation and interpretation was made of environmental changes occuring during the transition period between winter and summer conditions in an area situated around the mouth of the Mackenzie River and along the shores of the Beaufort Sea i...
K. V. Abrahamsson
Clothing insulation and temperature, layer and mass of clothing under comfortable environmental conditions
This study was designed to investigate the relationship between the microclimate temperature and clothing insulation (Icl) under comfortable environmental conditions. In total, 20 subjects (13 women, 7 men) took part in this study. Four environmental temperatures were chosen: 14įC (to represent March/April), 25įC (May/June), 29įC (July/August), and 23įC (September/October). Wind speed (0.14ms-1) and humidity (45%) were held constant. Clothing microclimate temperatures were measured at the chest (Tchest) and on the interscapular region (Tscapular). Clothing temperature of the innermost layer (Tinnermost) was measured on this layer 30 mm above the centre of the left breast. Subjects were free to choose the clothing that offered them thermal comfort under each environmental condition. We found the following results. 1) All clothing factors except the number of lower clothing layers (Llower), showed differences between the different environmental conditions (P<0.05). The ranges of Tchest were 31.6 to 33.5įC and 32.2 to 33.4įC in Tscapular. The range of Tinnermost was 28.6 to 32.0įC. The range of the upper clothing layers (Lupper) and total clothing mass (Mtotal) was 1.1 to 3.2 layers and 473 to 1659 g respectively. The range of Icl was 0.78 to 2.10 clo. 2) Post hoc analyses showed that analysis of Tinnermost produced the same results as for that of Icl. Likewise, the analysis of Lupper produced the same result as the analysis of the number of total layers (Ltotal) within an outfit. 3) Air temperature (ta) had positive relationships with Tchest and Tscapular and with Tinnermost but had inverse correlations with Icl, Mtotal, Lupper and Ltotal. Tchest, Tscapular, and Tinnermost increased as ta rose. 4) Icl had inverse relationships with Tchest and Tinnermost, but positive relationships with Mtotal, Lupper and Ltotal. Icl could be estimated by Mtotal, Lupper, and Tscapular using a multivariate linear regression model. 5) Lupper had positive relationships with Icl and Mtotal, but Llower did not. Subjects hardly changed Llower under environmental comfort conditions between March and October. This indicates that each of the Tchest, Mtotal, and Lupper was a factor in predicting Icl. Tinnermost might also be a more influential factor than the clothing microclimate temperature.
Fiberboard material, used in the 9975 shipping package, has been tested for thermal, mechanical and physical properties following environmental conditioning for periods up to 64 weeks. The environments are either representative or bounding of KAMS storage conditions, in order to provide prediction of long-term performance of the 9975 package in KAMS. This report summarizes the data and analysis performed to date. These data show degradation of some properties in some of the environments, but samples have not degraded beyond identified minimum KAMS requirements. Statistical analysis of the data collected to date support the development of a model to predict a service life in KAMS. Further model development and lifetime predictions will be made following additional conditioning and testing in accordance with the task technical plan.
Daugherty, W; Stephen Harris, S
The terrestrial snail, Helix pomatia, adapts to environmental conditions by the modulation of central arousal.
The osmotic stimulation which is able to change the behavioral state of the animal are most effective during rainy weather while they are less effective during dry weather conditions. In isolated CNS preparations from aestivated animals the highest firing activity and serotonin sensitivity of the serotonergic (RPas) heart modulator neurons are recorded during rainy weather and the lowest parameters are observed in dry conditions. In aestivated animals the serotonin (5HT) content in both the CNS and the foot is higher than the dopamine (DA) content during rainy weather, while in dry weather the DA level is higher than the 5HT. The inactivation-reactivation process is accompanied by decreasing both the DA and 5HT levels in the CNS and increasing them in the peripheral organs. Our results suggest that aestivated animals adapt to (favorable and unfavorable) environmental conditions by modulating their central arousal state through changing the levels and distribution of monoamines (5HT, DA) in their body. PMID:18652371
HernŠdi, L; Hiripi, L; Gyori, J; Szabů, Henriette; Vehovszky, Agnes
Adsorption of a Protein Monolayer via Hydrophobic Interactions Prevents Nanoparticle Aggregation under Harsh Environmental Conditions
We find that citrate-stabilized gold nanoparticles aggregate and precipitate in saline solutions below the NaCl concentration of many bodily fluids and blood plasma. Our experiments indicate that this is due to complexation of the citrate anions with Na+ cations in solution. A dramatically enhanced colloidal stability is achieved when bovine serum albumin is adsorbed to the gold nanoparticle surface, completely preventing nanoparticle aggregation under harsh environmental conditions where the NaCl concentration is well beyond the isotonic point. Furthermore, we explore the mechanism of the formation of this albumin Ďcoronaí and find that monolayer protein adsorption is most likely ruled by hydrophobic interactions. As for many nanotechnology-based biomedical and environmental applications, particle aggregation and sedimentation are undesirable and could substantially increase the risk of toxicological side-effects, the formation of the BSA corona presented here provides a low-cost bio-compatible strategy for nanoparticle stabilization and transport in highly ionic environments.
Dominguez-Medina, Sergio; Blankenburg, Jan; Olson, Jana; Landes, Christy F.; Link, Stephan
Hormonal Signal Amplification Mediates Environmental Conditions during Development and Controls an Irreversible Commitment to Adulthood
Many animals can choose between different developmental fates to maximize fitness. Despite the complexity of environmental cues and life history, different developmental fates are executed in a robust fashion. The nematode Caenorhabditis elegans serves as a powerful model to examine this phenomenon because it can adopt one of two developmental fates (adulthood or diapause) depending on environmental conditions. The steroid hormone dafachronic acid (DA) directs development to adulthood by regulating the transcriptional activity of the nuclear hormone receptor DAF-12. The known role of DA suggests that it may be the molecular mediator of environmental condition effects on the developmental fate decision, although the mechanism is yet unknown. We used a combination of physiological and molecular biology techniques to demonstrate that commitment to reproductive adult development occurs when DA levels, produced in the neuroendocrine XXX cells, exceed a threshold. Furthermore, imaging and cell ablation experiments demonstrate that the XXX cells act as a source of DA, which, upon commitment to adult development, is amplified and propagated in the epidermis in a DAF-12 dependent manner. This positive feedback loop increases DA levels and drives adult programs in the gonad and epidermis, thus conferring the irreversibility of the decision. We show that the positive feedback loop canalizes development by ensuring that sufficient amounts of DA are dispersed throughout the body and serves as a robust fate-locking mechanism to enforce an organism-wide binary decision, despite noisy and complex environmental cues. These mechanisms are not only relevant to C. elegans but may be extended to other hormonal-based decision-making mechanisms in insects and mammals.
Schaedel, Oren N.; Gerisch, Birgit; Antebi, Adam; Sternberg, Paul W.
Thermal Cyclic Behavior of Thermal and Environmental Barrier Coatings Investigated Under High-Heat-Flux Conditions
NASA Technical Reports Server (NTRS)
Environmental barrier coatings (EBC's) have been developed to protect silicon-carbide- (SiC) based ceramic components in gas turbine engines from high-temperature environmental attack. With continuously increasing demands for significantly higher engine operating temperature, future EBC systems must be designed for both thermal and environmental protection of the engine components in combustion gases. In particular, the thermal barrier functions of EBC's become a necessity for reducing the engine-component thermal loads and chemical reaction rates, thus maintaining the required mechanical properties and durability of these components. Advances in the development of thermal and environmental barrier coatings (TBC's and EBC's, respectively) will directly impact the successful use of ceramic components in advanced engines. To develop high-performance coating systems, researchers must establish advanced test approaches. In this study, a laser high-heat-flux technique was employed to investigate the thermal cyclic behavior of TBC's and EBC's on SiC-reinforced SiC ceramic matrix composite substrates (SiC/SiC) under high thermal gradient and thermal cycling conditions. Because the laser heat flux test approach can monitor the coating's real-time thermal conductivity variations at high temperature, the coating thermal insulation performance, sintering, and delamination can all be obtained during thermal cycling tests. Plasma-sprayed yttria-stabilized zirconia (ZrO2-8 wt% Y2O3) thermal barrier and barium strontium aluminosilicate-based environmental barrier coatings (BSAS/BSAS+mullite/Si) on SiC/SiC ceramic matrix composites were investigated in this study. These coatings were laser tested in air under thermal gradients (the surface and interface temperatures were approximately 1482 and 1300 C, respectively). Some coating specimens were also subject to alternating furnace cycling (in a 90-percent water vapor environment at 1300 C) and laser thermal gradient cycling tests (in air), to investigate the water vapor effect. All cyclic tests were conducted using a 60-min hot-time temperature.
Zhu, Dongming; Lee, Kang N.; Miller, Robert A.
Water retention of selected microorganisms and Martian soil simulants under close to Martian environmental conditions
NASA Astrophysics Data System (ADS)
Based on the latest knowledge about microorganisms resistant towards extreme conditions on Earth and results of new complex models on the development of the Martian atmosphere we quantitatively examined the water-bearing properties of selected extremophiles and simulated Martian regolith components and their interaction with water vapor under close to Martian environmental conditions. Three different species of microorganisms have been chosen and prepared for our study: Deinococcus geothermalis, Leptothrix sp. OT_B_406, and Xanthoria elegans. Further, two mineral mixtures representing the early and the late Martian surface as well as montmorillonite as a single component of phyllosilicatic minerals, typical for the Noachian period on Mars, were selected. The thermal mass loss of the minerals and bacteria-samples was measured by thermoanalysis. The hydration and dehydration properties were determined under close to Martian environmental conditions by sorption isotherm measurements using a McBain-Bakr quartz spring balance. It was possible to determine the total water content of the materials as well as the reversibly bound water fraction as function of the atmospheres humidity by means of these methods. Our results are important for the evaluation of future space mission outcomes including astrobiological aspects and can support the modeling of the atmosphere/surface interaction by showing the influence on the water inventory of the upper most layer of the Martian surface.
Jšnchen, J.; Bauermeister, A.; Feyh, N.; de Vera, J.-P.; Rettberg, P.; Flemming, H.-C.; Szewzyk, U.
Note: Electrical resolution during conductive atomic force microscopy measurements under different environmental conditions and contact forces
Conductive atomic force microscopy experiments on gate dielectrics in air, nitrogen, and UHV have been compared to evaluate the impact of the environment on topography and electrical measurements. In current images, an increase of the lateral resolution and a reduction of the conductivity were observed in N{sub 2} and, especially, in UHV (where current depends also on the contact force). Both effects were related to the reduction/elimination of the water layer between the tip and the sample in N{sub 2}/UHV. Therefore, since current measurements are very sensitive to environmental conditions, these factors must be taken into consideration when comparisons between several experiments are performed.
Lanza, M.; Porti, M.; Nafria, M.; Aymerich, X. [Dept. Enginyeria Electronica, Universitat Autonoma de Barcelona, Edifici Q, 08193 Bellaterra (Spain); Whittaker, E.; Hamilton, B. [University of Manchester, Sackville Street, Manchester M60 JQD (United Kingdom)
In vitro biocontrol analysis of Alternaria alternata (Fr.) Keissler under different environmental conditions.
The species Trichoderma harzianum was analyzed as possible biocontrol agent of Alternaria alternata under different environmental conditions (water activity and temperature). The strains were analyzed macroscopically to obtain the Index of Dominance. The analysis was completed using two microscopic techniques. T. harzianum showed dominance on contact over A. alternata at all testing temperatures and water activities tested except at 0.95 a(w) and 15 degrees C, at which T. harzianum inhibited A. alternata at a distance. Biocontrol was governed by different mechanisms such as competition for space and nutrients, mycoparasitism, and possible antibiosis. Temperature and water activity significantly influenced fungal growth rate. PMID:17356789
Sempere, F; Santamarina, M P
Portuguese native Artemia parthenogenetica resisting invasion by Artemia franciscana - Assessing reproductive parameters under different environmental conditions
NASA Astrophysics Data System (ADS)
There is widespread interest in the conservation of native Artemia biodiversity. In Portugal, only two known populations of native Artemia remain: one in the Rio Maior salina, the other in the Aveiro salina complex, both of the diploid Artemia parthenogenetica species. All other Portuguese hypersaline environments where Artemia can be found have been invaded by Artemia franciscana, which has eradicated the native strains. Invasiveness and resilience of, respectively, exotic and indigenous species are thought to depend on strain-specific traits and adaptation to local conditions. This work evaluates the reproductive performance of the two Portuguese native strains and the invasive species exposed to different salinities, temperatures, photoperiods and food supplies. Reproduction periods, quantity and quality of offspring varied significantly, depending on both the Artemia strain and environmental conditions. A.†parthenogenetica from Rio Maior reproduced better than A.†franciscana at high salinity (150) and low food supply, which may reflect an adaptation to its biotope that aids its resistance to invasion. But A.†parthenogenetica form Aveiro performed much worse than its invasive competitor, under most of the conditions tested. It is unlikely that A.†franciscana has not been introduced in this salina by chance alone. Other biological traits of the local A.†parthenogenetica or adaptation to unstudied local factors (e.g. pollution) are probably responsible for this strain's survival. Further knowledge on specific local conditions and trait-specific tolerances to biotic and abiotic conditions are needed to understand (non-)invasion patterns and preserve the remaining native populations.
Pinto, Pedro M.; Hontoria, Francisco; Vieira, Natividade; Bio, Ana
A Research on Functional Status, Environmental Conditions, and Risk of Falls in Dementia
This study aimed to determine the effects of disability, physical activity, and functional status as well as environmental conditions on the risk of falls among the elderly with dementia after adjusting for sociodemographic factors. Data were derived from a group including 1210 Malaysian elderly who were demented and noninstitutionalized. The study was a national cross-sectional survey that was entitled ďDeterminants of Health Status among Older Malaysians.Ē Approximately 17% of subjects experienced falls. The results showed that ethnic non-Malay (OR = 1.73) and functional decline (OR = 1.67) significantly increased the risk of falls in samples (P < 0.05). The findings indicated that increased environmental quality (OR = 0.64) significantly decreased the risk of falls (P < 0.05). Disability, age, marital status, educational level, sex differences, and physical activity were found irrelevant to the likelihood of falls in subjects (P > 0.05). It was concluded that functional decline and ethnic non-Malay increased the risk of falls but the increased environmental quality reduced falls.
Eshkoor, Sima Ataollahi; Hamid, Tengku Aizan; Nudin, Siti Sa'adiah Hassan; Mun, Chan Yoke
Characteristics and organization of precipitating features during NAME 2004 and their relationship to environmental conditions
NASA Astrophysics Data System (ADS)
The focus of this study is to examine the characteristics of convective precipitating features (PFs) during the 2004 North American Monsoon Experiment (NAME) and their precursor environmental conditions. The goal is to gain a better insight into the predictability and variability of warm season convective processes in the southern portion of the North American Monsoon core region. The organization and characteristics of PFs are evaluated using composite radar reflectivity images over the southern portion of the Gulf of California. The environmental conditions are assessed using satellite images and a plethora of atmospheric observational analysis maps, such as winds at multiple levels, upper-level divergence, vorticity, vertical air motion, moisture and vertical cross-sections. Our study reveals that most PFs occurred during the afternoon and evening over land, especially near the foothills of the Sierra Madre Occidental. The vast majority of the precipitating features (ė95%) were small, isolated, unorganized, short-lived convective cells. Mesoscale convective systems (MCSs) made up only 5% of the PF population. Nonetheless, these large, long-lived, precipitating features were responsible for 72% of the total precipitation within the radar composite region. An analysis of the number and rainfall produced by these MCSs revealed that they were not constant from day to day, but rather, varied significantly throughout NAME. We found that MCSs were more frequent when the atmosphere is thermodynamically unstable and the wind shear or large-scale dynamics favors the development of organized convection. Lastly, we examined the synoptic conditions associated with episodes of above average MCS rainfall in the southern portion of the NAME core region. Tropical waves were found to be an essential source of moisture and instability in the region. We also found that transient upper-level inverted troughs interact with the upper-level anticyclone to produce a "North American Monsoon Jet Streak" that created favorable dynamical uplift and wind shear conditions for MCS development.
Pereira, Luis Gustavo P.
[Role of micro-organisms in adapting plants to environmental stress conditions].
Due to their sessile nature, plants have always been confronted to various abiotic and biotic stresses in their immediate environment. As a consequence, the survival of plants depended on their ability to adjust rapidly their physiology, development and growth to escape or mitigate the impacts of stress. All plants are known to perceive and respond to stress signals such as drought, heat, salinity, attacks by herbivores and pathogens. Some biochemical processes are common to all plant stress responses including the production of certain stress proteins and metabolites, as well as the modification of the reactive oxygen species (ROS) metabolism. Although there has been extensive research in the plant stress response field, it is not yet known which factors are responsible for conferring to some plant species the capacity to colonize extreme habitats. Although considerable progress has been made in our understanding of plant stress physiology, the contribution of the plant-associated microbial community in the soil, commonly called the rhizosphere, has only recently received enhanced attention. Recent studies showed that some plant species in natural habitats require microbial associations for stress tolerance and survival. Since plants have colonized land, they have evolved mechanisms to respond to changing environmental conditions and settle in extreme habitats. Although many plants lack the adaptive capability to adapt to stress conditions, the ability of a variety of plants to adapt to stress conditions appears to depend on the association with microbes, raising a number of questions: can all plants improve stress tolerance when associated with their appropriate microbial partners? Did we miss identifying the right partners for a given plant species or variety? What distinguishes the microbes and plants that are adapted to extreme environmental conditions from those living in temperate zones? Answers to these questions are likely to revolutionize plant biology and could lead to new methods for a sustainable agriculture. PMID:23419255
Hirt, Heribert
Manipulating individual state during migration provides evidence for carry-over effects modulated by environmental conditions
Despite observational evidence of carry-over effects (COEs, events occurring in one season that produce residual effects on individuals the following seasons), to our knowledge no experimental studies have been carried out to explore how COEs might affect reproductive output. We simulated an environmental perturbation affecting spring-staging migrants to investigate COEs in greater snow geese (Anser caerulescens atlanticus). During three consecutive years, 2037 females captured during spring staging (approx. 3000 km south of their Arctic breeding grounds) were maintained in captivity (with or without access to food) for 0Ė4 days. Duration of captivity (but not food treatment) negatively affected reproductive success, probably through stress response. Reproductive success was reduced by 45Ė71% in 2 years, but not in a third year with unusually favourable breeding conditions. This unprecedented manipulation indicates that COEs can have a strong effect on individual reproductive success in long-distance migrants, but that this effect can be partly compensated for by good environmental conditions on the breeding ground.
Legagneux, Pierre; Fast, Peter L. F.; Gauthier, Gilles; Bety, Joel
Using Magnetically Responsive Tea Waste to Remove Lead in Waters under Environmentally Relevant Conditions
We report the use of a simple yet highly effective magnetite-waste tea composite to remove lead(II) (Pb2+) ions from water. Magnetite-waste tea composites were dispersed in four different types of waterĖdeionized (DI), artificial rainwater, artificial groundwater and artificial freshwaterĖthat mimic actual environmental conditions. The water samples had varying initial concentrations (0.16Ė5.55 ppm) of Pb2+ ions and were mixed with the magnetite-waste tea composite for at least 24 hours to allow adsorption of the Pb2+ ions to reach equilibrium. The magnetite-waste tea composites were stable in all the water samples for at least 3 months and could be easily removed from the aqueous media via the use of permanent magnets. We detected no significant leaching of iron (Fe) ions into the water from the magnetite-waste tea composites. The percentage of Pb adsorbed onto the magnetite-waste tea composite ranged from ?70% to 100%; the composites were as effective as activated carbon (AC) in removing the Pb2+ ions from water, depending on the initial Pb concentration. Our prepared magnetite-waste tea composites show promise as a green, inexpensive and highly effective sorbent for removal of Pb in water under environmentally realistic conditions.
Yeo, Siang Yee; Choi, Siwon; Dien, Vivian; Sow-Peh, Yoke Keow; Qi, Genggeng; Hatton, T. Alan; Doyle, Patrick S.; Thio, Beng Joo Reginald
The Role of Abiotic Environmental Conditions and Herbivory in Shaping Bacterial Community Composition in Floral Nectar
Identifying the processes that drive community assembly has long been a central theme in ecology. For microorganisms, a traditional prevailing hypothesis states that ďeverything is everywhere, but the environment selectsĒ. Although the bacterial community in floral nectar may be affected by both atmosphere (air-borne bacteria) and animals as dispersal vectors, the environmental and geographic factors that shape microbial communities in floral nectar are unknown. We studied culturable bacterial communities in Asphodelus aestivus floral nectar and in its typical herbivorous bug Capsodes infuscatus, along an aridity gradient. Bacteria were sampled from floral nectar and bugs at four sites, spanning a geographical range of 200 km from Mediterranean to semi-arid conditions, under open and bagged flower treatments. In agreement with the niche assembly hypothesis, the differences in bacterial community compositions were explained by differences in abiotic environmental conditions. These results suggest that microbial model systems are useful for addressing macro-ecological questions. In addition, similar bacterial communities were found in the nectar and on the surface of the bugs that were documented visiting the flowers. These similarities imply that floral nectar bacteria dispersal is shaped not only by air borne bacteria and nectar consumers as previously reported, but also by visiting vectors like the mirid bugs.
Samuni-Blank, Michal; Izhaki, Ido; Laviad, Sivan; Bar-Massada, Avi; Gerchman, Yoram; Halpern, Malka
The role of abiotic environmental conditions and herbivory in shaping bacterial community composition in floral nectar.
Identifying the processes that drive community assembly has long been a central theme in ecology. For microorganisms, a traditional prevailing hypothesis states that "everything is everywhere, but the environment selects". Although the bacterial community in floral nectar may be affected by both atmosphere (air-borne bacteria) and animals as dispersal vectors, the environmental and geographic factors that shape microbial communities in floral nectar are unknown. We studied culturable bacterial communities in Asphodelus aestivus floral nectar and in its typical herbivorous bug Capsodes infuscatus, along an aridity gradient. Bacteria were sampled from floral nectar and bugs at four sites, spanning a geographical range of 200 km from Mediterranean to semi-arid conditions, under open and bagged flower treatments. In agreement with the niche assembly hypothesis, the differences in bacterial community compositions were explained by differences in abiotic environmental conditions. These results suggest that microbial model systems are useful for addressing macro-ecological questions. In addition, similar bacterial communities were found in the nectar and on the surface of the bugs that were documented visiting the flowers. These similarities imply that floral nectar bacteria dispersal is shaped not only by air borne bacteria and nectar consumers as previously reported, but also by visiting vectors like the mirid bugs. PMID:24922317
Samuni-Blank, Michal; Izhaki, Ido; Laviad, Sivan; Bar-Massada, Avi; Gerchman, Yoram; Halpern, Malka
Performance of diffusion-barrier scintillation cells under a variety of controlled environmental conditions
The US Department of Energy (DOE) Office of Remedial Action and Waste Technology established the Technical Measurements Center (TMC) at the Grand Junction, Colorado, Projects Office (GJPO), in part, to develop and evaluate new devices for the DOE remedial action projects. The TMC charged the GJPO Radon Laboratory, under the management of UNC Geotech (UNC), with developing and testing a passive scintillation-type, time-averaging radon monitor. Two types of monitors were developed--a diffusion-barrier scintillation cell (DBSC) and a diffusion-barrier liquid scintillation cell (DBLSC). The performance of the DBSCs was tested under different relative humidities, temperatures, and wind speeds. The test results of the DBSCs showed no statistically significant change in accuracy due to the environmental test conditions. Radon-concentration measurement results for diffusion-barrier charcoal canisters (DBCC), exposed along with the DBSCs, did show significant effects due to wind and temperature, but no effects due to relative humidity. The performance of the DBLSCs under a variety of environmental conditions was not tested because a sufficiently sensitive device could not be developed using the existing GJPO liquid-scintillation counting system and a nontoxic counting medium. 10 refs., 10 figs., 10 tabs.
Spangler, R.R.; Langner, G.H., Jr.
Species traits and environmental conditions govern the relationship between biodiversity effects across trophic levels.
Changing environments can have divergent effects on biodiversity-ecosystem function relationships at alternating trophic levels. Freshwater mussels fertilize stream foodwebs through nutrient excretion, and mussel species-specific excretion rates depend on environmental conditions. We asked how differences in mussel diversity in varying environments influence the dynamics between primary producers and consumers. We conducted field experiments manipulating mussel richness under summer (low flow, high temperature) and fall (moderate flow and temperature) conditions, measured nutrient limitation, algal biomass and grazing chironomid abundance, and analyzed the data with non-transgressive overyielding and tripartite biodiversity partitioning analyses. Algal biomass and chironomid abundance were best explained by trait-independent complementarity among mussel species, but the relationship between biodiversity effects across trophic levels (algae and grazers) depended on seasonal differences in mussel species' trait expression (nutrient excretion and activity level). Both species identity and overall diversity effects were related to the magnitude of nutrient limitation. Our results demonstrate that biodiversity of a resource-provisioning (nutrients and habitat) group of species influences foodweb dynamics and that understanding species traits and environmental context are important for interpreting biodiversity experiments. PMID:21901360
Spooner, Daniel E; Vaughn, Caryn C; Galbraith, Heather S
Species traits and environmental conditions govern the relationship between biodiversity effects across trophic levels
Changing environments can have divergent effects on biodiversity-ecosystem function relationships at alternating trophic levels. Freshwater mussels fertilize stream foodwebs through nutrient excretion, and mussel species-specific excretion rates depend on environmental conditions. We asked how differences in mussel diversity in varying environments influence the dynamics between primary producers and consumers. We conducted field experiments manipulating mussel richness under summer (low flow, high temperature) and fall (moderate flow and temperature) conditions, measured nutrient limitation, algal biomass and grazing chironomid abundance, and analyzed the data with non-transgressive overyielding and tripartite biodiversity partitioning analyses. Algal biomass and chironomid abundance were best explained by trait-independent complementarity among mussel species, but the relationship between biodiversity effects across trophic levels (algae and grazers) depended on seasonal differences in mussel species' trait expression (nutrient excretion and activity level). Both species identity and overall diversity effects were related to the magnitude of nutrient limitation. Our results demonstrate that biodiversity of a resource-provisioning (nutrients and habitat) group of species influences foodweb dynamics and that understanding species traits and environmental context are important for interpreting biodiversity experiments. ?? 2011 Springer-Verlag.
Spooner, D. E.; Vaughn, C. C.; Galbraith, H. S.
The phycobilisome, a light-harvesting complex responsive to environmental conditions.
Photosynthetic organisms can acclimate to their environment by changing many cellular processes, including the biosynthesis of the photosynthetic apparatus. In this article we discuss the phycobilisome, the light-harvesting apparatus of cyanobacteria and red algae. Unlike most light-harvesting antenna complexes, the phycobilisome is not an integral membrane complex but is attached to the surface of the photosynthetic membranes. It is composed of both the pigmented phycobiliproteins and the nonpigmented linker polypeptides; the former are important for absorbing light energy, while the latter are important for stability and assembly of the complex. The composition of the phycobilisome is very sensitive to a number of different environmental factors. Some of the filamentous cyanobacteria can alter the composition of the phycobilisome in response to the prevalent wavelengths of light in the environment. This process, called complementary chromatic adaptation, allows these organisms to efficiently utilize available light energy to drive photosynthetic electron transport and CO2 fixation. Under conditions of macronutrient limitation, many cyanobacteria degrade their phycobilisomes in a rapid and orderly fashion. Since the phycobilisome is an abundant component of the cell, its degradation may provide a substantial amount of nitrogen to nitrogen-limited cells. Furthermore, degradation of the phycobilisome during nutrient-limited growth may prevent photodamage that would occur if the cells were to absorb light under conditions of metabolic arrest. The interplay of various environmental parameters in determining the number of phycobilisomes and their structural characteristics and the ways in which these parameters control phycobilisome biosynthesis are fertile areas for investigation.
Grossman, A R; Schaefer, M R; Chiang, G G; Collier, J L
Using magnetically responsive tea waste to remove lead in waters under environmentally relevant conditions.
We report the use of a simple yet highly effective magnetite-waste tea composite to remove lead(II) (Pb(2+)) ions from water. Magnetite-waste tea composites were dispersed in four different types of water-deionized (DI), artificial rainwater, artificial groundwater and artificial freshwater-that mimic actual environmental conditions. The water samples had varying initial concentrations (0.16-5.55 ppm) of Pb(2+) ions and were mixed with the magnetite-waste tea composite for at least 24 hours to allow adsorption of the Pb(2+) ions to reach equilibrium. The magnetite-waste tea composites were stable in all the water samples for at least 3 months and could be easily removed from the aqueous media via the use of permanent magnets. We detected no significant leaching of iron (Fe) ions into the water from the magnetite-waste tea composites. The percentage of Pb adsorbed onto the magnetite-waste tea composite ranged from ?70% to 100%; the composites were as effective as activated carbon (AC) in removing the Pb(2+) ions from water, depending on the initial Pb concentration. Our prepared magnetite-waste tea composites show promise as a green, inexpensive and highly effective sorbent for removal of Pb in water under environmentally realistic conditions. PMID:23818955
Yeo, Siang Yee; Choi, Siwon; Dien, Vivian; Sow-Peh, Yoke Keow; Qi, Genggeng; Hatton, T Alan; Doyle, Patrick S; Thio, Beng Joo Reginald
Dependency of seed dormancy types on embryo traits and environmental conditions in Ribes species.
The hypothesis that seed dormancy may be dependent on environmental conditions and seed morphological traits was tested for six Ribes species, across an altitudinal gradient of 1300†m and a longitudinal separation of 120į. Embryo measurements and seed germination experiments were conducted for R. alpinum L., R. hudsonianum Richardson var. petiolare (Douglas) Jancz., R. nevadaense Kellogg, R. roezlii Regel var. cruentum (Greene) Rehder and R. speciosum Pursh, and data taken from the literature for R. multiflorum Kit. ex Schult. ssp. sandalioticum Arrigoni. Germination was compared with seed viability to reveal proportional seed dormancy, which was then correlated to seed/embryo morphological traits and these traits related to the seed provenance environment. The embryos of all the investigated species are linear underdeveloped and all had a morphological component of seed dormancy (MD). Seeds of R.†roezlii, R.†hudsonianum and R.†nevadaense required a temperature and/or hormone pre-treatment in order to germinate, highlighting morphophysiological seed dormancy (MPD). Seed dormancy was found to be strongly negatively correlated with embryo length, but not with embryo to seed (E:S) ratio or seed mass. Initial embryo length was positively related to mean annual temperature. Seed dormancy in the investigated Ribes species could be quantified and predicted by the interaction of embryo traits and environmental conditions. This approach may be helpful in assessing and predicting seed dormancy in the Ribes genus and in other genera and families with underdeveloped embryos. PMID:24138146
Mattana, E; Stuppy, W H; Fraser, R; Waller, J; Pritchard, H W
Environmental conditions and human drivers for changes to north Ethiopian mountain landscapes over 145years.
As quantitative or spatially distributed studies of environmental change over truly long-term periods of more than 100years are extremely rare, we re-photographed 361 landscapes that appear on historical photographs (1868-1994) within a 40,000km(2) study area in northern Ethiopia. Visible evidence of environmental changes apparent from the paired photographs was analyzed using an expert rating system. The conditions of the woody vegetation, soil and water conservation structures and land management were worse in the earlier periods compared to their present conditions. The cover by indigenous trees is a notable exception: it peaked in the 1930s, declined afterwards and then achieved a second peak in the early 21st century. Particularly in areas with greater population densities, there has been a significant increase in woody vegetation and soil and water conservation structures over the course of the study period. We conclude that except for an apparent upward movement of the upper tree limit, the direct human impacts on the environment are overriding the effects of climate change in the north Ethiopian highlands and that the northern Ethiopian highlands are currently greener than at any other time in the last 145years. PMID:24717722
Nyssen, Jan; Frankl, Amaury; Haile, Mitiku; Hurni, Hans; Descheemaeker, Katrien; Crummey, Donald; Ritler, Alfons; Portner, Brigitte; Nievergelt, Bernhard; Moeyersons, Jan; Munro, Neil; Deckers, Jozef; Billi, Paolo; Poesen, Jean
A sensitivity of squall-line intensity to environmental static stability under various shear and moisture conditions
Squall lines develop in various climate regions having diverse environmental profiles of wind shear, moisture, and temperature. In order to explore the sensitivity of squall lines to these environmental profiles, we have performed an extensive set of numerical simulations under various shear and moisture conditions in midlatitude-continental and tropicalĖoceanic temperature environments. From the results of the sensitivity simulations and the
Tetsuya Takemi
Pulmonary responses of asthmatic and normal subjects to different temperature and humidity conditions in an environmental chamber
Determining the possible adverse health effects of air pollutants can be complicated by differences in the environmental conditions of temperature and humidity. To evaluate the potentially confounding effects of differences in temperature and humidity, we exposed 8 normal male subjects and 8 male subjects with asthma to the extremes in temperature and humidity that could be maintained in an environmental
William L. Eschenbacher; Thomas B. Moore; Thomas J. Lorenzen; John G. Weg; Kenneth B. Gross
[Retrospective analysis of influence of environmental conditions on growth parameters of White Sea edible mussels Mytilus edulis].
Retrospective analysis of influence of environmental conditions on growth parameters of White Sea edible mussels Mytilus edulis has been done by measurements of successive annual rings on shell surface. Analysis by non-linear criterion and Bertalanffy's growth equation allows to deduce that the best environmental condition for edible mussels growth was in 1999 (population from Kastyan island region) and in 2001 (population of Malaya Pir-guba region). The worst one was in 1998 for both populations. PMID:17168474
Zotin, A A; Ozerniuk, N D
Ad libitum adjustments to fluid intake during cool environmental conditions maintain hydration status during a 3-day mountain bike race
ObjectiveIn this study, the hydration status of amateur cyclists who voluntarily adjusted their fluid intake to environmental conditions during a 3-day, 248-km mountain bike (MTB) race was assessed.DesignProspective observational field study.SettingSani2C MTB Race, KwaZulu-Natal, South Africa, 2006.Participants18 randomly selected amateur, male MTB cyclists.Main outcome measuresReported usual fluid intake, environmental conditions, voluntary fluid intake, urine voided, changes in body mass, serum
S. Rose; E. M. Peters-Futre
Evolution of Organics of Astrobiological Interest under Simulated Martian Environmental Conditions
NASA Astrophysics Data System (ADS)
The environmental conditions on Mars seem to have been favourable for the emergence of Life. The search for organics at Mars surface/subsurface is then one of the main goals of the future missions to Mars, NASA MSL (2011) and ESA ExoMars (2016). Due to the current extreme conditions of the Mars surface, the comprehension of the stability of organic molecules in such an environment is essential to prepare these missions, and also to better understand the results of their investigation. With this aim, we develop the MOMIE project (Martian Organics Molecules Irradiation and Evolution), an experiment designed to study the evolution of organics under martian environmental conditions. The first part of this project deals with the interaction between organics and UV radiation. The next step of development now focuses on the oxidative processes, using a combination of UV flux and of oxidants generated in situ. The literature evokes the formation of oxidants as a result of the soil interaction with UV radiations, and then it permits to interpret the NASA Viking biological experiments results. Furthemore, the presence of water or hydrogen peroxide in the soil could also produce oxidants. Then our laboratory experiment reproduces the synergy of soil, water ice and UV radiation to study their impact on organics. First tests were conducted on glycine (chemical standard). Following targets are molecules of astrobiological interest. MOMIE will then assess several questions relative to the quest for organics at Mars : Which organics do we have to search for on Mars ?, or which ones should be resistant or metastable in martian environment ? What is the origin of an organic molecule detected at Mars ? Biotic or abiotic, exogenous or endogenous ? We present here the MOMIE experimental set-up and the first results obtained with it.
Noblet, Audrey; Stalport, F.; Coll, P.; Szopa, C.
Major methodological constraints to the assessment of environmental status based on the condition of benthic communities
NASA Astrophysics Data System (ADS)
The Marine Strategy Framework Directive (MSFD) was published in 2008 and requires Member States to take the necessary measures to achieve or maintain good environmental status in aquatic ecosystems by the year of 2020. The MSFD indicates 11 qualitative descriptors for environmental status assessment, including seafloor integrity, using the condition of the benthic community as an assessment indicator. Member States will have to define monitoring programs for each of the MSFD descriptors based on those indicators in order to understand which areas are in a Good Environmental Status and what measures need to be implemented to improve the status of areas that fail to achieve that major objective. Coastal and offshore marine waters are not frequently monitored in Portugal and assessment tools have only been developed very recently with the implementation of the Water Framework Directive (WFD). The lack of historical data and knowledge on the constraints of benthic indicators in coastal areas requires the development of specific studies addressing this issue. The major objective of the current study was to develop and test and experimental design to assess impacts of offshore projects. The experimental design consisted on the seasonal and interannual assessment of benthic invertebrate communities in the area of future implementation of the structures (impact) and two potential control areas 2 km from the impact area. Seasonal benthic samples were collected at nine random locations within the impact and control areas in two consecutive years. Metrics included in the Portuguese benthic assessment tool (P-BAT) were calculated since this multimetric tool was proposed for the assessment of the ecological status in Portuguese coastal areas under the WFD. Results indicated a high taxonomic richness in this coastal area and no significant differences were found between impact and control areas, indicating the feasibility of establishing adequate control areas in marine ecosystems. Nevertheless, significant differences were found between different seasons and different years, showing that the coastal benthic communities important temporal variations. Although those variations did not affect the status assessment based on metrics that considered the ratio between sensitive and tolerant taxa, diversity indices showed different classifications between seasons and years. These results indicate the need for a temporal stratification of the monitoring programs. That might be achieved by setting different thresholds for specific seasons or selecting specific monitoring seasons. It might also require a regular assessment of the environmental conditions that support the identification of outlier years, which monitoring results should be carefully considered.
Medeiros, Jo"o Paulo; Pinto, Vanessa; SŠ, Erica; Silva, Gilda; Azeda, Carla; Pereira, Tadeu; Quintella, Bernardo; Raposo de Almeida, Pedro; Lino Costa, Josť; Josť Costa, Maria; Chainho, Paula
Can Timely Vector Control Interventions Triggered by Atypical Environmental Conditions Prevent Malaria Epidemics? A Case-Study from Wajir County, Kenya
Background Atypical environmental conditions with drought followed by heavy rainfall and flooding in arid areas in sub-Saharan Africa can lead to explosive epidemics of malaria, which might be prevented through timely vector-control interventions. Objectives Wajir County in Northeast Kenya is classified as having seasonal malaria transmission. The aim of this study was to describe in Wajir town the environmental conditions, the scope and timing of vector-control interventions and the associated resulting burden of malaria at two time periods (1996Ė1998 and 2005Ė2007). Methods This is a cross-sectional descriptive and ecological study using data collected for routine program monitoring and evaluation. Results In both time periods, there were atypical environmental conditions with drought and malnutrition followed by massive monthly rainfall resulting in flooding and animal/human Rift Valley Fever. In 1998, this was associated with a large and explosive malaria epidemic (weekly incidence rates peaking at 54/1,000 population/week) with vector-control interventions starting over six months after the massive rainfall and when the malaria epidemic was abating. In 2007, vector-control interventions started sooner within about three months after the massive rainfall and no malaria epidemic was recorded with weekly malaria incidence rates never exceeding 0.5 per 1,000 population per week. Discussion and Conclusion Did timely vector-control interventions in Wajir town prevent a malaria epidemic? In 2007, the neighboring county of Garissa experienced similar climatic events as Wajir, but vector-control interventions started six months after the heavy un-seasonal rainfall and large scale flooding resulted in a malaria epidemic with monthly incidence rates peaking at 40/1,000 population. In conclusion, this study suggests that atypical environmental conditions can herald a malaria outbreak in certain settings. In turn, this should alert responsible stakeholders about the need to act rapidly and preemptively with appropriate and wide-scale vector-control interventions to mitigate the risk.
Maes, Peter; Harries, Anthony D.; Van den Bergh, Rafael; Noor, Abdisalan; Snow, Robert W.; Tayler-Smith, Katherine; Hinderaker, Sven Gudmund; Zachariah, Rony; Allan, Richard
Relationship between environmental conditions and rates of coastal erosion in Arctic Alaska
NASA Astrophysics Data System (ADS)
Rates of coastal cliff erosion are a function of the geometry and substrate of the coast; storm frequency, duration, magnitude, and wave field; and regional sediment sources. In the Arctic, the duration of sea ice-free conditions limits the time over which coastal erosion can occur, and sea water temperature modulates erosion rates where ice content of coastal bluffs is high. Predicting how coastal erosion rates in this environment will respond to future climate change requires that we first understand modern coastal erosion rates. Arctic coastlines are responding rapidly to climate change. Remotely sensed observations of coastline position indicate that the mean annual erosion rate along a 60-km reach of Alaska's Beaufort Sea coast, characterized by high ice content and small grain size, doubled from 7 m yr-1 for the period 1955-1979 to 14 m yr-1 for 2002-2007. Over the last 30 years the duration of the open water season expanded from ?45 days to ?95 days, increasing exposure of permafrost bluffs to seawater by a factor of 2.5. Time-lapse photography indicates that coastal erosion in this environment is a halting process: most significant erosion occurs during storm events in which local water level is elevated by surge, during which instantaneous submarine erosion rates can reach 1-2 m/day. In contrast, at times of low water, or when sea ice is present, erosion rates are negligible. We employ a 1D coastal cross-section numerical model of the erosion of ice-rich permafrost bluffs to explore the sensitivity of the system to environmental drivers. Our model captures the geometry and style of coastal erosion observed near Drew Point, Alaska, including insertion of a melt-notch, topple of ice-wedge-bounded blocks, and subsequent degradation of these blocks. Using consistent rules, we test our model against the temporal pattern of coastal erosion over two periods: the recent past (~30 years), and a short (~2 week) period in summer 2010. Environmental conditions used to drive model runs for the summer of 2010 include ground-based measurements of meteorological conditions (air temperature, wind speed, wind direction) and coastal waters (water level, wave field, water temperature), supplemented by high temporal frequency (4 frames/hour) time-lapse photography of the coast. Reconstruction of the 30-year coastal erosion history is accomplished by assembling published observations and records of meteorology and sea ice conditions, including both ground and satellite-based records, to construct histories of coastline position and environmental conditions. We model wind-driven water level set-up, the local wave field, and water temperature, and find a good match against the short-term erosion record. We then evaluate which environmental drivers are most significant in controlling the rates of coastal erosion, and which melt-erosion rule best captures the coastal history, with a series of sensitivity analyses. The understanding gained from these analyses provides a foundation for evaluating how continuing climate change may influence future coastal erosion rates in the Arctic.
Barnhart, K. R.; Anderson, R. S.; Overeem, I.; Wobus, C. W.; Clow, G. D.; Urban, F. E.; LeWinter, A. L.; Stanton, T. P.
Micro-environmental conditions modulate protein secretion and infectivity of the Trichinella spiralis L1 larva.
After digestion of infected meat the free L1 of Trichinella spp. penetrate the intestinal mucosa where they moult to the mature adult stage. We have used proteomics to identify changes in protein secretion during in vitro culture of free T. spiralis muscle larvae under different environmental conditions, and to correlate these changes with their infectivity in mice. Muscle larvae were cultured in different media (RPMI-1640, C-199 and HBSS) under conditions of anaerobiosis, microaerobiosis and in 5% CO(2) at 37 degrees C. Following incubation the larval excretory/secretory proteins were analysed by two-dimensional gel electrophoresis and the larvae were used to orally infect naÔve CD1 mice. For all culture media tested, infectivity of the L1 was preserved following incubation in anaerobic conditions. In contrast, the infectivity of worms cultured in nutrient-rich media was almost completely abolished in both microaerobiosis and in the presence of 5% CO(2). Some infectivity was retained in poor or reduced culture media. Comparative analysis of larval infectivity and protein secretion showed that loss of infectivity correlated with the appearance of non-tyvelosylated proteins that in turn may be related to the onset of moulting. PMID:19046809
Bolas-FernŠndez, Francisco; Dea-Ayuela, MarŪa Auxiliadora; Connolly, Bernadette; Robinson, Mark W
Environmental complexity affects contextual fear conditioning following hippocampal lesions in rats.
Contextual fear conditioning has become a benchmark measure for hippocampal function, even though several studies report successful acquisition in hippocampal-damaged rodents. The current study examined whether environmental complexity may account for these discrepancies. We directly compared single-session contextual fear conditioning in rats in a simple vs. complex environment. Hippocampal lesions led to reduced fear conditioning in both contexts, as measured by freezing, but the effect was significantly greater in the complex context. As well, lesions led to generalized fear when the complex context was paired with shock, but not when the simple context was paired. We suggest that the representation of the simple context formed by rats with hippocampal lesions was adequate to support associative learning, but the representation of the complex context, which depended to a greater extent on relational learning, was not. The results were interpreted as consistent with theories of hippocampal function that emphasize its role in integrating multiple stimulus elements in a memory trace. PMID:17415748
Moses, Sandra N; Winocur, Gordon; Ryan, Jennifer D; Moscovitch, Morris
Interactions of environmental conditions and mechanical loads have influence on matrix turnover by nucleus pulposus cells.
Disc degeneration is associated with several changes in the physicochemical environment of intervertebral disc cells. Nucleus pulposus (NP) cells in the center of degenerated discs are exposed to decreased glucose supply, osmolarity, pH, and oxygen levels. To understand the complexity of these interactions on a cellular level, we designed standardized experiments in which we compared responses to these environmental factors under normal levels with those seen under two different degrees of disc degeneration. We hypothesized that these changes in environmental stimuli influence gene expression of matrix proteins and matrix degrading enzymes and alter their responses to cyclic hydrostatic pressure (HP). Our results suggest that a simulation of degenerative conditions influences the degradation of disc matrix through impairing matrix formation and accelerating matrix resorption via up- or down-regulation of the respective target genes. The greatest effects were seen for decreases in glucose concentration and pH. Low oxygen had little influence. HP had little direct effect but appeared to counteract matrix degradation by reducing or inverting some of the adverse effects of other stimuli. For ongoing in vitro studies, interactions between mechanical stimuli and factors in the physicochemical environment should not be ignored as these could markedly influence results. PMID:21674606
Neidlinger-Wilke, Cornelia; Mietsch, Antje; Rinkler, Christina; Wilke, Hans-Joachim; Ignatius, Anita; Urban, Jill
Differential display of skin mRNAs regulated under varying environmental conditions in a mudskipper.
To understand the molecular mechanisms underlying the terrestrial adaptation, as well as adaptation to different salinities, of the euryhaline and amphibious mudskipper ( Periophthalmus modestus), we have looked for the skin mRNAs that change during varying environmental conditions. Using differential mRNA display polymerase chain reaction, we compared skin mRNAs in mudskipper transferred from isotonic 30% seawater to fresh water or to seawater for 1 day and 7 days, as well as those kept out of water for 1 day. At the end of these periods, poly(A(+))RNA was prepared from the Cl(-)-secreting pectoral skins and also from the outer opercular skins where ion transport is negligible, and analyzed by differential display. We identified four cDNA products expressed differently under various environments as homologues of known genes. A further 34 cDNAs were expressed differentially, but they have no significant homology to identified sequences in GenBank. Northern blots demonstrate that mRNA levels of the actin-binding protein and the platelet-activating factor acetylhydrolase increased in the pectoral skins during seawater acclimation. The mRNA of the 90 kDa heat shock protein was down-regulated in water-deprived and freshwater fish, whose plasma cortisol levels were high. The aldolase mRNA was induced in both skins after desiccation. These four genes may be involved in the environmental adaptations. PMID:12122461
Sakamoto, T; Yasunaga, H; Yokota, S; Ando, M
Staphylococcus aureus metabolic response to changing environmental conditions - A metabolomics perspective.
Microorganisms preserve their metabolic function against a wide range of external perturbations including biotic or abiotic factors by utilizing cellular adaptations to maintain cell homeostasis. Functional genomics aims to detect such adaptive alterations on the level of transcriptome, proteome and metabolome to understand system wide changes and to identify interactions between the different levels of biochemical organization. Microbial metabolomics measures metabolites, the direct biochemical response to the environment, and is pivotal to the understanding of the variability and dynamics of bacterial cell metabolism. Metabolomics can measure many different types of compounds including primary metabolites, secondary metabolites, second messengers, quorum sensing compounds and others, which all contribute to the complex bacterial response to an environmental change. Recent data confirmed that many metabolic processes in pathogenic bacteria are linked to virulence and invasive capabilities. Deciphering bacterial metabolism in response to specific environmental conditions and in specific genetic backgrounds will help map the complex network between the metabolome and the other "-omes". Here, we will review a selection of case studies for the pathogenic Gram-positive bacterium Staphylococcus aureus and summarize the current state of metabolomics literature covering staphylococci metabolism under different physiological states. PMID:24439195
Liebeke, Manuel; Lalk, Michael
Classifying movement behaviour in relation to environmental conditions using hidden Markov models.
1. Linking the movement and behaviour of animals to their environment is a central problem in ecology. Through the use of electronic tagging and tracking (ETT), collection of in situ data from free-roaming animals is now commonplace, yet statistical approaches enabling direct relation of movement observations to environmental conditions are still in development. 2. In this study, we examine the hidden Markov model (HMM) for behavioural analysis of tracking data. HMMs allow for prediction of latent behavioural states while directly accounting for the serial dependence prevalent in ETT data. Updating the probability of behavioural switches with tag or remote-sensing data provides a statistical method that links environmental data to behaviour in a direct and integrated manner. 3. It is important to assess the reliability of state categorization over the range of time-series lengths typically collected from field instruments and when movement behaviours are similar between movement states. Simulation with varying lengths of times series data and contrast between average movements within each state was used to test the HMMs ability to estimate movement parameters. 4. To demonstrate the methods in a realistic setting, the HMMs were used to categorize resident and migratory phases and the relationship between movement behaviour and ocean temperature using electronic tagging data from southern bluefin tuna (Thunnus maccoyii). Diagnostic tools to evaluate the suitability of different models and inferential methods for investigating differences in behaviour between individuals are also demonstrated. PMID:19563470
Patterson, Toby A; Basson, Marinelle; Bravington, Mark V; Gunn, John S
Evidence for the role of environmental agents in the initiation or progression of autoimmune conditions.
The concordance of autoimmune disease among identical twins is virtually always less than 50% and often in the 25-40% range. This observation, as well as epidemic clustering of some autoimmune diseases following xenobiotic exposure, reinforces the thesis that autoimmune disease is secondary to both genetic and environmental factors. Because nonliving agents do not have genomes, disease characteristics involving nonliving xenobiotics are primarily secondary to host phenotype and function. In addition, because of individual genetic susceptibilities based not only on major histocompatibility complex differences but also on differences in toxin metabolism, lifestyles, and exposure rates, individuals will react differently to the same chemicals. With these comments in mind it is important to note that there have been associations of a number of xenobiotics with human autoimmune disease, including mercury, iodine, vinyl chloride, canavanine, organic solvents, silica, l-tryptophan, particulates, ultraviolet radiation, and ozone. In addition, there is discussion in the literature that raises the possibility that xenobiotics may also exacerbate an existing autoimmune disease. In this article we discuss these issues and, in particular, the evidence for the role of environmental agents in the initiation or progression of autoimmune conditions. With the worldwide deterioration of the environment, this is a particularly important subject for human health.
Powell, J J; Van de Water, J; Gershwin, M E
Food for thought: Conditions for discourse reflection in the light of environmental assessment
People tend to take notice of what is happening around them selectively. Discourses-frames through which actors give meaning to aspects of the world-act as built-in filters that distinguish relevant from irrelevant data. Use of knowledge generated by environmental assessments (EAs) in decision-making may be understood from this perspective. Environmental knowledge that is inconsistent with dominant discourses runs the risk of being ignored. Discourses on the value of EA as a tool for decision-making may have a similar effect. Stimulating decision-makers and stakeholders to critically reflect on and reconsider their discourses in the light of EAs-also known as frame reflection or policy learning-may enhance the probability that these assessments and the knowledge that they generate impact upon decision-making. Up to now little has been written about how discourse reflection in the context of EA can be promoted. Valuable inputs are fragmented over different bodies of literature. In this paper we draw from these bodies to identify favourable conditions for discourse reflection.
Runhaar, Hens, E-mail: email@example.com [Copernicus Institute for Sustainable Development and Innovation, Utrecht University, P.O. Box 80, 115, 3508 TC Utrecht (Netherlands); Runhaar, Piety R., E-mail: email@example.com [Organisational Psychology and Human Resource Development, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Oegema, Tammo, E-mail: email@example.com [IMSA Amsterdam, Prins Hendriklaan 15, 1075 AX Amsterdam (Netherlands)
Optimization of mechanical oil spill recovery equipment under variable environmental conditions
NASA Astrophysics Data System (ADS)
Oil spills in marine environments may cause significant damage to marine and coastal ecosystems if not recovered quickly and efficiently. Although mechanical recovery is the most commonly used oil spill response technique, it can be very time consuming and expensive when employed at a large scale due, to its low recovery rates. The goal of this work was to optimize mechanical oil spill recovery for various environmental conditions by analyzing the recovery process and identifying parameters with the most significant impact on the recovery efficiency. As a result of this work, laboratory equipment and procedures tailored to the study of oil spill recovery at small scale were developed. A number of materials and surface patterns that can increase the adhesion skimmer recovery efficiency up to three times were identified and tested in a full scale oil spill recovery study.
Broje, Viktoria A.
[Risk factors for children's population health in stressed environmental conditions of lead pollition].
Adverse environmental conditions in Shymkent significantly increase the risk of accumulation of lead in the bodies of the children of the third generation of the population residing in the contaminated areas, cause deteriorations of antioxidant defense in the respiratory system, greatly decline barrier-protective properties of cellular systems of the local immunity, disturb the process of hematopoiesis. Performed statistical analysis of the data permitted to identify a correlation relationship between the accumulation of lead in the soil and the change in the functional activity of the cells of buccal cheek epithelium, catalase activity in expired breath condensate. Haematological signs of lead poisoning include not only the number of reticulocytes, but also the correction (RPI) for the alteration with allowances made for the maturation of reticulocytes in peripheral blood circulation as early criterion for toxic anemia. PMID:24624825
Baidaulet, I O; Namazbaeva, Z I; Dasybayeva, G N; Bazeluk, L T; Sabirov, Zh V; Kusainova, D S
Revegetation processes and environmental conditions in abandoned peat production fields in Estonia
NASA Astrophysics Data System (ADS)
As a result of peat extraction, peat production has been finished in Estonia at different times in 154 peat production areas and 9,500 ha (~1% of peatlands) are abandoned, although the peat reserves are not exhausted yet; besides, several areas are not properly recultivated. In addition 12,000 ha of fens (oligotrophic peat layers) are drained and used as grasslands. If the abandoned and non-recultivated peat production areas are not vegetated, their CO2 emission is considerable and peat mineralises in such areas. The aim of the study was to find out specific ecological and geological factors, which affect recovering of peatlands and influence the recultivation. During the revision the amount and quality of the remained reserves, as well as the state of water regime, drainage network and revegetation was assessed in all 154 abandoned peat production areas. The study showed that the state of them is very variable. Some of them are covered with forest, prevailingly with birches at former drainage ditches, later supplemented by pine trees. In the others predominate grasses among plants, and various species of moss (Cladonia rei, Bryum caespiticum, Sphagnum ripariuma, Sphagnum squarrosum) occur as well. Besides, some abandoned areas are completely overgrown with cotton grass. Open abandoned peat areas, which are not covered by vegetation, are much rarer. We found out, that water regime among the factors plays most important role. Moreover abandoned peat production fields, where the environmental conditions have changed - are appropriate for growth of several moss species, which cannot inhabit the areas already occupied by other species. The most interesting discovers were: second growing site of Polia elongata in West-Estonia and Ephemerum serratum, last found in Estonia in the middle of the 19th century, was identified in central Estonia. Also Campylopus introflexus, what was unknown in Estonia. However, the changes in environmental conditions influence the peat layers structure and technical characteristics of organic soils that affect the vegetation of peatlands.
Orru, M.; Orru, H.
Relationship between fumonisin production and FUM gene expression in Fusarium verticillioides under different environmental conditions.
Fusarium verticillioides is the main source of fumonisins, a group of mycotoxins that can contaminate maize-based food and feed and cause diseases in humans and animals. The study of the effect of different environmental conditions on toxin production should provide information that can be used to develop strategies to minimize the risk. This study analysed the effect of temperature (15įC-35įC), water activity (a(w): 0.999-0.93), salinity (0-125 g l(-1) NaCl) and pH (5-8) on the growth and production of fumonisins B(1) (FB1), B(2) (FB2) and B(3) (FB3) and the expression of FUM1 and FUM21 in F. verticillioides. The highest growth rate was measured at 25įC, a(w) of 0.998-0.99 and 0-25 g l(-1) of NaCl. Optimal conditions for fumonisin production were 30įC, a(w) of 0.99, 25 g l(-1) of NaCl and pH 5; nevertheless, the strain showed a good adaptability and was able to produce moderate levels of fumonisins under a wide range of conditions. Gene expression mirrored fumonisin production profile under all conditions with the exception of temperature: FUM1 and FUM21 expression was highest at 15įC, while maximum fumonisin production was at 30įC. These data indicate that a post-transcriptional regulation mechanism could account for the different optimal temperatures for FUM gene expression and fumonisin production. PMID:23167929
Fanelli, Francesca; Iversen, Anita; Logrieco, Antonio F; MulŤ, Giuseppina
Assessment of the environmental impact from tritium releases under normal operation conditions and after accidents
In view of the public acceptance and the licensing procedure of projected fusion reactors, the release of tritium during normal operation as well as after accidents is a significant safety aspect. Tritium, being chemically identical to hydrogen and thus interacting directly with water and organic substances, differs considerably from the behaviour of other radionuclides in the environment. Therefore, the two consequence assessment codes UFOTRI and NORMTRI have been developed and applied to estimate the doses to the public from releases of tritium under accidental and routine conditions, respectively. In the frame of ITER (International Thermonuclear Experimental Reactor) and SEAFP (Safety and Environmental Aspects of Fusion Power) the dose/release translation has been determined for typical and various worst case release scenarios. Under worst case accidental release conditions, the dose/release translation for the early dose to an individual at the fence may range from 0.5 to 1 mSv/g HTO. The result for the EDE at the fence is up to 3 mSv/g HTO. The collective accidental and dose/release translation is about 2.5 manSv/g HTO. However, due to processes inside the facility, only a small fraction of the mobilised activity may be released into the environment. 24 refs.
Raskob, W. [Forschungszentrum Karlsruhe GmbH (Germany)
A nanofluidic device for single molecule studies with in situ control of environmental solution conditions.
We report an approach to study the in situ conformational response of single biomolecules such as DNA to a change in environmental solution conditions. These conditions are, for example, the composition of the buffer or the presence of protein. For this purpose, we designed and fabricated a nanofluidic device featuring two arrays of parallel nanochannels in a perpendicular configuration. The cross-sections of the channels are rectangular with a diameter down to 175 nm. These lab-on-a-chip devices were made of polydimethylsiloxane (PDMS) cast on a high quality master stamp, obtained by proton beam writing and UV lithography. Biomolecules can be inserted into the device through the array of channels in one direction, whereas the buffer can be exchanged through the intersecting array of channels in the other direction. A buffer exchange time inside the grid of nanochannels of less than one second was measured by monitoring the conductivity of salt solutions. The exchange time of a protein was typically a few seconds, as determined by imaging the influx of fluorescence labelled protamine. We demonstrate the functionality of the device by investigating the compaction of DNA by protamine and the unpacking of pre-compacted DNA through an increase in the concentration of salt. PMID:23674166
Zhang, Ce; Jiang, Kai; Liu, Fan; Doyle, Patrick S; van Kan, Jeroen A; van der Maarel, Johan R C
The Effects of Varying Environmental Conditions on the Emission Spectra of Meteorites
NASA Astrophysics Data System (ADS)
With NASA's OSIRIS-REx mission due to launch to asteroid 101955 Bennu (previously known as 1999 RQ36) in 2016, preparations are well underway [4]. Once there, the OTES (OSIRIS-Rex Thermal Emission Spectrometer) instrument will map the asteroid's surface to derive thermal and compositional properties [4], by comparing spectra to those of known samples measured in the laboratory. Previous studies have shown that samples can exhibit differen ces in emission spectra due to composition, grain size and the environmental conditions in which they are measured [3,5,7], however the magnitude of these variations for asteroidal material require more study. The aim of this work is to determine whether laboratory samples need to be measured in a thermal environment like that on the asteroid's surface for correct interpretation of returning data from OTES: to do this, the Lunar Environment Chamber in the Planetary Spectroscopy Facility at Oxford University [7] was used to simulate the expected conditions on Bennu while a selection of ground meteorite samples were measured.
Thomas, I. R.; Bowles, N. E.; Connolly, H. C.; Kilgore, M.; Lauretta, D. S.
Migration path annotation: cross-continental study of migration-flight response to environmental conditions.
Understanding the movements of animals is pivotal for understanding their ecology and predicting their survival in the face of rapid global changes to climate, land use, and habitats, thus facilitating more effective habitat management. Migration by flying animals is an extreme form of movement that may be especially influenced by weather. With satellite telemetry studies, and the growing availability of information about the Earth's weather and land surface conditions, many data are collected that can advance our understanding about the mechanisms that shape migrations. We present the track annotation approach for movement data analysis using information about weather from the North American Reanalysis data set, a publicly available, regional, high-resolution model-observation hybrid product, and about topography, from a publicly available high-resolution digital elevation model (DEM). As a case study, we present the analysis of the response to environmental conditions in three contrasting populations of Turkey Vultures (Cathartes aura) across North America, tracked with a three-dimensional GPS-based sensor. Two populations in the east and west coasts of the United States responded similarly to weather, indicating use of both slope and thermal soaring. Continental-interior, "Plains populations," exhibited a different migratory pattern primarily indicative of thermal soaring. These differences help us understand the constraints and behaviors of soaring migrants. The track annotation approach allowed large-scale comparative study of movement in an important migratory species, and will enable similar studies at local to global scales. PMID:21939059
Mandel, James T; Bohrer, Gil; Winkler, David W; Barber, David R; Houston, C Stuart; Bildstein, Keith L
Environmental Conditions Affect the Kinetics of Nucleation of Amyloid Fibrils and Determine Their Morphology
To understand and tackle amyloid-related diseases, it is crucial to investigate the factors that modulate amyloid formation of proteins. Our previous studies proved that the N47A mutant of the ?-spectrin SH3 (Spc-SH3) domain forms amyloid fibrils quickly under mildly acidic conditions. Here, we analyze how experimental conditions influence the kinetics of assembly and the final morphology of the fibrils. Early formation of curly fibrils occurs after a considerable conformational change of the protein and the concomitant formation of small oligomers. These processes are strongly accelerated by an increase in salt concentration and temperature, and to a lesser extent by a reduction in pH. The rate-limiting step in these events has a high activation enthalpy, which is significantly reduced by an increase in NaCl concentration. At low-to-moderate NaCl concentrations, the curly fibrils convert to straight and twisted amyloid fibrils after long incubation times, but only in the presence of soluble species in the mixture, which suggests that the curly fibrils and the twisted amyloid fibrils are diverging assembly pathways. The results suggest that the influence of environmental variables on protein solvation is crucial in determining the nucleation kinetics, the pathway of assembly, and the final fibril morphology.
Morel, Bertrand; Varela, Lorena; Azuaga, Ana I.; Conejero-Lara, Francisco
Calcification intensity in planktonic Foraminifera reflects ambient conditions irrespective of environmental stress
NASA Astrophysics Data System (ADS)
Planktonic Foraminifera are important marine calcifiers, and the ongoing change in the oceanic carbon system makes it essential to understand the influence of environmental factors on the biomineralization of their shells. The amount of calcite deposited by planktonic Foraminifera during calcification has been hypothesized to reflect a range of environmental factors. However, it has never been assessed whether their calcification only passively responds to the conditions of the ambient seawater or whether it reflects changes in resource allocation due to physiological stress. To disentangle these two end-member scenarios, an experiment is required where the two processes are separated. A natural analogue to such an experiment occurred during the deposition of the Mediterranean sapropels, where large changes in surface water composition and stratification at the onset of the sapropel deposition were decoupled from local extinctions of planktonic Foraminifera species. We took advantage of this natural experiment and investigated the reaction of calcification intensity, expressed as mean area density (MAD), of four species of planktonic Foraminifera to changing conditions during the onset of Sapropel S5 (126-121 ka) in a sediment core from the Levantine Basin. We observed a significant relationship between MAD and surface water properties, as reflected by stable isotopes in the calcite of Foraminifera shells, but we failed to observe any reaction of calcification intensity on ecological stress during times of decreasing abundance culminating in local extinction. The reaction of calcification intensity to surface water perturbation at the onset of the sapropel was observed only in surface-dwelling species, but all species calcified more strongly prior to the sapropel deposition and less strongly within the sapropel than at similar conditions during the present-day. These results indicate that the high-salinity environment of the glacial Mediterranean Sea prior to sapropel deposition induced a~more intense calcification, whereas the freshwater injection to the surface waters associated with sapropel deposition inhibited calcification. The results are robust to changes in carbonate preservation and collectively imply that changes in normalized shell weight in planktonic Foraminifera should reflect mainly abiotic forcing.
Weinkauf, M. F. G.; Moller, T.; Koch, M. C.; Ku?era, M.
Cold-water coral growth under extreme environmental conditions, the Cape Lookout area, NW Atlantic
NASA Astrophysics Data System (ADS)
The Cape Lookout cold-water coral area off the coast of North Carolina forms the shallowest and northernmost cold-water coral mound area on the Blake Plateau in the NW Atlantic. Cold-water coral habitats near Cape Lookout are occasionally bathed in the Gulf Stream, which is characterised by oligotrophic warm water and strong surface currents. Here, we present the first insights into the mound distribution and morphology, sedimentary environment and coral cover and near-bed environmental conditions as recorded by bottom landers from this coral area. The mounds occur between 320 and 550 m water depth and are characterised by high acoustic backscatter indicating the presence of hard structure. Three distinct mound morphologies were observed: (1) a mound with a flattened top at 320 m, (2) multi-summited mounds with a teardrop shape in the middle part of the area and (3) a single mound at 540 m water depth. Echosounder profiles show the presence of a strong reflector underneath all mound structures that forms the base of the mounds. This reflector cropped out at the downstream side of the single mound and consists of carbonate slabs. Video analysis revealed that all mounds are covered by Lophelia pertusa and that living colonies only occur close to the summits of the SSW side of the mounds, which is the side that faces the strongest currents. Off-mound areas were characterised by low backscatter and sediment ripples, indicating the presence of relatively strong bottom currents. Two bottom landers were deployed amidst the coral mounds between December 2009 and May 2010. Both landers recorded prominent events, characterised by large fluctuations in environmental conditions near the seabed as well as in the overlying water column. The period between December and April was characterised by several events of increasing temperature and salinity, coinciding with increased flow and near-bed acoustic backscatter. During these events temperature fluctuated by up to 9 įC within a day, which is the largest temperature variability as measured so far in a cold-water coral habitat. Warm events, related to Gulf Stream meanders, had the duration of roughly 1 week and the current during these events was directed to the NNE. The consequences of such events must be significant given the strong effects of temperature on the metabolism of cold-water corals. Furthermore, elevated acoustic backscatter values and high mass fluxes were also recorded during these events, indicating a second stressor that may affect the corals. The abrasive nature of sand in combination with strong currents might sand blast the corals. We conclude that cold-water corals near Cape Lookout live under extreme conditions that limit mound growth at present.
Mienis, F.; Duineveld, G. C. A.; Davies, A. J.; Lavaleye, M. M. S.; Ross, S. W.; Seim, H.; Bane, J.; van Haren, H.; Bergman, M. J. N.; de Haas, H.; Brooke, S.; van Weering, T. C. E.
Calcification intensity in planktonic Foraminifera reflects ambient conditions irrespective of environmental stress
NASA Astrophysics Data System (ADS)
Planktonic Foraminifera are important marine calcifiers, and the ongoing change in the oceanic carbon system makes it essential to understand the influence of environmental factors on the biomineralisation of their shells. The amount of calcite deposited by planktonic Foraminifera during calcification has been hypothesized to reflect a range of environmental factors. However, it has never been assessed whether their calcification only passively responds to the conditions of the ambient seawater or whether it reflects changes in resource allocation due to physiological stress. To disentangle these two end-member scenarios, an experiment is required where the two processes are separated. A natural analogue to such an experiment occurred during the deposition of the Mediterranean sapropels, where large changes in surface water composition and stratification at the onset of the sapropel deposition were decoupled from local extinctions of planktonic Foraminifera species. We take advantage of this natural experiment and investigate the reaction of calcification intensity, expressed as size-normalized weight (SNW), of four species of planktonic Foraminifera to changing conditions during the onset of Sapropel S5 (126-121 ka) in a sediment core from the Levantine Basin. We observe a significant relationship between SNW and surface water properties, as reflected by stable isotopes in the calcite of Foraminifera shells, but we failed to observe any reaction of calcification intensity on ecological stress during times of decreasing abundance culminating in local extinction. The reaction of calcification intensity to surface water perturbation at the onset of the sapropel was observed only in surface dwelling species, but all species calcified more strongly prior to the sapropel deposition and less strongly within the sapropel than at comparable conditions during the present day. These results indicate that the high-salinity environment of the glacial Mediterranean Sea prior to sapropel deposition induced a more intense calcification, whereas the freshwater injection to the surface waters associated with sapropel deposition inhibited calcification. The results are robust to changes in carbonate preservation and collectively imply that changes in normalized shell weight in planktonic Foraminifera should reflect mainly abiotic forcing.
Weinkauf, M. F. G.; Moller, T.; Koch, M. C.; Ku?era, M.
Biofilm formation and exopolysaccharide (EPS) production by Cronobacter sakazakii depending on environmental conditions.
Biofilm matrices are formed largely of extracellular polymeric substance (EPS). This study was conducted to investigate biofilm formation and EPS production by Cronobacter sakazakii under various conditions (media, nutrition, and relative humidity (RH)) by quantification of EPS and cell populations, Field Emission Scanning Electron Microscope (FE-SEM), and colony observation. Various agar media conditions (TSA without dextrose (W/D), M9 minimum salt medium (MSM) agar, and M9 MSM agar with 3% glucose, 3% NaCl, 3% Tween 80, 3% sucrose, and adjusted to pH 5 with HCl) were prepared. C.†sakazakii biofilm formed on the surface of stainless steel coupons (SSCs) immersed in TSB W/D and M9 MSM with or without 0, 1, 3, and 5% sucrose and subsequently exposed to various RH levels (23, 43, 68, 85, and 100%). EPS production by C.†sakazakii on TSA W/D was significantly higher than that on other media after 1 and 2 days. However, C.†sakazakii ATCC 12868 produced the highest levels of EPS (209.18†Ī†16.13 and 207.22†Ī†4.14†?g/mL after 1 and 2 days, respectively) on M9 MSM agar with 3% sucrose. Regarding C.†sakazakii ATCC 12868 biofilm formed on the surface of SSCs immersed in M9 MSM with 0, 1, 3, and 5% sucrose and subsequently exposed to various RHs, populations were significantly different among the various RHs and sucrose concentrations, and EPS production was significantly higher (4.69†mg/L) compared to other sucrose concentrations (0%:0.71†mg/L and 1%:0.98†mg/L), except for M9 MSM with 3% sucrose (2.97†mg/L) (P†?†0.05). From these results, biofilm formation and EPS production by C.†sakazakii differed depending on the nutrient or environmental conditions provided to the cells. PMID:23498180
Jung, Jin-Ho; Choi, Na-Young; Lee, Sun-Young
Benthic foraminifera as indicators of hydrologic and environmental conditions in the Ross Sea (Antarctica)
NASA Astrophysics Data System (ADS)
This study, present data on benthic foraminiferal assemblages from four box cores collected in different areas of the Ross Sea during the 2005 oceanographic cruise in the framework of the Italian Antarctic Research National Programme (PNRA). Based on magnetic susceptibility, biosiliceous content, and micropaleontological analysis, the sediment cores provide a record of glacial retreat and Holocene environmental changes in the Ross Sea during the last 11 kyr BP. Sediment lithologies range between diamicton to surficial diatomaceous mud, the intermediate levels being glacial-marine sediment. The sedimentary sections include diatomaceous glacial-marine deposit over transitional (proximal grounding zone) glacial-marine sediment. The study revealed that the Ross Sea contains typical Antarctic foraminifera fauna with the dominance of agglutinated taxa. Relatively elevated abundances, richness and diversity were common in the northernmost site, where the water column was characterized by relatively warmer intermediate waters and by the presence of the colder High Salinity Shelf Water (HSSW) occupying the deepest part of the basin. Here, the assemblage was dominated by Miliammina arenacea and the more abundant species were Trochammina quadricamerata and Lagenammina difflugiformis. In the southernmost site and in the eastern Ross Sea, richness and diversity were low and the most significant species were Trochammina sp., and Reophax sp. M. arenacea was ubiquitous in all the samples and sites, confirming its tolerance to cold corrosive bottom waters and salinity fluctuations as well as its uniquely high preservation potential. Moreover, elevated abundances, richness and diversity were common in the upper portion of the core which represents the youngest climatic phase characterized by the presence of some calcareous specimens too. This may indicate a deeper Carbonate Compensation Depth, probably due to relatively stable and warmer environmental conditions. Results document that diversity of benthic foraminifera, number of specimens and variations in test morphology are related to regional differences in water properties (temperature, salinity, carbonate chemistry).
Bertoni, E.; Bertello, L.; Capotondi, L.; Bergami, C.; Giglio, F.; Ravaioli, M.; Rossi, C.; Ferretti, A.
Several research efforts that will contribute to assessment and monitoring of neotropical migratory birds are described, including: ) the use of neotropical migrants in the Environmental Monitoring and Assessment Program (EMAP) as potential indicators of general environmental con...
Scale decisions can reverse conclusions on community assembly processes
Aim Phylogenetic diversity patterns are increasingly being used to better understand the role of ecological and evolutionary processes in community assembly. Here, we quantify how these patterns are influenced by scale choices in terms of spatial and environmental extent and organismic scales. Location European Alps. Methods We applied 42 sampling strategies differing in their combination of focal scales. For each resulting sub-dataset, we estimated the phylogenetic diversity of the species pools, phylogenetic ?-diversities of local communities, and statistics commonly used together with null models in order to infer non-random diversity patterns (i.e. phylogenetic clustering versus over-dispersion). Finally, we studied the effects of scale choices on these measures using regression analyses. Results Scale choices were decisive for revealing signals in diversity patterns. Notably, changes in focal scales sometimes reversed a pattern of over-dispersion into clustering. Organismic scale had a stronger effect than spatial and environmental extent. However, we did not find general rules for the direction of change from over-dispersion to clustering with changing scales. Importantly, these scale issues had only a weak influence when focusing on regional diversity patterns that change along abiotic gradients. Main conclusions Our results call for caution when combining phylogenetic data with distributional data to study how and why communities differ from random expectations of phylogenetic relatedness. These analyses seem to be robust when the focus is on relating community diversity patterns to variation in habitat conditions, such as abiotic gradients. However, if the focus is on identifying relevant assembly rules for local communities, the uncertainty arising from a certain scale choice can be immense. In the latter case, it becomes necessary to test whether emerging patterns are robust to alternative scale choices.
Munkemuller, Tamara; Gallien, Laure; Lavergne, Sebastien; Renaud, Julien; Roquet, Cristina; Abdulhak, Sylvain; Dullinger, Stefan; Garraud, Luc; Guisan, Antoine; Lenoir, Jonathan; Svenning, Jens-Christian; Van Es, Jeremie; Vittoz, Pascal; Willner, Wolfgang; Wohlgemuth, Thomas; Zimmermann, Niklaus E.; Thuiller, Wilfried
Environmental conditions influence egg color of reed warblers Acrocephalus scirpaceus and their parasite, the common cuckoo Cuculus canorus
The outer layer of the eggshell in birds is in many cases covered by pigments that are assumed to be genetically determined\\u000a traits with a negligible environmental component. To test the hypothesis that spring environmental conditions (i.e., temperature\\u000a and rainfall) may affect bird egg pigmentation, we measured by spectrophotometry and photography egg coloration and spottiness\\u000a on reed warbler (Acrocephalus scirpaceus
Jesķs M. Avilťs; BŚrd G. Stokke; Arne Moksnes; Eivin RÝskaft; Anders P. MÝller
Holocene environmental conditions in South Georgia - a multi-proxy study on a coastal marine record
NASA Astrophysics Data System (ADS)
The Holocene environmental history of the sub-Antarctic island of South Georgia so far has been reconstructed from lake sediments, peat records and geomorphological observations. The data available indicate a postglacial ice retreat, which reached the coastal areas around the early Holocene. Climate reconstructions for the Holocene, on the other hand, provide a more complex picture, which may partly result from the influence of local effects. We present preliminary results of a multi-proxy study on a sediment core recovered in early 2013 from a coastal marine inlet (Little Jason Lagoon) in Cumberland West Bay. The results include elemental data (high resolution XRF-scans, total organic carbon (TOC), nitrogen, and sulphur, lipid biomarkers, and macrofossil data. The sediment core comprises a c. 11m long sequence, which contains a complete record of postglacial sedimentation in the inlet. Its base is formed by a diamicton, indicating a former glaciation of the site, which is overlain by well-stratified sediments passing over into more massive muds in the upper past. A radiocarbon age from the organic-rich sediments above the diamicton provides a first estimate of 9700 14C years BP for a minimum age of ice retreat. We use the elemental data to infer changes in clastic input (e.g., K/Ti ratios), productivity (TOC) and water salinity (Cl counts) in the course of the Holocene. While Little Jason Lagoon has a connection to the sea today (sill depth c. 1 m), a decrease in Cl counts downcore points to fresher conditions in the early part of the record. This could be an indicator for changing relative sea level and/or changes in the amounts of freshwater inflow from the catchment. Macroscopic plant remains and lipid biomarkers (n-alkanes, n-fatty acids and sterols) provide information on the terrestrial vegetation in the catchment and its changes through time as well as on the influence of marine conditions in the lagoon. We suggest that the record from Little Jason Lagoon provides an important link between terrestrial and marine archives of Holocene environmental change in South Georgia.
Berg, Sonja; Jivcov, Sandra; Groten, Sonja; Viehberg, Finn; Rethemeyer, Janet; Melles, Martin
Environmental Conditioning of Skeletal Anomalies Typology and Frequency in Gilthead Seabream (Sparus aurata L., 1758) Juveniles
In this paper, 981 reared juveniles of gilthead seabream (Sparus aurata) were analysed, 721 of which were from a commercial hatchery located in Northern Italy (Venice, Italy) and 260 from the Hellenic Center for Marine Research (Crete, Greece). These individuals were from 4 different egg batches, for a total of 10 different lots. Each egg batch was split into two lots after hatching, and reared with two different methodologies: intensive and semi-intensive. All fish were subjected to processing for skeletal anomaly and meristic count analysis. The aims involved: (1) quantitatively and qualitatively analyzing whether differences in skeletal elements arise between siblings and, if so, what they are; (2) investigating if any skeletal bone tissue/ossification is specifically affected by changing environmental rearing conditions; and (3) contributing to the identification of the best practices for gilthead seabream larval rearing in order to lower the deformity rates, without selections. The results obtained in this study highlighted that: i) in all the semi-intensive lots, the bones having intramembranous ossification showed a consistently lower incidence of anomalies; ii) the same clear pattern was not observed in the skeletal elements whose ossification process requires a cartilaginous precursor. It is thus possible to ameliorate the morphological quality (by reducing the incidence of severe skeletal anomalies and the variability in meristic counts of dermal bones) of reared seabream juveniles by lowering the stocking densities (maximum 16 larvae/L) and increasing the volume of the hatchery rearing tanks (minimum 40 m3). Feeding larvae with a wide variety of live (wild) preys seems further to improve juvenile skeletal quality. Additionally, analysis of the morphological quality of juveniles reared under two different semi-intensive conditions, Mesocosm and Large Volumes, highlighted a somewhat greater capacity of Large Volumes to significantly augment the gap with siblings reared in intensive (conventional) modality.
Prestinicola, Loredana; Boglione, Clara; Makridis, Pavlos; Spano, Attilio; Rimatori, Valentina; Palamara, Elisa; Scardi, Michele; Cataudella, Stefano
Simulation of the environmental climate conditions on martian surface and its effect on Deinococcus radiodurans
NASA Astrophysics Data System (ADS)
The resistance of terrestrial microorganisms under the thermo-physical conditions of Mars (diurnal temperature variations, UV climate, atmospheric pressure and gas composition) at mid-latitudes was studied for the understanding and assessment of potential life processes on Mars. In order to accomplish a targeted search for life on other planets, e.g. Mars, it is necessary to know the limiting physical and chemical parameters of terrestrial life. Therefore the polyextremophile bacterium Deinococcus radiodurans was chosen as test organism for these investigations. For the simulation studies at the Planetary and Space Simulation Facilities (PSI) at DLR, Cologne, Germany, conditions that are present during the southern summer at latitude of 60į on Mars were applied. We could simulate several environmental parameters of Mars in one single experiment: vacuum/low pressure, anoxic atmosphere and diurnal cycles in temperature and relative humidity, energy-rich ultraviolet (UV) radiation as well as shielding by different martian soil analogue materials. These parameters have been applied both single and in different combinations in laboratory experiments. Astonishingly the diurnal Mars-like cycles in temperature and relative humidity affected the viability of D. radiodurans cells quite severely. But the martian UV climate turned out to be the most deleterious factor, though D. radiodurans is red-pigmented due to carotenoids incorporated in its cell wall, which have been assigned not only a possible role as free radical scavenger but also as a UV-protectant. An additional UV-protection was accomplished by mixing the bacteria with nano-sized hematite.
de la Vega, U. Pogoda; Rettberg, P.; Reitz, G.
Dependence of Cumulus Anvil Radiative Properties on Environmental Conditions in the Tropical West Pacific
NASA Technical Reports Server (NTRS)
Areally extensive, optically thick anvil clouds associated with mesoscale convective clusters dominate the shortwave cloud forcing in the tropics and provide longwave forcing comparable to that of thin cirrus. Changes in the cover and optical thickness of tropical anvils as climate warms can regulate the sign of cloud feedback. As a prelude to the study of MMCR data from the ARM TWP sites, we analyze ISCCP-derived radiative characteristics of anvils observed in the tropical west Pacific during the TOGA-COARE IOP. Anvils with radius greater than 100 km were identified and tracked from inception to decay using the Machado-Rossow algorithm. Corresponding environmental conditions just prior to the start of the convectove event were diagnosed using the Lin-Johnson objective analysis product. Small clusters (100-200 km radius) are observed to have a broad range of optical thicknesses (10-50), while intermediate optical thickness clusters are observed to range in size from 100 km to almost 1000 km. Large-size clusters appear to be favored by strong pre-storm large scale upward motion throughout the troposphere, moist low-to-midlevel relative humidities, environments with slightly higher CAPE than those for smaller clusters, and strong front-to-rear flow. Optically thick anvils are favored in situations of strong low-level moisture convergence and strong upper-level shear.
Ye, B.; DelGenio, A. D.
Environmental conditions affecting exopolysaccharide production by Pseudomonas aeruginosa, Micrococcus sp., and Ochrobactrum sp.
Three different chromium-resistant microorganisms (Pseudomonas aeruginosa, Micrococcus sp., and Ochrobactrum sp.) were tested with regard to their EPS production at different pH levels, temperatures, Cr(VI) concentrations, and incubation periods. The optimum pH level was 7 for P. aeruginosa and Micrococcus sp., while it was 8 for Ochrobactrum sp. according to the highest EPS amount at 100 mg/L Cr(VI) concentration. The highest production of EPSs by the three bacteria was obtained under different environmental conditions. P. aeruginosa produced the highest EPS (863.3 mg/L) after incubation for 96 h on media with 50 mg/L Cr(VI) at 20 degrees C, Micrococcus sp. gave the highest yield (444.6 mg/L) after incubation for 72 h on media with 100 mg/L Cr(VI) at the same temperature, and Ochrobactrum sp. had the highest production (430.5 mg/L) on media with 150 mg/L Cr(VI) at 30 degrees C at the end of 48 h of incubation. PMID:18155834
KiliÁ, Nur KoÁberber; DŲnmez, GŲnŁl
Overview of environmental and hydrogeologic conditions at the Merle K. "Mudhole" Smith Airport near Cordova, Alaska
Air service to Cordova, Alaska and the surrounding region is provided by the Merle K. "Mudhole" Smith Airport, 21 kilometers east of the townsite. The Federal Aviation Administration owns or operates support facilities at the airport and wishes to consider the environmental setting and hydro- geologic conditions when evaluating options for remediation of potential contamination at these facilities. The airport is within the Copper River Delta wetlands area and the Chugach National Forest. Silts, sands, and gravels of fluvial origin underlie the airport. Potential flooding may be caused by outbursts of glacier-dammed lakes, glacier icemelt, snowmelt runoff, or precipitation. Surface spills and disposal of hazardous materials in conjunction with precipitation or flooding may adversely affect the quality of ground water. Drinking water at the airport is currently supplied by wells. Alternative drinking-water sources include local rivers and streams, transporting city water from Cordova, or undiscovered aquifers. Each alternative source, however, would likely cost significantly more to develop than using the existing shallow aquifer supply.
Dorava, J. M.; Sokup, J. M.
Toxicity of pentachlorophenol to aquatic organisms under naturally varying and controlled environmental conditions
The toxicity of pentachlorophenol (PCP) was determined in the laboratory for 11 aquatic species. Tests were conducted seasonally in ambient Mississippi River water and under controlled conditions in Lake Superior water. Fifty-one acute toxicity tests were conducted, with LC50 values ranging from 85 micrograms/L for the white sucker Catastomus commersoni during the summer to greater than 7770 micrograms/L for the isopod Asellus racovitzai during the winter. The effect of PCP on growth and/or reproduction was determined for seven species. The most sensitive chronically exposed organisms were the cladoceran Ceriodaphnia reticulata and the snail Physa gyrina. The greatest variation in toxicity was due to species sensitivity. Within a given, season there was as much as a 40-fold difference in LC50 values between species. For any one species, the maximum variation in LC50 between seasons was approximately 14-fold. There were also substantial differences in acute-chronic relationships, with acute/chronic ratios ranging from greater than 37 for C. reticulata to 1 for Simocephalus vetulus. It is suggested that the composition of the aquatic community should be the most important consideration in estimating the potential environmental effects of PCP.
Hedtke, S.F.; West, C.W.; Allen, K.N.; Norberg-King, T.J.; Mount, D.I.
Survival response of Bacteriovorax in surface biofilm versus suspension when stressed by extremes in environmental conditions.
The Bacteriovorax, previously in the genus Bdellovibrio, are prokaryotes that prey upon many Gram-negative bacteria. They are ubiquitous in salt-water environments and have been reported to have a strong association with biofilms. The purpose of this study was to test the hypothesis that this association affords protection for the Bacteriovorax and enhances their survival in nature when exposed to extreme environmental conditions. Experiments were designed to compare their survival in biofilms versus in suspension when exposed to extremes in salinity and temperature. Natural mixed-population biofilms generated in moderate-salinity (16 per thousand) Patuxent River water and containing Bacteriovorax were exposed to drastic changes in salinity by placing in low-salinity (1 per thousand) river water and salt-free (no measurable salinity) distilled water for up to 14 days. In a separate trial, the biofilm was exposed to extremes in temperature, 5 degrees C and 35 degrees C, for up to 12 weeks in aquarium mesocosms. Simultaneously, suspensions of the Bacteriovorax were exposed to the same extremes in salinity and temperature as biofilms. The results revealed that the Bacteriovorax typically were able to survive for a week or longer while in association with biofilms than when in suspension. These results are consistent with observations from nature and establish that biofilms are important in the survival and ecology of the Bacteriovorax. PMID:19267151
Williams, Henry N; Turng, Been-Foo; Kelley, Jacqueline I
Natal dispersal driven by environmental conditions interacting across the annual cycle of a migratory songbird
Natal dispersal, the process through which immature individuals permanently depart their natal area in search of new sites, is integral to the ecology and evolution of animals. Insights about the underlying causes of natal dispersal arise mainly from research on species whose short dispersal distances or restricted distributions make them relatively easy to track. However, for small migratory animals, the causes of natal dispersal remain poorly understood because individuals are nearly impossible to track by using conventional markĖrecapture approaches. Using stable-hydrogen isotope ratios in feathers of American redstarts (Setophaga ruticilla) captured as immature birds and again as adults, we show that habitat use during the first tropical nonbreeding season appears to interact with latitudinal gradients in spring phenology on the temperate breeding grounds to influence the distance traveled on the initial spring migration and the direction of natal dispersal. In contrast, adult redstarts showed considerable site fidelity between breeding seasons, indicating that environmental conditions did not affect dispersal patterns after the first breeding attempt. Our findings suggest that habitat occupancy during the first nonbreeding season helps determine the latitude at which this species of NeotropicalĖNearctic migratory bird breeds throughout its life and emphasize the need to understand how events throughout the annual cycle interact to shape fundamental biological processes.
Studds, Colin E.; Kyser, T. Kurt; Marra, Peter P.
Environmental conditions in near-wall plasmas generated by impact of energetic particle fluxes
NASA Astrophysics Data System (ADS)
Directional flows of energetic ions produced by laser-exploded foils were used to investigate transient phenomena accompanying the plasma interaction with surfaces of solid targets (walls). In experiments carried out on the iodine laser system PALS, the formation of energetic plasma jets from burn-through foils of Al and Ta was optimized using the three-frame interferometry and applied to a design of alternate experimental configurations. The interaction of the directional plasma flows with secondary targets was studied via X-ray imaging, optical and high-resolution X-ray spectroscopy. The environmental conditions in near-wall plasmas created at surfaces of plasma-exposed solids, in particular the velocity distribution of impinging and back-scattered ions, were determined via analysis of the observed spatially-resolved spectra of Al Ly? and He? groups. The validity of the ion velocity gradients derived from the Doppler effect induced shifts and splitting of the spectral lines was supported by theoretical modeling based on a combination of hydrodynamic, atomic and collisional-radiative codes.
Renner, O.; ämŪd, M.; Burian, T.; Juha, L.; KrŠsa, J.; Krouskż, E.; MatulkovŠ, I.; SkŠla, J.; Velyhan, A.; Liska, R.; Velechovskż, J.; Pisarczyk, T.; Chodukowski, T.; Larroche, O.; Ullschmied, J.
Interactions between clay portions with various contacts and subjected to specific environmental conditions
NASA Astrophysics Data System (ADS)
So far clays have always been considered, both experimentally and theoretically, as ideally flat and under arbitrary orientations. The goal here is to shed light on the different cases of possible contact between portions of clay, which will be subject to peculiar conditions of temperature and pressure. To this end, molecular dynamics study has been performed to investigate the evolution of nonparallel hydrated Wyoming-type Na-montmorillonite. In the present work, we study two clay structures containing two then three nonparallel portions. The contact manners between each other are considered as point and/or edge. We show that under the effect of environmental constraints, the dihedral angle of the horizontal and inclined portions tend to shrink; at the same time, the clay layers of inclined portions have a tendency to rotate. Due to this rotation, the contact of point can be considered as the evolution of the contact of edge. With the presence of water, the layers of inclined clay portions turn in different ways. The temperature effect is negligible, but the pressure plays an important role on the behaviour of clay layers.
Zheng, Y.; Zaoui, A.; Pasteau, A.
Variation of saponin contents and physiological status in Quillaja saponaria under different environmental conditions.
Quillaja saponaria (Quillay), an evergreen tree found in Chile, is one of the main sources of saponins. Quillaja saponins have hypocholesterolaemic, anticarcinogenic, antioxidant and pesticidal properties, and are used as adjuvants for vaccines. Samples of Quillay growing at three zones in O'Higgins Region, Chile (Coastal, Central and Mountain zones) were analyzed for content of saponins and physiological status. The results revealed differences in the content of saponins depending on the zone of sample collection. The highest contents were found in samples from the Mountain zone, where the highest saponin contents were accompanied by the lowest foliar nitrogen contents, the highest antioxidant activity and the highest carotenoid contents. The results suggest a physiological and adaptive mechanism of saponins in plants to survive under unfavourable environmental conditions. The results have important implications for a theoretical basis for the design of a reasonable harvest, to avoid the cost of poor quality material, and also to provide a sustainable use and conservation of this important species. Further research on the effects of stress will improve our understanding of the saponins production and their physiological functions in plants, whereas they have generally been studied for their biological and chemical applications. PMID:24555275
Grandůn, Angťlica S; Espinosa, B Miguel; RŪos, Darcy L; SŠnchez, O Manuel; SŠez, C Katia; HernŠndez, S VŪctor; Becerra, A Josť
IGF-1 release kinetics from chitosan microparticles fabricated using environmentally benign conditions.
The main objective of this study is to maximize growth factor encapsulation efficiency into microparticles. The novelty of this study is to maximize the encapsulated growth factors into microparticles by minimizing the use of organic solvents and using relatively low temperatures. The microparticles were fabricated using chitosan biopolymer as a base polymer and cross-linked with tripolyphosphate (TPP). Insulin like-growth factor-1 (IGF-1) was encapsulated into microparticles to study release kinetics and bioactivity. In order to authenticate the harms of using organic solvents like hexane and acetone during microparticle preparation, IGF-1 encapsulated microparticles prepared by the emulsification and coacervation methods were compared. The microparticles fabricated by emulsification method have shown a significant decrease (p<0.05) in IGF-1 encapsulation efficiency, and cumulative release during the two-week period. The biocompatibility of chitosan microparticles and the bioactivity of the released IGF-1 were determined in vitro by live/dead viability assay. The mineralization data observed with von Kossa assay, was supported by mRNA expression levels of osterix and runx2, which are transcription factors necessary for osteoblasts differentiation. Real time RT-PCR data showed an increased expression of runx2 and a decreased expression of osterix over time, indicating differentiating osteoblasts. Chitosan microparticles prepared in optimum environmental conditions are a promising controlled delivery system for cells to attach, proliferate, differentiate and mineralize, thereby acting as a suitable bone repairing material. PMID:25063148
Mantripragada, Venkata P; Jayasuriya, Ambalangodage C
Infrared Spectroscopy of Pollen Identifies Plant Species and Genus as Well as Environmental Conditions
Background It is imperative to have reliable and timely methodologies for analysis and monitoring of seed plants in order to determine climate-related plant processes. Moreover, impact of environment on plant fitness is predominantly based on studies of female functions, while the contribution of male gametophytes is mostly ignored due to missing data on pollen quality. We explored the use of infrared spectroscopy of pollen for an inexpensive and rapid characterization of plants. Methodology The study was based on measurement of pollen samples by two Fourier transform infrared techniques: single reflectance attenuated total reflectance and transmission measurement of sample pellets. The experimental set, with a total of 813 samples, included five pollination seasons and 300 different plant species belonging to all principal spermatophyte clades (conifers, monocotyledons, eudicots, and magnoliids). Results The spectroscopic-based methodology enables detection of phylogenetic variations, including the separation of confamiliar and congeneric species. Furthermore, the methodology enables measurement of phenotypic plasticity by the detection of inter-annual variations within the populations. The spectral differences related to environment and taxonomy are interpreted biochemically, specifically variations of pollen lipids, proteins, carbohydrates, and sporopollenins. The study shows large variations of absolute content of nutrients for congenital species pollinating in the same environmental conditions. Moreover, clear correlation between carbohydrate-to-protein ratio and pollination strategy has been detected. Infrared spectral database with respect to biochemical variation among the range of species, climate and biogeography will significantly improve comprehension of plant-environment interactions, including impact of global climate change on plant communities.
Zimmermann, Boris; Kohler, Achim
Non-coding RNAs in marine Synechococcus and their regulation under environmentally relevant stress conditions
Regulatory small RNAs (sRNAs) have crucial roles in the adaptive responses of bacteria to changes in the environment. Thus far, potential regulatory RNAs have been studied mainly in marine picocyanobacteria in genetically intractable Prochlorococcus, rendering their molecular analysis difficult. Synechococcus sp. WH7803 is a model cyanobacterium, representative of the picocyanobacteria from the mesotrophic areas of the ocean. Similar to the closely related Prochlorococcus it possesses a relatively streamlined genome and a small number of genes, but is genetically tractable. Here, a comparative genome analysis was performed for this and four additional marine Synechococcus to identify the suite of possible sRNAs and other RNA elements. Based on the prediction and on complementary microarray profiling, we have identified several known as well as 32 novel sRNAs. Some sRNAs overlap adjacent coding regions, for instance for the central photosynthetic gene psbA. Several of these novel sRNAs responded specifically to environmentally relevant stress conditions. Among them are six sRNAs changing their accumulation level under cold stress, six responding to high light and two to iron limitation. Target predictions suggested genes encoding components of the light-harvesting apparatus as targets of sRNAs originating from genomic islands and that one of the iron-regulated sRNAs might be a functional homolog of RyhB. These data suggest that marine Synechococcus mount adaptive responses to these different stresses involving regulatory sRNAs.
Gierga, Gregor; Voss, Bjorn; Hess, Wolfgang R
Non-coding RNAs in marine Synechococcus and their regulation under environmentally relevant stress conditions.
Regulatory small RNAs (sRNAs) have crucial roles in the adaptive responses of bacteria to changes in the environment. Thus far, potential regulatory RNAs have been studied mainly in marine picocyanobacteria in genetically intractable Prochlorococcus, rendering their molecular analysis difficult. Synechococcus sp. WH7803 is a model cyanobacterium, representative of the picocyanobacteria from the mesotrophic areas of the ocean. Similar to the closely related Prochlorococcus it possesses a relatively streamlined genome and a small number of genes, but is genetically tractable. Here, a comparative genome analysis was performed for this and four additional marine Synechococcus to identify the suite of possible sRNAs and other RNA elements. Based on the prediction and on complementary microarray profiling, we have identified several known as well as 32 novel sRNAs. Some sRNAs overlap adjacent coding regions, for instance for the central photosynthetic gene psbA. Several of these novel sRNAs responded specifically to environmentally relevant stress conditions. Among them are six sRNAs changing their accumulation level under cold stress, six responding to high light and two to iron limitation. Target predictions suggested genes encoding components of the light-harvesting apparatus as targets of sRNAs originating from genomic islands and that one of the iron-regulated sRNAs might be a functional homolog of RyhB. These data suggest that marine Synechococcus mount adaptive responses to these different stresses involving regulatory sRNAs. PMID:22258101
Gierga, Gregor; Voss, BjŲrn; Hess, Wolfgang R
30 CFR 585.816 - What must I do if environmental or other conditions adversely affect a cable, pipeline, or facility?
Code of Federal Regulations, 2013 CFR
...conditions adversely affect a cable, pipeline, or facility? 585.816 Section...conditions adversely affect a cable, pipeline, or facility? If environmental or other conditions adversely affect a cable, pipeline, or facility so as to endanger the...
Degradation kinetics of levoglucosan initiated by hydroxyl radical under different environmental conditions
NASA Astrophysics Data System (ADS)
To understand the atmospheric stability of levoglucosan, which is a major molecular tracer used for source apportionment of biomass burning aerosols, degradation kinetics of levoglucosan by hydroxyl radical (OH) have been investigated using a flow reactor under different conditions. The second-order rate constant (k2) for the degradation of pure levoglucosan by OH is (9.17†Ī†1.16)†◊†10-12†cm3†molecules-1†s-1 at 25†įC and 40% relative humidity (RH), while it depends on environmental conditions such as temperature, RH,†and mixing state. At 25†įC, k2 of pure levoglucosan linearly decreases with increasing RH (k2†=†(1.50†Ī†0.04)†◊†10-11†-†(1.31†Ī†0.11)†◊†10-11RH), while it increases with increasing temperature and follows the Arrhenius equation k2†=†(6.2†Ī†5.6)†◊†10-9exp[(-1922.5†Ī†268.2)/T] when the RH is 40%. At 25†įC and 40% RH, compared to pure levoglucosan, levoglucosan coated on (NH4)2SO4 or NaCl (levoglucosan@(NH4)2SO4 and levoglucosan@NaCl) shows larger k2 to OH with (9.53†Ī†0.39)†◊†10-12 and (10.3†Ī†0.45)†◊†10-12†cm3†molecules-1†s-1, respectively, whereas levoglucosan coated on soot (levoglucosan@soot) shows the smaller k2 of (4.04†Ī†0.29)†◊†10-12†cm3†molecules-1†s-1. Either (NH4)2SO4 or NaCl internally mixed with levoglucosan ((NH4)2SO4@levoglucosan and NaCl@levoglucosan) prominently inhibits the degradation of levoglucosan. Based on the rate constants, atmospheric lifetimes of levoglucosan were estimated to be 1.2-3.9 days under different conditions. All the results indicate that the degradation of levoglucosan by OH is prominent during air mass aging, and it should have an important influence on the uncertainty of source apportionment if the contribution of degradation to levoglucosan concentration is not considered in source apportionment models.
Lai, Chengyue; Liu, Yongchun; Ma, Jinzhu; Ma, Qingxin; He, Hong
Feasibility of fiber Bragg grating and long-period fiber grating sensors under different environmental conditions.
This paper presents the feasibility of utilizing fiber Bragg grating (FBG) and long-period fiber grating (LPFG) sensors for nondestructive evaluation (NDE) of infrastructures using Portland cement concretes and asphalt mixtures for temperature, strain, and liquid-level monitoring. The use of hybrid FBG and LPFG sensors is aimed at utilizing the advantages of two kinds of fiber grating to implement NDE for monitoring strains or displacements, temperatures, and water-levels of infrastructures such as bridges, pavements, or reservoirs for under different environmental conditions. Temperature fluctuation and stability tests were examined using FBG and LPFG sensors bonded on the surface of asphalt and concrete specimens. Random walk coefficient (RWC) and bias stability (BS) were used for the first time to indicate the stability performance of fiber grating sensors. The random walk coefficients of temperature variations between FBG (or LPFG) sensor and a thermocouple were found in the range of -0.7499 įC/ [square root]h to -1.3548 įC/ [square root]h. In addition, the bias stability for temperature variations, during the fluctuation and stability tests with FBG (or LPFG) sensors were within the range of 0.01 įC/h with a 15-18 h time cluster to 0.09 įC/h with a 3-4 h time cluster. This shows that the performance of FBG or LPFG sensors is comparable with that of conventional high-resolution thermocouple sensors under rugged conditions. The strain measurement for infrastructure materials was conducted using a packaged FBG sensor bonded on the surface of an asphalt specimen under indirect tensile loading conditions. A finite element modeling (FEM) was applied to compare experimental results of indirect tensile FBG strain measurements. For a comparative analysis between experiment and simulation, the FEM numerical results agreed with those from FBG strain measurements. The results of the liquid-level sensing tests show the LPFG-based sensor could discriminate five stationary liquid-levels and exhibits at least 1,050-mm liquid-level measurement capacity. Thus, the hybrid FBG and LPFG sensors reported here could benefit the NDE development and applications for infrastructure health monitoring such as strain, temperature and liquid-level measurements. PMID:22163460
Wang, Jian-Neng; Tang, Jaw-Luen
Morphology of biogenic iron oxides records microbial physiology and environmental conditions: toward interpreting iron microfossils.
Despite the abundance of Fe and its significance in Earth history, there are no established robust biosignatures for Fe(II)-oxidizing micro-organisms. This limits our ability to piece together the history of Fe biogeochemical cycling and, in particular, to determine whether Fe(II)-oxidizers played a role in depositing ancient iron formations. A promising candidate for Fe(II)-oxidizer biosignatures is the distinctive morphology and texture of extracellular Fe(III)-oxyhydroxide stalks produced by mat-forming microaerophilic Fe(II)-oxidizing micro-organisms. To establish the stalk morphology as a biosignature, morphologic parameters must be quantified and linked to the microaerophilic Fe(II)-oxidizing metabolism and environmental conditions. Toward this end, we studied an extant model organism, the marine stalk-forming Fe(II)-oxidizing bacterium, Mariprofundus ferrooxydans PV-1. We grew cultures in flat glass microslide chambers, with FeS substrate, creating opposing oxygen/Fe(II) concentration gradients. We used solid-state voltammetric microelectrodes to measure chemical gradients in situ while using light microscopy to image microbial growth, motility, and mineral formation. In low-oxygen (2.7-28†?m) zones of redox gradients, the bacteria converge into a narrow (100†?m-1†mm) growth band. As cells oxidize Fe(II), they deposit Fe(III)-oxyhydroxide stalks in this band; the stalks orient directionally, elongating toward higher oxygen concentrations. M.†ferrooxydans stalks display a narrow range of widths and uniquely biogenic branching patterns, which result from cell division. Together with filament composition, these features (width, branching, and directional orientation) form a physical record unique to microaerophilic Fe(II)-oxidizer physiology; therefore, stalk morphology is a biosignature, as well as an indicator of local oxygen concentration at the time of formation. Observations of filamentous Fe(III)-oxyhydroxide microfossils from a ~170†Ma marine Fe-Si hydrothermal deposit show that these morphological characteristics can be preserved in the microfossil record. This study demonstrates the potential of morphological biosignatures to reveal microbiology and environmental chemistry associated with geologic iron formation depositional processes. PMID:23790206
Krepski, S T; Emerson, D; Hredzak-Showalter, P L; Luther, G W; Chan, C S
Fine-scale spatial variation in plant species richness and its relationship to environmental conditions in coastal marshlands
Previous studies have shown that variations in environmental conditions play a major role in explaining variations in plant species richness at community and landscape scales. In this study, we considered the degree to which fine-scale spatial variations in richness could be related to fine-scale variations in abiotic and biotic factors. To examine spatial variation in richness, grids of 1 m(2) plots were laid out at five sites within a coastal riverine wetland landscape. At each site, a 5 x 7 array of plots was established adjacent to the river's edge with plots one meter apart. In addition to the estimation of species richness, environmental measurements included sediment salinity, plot microelevation, percent of plot recently disturbed, and estimated community biomass. Our analysis strategy was to combine the use of structural equation modeling (path modeling) with an assessment of spatial association. Mantel's tests revealed significant spatial autocorrelation in species richness at four of the five sites sampled, indicating that richness in a plot correlated with the richness of nearby plots. We subsequently considered the degree to which spatial autocorrelations in richness could be explained by spatial autocorrelations in environmental conditions. Once data were corrected for environmental correlations, spatial autocorrelation in residual species richness could not be detected at any site. Based on these results, we conclude that in this coastal wetland, there appears to be a fine-scale mapping of diversity to microgradients in environmental conditions.
Mancera, J.E.; Meche, G.C.; Cardona-Olarte, P.P.; Castaneda-Moya, E.; Chiasson, R.L.; Geddes, N.A.; Schile, L.M.; Wang, H.G.; Guntenspergen, G.R.; Grace, J.B.
Effect of Environmental Conditions of Abu-Zabal Lake on Some Biological, Histological and Quality Aspects of Fish
3 Abstract: The purpose of this work was to investigate the effect of environmental conditions of Abu-Zabal Lake on fish caught during March, 2005 till February, 2006. The biological, histological and quality aspects were monitored. Species composition; length-weight relation; condition factor; length-scale relation and growth in length of four cichlid species were studied. Also, histopathological alterations for testis and gills
S. M. Ibrahim; K. A. Sh; H. M. Salama
Environmental conditions at the South Col of Mount Everest and their impact on hypoxia and hypothermia experienced by mountaineers
Background Hypoxia and hypothermia are acknowledged risk factors for those who venture into high-altitude regions. There is, however, little in situ data that can be used to quantify these risks. Here, we use 7?months of continuous meteorological data collected at the South Col of Mount Everest (elevation 7,896?m above sea level) to provide the first in situ characterization of these risks near the summit of Mount Everest. Methods This is accomplished through the analysis of barometric pressure, temperature and wind speed data collected by an automatic weather station installed at the South Col. These data were also used as inputs to parameterizations of wind chill equivalent temperature (WCT) and facial frostbite time (FFT). Results The meteorological data show clear evidence of seasonality, with evidence of pre-monsoon, monsoon and post-monsoon conditions. Low pressures, cold temperatures and high wind speeds characterize the pre- and post-monsoon periods with significant variability associated with the passage of large-scale weather systems. In contrast, the monsoon period is characterized by higher pressures, warmer temperatures and lower wind speeds with a pronounced reduction in variability. These environmental conditions are reflected in WCTs as low as ?50įC and FFTs as short as 2?min during the pre- and post-monsoon periods. During the monsoon, the risk of cold injury is reduced with WCTs of order ?20įC and FFTs longer than 60?min. The daily cycle in the various parameters is also investigated in order to assess the changes in conditions that would be experienced during a typical summit day. The post-monsoon period in particular shows a muted daily cycle in most parameters that is proposed to be the result of the random timing of large-scale weather systems. Conclusions Our results provide the first in situ characterization of the risk of hypoxia and hypothermia on Mount Everest on daily, weekly and seasonal timescales, and provide additional confirmation as to the extreme environment experienced by those attempting to summit Mount Everest and other high Himalayan mountains.
Chemical and Physical Environmental Conditions Underneath Mat and Canopy-Forming Macroalgae, and Their Effects on Understorey Corals
Disturbed coral reefs are often dominated by dense mat- or canopy-forming assemblages of macroalgae. This study investigated how such dense macroalgal assemblages change the chemical and physical microenvironment for understorey corals, and how the altered environmental conditions affect the physiological performance of corals. Field measurements were conducted on macroalgal-dominated inshore reefs in the Great Barrier Reef in quadrats with macroalgal
Claudine Hauri; Katharina E. Fabricius; Britta Schaffelke; Craig Humphrey; Stuart Humphries
Characterization of condenser microphones under different environmental conditions for accurate speed of sound measurements with acoustic resonators
Condenser microphones are more commonly used and have been extensively modeled and characterized in air at ambient temperature and static pressure. However, several applications of interest for metrology and physical acoustics require to use these transducers in significantly different environmental conditions. Particularly, the extremely accurate determination of the speed of sound in monoatomic gases, which is pursued for a determination
Cťcile Guianvarc'h; Roberto M. Gavioso; Giuliana Benedetto; Laurent Pitre; Michel Bruneau
The comparative effectiveness of some psychological and physiological measures in ranking the impact of diverse environmental conditions
Two studies are presented, both of which compare the effectiveness of a subjective rating scale with two physiological measures, mean weighted skin temperature and average increase in metabolic rate, in ranking eight environmental conditions (varying in ambient temperature, humidity and wind speed) from warmest to coldest. The results† indicate a high degree of consistency between individual responses on each measure
Bernard J. Fine
Molecular evolution of the hyperthermophilic archaea of the Pyrococcus genus: analysis of adaptation to different environmental conditions
BACKGROUND: Prokaryotic microorganisms are able to survive and proliferate in severe environmental conditions. The increasing number of complete sequences of prokaryotic genomes has provided the basis for studying the molecular mechanisms of their adaptation at the genomic level. We apply here a computer-based approach to compare the genomes and proteomes from P. furiosus, P. horikoshii, and P. abyssi to identify
Konstantin V. Gunbin; Dmitry A. Afonnikov; Nikolay A. Kolchanov
Characterisation of photovoltaic modules based on thin film solar cells in environmental operating conditions of Algerian Sahara
This paper summarizes the electrical and thermal characterizations of thin film PV modules based on amorphous triple junctions (3J: a-Si) and Copper Indium Selenide (CIS) thin film solar cells. Tests are operated in outdoor exposure and under natural sunlight of Ghardaia (Algeria) as specific desert climate environment, characterized by high irradiation and temperature levels. Data acquired from Environmental Operating Conditions
K. Agroui; I. Hadj Mahammed; A. Hadj Arab; A. Belghachi
The role of quorum sensing and the effect of environmental conditions on biofilm formation by strains of Vibrio vulnificus
It has been suggested that Vibrio vulnificus attaches to plankton and algae and is found in large numbers in the environment. Factors affecting attachment, biofilm formation and morphology of V. vulnificus have not been thoroughly investigated. This study evaluated the role of quorum sensing (QS) and environmental conditions on biofilm development of V. vulnificus. It was found that biofilm development
D. McDougald; W. H. Lin; S. A. Rice; S. Kjelleberg
Lubricity effect of carbon dioxide used as an environmentally friendly refrigerant in air-conditioning and refrigeration compressors
Environmental concerns have increased the interest in alternative natural refrigerants for air-conditioning and refrigeration compressors. Carbon dioxide (CO2) or R744 is an attractive candidate to replace harmful hydrofluorocarbon refrigerants, which will need to be replaced in the near future due to their high global warming potential. In this paper the tribological behavior of gray cast iron in the presence of
Emerson Escobar Nunez; Kyriaki Polychronopoulou; Andreas A. Polycarpou
Development of crystalline peroxisomes in methanol-grown cells of the yeast Hansenula polymorpha and its relation to environmental conditions
The development of peroxisomes has been studied in cells of the yeast Hansenula polymorpha during growth on methanol in batch and chemostat cultures. During bud formation, new peroxisomes were generated by the separation of small peroxisomes from mature organelles in the mother cells. The number of peroxisomes migrating to the buds was dependent upon environmental conditions. Aging of cells was
M. Veenhuis; J. P. van Dijken; S. A. F. Pilon; W. Harder
Environmental and pollution condition of the huizache-caimanero lagoon, in the north-west of Mexico
The fish and shrimp production of the Huizache-Caimanero Lagoon, located on the Mexican Pacific, has been decreasing in recent years, which may be due to environmental and pollution conditions. Therefore, water and sediment samples were analysed to quantify nutrients, pesticides, and coliform bacteria. The results indicated that the system is polluted considerably during the rainy season due to continental runoff
R. JosťGuillermo Galindo; J. MarŪa Alejandra Medina; L. Cecilio Villagrana; C. Leonardo Ibarra
Amoxicillin-degradation products formed under controlled environmental conditions: identification and determination in the aquatic environment.
Amoxicillin (AMX) is a widely used penicillin-type antibiotic whose presence in the environment has been widely investigated, despite its rapid hydrolysis to various degradation products (DPs). In this work, the formation of AMX DPs was studied in various aqueous solutions containing 100?gmL(-1) AMX. Three phosphate buffer solutions, at pH 5, pH 7 and pH 8, and a fourth buffer solution at pH 7 with the addition of the bivalent ions Mg(2+)and Ca(2) as chelating agents, were examined under controlled environmental conditions. In addition, two solutions from natural sources were examined secondary effluents and tap water. The obtained DPs were identified by their MS/MS, UV and NMR spectra (obtained from pure compounds isolated by preparative HPLC) as: AMX penicilloic acid (ADP1/2), AMX penilloic acid (ADP4/5) and phenol hydroxypyrazine (ADP6). Two additional detected DPs AMX 2',5'-diketopiperazine (ADP8/9), and AMX-S-oxide (ADP3) were reported and discussed in our previous publications. These DPs were then detected in secondary effluent and groundwater from a well located beneath agricultural fields continuously irrigated with secondary effluent. Concentrations in the secondary effluent were: ADP1/2, several micrograms per liter; ADP4/5, 0.15?gL(-1), and ADP8/9, 0.5?gL(-1). ADP6 were detected but not quantified. In the groundwater, only ADP8/9 was detected, at a concentration of 0.03?gL(-1). The detection and quantification of DPs of other investigated drugs is recommended as an integral part of any study, method or technique dealing with pharmaceutical residues in aquatic environments. PMID:23466086
Gozlan, Igal; Rotstein, Adi; Avisar, Dror
Weeks Island brine diffuser site study: baseline conditions and environmental assessment technical report
This technical report presents the results of a study conducted at two alternative brine diffuser sites (A and B) proposed for the Weeks Island salt dome, together with an analysis of the potential physical, chemical, and biological effects of brine disposal for this area of the Gulf of Mexico. Brine would result from either the leaching of salt domes to form or enlarge oil storage caverns, or the subsequent use of these caverns for crude oil storage in the Strategic Petroleum Reserve (SPR) program. Brine leached from the Weeks Island salt dome would be transported through a pipeline which would extend from the salt dome either 27 nautical miles (32 statute miles) for Site A, or 41 nautical miles (47 statute miles) for Site B, into Gulf waters. The brine would be discharged at these sites through an offshore diffuser at a sustained peak rate of 39 ft/sup 3//sec. The disposal of large quantities of brine in the Gulf could have a significant impact on the biology and water quality of the area. Physical and chemical measurements of the marine environment at Sites A and B were taken between September 1977 and July 1978 to correlate the existing environmental conditions with the estimated physical extent of tthe brine discharge as predicted by the MIT model (US Dept. of Commerce, 1977a). Measurements of wind, tide, waves, currents, and stratification (water column structure) were also obtained since the diffusion and dispersion of the brine plume are a function of the local circulation regime. These data were used to calculate both near- and far-field concentrations of brine, and may also be used in the design criteria for diffuser port configuration and verification of the plume model. Biological samples were taken to characterize the sites and to predict potential areas of impact with regard to the discharge. This sampling focused on benthic organisms and demersal fish. (DMC)
Relations between introduced fish and environmental conditions at large geographic scales
Data collected from 20 major river basins between 1993 and 1995 as part of the US Geological Survey's (USGS) National Water-Quality Assessment (NAWQA) Program were analyzed to assess patterns in introduced and native fish species richness and abundance relative to watershed characteristics and stream physicochemistry. Sites (N = 157) were divided into three regions-northeast, southeast, and west- to account for major longitudinal differences in precipitation/runoff and latitudinal limits of glaciation that affect zoogeographic patterns in fish communities. Common carp (Cyprinus carpio) and largemouth bass (Micropterus salmoides) were the most frequently collected introduced fish species across all river basins combined. Based on the percentage of introduced fish species, the fish communities most altered by the presence of introduced fish occurred in the western and northeastern parts of the US. Native fish species richness was not an indicator of introduced fish species richness for any of the three regions. However, in the west, introduced fish species richness was an indicator of total fish species richness and the abundance of introduced fish was negatively related to native fish species richness. Some relations between introduced fish species and environmental conditions were common between regions. Increased introduced fish species richness was related to increased population density in the northeast and southeast; increased total nitrogen in the northeast and west; and increased total phosphorous and water temperature in the southeast and west. These results suggest that introduced fish species tend to be associated with disturbance at large geographic scales, though specific relations may vary regionally. ?? 2003 Elsevier Science Ltd. All rights reserved.
Meador, M. R.; Brown, L. R.; Short, T.
Cold-water coral growth under extreme environmental conditions, the Cape Lookout area, NW Atlantic
NASA Astrophysics Data System (ADS)
The Cape Lookout cold-water coral area off the coast of North Carolina forms the shallowest and northernmost cold-water coral mound area on the Blake Plateau in the NW Atlantic. Cold-water coral habitats near Cape Lookout are occasionally bathed in the Gulf Stream, which is characterised by oligotrophic warm water and strong surface currents. Here, we present the first insights into the mound distribution and morphology, sedimentary environment and coral cover and near-bed environmental conditions as recorded by bottom landers from this coral area. The mounds occur between 320-550 m water depth and are characterised by high acoustic backscatter indicating the presence of hard structure. Three distinct mound morphologies were observed, (1) a mound with a flattened top at 320 m, (2) multi-summited mounds with a tear drop shape in the middle part of the area and (3) a single mound at 540 m water depth. Echosounder profiles show the presence of a strong reflector underneath all mound structures that forms the base of the mounds. This reflector cropped out at the downstream side of the single mound and consists of carbonate slabs. Video analysis revealed that all mounds are covered by Lophelia pertusa and that living colonies only occur close to the summits of the SSW side of the mounds, which is the side that faces the strongest currents. Off mound areas were characterised by low backscatter and sediment ripples, indicating the presence of relatively strong bottom currents. Two bottom landers were deployed amidst the coral mounds between December 2009 and May 2010. Both landers recorded prominent features near the seabed as well as in the overlying water column. The period between December and April was characterised by several events of increasing temperature and salinity, coinciding with increased flow and near-bed acoustic backscatter. During these events temperature fluctuated by up to 9 įC within a day, which is the largest temperature variability as measured so far in a cold-water coral habitat. Warm events, related to Gulf Stream meanders, had the duration of roughly one week and the current during these events was directed to the NNE. The consequences of such events must be significant given the strong effects of temperature on the metabolism of cold-water corals. Furthermore, elevated acoustic backscatter values and high mass fluxes were also recorded during these events, indicating a second stressor that may affect the corals. The abrasive nature of sand in combination with strong currents might sand blast the corals. We conclude that cold-water corals near Cape Lookout live under extreme conditions that limit mound growth at present.
Mienis, F.; Duineveld, G.; Davies, A. J.; Lavaleye, M. J. N.; Ross, S. W.; Seim, H.; Bane, J.; van Haren, H.; Bergman, M.; de Haas, H.; Brooke, S.; van Weering, T.
Cumulative impacts of coastline variation on hydrodynamic condition and environmental capacity of Jiaozhou Bay
This paper examines the definition and the generic typology of cumulative effects. The most important environmental problem caused by the development is the cumulative effects. Based on this theory, this paper selects Jiaozhou Bay as a typical coastal region, studies the cumulative effects on the hydrodynamic force environment and marine environmental capacity which caused by human reclaiming, and forecasts the
Jing Zhang; Guipeng Yang; Yi Tian
Long-term human response to uncertain environmental conditions in the Andes
Human interaction with the physical environment has increasingly transformed Earth-system processes. Reciprocally, climate anomalies and other processes of environmental change of natural and anthropogenic origin have been affecting, and often disrupting, societies throughout history. Transient impact events, despite their brevity, can have significant long-term impact on society, particularly if they occur in the context of ongoing, protracted environmental change. Major climate events can affect human activities in critical conjunctures that shape particular trajectories of social development. Here we report variable human responses to major environmental events in the Andes with a particular emphasis on the period from anno Domini 500Ė1500 on the desert north coast of Perķ. We show that preindustrial agrarian societies implemented distinct forms of anticipatory response to environmental change and uncertainty. We conclude that innovations in production strategies and agricultural infrastructures in these indigenous societies reflect differential social response to both transient (El NiŮoĖSouthern Oscillation events) and protracted (desertification) environmental change.
Dillehay, Tom D.; Kolata, Alan L.
Variety in cereal production in the Late Bronze and Early Iron Ages in relation to environmental conditions
NASA Astrophysics Data System (ADS)
The objective of this paper is to assess the relationship between the cereals cultivated in the Late Bronze and Early Iron Ages (ca. 1250 - 400 cal BC) on the territory of present day Czech Republic and their environmental settings. The representation of various charred cereal caryopses in the archaeobotanical assemblages from 35 archaeological sites differ, especially in the proportion of wheats and barley. The cereal assemblages were compared with a site altitude, weather conditions,soils and soil productivity. The most important environmental variable influencing the choice of a particular crop seem to be altitude associated with the length of growing season (afterwards the soil conditions). Although the ecological requirements of cereals cultivated in the Late Bronze and Early Iron Ages are not known, they presumably thrived under similar conditions to present day species/varieties and that the strategy of past crop husbandry was based on similar principles as today, e.g. the flexible adaptations to local environmental conditions in an effort to achieve optimal yields and to reduce the danger of crop failure.
Poniötiak, ätefan; DreslerovŠ, Dagmar; äefrna, Lud?k; Ko?Šr, Petr; Chuman, TomŠö
Use of response surface methodology to optimise environmental stress conditions on Penicillium glabrum, a food spoilage mould.
Fungi are ubiquitous microorganisms often associated with spoilage and biodeterioration of a large variety of foods and feedstuffs. Their growth may be influenced by temporary changes in intrinsic or environmental factors such as temperature, water activity, pH, preservatives, atmosphere composition, all of which may represent potential sources of stress. Molecular-based analyses of their physiological responses to environmental conditions would help to better manage the risk of alteration and potential toxicity of food products. However, before investigating molecular stress responses, appropriate experimental stress conditions must be precisely defined. Penicillium glabrum is a filamentous fungus widely present in the environment and frequently isolated in the food processing industry as a contaminant of numerous products. Using response surface methodology, the present study evaluated the influence of two environmental factors (temperature and pH) on P. glabrum growth to determine 'optimised' environmental stress conditions. For thermal and pH shocks, a large range of conditions was applied by varying factor intensity and exposure time according to a two-factorial central composite design. Temperature and exposure duration varied from 30 to 50 įC and from 10 min to 230 min, respectively. The effects of interaction between both variables were observed on fungal growth. For pH, the duration of exposure, from 10 to 230 min, had no significant effect on fungal growth. Experiments were thus carried out on a range of pH from 0.15 to 12.50 for a single exposure time of 240 min. Based on fungal growth results, a thermal shock of 120 min at 40 įC or a pH shock of 240 min at 1.50 or 9.00 may therefore be useful to investigate stress responses to non-optimal conditions. PMID:20943160
Nevarez, Laurent; Vasseur, Valťrie; Debaets, Stella; Barbier, Georges
The common premise for uncommon conclusions.
Recent controversy over philosophical advocacy of infanticide (or the comically-styled euphemism 'postnatal abortion') reveals a surprisingly common premise uniting many of the opponents and supporters of the practice. This is the belief that the moral status of the early fetus or embryo with respect to a right to life is identical to that of a newly born or even very young baby. From this premise, infanticidists and strong anti-abortionists draw opposite conclusions, the former that the healthy newly born have no inherent right to life and the latter that minute embryos and the very early fetus have the same right to life as young babies. (Indeed strong anti-abortionists tend to regard this right to life as identical to that possessed by adult humans.) This paper argues that these opposed conclusions are both deeply implausible and that the implausibility resides in the common premise. The argument requires some attention to the structure of the philosophical case underpinning the supposed vice of speciesism that has been given intellectual currency by many philosophers, most notably Peter Singer, and also to the reasoning behind the strong anti-abortionist adoption of the common premise. PMID:23637428
Coady, C A J
NWCC Transmission Case Study Conclusions Summary
OAK-B135 The NWCC Transmission Case Studies Conclusions Summary In the spring of 1999, the Utility Wind Interest Group (UWIG), with the cooperation of the National Wind Coordinating Committee (NWCC), conducted a forum on transmission issues associated with the production of energy from wind. As a result of this forum, a number of issues were identified which, if successfully resolved, could help reduce barriers to the future expansion of wind power. The NWCC, being a multi-stakeholder group, was in an ideal position to conduct follow-up activities among a cross-section of the interested parties. The follow-up activities took the form of three case studies in the areas of interest identified by forum participants: (1) Transmission policy and pricing; (2) ''Virtual wheeling'' arrangements; and, (3) Transmission system improvements. The case studies provide an interesting snapshot in time dealing with a range of issues associated with scheduled or planned regulatory and restructuring proceedings related to energy transmission. The NWCC Transmission Subcommittee and the UWIG reviewed early drafts of the case studies in November 1999. The case studies were conducted through a questionnaire and interview process with interested parties. In writing each case study, NWCC staff attempted to identify all stakeholder groups with an interest in each topic and solicit their input. While all parties do not agree on every issue presented, a serious effort has been made to present all views in an unbiased fashion. At the end of each case study, relevant conclusions are drawn and recommendations for next steps are provided where appropriate.
Steve Wiese, Terry Allison
Biofilm Formation by Endospore-forming Bacilli on Plastic Surface under Some Food-related and Environmental Stress Conditions
The effect of some food-related and environmental stress conditions (glucose or NaCl, nutrient starvation, heating, UV, agitation and temperature) on the ability of biofilm formation on polystyrene surface by vegetative cells of four Bacillus species was studied. The final concentration of glucose or NaCl in TSB was adjusted within the range relevant for the food industry (1 to 7%). The
Hesham M. Elhariry
Synthesis of Ammonia Using CH 4 \\/N 2 Plasmas Based on Micro-Gap Discharge under Environmentally Friendly Condition
The synthesis of ammonia has been studied in methane-nitrogen plasmas using a micro-gap discharge under an environmentally\\u000a friendly condition. The effects of some parameters such as the specific input energy, the discharge gap, the volume ratio\\u000a of CH4\\/N2, the residence time, and the gas temperature on the yield of NH3 and conversion rate of CH4 are discussed in the paper.
Mindong Bai; Zhitao Zhang; Mindi Bai; Xiyao Bai; Honghui Gao
The KwaZulu-Natal sardine run: shoal distribution in relation to nearshore environmental conditions, 1997Ė2007
The nearshore presence of sardine Sardinops sagax on the KwaZulu-Natal (KZN) coast was investi-gated using sightings data collected by the KZN Sharks Board from 1997 to 2007. The spatio-temporal distribution of sardine was described in relation to that of their predators and to environmental conditions, and subjected to generalised linear model (GLM) and generalised additive model (GAM) analyses. Variables describing
S H OíDonoghue; L Drapeau; S FJ Dudley; V M Peddemors
Interactive regulatory pathways control virulence determinant production and stability in response to environmental conditions in Staphylococcus aureus
The accessory gene regulator (agr) and staphylococcal accessory regulator (sar) loci are important regulators of toxin production in Staphylococcus aureus. In this study we examined how environmental conditions Ė degree of aeration and salt concentration Ė affect the transcription\\u000a and translation of mRNAs for ?- haemolysin (Hla) and serine protease (Ssp) via these pathways and influence the stability\\u000a of these
J. A. Lindsay; S. J. Foster
Comparative study on the behavior of woven-ply reinforced thermoplastic or thermosetting laminates under severe environmental conditions
This work aims at determining whether thermoplastic-based composites can be used in secondary aircraft structures to replace thermosetting-based composites or not. In order to answer this question, the mechanical behaviors of carbon fiber fabric reinforced thermoplastic (PPS or PEEK) and thermosetting (epoxy) laminates subjected to different stress states under severe environmental conditions (120įC after hygrothermal aging) have been compared. In
B. Vieille; J. Aucher; L. Taleb
Autofluorescence of atmospheric bioaerosols - Biological standard particles and the influence of environmental conditions
NASA Astrophysics Data System (ADS)
Primary biological aerosol particles (PBAP) such as pollen, fungal spores, bacteria, biogenic polymers and debris from larger organisms are known to influence atmospheric chemistry and physics, the biosphere and public health. PBAP can account for up to ~30% of fine and up to ~70% of coarse particulate matter in urban, rural and pristine environment and are released with estimated emission rates of up to ~1000 Tg/a [1]. Continuous measurements of the abundance, variability and diversity of PBAP have been difficult until recently, however. The application of on-line instruments able to detect autofluorescence from biological particles in real-time has been a promising development for the measurement of PBAP concentrations and fluxes in different environments [2,3]. The detected fluorescent biological aerosol particles (FBAP) can be regarded as a subset of PBAP, although the exact relationship between PBAP and FBAP is still being investigated. Autofluorescence of FBAP is usually a superposition of fluorescence from a mixture of individual fluorescent molecules (fluorophores). Numerous biogenic fluorophores such as amino acids (e.g., tryptophan, tyrosine), coenzymes (e.g., NAD(P)H, riboflavin) and biopolymers (e.g., cellulose) emit fluorescent light due to heterocyclic aromatic rings or conjugated double bonds within their molecular structures. The tryptophan emission peak is a common feature of most bioparticles because the amino acid is a constituent of many proteins and peptides. The influence of the coenzymes NAD(P)H and riboflavin on the autofluorescence of bacteria can be regarded as an indicator for bacterial metabolism and has been utilized to discriminate between viable and non-viable organisms [4]. However, very little information is available about other essential biofluorophores in fungal spores and pollen. In order to better understand the autofluorescence behavior of FBAP, we have used fluorescence spectroscopy and fluorescence microscopy to analyze standard bioparticles (pollen, fungal spores, and bacteria) as well as atmospherically relevant chemical substances. We addressed the sensitivity and selectivity of autofluorescence based online techniques. Moreover, we investigated the influence of environmental conditions, such as relative humidity and oxidizing agents in the atmosphere, on the autofluorescence signature of standard bioparticles. Our results will support the molecular understanding and quantitative interpretation of data obtained by real-time FBAP instrumentation [5,6]. [1] Elbert, W., Taylor, P. E., Andreae, M. O., & PŲschl, U. (2007). Atmos. Chem. Phys., 7, 4569-4588. [2] Huffman, J. A., Treutlein, B., & PŲschl, U. (2010). Atmos. Chem. Phys., 10, 3215-3233. [3] PŲschl, U., et al. (2010). Science, 329, 1513-1516. [4] Lakowicz, J., Principles of fluorescence spectroscopy, Plenum publishers, New York, 1999. [5] PŲhlker, C., Huffman, J. A., & PŲschl, U., (2012). Atmos. Meas. Tech., 5, 37-71. [6] PŲhlker, C., Huffman, J. A., FŲrster J.-D., & PŲschl, U., (2012) in preparation.
PŲhlker, Christopher; Huffman, J. Alex; FŲrster, Jan-David; PŲschl, Ulrich
Ecological Condition of the Estuaries of Oregon and Washington: Environmental Monitoring and Assessment Program (EMAP) Report.
National Technical Information Service (NTIS)
The overall quality of estuaries in Oregon and Washington is described in this report using data collected as part of the Western Environmental Monitoring and Assessment Program (EMAP). In EPA Region 10, Western EMAP is a cooperative effort between the En...
G. Hayslip, H. Lee, L. Edmond, V. Partridge, W. Nelson
Environmental Conditions at Tromsoeflaket. Results of Measurements from 1976 to 1981.
National Technical Information Service (NTIS)
Since September 1976 the observation ship AMI has occupied the position 71 degrees 30 minutes N, 19 degrees 00 minutes E at Tromsoeflaket, off the coast of Northern Norway, in order to perform an environmental data measurement program. The background for ...
S. Tryggestad K. A. Orvik S. Haver L. I. Eide S. Sundby
Effectiveness of current remote sensing systems for monitoring environmental conditions at US Army installations
The Pacific Northwest National Laboratory Remote Sensing Group and the U.S. Army at Fort Lewis Washington have been developing and applying customized remote sensing and GIS techniques to support environmental management activities at the Fort Lewis and Yakima Training Center (YTC) installations. This effort has evaluated imagery from all currently available satellite systems including LANDSAT, SPOT and RADARSAT as well
G. M. Petrie; G. E. Wukelic; R. W. Hanna
40 CFR 86.161-00 - Air conditioning environmental test facility ambient requirements.
Code of Federal Regulations, 2011 CFR
...Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty Vehicles...operating on a specific driving cycle. The environmental facility...and humidity, minimum test cell size, solar heating, and vehicle...controlled, within the test cell, during all phases of the...
40 CFR 86.161-00 - Air conditioning environmental test facility ambient requirements.
Code of Federal Regulations, 2012 CFR
...Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty Vehicles...operating on a specific driving cycle. The environmental facility...and humidity, minimum test cell size, solar heating, and vehicle...controlled, within the test cell, during all phases of the...
Hypoxia tolerance of common sole juveniles depends on dietary regime and temperature at the larval stage: evidence for environmental conditioning.
An individual's environmental history may have delayed effects on its physiology and life history at later stages in life because of irreversible plastic responses of early ontogenesis to environmental conditions. We chose a marine fish, the common sole, as a model species to study these effects, because it inhabits shallow marine areas highly exposed to environmental changes. We tested whether temperature and trophic conditions experienced during the larval stage had delayed effects on life-history traits and resistance to hypoxia at the juvenile stage. We thus examined the combined effect of global warming and hypoxia in coastal waters, which are potential stressors to many estuarine and coastal marine fishes. Elevated temperature and better trophic conditions had a positive effect on larval growth and developmental rates; warmer larval temperature had a delayed positive effect on body mass and resistance to hypoxia at the juvenile stage. The latter suggests a lower oxygen demand of individuals that had experienced elevated temperatures during larval stages. We hypothesize that an irreversible plastic response to temperature occurred during early ontogeny that allowed adaptive regulation of metabolic rates and/or oxygen demand with long-lasting effects. These results could deeply affect predictions about impacts of global warming and eutrophication on marine organisms. PMID:23486433
Zambonino-Infante, Josť L; Claireaux, Guy; Ernande, Bruno; Jolivet, Aurťlie; Quazuguel, Patrick; SťvŤre, Armelle; Huelvan, Christine; Mazurais, David
Hypoxia tolerance of common sole juveniles depends on dietary regime and temperature at the larval stage: evidence for environmental conditioning
An individual's environmental history may have delayed effects on its physiology and life history at later stages in life because of irreversible plastic responses of early ontogenesis to environmental conditions. We chose a marine fish, the common sole, as a model species to study these effects, because it inhabits shallow marine areas highly exposed to environmental changes. We tested whether temperature and trophic conditions experienced during the larval stage had delayed effects on life-history traits and resistance to hypoxia at the juvenile stage. We thus examined the combined effect of global warming and hypoxia in coastal waters, which are potential stressors to many estuarine and coastal marine fishes. Elevated temperature and better trophic conditions had a positive effect on larval growth and developmental rates; warmer larval temperature had a delayed positive effect on body mass and resistance to hypoxia at the juvenile stage. The latter suggests a lower oxygen demand of individuals that had experienced elevated temperatures during larval stages. We hypothesize that an irreversible plastic response to temperature occurred during early ontogeny that allowed adaptive regulation of metabolic rates and/or oxygen demand with long-lasting effects. These results could deeply affect predictions about impacts of global warming and eutrophication on marine organisms.
Zambonino-Infante, Jose L.; Claireaux, Guy; Ernande, Bruno; Jolivet, Aurelie; Quazuguel, Patrick; Severe, Armelle; Huelvan, Christine; Mazurais, David
Modeling the effects of environmental conditions on HT2 and T2 toxin accumulation in field oat grains.
Fusarium head blight (FHB) of wheat and barley has been extensively researched worldwide; in contrast, there is limited information on the effects of environmental conditions on Fusarium toxin accumulation in oat grains. More than 300 samples of oat grain from various regions of the United Kingdom from 2006 to 2008 were analyzed for mycotoxin contamination due to infection by Fusarium spp. HT2 and T2 toxins were the two most commonly detected, and their concentrations in individual samples were highly correlated. Hourly weather data were obtained from meteorological recording stations near most of the sampling sites. Statistical modeling was applied to both the original toxin (HT2 plus T2) data and the toxin data adjusted for oat cultivars and number of cereal crops in the previous four seasons. Accumulation of HT2 and T2 toxin was positively correlated with warm and wet conditions during early May and dry conditions thereafter. Using a collection of 51 environmental variables summarized over three lengths (10, 15, and 20 days) of time periods encompassing early May, late May, and early July, all-subsets regression showed that many models, consisting of three to six predictor variables, could be identified with similar explanatory strength for the effect of environmental conditions on toxin accumulation. Most important predictor variables were related to wet conditions during the early-May period, which was before anthesis. These results suggest that the predominant period for Fusarium langsethiae infection of oat is likely to be before rather than during anthesis, as for other head blight pathogens. These empirical models may be further improved by using quantified pathogen biomass within the grains and weather predictor variables summarized in relation to plant growth stages (instead of calendar times). PMID:23883158
Xu, Xiangming; Madden, Laurence V; Edwards, Simon G
Conclusiveness of natural languages and recognition of images
The conclusiveness is investigated using recognition processes and one-one correspondence between expressions of a natural language and graphs representing events. The graphs, as conceived in psycholinguistics, are obtained as a result of perception processes. It is possible to generate and process the graphs automatically, using computers and then to convert the resulting graphs into expressions of a natural language. Correctness and conclusiveness of the graphs and sentences are investigated using the fundamental condition for events representation processes. Some consequences of the conclusiveness are discussed, e.g. undecidability of arithmetic, human brain assymetry, correctness of statistical calculations and operations research. It is suggested that the group theory should be imposed on mathematical models of any real system. Proof of the fundamental condition is also presented. 14 references.
Wojcik, Z.M.
Physiological responses of Spartina alterniflora to varying environmental conditions in Virginia marshes
Physiological measurements were used to investigate the dependence of photosynthesis on light, temperature, and intercellular\\u000a carbon dioxide (CO2) levels in the C4 marsh grass Spartina alterniflora. Functional relationships between these environmental variables and S. alterniflora physiological responses were then used to improve C4-leaf photosynthesis models. Field studies were conducted in monocultures of S. alterniflora in Virginia, USA. On average, S.
James C. Kathilankal; Thomas J. Mozdzer; Josť D. Fuentes; Karen J. McGlathery; Paolo DíOdorico; Jay C. Zieman
Evaluation of the Environmental Impact of different Lubrorefrigeration Conditions in Milling of ?-TiAl Alloy
\\u000a Conventional manufacturing techniques have not been subject to much scrutiny by industrial ecologist to date. The implementation\\u000a of environment-friendly methodologies in metal cutting is, consequently, of considerable direct economic, social and technological\\u000a importance. This paper aims to analyze the milling operation of a non conventional material such as ?-TiAl alloy from an environmental\\u000a point of view, taking into account the
Giovanna Rotella; Paolo Claudio Priarone; Stefania Rizzuti; Luca Settineri
The influence of environmental conditions on polysaccharide formation by Ganoderma lucidum in submerged cultures
The effects of environmental parameters on polysaccharide formation by Ganoderma lucidum were investigated in submerged cultures. The optimal temperature and pH was 30Ė35įC and 4Ė4∑5, respectively, in a glucose-ammonium chloride medium and polysaccharide concentration reached 1∑6 mg\\/ml. Agitation and aeration influenced the formation and secretion of polysaccharide. The optimal rotating speed was 150 rpm in 7-day flask cultures, while the
Fan-Chiang Yang; Chun-Bun Liau
How to improve housing conditions of laboratory animals: the possibilities of environmental refinement.
Housing systems for captive animals have often been designed on the basis of economic and ergonomic considerations, such as equipment, costs, space, workload, ability to observe the animals and to maintain a certain degree of hygiene, with little or no consideration for animal welfare. Environmental refinement can be defined as any modification in the environment of captive animals that seeks to enhance the physical and psychological well-being of the animals by providing stimuli which meet the animals' species-specific needs. This article provides an overview of environmental factors that influence the well-being of captive animals with specific reference to the needs of the most common laboratory species. It is important to evaluate environmental refinement in terms of the benefit to the animal, by assessing the use of and preference for certain enrichment, the effect on behaviour, and the performance of species-typical behaviour on physiological parameters. It is also necessary to evaluate the impact of refinement on scientific outcome, including whether and how statistical power is affected. Communication and team work between animal welfare scientists, animal research scientists, institutional animal welfare officers, veterinarians and animal ethics committees, animal facility management and personnel, are essential for success. PMID:23127868
Baumans, V; Van Loo, P L P
Global Advisory Group: conclusions and recommendations.
The conclusions and recommendations formulated for the global program by the 8th meeting of the Expanded Program on Immunization (EPI) Global Advisory Group, which took place during November 1985, are summarized. The Global Advisory Group recommends that, in furtherance of the Five-Point Action Program endorsed by the World Health Assembly in 1983, 3 general and 4 specific actions be taken by national immunization programs with the support of the World Health Organization (WHO) to accelerate EPI progress. These recommendations reflect optimism that the 1990 goal of reducing morbidity and mortality by providing immunization for all children of the world can be realized but also acknowledge that many fundamental problems of national program management remain to be resolved. The general actions are: to promote the achievement of the 1990 immunization goal at national and international levels through collaboration among ministries, organizations, and individuals in both the public and private sectors; to adopt a mix of complementary strategies for program acceleration; and to ensure that rapid increases in coverage can be sustained through mechanisms which strengthen th delivery of other primary health care interventions. The specific actions are as follows: to provide immunization at every contact point; to reduce dropout rates between 1st and last immunizations; to improve immunization services to the disadvantaged in urban areas; and to increase priority for the control of measles, poliomyelitis, and neonatal tetanus. The WHO and the UN International Children's Emergency Fund (UNICEF) have collaborated in support of the EPI since the early days of the program. The acceleration of national efforts heightens the importance of this collaboration, particularly at the national level. It may be further facilitated by the provision of policy guidance from global and regional levels, by WHO and UNICEF collaborative agreements at the regional level, and by country agreements jointly signed by governments, WHO, UNICEF, and other major partners in the immunization effort. Involvement of nongovernmental organizations is of special importance in light of the current accelrated immunization activities. The role of NGSs needs to be clearly defined within each country program. National action plans should be drawn up with agreement between all parties concerned as to their individual responsibilities within the program. Appropriate recognition of the involvement of NGOs is essential to their fund raising and social mobilization efforts. Immunization training in schools for health personnel needs to be improved. Examples of operational problems requiring research are outlined. Research and development effots which facilitate sterile injection practice are an urgent need and deserve strong support. PMID:12314333
Performances of the Radiello ģ diffusive sampler for BTEX measurements: Influence of environmental conditions and determination of modelled sampling rates
NASA Astrophysics Data System (ADS)
Radiello ģ diffusive samplers filled with a thermally desorbable adsorbent (graphitised carbon Carbograph 4) have been evaluated for the monitoring of BTEX according to the European standard EN 13528-2. Blank values and analytical recovery rates were in agreement with the requirements of this protocol. The sampling rates have been estimated under various controlled atmospheres in order to evaluate the effects of some environmental factors on the performances of the Radiello ģ sampler: concentration levels, temperature, exposure time, humidity and wind velocity. The effects of back diffusion and a mixture of 37 VOC have been determined. According to the whole of these results, modelled sampling rates have been set up. These experiments in exposure chamber showed that, for a medium level of concentration in air (5 ?g m -3 for benzene), the expanded uncertainties were between 20% for benzene and 27% for m/ p-xylene under environmental indoor conditions and between 19% for benzene and 31% for m/ p-xylene under environmental outdoor conditions. The result for benzene is conform to the requirements of the future European Directive for benzene which define the maximum of uncertainty to 25% for annual concentrations near 5 ?g m -3.
Pennequin-Cardinal, Anne; Plaisance, Hervť; Locoge, Nadine; Ramalho, Olivier; Kirchner, Sťverine; Galloo, Jean-Claude
Changes in body composition during breeding: Reproductive strategies of three species of seabirds under poor environmental conditions.
Seabirds differ dramatically in life history traits and breeding strategies. For example, gulls have short incubation shifts (several hours) and high metabolic rates, auks have medium-length incubation shifts (12-24h) and high metabolic rates, and petrels have long incubation shifts (days) and low metabolic rates. How these different strategies affect the dynamics of body components is poorly known. We compared body, organ and lipid mass changes among three different seabirds (gull: black-legged kittiwake Rissa tridactyla; auk: thick-billed murre Uria lomvia; petrel: northern fulmar Fulmarus glacialis) at Prince Leopold Island, Nunavut, Canada during 2002 (a year with low reproductive success and poor chick growth across all three species). This study is among the first to compare mass and lipid dynamics among different species foraging in the same food web and at similar trophic levels during the same breeding season (same environmental conditions). In fulmars and murres, most of decreases in body mass reflected decreases in lipid mass while in kittiwakes the increase in body mass reflected an increase in lean mass, especially the muscle. The species with the longest fasting endurance (incubation shift length) had the highest percent body lipids during incubation (fulmars: 13.3%, murres: 7.3%, kittiwakes: 6.9%), the highest variability in body lipids, tended to regulate body mass primarily through lipid stores and tended to regulate exercise and digestive organs separately. In contrast, in the species with the highest metabolic rate, all organ systems were adjusted similarly and in relation to body mass, and in a similar manner between incubation (stress due to heavy ice conditions) and chick-rearing (lower stress due to ice-free conditions). In high metabolic rate species, we suggest that organ size varies in response to environmental stress. We conclude that the organ dynamics of seabirds are set by a combination of key life history traits (like incubation shift and metabolic rate) and environmental conditions. PMID:20888927
Jacobs, Shoshanah R; Edwards, Darryl B; Ringrose, Julian; Elliott, Kyle H; Weber, Jean-Michel; Gaston, Anthony J
Assessing the aggregation behaviour of iron oxide nanoparticles under relevant environmental conditions using a multi-method approach.
Iron nanoparticles are becoming increasingly popular for the treatment of contaminated soil and groundwater; however, their mobility and reactivity in subsurface environments are significantly affected by their tendency to aggregate. Assessing their stability under environmental conditions is crucial for determining their environmental fate. A multi-method approach (including different size-measurement techniques and the DLVO theory) was used to thoroughly characterise the behaviour of iron oxide nanoparticles (Fe2O3NPs) under environmentally relevant conditions. Although recent studies have demonstrated the importance of using a multi-method approach when characterising nanoparticles, the majority of current studies continue to use a single-method approach. Under some soil conditions (i.e. pH 7, 10 mM NaCl and 2 mM CaCl2) and increasing particle concentration, Fe2O3NPs underwent extensive aggregation to form large aggregates (>1 ?m). Coating the nanoparticles with dissolved organic matter (DOM) was investigated as an alternative "green" solution to overcoming the aggregation issue instead of using the more commonly proposed polyelectrolytes. At high concentrations, DOM effectively covered the surface of the Fe2O3NPs, thereby conferring negative surface charge on the particles across a wide range of pH values. This provided electrostatic stabilisation and considerably reduced the particle aggregation effect. DOM-coated Fe2O3NPs also proved to be more stable under high ionic strength conditions. The presence of CaCl2, however, even at low concentrations, induced the aggregation of DOM-coated Fe2O3NPs, mainly via charge neutralisation and bridging. This has significant implications in regards to the reactivity and fate of these materials in the environment. PMID:23764608
Chekli, Laura; Phuntsho, Sherub; Roy, Maitreyee; Lombi, Enzo; Donner, Erica; Shon, Ho Kyong
At their core, ecological risk assessments aim to evaluate the biological integrity and long-term sustainability of natural ecosystems. These are difficult objectives that will ultimately require development of novel indicators of ecological condition that are more accurate and ...
Assessment of Fungal Growth on Ceiling Tiles under Environmentally Characterized Conditions.
National Technical Information Service (NTIS)
The paper discusses investigation of the impact of the building environment on the ability of building materials to support microbial growth, using static chambers with defined relative humidity, temperature, and light conditions. The ability of fungi to ...
K. Foarde P. Dulaney E. Cole D. VanOsdell D. Ensor
Environmental Conditions in northern Gulf of Mexico Estuaries: before and after the BP Oil Spill
This presentation provides a summary of ecological condition and sediment chemistry data for northern Gulf of Mexico estuaries that were exposed to oil and oil-related contaminants from the BP Oil Spill. ...
Transcriptional response of Desulfovibrio vulgaris Hildenborough to oxidative stress mimicking environmental conditions
Sulfate-reducing bacteria (SRB) are anaerobes readily found in oxicĖanoxic interfaces. Multiple defense pathways against oxidative\\u000a conditions were identified in these organisms and proposed to be differentially expressed under different concentrations of\\u000a oxygen, contributing to their ability to survive oxic conditions. In this study, Desulfovibrio vulgaris Hildenborough cells were exposed to the highest concentration of oxygen that SRB are likely to
PatrŪcia M. Pereira; Qiang He; Antůnio V. Xavier; Jizhong Zhou; InÍs A. C. Pereira; Ricardo O. Louro
Results on the survival of cryptobiotic cyanobacteria samples after exposure to Mars-like environmental conditions
NASA Astrophysics Data System (ADS)
Tests on cyanobacteria communities embedded in cryptobiotic crusts collected in hot and cold deserts on Earth were performed under Mars-like conditions. The simulations were realized as a survey, to find the best samples for future research. During the tests organisms have to resist Mars-like conditions such as atmospheric composition, pressure, variable humidity (saturated and dry conditions) and partly strong UV irradiation. Organisms were tested within their original habitat inside the crust. Nearly half of the cryptobiotic samples from various sites showed survival of a substantial part of their coexisting organisms. The survival in general depended more on the nature of the original habitat and type of the sample than on the different conditions they were exposed to. The best survival was observed in samples from United Arab Emirates (Jebel Ali, 25 km SW of Dubai town) and from Western Australia (near the South edge of Lake Barley), by taxa: Tolypothrix byssoidea, Gloeocapsopsis pleurocapsoides, Nostoc microscopicum, Leptolyngbya or Symploca sp. At both places in salty desert areas members of the Chenopodiaceae family dominated among the higher plants and in the cryptobiotic crust cyanobacterial taxa Tolypothrix was dominant. These organisms were all living in salty locations with dry conditions most of the year. Among them Tolypothrix, Gloeocapsopsis and Symploca sp. were tested in Mars simulation chambers for the first time. The results suggest that extremophiles should be tested with taken into account the context of their original microenvironment, and also the importance to analyse communities of microbes beside single organisms.
de Vera, J.-P.; Dulai, S.; Kereszturi, A.; Koncz, L.; Lorek, A.; Mohlmann, D.; Marschall, M.; Pocs, T.
Environmental conditions and body temperatures of elderly women living alone or in local authority home.
The environmental and body temperatures of two groups of elderly women have been measured. One group was living in a local authority home (L.A.H.) and the others in their own homes in North London. The L.A.H. provided a constant environmental temperature which was at all times higher than that of the private houses. In the latter group the ambient temperature was higher in bed-sitting rooms than in houses with separate living rooms and bedrooms.Body temperatures in summer were similar throughout both groups. In winter the skin and mouth temperatures of the subjects living independently were lower than those in the L.A.H.Four subjects who had low mouth temperatures measured during two consecutive winters did not prove to have lowered deep body temperatures. The diet of these four subjects was similar in respect of all nutrients to that found in other groups of subjects of the same age, and in relation to published dietary standards was adequate in all respects. PMID:5134562
Salvosa, C B; Payne, P R; Wheeler, E F
Robust Vehicle Detection under Various Environmental Conditions Using an Infrared Thermal Camera and Its Application to Road Traffic Flow Monitoring
We have already proposed a method for detecting vehicle positions and their movements (henceforth referred to as ďour previous methodĒ) using thermal images taken with an infrared thermal camera. Our experiments have shown that our previous method detects vehicles robustly under four different environmental conditions which involve poor visibility conditions in snow and thick fog. Our previous method uses the windshield and its surroundings as the target of the Viola-Jones detector. Some experiments in winter show that the vehicle detection accuracy decreases because the temperatures of many windshields approximate those of the exterior of the windshields. In this paper, we propose a new vehicle detection method (henceforth referred to as ďour new methodĒ). Our new method detects vehicles based on tires' thermal energy reflection. We have done experiments using three series of thermal images for which the vehicle detection accuracies of our previous method are low. Our new method detects 1,417 vehicles (92.8%) out of 1,527 vehicles, and the number of false detection is 52 in total. Therefore, by combining our two methods, high vehicle detection accuracies are maintained under various environmental conditions. Finally, we apply the traffic information obtained by our two methods to traffic flow automatic monitoring, and show the effectiveness of our proposal.
Iwasaki, Yoichiro; Misumi, Masato; Nakamiya, Toshiyuki
Robust vehicle detection under various environmental conditions using an infrared thermal camera and its application to road traffic flow monitoring.
We have already proposed a method for detecting vehicle positions and their movements (henceforth referred to as "our previous method") using thermal images taken with an infrared thermal camera. Our experiments have shown that our previous method detects vehicles robustly under four different environmental conditions which involve poor visibility conditions in snow and thick fog. Our previous method uses the windshield and its surroundings as the target of the Viola-Jones detector. Some experiments in winter show that the vehicle detection accuracy decreases because the temperatures of many windshields approximate those of the exterior of the windshields. In this paper, we propose a new vehicle detection method (henceforth referred to as "our new method"). Our new method detects vehicles based on tires' thermal energy reflection. We have done experiments using three series of thermal images for which the vehicle detection accuracies of our previous method are low. Our new method detects 1,417 vehicles (92.8%) out of 1,527 vehicles, and the number of false detection is 52 in total. Therefore, by combining our two methods, high vehicle detection accuracies are maintained under various environmental conditions. Finally, we apply the traffic information obtained by our two methods to traffic flow automatic monitoring, and show the effectiveness of our proposal. PMID:23774988
Iwasaki, Yoichiro; Misumi, Masato; Nakamiya, Toshiyuki
Droplet-turbulence interactions in sprays exposed to supercritical environmental conditions
NASA Technical Reports Server (NTRS)
The goal of this research was to experimentally characterize the behavior of droplets in vaporizing sprays under conditions typical of those encountered in high pressure combustion systems such as liquid fueled rocket engines. Of particular interest are measurements of droplet drag and lift, droplet dispersion, droplet heating, and droplet vaporization under both subcritical and supercritical conditions. A summary of the major accomplishments achieved during the period from June 1990 through June 1993, a brief description and status report on five research areas, which were directly or indirectly supported by this grant, and a list of publications and personnel associated with this research is included.
Santavicca, Domenic A.
Measuring health outcomes of a multidisciplinary care approach in individuals with chronic environmental conditions using an abbreviated symptoms questionnaire
The Nova Scotia Environmental Health Centre is a treatment facility for individuals with chronic environmental conditions such as multiple chemical sensitivity, chronic fatigue syndrome, fibromyalgia, chronic respiratory conditions and in some cases chronic pain. The premise of care is to provide a patient-centred multidisciplinary care approach leading to self-management strategies. In order to measure the outcome of the treatment in these complex problems, with overlapping diagnoses, symptoms in many body systems and suspected environmental triggers, a detailed symptoms questionnaire was developed specifically for this patient population and validated. Results from a pilot study in which an abbreviated symptoms questionnaire based on the top reported symptoms captured in previous research was used to measure the efficacy of a multidisciplinary care approach in individuals with multiple chemical sensitivity are presented in this paper. The purpose of this study was to examine the extent, type and patterns of changes over time in the top reported symptoms with treatment measured using the abbreviated symptoms questionnaire. A total of 183 active and 109 discharged patients participated in the study where the health status was measured at different time periods of follow up since the commencement of treatment at the Centre. The findings from this study were successful in generating an initial picture of the nature and type of changes in these symptoms. For instance, symptoms such as difficulty concentrating, sinus conditions and tiredness showed early improvement, within the first 6 months of being in treatment, while others, such as fatigue, hoarseness or loss of voice, took longer while others showed inconsistent changes warranting further enquiry. A controlled longitudinal study is planned to confirm the findings of the pilot study.
Fox, Roy; Sampalli, Tara; Fox, Jonathan
Establishing Baseline environmental Conditions for the Proposed Yucca Mountain Repository, Nevada, U.S.A
Research is underway to develop baseline site conditions and design monitoring programs for assurance to offsite residents and for performance confirmation for the proposed Yucca Mountain (YM) high-level waste repository in Nevada. This includes evaluation of existing and potential impacts on the proposed ''land withdrawal'' for the repository. A significant portion of the proposed land withdrawal includes areas now managed
D. S. Shafer; K. F. Pohlmann; C. E. Russell; D. Hovey-Spencer; M. Ye
Degradation of High Voltage Polymeric Insulators in Arid Desert's Simulated Environmental Conditions
Problem statement: High Voltage (HV) polymeric insulators are replacin g ceramic insulator commonly used for HV outdoor networks due to their ease of handling, reliability and cost. However, their long term performance and reliabilit y are major concerns to power utilities. Approach: To investigate their performance in arid desert's conditions, two types of HV composite insulators were aged as per
Yasin Khan
The toxicity of pentachlorophenol (PCP) was determined in the laboratory for 11 aquatic species. Tests were conducted seasonally in ambient Mississippi River water and under controlled conditions in Lake Superior water. Fifty-one acute toxicity tests were conducted, with LC50 val...
Acquiring an attacking forehand drive: the effects of static and dynamic environmental conditions.
Two groups of 10 novice subjects each were trained to perform attacking forehand drives in table tennis and land the balls as fast and as accurately as possible onto a target on the opposite side of the net under two different training conditions. Under the static training condition, the balls were to be struck from a constant position, and under the dynamic training condition, balls approached the subjects in a normal way. Both groups were tested under dynamic conditions prior to and after four days of training, during which they received 1,600 practice trials. Both groups of subjects were shown to increase the number of balls that landed on the target, and learning was also evident from an increased consistency of the direction of travel of the bat at the moment of ball/bat contact. However, no increase in consistency was found for the location of the bat at the moment of ball/bat contact and for the movement times. Thus, learning can occur in the absence of externally generated time-to-contact information, but this is not due to the establishment of a consistent movement form. Learning appears to progress from control at the moment of ball/bat contact backward, toward the moment of initiation. PMID:1925055
Bootsma, R J; Houbiers, M H; Whiting, H T; van Wieringen, P C
Relationship between foliar chemical parameters measured in Melia Azedarach L. and environmental conditions in urban areas
A diagnostic study was done on Melia azedarach L. in relation to atmospheric pollutants in Cůrdoba city, Argentina. The study area receives regional pollutants, and it was categorized taking into account traffic level, industrial level, location of the sample point in relation to the corner, treeless condition, building type, topographic level and distance to the river. Water content and Specific
Mar??a L Pignata; Gustavo L GudiŮo; Martha S CaŮas; Liliana Orellana
Role of Environmental Conditions on the Interaction of L-Arginine with Oxide Mineral Surfaces
NASA Astrophysics Data System (ADS)
The current study is focused on surface interactions between L-arginine, the most basic protein amino acid, and rutile in NaCl media over a wide range of solution pH conditions, amino acid concentrations, and solution ionic strengths.
Klochko, K.; Jonsson, C. M.; Jonsson, C. L.; Lee, N.; Cleaves, H. J., II; Sverjensky, D. A.; Hazen, R. M.
The Relationship between Environmental Conditions and Transfer Rates of Selected Rural Community Colleges: A Pilot Study.
ERIC Educational Resources Information Center
Investigates the relationship between transfer rates and conditions that are beyond an institution's control. Finds that the percentage of students under age 25 and the percent of adults with a high school degree are positively associated with transfer, while expenditures per FTE, the percentage of males enrolled, and population density areÖ
Higgins, C. Steven; Katsinas, Stephen G.
Challenges for Physical Characterization of Silver Nanoparticles Under Pristine and Environmentally Relevant Conditions
The reported size distribution of silver nanoparticles (AgNPs) is strongly affected by the underlying measurement method, agglomeration state, and dispersion conditions. A selection of AgNP materials with vendor-reported diameters ranging from 1 nm to 100 nm, various size distrib...
The effect of early environmental manipulation on locomotor sensitivity and methamphetamine conditioned place preference reward.
Early life stress leads to several effects on neurological development, affecting health and well-being later in life. Instances of child abuse and neglect are associated with higher rates of depression, risk taking behavior, and an increased risk of drug abuse later in life. This study used repeated neonatal separation of rat pups as a model of early life stress. Rat pups were either handled and weighed as controls or separated for 180 min per day during postnatal days 2-8. In adulthood, male and female rats were tested for methamphetamine conditioned place preference reward and methamphetamine induced locomotor activity. Tissue samples were collected and mRNA was quantified for the norepinephrine transporter in the prefrontal cortex and the dopamine transporter in the nucleus accumbens. Results indicated rats given methamphetamine formed a conditioned place preference, but there was no effect of early separation or sex. Separated males showed heightened methamphetamine-induced locomotor activity, but there was no effect of early separation for females. Overall females were more active than males in response to both saline and methamphetamine. No differences in mRNA levels were observed across any conditions. These results suggest early neonatal separation affects methamphetamine-induced locomotor activity in a sex-dependent manner but has no effects on methamphetamine conditioned place preference. PMID:24713150
Hensleigh, E; Pritchard, L M
Okayama Downbursts on 27 June 1991: Downburst Identifications and Environmental Conditions
On the afternoon of 27 June 1991, the Okayama area in the western part of Japan was hit by strong gusty winds and a heavy precipitation of rain and hail associated with severe thunderstorms. The synoptic condition was that the area was located to the south of the Baiu-front with the northern edge of the Pacific Subtropical Anticyclone (PSA) prevailing.
Hisao Ohno; Osamu Suzuki; Hiroshi Nirasawa; Masanori Yoshizaki; N. Hasegawa; Yoshio. Tanaka; Y MURAMATSU; Yoshi Ogura
The effect of surface condition and sulfur on the environmental resistance of airfoils
The environmental protection of aircraft engine high-pressure turbine blades is dependent upon the formation of a thin, slow-growing, external alumina scale. The adherence of alumina (Al{sub 2}O{sub 3}) scales to superalloys or coatings has been shown to be improved by adding an oxygen-active element (Y) or by desulfurization. Studies will be presented that show that cast surfaces are contaminated with sulfur and are more susceptible to high-velocity oxidation than machined surfaces regardless of an oxygen-active-element addition. In addition, the positive effect of oxygen-active elements and desulfurization on the performance of a single-crystal and directionally solidified Ni-base super-alloy in a 1149{degrees}C cyclic oxidation test and a 927{degrees}C/5 ppm sea-salt Type-I hot-corrosion test will be discussed.
Schaeffer, J.C.; Murphy, W.H. [GE Aircraft Engines, Cincinatti, OH (United States); Smialek, J.L. [NASA Lewis Research Center, Cleveland, OH (United States)
Linking shoreline displacement to environmental conditions in the Wax Lake Delta, USA
NASA Astrophysics Data System (ADS)
The dynamics of river deltas are not well-understood in part because of scarcity of historical data that document the growth or retreat of their channel networks, islands and shorelines. In particular, the mapping of deltaic shorelines is not trivial, however recent developments allow for their extraction from satellite and aerial imagery. Here, we present an analysis of environmental data and Landsat imagery of the Wax Lake Delta, a naturally-developing river delta in the shallow Atchafalaya Basin, Gulf of Mexico, USA. The image-based shoreline corresponds to the hydrodynamic shoreline, that is, the boundary of the subaerial and subaqueous portions of the delta, however, can be related to a morphodynamically-relevant shoreline by application of our method [Geleynse et al., 2012] to bathymetric-topographic data. Moreover, the effect of tides, river floods, wind, and vegetation cover on the extracted shorelines of the Wax Lake Delta can be identified.
Geleynse, N.; Hiatt, M. R.; Sangireddy, H.; Passalacqua, P.
Assessing the environmental impact of biobleaching: effects of the operational conditions.
The environmental impact of enzyme bleaching stages applied to oxygen-delignified eucalypt kraft pulp was assessed via the chemical oxygen demand (COD), color, absorbance spectrum, residual enzyme activity and Microtox toxicity of the effluents from a laccase-HBT (1-hydoxybenzotriazole) treatment. The influence of the laccase and HBT doses, and reaction time, on these effluent properties was also examined. The laccase dose was found to be the individual variable most strongly affecting COD, whereas the oxidized form of HBT was the main source of increased color and toxicity in the effluents. Moreover, it inactivated the enzyme. Oxidation of the mediator was very fast and essentially dependent on the laccase dose. Using the laccase-mediator treatment after a xylanase stage improved pulp properties without affecting effluent properties. This result holds great promise with a view to the industrial implementation of biobleaching sequences involving the two enzymes in the future. PMID:22079687
Valls, Cristina; Quintana, Elisabet; Roncero, M Blanca
Total environmental warming impact (TEWI) calculations for alternative automative air-conditioning systems
The Montreal Protocol phase-out of chlorofluorocarbons (CFCs) has required manufacturers to develop refrigeration and air-conditioning systems that use refrigerants that can not damage stratospheric ozone. Most refrigeration industries have adapted their designs to use hydrochlorofluorocarbon (HCFC) or hydrofluorocarbon (HFC) refrigerants; new automobile air- conditioning systems use HFC-134a. These industries are now being affected by scientific investigations of greenhouse warming and questions about the effects of refrigerants on global warming. Automobile air-conditioning has three separate impacts on global warming; (1) the effects of refrigerant inadvertently released to the atmosphere from accidents, servicing, and leakage; (2) the efficiency of the cooling equipment (due to the emission of C0{sub 2} from burning fuel to power the system); and (3) the emission of C0{sub 2} from burning fuel to transport the system. The Total Equivalent Warming Impact (TEWI) is an index that should be used to compare the global warming effects of alternative air-conditioning systems because it includes these contributions from the refrigerant, cooling efficiency, and weight. This paper compares the TEWI of current air-conditioning systems using HFC-134a with that of transcritical vapor compression system using carbon dioxide and systems using flammable refrigerants with secondary heat transfer loops. Results are found to depend on both climate and projected efficiency of C0{sub 2}systems. Performance data on manufacturing prototype systems are needed to verify the potential reductions in TEWI. Extensive field testing is also required to determine the performance, reliability, and ``serviceability`` of each alternative to HFC-134a to establish whether the potential reduction of TEWI can be achieved in a viable consumer product.
Sand, J.R.; Fischer, S.K.
[Fundamentals of socio-hygienic monitoring of environmental conditions for students of higher education schools].
Socioeconomic transformations and the poor environment of an industrial megalopolis negatively affected quality of life and morbidity rates in students (n = 2160). Academic intensity contributed to an increase in overall morbidity and morbidity from nervous system involvement. The regional sociohygienic monitoring of high-school training conditions within the framework of the surveillance system substantiates programs to prevent worse health and life quality in high school students. PMID:22712322
Blinova, E G; Kuchma, V R
Durability study of neat\\/nanophased GFRP composites subjected to different environmental conditioning
Experimental investigations on the durability of E-glass\\/nanoclayĖepoxy composites are reported. SC-15 epoxy system was modified using 1Ė2wt.% of nanoclay. Extent of clay platelet exfoliation in epoxy was evaluated using X-ray diffraction (XRD). Glass fiber reinforced plastic (GFRP) composite panels were fabricated using modified epoxy and exposed to four different conditions, i.e. hot (elevated temperature-dry, wet: 60 and 80įC) and cold
S. Zainuddin; M. V. Hosur; Y. Zhou; Ashok Kumar; S. Jeelani
Analysis of the Salmonella typhimurium Proteome through Environmental Response toward Infectious Conditions
Salmonella enterica serovar Typhimurium (aka, S. typhimurium) is a facultative intracellular pathogen that causes ~40,000 reported cases of acute gastroenteritis and diarrhea a year in the United States. To develop a deeper understanding of the infectious state of S. typhimurium, liquid chromatography-mass spectrometry-based 'bottom-up'Ě proteomics was used to globally analyze the proteins present under specific growth conditions. Salmonella typhimurium LT2
Joshua N. Adkins; Heather M. Mottaz; Angela D. Norbeck; Jean K. Gustin; Joanne Rue; Therese R. W. Clauss; Samuel O. Purvine; Karin D. Rodland; Fred Heffron; Richard D. Smith
Microbial Diversity During Cellulose Decomposition in Different Forest Stands: I. Microbial Communities and Environmental Conditions
We studied the effect of forest tree species on a community of decomposers that colonize cellulose strips. Both fungal and\\u000a bacterial communities were targeted in a native forest dominated by beech and oak and 30-year-old beech and spruce plantations,\\u000a growing in similar ecological conditions in the Breuil-Chenue experimental forest site in Morvan (France). Microbial ingrowths\\u000a from the 3rd to 10th
Ariana KubartovŠ; JudicaŽl Moukoumi; Thierry Bťguiristain; Jacques Ranger; Jacques Berthelin
Physical demands of firefighter search and rescue in ambient environmental conditions.
This study investigated the physiological responses and limitations to a simulated search and rescue scenario in a high-rise building under ambient conditions. Sixteen firefighters performed the scenario under four conditions: standard duration breathing apparatus (SDBA) and 45 mm hose; extended duration breathing apparatus (EDBA) and 45 mm hose; SDBA and 70 mm hose; EDBA and 70 mm hose. Core temperature, skin temperature and heart rate were monitored. In four of 32 trials the casualty was rescued; the remainder of the trials were terminated for safety, high core temperature or shortage of air. Final core temperature and heart rate were higher in the EDBA (39.1 degrees C; 72% heart rate reserve (HRR)) than SDBA conditions (38.6 degrees C; 67%HRR). No differences were observed between hose sizes. The scenario proved too onerous to complete successfully in the majority of cases. Replacing SDBA with EDBA eliminates air supply as a limiting factor, but brings with it challenges of managing thermal strain. PMID:18568961
Richmond, V L; Rayson, M P; Wilkinson, D M; Carter, J M; Blacker, S D
Beyond mental health: an evolutionary analysis of development under risky and supportive environmental conditions: an introduction to the special section.
Evolutionary approaches to behavior have increasingly captured the attention and imagination of academics and laypeople alike. One part of this trend has been the increasing influence of evolutionary theory in developmental science. The articles in this special section of Developmental Psychology attempt to demonstrate why an evolutionary analysis is needed to more fully understand the contexts and contingencies of development. The 3 theoretical articles articulate the core evolutionary logic underlying conditional adaptation (and maladaptation) to both stressful and supportive environmental conditions over development. These theoretical articles are then followed by 9 empirical articles that test these evolutionary-developmental theories and hypotheses. Finally, 6 commentaries evaluate the prospects, pitfalls, and implications of this body of work. PMID:22545847
Ellis, Bruce J; Bjorklund, David F
Abundance of broad bacterial taxa in the sargasso sea explained by environmental conditions but not water mass.
To explore the potential linkage between distribution of marine bacterioplankton groups, environmental conditions, and water mass, we investigated the factors determining the abundance of bacterial taxa across the hydrographically complex Subtropical Convergence Zone in the Sargasso Sea. Based on information from 16S rRNA gene clone libraries from various locations and two depths, abundances of the predominant taxa (eubacteria, Archaea, Alphaproteobacteria, Gammaproteobacteria, Bacteroidetes, and the Roseobacter, SAR11, and SAR86 clades) were quantified by real-time PCR. In addition, the abundances of Synechococcus, Prochlorococcus, and picoalgae were determined by flow cytometry. Linear multiple-regression models determining the relative effects of eight environmental variables and of water mass explained 35 to 86% of the variation in abundance of the quantified taxa, even though only one to three variables were significantly related to any particular taxon's abundance. Most of the variation in abundance was explained by depth and chlorophyll a. The predominant phototrophs, Prochlorococcus and picoalgae, were negatively correlated with phosphate, whereas eubacteria, heterotrophic bacteria, and SAR86 were negatively correlated with nitrite. Water mass showed limited importance for explaining the abundance of the taxonomical groups (significant only for Roseobacter, explaining 14% of the variation). The results suggest the potential for predicting the abundance of broad bacterioplankton groups throughout the Sargasso Sea using only a few environmental parameters. PMID:24561593
SjŲstedt, Johanna; Martiny, Jennifer B H; Munk, Peter; Riemann, Lasse
Environmental conditions in the Donggi Cona lake catchment, NE Tibetan Plateau, based on factor analysis of geochemical data
NASA Astrophysics Data System (ADS)
We present a methodological approach for the characterization of spatial variations of environmental and transport conditions based on geochemical data. We analyzed the geochemical characteristics of terrestrial sediments on an alluvial fan and adjacent areas in the eastern part of the Donggi Cona catchment. The geochemical characteristics of the sediment samples were measured using X-ray fluorescence spectroscopy. A factor model based on nine elements (Sr, Rb, Zn, Fe, Mn, V, Ti, Ca and K) gave the best results using factor analysis. Our results show that factor analysis of geochemical data can explain spatial variations in the catchment, even within a relatively small area with more or less constant climatological conditions. The four most important factors of our model explain 68.4% of the total variance within the dataset. The four factors represent a carbonate, weathering and two redox condition signals, respectively. The spatial distribution of factor loadings points to regions with specific environmental conditions. These regions show a certain carbonate input or production (factor 1), specific weathering rates (factor 2) or specific redox conditions (factors 3 and 4). The factor loadings of the first and second factor are used to reclassify the data into four groups, being dune, loess, lake and fluvial gravel sediments. This reclassification confirms or improves the prior field classification in 70% of all cases. For 23% of the samples, the model gave a different interpretation. The factor loadings in these cases represent the origin of the material rather than its present sediment type, thereby giving valuable information about sediment provenance. Since the third and fourth factor seem more dependent on location, they do not differentiate between different sediment types. Multivariate statistics of the geochemistry of terrestrial sediments (i) allows the subdivision of samples into different sediment types, (ii) indicates dominant regions for weathering, carbonate production and manganese washout and (iii) gives suggestions about the provenance of the sediments. This is the first detailed study of geochemical parameters on the Tibetan Plateau not focusing on lake cores, resulting in a spatial characterization of the local geochemistry. This gives insight in the sediment transport connections between the catchment and the lake, illustrating the value of terrestrial sediments as additional indicator of environmental variations.
IJmker, Janneke; Stauch, Georg; Hartmann, Kai; Diekmann, Bernhard; Dietze, Elisabeth; Opitz, Stephan; WŁnnemann, Bernd; Lehmkuhl, Frank
Mars-Relevant Environmental Conditions at the Lakes of Licancabur Volcano, Bolivia
NASA Astrophysics Data System (ADS)
In the Bolivian Altiplano, a number of environmental variables combine to produce some of the most exotic and poorly understood lacustrine environments on Earth. In a cold, arid environment with extreme ultraviolet flux, these lakes provide a habitat for biology and a proxy for the study of potentially analogous martian environments. Here, we present new data on the physical, chemical environment of three such lakes at Licancabur Volcano, Bolivia and explore the quantitative basis for an analogy to Mars. Licancabur (22į50`'S, 67į53`'W) is a large, dormant volcano on the western edge of the Bolivian Altiplano at the border with Chile. Two hypersaline lakes, Laguna Blanca and Laguna Verde, are located at the volcano`'s 4300 m base. Within the past thirty years, these two were connected as a single reservoir, but local climate-driven evaporation (precipitation <100 mm/y, evaporation >1000 mm/y) has resulted in two topographically and chemically distinct bodies connected by a small stream. At nearly 6000 m, the small crater lake of Licancabur is one of the highest known and least explored on Earth. While sub-freezing average air temperature and extreme ultraviolet flux create an environment similar to the surface of Mars, the lake harbors a small biological community and is ice-covered only part of the year.
Hock, A. N.; Cabrol, N. A.; Grin, E. A.; Kovacs, G. T; Rothschild, L. J.; Parazynski, S. E.; Prufert-Bebout, L.
Influence of environmental conditions, bacterial activity and viability on the viral component in 10 Antarctic lakes.
The influence of biotic and environmental variables on the abundance of virus-like particles (VLP) and lysogeny was investigated by examining 10 Antarctic lakes in the Vestfold Hills, Antarctica, in the Austral Spring. Abundances of viruses and bacteria and bacterial metabolic activity were estimated using SYBR Gold (Molecular Probes), Baclight (Molecular Probes) and 6-carboxy fluorescein diacetate (6CFDA). Total bacterial abundances among the lakes ranged between 0.12 and 0.47 x 10(9) cells L(-1). The proportion of intact bacteria (SYTO 9-stained cells) ranged from 13.5% to 83.5% of the total while active (6CFDA-stained) bacteria ranged from 33% to 116%. Lysogeny, as determined with Mitomycin C, was only detected in one of the lakes surveyed, indicating that viral replication was occurring predominantly via the lytic cycle. Principal component analysis and confirmatory correlation analysis of individual variables showed that high abundances of VLP occurred in lakes of high conductivity with high concentrations of soluble reactive phosphorus and dissolved organic carbon. These lakes supported high concentrations of chlorophyll a, intact bacteria, rates of bacterial production and virus to bacteria ratios. Thus, it was suggested that viral abundance in the Antarctic lakes was determined by the trophic status of the lake and the resultant abundance of intact bacterial hosts. PMID:18031540
SšwstrŲm, Christin; Pearce, Imojen; Davidson, Andrew T; Rosťn, Peter; Laybourn-Parry, Johanna
Influence of Cultivar and Environmental Conditions on the Triacylglycerol Profile of Hazelnut (Corylus avellana L.).
The oil of several hazelnut (Corylus avellana L.) samples was extracted and evaluated for their triacylglycerol (TAG) composition. Trials were conducted in two Portuguese localities (Vila Real and Felgueiras) during three consecutive years and involved a total of 19 cultivars. The samples were analyzed by reversed-phase high-performance liquid chromatography with evaporative light-scattering detection. Sample preparation was fast and simple, consisting only of the dissolution of the oil in acetone, homogenization, and filtration, allowing this technique to be suitable for routine analyses. All samples presented a similar qualitative profile composed of eleven compounds: LLL, OLL, PLL, OOL, POL, PPL, OOO, POO, PPO, SOO and PSO (P, palmitoyl; S, stearoyl; O, oleoyl; and L, linoleoyl). The main components were OOO, LOO, and POO, reflecting the high content of oleic acid in hazelnut oils. A total of 79 different samples were studied, and the obtained data were statistically analyzed. Significant differences were verified in canonical variate plots when cultivars were grouped by country of origin. In general, the American cultivars were richer in TAGs with saturated fatty acids moieties, and the group of French, German, and English cultivars was richer in TAGs containing linoleic acid moieties. Differences were also significant when cultivars were grouped by year of production, showing that besides genetic factors, the TAG composition can be influenced by environmental factors. PMID:16417303
Amaral, Joana S; Cunha, Sara C; Santos, Alberto; Alves, M Rui; Seabra, Rosa M; Oliveira, Beatriz P P
Tocopherol concentration in almond oil: genetic variation and environmental effects under warm conditions.
The concentration of the different tocopherol homologues in almond kernel oil was determined in 17 almond cultivars grown in two different experimental orchards, in Spain and Morocco. The three main homologues showed a large variability, ranging from 210.9 to 553.4 mg/kg of oil for ?-tocopherol, from 4.64 to 14.92 mg/kg for ?-tocopherol, and from 0.2 to 1.02 mg/kg for ?-tocopherol. The year effect was significant, independent of the experimental site, for all homologues and total tocopherol, the values of ?-tocopherol, ?-tocopherol, and total tocopherol being higher in 2009 than in 2008, whereas the value of ?-tocopherol was higher in 2008. The location effect was also significant, the values of ?- and ?-tocopherol being higher in Spain than in Morocco, whereas for ?-tocopherol the location effect was dependent on the genotype. These effects could not be explained by the temperature differences between sites, but probably other undetermined environmental factors might explain the effect of the location, such as rainfall and irrigation supplementation during fruit growing and ripening. PMID:21524140
Kodad, Ossama; EstopaŮŠn, Gloria; Juan, Teresa; Mamouni, Ali; Socias i Company, Rafel
Environmental Conditions in Water Storage Drums and Influences on Aedes aegypti inTrinidad, West Indies
Water storage drums are often a primary breeding site for Aedes aegypti in developing countries. Habitat characteristics can impact both adult and larval fitness and survival, which may potentially influence arbovirus transmission. Our objective was to compare fundamental environmental differences in water drums based on the presence or absence of larvae in Trinidad. Drums were categorized according to the larval status, and if the drum was constructed of steel or plastic. Water samples were analyzed for ammonium, nitrate, and soluble reactive phosphorus (SRP). Continuous surface water temperatures were also recorded. Nutrient concentrations were considerably lower than those reported for other container breeding mosquitoes. No nutrient measured differed in concentration between drums positive compared to those that were negative for the presence of Aedes aegypti larvae. Levels of SRP and ammonium in steel drums were significantly lower than in plastic water drums. Both maximum and minimum surface temperatures were significantly lower in drums positive for the presence of larvae than in drums without larvae. Water temperatures in March and May were warmer than during October sampling periods. Larval presence is likely dependent upon the interaction among multiple biotic and abiotic factors. Despite appearance, not all water storage drums are equally suitable for Aedes aegypti development. Exposing water storage drums to direct sunlight or increased heat may be used in conjunction with sealing containers to reduce production of Aedes aegypti when draining and chemical treatment are impractical.
Hemme, Ryan R.; Tank, Jennifer L.; Chadee, Dave D.; Severson, David W.
A comparison of modern and fossil ostracods from Frasassi Cave system (northeastern Apennines, Italy) to infer past environmental conditions
NASA Astrophysics Data System (ADS)
Cave water and sediments from an extensive sulfidic, chemioautotrophic subterranean ecosystem in the hypogenic karst complex of Frasassi (northeastern Apennines of Italy) was analysed for modern and fossil ostracode assemblages. 22 extant and 16 extinct ostracode species make of this continental sulphidic ecosystem one of the richest worldwide. Both modern and fossil assemblages show the expected pattern of species diversity after the simulation procedure for taxonomic distinctness, which indicates no major extinction events since the Pleistocene. Extant species display patchy distribution according to habitat heterogeneity within the sulphidic environment. Fossil assemblages from a 3 m thick fluvial deposit trapped near the entrance of the Caverna del Carbone (CDC) at about 30 m above present river level, and a fine sand deposit resting at about the same elevation in Sala Duecento (SDS) within the Grotta Grande del Vento preliminarily dated with OSL at 111Ī17 ka are being investigated. The former deposit has yet to be dated but it represents probably a normal stratigraphic succession spanning a few tens of kyr, which was deposited when the cave entrance was at the reach of fluvial flooding, potentially recording the transition from the last interglacial Riss-WŁrm to the glacial WŁrm. Sediment samples from the SDS site yielded an ostracode assemblage represented by 12 species with a d18O signature of -5Č and a well-diversified palinoflora assemblage indicating a transitional condition between steppe and temperate forest. The top sediment from the CDC site is characterized by a less diversified ostracode assemblage represented by 8 species, d18O of -3Č, and a poorly diversified palinoflora dominated by herbaceous plants and lesser pines, indicating a colder environment in the early stage of the last glacial. Additional information on the geometric morphometry approach of B-splines method applied to extant and fossil specimens of the hypogean Mixtacandona ostracode was used to identify microevolutionary patterns and environmentally cued variation. Analyses indicate the presence of one morphotype of a new species A of the group Mixtacandona riongessa, and three distinctive morphotypes of a species B of the group M. laisi-chappuisi occurring in stratigraphically distinct fluvial-cave sediments. Apparent difference in the disparity level between these species could be associated with their survival in different environmental conditions. Species A is found nowadays living exclusively in sulphidic cave waters, and was present in the system since at least the end of the last interglacial. The extraordinary high taxonomic and morphological diversity of ostracods reflects in situ evolutionary processes that have occurred under the cumulative effect of high environmental energy availability of subterranean sulphidic ecosystems, heterogeneous environmental conditions, and spatial and temporal isolation.
Iepure, S.; Namiotko, T.; Montanari, A.; Brugiapaglia, E.; Mainiero, M.; Mariani, S.; Fiebig, M.
Investigations of chemical fraction of Co and Ni in industrial fly ash and mobility of metals in environmental conditions.
The quantitative evaluation of chemical fraction of Co and Ni in the industrial fly ash by methods of five step sequential extraction was carried out in order to characterize metal mobility in environmental conditions. The research involved (i) water-soluble (pH=7), (ii) acid-soluble (pH=5), (iii) oxide, (iv) sulfide and (v) residue metal fractions. It was discovered, that the total extraction of the studied metals from fly ash to solutions take place in the following quantities Co - 35.5 and Ni - 153.0mgkg(-1). The investigations of chemical fractions proved that the subject metals occur mainly in fly ash as: oxide (Co - 7.0, Ni - 28.5mgkg(-1)) and residue (Co - 11.5, Ni - 42.5mgkg(-1)) as well as sulfide (Co - 8.5, Ni - 46.5mgkg(-1)). Low concentrations of metals for water-soluble fraction (Co - 0.7, Ni - 1.2mgkg(-1)) and acid-soluble fraction (Co - 4.5, Ni - 23.5mgkg(-1)) were observed. The fractions of Co and Ni leachable from the ash in environmental conditions contain: 24.0% (Co) and 23.3% (Ni) of metal total amount in the industrial fly ash. The obtained mobility parameter of Co and Ni can be applied to estimate the concentration increase of mobile and hardly mobile forms of these metals in soil polluted with the ash. PMID:17150241
Soco, Eleonora; Kalembkiewicz, Jan
Development of stress resistance in Staphylococcus aureus after exposure to sublethal environmental conditions.
The ability of Staphylococcus aureus to develop stress resistance responses was investigated. Exponential growth phase cells of S. aureus CECT 4459 were exposed to sublethal conditions (acid and alkaline pH, hydrogen peroxide, and heat) and then the acquisition of resistance to acid (pH 2.5), alkali (pH 12.0), hydrogen peroxide (50mM), and heat (58 degrees C) was determined. Conditions resulting in the maximum development of homologous resistance (tolerance to the same stress), while preventing lethal effects in the population, were pH 4.5 (2h), pH 9.5 (30 min), 0.05 mM H(2)O(2) (30 min), and 45 degrees C (2h). Under these adaptation conditions, times for the first decimal reduction (TFDC) to a lethal treatment at acid pH, alkaline pH, hydrogen peroxide, and heat were increased by a factor of 1.6, 2, 2, and 6, respectively. The presence of chloramphenicol or rifampicin in the adaptation medium completely abolished the increase in homologous resistance to acid pH and to hydrogen peroxide. By contrast, the development of homologous resistance to alkaline pH resulted independently of the presence of either chloramphenicol or rifampicin. S. aureus heat resistance increased in the presence of the inhibitors during the heat shock, but only partially. In some cases, the exposure to a given stress induced cross-protection against other agents. Protective combinations of sublethal stress and lethal agents were: acid pH-heat, acid pH-hydrogen peroxide, alkaline pH-hydrogen peroxide, heat-acid pH, and heat-hydrogen peroxide. These combinations of agents applied sequentially should be avoided in food-processing environments. PMID:20303608
CebriŠn, G; Sagarzazu, N; PagŠn, R; Condůn, S; MaŮas, P
The effect of technetium-99 and environmental conditions on soybean physiology
Technetium-99 is considered a long-term risk of nuclear energy because it has a long half-life, mass 99 is produced at a high yield during nuclear fission, and Tc-99 is taken up readily by aquatic and terrestrial organisms. Plants are an important intermediate of Tc-99 food chain transfer to animals and humans. The present study investigated adenosine triphosphate (ATP), photosynthesis and structural responses of intact soybean seedlings [Glycine max (L.) Merr. cv. Williams] to micromolar amounts of Tc-99 under different ambient light levels. Adenosine triphosphate was measured directly in primary leaf extract after 6 d of exposure to Tc at varying concentrations (up to 5 {mu}M Tc-99). The results indicated that under full light conditions (320 {mu}mol photon m{sup {minus}2}s{sup {minus}1}), soy bean primary leaves contained nanomolar concentrations of ATP almost twice as high as for untreated plants. With a reduction of light intensity by 50%, primary leaf pertechnetate uptake and leaf ATP content were reduced regardless of Tc-99 exposure levels. Gas exchange measurements with a Li-Cor 6200 Portable Photosynthesis system indicated a significant decline of photosynthetic rate and a higher internal CO{sub 2} accumulation under full light conditions, while stomatal conductance decreased as a function of Tc-99 concentration. Several possible mechanisms of Tc interaction with chloroplast ultrastructure are proposed. A hypothesis related to the metabolic behavior of Tc in higher plants is presented. 34 refs., 6 figs.
Degenkolb, S.J.; Neel, J.W.; Papin, P.J. [Scripps Clinic and Research Foundation, La Jolla, CA (United States)
Organic-coated silver nanoparticles in biological and environmental conditions: fate, stability and toxicity.
This review paper presents the overview of processes involved in transformation of organic-coated silver nanoparticles (AgNPs) in biological systems and in the aquatic environment. The coating on AgNPs greatly influences the fate, stability, and toxicity of AgNPs in aqueous solutions, biological systems, and the environment. Several organic-coated AgNP systems are discussed to understand their stability and toxicity in biological media and natural water. Examples are presented to demonstrate how a transformation of organic-coated AgNPs in an aqueous solution is affected by the type of coating, pH, kind of electrolyte (mono- or divalent), ionic strength, organic ligands (inorganic and organic), organic matter (fulvic and humic acids), redox conditions (oxic and anoxic), and light. Results of cytotoxicity, genotoxicity, and ecotoxicity of coated AgNPs to food chain members (plants, bacteria, and aquatic and terrestrial organisms) are reviewed. Key factors contributing to toxicity are the size, shape, surface coating, surface charge, and conditions of silver ion release. AgNPs may directly damage the cell membranes, disrupt ATP production and DNA replication, alternate gene expressions, release toxic Ag(+) ion, and produce reactive oxygen species to oxidize biological components of the cell. A progress made on understanding the mechanism of organic-coated AgNP toxicity using different analytical techniques is presented. PMID:24406050
Sharma, Virender K; Siskova, Karolina M; Zboril, Radek; Gardea-Torresdey, Jorge L
Effects of environmental conditions on growth and survival of Salmonella in pasteurized whole egg.
This study investigated the influence of three parameters (time, temperature and NaCl concentration) on survival and four parameters (temperature, NaCl and lysozyme concentrations and pH) on growth of Salmonella enterica serovar Enteritidis (S. Enteritidis) in pasteurized whole egg (PWE). Doehlert uniform shell design was employed to choose conditions for trials and data was fitted to polynomial models and were presented as estimated response surfaces. A model for prediction of reduction of S. Enteritidis in PWE within temperatures between 50 and 58įC, NaCl concentrations of 0-12%, and heating times between 30 and 210s and a model for prediction of growth rate of S. Enteritidis in PWE in the temperature range of 1-25įC, NaCl concentration of 0-12%, pH between 5 and 9, and lysozyme concentrations of 107-1007U/mg proteins were developed. The maximum reduction condition was 58įC, 0% of NaCl at a fixed heating time of 120s, while maximum growth rate was estimated at 25įC and 0% of NaCl. pH and lysozyme concentration were shown not to influence growth performance significantly in the range of values studied. Results inform industry of the optimal pasteurization and storage parameters for liquid whole egg. PMID:24703437
Jako?i?n?, Děiuginta; Bisgaard, Magne; Hervť, GaŽlle; Protais, Jocelyne; Olsen, John Elmerdahl; Chemaly, Marianne
Control of environmental conditions at the lower boundary of field lysimeters
NASA Astrophysics Data System (ADS)
Lysimeters are vessels containing disturbed or undisturbed soil, embedded completely in soil with its top even to the soil surface. At the bottom of lysimeters, the soil is cut off from the parent soil, and the lower boundary of lysimeters is usually exposed to atmospheric pressure. For this reason, soil water conditions may be different than of the surrounding soil. This may affect the soil-water conditions throughout the soil profile in comparison to the surrounding soil. To avoid this problem, lysimeters with a construction depth much more than the expected rooting depth should be used or a suction-controlled drainage system needs to be installed at the bottom of lysimeters. Not only the water flow but also the heat flow in the lysimeter is affected by the isolation of the soil and by the fact that the soil at the bottom of the lysimeter is cut off from the surrounding area. However, since now only a few studies have dealt with this issue. This is surprising because the soil thermal regime controls both growth and function of roots and shoots. Therefore, a new design for an automatic control of soil temperature at the lower boundary of large, undisturbed field lysimeters was developed. The objective of the intended talk is to present and evaluate the design and functionality of this new setup.
Schwšrzel, Kai; Podlasly, Christian
Intracellular pH Recovery Rates in Bivalve Hemocytes Following Exposure to Acidic Environmental Conditions
NASA Astrophysics Data System (ADS)
Predictions of ocean acidification effects upon carbonate shell-forming species have caused great concern for the future of shellfisheries. Nevertheless, bivalve species inhabiting an estuarine environment have evolved in these environments with fluctuating pH levels. Previous experimental studies conducted in our laboratory have demonstrated the ability of oyster hemocytes to maintain intracellular homeostasis under acidic external conditions. However, little information is known of this homeostatic mechanism in other molluscan shellfish species present in these same habitats. In the current study we propose to determine if other bivalve species of aquaculture interest also possess this intracellular regulation by applying an in vitro hemocyte pH-recovery assay, previously developed for oysters, on the northern quahog, Mercenaria mercenaria, the blue mussel, Mytilus edulis, and the softshell clam, Mya arenaria. Preliminary results from the determination of initial intracellular pH levels, the initial step in the rate recovery assay, indicated a pH range between 7.0-7.4. This range was comparable to initial values measured in oysters, and consistent with data reported in the current literature. The second step of the hemocyte pH-recovery assay involves exposing oyster hemocytes to acidic external conditions and measuring the ability of the hemocyte intracellular pH to maintain homeostasis (i.e. recovery rate). Results from the recovery rate process will be presented.
Croxton, A.; Wikfors, G. H.
Individual differences in impulsive and risky choice: Effects of environmental rearing conditions.
The present experiment investigated early-rearing environment modulation of individual differences in impulsive and risky choice. Rats were reared in an isolated condition (IC; n=12), in which they lived alone without novel stimuli, or an enriched condition (EC; n=11), in which they lived among conspecifics with novel stimuli. The impulsive choice task involved choices between smaller-sooner (SS) versus larger-later (LL) rewards. The risky choice task involved choices between certain-smaller (C-S) versus uncertain-larger (U-L) rewards. Following choice testing, incentive motivation to work for food was measured using a progressive ratio task and correlated with choice behavior. HPLC analyses were conducted to determine how monoamine concentrations within the prefrontal cortex (PFC) and nucleus accumbens (NAC) related to behavior in different tasks. IC rats were more impulsive than EC rats, but they did not differ in risky choice behavior. However, choice behavior across tasks was significantly correlated (i.e., the more impulsive rats were also riskier). There were no group differences in monoamine levels, but noradrenergic and serotonergic concentrations were significantly correlated with impulsive and risky choice. Furthermore, serotonin and norepinephrine concentrations in the NAC significantly correlated with incentive motivation and the timing of the reward delays within the choice tasks. These results suggest a role for domain general processes in impulsive and risky choice and indicate the importance of the NAC and/or PFC in timing, reward processing, and choice behavior. PMID:24769268
Kirkpatrick, Kimberly; Marshall, Andrew T; Smith, Aaron P; Koci, Juraj; Park, Yoonseong
Effects of wearing compression garments on thermoregulation during simulated team sport activity in temperate environmental conditions.
Anecdotal evidence suggests compression garments (CGs) are being worn underneath normal playing attire during team sports. Wearing CGs as a baselayer could possibly increase heat storage, and so this field study investigated the effects of wearing CGs, comprising knee-length shorts and short-sleeved top underneath normal match-day attire (COMP), versus normal match-day attire alone (NORM) on thermoregulation during simulated team sport activity. Ten match-fit field hockey players twice performed 4x15min exercise bouts consisting of repeated cycles of intermittent, varied-intensity 20m shuttle running (Loughborough intermittent shuttle test), once in COMP and once in NORM. Testing was conducted in an indoor gymnasium (ambient conditions: approximately 17 degrees C, approximately 60% relative humidity). Participants acted as their own controls. Heart rate (HR), 15m sprint time, ratings of perceived exertion (RPE), blood lactate concentration, sweat rate and body core temperature (T(core)) were similar between trials (p>0.05). Mean skin temperature (T(skin)) was significantly higher in COMP than NORM (p<0.05). Overall, CGs worn as a baselayer during simulated team sport exercise in temperate ambient conditions had no thermoregulatory benefits nor any detrimental effects on T(core), physiological performance or dehydration. However, the higher T(skin) may affect individual preference for wearing CGs as an undergarment during team sports. PMID:18078787
Houghton, Laurence A; Dawson, Brian; Maloney, Shane K
Environmental education as preparation people for life in conditions of global changes imbalanced Nature
NASA Astrophysics Data System (ADS)
The Regional Teacher Training Centre in Skierniewice is one of 49 public, accredited institutions in Poland. It is responsible for organizing of support of schools, institutions, networks of teachers and school managers for cooperation and self education, organizing and conducting forms of in-service training, giving methodological councils and disseminating examples of good practice. I present one example of how Environmental Education has been imparted to school students and their teachers through outdoor activities as part of the learning process. An Environmental Education Program, 'On Bolimov Nature Preserve Trails' has been organized regularly since 2001. The Bolimov Nature Preserve is a protected area in central Poland, situated between two agglomerations: capital city Warsaw to the East and industrial city Lodz to the West. It was established to protect an unique ecosystem on the Rawka River banks from human activity and harmful external factors. Pine tree forests, small streams, wetlands, glades are another elements of the park scenery. Walks on the park's trails are a great opportunity to see unique species of flora (more than 40 protected species and many endangered species on verge of extinction) and fauna. For teachers and students the Bolimov Nature Preserve offers educational lessons and events. The main activity is participation of students and teachers in group walk along trails of the park using various tools of orientation: maps, compasses and GPS. Along the paths they learn recognition of forms of terrain, identification of living species (using flora&fauna guides, magnifying glasses), measuring components of weather (using weather atlases, thermometers, anemometers) as well as preparation of soil profile. A survey is conducted after each such program. A statistical analysis of the survey data reveals that each year more and more students representing all levels of education from primary to upper secondary levels and their teachers are involved in this enterprise. For all participating in these walks it is great opportunity to observe how the Nature is functioning without much man-kind interference, pure, untouched and imbalanced. They can observe the untouched river banks, non regulated and meandering in its own way. They can recognize new species which are appearing every year on non cultivated glades, around overgrowing mid-forest lakes or on wetlands. They can observe traces of beavers' work: dams, cut trees, beaver lodges built on small streams flowing through the forest. Also the nests of unique black storks are possible to see. They can measure and observe how the climate is changing and how it varies in different ecosystems (forest, glade, river, wetlands) untouched by humans. They can learn that Nature can exists itself without human interference and it becomes more diverse and rich. It is necessary to teach students to the correct understand the changes in Nature, explain how are changing the living and non-living nature, what is the man-made imbalances of Nature and also how to prepare people for climate change. Each year almost 700 - 1000 students and about 100 teachers participate in this ecological learning process. Outdoor education, observations and experimentations are crucial issues of national school curricula referring to all educational levels which is successfully addressed by this program.
Dabrowska, A. E.
Evaluation of contact heat thermal threshold testing for standardized assessment of cutaneous nociception in horses - comparison of different locations and environmental conditions
Background The aim of the study was to evaluate the performance of contact heat thermal stimulation in horses at different body sites and under different environmental conditions and different test situations. Five warm-blood horses were equipped with the thermal probe located on the skin of nostril (N), withers (W) or coronary band (C). Skin temperature and reaction temperature (thermal threshold) at each location were measured and percent thermal excursion (% TE?=?100 * (threshold temperature - skin temperature)/(cut-out temperature - skin temperature) was calculated. Environmental conditions were changed in partial random order for all locations, so each horse was tested in its familiar box stall and stocks, in the morning and evening and at warm and cold ambient temperatures. Type of reaction to the stimulus and horseís general behaviour during stimulation were recorded. The stimulation sites were examined for the occurrence of possible skin lesions. Results Skin temperatures were significantly different during warm and cold ambient temperatures at all three locations, but remained constant over repeated stimulation. An obvious response to stimulation before reaching cut-out temperature could be detected most frequently at N and W in boxes during warm ambient temperatures. The most frequent type of reaction to thermal stimulation at the nostril was headshaking (64.6%), skin twitching at the withers (82.9%) and hoof withdrawal at the coronary band (79.2%). Conclusion The outcome of thermal threshold testing depended on ambient temperature, stimulation site and environment. Best results with the WTT2 in horses were obtained at the nostrils or withers in a familiar environment at warm ambient temperatures.
Optimizing environmental conditions for mass application of mechano-dwarfing stimuli to Arabidopsis
NASA Technical Reports Server (NTRS)
Obtaining uniform mechano-dwarfing of Arabidopsis thaliana (L.) Heynh. seedlings within dense plantings is problematic. Alternative forms of mechano-stimulation were applied to seedlings in effort to obtain uniform growth reduction compared with undisturbed controls in both greenhouse and controlled growth environments. Arabidopsis grown under low photosynthetic photon flux (PPF) artificial light grew upright with limited leaf expansion, which enhanced mechano-responsiveness compared to that of rosette-growing plants under filtered sunlight or high PPF artificial light. Hypocotyls of seedlings grown at PPFs > 60 micromoles m-2 s-1 elongated less and had 6% less sensitivity to mechanical stress than seedlings grown at PPFs < 60 micromoles m-2 s-1. Fluorescent lamps alone (F) or fluorescent plus incandescent (F+I) lamps were compared for seedling responses to mechanical stress. Under F lighting, hypocotyl elongation was reduced 25% to 40% by twice-daily brush or plate treatments, and brushed seedlings exhibited more growth reduction than did plate treatments. Seedlings grown under F+I lamps exhibited similar stress-induced growth reduction compared to seedlings grown under F only, but stressed F+I seedlings lodged to a greater extent due to excessive hypocotyl elongation. Temperature-response studies using standardized F-only lighting indicated increased hypocotyl elongation but decreased leaf expansion, and decreased mechano-responsivity to brushing over the temperature range from 20 to 28 degrees C. Daylength studies indicated similar degrees of mechano-inhibition of hypocotyl elongation over the daylength range of 12, 16, 20, and 24 hours, whereas fresh weight of stressed seedling shoots declined compared to controls. A combination of environmental growth parameters that give repeatable, visual mechanical dwarfing of Arabidopsis include low-PPF fluorescent lighting from 55 to 60 micromoles m-2 s-1, ambient temperatures from 22 to 25 degrees C, and twice-daily brush treatments.
Montgomery, Jill A.; Bressan, Ray A.; Mitchell, Cary A.
Relationship between suicide and myocardial infarction with regard to changing physical environmental conditions
NASA Astrophysics Data System (ADS)
In recent years, the possible association of changes in mortality from cardiovascular disease and myocardial infarction (MI) and deaths related to violence and the suicide rate has been repeatedly discussed. This study examined the relationship between cosmic physical changes (solar, geomagnetic and other space activity parameters) and changes in the total number of in-hospital and MI-related deaths and deaths from suicide to determine if a relationship exists between the distribution of total and MI-related deaths with suicide over time; some differences in the serotonergic mechanisms involved in the pathogenesis of MI and suicide were also taken into account. All suicides ( n=2359) registered in the State of Israel from 1981 to 1989 (108 months) were analysed and compared with the total number of deaths ( n=15601) and deaths from MI ( n=1573) in a large university hospital over 180 months (1974 1989). The following were the main features of the Results. (1) Monthly suicide rate was correlated with space proton flux ( r=0.42, P=0.0001) and with geomagnetic activity ( r=-0.22, P=0.03). (2) Total hospital and MI-related deaths were correlated with solar activity parameters ( r=0.35, P<0.001) and radiowave propagation ( r=0.52-0.44, P<0.001), an with proton flux ( r=-0.3 to -0.26, P<0.01). (3) Monthly suicide distribution over 108 months was correlated with MI ( r=-0.33, P=0.0005) and total hospital mortality ( r=-0.22, P=0.024). (4) Gender differences were prominent. We conclude that the monthly distributions of suicides and deaths from MI are adversely related to many environmental physical parameters and negatively correlated with each other.
Stoupel, Eliahu; Abramson, Eugeny; Sulkes, Jaqueline; Martfel, Joseph; Stein, Nechama; Handelman, Meir; Shimshoni, Michael; Zadka, Pnina; Gabbay, Uri
The effect of environmental conditions on biofilm formation of Burkholderia pseudomallei clinical isolates.
Burkholderia pseudomallei, a Gram-negative saprophytic bacterium, is the causative agent of the potentially fatal melioidosis disease in humans. In this study, environmental parameters including temperature, nutrient content, pH and the presence of glucose were shown to play a role in in vitro biofilm formation by 28 B. pseudomallei clinical isolates, including four isolates with large colony variants (LCVs) and small colony variants (SCVs) morphotypes. Enhanced biofilm formation was observed when the isolates were tested in LB medium, at 30 įC, at pH 7.2, and in the presence of as little as 2 mM glucose respectively. It was also shown that all SVCs displayed significantly greater capacity to form biofilms than the corresponding LCVs when cultured in LB at 37 įC. In addition, octanoyl-homoserine lactone (C(8)-HSL), a quorum sensing molecule, was identified by mass spectrometry analysis in bacterial isolates referred to as LCV CTH, LCV VIT, SCV TOM, SCV CTH, 1 and 3, and the presence of other AHL's with higher masses; decanoyl-homoserine lactone (C(10)-HSL) and dodecanoyl-homoserine lactone (C(12)-HSL) were also found in all tested strain in this study. Last but not least, we had successfully acquired two Bacillus sp. soil isolates, termed KW and SA respectively, which possessed strong AHLs degradation activity. Biofilm formation of B. pseudomallei isolates was significantly decreased after treated with culture supernatants of KW and SA strains, demonstrating that AHLs may play a role in B. pseudomallei biofilm formation. PMID:22970167
Ramli, Nur Siti K; Eng Guan, Chua; Nathan, Sheila; Vadivelu, Jamuna
An explosive convective cloud system and its environmental conditions in MJO initiation observed during DYNAMO
NASA Astrophysics Data System (ADS)
unusually large, explosive convective cloud system was observed over the equatorial Indian Ocean on 28 November 2011 during the DYNAMO (Dynamics of the Madden-Julian Oscillation (MJO)) field campaign. The significance of this mesoscale convective system (MCS) is its size and explosive development of cold cloud tops (-96įC) during the initiation of a strong MJO event. Observations from the DYNAMO show that the large MCS developed within a well-defined synoptic-scale cyclonic circulation associated with an equatorial low-pressure system with characteristics of a mixed Rossby-gravity wave that dominated the flow in the DYNAMO array. Prior to the development of the MCS, the equatorial flow was characterized by strong vertical wind shear with low-level westerlies and upper level easterlies. A region of decreased wind shear and enhanced upper level divergence emerged concurrently with the passage of the westward moving mixed Rossby-gravity wave-related low-pressure system and convective activity. In situ sounding observations suggest that widespread deep convection upstream of the large MCS may have contributed to the reduction of the upper level easterlies through vertical momentum transport and convective outflow. Both the reduction in vertical wind shear and enhanced low-level convergence induced by the equatorial low-pressure system created a favorable environment for the rapid development of the MCS. This study examines the development of the MCS and the associated synoptic-scale equatorial low-pressure system within the large-scale MJO circulation using in situ sounding observations from DYNAMO, which provide new insights into the interaction between convection and environmental flow during MJO initiation over the equatorial Indian Ocean.
Judt, Falko; Chen, Shuyi S.
Environmental conditions and biotic interactions influence ecosystem structure and function in a drying stream
Benthic consumers influence stream ecosystem structure and function, but these interactions depend on environmental context. We experimentally quantified the effects of central stoneroller minnows (Campostoma anomalum (Rafinesque) and Meek's crayfish (Orconectes meeki meeki (Faxon)) on benthic communities using electric exclusion quadrats in Little Mulberry Creek before (June) and during (August) seasonal stream drying. Unglazed ceramic tiles were deployed in June and August to measure periphyton and invertebrate abundance, and leafpack decomposition and primary production were also measured in August. Relationships between stoneroller and crayfish density and the size of consumer effects were evaluated with multiple linear regression models. Average chlorophyll a abundance was greater on exposed than exclusion tiles in August, but not in June. Sediment dry mass, periphyton ash-free dry mass (AFDM), and chironomid densities on tiles did not differ among treatments in either period. Leaf packs decayed faster in exposed than exclusion treatments (kexposed = 0.038 ?? 0.013, kexclusion = 0.007 ?? 0.002), but consumer effects were stronger in some pools than others. Leafpack invertebrate biomass and abundance and tile primary productivity did not differ among treatments. Consumer effects on chlorophyll a were related to crayfish and stoneroller density, and effects on chironomid density were related to stoneroller density. These results contrast with a previous exclusion experiment in Little Mulberry Creek that demonstrated strong consumer effects. The influence of stream drying on consumer effects appears to have been reduced by strong spates, underscoring the importance of conducting multi-year studies to determine the magnitude of variability in ecological interactions. ?? US Government: USGS 2010.
Ludlam, J. P.; Magoulick, D. D.
Distribution of Recent Benthic Foraminifera and its Environmental Conditions of Karaikal, Central Coast of Tamil Nadu
NASA Astrophysics Data System (ADS)
Foraminifera have been successful inhabitants of every aquatic environment from deep oceans to brackish water lagoons, estuaries and even rarely in freshwater streams, lakes etc. offshore region of Karaikal the present study has been taken up to enhance the existing knowledge on foraminifera of central coast of Tamil Nadu, India. Totally 21 sediment and water samples were collected from the offshore region. The depth of sample collection in offshore area ranges from 1.5 m to 12 m. Standard procedures adopted for the evaluation of different environmental parameters are incorporated. A total of 33 foraminiferal taxa belonging to 17 genera, 12 subfamilies, 14 superfamilies, and 4 suborders have been identified. In Karaikal , the mean size of the sediments on the foreshore ranges from 1.51 to 2.95 ? indicating the predominance of fine sediments (80-85%) with an admixture of medium-grained sands. Calcium carbonate content is generally found to be directly proportional to the population size in both the estuary and shelf area. It clearly indicates that due to the erosional activities whatever sediments deposited near the Arasalar river in that region are transported to the marine region and were drifted towards northern direction by longshore current, hence the deposition of carbonate in the sediments shows negative correlation. Due to strong high energy environment the current action is more in this region the juvinile forms of A. beccarri, A.tepida, A. dendata, E. crispum, P. calar, and P. nipponica only withstand and the other species are absent. The Correlation between Living vs Dead, Dead Vs Calcium carbonate, Salinity Vs living, Organic matter Vs Living, Organic matter Vs Carbonate content shows positive correlation for all the samples like LT, HT, Beach, River, and Offshore. Even though, all the ecological parameters having good correlation with foraminifera, but the distribution are very less in the study area. M.RAJA Dept.of.Geology University of Madras Chennai,Tamilnadu, INDIA.
Murugan, R.; Gandhi, S.
Evaluation of the performance characteristics of bilayer tablets: Part II. Impact of environmental conditions on the strength of bilayer tablets.
Ambient air humidity and temperature are known to influence the mechanical strength of tablets. The objective of this work is to understand the influence of processing parameters and environmental conditions (humidity and temperature) on the strength of bilayer tablets. As part of this study, bilayer tablets were compressed with different layer ratios, dwell times, layer sequences, material properties (plastic and brittle), first and second layer forces, and lubricant concentrations. Compressed tablets were stored in stability chambers controlled at predetermined conditions (40C/45%RH, 40C/75%RH) for 1, 3, and 5†days. The axial strength of the stored tablets was measured and a statistical model was developed to determine the effects of the aforementioned factors on the strength of bilayer tablets. As part of this endeavor, a full 3?◊?2(4) factorial design was executed. Responses of the experiments were analyzed using PROC GLM of SAS (SAS Institute Inc, Cary, North Carolina, USA). A model was fit using all the responses to determine the significant interactions (p?0.05). Results of this study indicated that storage conditions and storage time have significant impact on the strength of bilayer tablets. For Avicel-lactose and lactose-Avicel tablets, tablet strength decreased with the increasing humidity and storage time. But for lactose-lactose tablets, due to the formation of solid bridges upon storage, an increase in tablet strength was observed. Significant interactions were observed between processing parameters and storage conditions on the strength of bilayer tablets. PMID:22965660
Kottala, Niranjan; Abebe, Admassu; Sprockel, Omar; Bergum, James; Nikfar, Faranak; CuitiŮo, Alberto M
Neural networks for probabilistic environmental prediction: Conditional Density Estimation Network Creation and Evaluation (CaDENCE) in R
NASA Astrophysics Data System (ADS)
A conditional density estimation network (CDEN) is a probabilistic extension of the standard multilayer perceptron neural network (MLP). A CDEN model allows users to estimate parameters of a specified probability density function conditioned upon values of a set of predictors using the MLP architecture. The result is a flexible model for the mean, the variance, exceedance probabilities, prediction intervals, etc. from the specified conditional distribution. Because the CDEN is based on the MLP, nonlinear relationships, including those involving complicated interactions between predictors, can be described by the modeling framework. CDEN models have been applied to a wide range of environmental prediction tasks, such as precipitation downscaling, extreme value analysis in hydrology, wind retrievals from satellites, and air quality forecasting. This paper describes the CaDENCE (Conditional Density Estimation Network Creation and Evaluation) package, which provides routines for creating and evaluating CDEN models in the R programming language. CaDENCE routines are demonstrated on a dataset consisting of suspended sediment concentrations and discharge measurements from the Fraser River at Hope, British Columbia, Canada.
Cannon, Alex J.
Biological and Environmental Initial Conditions Shape the Trajectories of Cognitive and Social-Emotional Development across the First Years of Life
ERIC Educational Resources Information Center
Human development is thought to evolve from the dynamic interchange of biological dispositions and environmental provisions; yet the effects of specific biological and environmental birth conditions on the trajectories of cognitive and social-emotional growth have rarely been studied. We observed 126 children at six time-points from birth to 5Ö
Feldman, Ruth; Eidelman, Arthur I.
Environmental conditions and characteristics of ice supersaturated regions from global field campaigns
NASA Astrophysics Data System (ADS)
Cirrus clouds play important roles in the Earth's climate and weather and their influences extend from the global scale (~30% coverage of the Earth's surface) to the microscale (e.g., interactions with aerosols). Cirrus cloud formation occurs in ice supersaturated regions (ISSRs), where the relative humidity with respect to ice (RHi) is greater than 100%. Recent observations show that cirrus clouds have a very small (~1 km) horizontal median length, yet the origin of such small scale structure is not known. The magnitude of cirrus clouds' radiative forcing is greatly influenced by cloud properties such as the coverage, thickness, ice crystal number concentration and size distribution. The microscale structure of ISSRs is critical for the microphysical processes in cirrus clouds, since the local conditions of ISSRs (e.g. temperature and RHi) influence the properties of ice crystals and their interactions with aerosols. However, the spatial structure of ISSRs and its controlling factors are still unknown below the mesoscale. To this end, we analyzed the spatial structure and environments of ISSRs ó the prerequisite stage of cirrus cloud formation ó based on in situ, high resolution (1 Hz, ~230 m) aircraft observations from 87įN to 67įS from five different field campaigns that span the tropics, mid-latitudes, and polar regions: NSF START08, HIPPO 1-5, PREDICT, TORERO, and DC3 field campaigns. By analyzing a large number (>7000) of individual case studies of ice supersaturated regions, we reveal the patchy nature of ISSRs with their median lengths being very small (~ 1 km) regardless of the location. The patchiness of ISSRs is found to largely correlate with water vapor (H2O) spatial heterogeneities, while the correlations with temperature (T) and vertical velocity (w) heterogeneities are much less dominant. The large influence of H2O heterogeneities on ISSR patchiness not only happens in supersaturated conditions but also extends to subsaturated conditions. The dominance of H2O over the spatial relative humidity field holds from the microscale (~230 m) to the mesoscale (~120 km) over various ranges of temperature (205-302K), water vapor (2-39,000 ppmv) and pressure (133-1,014 hPa). These findings suggest that H2O heterogeneities play crucial roles in determining the RHi spatial heterogeneities even before ISSRs are formed. Neglecting H2O heterogeneities in simplified ISSR evolution schemes results in different ISSR structures than those observed, which in turn changes the predicted properties of cirrus clouds.
Zondlo, M. A.; Diao, M.; Zhang, Q.; DiGangi, J.; O'Brien, A.
Environmental Conditions around Itineraries to Destinations as Correlates of Walking for Transportation among Adults: The RECORD Cohort Study
Introduction Assessing the contextual factors that influence walking for transportation is important to develop more walkable environments and promote physical activity. To advance previous research focused on residential environments and overall walking for transportation, the present study investigates objective environmental factors assessed around the residence, the workplace, the home Ė work itinerary, and the home Ė supermarket itinerary, and considered overall walking for transportation but also walking to work and to shops. Methods Data from the RECORD Study involving 7290 participants recruited in 2007Ė2008, aged 30Ė79 years, and residing in the Paris metropolitan area were analyzed. Multilevel ordinal regression analyses were conducted to investigate environmental characteristics associated with self-reported overall walking for transportation, walking to work, and walking to shops. Results High individual education was associated with overall walking for transportation, with walking to work, and walking to shops. Among workers, a high residential neighborhood education was associated with increased overall walking for transportation, while a high workplace neighborhood education was related to an increased time spent walking to work. The residential density of destinations was positively associated with overall walking for transportation, with walking to work, and with walking to shops, while the workplace density of destinations was positively associated with overall walking for transportation among workers. Environmental factors assessed around the itineraries were not associated with walking to work or to the shops. Conclusion This research improves our understanding of the role of the environments on walking for transportation by accounting for some of the environments visited beyond the residential neighborhood. It shows that workers' walking habits are more influenced by the density of destinations around the workplace than around the residence. These results provide insight for the development of policies and programs to encourage population level active commuting.
Karusisi, Noella; Thomas, Frederique; Meline, Julie; Brondeel, Ruben; Chaix, Basile
Fretting wear of iron, nickel, and titanium under varied environmental conditions
NASA Technical Reports Server (NTRS)
Fretting wear experiments were conducted on high purity iron, nickel and titanium in air under conditions of varied humidity and temperature, and in nitrogen. For iron and titanium, maximum fretting occurred at 10 and 30 percent relative humidity respectively. Nickel showed a minimum in fretting wear at about 10 percent relative humidity. With increasing temperature, all three metals initially showed reduced fretting wear, with increasing wear observed as temperatures increased beyond 200-300 C. For titanium, dramatically reduced fretting wear was observed at temperatures above 500 C, relatable to a change in oxidation kinetics. All three metals showed much less fretting wear in N2 with the presence of moisture in N2 having a proportionally stronger effect than in air.
Bill, R. C.
Formation of Martian Gullies by the Action of Liquid Water Flowing Under Current Martian Environmental Conditions
NASA Technical Reports Server (NTRS)
Images from the Mars Orbiter Camera (MOC) on the Mars Global Surveyor (MGS) spacecraft show geologically young small-scale features resembling terrestrial water-carved gullies. An improved understanding of these features has the potential to reveal important information about the hydrological system on Mars, which is of general interest to the planetary science community as well as the field of astrobiology and the search for life on Mars. The young geologic age of these gullies is often thought to be a paradox because liquid water is unstable at the Martian surface. Current temperatures and pressures are generally below the triple point of water (273 K, 6.1 mbar) so that liquid water will spontaneously boil and/or freeze. We therefore examine the flow of water on Mars to determine what conditions are consistent with the observed features of the gullies.
Heldmann, J. L.; Toon, O. B.; Pollard, W. H.; Mellon, M. T.; Pitlick, J.; McKay, C. P.; Andersen, D. T.
Genetic and environmental relationships between body condition score and milk production traits in Canadian Holsteins.
The objective of this research was to estimate genetic parameters of first-lactation body condition score (BCS), milk yield, fat percentage (Fat%), protein percentage (Prot%), somatic cell score (SCS), milk urea nitrogen (MUN), lactose percentage (Lact%), and fat to protein ratio (F:P) using multiple-trait random regression animal models. Changes in covariances between BCS and milk production traits on a daily basis have not been investigated before and could be useful for determining which BCS estimated breeding values (EBV) might be practical for selection in the future. Field staff from Valacta milk recording agency (Sainte-Anne-de-Bellevue, QC, Canada) collected BCS from Quťbec herds several times per cow throughout the lactation. Average daily heritabilities and genetic correlations among the various traits were similar to literature values. On an average daily basis, BCS was genetically unfavorably correlated with milk yield (i.e., increased milk yield was associated with lower body condition). The unfavorable genetic correlation between BCS and milk yield became stronger as lactation progressed, but was equivalent to zero for the first month of lactation. Favorable genetic correlations were found between BCS with Prot%, SCS, and Lact% (i.e., greater BCS was associated with greater Prot%, lower SCS, and greater Lact%). These correlations were strongest in early lactation. On an average daily basis, BCS was not genetically correlated with Fat% or MUN, but was negatively correlated with F:P. Furthermore, BCS at 5 and 50 d in milk (DIM) had the most favorable genetic correlations with milk production traits over the lactation (at 5, 50, 150, and 250 DIM). Thus, early lactation BCS EBV shows potential for selection. Regardless, this study showed that the level of association BCS has with milk production traits is not constant over the lactation. Simultaneous selection for both BCS and milk production traits should be considered, mainly due to the unfavorable genetic correlation between BCS with milk yield. PMID:22192220
Loker, S; Bastin, C; Miglior, F; Sewalem, A; Schaeffer, L R; Jamrozik, J; Ali, A; Osborne, V
Cultural methods and environmental conditions affecting gray mold and its management in lisianthus.
Gray mold, caused by Botrytis cinerea, severely affects the base of the stems of lisianthus (Eustoma grandiflorum) plants as well as the cut stems left after flowers are harvested. This study examined infection of lisianthus plants by B. cinerea under laboratory and commercial greenhouse production conditions typical for Israel and evaluated cultural methods for manipulating disease development in commercial greenhouses. Although the lower nodes of lisianthus stems are typically infected, in this study, the inherent susceptibility of these nodes was less than that of nodes midway up the stem. Greater light intensity (4,860 lux) was associated with significantly more severe stem wounds than lower light intensities of 140 to 1,020 lux. Lower light intensity (140 lux) was associated with significantly more severe leaf infection. The development of gray mold along leaves toward the stem was slower at 26 degrees C than at 18 to 20 degrees C and was fastest at relative humidity (RH) levels close to saturation (>99%). B. cinerea infection developed in all stem wounds exposed to 65 to 99% RH and at temperatures of 12 to 29 degrees C. Infection severity in stem wounds (measured as lesion length) on whole plants was significantly less at 26 degrees C than at 18 or 22 degrees C, and was significantly higher at 99% RH compared with 70 to 85 and 85 to 95% RH. Severity of gray mold was the greatest at 15 to 22 degrees C and 85 to 99% RH. Under commercial greenhouse conditions, supplemental calcium (Ca(NO3)2) applied in fertigation or as a spray led to moderate yet significant reduction in disease severity. In addition, polyethylene soil cover and the use of buried drip irrigation instead of surface drip irrigation suppressed gray mold significantly on cut stems following harvest. Covering the soil with polyethylene also suppressed gray mold significantly as compared with the common practice of growing lisianthus in bare soil. PMID:19351252
Shpialter, Lena; David, Dalia Rav; Dori, Irit; Yermiahu, Uri; Pivonia, Shimon; Levite, Rahel; Elad, Yigal
Effects of environmental conditions on onset of xylem growth in Pinus sylvestris under drought
Summary We determined influence of environmental factors (air and soil temperature, precipitation, photoperiod) on onset of xylem growth in Scots pine (Pinus sylvestris L.) within a dry inner Alpine valley (750 m a.s.l., Tyrol, Austria) by repeatedly sampling micro-cores throughout 2007-2010 at two sites (xeric and dry-mesic) at the start of the growing season. Temperature sums were calculated in degree-days (DD) ? 5 įC from 1 January and 20 March, i.e. spring equinox, to account for photoperiodic control of release from winter dormancy. Threshold temperatures at which xylogenesis had a 0.5 probability of being active were calculated by logistic regression. Onset of xylem growth, which was not significantly different between the xeric and dry-mesic site, ranged from mid-April in 2007 to early May in 2008. Among most study years statistically significant differences (P < 0.05) in onset of xylem growth were detected. Mean air temperature sums calculated from 1 January until onset of xylem growth were 230 Ī 44 DD (mean Ī standard deviation) at the xeric and 205 Ī 36 DD at the dry-mesic site. Temperature sums calculated from spring equinox until onset of xylem growth showed quite less variability during the four year study period amounting to 144 Ī 10 and 137 Ī 12 DD at the xeric and dry-mesic site, respectively. At both sites xylem growth was active when daily minimum, mean and maximum air temperatures were 5.3, 10.1 and 16.2 įC, respectively. Soil temperature thresholds and DD until onset of xylem growth differed significantly between sites indicating minor importance of root-zone temperature for onset of xylem growth. Although spring precipitation is known to limit radial growth in P. sylvestris exposed to dry inner Alpine climate, results of this study revealed that (i) a daily minimum air temperature threshold for onset of xylem growth in the range of 5-6 įC exists and (ii) air temperature sum rather than precipitation or soil temperature triggers start of xylem growth. Based on these findings we suggest that drought stress forces P. sylvestris to draw upon water reserves in the stem for enlargement of first tracheids after cambial resumption in spring.
Swidrak, Irene; Gruber, Andreas; Kofler, Werner; Oberhuber, Walter
Marine cold seeps and their manifestations: geological control, biogeochemical criteria and environmental conditions
NASA Astrophysics Data System (ADS)
Characteristics of cold seeps at different geologic settings are the subject of this review primarily based on results of the Research Consortium SFB 574. Criteria are drawn from examples on the erosive convergent margin off Costa Rica, the accretionary margin off Chile supplemented by examples from the transform margin of the Golf of Cadiz and the convergent Hikurangi margin off New Zealand. Others are from well-studied passive margins of the Black Sea, the Golf of Mexico, the eastern Mediterranean Sea and the South China Sea. Seeps at all settings transport water and dissolved compounds to the ocean through the seafloor by different forcing mechanism and from different depths of the submerged geosphere (10s of meters to 10s of km). The compounds sustain oasis-type ecosystems by providing bioactive reductants sulfide, methane and hydrogen. Hereby, the interaction between fluid composition, flux rates and biota results in a diagnostic hydrocarbon-metazoan-microbe-carbonate association; currently, well over 100 active sites are known. The single most important reaction is microbially mediated anaerobic oxidation of methane with secondary reactions involving S-biogeochemistry and carbonate mineral precipitation. Seep fluids and their seafloor manifestations provide clues as to source depth, fluid-sediment/rock interaction during ascent, lifetime and cyclicity of seepage events but less so on the magnitude of return flow. At erosive margins, Cl-depleted and B-enriched fluids from clay dehydration provide criteria for source depth and temperature. The upward material flow generates mud volcanoes at the seafloor above the projected location of dehydration at depth. At accretionary margins, fluids are derived from more shallow depths by compaction of sediments as they ride on the incoming oceanic plate; they are emitted through thrust faults. At highly sedimented margins, organic-rich and evaporite-containing strata (when present) determine the final fluid composition, by emitting characteristically gas hydrate-derived methane, brine-associated non-methane hydrocarbons or leached elements and their isotopes (Li, ?7Li, B, Ba) from host sediments. Smectite-illite transformation and associated Cl-depletion from release of interlayer water is a pervasive process at these margins. Rare earth element pattern in conjunction with redox-sensitive metals retained in seep carbonates indicate whether or not they precipitated in contact with oxic bottom water or suboxic fluids; clear environmental characterization, though, currently remains inconclusive. More deeply sourced fluids as in transform margins may be characterized by their 87Sr/86Sr ratios from interaction with oceanic crustal rocks below. Quantification of flow and reliable estimates of total volatile output from fore-arcs remain a challenge to seep research, as does understanding the role of geologically derived methane in the global methane cycle.
Suess, Erwin
Socio-environmental conditions, intestinal parasitic infections and nutritional status in children from a suburban neighborhood of La Plata, Argentina.
We analyzed intestinal parasitic infections in children aged 1-12 years from a poor neighborhood in La Plata, Argentina, and determined the correlations with their nutritional status and socio-environmental conditions. We performed parasitological analyses with anal brushed technique (for Enterobius vermicularis eggs) and fecal samples, employing the techniques of Ritchie, Carles Barthelemy and Willis. The worm burdens of nematodes were estimated by means of Kato Katz technique. Low weight-for-age (underweight), height-for-age (stunting) and weight-for-height (wasting) were calculated based on the 5th centile of the WHO 2006 (children under 5) and CDC 2000 (older children and adolescents) growth references. We also analyzed samples of soil, water, and canine feces and surveyed other domestic and environmental data using structured questionnaires to each child's parents. To associate the parasitological, anthropometric and socio-environmental data, a categorical analysis of principal components (catPCA) was conducted. In the first axis of catPCA, the correlations among socio-environmental variables showed a gradient of "relative welfare". The eigenvectors showed the most influential variables in the analysis were promiscuity (0.0765), father's education (-0.741), crowding (0.727), wastewater disposal (-0.658), mother's education (-0.574), and flooding (-0.409). The 85% of children were parasitized and 79.6% polyparasitized. The 27.7% of children had deficit in some nutritional status indicator, being the stunting the most prevalent deficit (16.8%). There also found parasites in 42% of the dog feces, 53% of the soil samples, and non-pathogenic amoebae in the water samples. The SEV was mainly associated with geohelminths and stunting, especially among the poorest children. The study evidences that living conditions are variable within this population. Part of these variations could be linked to the differences in the extent to which parents are able to use their scant resources to influence their children's morbidity. Further studies need to be done from a qualitative approach. PMID:19577532
Gamboa, MarŪa I; Navone, Graciela T; Orden, Alicia B; Torres, MarŪa F; Castro, Luis E; Oyhenart, Evelia E
Laboratory simulations under martian environmental conditions: water vs. brine flowing over a sloping substrate
NASA Astrophysics Data System (ADS)
There are many observations that indicate that liquid water has been recently flowing on Mars' surface: for example at the present day 10m-scale lobate flows have been observed to occur each spring, termed "recurring slope linae" [1] and kilometre-scale gullies [2] are known to have been active in the recent past (<5 Ma) [3-4]. However, the temperature and pressure are too low, at present for liquid water to be stable, and similar conditions are thought to extend into the recent past. A possible solution to this paradox is that these flows are not pure water, but brines, that are stable under much lower temperature conditions. The static behaviour of brines at low pressure and low temperature has already been investigated [e.g. 5]; however the interaction of such brines flowing over sediment has not yet been explored. In this suite of experiments we aim to repeat the experiments performed by Conway et al. [6], in which a fixed volume of pure water was passed over an unstaturated, cold (-25įC) sediment bed (1x0.5m) at low pressure (7 mbar), but with brines of different concentrations. Our aims are to answer the following questions: 1.Are different quantities of water required to produce flows with the same runout length (measurable from orbit) but mediated by water or brine? 2. Do flows mediated by brine produce any distinctive behaviour or morphology that we could recognise at the martian surface? The suite of experiments are ongoing, but our initial experiments have already shown that for a given quantity of water, brine-flows are able to flow for much greater distances than pure water. Brine mediated flows are more than 4 times wider than their pure water counterparts. Once the flows are complete they freeze - this leaves a trace that has the same tone as the surrounding sediment in the case of water. In the case of brine there are both darker and lighter toned areas depending on the position in the flow-trace. Future analysis includes quantifying the amount of erosion and deposition, and assessing the impact of fluid viscosity on infiltration rate. References cited: [1] McEwan et al. (2011) Science, 333, 740-743. [2] Malin and Edgett (2000) Science, 288, 2330-2335. [3] Reiss et al. (2004) JGR, doi:10.1029/2004JE002251 [4] Schon et al. (2009) Geology, 37, 207-210. [5] Chevrier et al. (2009) JGR, doi :10.1029/2009JE003376 [6] Conway et al. (2011) Icarus, 211, 443-457.
Conway, Susan; Gourronc, Marrine; Patel, Manish
In vitro development of Eucoleus bŲhmi eggs in different environmental conditions.
The development of Eucoleus bŲhmi eggs was evaluated in vitro in order to acquire information on the life cycle of this neglected respiratory nematode affecting canids. Fecal cultures were prepared using fecal samples from a positive dog and maintained at different conditions of temperature (20?Ī?1 and 5?Ī?1†įC) and relative humidity (RH) (85?Ī?5 and 45?Ī?5†%). Egg development was microscopically examined at days +7, +15, and +30. In addition, in order to assess the vitality of eggs maintained at 5?Ī?1†įC for 30†days, these latter cultures were moved, placed at 20?Ī?1†įC and 85?Ī?5†% RH, and observed for further 30 and 40†days. The results showed that at 20?Ī?1†įC and 85?Ī?5†% RH, the totality of eggs completed development in 30†days, while about 26 and 70†% of eggs were already fully developed after 7 and 15†days, respectively. No egg development occurred after 30†days at 5?Ī?1†įC, while 100†% of eggs placed at 5?Ī?1†įC for 30†days and then moved at 20?Ī?1†įC and 85?Ī?5†% RH for further 40†days were found fully developed. PMID:24777343
Perrucci, Stefania; Di Cesare, Angela; Fichi, Gianluca
Study on corrosion behaviors of sintered Nd-Fe-B magnets in different environmental conditions
Nd-Fe-B magnets have outstanding magnetic properties, but their corrosion resistance is poor because the rare-earth-rich phases in them are easily oxidized. In this article, we report an investigation of the corrosion behaviors of sintered Nd-Fe-B magnets with varied compositions in different corrosion conditions. The weight losses of the magnets after corrosion testing were measured after brushing off the corrosion products. The magnetic flux losses of the magnets were measured using a fluxmeter. A scanning electron microscope equipped with an energy dispersive x-ray analysis system was employed to observe the corrosion morphology. It was found that the humid-heat resistance of the magnets was obviously improved by partially substituting Dy for Nd and adding minor Co. The corrosion products and morphologies of Nd-Fe-B magnets for the autoclave test were different from those for the constant humid-heat test. The corrosion rates of the magnets for the former were much slower than for the latter; this is probably because the high-pressure steam led to an oxygen-deficient atmosphere, and the liquid film on the surface of the magnet specimens hindered the diffusion of oxygen into the bulk for the autoclave test.
Li, J. J.; Li, A. H.; Zhu, M. G.; Pan, W.; Li, W.
Computer prediction of human thermoregulatory and temperature responses to a wide range of environmental conditions
NASA Astrophysics Data System (ADS)
A mathematical model for predicting human thermal and regulatory responses in cold, cool, neutral, warm, and hot environments has been developed and validated. The multi-segmental passive system, which models the dynamic heat transport within the body and the heat exchange between body parts and the environment, is discussed elsewhere. This paper is concerned with the development of the active system, which simulates the regulatory responses of shivering, sweating, and peripheral vasomotion of unacclimatised subjects. Following a comprehensive literature review, 26 independent experiments were selected that were designed to provoke each of these responses in different circumstances. Regression analysis revealed that skin and head core temperature affect regulatory responses in a non-linear fashion. A further signal, i.e. the rate of change of the mean skin temperature weighted by the skin temperature error signal, was identified as governing the dynamics of thermoregulatory processes in the cold. Verification and validation work was carried out using experimental data obtained from 90 exposures covering a range of steady and transient ambient temperatures between 5įC and 50įC and exercise intensities between 46 W/m2 and 600 W/m2. Good general agreement with measured data was obtained for regulatory responses, internal temperatures, and the mean and local skin temperatures of unacclimatised humans for the whole spectrum of climatic conditions and for different activity levels.
Fiala, D.; Lomas, K. J.; Stohrer, M.
Changes in erosional input and environmental conditions at Lake Gerzensee, Switzerland, during Termination 1
NASA Astrophysics Data System (ADS)
The lateglacial record from Lake Gerzensee became an iconic figure since the early days of correlating terrestrial records with the results of polar ice core studies as initiated by Siegenthaler, Eicher, Oeschger and Dansgaard in 1984. Recently, the stable isotope record of Gerzensee was refined using a new sediment core retrieved in autumn 2008 in unprecedented resolution of 0.5cm (= 8-14 years). Depending on the sedimentation rate, the inferred temporal sample resolution of this new stable isotope record is between 8 and 14 years. A robust chronology was established through wiggle matching of the ?18O records from Gerzensee and NGRIP. Primary tie points between the two records were the prominent ?18O-shifts at the beginning and end of the BÝlling/AllerÝd (B/A) and the Younger Dryas (YD). Then, three minor oscillations (Gerzensee, GI-1c2, and Aegelsee Oscillation) clearly visible in both, the NGRIP and Gerzensee ?18O record, were correlated. XRF core scanning was then applied to the sediments of Lake Gerzensee to establish high-resolution elemental records with a spatial resolution of 2mm. These elemental concentrations allow studying the influence of the lateglacial climate pattern on the environment and the lake system in great detail. It can be observed that environmental thresholds such as vegetation density play a mayor role on the erosive input into a lake system. Detrital elements (like Al, K, Zr, Rb, and Ti) reflect the erosional influx, which strongly decreases during the BÝlling/AllerÝd reaching lowest concentration at the onset of the GI-1c2 oscillation. This coincides precisely with the full development of a stable pine forest in the vicinity of Lake Gerzensee demonstrating the strong coupling between vegetation and erosion. A comparable study (Lauterbach et al., 2011) at Mondsee, Austria allows to compare the same linkages between erosive input and pine forest development and to elaborate regional differences in this coupling. Initiated by technical developments, the transition in and out of the Younger Dryas received lately much attention in order to determine rates of change for the different proxies. Similar patterns and timing are observed between the Gerzensee elemental record and the sub-annually resolved NGRIP ice core record (Steffensen et al., 2008). For example, the detrial input at Gerzensee during the onset of the YD mimics in great detail the Ca2+ curve in Greenland pointing towards a fast change in the atmospheric circulation at this time. Beside the large lateglacial transitions, the short-term oscillation during the BÝlling/AllerÝd reveal unique patterns in the lake record. The strongest expressed cold swing in the elemental records of Lake Gerzensee is the Aegelsee Oscillation (GI-1d). Interestingly, the detrital input increases approximately 50 years earlier then the sharp decrease in the oxygen isotope at the onset of this oscillation. In order to evaluate if these patterns are site-specific or of larger spatial extent, more highly resolved records are needed from terrestrial archives, as well as from the ice sheets.
van Raden, U. J.; Gilli, A.; van Leeuwen, J.; Ammann, B.
Establishing Baseline environmental Conditions for the Proposed Yucca Mountain Repository, Nevada, U.S.A.
Research is underway to develop baseline site conditions and design monitoring programs for assurance to offsite residents and for performance confirmation for the proposed Yucca Mountain (YM) high-level waste repository in Nevada. This includes evaluation of existing and potential impacts on the proposed ''land withdrawal'' for the repository. A significant portion of the proposed land withdrawal includes areas now managed as part of the Nevada Test Site (NTS), and there is both contamination and land disturbance associated with past NTS activities. Establishing baseline conditions for the land withdrawal is important to distinguish potential impacts from repository operations from those resulting from previous activities, including some that took place from activities outside the land withdrawal. Among existing contamination is mixed fission products associated with the Nuclear Rocket Testing Program on the NTS in the 1960s. Some of these sites are being remediated as part of a federal facility agreement between the U.S. Department of Energy and the State of Nevada. However, even where radionuclides exist at levels below regulatory concern, characterizing them may be desirable if they are above background. In addition, Forty Mile Wash, the major drainage on the east side of YM, may be transporting radionuclides created from Plowshare project nuclear cratering experiments on Buckboard Mesa on the NTS. Although contaminant levels are not anticipated to present a risk, the point at which Forty Mile Wash leaves the proposed land withdrawal would be the closest point for an offsite receptor to YM. In addition, there is existing land disturbance (not necessarily associated with contamination) on both the NTS, as well as the portions of the proposed land withdrawal currently managed by the U.S. Bureau of Land Management and the U.S. Air Force. To establish a land disturbance baseline, high resolution multispectral satellite imagery collected in 2004 as well as hyperspectral imagery is being analyzed. Spectral and textural classification algorithms are being used to separate disturbed features such as paths, jeep trails, and building structures from background features. Disturbance features will be incorporated into a geographic information system. Follow-on activities will include examining areas of disturbance on the ground to characterize them and determine their origin. A longer term issue is the potential for radionuclide transport in groundwater from past areas of underground nuclear testing on the NTS (particularly Pahute Mesa) to areas where releases from YM could occur. To better address this, groundwater advective pathways are being traced from the proposed repository environment toward upgradient areas on the NTS. The Death Valley Regional Flow System model (issued in 2004 by the U.S. Geological Survey), which incorporates both YM and the NTS, is being used as the framework for the modeling. It is further enhanced with information from the YM Site Scale model and YM- and NTS-defined hydrogeologic units. Simulated pathways that intersect nuclear testing areas will identify regions on the NTS where potentially contaminated groundwater may originate and the routes for its potential migration toward YM.
D.S. Shafer; K.F. Pohlmann; C.E. Russell; D. Hovey-Spencer; M. Ye
Impact of Environmental Conditions on the Form and Function of Candida albicans Biofilms
Candida albicans, like other pathogens, can form complex biofilms on a variety of substrates. However, as the number of studies of gene regulation, architecture, and pathogenic traits of C. albicans biofilms has increased, so have differences in results. This suggests that depending upon the conditions employed, biofilms may vary widely, thus hampering attempts at a uniform description. Gene expression studies suggest that this may be the case. To explore this hypothesis further, we compared the architectures and traits of biofilms formed in RPMI 1640 and Spider media at 37įC in air. Biofilms formed by a/? cells in the two media differed to various degrees in cellular architecture, matrix deposition, penetrability by leukocytes, fluconazole susceptibility, and the facilitation of mating. Similar comparisons of a/a cells in the two media, however, were made difficult given that in air, although a/a cells form traditional biofilms in RPMI medium, they form polylayers composed primarily of yeast cells in Spider medium. These polylayers lack an upper hyphal/matrix region, are readily penetrated by leukocytes, are highly fluconazole susceptible, and do not facilitate mating. If, however, air is replaced with 20% CO2, a/a cells make a biofilm in Spider medium similar architecturally to that of a/? cells, which facilitates mating. A second, more cursory comparison is made between the disparate cellular architectures of a/a biofilms formed in air in RPMI and Lee's media. The results demonstrate that C. albicans forms very different types of biofilms depending upon the composition of the medium, level of CO2 in the atmosphere, and configuration of the MTL locus.
Daniels, Karla J.; Park, Yang-Nim; Srikantha, Thyagarajan; Pujol, Claude
Impact of environmental conditions on the form and function of Candida albicans biofilms.
Candida albicans, like other pathogens, can form complex biofilms on a variety of substrates. However, as the number of studies of gene regulation, architecture, and pathogenic traits of C. albicans biofilms has increased, so have differences in results. This suggests that depending upon the conditions employed, biofilms may vary widely, thus hampering attempts at a uniform description. Gene expression studies suggest that this may be the case. To explore this hypothesis further, we compared the architectures and traits of biofilms formed in RPMI 1640 and Spider media at 37įC in air. Biofilms formed by a/? cells in the two media differed to various degrees in cellular architecture, matrix deposition, penetrability by leukocytes, fluconazole susceptibility, and the facilitation of mating. Similar comparisons of a/a cells in the two media, however, were made difficult given that in air, although a/a cells form traditional biofilms in RPMI medium, they form polylayers composed primarily of yeast cells in Spider medium. These polylayers lack an upper hyphal/matrix region, are readily penetrated by leukocytes, are highly fluconazole susceptible, and do not facilitate mating. If, however, air is replaced with 20% CO2, a/a cells make a biofilm in Spider medium similar architecturally to that of a/? cells, which facilitates mating. A second, more cursory comparison is made between the disparate cellular architectures of a/a biofilms formed in air in RPMI and Lee's media. The results demonstrate that C. albicans forms very different types of biofilms depending upon the composition of the medium, level of CO2 in the atmosphere, and configuration of the MTL locus. PMID:23954841
Daniels, Karla J; Park, Yang-Nim; Srikantha, Thyagarajan; Pujol, Claude; Soll, David R
Precision and accuracy of spectrophotometric pH measurements at environmental conditions in the Baltic Sea
NASA Astrophysics Data System (ADS)
The increasing uptake of anthropogenic CO2 by the oceans has raised an interest in precise and accurate pH measurement in order to assess the impact on the marine CO2-system. Spectrophotometric pH measurements were refined during the last decade yielding a precision and accuracy that cannot be achieved with the conventional potentiometric method. However, until now the method was only tested in oceanic systems with a relative stable and high salinity and a small pH range. This paper describes the first application of such a pH measurement system at conditions in the Baltic Sea which is characterized by a wide salinity and pH range. The performance of the spectrophotometric system at pH values as low as 7.0 (ďtotalĒ scale) and salinities between 0 and 35 was examined using TRIS-buffer solutions, certified reference materials, and tests of consistency with measurements of other parameters of the marine CO2 system. Using m-cresol purple as indicator dye and a spectrophotometric measurement system designed at Scripps Institution of Oceanography (B. Carter, A. Dickson), a precision better than Ī0.001 and an accuracy between Ī0.01 and Ī0.02 was achieved within the observed pH and salinity ranges in the Baltic Sea. The influence of the indicator dye on the pH of the sample was determined theoretically and is presented as a pH correction term for the different alkalinity regimes in the Baltic Sea. Because of the encouraging tests, the ease of operation and the fact that the measurements refer to the internationally accepted ďtotalĒ pH scale, it is recommended to use the spectrophotometric method also for pH monitoring and trend detection in the Baltic Sea.
Hammer, Karoline; Schneider, Bernd; Kuli?ski, Karol; Schulz-Bull, Detlef E.
Investigation of Techniques to Improve Continuous Air Monitors Under Conditions of High Dust Loading in Environmental Settings
A number of DOE facilities, such as the Los Alamos National Laboratory (LANL) and the Waste Isolation Pilot Plant (WIPP), use alpha-particle environmental continuous air monitors (ECAMs) to monitor air for unwanted releases of radioactive aerosols containing such materials as plutonium and uranium. High sensitivity, ease of operation, and lack of false alarms are all important for ECAMs. The object of the project was to conduct investigations to improve operation of ECAMs, particularly under conditions where a lot of nonradioactive dust may be deposited on the filters (conditions of high dust loading). The presence of such dust may increase the frequency with which filters must be changed and can lead to an increased incidence of false alarms due to deteriorated energy resolution and response specificity to the radionuclides of interest. A major finding of the investigation, not previously documented, was that under many conditions thick layers of underlying nonradioactive dust do not decrease energy resolution and specificity for target radionuclides if the radioactive aerosol arrives as a sudden thin burst deposit, as commonly occurs in the early-warning alarm mode. As a result, operators of ECAMs may not need to change filters as often as previously thought and have data upon which to base more reliable operating procedures.
Suilou Huang; Stephen D. Schery; John C. Rodgers
Physiology of Geobacter metallireducens under excess and limitation of electron donors. Part II. Mimicking environmental conditions during cultivation in retentostats.
The strict anaerobe Geobacter metallireducens was cultivated in retentostats under acetate and acetate plus benzoate limitation in the presence of Fe(III) citrate in order to investigate its physiology under close to natural conditions. Growth rates below 0.003h(-1) were achieved in the course of cultivation. A nano-liquid chromatography-tandem mass spectrometry-based proteomic approach (nano-LC-MS/MS) with subsequent label-free quantification was performed on proteins extracted from cells sampled at different time points during retentostat cultivation. Proteins detected at low (0.002h(-1)) and high (0.06h(-1)) growth rates were compared between corresponding growth conditions (acetate or acetate plus benzoate). Carbon limitation significantly increased the abundances of several catabolic proteins involved in the degradation of substrates not present in the medium (ethanol, butyrate, fatty acids, and aromatic compounds). Growth rate-specific physiology was reflected in the changed abundances of energy-, chemotaxis-, oxidative stress-, and transport-related proteins. Mimicking natural conditions by extremely slow bacterial growth allowed to show how G. metallireducens optimized its physiology in order to survive in its natural habitats, since it was prepared to consume several carbon sources simultaneously and to withstand various environmental stresses. PMID:24736031
Marozava, Sviatlana; RŲling, Wilfred F M; Seifert, Jana; KŁffner, Robert; von Bergen, Martin; Meckenstock, Rainer U
Higher Environmental Relative Moldiness Index Values Measured in Homes of Adults with Asthma, Rhinitis, or both Conditions
Higher values of the Environmental Relative Moldiness Index (ERMI), a DNA-based method for quantifying indoor molds, have been associated with asthma in children. In this study, settled dust samples were collected from the homes of adults with asthma, rhinitis, or both conditions (n=139 homes) in Northern California. The ERMI values for these samples were compared to those from dust collected in homes from the same geographic region randomly selected as part of the 2006 American Healthy Home Survey (n=44). The median ERMI value in homes of adult with airway disease (6) was significantly greater than median ERMI value (2) in the randomly selected homes (p<0.0001). In this study in northern California, the homes of adults with asthma had ERMI values consistent with a heavier burden of indoor mold than that measured in other homes from the same region.
Blanc, Paul D.; Quinlan, Patricia J.; Katz, Patricia P.; Balmes, John R.; Trupin, Laura; Cisternas, Miriam G.; Wymer, Larry; Vesper, Stephen J.
Impact of environmental conditions on the contact physics of gold contact RF microelectromechanical systems (MEMS) switches
NASA Astrophysics Data System (ADS)
RF MEMS switch technology is poised to create a new generation of devices capable of vastly outperforming current mechanical and semiconductor switching technology. Despite the efforts of top industrial, academic, and government labs, commercialization of RF MEMS switches has lagged expectations. This dissertation focuses on issues associated with switch contact physics. Understanding the failure mechanisms for metal contact switches is a complex challenge. There is strong interplay between variables such as mechanical creep, deformation, contact heating, contact asperity size, real contact area, and current flow leading to the eventual failure of the switch. Stiction failures moreover are highly sensitive to ambient conditions and absorbed film layers at the switch contact. The experiments in this thesis seek to isolate individual failure mechanisms and tie them to the physics driving that behavior through correlation of experimental data and theoretical modeling. Four experiments in controlled environments were performed: (1) the impact of cryogenic temperatures on RF MEMS contacts, (2) a correlation between experimental data and theoretical modeling for gold asperity creep at room and cryogenic temperatures, (3) a power law relationship between contact resistance and time dependent creep, and (4) the pressure dependence of switch closure. Cryogenic temperatures were used to isolate contaminant film effects. Contaminant films were found to have less mobility at 77 K, and contact resistance measurements showed that the film could be reduced on the contact surface through mechanical cycling and high temperatures at the gold asperities. It was also noted at cryogenic temperatures that the choice of atmosphere was important. A nitrogen atmosphere at liquid nitrogen temperature produced variable contact resistance as the condensed liquid boiled off the switch contacts. Data was correlated with a single asperity creep model to show that change in contact resistance as a function of time is related to the creep of gold asperities at the contact interface. The change in contact resistance over time can be described by a power law relation derived from the single asperity creep model that takes into account the surface topography, material characteristics, and contributions from additional sources such as adsorbed film layers. Additionally, it was shown that the creep mechanism was temperature dependent and that creep was significantly decreased at cryogenic temperatures. A drop in pressure as a result from cryogenic temperatures was observed to create switch bounce at closure. This was explored in a set of room temperature experiments which established the onset of bounce at 60 Torr. The results were and correlated to the damping coefficient and the ratio of the damping force to the electrostatic force of actuation. This work contributes to the field of contact physics and MEMS switch technology by firmly establishing the role of creep in contact mechanics and quantifying its time and temperature dependent impact on contact resistance.
Brown, Christopher John
Deposition of Cryptosporidium parvum oocysts in porous media: a synthesis of attachment efficiencies measured under varying environmental conditions.
An extensive set of column experiments was performed with freshly harvested Cryptosporidium parvum oocysts to evaluate the effects of solution chemistry, surface coatings, interactions with other suspended particles, and pore fluid velocity on the fate and transport of this widely occurring waterborne pathogen in sandy porous media. We synthesized our data set with a comprehensive literature survey of similar experiments, to compute attachment (collision) efficiencies (?) used in colloid filtration theory (CFT) using three models for the single collector efficiency (?) across a wide range of experimental conditions. Most prior experiments have observed the transport of surface-treated, sterile C. parvum oocyst in porous media. Our column data confirm for freshly harvested oocysts that the presence of iron coatings on the sand medium and the presence of suspended illite clay drastically enhance oocyst deposition. Increasing ionic strength and decreasing pH also systematically enhance the attachment efficiency. Attachment efficiency decreases only at a very high ionic strength, most likely as a result of steric repulsion and possibly other changes in oocyst surface properties. Attachment efficiencies vary with fluid flow rate but without showing specific trends. We found that the computed attachment efficiency across all reported experiments could be reliably estimated using a regression model based on parameters related to ionic strength and pH. The regression model performed better with the Nelson-Ginn ? model and Tufenkji-Elimelech ? model than with the Rajagopalan-Tien ? model. When CFT is used in environmental assessments, the proposed regression model provides a practical estimator for attachment efficiencies of C. parvum oocyst deposition in porous media for a variety of environmental conditions unfavorable to attachment. PMID:22861686
Park, Yeonjeong; Atwill, E Robert; Hou, Lingling; Packman, Aaron I; Harter, Thomas
Adaptation strategies to seasonal changes in environmental conditions of a domesticated horse breed, the Shetland pony (Equus ferus caballus).
Recent results suggest that the wild ancestor of the horse, the Przewalski horse, exhibits signs of a hypometabolism. However, there are speculations that domestic animals lost the ability to reduce energy expenditure during food shortage and adverse environmental conditions. Therefore, we investigated physiological and behavioural strategies employed by a robust domesticated horse breed, the Shetland pony, over the course of a year under temperate conditions by measuring ambient temperature (T(a)), subcutaneous temperature (T(s)), locomotor activity (LA), lying time, resting heart rate, body mass and body condition score. Ten animals were kept on pasture in summer and in open stables in winter; further, in winter the animals were allocated into one control and one feed-restricted group of five animals each to simulate natural seasonal food shortage. The annual course of the mean daily T(s) of all horses showed distinct fluctuations from a mean of 35.6Ī0.5įC, with higher variations in summer than in winter. Diurnal amplitudes in T(s) were highest (P<0.001) in April (12.6įC) and lowest in January (4.0įC), with a nadir around dawn and a peak around mid-day. The feed-restricted group had a significantly lower daily T(s) compared with the control group on cold winter days, with T(a) values below 0įC. Mean annual heart rate and LA followed T(a) closely. Heart rate of the feed-restricted animals significantly decreased from a mean of 52.8Ī8.1 beats min(-1) in summer to 29Ī3.9 beats min(-1) in winter and differed from the control group (P<0.001). Mean daily LA was lowest at the end of winter (7000 activity impulses day(-1)) and highest in summer (25,000 activity impulses day(-1)). Our results show that Shetland ponies exhibit signs of a winter hypometabolism indicated by reduced heart rate and T(s). Thus, domesticated horses seem to have maintained the capacity for seasonal adaptation to environmental conditions by seasonal fluctuations in their metabolic rate. PMID:22399650
Brinkmann, Lea; Gerken, Martina; Riek, Alexander
Efficacy of a store-based environmental change intervention compared with a delayed treatment control condition on store customers' intake of fruits and vegetables
Objective The present store-based intervention was designed to promote sales of fruits and vegetables (F&V) to increase intake among store customers Ė specifically customers of tiendas, small-to-medium-sized Latino food stores. Design Four tiendas were randomized to a 2-month environmental change intervention or a delayed treatment control condition. Employees and managers were trained to promote F&V sales, including how to implement a food marketing campaign and installing store equipment to promote fresh fruits and vegetables. The primary outcome was self-reported daily intake of F&V among a convenience sample of customers (at least forty per store) collected at baseline prior to randomization and then 4 months later. In addition, changes in availability of F&V in the tiendas, using unobtrusive observational methods, provided evidence of intervention fidelity. Setting Tiendas in central North Carolina. Subjects Participants included 179 customers who were recent immigrants from Mexico and Central America. Results A group-by-time interaction approached significance on daily servings of F&V; intervention customers reported an increase in F&V intake over time and as a function of the intervention (P?0∑06). Unexpectedly, self-efficacy for consuming more fruits (P?0∑01) and more vegetables (P?0∑06) decreased. In our store-level analyses, a group-by-time interaction was observed for availability of fresh and canned vegetables; the intervention increased availability of vegetables but not fruit. Conclusions Environmental change strategies to promote healthy eating are needed given the rates of obesity and diabetes in the Latino population. A store-based intervention was moderately effective at increasing customersí reported F&V intake. Such strategies can have a public health impact on underserved populations.
Ayala, Guadalupe X; Baquero, Barbara; Laraia, Barbara A; Ji, Ming; Linnan, Laura
Lilium spp. pollen in China (Liliaceae): taxonomic and phylogenetic implications and pollen evolution related to environmental conditions.
Recent molecular and karyologic studies have significantly modified delimitation of Lilium. However, despite the importance of pollen evolution in the genus comprehensive studies with electron microscopy and evaluation of pollen evolution are lacking. Therefore, we studied pollen morphology in a sample of 65 individuals from 37 taxa covering all the sections distributed in the world, using scanning electron microscopy. Our collection of 49 individuals from 21 taxa covering all five sections in China was also included in the database. We found pollen tetrads in L. bakerianum. Based on present and previous studies, our results suggest that pollen from L. formosanum should be classified as a new type, Formosanum. Combined with morphological and molecular evidence, pollen sculpture patterns appear to reflect phylogenetic relationships and are useful for species or subsection delimitation. Based on a comprehensive survey and correlation with potential functional implications, we propose the following hypothesis: evolution of an exine sculpture shows pollen type trends from Martagon ? Callose ? Concolor ? Formosanum. The evolutionary trend regarding pollen sculpture and size could be related to selective pressure to adapt to environmental conditions. Pollen size and shape showed a significantly positive correlation with annual precipitation, and smaller pollen grains appear to adapt better in habitats with extreme conditions. Evolution trends in exine sculpture do not appear to be definitively correlated with pollen size and shape. PMID:24498208
Du, Yun-peng; Wei, Chi; Wang, Zhong-xuan; Li, Shuang; He, Heng-bin; Jia, Gui-xia
Identification of risk factors for sub-optimal housing conditions in Australian piggeries: Part 3. Environmental parameters.
Between autumn 1997 and autumn 1999, we measured ventilation rates (using a CO2 balance method), air temperatures, and relative humidity (using self-contained dataloggers with built-in sensors) in 160 pig housing facilities in Queensland, South Australia, Victoria, and Western Australia, in each case over a 60 h period. In some buildings, the internal air velocities above the animals were also recorded. While the monitoring instruments were being set up, a detailed questionnaire was used to collect data on major housing features and management factors. This information was statistically analyzed to quantify the effects of housing and management factors on the resulting environment conditions using a multifactorial analysis. The overall mean air temperature, relative humidity, internal air velocity, and ventilation rate were 20.3 degrees C, 58.9%, 0.12 m s(-1), and 663.9 m3 h(-1) 500 kg(-1) live weight, respectively, across all buildings. Internal building temperature and humidity were affected statistically by the type of insulation material used, the classification of buildings, and external climatic conditions. Ventilation rates were primarily affected by the type of ventilation system used, height (size) of ventilation openings, stocking density (kg m(-3)), and length, width, and height of buildings. These findings should aid the development of strategies for the industry to improve environmental control in piggery buildings. PMID:18376534
Banhazi, T M; Seedorf, J; Rutley, D L; Pitchford, W S
Lilium spp. pollen in China (Liliaceae): Taxonomic and Phylogenetic Implications and Pollen Evolution Related to Environmental Conditions
Recent molecular and karyologic studies have significantly modified delimitation of Lilium. However, despite the importance of pollen evolution in the genus comprehensive studies with electron microscopy and evaluation of pollen evolution are lacking. Therefore, we studied pollen morphology in a sample of 65 individuals from 37 taxa covering all the sections distributed in the world, using scanning electron microscopy. Our collection of 49 individuals from 21 taxa covering all five sections in China was also included in the database. We found pollen tetrads in L. bakerianum. Based on present and previous studies, our results suggest that pollen from L. formosanum should be classified as a new type, Formosanum. Combined with morphological and molecular evidence, pollen sculpture patterns appear to reflect phylogenetic relationships and are useful for species or subsection delimitation. Based on a comprehensive survey and correlation with potential functional implications, we propose the following hypothesis: evolution of an exine sculpture shows pollen type trends from Martagon ? Callose ? Concolor ? Formosanum. The evolutionary trend regarding pollen sculpture and size could be related to selective pressure to adapt to environmental conditions. Pollen size and shape showed a significantly positive correlation with annual precipitation, and smaller pollen grains appear to adapt better in habitats with extreme conditions. Evolution trends in exine sculpture do not appear to be definitively correlated with pollen size and shape.
Du, Yun-peng; Wei, Chi; Wang, Zhong-xuan; Li, Shuang; He, Heng-bin; Jia, Gui-xia
Exploring Chemical Variables in Ligustrum lucidum Ait. F. Tricolor (Rehd.) Rehd. in Relation to Air Pollutants and Environmental Conditions
/ A diagnostic study was done on Ligustrum lucidum Ait. f. tricolor (Rehd.) Rehd. in relation to atmospheric pollutants in Cordoba city, Argentina. The study area receives regional pollutants and was categorized taking into account traffic level, industrial density, type of industry, location of the sample point in relation to the street corner, treeless condition, and topographic level. Dried weight/fresh weight ratio (DW/FW) and specific leaf area (SLA) were calculated, and concentrations of chlorophylls, carotenoids, total sulfur, soluble proteins, malondialdehyde (MDA), and hydroperoxy conjugated dienes (HPCD) were determined in leaf samples. Sulfur content correlates positively with traffic density and SLA correlates negatively with some combinations of the categorical variables; MDA correlates positively with topographic level and total protein concentration correlates negatively with treeless condition. On the basis of our results, traffic, location of trees, type of industry, situation of a tree with respect to others, and topographic level are the environmental variables to bear in mind when selecting analogous sampling points in a passive monitoring program. An approximation to predict tree injury may be obtained by measuring DW/FW ratio, proteins, pigments, HPCD, and MDA as they are responsible for the major variability of data.KEY WORDS: L. lucidum Ait. f. tricolor (Rehd.) Rehd.; Air pollution; Sulfur accumulation; Pigments; Urban environment; Argentina PMID:9236292
Pignata; Canas; Carreras; Orellana
Stable isotope signatures and element stoichiometry of Fucus vesiculosus as indicators for environmental conditions in the Kiel Bight, Baltic Sea
NASA Astrophysics Data System (ADS)
In the frame of the BMBF project BIOACID II we aim for an understanding of the natural distribution and variation of isotopic composition and C-N-S stoichiometry in Fucus vesiculosus growing around the coast line of the Kiel fjord (part of the Kiel bight). Environmental conditions (aquatic chemistry, temperature, salinity) were monitored, too. Some changes in aquatic chemistry are related to stress factors like human activity (e.g., waste input) and further factors leading to specific changes in the composition of Fucus vesiculosus. Sampling was carried out at different stations at the west and east coast of the Kiel Fjord. For each sampling station the aquatic chemistry (TA, pH, salinity, d13C(DIC), main and trace elements and nutrients) as well as the composition of the Fucus organic tissues (stoichiometry and stable isotope composition of carbon, nitrogen) are analysed. The Fucus tissue was sampled in three size classes (small, medium, large). It is shown, that Fucus vesiculosus indicates clear differences in the N contents and stable isotopes between the west and the east site of the Kiel Fjord. Stable nitrogen isotope signatures in Fucus vesiculosus, are useful proxies to identify the influence factors in the Fucus habitat. From the data it is obtained that the influence of human activity (wastewater treatment plant, harbour), small stream and drainage channels, which flow from the near coastal area into the bight, leads to different Fucus vesiculosus compositions. In future work, it is intended to extend the investigation to trace element signatures to further estimate environmental impacts.
Winde, Vera; Mahler, Annika; Voss, Maren; BŲttcher, Michael E.
Effects of Varying Environmental Conditions on Biological Control of Fusarium Wilt of Tomato by Nonpathogenic Fusarium spp.
ABSTRACT The influence of varying environmental and cropping conditions including temperature, light, soil type, pathogen isolate and race, and cultivar of tomato on biological control of Fusarium wilt of tomato by isolates of nonpathogenic Fusarium oxysporum (CS-20 and CS-24) and F. solani (CS-1) was evaluated in greenhouse and growth chamber experiments. Liquid spore suspensions (10(6)/ml) of the biocontrol isolates were applied to soilless potting mix at the time of tomato seeding, and the seedlings were transplanted into pathogen-infested field soil 2 weeks later. Temperature regimes ranging from 22 to 32 degrees C significantly affected disease development and plant physiological parameters. Biocontrol isolate CS-20 significantly reduced disease at all temperature regimes tested, yielding reductions of disease incidence of 59 to 100% relative to pathogen control treatments. Isolates CS-24 and CS-1 reduced disease incidence in the greenhouse and at high temperatures, but were less effective at the optimum temperature for disease development (27 degrees C). Growing plants under shade (50% of full light) versus full light affected some plant growth parameters, but did not affect the efficacy of biocontrol of any of the three bio-control isolates. Isolate CS-20 effectively reduced disease incidence (56 to 79% reduction) in four different field soils varying in texture (sandy to clayey) and organic matter content (0 to 3.2%). Isolate CS-1 reduced disease in the sandy and loamy soils (49 to 66% reduction), but was not effective in a heavy clay soil. Both CS-1 and CS-20 were equally effective against all three races of the pathogen, as well as multiple isolates of each race (48 to 66% reduction in disease incidence). Both isolates, CS-1 and CS-20, were equally effective in reducing disease incidence (66 to 80% reduction) by pathogenic races 1, 2, and 3 on eight different tomato cultivars containing varying levels of inherent resistance to Fusarium wilt (susceptible, resistant to race 1, or resistant to races 1 and 2). These results demonstrate that both these Fusarium isolates, and particularly CS-20, can effectively reduce Fusarium wilt disease of tomato under a variety of environmental conditions and have potential for further development. PMID:18944240
Larkin, Robert P; Fravel, Deborah R
Characterization of a novel carbonic anhydrase from freshwater pearl mussel Hyriopsis cumingii and the expression profile of its transcript in response to environmental conditions.
Gene encoding for ?-carbonic anhydrases (?-CAs) and their functions in fundamental metabolism and biomineralization are widely identified in mollusks. However, the transcriptional regulation of ?-CA genes in response to various environmental conditions remains unknown. In the present study, we characterized a cDNA encoding for an ?-CA (HcCA) from the freshwater pearl mussel Hyriopsis cumingii. The spatial and temporal expression patterns of HcCA indicate that this gene is mainly expressed in the mantle of juvenile mussels. The expression profile of HcCA under various environmental conditions reveals that the transcription of HcCA is significantly regulated by Ca(2+) concentration, water temperature, pH and air exposure. Our results suggest that HcCA is a crucial target gene by which the external environmental conditions affecting shell growth and pH homeostasis of H. cumingii. PMID:24853200
Ren, Gang; Wang, Yan; Qin, Jianguang; Tang, Jinyu; Zheng, Xiafei; Li, Youming
Influence of environmental factors on dissolved nitrate stable isotopes under denitrifying conditions - carbon sources and water isotopes
NASA Astrophysics Data System (ADS)
Stable isotopes in dissolved nitrate are regularly used to identify sources of nitrate contamination in aquifers and water bodies. A dual isotope plot of 15N and 18O in nitrate can provide good evidence of the origin of such pollution as various sources have different isotopic signatures. Microbial denitrification changes both isotopic values by removing nitrate with lighter isotopes first, thereby increasing ?18O as well as ?15N. This change can distort the determination of sources but also has the potential to be used to identify and quantify microbial denitrification. Previous studies found a wide range of enrichment factors (?) that did not allow conclusions towards the extent of microbial denitrification. However, it was found that during denitrification at each respective field site or laboratory experiment, there was a constant ratio in increase of the values of ?18O in relation to ?15N. That ratio was, however, not constant across field sites and the values published range from below 0.5 to more than 1.0. The reasons for these variations in enrichment factors and relative enrichment of oxygen compared to nitrogen are yet unknown. We conducted microcosm experiments with three different bacterial species to elucidate possible influences of environmental factors on these parameters. As a result we conclude that the type of carbon source available to denitrifying bacteria can play a role in the value of the enrichment factors, but not in the relative enrichment of the two isotopes. Specifically we found that complex hydrocarbons (toluene, benzoate) produce significantly different enrichment factors in nitrate than a simple hydrocarbon substrate (acetate). The relative enrichment of ?18O compared to ?15N was 0.86. We hypothesise that this influence is based on a variation in process kinetics of cross-membrane nitrate transport in relation to intracellular nitrate reduction. The core of the hypothesis is that nitrate transport into the cell becomes rate limiting as a result of a carbon source induced change in cell membrane composition. The apparent kinetic isotope effect observed outside the cell is then changed as transport-related isotope effects dominate the observations. In addition, a possible effect of water ?18O values on the ?18O of dissolved nitrate was researched. Intermediary nitrite is known to exchange oxygen atoms with water; a reverse reaction of the nitrate reducing step could thus influence the oxygen isotope composition of dissolved nitrate without changing the nitrogen isotopic composition in the same way. Such a process was already shown for sulfate reduction. By adding 18O-labelled water to microcosm experiments, we could show that such an exchange exists for selected microorganisms. The environmental implications of this result is discussed.
Wunderlich, A.; Meckenstock, R.; Einsiedl, F.
Conclusive quantum steering with superconducting transition-edge sensors
NASA Astrophysics Data System (ADS)
Quantum steering allows two parties to verify shared entanglement even if one measurement device is untrusted. A conclusive demonstration of steering through the violation of a steering inequality is of considerable fundamental interest and opens up applications in quantum communication. To date, all experimental tests with single-photon states have relied on post selection, allowing untrusted devices to cheat by hiding unfavourable events in losses. Here we close this 'detection loophole' by combining a highly efficient source of entangled photon pairs with superconducting transition-edge sensors. We achieve an unprecedented ~62% conditional detection efficiency of entangled photons and violate a steering inequality with the minimal number of measurement settings by 48 s.d.s. Our results provide a clear path to practical applications of steering and to a photonic loophole-free Bell test.
Smith, Devin H.; Gillett, Geoff; de Almeida, Marcelo P.; Branciard, Cyril; Fedrizzi, Alessandro; Weinhold, Till J.; Lita, Adriana; Calkins, Brice; Gerrits, Thomas; Wiseman, Howard M.; Nam, Sae Woo; White, Andrew G.
Conclusive quantum steering with superconducting transition edge sensors
NASA Astrophysics Data System (ADS)
Quantum steering allows two parties to verify shared entanglement even if one measurement device is untrusted. A conclusive demonstration of steering through the violation of a steering inequality is of considerable fundamental interest and opens up applications in quantum communication. To date all experimental tests with single photon states have relied on post-selection, allowing untrusted devices to cheat by hiding unfavorable events in losses. Here we close this ``detection loophole'' by combining a highly efficient source of entangled photon pairs with superconducting transition edge sensors. We achieve an unprecedented ė62% conditional detection efficiency of entangled photons and violate a steering inequality with the minimal number of measurement settings by 48 standard deviations. Our results provide a clear path to practical applications of steering and to a photonic loophole-free Bell test.
de Almeida, Marcelo P.; Smith, Devin H.; Gillett, Geo; Branciard, Cyril; Fedrizzi, Alessandro; Weinhold, Till J.; Lita, Adriana; Calkins, Brice; Gertis, Thomas; Nam, Sae Woo; White, Andrew G.
Conclusive quantum steering with superconducting transition-edge sensors
Quantum steering allows two parties to verify shared entanglement even if one measurement device is untrusted. A conclusive demonstration of steering through the violation of a steering inequality is of considerable fundamental interest and opens up applications in quantum communication. To date, all experimental tests with single-photon states have relied on post selection, allowing untrusted devices to cheat by hiding unfavourable events in losses. Here we close this 'detection loophole' by combining a highly efficient source of entangled photon pairs with superconducting transition-edge sensors. We achieve an unprecedented ?62% conditional detection efficiency of entangled photons and violate a steering inequality with the minimal number of measurement settings by 48 s.d.s. Our results provide a clear path to practical applications of steering and to a photonic loophole-free Bell test.
Smith, Devin H.; Gillett, Geoff; de Almeida, Marcelo P.; Branciard, Cyril; Fedrizzi, Alessandro; Weinhold, Till J.; Lita, Adriana; Calkins, Brice; Gerrits, Thomas; Wiseman, Howard M.; Nam, Sae Woo; White, Andrew G.
Difference in keratinase activity of dermatophytes at different environmental conditions is an attribute of adaptation to parasitism.
Dermatophytes are a group of morphologically and physiologically related moulds, which cause well-defined infection called dermatophytosis. The enzymatic ability of fungi to decompose keratin has long been interpreted as a key innovation in the evolution of animal dermatology. In the present study, keratinase activity profile among Trichophyton mentagrophytes, Trichophyton rubrum, Microsporum canis and Microsporum gypseum isolated on keratin substrates such as human hair, human nail and chicken feather at variable environmental conditions of temperature, pH and metal ions was elucidated. All the above-mentioned fungal strains were isolated from soil using To-KA-Va baiting technique and keratinolytic activity was measured spectrophotometrically. In the temperature range of 30-40 įC and slightly alkaline pH (7.0-8.0), Trichophyton produced the highest activity of keratinase. It can be presumed that high enzyme production of Trichophyton species at normal body temperature range and pH could be an attribute for obligate anthropization in some dermatophytes. PMID:22032519
Sharma, Anima; Chandra, Subhash; Sharma, Meenakshi
Molecular cloning and expression analysis of Pleurodeles waltl complement component C3 under normal physiological conditions and environmental stresses.
C3 is a component of the complement system that plays a central role in immunity, development and tissue regeneration. In this study, we isolated the C3 cDNA of the Iberian ribbed newt Pleurodeles waltl. This cDNA encodes a 1637 amino acid protein with an estimated molecular mass of 212.5kDa. The deduced amino acid sequence showed that P. waltl C3 contains all the conserved domains known to be critical for C3 function. Quantitative real-time PCR (qRT-PCR) demonstrated that under normal physiological conditions, P. waltl C3 mRNA is expressed early during development because it is likely required for neurulation. Then, its expression increased as the immune system developed. In adults, the liver is the richest source of C3, though other tissues can also contribute. Further analysis of C3 expression demonstrated that C3 transcription increased when P. waltl larvae were exposed to pH or temperature stress, suggesting that environmental modifications might affect this animal's defenses against pathogens. PMID:24768999
Guťguinou, Nathan; Huin-Schohn, Cťcile; Ouzren-Zarhloul, Nassima; Ghislin, Stťphanie; Frippiat, Jean-Pol
Genetic diversity of root nodulating bacteria associated with Retama sphaerocarpa in sites with different soil and environmental conditions.
The genetic diversity of root nodulating bacteria isolated from Retama sphaerocarpa was studied using BOX-A1R PCR and phylogenetic analysis of the 16S rRNA region, as well as the housekeeping genes atpD, glnII and recA. A total of 193 isolates were obtained from eight different sites with different soil and environmental conditions in the Iberian Peninsula. These isolates corresponded to 31 different strains that successfully nodulated R. sphaerocarpa seedlings in reinoculation trials. About one-third of the strains clustered with B. canariense or B. cytisi within Bradyrhizobium group I. The remaining strains clustered with B. elkanii/B. pachyrhizi within Bradyrhizobium group II or in separate clades that could represent new lineages. Based on the 16S rRNA and combined atpD+glnII+recA sequences, two to three lineages of root nodulating bacteria were found at each sampling site, except for Collado Garcia where five species were detected. B. canariense and B. elkanii/B. pachyrhizi were the most abundant species, whereas the least abundant were those related to B. retamae and a putative new lineage. B. canariense was found only in soils with neutral and acid pH, whereas B. retamae was the dominant species in alkaline soils. PMID:24461714
RodrŪguez-EcheverrŪa, Susana; Moreno, Silvia; Bedmar, Eulogio J
Listeria monocytogenes Scott A: cell surface charge, hydrophobicity, and electron donor and acceptor characteristics under different environmental growth conditions.
We determined the variations in the surface physicochemical properties of Listeria monocytogenes Scott A cells that occurred under various environmental conditions. The surface charges, the hydrophobicities, and the electron donor and acceptor characteristics of L. monocytogenes Scott A cells were compared after the organism was grown in different growth media and at different temperatures; to do this, we used microelectrophoresis and the microbial adhesion to solvents method. Supplementing the growth media with glucose or lactic acid affected the electrical, hydrophobic, and electron donor and acceptor properties of the cells, whereas the growth temperature (37, 20, 15, or 8 degrees C) primarily affected the electrical and electron donor and acceptor properties. The nonlinear effects of the growth temperature on the physicochemical properties of the cells were similar for cells cultivated in two different growth media, but bacteria cultivated in Trypticase soy broth supplemented with 6 g of yeast extract per liter (TSYE) were slightly more hydrophobic than cells cultivated in brain heart infusion medium (P < 0.05). Adhesion experiments conducted with L. monocytogenes Scott A cells cultivated in TSYE at 37, 20, 15, and 8 degrees C and then suspended in a sodium chloride solution (1.5 x 10(-1) or 1.5 x 10(-3) M NaCl) confirmed that the cell surface charge and the electron donor and acceptor properties of the cells had an influence on their attachment to stainless steel. PMID:10583984
Briandet, R; Meylheuc, T; Maher, C; Bellon-Fontaine, M N
Listeria monocytogenes Scott A: Cell Surface Charge, Hydrophobicity, and Electron Donor and Acceptor Characteristics under Different Environmental Growth Conditions
We determined the variations in the surface physicochemical properties of Listeria monocytogenes Scott A cells that occurred under various environmental conditions. The surface charges, the hydrophobicities, and the electron donor and acceptor characteristics of L. monocytogenes Scott A cells were compared after the organism was grown in different growth media and at different temperatures; to do this, we used microelectrophoresis and the microbial adhesion to solvents method. Supplementing the growth media with glucose or lactic acid affected the electrical, hydrophobic, and electron donor and acceptor properties of the cells, whereas the growth temperature (37, 20, 15, or 8įC) primarily affected the electrical and electron donor and acceptor properties. The nonlinear effects of the growth temperature on the physicochemical properties of the cells were similar for cells cultivated in two different growth media, but bacteria cultivated in Trypticase soy broth supplemented with 6 g of yeast extract per liter (TSYE) were slightly more hydrophobic than cells cultivated in brain heart infusion medium (P < 0.05). Adhesion experiments conducted with L. monocytogenes Scott A cells cultivated in TSYE at 37, 20, 15, and 8įC and then suspended in a sodium chloride solution (1.5 ◊ 10?1 or 1.5 ◊ 10?3 M NaCl) confirmed that the cell surface charge and the electron donor and acceptor properties of the cells had an influence on their attachment to stainless steel.
Briandet, Romain; Meylheuc, Thierry; Maher, Catherine; Bellon-Fontaine, Marie Noelle
Conjugal Transfer of the Pathogenicity Island ROD21 in Salmonella enterica serovar Enteritidis Depends on Environmental Conditions
Unstable pathogenicity islands are chromosomal elements that can be transferred from one bacterium to another. Salmonella enterica serovar Enteritidis (S. Enteritidis) is a pathogenic bacterium containing such unstable pathogenicity islands. One of them, denominated ROD21, is 26.5 kb in size and capable of excising from the chromosome in certain culture conditions, as well as during bacterial infection of phagocytic cells. In this study we have evaluated whether ROD21 can be effectively transferred from one bacterium to another. We generated a donor and several recipient strains of S. Enteritidis to carry out transfer assays in liquid LB medium. These assays showed that ROD21 is effectively transferred from donor to recipient strains of S. Enteritidis and S. Typhimurium. When Escherichia coli was used as the recipient strain, ROD21 transfer failed to be observed. Subsequently, we showed that a conjugative process was required for the transfer of the island and that changes in temperature and pH increased the transfer frequency between Salmonella strains. Our data indicate that ROD21 is an unstable pathogenicity island that can be transferred by conjugation in a species-specific manner between Salmonellae. Further, ROD21 transfer frequency increases in response to environmental changes, such as pH and temperature.
Salazar-Echegarai, Francisco J.; Tobar, Hugo E.; Nieto, Pamela A.; Riedel, Claudia A.; Bueno, Susan M.
A cyclin-dependent kinase family member (PHOA) is required to link developmental fate to environmental conditions in Aspergillus nidulans.
We addressed the question of whether Aspergillus nidulans has more than one cyclin-dependent kinase gene and identified such a gene, phoA, encoding two PSTAIRE-containing kinases (PHOAM1 and PHOAM47) that probably result from alternative pre-mRNA splicing. PHOAM47 is 66% identical to Saccharomyces cerevisiae Pho85. The function of this gene was studied using phoA null mutants. It functions in a developmental response to phosphorus-limited growth but has no effect on the regulation of enzymes involved in phosphorus acquisition. Aspergillus nidulans shows both asexual and sexual reproduction involving temporal elaboration of different specific cell types. We demonstrate that developmental decisions in confluent cultures depend upon both the initial phosphorus concentration and the inoculation density and that these factors influence development through phoA. In the most impressive cases, absence of phoA resulted in a switch from asexual to sexual development (at pH 8), or the absence of development altogether (at pH 6). The phenotype of phoA deletion strains appears to be specific for phosphorus limitation. We propose that PHOA functions to help integrate environmental signals with developmental decisions to allow ordered differentiation of specific cell types in A.nidulans under varying growth conditions. The results implicate a putative cyclin-dependent kinase in the control of development.
Bussink, H J; Osmani, S A
Timing, Frequency and Environmental Conditions Associated with Mainstem-Tributary Movement by a Lowland River Fish, Golden Perch (Macquaria ambigua)
Tributary and mainstem connections represent important links for the movement of fish and other biota throughout river networks. We investigated the timing, frequency and environmental conditions associated with movements by adult golden perch (Macquaria ambigua) between the mainstem of the mid-Murray River and a tributary, the Goulburn River, in south-eastern Australia, using acoustic telemetry over four years (2007Ė2011). Fish were tagged and released in autumn 2007Ė2009 in the mid-Murray (n?=?42) and lower Goulburn (n?=?37) rivers within 3Ė6 km of the mid-Murray-lower Goulburn junction. 38% of tagged fish undertook mainstemĖtributary movements, characterised mostly by temporary occupation followed by return of fish to the original capture river. Approximately 10% of tagged fish exhibited longer-term shifts between the mainstem and tributary. Movement of fish from the tributary into the mainstem occurred primarily during the spawning season and in some years coincided with the presence of golden perch eggs/larvae in drift samples in the mainstem. Many of the tributary-to-mainstem movements occurred during or soon after changes in flow. The movements of fish from the mainstem into the tributary were irregular and did not appear to be associated with spawning. The findings show that golden perch moved freely across the mainstemĖtributary interface. This demonstrates the need to consider the spatial, behavioural and demographic interdependencies of aquatic fauna across geographic management units such as rivers.
Koster, Wayne M.; Dawson, David R.; O'Mahony, Damien J.; Moloney, Paul D.; Crook, David A.
Timing, Frequency and Environmental Conditions Associated with Mainstem-Tributary Movement by a Lowland River Fish, Golden Perch (Macquaria ambigua).
Tributary and mainstem connections represent important links for the movement of fish and other biota throughout river networks. We investigated the timing, frequency and environmental conditions associated with movements by adult golden perch (Macquaria ambigua) between the mainstem of the mid-Murray River and a tributary, the Goulburn River, in south-eastern Australia, using acoustic telemetry over four years (2007-2011). Fish were tagged and released in autumn 2007-2009 in the mid-Murray (n?=?42) and lower Goulburn (n?=?37) rivers within 3-6 km of the mid-Murray-lower Goulburn junction. 38% of tagged fish undertook mainstem-tributary movements, characterised mostly by temporary occupation followed by return of fish to the original capture river. Approximately 10% of tagged fish exhibited longer-term shifts between the mainstem and tributary. Movement of fish from the tributary into the mainstem occurred primarily during the spawning season and in some years coincided with the presence of golden perch eggs/larvae in drift samples in the mainstem. Many of the tributary-to-mainstem movements occurred during or soon after changes in flow. The movements of fish from the mainstem into the tributary were irregular and did not appear to be associated with spawning. The findings show that golden perch moved freely across the mainstem-tributary interface. This demonstrates the need to consider the spatial, behavioural and demographic interdependencies of aquatic fauna across geographic management units such as rivers. PMID:24788137
Koster, Wayne M; Dawson, David R; O'Mahony, Damien J; Moloney, Paul D; Crook, David A
Cloud point extraction of plutonium in environmental matrixes coupled to ICPMS and ? spectrometry in highly acidic conditions.
A new cloud point extraction procedure has been developed for the quantification of plutonium(IV) in environmental samples. The separation procedure can be either coupled to inductively coupled plasma mass spectrometry (ICPMS) or ? spectrometry for plutonium quantification. The method uses a combination of selective ligand (P,P'-di(2-ethylhexyl) methanediphosphonic acid (H2DEH[MDP])) and micelle shielding by bromine formation to enable quantitative extraction of Pu in highly acidic solutions. Cross-optimization of all parameters (nonionic and ionic surfactant, chelating agent, bromate, bromide, and pH) led to optimal of the extraction conditions. Figures of merit of the method for the detection using ? spectrometry and ICPMS are reported (limit of detection, limit of quantification, minimal detectable activity, and recovery). Quantitative extractions (>95%) were obtained for a wide variety of aqueous and digested samples (synthetic urine, wastewater, drinking water, seawater, and soil samples). The method features the first successful coupling between ? spectrometry and cloud point extraction and is the first demonstration of CPE suitability with metaborate fusion as a sample preparation approach, techniques used extensively in nuclear industries. PMID:24074397
Labrecque, Charles; Whitty-Lťveillť, Laurence; LariviŤre, Dominic
Experimental Demonstration of the Formation of Liquid Brines under Martian Polar Conditions in the Michigan Mars Environmental Chamber
NASA Astrophysics Data System (ADS)
Liquid water is one of the necessary ingredients for the development of life as we know it. The behavior of various liquid states of H2O such as liquid brine, undercooled liquid interfacial water, subsurface melt water and ground water [1] needs to be understood in order to address the potential habitability of Mars for microbes and future human exploration. It has been shown thermodynamically that liquid brines can exist under Martian polar conditions [2, 3]. We have developed the Michigan Mars Environmental Chamber (MMEC) to simulate the entire range of Martian surface and shallow subsurface conditions with respect to temperature, pressure, relative humidity, solar radiation and soil wetness at equatorial and polar latitudes. Our experiments in the MMEC show that deliquescence of NaClO4, Mg(ClO4)2 and Ca(ClO4)2 occurs diurnally under the environmental conditions of the Phoenix landing site when these salts get in contact with water ice. Since Phoenix detected these salts and water ice at the landing site, including frost formation, it is extremely likely that deliquescence occurs at the Phoenix landing site. By layering NaClO4, Mg(ClO4)2 or Ca(ClO4)2 on top of a pure water ice slab at 800 Pa and 190 K and raising the temperature stepwise across the eutectic temperature of the perchlorate salts, we observe distinct changes in the Raman spectra of the samples when deliquescence occurs. When crossing the eutectic temperatures of NaClO4 (236 K), Mg(ClO4)2 (205 K) and Ca(ClO4)2 (199 K) [4, 5], the perchlorate band of the Raman spectrum shows a clear shift from 953 cm-1 to 936 cm-1. Furthermore, the appearance of a broad O-H vibrational stretching spectrum between 3244 cm-1 and 3580 cm-1 is another indicator of deliquescence. This process of deliquescence occurs on the order of seconds when the perchlorate salt is in contact with water ice. On the contrary, when the perchlorate salt is only subjected to water vapor in the Martian atmosphere, deliquescence was not observed within the Martian diurnal cycle. This greatly diminishes the possibility of liquid brine formation without water ice contact and has strong implications on future robotic and manned missions searching for liquid water on Mars. Acknowledgement: This research is supported by a grant from the NASA Astrobiology Program: Exobiology and Evolutionary Biology. Award #09-EXOB09-0050. References: [1] MartŪnez, G. M. and Renno, N. O. (2013), Water and Brines on Mars: Current Evidence and Implications for MSL, Space Sci. Rev., 175, 29-51. [2] Rennů, N. O., et al. (2009), Possible physical and thermodynamical evidence for liquid water at the Phoenix landing site, J. Geophys. Res., 114, E00E03. [3] Zorzano, M.-P., et al., Stability of liquid saline water on present day Mars, Geophys. Res. Lett., 36, L20201. [4] Hanley, J. et al. (2009), Low Temperature Aqueous Perchlorate Solutions on the Surface of Mars, Proceedings 40th Lunar and Planetary Sciences Conference, The Woodlands, TX, USA. [5] Marion, G. M. et al. (2010), Modeling Aqueous Perchlorate Chemistries with Applications to Mars, Icarus, 207, 675-685.
Fischer, Erik; Martinez, German; Elliott, Harvey; Borlina, Caue; Renno, Nilton
Palaeolithic use of fossil combustible linked to singular environmental conditions : the long term el Kowm record (Syria).
NASA Astrophysics Data System (ADS)
Identifying the adaptation of hunter-gatherer communities to particular situations that provided natural resources is a major concern for multidisciplinary team studying archaeological contexts. This challenge is illustrated in the desertic El Kowm basin in central Syria by data from Hummal and El Kowm Paleolithic sites. The sites form prominent mounds at artesian springs resulting from recurrent episodes of lacustrine, limnic and aeolian sedimentation in pseudo-karstic depressions. The few meter sequences provide semi-continuous succession of archaeological levels from the Oldest Palaeolithic (Oldowan) to the early Neolithic period. This long term continuity of occupation is partly due to attracting conditions due to the profusion of water from epithermal artesian wells during periods of high water recharge. In addition, we document here the unique potential of this endoreic basin to have accumulated singular fossil combustible of high energy value during particular environmental episodes. The latter are represented by the recurrence of distinctive black organogenic facies showing a contrasting micro stratification formed of interlayered grey calcareous silty clay, dark brown organic rich clay and dull orange clay. Spatial excavation has shown the unique preservation of Palaeolithic occupation surfaces in association to the microstratified facies. High resolution sampling and multi-proxy analysis have allowed explaining the formation of the microstratified facies from rapid changes of environmental conditions in response to contrasting fluctuations of atmospheric dust loading, precipitation events, rainwater quality and evapotranspiration. Organogenic microfacies formed at different time periods share common compositional assemblage and structural behaviour: occurrence of exotic fine sand-sized debris formed of metal-rich carbonaceous components with polymer, fine charcoal, vitrous carbon, carbon fibres, and exotic rock clasts with a metal-rich carbonaceous coating; highly stable microstructure and low wettability. Based on their analytical properties, the carbonaceous polymorphs and the associated mineral components are shown to deriving from fossil combustible of stratospheric origin. The comparison with modern analogues (cf. Courty et al., 2012) has provided keys to explaining the organogenic microfacies from accumulation episodes of exotic stratospheric aerosols in response to serial meteor explosion at high altitude. Geogenic markers and microfacies pattern show four situations: (1) nearly intact ancient surfaces with pulverized carbonaceous composite debris that trace the local effects of meteor explosion ; (2) secondary concentrations expressing accumulation of stratospheric aerosols from the heavy rainfall events subsequent to the meteor explosions; (3) relictual concentrations resulting from selective accumulation of the most resistant components by chemical and physical erosion along to the fossilization; (4) human-controlled concentrations of the unusual debris indicating intentional collect, use and transformation of the singular fossil combustible and related materials. Ancient humans are thus suggested to have regularly exploited the local sources of the singular fossil combustible that formed during episodes of serial cosmic explosions. The direct effect of increased atmospheric dust loading on precipitation regime explains the apparent synchrony between occupation phases and local climate changes. These are simply two distinctive responses to a common cause. Courty, BenoÓt and Vaillant (2012). Possible interaction of meteor explosion with stratospheric aerosols on cloud nucleation based on 2011 observations. Geophysical Research Abstracts Vol. 14, EGU2012.
Courty, M.-A.; Le Tensorer, J.-M.; BoŽda, E.; Muhesen, S.; Alsakhel, E.; WegmŁller, F.
Investigation on a method incorporating inhomogeneous environmental conditions into CFD analysis of outdoor thermal environment coupled with multifractional human thermoregulation model
In this paper, a new method that incorporates inhomogeneous environmental conditions into computational fluid dynamics (CFD) analysis coupled with multifractional human thermoregulation model has been described. This method can be used to investigate the distributions of absorbed solar and longwave radiations from around a human body in outdoor space; it is also used to evaluate the effects of airflow on
Shinji Yoshida; Masayuki Oguro
The Effect of Team Training Strategies on Team Mental Model Formation and Team Performance under Routine and Non-Routine Environmental Conditions
ERIC Educational Resources Information Center
The current study examined how the type of training a team receives (team coordination training vs. cross-training) influences the type of team mental model structures that form and how those mental models in turn impact team performance under different environmental condition (routine vs. non-routine). Three-hundred and fifty-two undergraduateÖ
Hamilton, Katherine L.
Impact of Environmental Conditions (pH, Ionic Strength, And Electrolyte Type) On The Surface Charge And Aggregation Of Silver Nanoparticles Suspensions
The impact of capping agents and environmental conditions (pH, ionic strength, and background electrolytes) on surface charge and aggregation potential of silver nanoparticles (AgNPs) suspensions were investigated. Capping agents are chemicals used in the synthesis of nanopartic...
Characterization of condenser microphones under different environmental conditions for accurate speed of sound measurements with acoustic resonators
NASA Astrophysics Data System (ADS)
Condenser microphones are more commonly used and have been extensively modeled and characterized in air at ambient temperature and static pressure. However, several applications of interest for metrology and physical acoustics require to use these transducers in significantly different environmental conditions. Particularly, the extremely accurate determination of the speed of sound in monoatomic gases, which is pursued for a determination of the Boltzmann constant k by an acoustic method, entails the use of condenser microphones mounted within a spherical cavity, over a wide range of static pressures, at the temperature of the triple point of water (273.16 K). To further increase the accuracy achievable in this application, the microphone frequency response and its acoustic input impedance need to be precisely determined over the same static pressure and temperature range. Few previous works examined the influence of static pressure, temperature, and gas composition on the microphone's sensitivity. In this work, the results of relative calibrations of 1/4 in. condenser microphones obtained using an electrostatic actuator technique are presented. The calibrations are performed in pure helium and argon gas at temperatures near 273 K and in the pressure range between 10 and 600 kPa. These experimental results are compared with the predictions of a realistic model available in the literature, finding a remarkable good agreement. The model provides an estimate of the acoustic impedance of 1/4 in. condenser microphones as a function of frequency and static pressure and is used to calculate the corresponding frequency perturbations induced on the normal modes of a spherical cavity when this is filled with helium or argon gas.
Guianvarc'h, Cťcile; Gavioso, Roberto M.; Benedetto, Giuliana; Pitre, Laurent; Bruneau, Michel
Characterization of condenser microphones under different environmental conditions for accurate speed of sound measurements with acoustic resonators.
Condenser microphones are more commonly used and have been extensively modeled and characterized in air at ambient temperature and static pressure. However, several applications of interest for metrology and physical acoustics require to use these transducers in significantly different environmental conditions. Particularly, the extremely accurate determination of the speed of sound in monoatomic gases, which is pursued for a determination of the Boltzmann constant k by an acoustic method, entails the use of condenser microphones mounted within a spherical cavity, over a wide range of static pressures, at the temperature of the triple point of water (273.16 K). To further increase the accuracy achievable in this application, the microphone frequency response and its acoustic input impedance need to be precisely determined over the same static pressure and temperature range. Few previous works examined the influence of static pressure, temperature, and gas composition on the microphone's sensitivity. In this work, the results of relative calibrations of 1/4 in. condenser microphones obtained using an electrostatic actuator technique are presented. The calibrations are performed in pure helium and argon gas at temperatures near 273 K and in the pressure range between 10 and 600 kPa. These experimental results are compared with the predictions of a realistic model available in the literature, finding a remarkable good agreement. The model provides an estimate of the acoustic impedance of 1/4 in. condenser microphones as a function of frequency and static pressure and is used to calculate the corresponding frequency perturbations induced on the normal modes of a spherical cavity when this is filled with helium or argon gas. PMID:19655971
Guianvarc'h, Cťcile; Gavioso, Roberto M; Benedetto, Giuliana; Pitre, Laurent; Bruneau, Michel
Plant community, primary productivity, and environmental conditions following wetland re-establishment in the Sacramento-San Joaquin Delta, California
Wetland restoration can mitigate aerobic decomposition of subsided organic soils, as well as re-establish conditions favorable for carbon storage. Rates of carbon storage result from the balance of inputs and losses, both of which are affected by wetland hydrology. We followed the effect of water depth (25 and 55 cm) on the plant community, primary production, and changes in two re-established wetlands in the Sacramento San-Joaquin River Delta, California for 9 years after flooding to determine how relatively small differences in water depth affect carbon storage rates over time. To estimate annual carbon inputs, plant species cover, standing above- and below-ground plant biomass, and annual biomass turnover rates were measured, and allometric biomass models for Schoenoplectus (Scirpus) acutus and Typha spp., the emergent marsh dominants, were developed. As the wetlands developed, environmental factors, including water temperature, depth, and pH were measured. Emergent marsh vegetation colonized the shallow wetland more rapidly than the deeper wetland. This is important to potential carbon storage because emergent marsh vegetation is more productive, and less labile, than submerged and floating vegetation. Primary production of emergent marsh vegetation ranged from 1.3 to 3.2 kg of carbon per square meter annually; and, mid-season standing live biomass represented about half of the annual primary production. Changes in species composition occurred in both submerged and emergent plant communities as the wetlands matured. Water depth, temperature, and pH were lower in areas with emergent marsh vegetation compared to submerged vegetation, all of which, in turn, can affect carbon cycling and storage rates. ?? Springer Science+Business Media B.V. 2009.
Miller, R. L.; Fujii, R.