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QRS complex duration enhancement as ventricular late potential indicator by signal-averaged ECG using time-amplitude alignments.
Avitia, Roberto L; Reyna, Marco A; Bravo-Zanoguera, Miguel E; Cetto, Lucio A
Ventricular late potentials (VLPs) are small-amplitude waves with a short duration that appear at the end part of the QRS complex, making a QRS complex duration larger. The signal-averaged electrocardiography (ECG) technique enhances VLPs and beats, assuming noise as the only random variable. However, ECG signals are not completely stationary and different elongations appear in both time and amplitude in each beat. This research proposes to use piecewise linear approximation to segment each beat and performs the alignment of the beats using the technique known as derivative dynamic time-warping to have beats better aligned and consequently enhance the presence of VLPs. We recorded high-resolution ECGs (HRECGs) from 50 subjects in supine position with no heart-stroke antecedents. VLPs were created synthetically and added to the HRECGs. Two cases were evaluated: (i) duration of the QRS complexes with VLPs without beats alignment, and (ii) duration of QRS complexes with VLPs using beats alignment in time and amplitude. Considering QRS duration as an indicative of VLP presence, results show that when using beats alignment in time and amplitude it is possible to reach a sensitivity of 0.96 and a specificity of 0.52, as opposed to 0.72 and 0.40, respectively, when using only averaging without beats alignment in time and amplitude. PMID:23446922
QRS complex duration and dipyridamole gated SPECT findings in the left bundle branch block
Sabahat Inanir; Billur Caliskan; Sena Tokay; Ahmet Oktay
ObjectiveĀĀThe aim of this study was to investigate the relationship between QRS duration, artifactual perfusion abnormalities, and left\\u000a ventricular function in patients with left bundle branch block (LBBB) using dipyridamole technetium-99m sestamibi electrocardiography-gated\\u000a single-photon emission computed tomography (SPECT).\\u000a \\u000a \\u000a \\u000a MethodsĀĀTwenty-three patients (62 ▒ 12.2 years, 18 women, 5 men) with complete LBBB were analyzed. All patients underwent rest-dipyridamole\\u000a gated SPECT (1-day
Effect of exercise on QRS duration in healthy men: a computer ECG analysis.
Goldberger, A L; Bhargava, V
Increased sympathetic tone with exercise enhances ventricular conduction and would be predicted to shorten QRS duration. Previous studies, however, have not consistently documented such changes. Using a digital electrocardiograph (ECG) cart sampling at 500 Hz, a bipolar precordial lead (V5-V2) was recorded (supine, at end expiration) in 25 healthy men (mean age 29 yr, range 19-37) at rest and immediately after submaximal treadmill exercise. QRS duration was measured on complexes recorded at high gain and expanded time scale. A significant (P less than 0.0005) decrease [4.9 +/- 2.3 (SD) ms] in QRS duration was noted, and decreased QRS duration was observed in all 25 subjects (range 1-10 ms). Furthermore there was significant (P less than 0.01) shortening of the intervals between QRS onset and Q-wave nadir (1.2 +/- 2.0 ms) and between QRS onset and R-wave peak (2.4 +/- 2.5 ms), as well as of the Q-R interval (1.3 +/- 2.7 ms). However, there were no significant differences in percent shortening of early vs. later phases of the QRS. To exclude digital sampling errors the same protocol was also applied in 11 healthy men by using an analog ECG cart. QRS duration immediately postexercise shortened by 7.1 +/- 4.3 ms (range 2-11.5 ms), which was not significantly different from the results obtained with the digital ECG. We conclude that decreased QRS duration is a physiological response to moderate treadmill exercise in healthy men, reflecting enhancement of conduction in early, middle, and later phases of ventricular activation. PMID:6853284
Relation of QRS duration to response to cardiac resynchronization therapy.
Sassone, Biagio; Gambetti, Simona; Bertini, Matteo; Beltrami, Matteo; Mascioli, GiosuĶ; Bressan, Sabrina; FucÓ, Giuseppe; Pacchioni, Federico; Pedaci, Mario; Michelotti, Federica; Bacchi Reggiani, Maria Letizia; Padeletti, Luigi
Left bundle branch block (LBBB) is the most reliable electrocardiographic predictor of responsiveness to cardiac resynchronization therapy (CRT). However, not all patients with LBBB will respond to CRT. Our aim was to investigate the interaction between QRS duration, LBBB-type morphology, and the responsiveness to CRT. We retrospectively analyzed electrocardiograms of 243 patients who underwent CRT implantation according to current clinical indications. A 6-month reduction of left ventricular end-systolic volume >15% was used to identify CRT responders. The clinical end point consisted of death, hospitalization for heart failure and sustained rapid ventricular tachyarrhythmias. An LBBB morphology was present in 169 patients (70%) and 101 of these (60%) were responders to CRT. Analyzing the interaction between QRS duration and CRT responsiveness in patients with LBBB, a "U shaped" distribution resulted, with nonresponders clustered between 120 and 130 ms and above 180 ms. The receiver operating characteristic curve analysis identified 178 ms as the optimal cut-off value of QRS to predict a nonresponsiveness to CRT (area under the curve = 0.67 [95% confidence interval 0.57 to 0.76]). At multivariate analysis, only an ischemic cause and a QRS ?178 ms were independent predictors of nonresponsiveness to CRT (area under the curve = 0.75). Patients with LBBB with QRS ?178 ms had greater likelihood of adverse clinical events during a mean follow-up of 32 months (p = 0.049). In conclusion, in patients with LBBB undergoing CRT, a marked QRS widening (i.e., ?178 ms) is related to worse echocardiographic responsiveness and lower event free survival rate compared with patients with an intermediate QRS widening. PMID:25465934
Relation of QRS duration to mortality in a community-based cohort with hypertrophic cardiomyopathy.
Bongioanni, Sergio; Bianchi, Francesca; Migliardi, Alessandro; Gnavi, Roberto; Pron, Paolo Giay; Casetta, Marzia; Conte, Maria Rosa
A prolonged QRS duration on the standard electrocardiogram is associated with an increased risk of cardiovascular death in cardiomyopathies of different origin. However, the relation between QRS duration and prognosis in hypertrophic cardiomyopathy (HC) remains undefined. We assessed the relation between QRS duration and cardiovascular death in 241 consecutive patients with HC. The study cohort was divided into 2 groups according to QRS duration: <120 and > or =120 ms. Of the 241 patients, 191 (79%) had a QRS duration <120 ms and 50 (21%) a QRS duration > or =120 ms. During a mean follow-up of 7.9 +/- 5.1 years, 35 patients died of cardiovascular causes related to HC. Of these 35 patients, 13 (6%) had a QRS duration <120 ms and 22 (43%) had a QRS duration > or =120 ms (p <0.01). Risk of cardiovascular death was significantly higher in patients with a QRS duration > or =120 ms than in those with a QRS duration <120 ms (relative risk 5.2, p <0.0001). At 8-year follow-up, cumulative risks of HC-related death were 7.1% in patients with a QRS duration <120 ms and 55% in those with a QRS duration > or =120 ms. Multivariate analysis confirmed that a QRS duration > or =120 ms was independently associated with an increased risk of cardiovascular death (hazard ratio 3.2, p = 0.007). New York Heart Association functional class III/IV was the only other clinical variable significantly and independently associated with an increased risk of cardiovascular death. In conclusion, in patients with HC, QRS duration on standard electrocardiogram is directly related to cardiovascular mortality, and a QRS duration > or =120 ms is a strong and independent predictor of prognosis. PMID:17659936
Khandaker Abul; Kalam Azad
Signal processing problems related to abdominal-lea d fetal ECG include the cancellation of the maternal QRS complex, signal enhancement of the fetal QRS complex and detection of the presence of a fetal R-wave to compute the fetal heart rate. This paper describes an improved scheme for detecting the presence of the QRS complexes from the enhanced fetal electrocardiograph (ECG) signal
The skinny on wide QRS complexes.
MacKenzie, Ross
The presence of widened QRS complexes in a life insurance applicant's electrocardiogram may be due to such things as an intraventricular conduction defect, preexcitation syndrome, left ventricular hypertrophy, ventricular pacing, hyperkalemia and a ventricular rhythm. Clinical information and basic electrocardiogram interpretation techniques can usually narrow the differential diagnosis. Risk assessment of intraventricular conduction defects requires identification of typical electrocardiographic patterns followed by a careful search for additional electrocardiographic features, which may indicate the presence of more extensive conducting system disease and/or coexisting disease affecting the myocardium. PMID:17500356
Interrelations between QRS morphology, duration, and HV interval changes following right bundle branch radiofrequency catheter ablation.
Mehdirad, A A; Curtiss, E; Tchou, P
Interrelations between QRS morphology, duration, and HV interval changes in a model of "complete" bundle branch block following right bundle branch radiofrequency ablation have not been subjected to systematic study. This article describes these interrelations in patients who underwent right bundle ablation. Over a period of 42 months, 16 patients underwent radiofrequency ablation of the right bundle for treatment of bundle branch reentrant tachycardia. All 16 patients had prolonged HV interval at baseline (minimum = 60 ms; mean = 68 +/- 8 ms). After ablation, one patient developed complete heart block; the remaining 15 patients developed complete right bundle branch block (RBBB) and further prolongation of the HV interval (increment = 24 +/- 16 ms). In 14 of these 15 patients, QRS duration was 138 +/- 26 ms before ablation and increased to 168 +/- 13 ms after ablation. In the remaining patient, the QRS duration was 160 ms before ablation and shortened to 144 ms following ablation despite further HV prolongation. Larger increases of HV interval after ablation were associated with smaller or negative changes in QRS duration (r = -0.77). Three was a direct relationship between QRS duration at baseline and the increment in HV interval after ablation (r = 0.70), and an inverse relationship between QRS duration before and after ablation (r = 0.84). Radiofrequency ablation of right bundle may be associated with an increase in HV interval and QRS duration. However, HV interval prolongation is not necessarily associated with QRS duration widening. A large change in HV interval is more likely to be associated with an already prolonged QRS duration before ablation and a lesser increase or even decrease in QRS duration after ablation. A shorter QRS duration before ablation is associated with a smaller HV interval increase following ablation but a greater increment in QRS duration. These findings are consistent with the concept that narrowness of QRS duration is due to synchronized activation of ventricular endocardium; whereas, QRS duration widening seen with His-Purkinje damage is due to reduced synchronization of endocardial activation. PMID:9633058
Assessment of Left Ventricular Dyssynchrony in Heart Failure Patients Regarding Underlying Etiology and QRS Duration
Montazeri, Mahdi; Rezvanfard, Mehrnaz; Kazemisaeid, Ali; Lotfi Tokaldany, Masoumeh; Mardanloo, Azam Safir; Darabi, Farzad; Fathollahi, Mahmood Sheikh; Sadeghian, Hakimeh
Background: Left ventricular (LV) dyssynchrony is a prevalent feature in heart failure (HF) patients. The current study aimed to evaluate the prevalence of inter and intraventricular dyssynchrony in HF patients with regard to the QRS duration and etiology. Methods: The available data on the tissue Doppler imaging (TDI) of 230 patients with refractory HF were analyzed. The patients were divided into three groups according to the QRS duration: QRS duration < 120 ms; 120¢150 ms; and ? 150 ms and the patients were re-categorized into two subgroups depending on the underlying etiology: ischemic cardiomyopathy (ICM) or dilated cardiomyopathy (DCM). The time-to-peak myocardial sustained systolic velocity (Ts) in six basal and six middle segments of the LV was measured manually using the velocity curves from TDI. LV dyssynchrony was defined as interventricular mechanical delay ? 40 ms and tissue Doppler velocity all segments delay ? 105 ms; standard deviation (SD) of all segments ? 34.4 ms; basal segments delay ? 78 ms; SD of basal segments ? 34.5 ms; and opposing wall delay ? 65 ms. Results: After adjustment for the possible confounders, interventricular dyssynchrony was more prevalent in the patients with QRS duration ? 150 ms than in those with QRS duration 120¢150 ms and < 120 ms. The patients with DCM also had a higher percentage of interventricular dyssynchrony than those with ICM in the wide QRS groups. Turning to the intraventricular dyssynchrony indices, the patients with QRS duration ? 150 ms and 120¢150 ms revealed a significantly greater delay between Ts at the basal and all segments than did those with QRS duration < 120 ms, while etiology did not influence the frequency of these indices in each QRS group. Conclusion: The prevalence of both inter and intraventricular dyssynchrony indices was greater in the patients with wide QRS than in those with narrow QRS duration. The underlying etiology may affect the frequency of interventricular but not intraventricular dyssynchrony indices. PMID:23074368
Detecting drug-induced prolongation of the QRS complex: New insights for cardiac safety assessment
Cros, C., E-mail: firstname.lastname@example.com [Safety Pharmacology, Global Safety Assessment, Safety Assessment UK, AstraZeneca R and D, Alderley Park, Macclesfield, SK10 4TG (United Kingdom); Skinner, M., E-mail: firstname.lastname@example.com [Safety Pharmacology, Global Safety Assessment, Safety Assessment UK, AstraZeneca R and D, Alderley Park, Macclesfield, SK10 4TG (United Kingdom); Moors, J. [Safety Pharmacology, Global Safety Assessment, Safety Assessment UK, AstraZeneca R and D, Alderley Park, Macclesfield, SK10 4TG (United Kingdom)] [Safety Pharmacology, Global Safety Assessment, Safety Assessment UK, AstraZeneca R and D, Alderley Park, Macclesfield, SK10 4TG (United Kingdom); Lainee, P. [Sanofi-Aventis R and D, 371, rue du Pr Joseph Blayac, 34184 Montpellier Cedex 04 (France)] [Sanofi-Aventis R and D, 371, rue du Pr Joseph Blayac, 34184 Montpellier Cedex 04 (France); Valentin, J.P. [Safety Pharmacology, Global Safety Assessment, Safety Assessment UK, AstraZeneca R and D, Alderley Park, Macclesfield, SK10 4TG (United Kingdom)] [Safety Pharmacology, Global Safety Assessment, Safety Assessment UK, AstraZeneca R and D, Alderley Park, Macclesfield, SK10 4TG (United Kingdom)
Background: Drugs slowing the conduction of the cardiac action potential and prolonging QRS complex duration by blocking the sodium current (I{sub Na}) may carry pro-arrhythmic risks. Due to the frequency-dependent block of I{sub Na}, this study assesses whether activity-related spontaneous increases in heart rate (HR) occurring during standard dog telemetry studies can be used to optimise the detection of class I antiarrhythmic-induced QRS prolongation. Methods: Telemetered dogs were orally dosed with quinidine (class Ia), mexiletine (class Ib) or flecainide (class Ic). QRS duration was determined standardly (5 beats averaged at rest) but also prior to and at the plateau of each acute increase in HR (3 beats averaged at steady state), and averaged over 1 h period from 1 h pre-dose to 5 h post-dose. Results: Compared to time-matched vehicle, at rest, only quinidine and flecainide induced increases in QRS duration (E{sub max} 13% and 20% respectively, P < 0.01¢0.001) whereas mexiletine had no effect. Importantly, the increase in QRS duration was enhanced at peak HR with an additional effect of + 0.7 ▒ 0.5 ms (quinidine, NS), + 1.8 ▒ 0.8 ms (mexiletine, P < 0.05) and + 2.8 ▒ 0.8 ms (flecainide, P < 0.01) (calculated as QRS at basal HR-QRS at high HR). Conclusion: Electrocardiogram recordings during elevated HR, not considered during routine analysis optimised for detecting QT prolongation, can be used to sensitise the detection of QRS prolongation. This could prove useful when borderline QRS effects are detected. Analysing during acute increases in HR could also be useful for detecting drug-induced effects on other aspects of cardiac function. -- Highlights: ? We aimed to improve detection of drug-induced QRS prolongation in safety screening. ? We used telemetered dogs to test class I antiarrhythmics at low and high heart rate. ? At low heart rate only quinidine and flecainide induced an increase in QRS duration. ? At high heart rate the effects of two out of three antiarrhythmics were enhanced. ? Detection of a drug-induced prolongation of QRS was improved at high heart rate.
Cardiac resynchronisation therapy in patients with heart failure and a normal QRS duration: the RESPOND study
Paul W X Foley; Kiran Patel; Nick Irwin; John E Sanderson; Michael P Frenneaux; Russell E A Smith; Berthold Stegemann; Francisco Leyva
ObjectivesTo evaluate the clinical response to cardiac resynchronisation therapy (CRT) in patients with heart failure and a normal QRS duration (<120 ms).SettingSingle centre.Patients60 patients with heart failure and a normal QRS duration receiving optimal pharmacological treatment (OPT).InterventionsPatients were randomly assigned to CRT (n=29) or to a control group (OPT, n=31). Cardiovascular magnetic resonance was used in order to avoid scar
Follow-Up After Pulmonary Valve Replacement in Adults With Tetralogy of Fallot Association Between QRS Duration and Outcome
R. W. C. Scherptong; M. G. Hazekamp; B. J. M. Mulder; O. Wijers; C. A. Swenne; Wall van der E. E; M. J. Schalij; H. W. Vliegen
Objectives The aim of this study was to analyze whether QRS duration, before and after pulmonary valve replacement (PVR), is related to long-term outcome in patients with tetralogy of Fallot (TOF). Background Key factors that determine outcome after PVR in adult TOF patients are largely unknown. Recognition of such factors assists the identification of patients at increased risk of adverse
Risk of Mortality Associated With QT and JT Intervals at Different Levels of QRS Duration (from the Third National Health and Nutrition Examination Survey).
Zulqarnain, Muhammad A; Qureshi, Waqas T; O'Neal, Wesley T; Shah, Amit J; Soliman, Elsayed Z
QT prolongation in the setting of QRS >120Āms is believed to be triggered by prolonged depolarization rather than repolarization. Hence, JT interval is suggested as an alternative to QT interval when QRS duration is prolonged. It is unclear, however, if JT and QT intervals portend similar risk of mortality for different durations of QRS. We examined the association between QT and JT, separately, with all-cause mortality across different levels of QRS duration in 8,025 participants (60 ▒ 13Āyears, 41% white and 54% women) from the Third National Health and Nutrition Examination Survey. At baseline (1986 to 1994), 486 participants (6%) had QRS duration ?120Āms. During a follow-up of up to 18Āyears, 3,045 deaths (38%) occurred. There were significant nonlinear relations of QT and JT intervals with mortality (p <0.001). Hence, QT and JT were categorized as prolonged (>95th percentile), shortened (<5th percentile), and normal (reference group). In multivariate-adjusted Cox regression models, prolonged JT (hazard ratio [HR] 4.75, 95% confidence interval [CI] 1.86 to 12.11) was associated with increased risk of mortality more than prolonged QT (HR 1.50, 95% CI 1.03 to 2.17) in participants with QRS ?120Āms (interaction pĀ= 0.02). In participants with QRS duration <120Āms, prolonged QT and JT were equally predictive of all-cause mortality (HR 1.27, 95% CI 1.06 to 1.54, and HR 1.31, 95% CI 1.10 to 1.55, respectively). Similar patterns were observed with shortened QT and JT intervals. In conclusion, although both QT and JT intervals are predictive of mortality, JT is more predictive in the setting of QRS duration >120Āms supporting the use of JT interval in patients with prolonged QRS. PMID:25929581
A new mathematical based QRS detector using continuous wavelet transform
A. Ghaffari; H. Golbayani; M. Ghasemi
In this paper, a new viewpoint in ECG detection is presented using continuous wavelet transform (CWT). In order to magnify QRS complex and reduce the effects of other peaks, the concept of dominant rescaled wavelet coefficients (DRWC) is defined. Using this concept, the relations between the time duration of components of a QRS complex and their wavelet transforms are derived
An efficient unsupervised fetal QRS complex detection from abdominal maternal ECG.
Varanini, M; Tartarisco, G; Billeci, L; Macerata, A; Pioggia, G; Balocchi, R
Non-invasive fetal heart rate is of great relevance in clinical practice to monitor fetal health state during pregnancy. To date, however, despite significant advances in the field of electrocardiography, the analysis of abdominal fetal ECG is considered a challenging problem for biomedical and signal processing communities. This is mainly due to the low signal-to-noise ratio of fetal ECG and difficulties in cancellation of maternal QRS complexes, motion and electromyographic artefacts. In this paper we present an efficient unsupervised algorithm for fetal QRS complex detection from abdominal multichannel signal recordings combining ICA and maternal ECG cancelling, which outperforms each single method. The signal is first pre-processed to remove impulsive artefacts, baseline wandering and power line interference. The following steps are then applied: maternal ECG extraction through independent component analysis (ICA); maternal QRS detection; maternal ECG cancelling through weighted singular value decomposition; enhancing of fetal ECG through ICA and fetal QRS detection. We participated in the Physionet/Computing in Cardiology Challenge 2013, obtaining the top official scores of the challenge (among 53 teams of participants) of event 1 and event 2 concerning fetal heart rate and fetal interbeat intervals estimation section. The developed algorithms are released as open-source on the Physionet website. PMID:25069520
Common variants in 22 loci are associated with QRS duration and cardiac ventricular conduction
Aaron Isaacs; Paul I W de Bakker; Marcus D÷rr; Christopher Newton-Cheh; Ilja M Nolte; Pim van der Harst; Martina M³ller; Mark Eijgelsheim; Alvaro Alonso; Andrew A Hicks; Sandosh Padmanabhan; Caroline Hayward; Albert Vernon Smith; Ozren Polasek; Steven Giovannone; Jingyuan Fu; Jared W Magnani; Kristin D Marciante; Arne Pfeufer; Sina A Gharib; Alexander Teumer; Man Li; Joshua C Bis; Fernando Rivadeneira; Thor Aspelund; Anna K÷ttgen; Toby Johnson; Kenneth Rice; Mark P S Sie; Ying A Wang; Norman Klopp; Christian Fuchsberger; Sarah H Wild; Irene Mateo Leach; Karol Estrada; Uwe V÷lker; Alan F Wright; Folkert W Asselbergs; Jiaxiang Qu; Aravinda Chakravarti; Moritz F Sinner; Jan A Kors; Astrid Petersmann; Tamara B Harris; Elsayed Z Soliman; Patricia B Munroe; Bruce M Psaty; Ben A Oostra; L Adrienne Cupples; Siegfried Perz; Rudolf A de Boer; Andrķ G Uitterlinden; Henry V÷lzke; Timothy D Spector; Fang-Yu Liu; Eric Boerwinkle; Anna F Dominiczak; Jerome I Rotter; Gķ van Herpen; Daniel Levy; H-Erich Wichmann; Wiek H van Gilst; Jacqueline C M Witteman; Heyo K Kroemer; W H Linda Kao; Susan R Heckbert; Thomas Meitinger; Albert Hofman; Harry Campbell; Aaron R Folsom; Dirk J van Veldhuisen; Christine Schwienbacher; Christopher J O'Donnell; Claudia Beu Volpato; Mark J Caulfield; John M Connell; Lenore Launer; Xiaowen Lu; Lude Franke; Rudolf S N Fehrmann; Gerard te Meerman; Harry J M Groen; Rinse K Weersma; Leonard H van den Berg; Cisca Wijmenga; Roel A Ophoff; Gerjan Navis; Igor Rudan; Harold Snieder; James F Wilson; Peter P Pramstaller; David S Siscovick; Thomas J Wang; Vilmundur Gudnason; Cornelia M van Duijn; Stephan B Felix; Glenn I Fishman; Yalda Jamshidi; Bruno H Ch Stricker; Nilesh J Samani; Nona Sotoodehnia; Stefan Kõõb; Dan E Arking
The QRS interval, from the beginning of the Q wave to the end of the S wave on an electrocardiogram, reflects ventricular depolarization and conduction time and is a risk factor for mortality, sudden death and heart failure. We performed a genome-wide association meta-analysis in 40,407 individuals of European descent from 14 studies, with further genotyping in 7,170 additional Europeans,
Fragmented QRS: What Is The Meaning?
Take, Yutaka; Morita, Hiroshi
Fragmented QRS (fQRS) is a convenient marker of myocardial scar evaluated by 12-lead electrocardiogram (ECG) recording. fQRS is defined as additional spikes within the QRS complex. In patients with CAD, fQRS was associated with myocardial scar detected by single photon emission tomography and was a predictor of cardiac events. fQRS was also a predictor of mortality and arrhythmic events in patients with reduced left ventricular function. The usefulness of fQRS for detecting myocardial scar and for identifying high-risk patients has been expanded to various cardiac diseases, such as cardiac sarcoidosis, arrhythmogenic right ventricular cardiomyopathy, acute coronary syndrome, Brugada syndrome, and acquired long QT syndrome. fQRS can be applied to patients with wide QRS complexes and is associated with myocardial scar and prognosis. Myocardial scar detected by fQRS is associated with subsequent ventricular dysfunction and heart failure and is a substrate for reentrant ventricular tachyarrhythmias. PMID:23071383
3DQRS: A method to obtain reliable QRS complex detection within high field MRI using 12-lead ECG traces
Gregory, T. Stan; Schmidt, Ehud J.; Zhang, Shelley Hualei; Tse, Zion Tsz Ho
Purpose To develop a technique that accurately detects the QRS complex in 1.5T, 3T and 7T MRI scanners.ö Theory and Methods During early systole, blood is rapidly ejected into the aortic arch, traveling perpendicular to the MRIÆs main field, which produces a strong voltage (VMHD) that eclipses the QRS complex. Greater complexity arises in arrhythmia patients, since VMHD can vary between sinus-rhythm and arrhythmic beats. The 3DQRS method uses a kernel consisting of 6 ECG precordial leads, compiled from a 12-lead ECG performed outside the magnet. The kernel is cross-correlated with signals acquired inside the MRI in order to identify the QRS complex in real time. The 3DQRS method was evaluated against a Vectorcardiogram-based (VCG) approach in 2 Premature Ventricular Contraction (PVC) and 2 Atrial Fibrillation (AF) patients, a healthy exercising athlete and 8 healthy volunteers, within 1.5T and 3T MRIs, using a prototype MRI-conditional 12 lead ECG system. 2 volunteers were recorded at 7T using a Holter recorder. Results For QRS complex detection, 3DQRS subject-averaged sensitivity levels, relative to VCG were: 1.5T (100% vs. 96.7%), 3T (98.9% vs. 92.2%), 7T (96.2% vs. 77.7%). Conclusions The 3DQRS method was shown to be more effective in cardiac gating than a conventional VCG-based method. PMID:24453116
Radial dyssynchrony assessed by cardiovascular magnetic resonance in relation to left ventricular function, myocardial scarring and QRS duration in patients with heart failure
Background Intuitively, cardiac dyssynchrony is the inevitable result of myocardial injury. We hypothezised that radial dyssynchrony reflects left ventricular remodeling, myocardial scarring, QRS duration and impaired LV function and that, accordingly, it is detectable in all patients with heart failure. Methods 225 patients with heart failure, grouped according to QRS duration of <120 ms (A, n = 75), between 120-149 ms (B, n = 75) or ?150 ms (C, n = 75), and 50 healthy controls underwent assessment of radial dyssynchrony using the cardiovascular magnetic resonance tissue synchronization index (CMR-TSI = SD of time to peak inward endocardial motion in up to 60 myocardial segments). Results Compared to 50 healthy controls (21.8 ▒ 6.3 ms [mean ▒ SD]), CMR-TSI was higher in A (74.8 ▒ 34.6 ms), B (92.4 ▒ 39.5 ms) and C (104.6 ▒ 45.6 ms) (all p < 0.0001). Adopting a cut-off CMR-TSI of 34.4 ms (21.8 plus 2xSD for controls) for the definition of dyssynchrony, it was present in 91% in A, 95% in B and 99% in C. Amongst patients in NYHA class III or IV, with a LVEF<35% and a QRS>120 ms, 99% had dyssynchrony. Amongst those with a QRS<120 ms, 91% had dyssynchrony. Across the study sample, CMR-TSI was related positively to left ventricular volumes (p < 0.0001) and inversely to LVEF (CMR-TSI = 178.3 e (-0.033 LVEF) ms, p < 0.0001). Conclusion Radial dyssynchrony is almost universal in patients with heart failure. This vies against the notion that a lack of response to CRT is related to a lack of dyssynchrony. PMID:19930713
A multi-step method with signal quality assessment and fine-tuning procedure to locate maternal and fetal QRS complexes from abdominal ECG recordings.
Liu, Chengyu; Li, Peng; Di Maria, Costanzo; Zhao, Lina; Zhang, Henggui; Chen, Zhiqing
Non-invasive monitoring of fetal electrocardiogram (fECG) plays an important role in detecting and diagnosing fetal diseases. This study aimed to develop a multi-step method for locating both maternal and fetal QRS complexes from abdominal ECG (aECG) recordings. The proposed method included four major steps: abdominal ECG pre-processing, maternal QRS complex locating, maternal ECG cancellation and fetal QRS complex locating. Signal quality assessment (SQA) and fine-tuning for maternal ECG (FTM) were implemented in the first and third steps, respectively. The method was then evaluated using 75 non-invasive 4-channel aECG recordings provided by the PhysioNet/Computing in Cardiology Challenge 2013. The F1 measure, which is a new index introduced by Behar et al (2013 Proc. Comput. Cardiol. 40 297-300), was used to assess the locating accuracy. The other two indices, mean squared error of heart rate (MSE_HR) between the fetal HR signals estimated from the reference and our method (MSE_HR in bpm(2)) and root mean squared difference between the corresponding fetal RR intervals (MSE_RR in ms) were also used to assess the locating accuracy. Overall,Āfor the maternal QRS complex, the F1 measure was 98.4% from the method without the implementation of SQA, and it was improved to 99.8% with SQA. For the fetal QRS complex, the F1 measure, MSE_HR and MSE_RR were 84.9%, 185.6?bpm(2) and 19.4?ms for the method without both SQA and FTM procedures. They were improved to 93.9%, 47.5?bpm(2) and 7.6?ms with both SQA and FTM procedures. These improvements were observed from each individual subject. It can be concluded that implementing both SQA and FTM procedures could achieve better performance for locating both maternal and fetal QRS complexes. PMID:25069817
High Frequency QRS ECG Accurately Detects Cardiomyopathy
NASA Technical Reports Server (NTRS)
Schlegel, Todd T.; Arenare, Brian; Poulin, Gregory; Moser, Daniel R.; Delgado, Reynolds
High frequency (HF, 150-250 Hz) analysis over the entire QRS interval of the ECG is more sensitive than conventional ECG for detecting myocardial ischemia. However, the accuracy of HF QRS ECG for detecting cardiomyopathy is unknown. We obtained simultaneous resting conventional and HF QRS 12-lead ECGs in 66 patients with cardiomyopathy (EF = 23.2 plus or minus 6.l%, mean plus or minus SD) and in 66 age- and gender-matched healthy controls using PC-based ECG software recently developed at NASA. The single most accurate ECG parameter for detecting cardiomyopathy was an HF QRS morphological score that takes into consideration the total number and severity of reduced amplitude zones (RAZs) present plus the clustering of RAZs together in contiguous leads. This RAZ score had an area under the receiver operator curve (ROC) of 0.91, and was 88% sensitive, 82% specific and 85% accurate for identifying cardiomyopathy at optimum score cut-off of 140 points. Although conventional ECG parameters such as the QRS and QTc intervals were also significantly longer in patients than controls (P less than 0.001, BBBs excluded), these conventional parameters were less accurate (area under the ROC = 0.77 and 0.77, respectively) than HF QRS morphological parameters for identifying underlying cardiomyopathy. The total amplitude of the HF QRS complexes, as measured by summed root mean square voltages (RMSVs), also differed between patients and controls (33.8 plus or minus 11.5 vs. 41.5 plus or minus 13.6 mV, respectively, P less than 0.003), but this parameter was even less accurate in distinguishing the two groups (area under ROC = 0.67) than the HF QRS morphologic and conventional ECG parameters. Diagnostic accuracy was optimal (86%) when the RAZ score from the HF QRS ECG and the QTc interval from the conventional ECG were used simultaneously with cut-offs of greater than or equal to 40 points and greater than or equal to 445 ms, respectively. In conclusion 12-lead HF QRS ECG employing RAZ scoring is a simple, accurate and inexpensive screening technique for cardiomyopathy. Although HF QRS ECG is highly sensitive for cardiomyopathy, its specificity may be compromised in patients with cardiac pathologies other than cardiomyopathy, such as uncomplicated coronary artery disease or multiple coronary disease risk factors. Further studies are required to determine whether HF QRS might be useful for monitoring cardiomyopathy severity or the efficacy of therapy in a longitudinal fashion.
Spatio-temporal Filtering for Fetal QRS Enhancement
M. Kotas; J. Je?ewski; A. Matonia; T. Kupka
\\u000a We propose a new approach to maternal ECG suppression and fetal QRS detection in the multi-channel maternal abdominal bioelectric\\u000a signals. First, a single-channel method based on template subtraction is applied to suppress the maternal ECG in the respective\\u000a channels. Then we use spatial or spatio-temporal filtering to enhance the fetal QRS complexes. Finally, the QRS detection\\u000a is performed. In the
A Randomized Controlled Trial to Evaluate the Safety and Efficacy of Cardiac Contractility Modulation in Patients With Moderately Reduced Left Ventricular Ejection Fraction and a Narrow QRS Duration: Study Rationale and Design
Cardiac contractility modulation (CCM) signals are nonexcitatory electrical signals delivered during the cardiac absolute refractory period that enhance the strength of cardiac muscular contraction. The FIX-HF-5 study was a prospective randomized study comparing CCM plus optimal medical therapy (OMT) to OMT alone that included 428 New York Heart Association (NYHA) functional class III or IV heart failure patients with ejection fraction (EF) ?45% according to core laboratory assessment. The study met its primary safety end point, but did not reach its primary efficacy end point: a responders analysis of changes in ventilatory anaerobic threshold (VAT). However, in a prespecified subgroup analysis, significant improvements in primary and secondary end points, including the responder VAT end point, were observed in patients with EFs ranging from 25% to 45%, who constituted about one-half of the study subjects. We therefore designed a new study to prospectively confirm the efficacy of CCM in this population. A hierarchic bayesian statistical analysis plan was developed to take advantage of the data already available from the first study. In addition, based on technical difficulties encountered in reliably quantifying VAT and the relatively large amount of nonquantifiable studies, the primary efficacy end point was changed to peak VO2, with significant measures incorporated to minimize the influence of placebo effect. In this paper, we provide the details and rationale of the FIX-HF-5C study design to study CCM plus OMT compared with OMT alone in subjects with normal QRS duration, NYHA functional class III or IV, and EF 25%¢45%. This study is registered on www.clinicaltrials.gov with identifier no. NCT01381172. PMID:25285748
Real-time, high frequency QRS electrocardiograph
NASA Technical Reports Server (NTRS)
Schlegel, Todd T. (Inventor); DePalma, Jude L. (Inventor); Moradi, Saeed (Inventor)
Real time cardiac electrical data are received from a patient, manipulated to determine various useful aspects of the ECG signal, and displayed in real time in a useful form on a computer screen or monitor. The monitor displays the high frequency data from the QRS complex in units of microvolts, juxtaposed with a display of conventional ECG data in units of millivolts or microvolts. The high frequency data are analyzed for their root mean square (RMS) voltage values and the discrete RMS values and related parameters are displayed in real time. The high frequency data from the QRS complex are analyzed with imbedded algorithms to determine the presence or absence of reduced amplitude zones, referred to herein as RAZs. RAZs are displayed as go, no-go signals on the computer monitor. The RMS and related values of the high frequency components are displayed as time varying signals, and the presence or absence of RAZs may be similarly displayed over time.
Physionet Challenge 2011: Improving the quality of electrocardiography data collected using real time QRS-complex and T-Wave detection
Thomas Ho Chee Tat; Chen Xiang; Lim Eng Thiam
The Physionet Challenge [1] focused on discerning between usable and unusable electrocardiography (ECG) data tele-medically from mobile embedded devices. Based on our publications [2,3,4], we have designed a method to determine the quality of ECG data and its usability using an adaptation of the Tompkins et al [5] real time QRS detection algorithm. With our modifications to the algorithm to
QRS Prolongation in Myotonic Muscular Dystrophy and Diffuse Fibrosis on Cardiac Magnetic Resonance
Nazarian, Saman; Bluemke, David A.; Wagner, Kathryn R.; Zviman, Menekhem M.; Turkbey, Evrim; Caffo, Brian S.; Shehata, Monda; Edwards, David; Butcher, Barbara; Calkins, Hugh; Berger, Ronald D.; Halperin, Henry R.; Tomaselli, Gordon F.
Current noninvasive surrogates of cardiac involvement in myotonic muscular dystrophy have low positive predictive value for sudden death. We hypothesized that the cardiac MR signal-to-noise ratio variance (SNRV) is a surrogate of the spatial heterogeneity of myocardial fibrosis and correlates with electrocardiography changes in myotonic muscular dystrophy. The SNRV for contrast enhanced cardiac MR images was calculated over the entire left ventricle in 43 patients with myotonic muscular dystrophy. All patients underwent standard electrocardiography, and a subset of 23 patients underwent signal averaged electrocardiography. After correcting for body mass index, age, and ejection fraction, SNRV was predictive of QRS duration on standard electrocardiography (1.35-msec increased QRS duration/unit increase in SNRV, P < 0.001). SNRV was also predictive of the low-amplitude late-potential duration (1.49-msec increased low-amplitude late-potential duration/unit increase in SNRV, P < 0.001). Ten-fold cross-validation yielded an area under the receiver operating characteristic curve of 0.87 for the predictive value of SNRV for QRS duration greater than 120 msec. The SNRV of the left ventricle is associated with QRS prolongation, likely due to late depolarization of tissue within islands of patchy fibrosis. The association of SNRV with future clinical events warrants further study. PMID:20572151
The Presence of Fragmented QRS on 12-Lead Electrocardiography in Patients with Coronary Artery Ectasia
Sen, Fatih; Kuyumcu, Mevl³t Serdar; ųzeke, ųzcan; Balc?, Mustafa M³cahit; Aydo?du, Sinan
Background and Objectives Coronary artery ectasia (CAE) is an angiographic finding characterized by dilation of an arterial segment with a diameter at least 1.5 times that of its adjacent normal coronary artery. Fragmented QRS (fQRS) complexes are electrocardiographic signals which reflect altered ventricular conduction around regions of a myocardial scar and/or ischaemia. In the present study, we aimed to evaluate the presence of fQRS in patients with CAE. Subjects and Methods The study population included 100 patients with isolated CAE without coronary artery disease (CAD) and 80 angiographically normal controls. fQRS was defined as the presence of an additional R wave or notching of R or S wave or the presence of fragmentation in two contiguous leads corresponding to a major coronary artery territory. Results The two groups were similar in terms of age, sex, hypertension, dyslipidemia, and family history of CAD. The presence of fQRS was significantly (p<0.05) higher in the CAE group than that in the normal coronary artery group (29% vs. 6.2%, p=0.008). Isolated CAE were detected most commonly in the right coronary artery (61%), followed by left anterior descending artery (52%), left circumflex artery (36%), and left main artery (9%). Multivariate stepwise logistic regression analysis showed that CAE {odds ratio (OR) 1.412; 95% confidence interval (CI) 1.085-1.541; p=0.003} and diabetes (OR 1.310; 95% CI 1.025-1.482; p=0.041) were independently associated with fQRS. Conclusion The presence of fragmented QRS associated with increased risk for arrhythmias and cardiovascular mortality was significantly higher in patients with CAE than in patient with normal coronary artery. Further studies are needed to determine whether the presence of fragmented QRS is a possible new risk factor for patients with CAE. PMID:25278983
Principal component model for maternal ECG extraction in fetal QRS detection.
Lipponen, Jukka A; Tarvainen, Mika P
Fetal cardiac monitoring using noninvasive abdominal leads can provide important information on fetal well-being. However, extraction of fetal electrocardiogram (fECG) from abdominal signals is often problematic because of the higher amplitude maternal ECG (mECG). The aim of this study was to introduce a principal component model for removing the maternal ECG from abdominal signals. The proposed method removes mECG waveforms with high accuracy even though abdominal movements cause morphological deviation to mECG complexes. The method can be used for single or multi-lead measurements. The proposed method was tested using 175 1Āmin long abdominal measurements with fetal QRS annotation markers acquired from a fetal scalp electrode. Using the presented mECG removing algorithm and matched filtering based fQRS detector, 95% sensitivity for fQRS detection and 4.84Āms RMS error for fetal RR-interval estimation were acquired. PMID:25069651
Factors affecting the duration effect in pitch perception for unresolved complex tones
NASA Astrophysics Data System (ADS)
White, Louise J.; Plack, Christopher J.
Previous research has shown that fundamental frequency (F0) discrimination thresholds for complex tones containing unresolved harmonics decrease as the duration of the tone increases [White and Plack, J. Acoust. Soc. Am. 103, 2051-2063 (1998)]. In this paper F0 discrimination was measured as a function of duration for complexes with F0s of 62.5, 125, and 250 Hz, bandpass filtered into two spectral regions (2750-3750 and 5500-7500 Hz). The harmonics were summed either in sine phase (SINE) or with alternating sine-cosine phase (ALT), which affects the envelope of the waveform and the pitch of the complex. Tone duration was 20, 40, 80, and 160 ms. The improvement in F0 discrimination with duration increased with decreasing F0. When harmonics where spectrally filtered between 2750 and 3750 Hz, for complexes with an F0 of 62.5 Hz, F0 discrimination thresholds decreased from approximately 30% for a 20-ms tone to approximately 3% for a 160-ms tone. For complexes with an F0 of 250 Hz, thresholds decreased from 3% for a 20-ms tone to 1% for a 160-ms tone: a lower envelope repetition rate led to a larger change in performance with increasing duration. The phase manipulation also affected the size of the duration effect, in that the effect was less for an ALT complex compared to a SINE complex with the same F0, consistent with the change in envelope repetition rate. Overall, the results suggest that for unresolved complex tones it is primarily envelope repetition rate, not spectral region, that determines both the F0 discrimination threshold and the size of the duration effect.
A method for context-based adaptive QRS clustering in real-time.
Castro, Daniel; Felix, Paulo; Presedo, Jesus
Continuous follow-up of heart condition through long-term electrocardiogram monitoring is an invaluable tool for diagnosing some cardiac arrhythmias. In such context, providing tools for fast locating alterations of normal conduction patterns is mandatory and still remains an open issue. This work presents a real-time method for adaptive clustering QRS complexes from multilead ECG signals that provides the set of QRS morphologies that appear during an ECG recording. The method processes the QRS complexes sequentially, grouping them into a dynamic set of clusters based on the information content of the temporal context. The clusters are represented by templates which evolve over time and adapt to the QRS morphology changes. Rules to create, merge and remove clusters are defined along with techniques for noise detection in order to avoid their proliferation. To cope with beat misalignment, Derivative Dynamic Time Warping is used. The proposed method has been validated against the MIT-BIH Arrhythmia Database and the AHA ECG Database showing a global purity of 98.56% and 99.56%, respectively. Results show that our proposal not only provides better results than previous offline solutions but also fulfills real-time requirements. PMID:25312964
Identification of post-myocardial infarction patients prone to ventricular tachycardia using time¢frequency analysis of QRS and ST segments
J.-P. Couderc; P. Chevalier; J. Fayn; P. Rubel; P. Touboul
Background Late potentials (LPs) in the terminal portion of the QRS complex are commonly sought to identify post-myocardial infarction patients prone to ventricular tachyarrthythmias (VT) or sudden death. More recent time¢frequency signal processing tools have been shown to provide new parameters for the quantification of LPs and abnormal activities buried within the QRS complex.Methods and Results The study population comprised
Revisiting QRS Detection Methodologies for Portable, Wearable, Battery-Operated, and Wireless ECG Systems
Elgendi, Mohamed; Eskofier, Bj÷rn; Dokos, Socrates; Abbott, Derek
Cardiovascular diseases are the number one cause of death worldwide. Currently, portable battery-operated systems such as mobile phones with wireless ECG sensors have the potential to be used in continuous cardiac function assessment that can be easily integrated into daily life. These portable point-of-care diagnostic systems can therefore help unveil and treat cardiovascular diseases. The basis for ECG analysis is a robust detection of the prominent QRS complex, as well as other ECG signal characteristics. However, it is not clear from the literature which ECG analysis algorithms are suited for an implementation on a mobile device. We investigate current QRS detection algorithms based on three assessment criteria: 1) robustness to noise, 2) parameter choice, and 3) numerical efficiency, in order to target a universal fast-robust detector. Furthermore, existing QRS detection algorithms may provide an acceptable solution only on small segments of ECG signals, within a certain amplitude range, or amid particular types of arrhythmia and/or noise. These issues are discussed in the context of a comparison with the most conventional algorithms, followed by future recommendations for developing reliable QRS detection schemes suitable for implementation on battery-operated mobile devices. PMID:24409290
New Hampshire Quality Rating System: QRS Profile. The Child Care Quality Rating System (QRS) Assessment
ERIC Educational Resources Information Center
Child Trends, 2010
This paper presents a profile of New Hampshire's Quality Rating System prepared as part of the Child Care Quality Rating System (QRS) Assessment Study. The profile consists of several sections and their corresponding descriptions including: (1) Program Information; (2) Rating Details; (3) Quality Indicators for Center-Based Programs; (4)ģ
Virginia Star Quality Initiative: QRS Profile. The Child Care Quality Rating System (QRS) Assessment
ERIC Educational Resources Information Center
Child Trends, 2010
This paper presents a profile of Virginia's Star Quality Initiative prepared as part of the Child Care Quality Rating System (QRS) Assessment Study. The profile consists of several sections and their corresponding descriptions including: (1) Program Information; (2) Rating Details; (3) Quality Indicators for Center-Based Programs; (4) Indicatorsģ
Oregon Child Care Quality Indicators Program: QRS Profile. The Child Care Quality Rating System (QRS) Assessment
ERIC Educational Resources Information Center
Child Trends, 2010
This paper presents a profile of Oregon's Child Care Quality Indicators Program prepared as part of the Child Care Quality Rating System (QRS) Assessment Study. The profile consists of several sections and their corresponding descriptions including: (1) Program Information; (2) Rating Details; (3) Quality Indicators for Center-Based Programs; (4)ģ
Pennsylvania Keystone STARS: QRS Profile. The Child Care Quality Rating System (QRS) Assessment
ERIC Educational Resources Information Center
Child Trends, 2010
This paper presents a profile of Pennsylvania's Keystone STARS prepared as part of the Child Care Quality Rating System (QRS) Assessment Study. The profile consists of several sections and their corresponding descriptions including: (1) Program Information; (2) Rating Details; (3) Quality Indicators for Center-Based Programs; (4) Indicators forģ
Colorado Qualistar. QRS Profile. The Child Care Quality Rating System (QRS) Assessment
ERIC Educational Resources Information Center
Child Trends, 2010
This paper presents a profile of Colorado's Qualistar prepared as part of the Child Care Quality Rating System (QRS) Assessment Study. The profile consists of several sections and their corresponding descriptions including: (1) Program Information; (2) Rating Details; (3) Quality Indicators for Center-Based Programs; (4) Indicators for Familyģ
Illinois Quality Counts: QRS Profile. The Child Care Quality Rating System (QRS) Assessment
ERIC Educational Resources Information Center
Child Trends, 2010
This paper presents a profile of Illinois' Quality Counts prepared as part of the Child Care Quality Rating System (QRS) Assessment Study. The profile consists of several sections and their corresponding descriptions including: (1) Program Information; (2) Rating Details; (3) Quality Indicators for Center-Based Programs; (4) Indicators for Familyģ
Minnesota Parent Aware: QRS Profile. The Child Care Quality Rating System (QRS) Assessment
ERIC Educational Resources Information Center
Child Trends, 2010
This paper presents a profile of Minnesota's Parent Aware prepared as part of the Child Care Quality Rating System (QRS) Assessment Study. The profile consists of several sections and their corresponding descriptions including: (1) Program Information; (2) Rating Details; (3) Quality Indicators for Center-Based Programs; (4) Indicators for Familyģ
Iowa Child Care Quality Rating System: QRS Profile. The Child Care Quality Rating System (QRS) Assessment
ERIC Educational Resources Information Center
Child Trends, 2010
This paper presents a profile of Iowa's Child Care Quality Rating System prepared as part of the Child Care Quality Rating System (QRS) Assessment Study. The profile is divided into the following categories: (1) Program Information; (2) Rating Details; (3) Quality Indicators for Center-Based Programs; (4) Indicators for Family Child Care Programs;ģ
Miami-Dade Quality Counts: QRS Profile. The Child Care Quality Rating System (QRS) Assessment
ERIC Educational Resources Information Center
Child Trends, 2010
This paper presents a profile of Miami-Dade's Quality Counts prepared as part of the Child Care Quality Rating System (QRS) Assessment Study. The profile consists of several sections and their corresponding descriptions including: (1) Program Information; (2) Rating Details; (3) Quality Indicators for Center-Based Programs; (4) Indicators forģ
Purkinje-cell plasticity and cerebellar motor learning are graded by complex-spike duration.
Yang, Yan; Lisberger, Stephen G
Behavioural learning is mediated by cellular plasticity, such as changes in the strength of synapses at specific sites in neural circuits. The theory of cerebellar motor learning relies on movement errors signalled by climbing-fibre inputs to cause long-term depression of synapses from parallel fibres to Purkinje cells. However, a recent review has called into question the widely held view that the climbing-fibre input is an 'all-or-none' event. In anaesthetized animals, there is wide variation in the duration of the complex spike (CS) caused in Purkinje cells by a climbing-fibre input. Furthermore, the amount of plasticity in Purkinje cells is graded according to the duration of electrically controlled bursts in climbing fibres. The duration of bursts depends on the 'state' of the inferior olive and therefore may be correlated across climbing fibres. Here we provide a potential functional context for these mechanisms during motor learning in behaving monkeys. The magnitudes of both plasticity and motor learning depend on the duration of the CS responses. Furthermore, the duration of CS responses seems to be a meaningful signal that is correlated across the Purkinje-cell population during motor learning. We suggest that during learning, longer bursts in climbing fibres lead to longer-duration CS responses in Purkinje cells, more calcium entry into Purkinje cells, larger synaptic depression, and stronger learning. The same graded impact of instructive signals for plasticity and learning might occur throughout the nervous system. PMID:24814344
Real-time, high frequency QRS electrocardiograph with reduced amplitude zone detection
NASA Technical Reports Server (NTRS)
Schlegel, Todd T. (Inventor); DePalma, Jude L. (Inventor); Moradi, Saeed (Inventor)
Real time cardiac electrical data are received from a patient, manipulated to determine various useful aspects of the ECG signal, and displayed in real time in a useful form on a computer screen or monitor. The monitor displays the high frequency data from the QRS complex in units of microvolts, juxtaposed with a display of conventional ECG data in units of millivolts or microvolts. The high frequency data are analyzed for their root mean square (RMS) voltage values and the discrete RMS values and related parameters are displayed in real time. The high frequency data from the QRS complex are analyzed with imbedded algorithms to determine the presence or absence of reduced amplitude zones, referred to herein as ''RAZs''. RAZs are displayed as ''go, no-go'' signals on the computer monitor. The RMS and related values of the high frequency components are displayed as time varying signals, and the presence or absence of RAZs may be similarly displayed over time.
Noninvasive fetal QRS detection using an echo state network and dynamic programming.
LukoÜevi?ius, Mantas; Marozas, Vaidotas
We address a classical fetal QRS detection problem from abdominal ECG recordings with a data-driven statistical machine learning approach. Our goal is to have a powerful, yet conceptually clean, solution. There are two novel key components at the heart of our approach: an echo state recurrent neural network that is trained to indicate fetal QRS complexes, and several increasingly sophisticated versions of statistics-based dynamic programming algorithms, which are derived from and rooted in probability theory. We also employ a standard technique for preprocessing and removing maternal ECG complexes from the signals, but do not take this as the main focus of this work. The proposed approach is quite generic and can be extended to other types of signals and annotations. Open-source code is provided. PMID:25069892
Real-Time 12-Lead High-Frequency QRS Electrocardiography for Enhanced Detection of Myocardial Ischemia and Coronary Artery Disease
NASA Technical Reports Server (NTRS)
Schlegel, Todd T.; Kulecz, Walter B.; DePalma, Jude L.; Feiveson, Alan H.; Wilson, John S.; Rahman, M. Atiar; Bungo, Michael W.
Several studies have shown that diminution of the high-frequency (HF; 150-250 Hz) components present within the central portion of the QRS complex of an electrocardiogram (ECG) is a more sensitive indicator for the presence of myocardial ischemia than are changes in the ST segments of the conventional low-frequency ECG. However, until now, no device has been capable of displaying, in real time on a beat-to-beat basis, changes in these HF QRS ECG components in a continuously monitored patient. Although several software programs have been designed to acquire the HF components over the entire QRS interval, such programs have involved laborious off-line calculations and postprocessing, limiting their clinical utility. We describe a personal computer-based ECG software program developed recently at the National Aeronautics and Space Administration (NASA) that acquires, analyzes, and displays HF QRS components in each of the 12 conventional ECG leads in real time. The system also updates these signals and their related derived parameters in real time on a beat-to-beat basis for any chosen monitoring period and simultaneously displays the diagnostic information from the conventional (low-frequency) 12-lead ECG. The real-time NASA HF QRS ECG software is being evaluated currently in multiple clinical settings in North America. We describe its potential usefulness in the diagnosis of myocardial ischemia and coronary artery disease.
The case of the QRS-T angles versus QRST integral maps.
van Oosterom, Adriaan
This contribution discusses the QRS-T angle as well as the QRST integral map. Both of these topics have been tested in their application in extracting the major features of depolarization and repolarization: their spatio-temporal behaviour, and how much of their global or local nature might be deduced from signals that can be observed clinically. Recently, it is in particular the QRS-T angle that has received considerable attention, a method that stems directly from vectorcardiography, a subdomain of electrocardiography. The QRST integral map is a display of a map on the body surface of the integrals over time of the ECG signals observed at sets of electrodes. The common biophysical background of both techniques is highlighted. In particular it is explained why, in healthy myocardium, both provide a similar view on the global timing of the depolarization and repolarization of all cardiac myocytes, more specifically, on the dispersion of their action potential durations. In the presence of ischemia, the view obtained is of the integral over time of the transmembrane potentials, which comprises a 'mixture' of their timing and magnitude. The analysis of results of a simulation study emphasizes the large discrepancies that may be observed between the QRS-T angle in the frontal plane and its 3D variant. It is shown that the required vector representation of the signals may be derived from the 12-lead ECG by using the transfer matrix proposed in 1990 by Kors and colleagues. PMID:24360344
MS no 04/102 Evaluation of real-time QRS detection
Boyer, Edmond
morphologies and clinical noise. Four QRS detectors are compared under these contexts by means to the QRS detectors, without noise, and with 3 different types of additive clinical noise (electrode motion the best QRS detector according to the current context. Keywords: ECG analysis, QRS detection, algorithms
Fetal QRS extraction from abdominal recordings via model-based signal processing and intelligent signal merging.
Haghpanahi, Masoumeh; Borkholder, David A
Noninvasive fetal ECG (fECG) monitoring has potential applications in diagnosing congenital heart diseases in a timely manner and assisting clinicians to make more appropriate decisions during labor. However, despite advances in signal processing and machine learning techniques, the analysis of fECG signals has still remained in its preliminary stages. In this work, we describe an algorithm to automatically locate QRS complexes in noninvasive fECG signals obtained from a set of four electrodes placed on the mother's abdomen. The algorithm is based on an iterative decomposition of the maternal and fetal subspaces and filtering of the maternal ECG (mECG) components from the fECG recordings. Once the maternal components are removed, a novel merging technique is applied to merge the signals and detect the fetal QRS (fQRS) complexes. The algorithm was trained and tested on the fECG datasets provided by the PhysioNet/CinC challenge 2013. The final results indicate that the algorithm is able to detect fetal peaks for a variety of signals with different morphologies and strength levels encountered in clinical practice. PMID:25069479
Duration of Purkinje cell complex spikes increases with their firing frequency
Warnaar, Pascal; Couto, Joao; Negrello, Mario; Junker, Marc; Smilgin, Aleksandra; Ignashchenkova, Alla; Giugliano, Michele; Thier, Peter; De Schutter, Erik
Climbing fiber (CF) triggered complex spikes (CS) are massive depolarization bursts in the cerebellar Purkinje cell (PC), showing several high frequency spikelet components (▒600 Hz). Since its early observations, the CS is known to vary in shape. In this study we describe CS waveforms, extracellularly recorded in awake primates (Macaca mulatta) performing saccades. Every PC analyzed showed a range of CS shapes with profoundly different duration and number of spikelets. The initial part of the CS was rather constant but the later part differed greatly, with a pronounced jitter of the last spikelets causing a large variation in total CS duration. Waveforms did not effect the following pause duration in the simple spike (SS) train, nor were SS firing rates predictive of the waveform shapes or vice versa. The waveforms did not differ between experimental conditions nor was there a preferred sequential order of CS shapes throughout the recordings. Instead, part of their variability, the timing jitter of the CSÆs last spikelets, strongly correlated with interval length to the preceding CS: shorter CS intervals resulted in later appearance of the last spikelets in the CS burst, and vice versa. A similar phenomenon was observed in rat PCs recorded in vitro upon repeated extracellular stimulation of CFs at different frequencies in slice experiments. All together these results strongly suggest that the variability in the timing of the last spikelet is due to CS frequency dependent changes in PC excitability. PMID:25918500
Month-to-month and year-to-year reproducibility of high frequency QRS ECG signals
NASA Technical Reports Server (NTRS)
Batdorf, Niles J.; Feiveson, Alan H.; Schlegel, Todd T.
High frequency electrocardiography analyzing the entire QRS complex in the frequency range of 150 to 250 Hz may prove useful in the detection of coronary artery disease, yet the long-term stability of these waveforms has not been fully characterized. Therefore, we prospectively investigated the reproducibility of the root mean squared voltage, kurtosis, and the presence versus absence of reduced amplitude zones in signal averaged 12-lead high frequency QRS recordings acquired in the supine position one month apart in 16 subjects and one year apart in 27 subjects. Reproducibility of root mean squared voltage and kurtosis was excellent over these time intervals in the limb leads, and acceptable in the precordial leads using both the V-lead and CR-lead derivations. The relative error of root mean squared voltage was 12% month-to-month and 16% year-to-year in the serial recordings when averaged over all 12 leads. Reduced amplitude zones were also reproducible up to a rate of 87% and 81%, respectively, for the month-to-month and year-to-year recordings. We conclude that 12-lead high frequency QRS electrocardiograms are sufficiently reproducible for clinical use.
Low power adder based digital filter for QRS detector.
Murali, L; Chitra, D; Manigandan, T
Most of the Biomedical applications use dedicated processors for the implementation of complex signal processing. Among them, sensor network is also a type, which has the constraint of low power consumption. Since the processing elements are the most copiously used operations in the signal processors, the power consumption of this has the major impact on the system level application. In this paper, we introduce low power concept of transistor stacking to reduce leakage power; and new architectures based on stacking to implement the full adder and its significance at the digital filter level for QRS detector are implemented. The proposed concept has lesser leakage power at the adder as well as filter level with trade-off in other quality metrics of the design. This enabled the design to be dealt with as the low-power corner and can be made adaptable to any level of hierarchical abstractions as per the requirement of the application. The proposed architectures are designed, modeled at RTL level using the Verilog-HDL, and synthesized in Synopsys Design Compiler by mapping the design to 65 nm technology library standard cells. PMID:24895649
Low Power Adder Based Digital Filter for QRS Detector
Murali, L.; Chitra, D.; Manigandan, T.
Most of the Biomedical applications use dedicated processors for the implementation of complex signal processing. Among them, sensor network is also a type, which has the constraint of low power consumption. Since the processing elements are the most copiously used operations in the signal processors, the power consumption of this has the major impact on the system level application. In this paper, we introduce low power concept of transistor stacking to reduce leakage power; and new architectures based on stacking to implement the full adder and its significance at the digital filter level for QRS detector are implemented. The proposed concept has lesser leakage power at the adder as well as filter level with trade-off in other quality metrics of the design. This enabled the design to be dealt with as the low-power corner and can be made adaptable to any level of hierarchical abstractions as per the requirement of the application. The proposed architectures are designed, modeled at RTL level using the Verilog-HDL, and synthesized in Synopsys Design Compiler by mapping the design to 65?nm technology library standard cells. PMID:24895649
QRS Fragmentation and Sudden Cardiac Death in the Obese and Overweight
Narayanan, Kumar; Zhang, Lin; Kim, Candice; Uy?Evanado, Audrey; Teodorescu, Carmen; Reinier, Kyndaron; Zheng, Zhi?Jie; Gunson, Karen; Jui, Jonathan; Chugh, Sumeet S.
Background Obesity has been associated with significantly greater risk of sudden cardiac death (SCD); however, identifying the obese patient at highest risk remains a challenge. We evaluated the association between QRS fragmentation on the 12?lead electrocardiogram and SCD, in obese/overweight subjects. Methods and Results In the ongoing prospective, community?based Oregon Sudden Unexpected Death Study (population approximately 1 million), we performed a case?control analysis, comparing obese/overweight SCD victims with obese/overweight controls from the same geographic region. Archived ECGs prior and unrelated to the SCD event were used for cases and all ECG measurements were assessed in blinded fashion. Fragmentation was defined as the presence of RSRÆ patterns and/or notching of the R/S wave in at least 2 contiguous leads. Analysis was limited to ECGs with QRS duration <120 ms. Overall prevalence of fragmentation was higher in cases (n=185; 64.9▒13.8 years; 67.0% male) compared with controls (n=405; 64.9▒11.0 years; 64.7% male) (34.6% versus 26.9%, P=0.06). Lateral fragmentation was significantly more frequent in cases (8.1% versus 2.5%; P<0. 01), with non?significant differences in anterior and inferior territories. Fragmentation in multiple territories (?2) was also more likely to be observed in cases (9.7% versus 4.9%, P=0.02). In multivariable analysis with consideration of established SCD risk factors, lateral fragmentation was significantly associated with SCD (OR 2.84; 95% CI 1.01 to 8.02; P=0.05). Conclusion QRS fragmentation, especially in the lateral territory is a potential risk marker for SCD independent of the ejection fraction, among obese/overweight subjects in the general population. PMID:25762804
Body sensor network based context aware QRS detection.
Li, Huaming; Tan, Jindong
In this paper, a body sensor network (BSN) based context aware QRS detection scheme is proposed. The algorithm uses the context information provided by the body sensor network to improve the QRS detection performance by dynamically selecting the leads with best SNR and taking advantage of the best features of two complementary detection algorithms. The accelerometer data from the BSN are used to classify the patients' daily activity and provide the context information. The classification results indicate both the type of the activities and their corresponding intensity, which is related to the signal/noise ratio of the ECG recordings. Activity intensity is first fed to lead selector to eliminate the leads with low SNR, and then is fed to a selector for selecting a proper QRS detector according to the noise level. MIT-BIH noise stress test database is used to evaluate the algorithms. PMID:17946171
Age and sex dependent criteria for lower limits of QRS voltages
E. Clark; B. Devine; P. W. Macfarlane
The aim of this study was to examine whether criteria for low QRS voltage should be age and sex dependent. A database of 1496 normal ECGs from healthy adults was analysed using the University of Glasgow ECG analysis program. Correlation coefficients between peak- to-peak QRS voltages (ppQRS) and age were obtained. Differences in ppQRS due to sex were measured statistically.
Complex structure of electrophysiological gradients emerging during long-duration ventricular fibrillation in the canine heart
Venable, Paul W.; Taylor, Tyson G.; Shibayama, Junko; Warren, Mark
Long-duration ventricular fibrillation (LDVF) in the globally ischemic heart is a common setting of cardiac arrest. Electrical heterogeneities during LDVF may affect outcomes of defibrillation and resuscitation. Previous studies in large mammalian hearts have investigated the role of Purkinje fibers and electrophysiological gradients between the endocardium (Endo) and epicardium (Epi). Much less is known about gradients between the right ventricle (RV) and left ventricle (LV) and within each chamber during LDVF. We studied the transmural distribution of the VF activation rate (VFR) in the RV and LV and at the junction of RV, LV, and septum (Sep) during LDVF using plunge needle electrodes in opened-chest dogs. We also used optical mapping to analyze the Epi distribution of VFR, action potential duration (APD), and diastolic interval (DI) during LDVF in the RV and LV of isolated hearts. Transmural VFR gradients developed in both the RV and LV, with a faster VFR in Endo. Concurrently, large VFR gradients developed in Epi, with the fastest VFR in the RV-Sep junction, intermediate in the RV, and slowest in the LV. Optical mapping revealed a progressively increasing VFR dispersion within both the LV and RV, with a mosaic presence of fully inexcitable areas after 4¢8 min of LDVF. The transmural, interchamber, and intrachamber VFR heterogeneities were of similar magnitude. In both chambers, the inverse of VFR was highly correlated with DI, but not APD, at all time points of LDVF. We conclude that the complex VFR gradients during LDVF in the canine heart cannot be explained solely by the distribution of Purkinje fibers and are related to regional differences in the electrical depression secondary to LDVF. PMID:20802138
Real Time QRS Detection Based on M-ary Likelihood Ratio Test on the DFT Coefficients
G¾rriz, Juan Manuel; RamĒrez, Javier; Olivares, Alberto; Padilla, Pablo; Puntonet, Carlos G.; Cant¾n, Manuel; Laguna, Pablo
This paper shows an adaptive statistical test for QRS detection of electrocardiography (ECG) signals. The method is based on a M-ary generalized likelihood ratio test (LRT) defined over a multiple observation window in the Fourier domain. The motivations for proposing another detection algorithm based on maximum a posteriori (MAP) estimation are found in the high complexity of the signal model proposed in previous approaches which i) makes them computationally unfeasible or not intended for real time applications such as intensive care monitoring and (ii) in which the parameter selection conditions the overall performance. In this sense, we propose an alternative model based on the independent Gaussian properties of the Discrete Fourier Transform (DFT) coefficients, which allows to define a simplified MAP probability function. In addition, the proposed approach defines an adaptive MAP statistical test in which a global hypothesis is defined on particular hypotheses of the multiple observation window. In this sense, the observation interval is modeled as a discontinuous transmission discrete-time stochastic process avoiding the inclusion of parameters that constraint the morphology of the QRS complexes. PMID:25356628
Variation in canopy duration in the perennial biofuel crop Miscanthus reveals complex associations with yield.
Robson, Paul R H; Farrar, Kerrie; Gay, Alan P; Jensen, Elaine F; Clifton-Brown, John C; Donnison, Iain S
Energy crops can provide a sustainable source of power and fuels, and mitigate the negative effects of CO2 emissions associated with fossil fuel use. Miscanthus is a perennial C4 energy crop capable of producing large biomass yields whilst requiring low levels of input. Miscanthus is largely unimproved and therefore there could be significant opportunities to increase yield. Further increases in yield will improve the economics, energy balance, and carbon mitigation of the crop, as well as reducing land-take. One strategy to increase yield in Miscanthus is to maximize the light captured through an extension of canopy duration. In this study, canopy duration was compared among a diverse collection of 244 Miscanthus genotypes. Canopy duration was determined by calculating the number of days between canopy establishment and senescence. Yield was positively correlated with canopy duration. Earlier establishment and later senescence were also both separately correlated with higher yield. However, although genotypes with short canopy durations were low yielding, not all genotypes with long canopy durations were high yielding. Differences of yield between genotypes with long canopy durations were associated with variation in stem and leaf traits. Different methodologies to assess canopy duration traits were investigated, including visual assessment, image analysis, light interception, and different trait thresholds. The highest correlation coefficients were associated with later assessments of traits and the use of quantum sensors for canopy establishment. A model for trait optimization to enable yield improvement in Miscanthus and other bioenergy crops is discussed. PMID:23599277
The complex duration perception of emotional faces: effects of face direction
Kliegl, Katrin M.; Limbrecht-Ecklundt, Kerstin; D³rr, Lea; Traue, Harald C.; Huckauf, Anke
The perceived duration of emotional face stimuli strongly depends on the expressed emotion. But, emotional faces also differ regarding a number of other features like gaze, face direction, or sex. Usually, these features have been controlled by only using pictures of female models with straight gaze and face direction. Doi and Shinohara (2009) reported that an overestimation of angry faces could only be found when the modelÆs gaze was oriented toward the observer. We aimed at replicating this effect for face direction. Moreover, we explored the effect of face direction on the duration perception sad faces. Controlling for the sex of the face model and the participant, female and male participants rated the duration of neutral, angry, and sad face stimuli of both sexes photographed from different perspectives in a bisection task. In line with current findings, we report a significant overestimation of angry compared to neutral face stimuli that was modulated by face direction. Moreover, the perceived duration of sad face stimuli did not differ from that of neutral faces and was not influenced by face direction. Furthermore, we found that faces of the opposite sex appeared to last longer than those of the same sex. This outcome is discussed with regards to stimulus parameters like the induced arousal, social relevance, and an evolutionary context. PMID:25852589
QRS complex abnormalities in subjects with idiopathic ventricular fibrillation
Konstantinos P. Letsas; Reinhold Weber; Dietrich Kalusche; Thomas Arentz
Recent data point to a high incidence of early repolarization abnormalities among patients with idiopathic ventricular fibrillation (IVF). ECG data from 11 patients with idiopathic IVF were evaluated for the presence of initial (slurring or notching of the ascending limb of the R-wave that resembles a ōpseudoö delta-wave) and terminal (slurring or notching of the descending limb of the R-wave
Pulse pressure and QRS width evaluation as an inexpensive tool for heart failure assessment.
Beck-da-Silva, LuĒs; Goldraich, LĒvia; Bonzanini, LaĒsa; Rossi, Gabriela; Nuernberg, Gabriela; Camey, Suzi A; Rohde, LuĒs Eduardo; Clausell, Nadine
Decreased pulse pressure (PP) is associated with low cardiac output and increased mortality in heart failure (HF) inpatients. QRS width is a well-known prognostic factor in HF. The study purpose was to explore the mortality effect of combining PP and QRS width in HF outpatients. Initial sphygmomanometrically determined PP and QRS width on the first electrocardiograph in 327 consecutive patients at an HF clinic were recorded. According to PP > or = or <40 mm Hg and QRS width > or = or <120 ms, patients were classified into 4 groups. Study groups were analyzed for their effect on mortality using Cox proportional hazards regression analysis. Patients with PP <40 mm Hg had higher mortality (59% vs 45%; P=.015). QRS width > or =120 ms indicated a trend toward higher mortality (57% vs 48%; P=.067). Actuarial survival curves showed that group 4 (QRS width > or =120 ms and PP <40 mm Hg) had significant increased mortality risk in 3.5 years' mean follow-up. Group 4 had a mean survival time of 1124 days (SD=124) vs 2233 days (SD=285) in group 1 (QRS width <120 ms and PP > or =40 mm Hg) (P=.022). There was a linear association between left ventricular ejection fraction (LVEF) and study groups. PP and QRS width are readily available, inexpensive, and relevant clinical measures to help identify HF outpatients with significantly worse prognosis and decreased LVEF. PMID:19751423
Atlantis Time-Lapse Move to KSC Visitor Complex - Duration: 3 minutes, 21 seconds.
Time-lapse cameras captured space shuttle Atlantis making a 10-mile trek from the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida to the Kennedy Space Center Visitor Complex whe...
Correlation between fragmented QRS and the short-term prognosis of patients with acute myocardial infarction*
Sheng, Qin-hui; Hsu, Chih-Chi; Li, Jian-ping; Hong, Tao; Huo, Yong
This study is aimed to investigate the clinical significance and the short-term prognostic value of fragmented QRS (fQRS) for patients with acute myocardial infarction (AMI). Three hundred patients with AMI were tested with retrospective analysis on the patientsÆ clinical information, hospitalized treatment, fQRS onset time, location of lesions, and other relevant data, in order to assess the relationship between the presence of fQRS and its prognosis. The rates of malignant cardiac arrhythmia, left ventricular systolic dysfunction (LVSD), and mortality in the positive fQRS group were 13.6%, 29.2%, and 23.7%, respectively, with all showing a p value <0.05. For the ST segment elevation myocardial infarction (STEMI) subgroup, all the rates showed significant differences with a p value <0.01, while for the non-STEMI (NSTEMI) subgroup showed no significant differences. In patients with a positive fQRS, there were no differences in malignant cardiac arrhythmia between patients with and without percutaneous coronary intervention (PCI) (p>0.05). As for the LVSD and mortality, the p values between patients with and without PCI were 0.031 and 0.000, respectively, suggesting statistical significance. The results imply that AMI patients with positive fQRS especially for the patients with STEMI had higher rates of malignant cardiac arrhythmia, LVSD, and mortality than the non-fQRS group. Patients of AMI with positive fQRS, who underwent early revascularization, could lower the incidence of the cardiovascular event. In addition, the presence of fQRS could be used as an indication of early intervention treatment for patients. PMID:24390746
Re-entrant tachycardia using two bypass tracts and excluding AV node in short PR interval, normal QRS syndrome.
Ward, D E; Camm, A J; Spurrell, R A
In patients with the short PR interval, normal QRS complex syndrome, paroxysmal tachycardias are usually the result of circus movement involving the AV node and a partial or complete AV nodal bypass. We report 2 patients with this syndrome who suffered distressing rapid paroxysms of tachycardia but in whom there was evidence of a concealed direct VA connection. In both patients, tachycardia was initiated with critical AV prolongation distal to the His bundle, in response to programmed atrial premature stimuli. The constancy of the timing of the atrial echo from the onset of the QRS complex in the presence of a varying HV interval is evidence for involvement of the ventricles in the re-entry pathway. In addition, in both patients the appearance of left bundle-branch block during tachycardia was associated with appropriate prolongation of tachycardia cycle length consistent with the presence of a direct VA connection. The short AH interval during tachycardia and the absence of critical AH prolongation suggests the participation of a rapidly conducting pathway in the anterograde limb of the tachycardia circuit. PMID:708514
Does a Sodium-Free Buffer Affect QRS Width in Experimental Amitriptyline Overdose?
C. Keith Stone; Carl M Kraemer; Robert Carroll; Ron Low
Study objectives: We carried out this study to determine the effects of pH alteration on QRS width with administration of tromethamine, a non-sodium-containing buffering agent, in experimental amitriptyline overdose. Design: Prospective, nonblinded trial. Participants: Adult mongrel dogs. Interventions: Pentobarbital-anesthetized dogs were overdosed with amitriptyline 5 mg\\/kg followed by infusion at 1.0 mg\\/kg\\/minute until the QRS width doubled, then decreased to
QRS mapping in the evaluation of acute anterior myocardial infarction.
von Essen, R; Merx, W; Doerr, R; Effert, S; Silny, J; Rau, G
In 42 patients with acute anterior myocardial infarction (AMI), we studied the course of Q-wave development and R-wave reduction during the first 48 hours after the onset of chest pain. We used precordial mapping in relation to clinical features, hemodynamic measurements and enzyme release. Q waves developed within 6-14 hours (mean 9 hours) after onset of symptoms. R-wave amplitudes demonstrated nearly a reflected image: They reduced abruptly 5-11 hours (mean 9 hours) after onset of chest pain, coinciding with ST-segment elevation. In 14 patients (group A, 33%) after initial QRS alterations, there were no further changes. Twenty patients (group B, 48%) had a distinct new increase of Q waves (delta sigma Q = 3.0 +/- 2.0 mV/hours) and further R-wave reduction (-delta sigma R = 1.0 +/- 0.6 mV/hour) simultaneous with new severe chest pain and a delayed second increase of enzyme release corresponding with extension of infarction. There were no significant differences between the groups in age, hemodynamics and infarct size calculated from creatine kinase release. Eight patients (group C, 19%) had contradictory findings. Our findings are consistent with previous results indicating that the critical period for intervention is very small except in patients with extension of necrosis. PMID:7397969
Etanercept Induces Low QRS Voltage and Autonomic Dysfunction in Mice with Experimental Chagas Disease
RodrĒguez-Angulo, Hķctor; GarcĒa, Oscar; Castillo, Endher; Cardenas, Edward; Marques, Juan; Mijares, Alfredo
Background Chagas disease is a tropical parasitic disease caused by the flagellate protozoan Trypanosoma cruzi. Chagasic cardiomyopathy is characterized by disorders of autonomic regulation and action potential conduction in the acute and chronic phases of infection. Although tumor necrosis factor alpha (TNF-?) has been linked to cardiomyopathy in experimental models and in patients with Chagas disease, other reports suggest that TNF-? may exert anti-parasitic actions during the acute phase of infection. Objectives This study aimed to determine the effects of a soluble TNF-? blocker, etanercept, on electrocardiographic parameters in the acute phase of experimental infection with Trypanosoma cruzi. Methods Electrocardiograms were obtained from untreated infected mice and infected mice who were treated with etanercept 7 days after infection. ECG wave and heart rate variability parameters were determined using Chart for Windows. Results Etanercept treatment resulted in a low QRS voltage and decreased heart rate variability compared with no treatment. However, the treated mice exhibited a delay in the fall of the survival curve during the acute phase. Conclusion The results of this study suggest that although etanercept treatment promotes survival in mice infected with a virulent T. cruzi strain, TNF-? blockade generates a low voltage complex and autonomic dysfunction during the acute phase of infection. These findings indicate that mortality during the acute phase can be attributed to a systemic inflammatory response rather than cardiac dysfunction. PMID:23877744
Online digital filter and QRS detector applicable in low resource ECG monitoring systems.
Tabakov, Serafim; Iliev, Ivo; Krasteva, Vessela
The present work describes fast computation methods for real-time digital filtration and QRS detection, both applicable in autonomous personal ECG systems for long-term monitoring. Since such devices work under considerable artifacts of intensive body and electrode movements, the input filtering should provide high-quality ECG signals supporting the accurate ECG interpretation. In this respect, we propose a combined high-pass and power-line interference rejection filter, introducing the simple principle of averaging of samples with a predefined distance between them. In our implementation (sampling frequency of 250 Hz), we applied averaging over 17 samples distanced by 10 samples (Filter10x17), thus realizing a comb filter with a zero at 50 Hz and high-pass cut-off at 1.1 Hz. Filter10x17 affords very fast filtering procedure at the price of minimal computing resources. Another benefit concerns the small ECG distortions introduced by the filter, providing its powerful application in the preprocessing module of diagnostic systems analyzing the ECG morphology. Filter10x17 does not attenuate the QRS amplitude, or introduce significant ST-segment elevation/depression. The filter output produces a constant error, leading to uniform shifting of the entire P-QRS-T segment toward about 5% of the R-peak amplitude. Tests with standardized ECG signals proved that Filter10x17 is capable to remove very strong baseline wanderings, and to fully suppress 50 Hz interferences. By changing the number of the averaged samples and the distance between them, a filter design with different cut-off and zero frequency could be easily achieved. The real-time QRS detector is designed with simplified computations over single channel, low-resolution ECGs. It relies on simple evaluations of amplitudes and slopes, including history of their mean values estimated over the preceding beats, smart adjustable thresholds, as well as linear logical rules for identification of the R-peaks in real-time. The performance of the QRS detector was tested with internationally recognized ECG databases (AHA, MIT-BIH, European ST-T database), showing mean sensitivity of 99.65% and positive predictive value of 99.57%. The performance of the presented QRS detector can be highly rated, comparable and even better than other published real-time QRS detectors. Examples representing some typical unfavorable conditions in real ECGs, illustrate the common operation of Filter10x17 and the QRS detector. PMID:18752068
Fetal QRS detection and heart rate estimation: a wavelet-based approach.
Almeida, Rute; Gonńalves, HernŌni; Bernardes, JoŃo; Rocha, Ana Paula
Fetal heart rate monitoring is used for pregnancy surveillance in obstetric units all over the world but in spite of recent advances in analysis methods, there are still inherent technical limitations that bound its contribution to the improvement of perinatal indicators. In this work, a previously published wavelet transform based QRS detector, validated over standard electrocardiogram (ECG) databases, is adapted to fetal QRS detection over abdominal fetal ECG. Maternal ECG waves were first located using the original detector and afterwards a version with parameters adapted for fetal physiology was applied to detect fetal QRS, excluding signal singularities associated with maternal heartbeats. Single lead (SL) based marks were combined in a single annotator with post processing rules (SLR) from which fetal RR and fetal heart rate (FHR) measures can be computed. Data from PhysioNet with reference fetal QRS locations was considered for validation, with SLR outperforming SL including ICA based detections. The error in estimated FHR using SLR was lower than 20Ābpm for more than 80% of the processed files. The median error in 1Āmin based FHR estimation was 0.13Ābpm, with a correlation between reference and estimated FHR of 0.48, which increased to 0.73 when considering only records for which estimated FHRĀ>Ā110Ābpm. This allows us to conclude that the proposed methodology is able to provide a clinically useful estimation of the FHR. PMID:25070210
An algorithm for QRS onset and offset detection in single lead electrocardiogram records.
Manriquez, Alfredo Illanes; Zhang, Qinghua
In this paper a new algorithm is proposed for QRS onset and offset detection in single lead electrocardiogram (ECG) records. In each cardiac cycle, the R peak is first detected to serve as a reference to delimit the search windows for the QRS onset and offset. Then, an auxiliary signal is defined from the envelope of the ECG signal. Finally, a statistical hypothesis test is applied to the auxiliary signal in order to detect mean changes. The performances of the algorithm have been evaluated using the PhysioNet QT database. The mean and standard deviation of the differences between onsets or offsets manually marked by cardiologists and those detected by the proposed algorithm are computed. The standard deviations obtained in this work are around the tolerances accepted by expert physicians, and slightly outperform the results obtained by the other known algorithms evaluated with the same database. PMID:18002013
Reducing motion artifacts for robust QRS detection in capacitive sensor arrays
Aline Serteyn; Xintan Lin; Oliver Amft
Non-contact capacitive ECG measurements (cECG) have applications in various unobtrusive and ubiquitous systems. However, cECG signals are frequently corrupted by interference and motion artifacts. In this work array processing methods, such as blind source separation, were used to reduce the impact of motion artifacts on QRS detection. The capacitive sensor array was integrated in a bed mattress and covered with
Reappearance of anterior QRS forces after coronary bypass surgery. An electrovectorcardiographic study.
Zeft, H J; Friedberg, H D; King, J F; Manley, J C; Huston, J H; Johnson, W D
This report describes the reappearance of anterior QRS electrical forces in six patients after direct coronary arterial bypass surgery. Each patient had severe coronary artery disease including a segmental stenosis of the left anterior descending artery. Revascularization was performed by direct anastomosis of the left mammary artery to the left anterior descending coronary artery and saphenous vein bypass of other stenotic coronary arteries. Preoperative electrocardiograms and vectorcardiograms showed patterns of anterior wall myocardial infarction with absent or diminutive anterior QRS forces. In each case, postoperative studies demonstrated the regeneration of anterior QRS forces within 10 days of operation. Although these patients represent a small percent of those with a preoperative pattern of infarction who undergo coronary revascularization, the findings demonstrate that electrically silent areas of myocardium may be altered and are not always synonymous with myocardial cell death. Chronic myocardial ischemia may in certain instances produce electrocardiographic and vectorcardiographic patterns of myocardial infarction that may be reversible upon reestablishment of perfusion to ischemic areas. PMID:1080350
QRS fragmentation in patients with arrhythmogenic right ventricular cardiomyopathy and complete right bundle branch block: a risk stratification
Background: Patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) and complete right bundle branch block (RBBB) very often have recurrent ventricular tachycardia and develop biventricular heart failure in the follow up, requiring heart transplantation and/or diuretics. In other patients with ARVC/D excluding RBBB, QRS fragmentation in the S wave of right precordial leads identifies patients with recurrent ventricular tachycardia, primary ventricular fibrillation, and recurrent implantable cardioverter defibrillator discharges; QRS fragmentation ?3 leads characterized patients who died from sudden cardiac death. Method: In a cohort of 374 patients with ARVC/D (208 males; mean▒SD age 46.5▒14.8 years), there were 22 patients with complete RBBB: 17 patients with ARVD/C developed complete RBBB and had biventricular heart failure in a follow up of 4¢6 years. In five patients with ARVC/D, complete RBBB was initially evident. In all patients with ARVC/D and RBBB, QRS fragmentation ?3 of all 12 ECG leads and QRS fragmentation in the S wave of right precordial leads were analysed. Results: QRS fragmentation ?3 of all 12 ECG leads and in the S wave of right precordial leads were present in 16/17 patients who developed RBBB and none of the five patients with initial RBBB. In one patient with initial RBBB, QRS fragmentation ?3 leads was present (r=17.45; p<0.0001). Conclusion: Patients with recurrent ventricular tachycardia who develop biventricular heart failure requiring heart transplantation and/or diuretics are characterized by QRS fragmentation in the S wave of right precordial leads and ?3 of all 12 ECG leads. These results are statistically significant. Patients with initial RBBB have an overall benign prognosis. PMID:24062912
Association of the Frontal QRS-T Angle with Adverse Cardiac Remodeling, Impaired Left and Right Ventricular Function, and Worse Outcomes in Heart Failure with Preserved Ejection Fraction
Selvaraj, Senthil; Ilkhanoff, Leonard; Burke, Michael A.; Freed, Benjamin H.; Lang, Roberto M.; Martinez, Eva E.; Shah, Sanjiv J.
Background No prior studies have investigated the association of QRS-T angle with cardiac structure/function and outcomes in heart failure with preserved ejection fraction (HFpEF). We hypothesized that increased frontal QRS-T angle is associated with worse cardiac function/remodeling and adverse outcomes in HFpEF. Methods We prospectively studied 376 patients with HFpEF (i.e. symptomatic HF with left ventricular [LV] ejection fraction >50%.) The frontal QRS-T angle was calculated from the 12-lead electrocardiogram. Patients were divided into tertiles by frontal QRS-T angle (0¢26░, 27¢75░, and 76¢179░), and clinical, laboratory, and echocardiographic data were compared among groups. Cox proportional hazards analyses were performed to determine the association between QRS-T angle and outcomes. Results The mean age of the cohort was 64▒13 years, 65% were women, and the mean QRS-T angle was 61▒51░. Patients with increased QRS-T angle were older, had a lower body-mass index, more frequently had coronary artery disease, diabetes, chronic kidney disease, and atrial fibrillation, and had higher B-type natriuretic peptide (BNP) levels (P<0.05 for all comparisons). After multivariable adjustment, patients with increased QRS-T angle had higher BNP levels in addition to higher LV mass index, worse diastolic function parameters, more right ventricular (RV) remodeling, and worse RV systolic function (P<0.05 for all associations). QRS-T angle was independently associated with the composite outcome of cardiovascular hospitalization or death on multivariable analysis, even after adjusting for BNP (HR for the highest QRS-T tertile = 2.0, 95% CI 1.2¢3.4; P=0.008). Conclusions In HFpEF, increased QRS-T angle is independently associated with worse left and right ventricular function/remodeling and adverse outcomes. PMID:24075945
Influence of crude protein content, ingredient complexity, feed form, and duration of feeding of the Phase I diets on productive performance and nutrient digestibility of Iberian pigs.
Berrocoso, J D; Salda±a, B; Serrano, M P; Cßmara, L; Ibß±ez, M A; Mateos, G G
The influence of CP content and ingredient complexity, feed form, and duration of feeding of the Phase I diets on growth performance and total tract apparent digestibility (TTAD) of energy and nutrients was studied in Iberian pigs weaned at 28 d of age. There were 12 dietary treatments with 2 type of feeds (high-quality, HQ; and low-quality, LQ), 2 feed forms (pellets vs. mash), and 3 durations (7, 14, and 21 d) of supply of the Phase I diets. From d 7, 14, or 21 (depending on treatment) to d 35, all pigs received a common diet in mash form. Each treatment was replicated 3 times (6 pigs/pen). For the entire experiment, ADG (P < 0.05) and ADFI (P < 0.01) were less with the HQ than the LQ Phase I diets, but G:F was not affected. Pelleting of the Phase I diets did not affect ADG but improved G:F (P < 0.01). Feeding the Phase I diets from d 0 to 21 improved G:F (P < 0.05) but decreased ADG (P < 0.01) as compared with 7 or 14 d of feeding. Postweaning diarrhea (PWD) tended to be greater (P = 0.06) for pigs fed the HQ diets than pigs fed the LQ diets and pigs fed pellets than those fed mash (P < 0.001). Also, PWD was greater for pigs fed the Phase I diet for 14 or 21 d than those fed the diet for 7 d (P < 0.01). From d 0 to 21, ADG and G:F were not affected (P > 0.10) by feed quality, but feeding pellets or increasing the duration of feeding the Phase I diets improved G:F (P < 0.01). Also, in this period, PWD was greater with pellets than with mash and for pigs fed the Phase I diets for 14 or 21 d than for pigs fed the diet for only 7 d (P < 0.01). From d 21 to 35, pigs previously fed the LQ diet had greater ADG than pigs fed the HQ Phase I diets (P < 0.001). Also, pigs fed the Phase I diets for 21 d had decreased ADG (P < 0.05) and ADFI (P < 0.001) and reduced G:F (P < 0.05) than pigs fed these diets for 7 or 14 d. Organic matter digestibility was greater for pigs fed the HQ Phase I diets than pigs fed the LQ Phase I diets (P < 0.05). Pelleting improved TTAD of all nutrients (P < 0.01). It is concluded that HQ Phase I diets increased TTAD of nutrients but not feed efficiency of Iberian pigs from d 0 to 35. Also, pelleting improved energy and nutrient digestibility and feed efficiency. Increasing the duration of supply of the Phase I diets from 7 to 21 d improved feed efficiency but reduced ADG. Therefore, the use of LQ Phase I diets in pellet form for no more than 7 d after weaning is recommended in Iberian pigs. PMID:23307842
Long-term effectiveness of cardiac resynchronization therapy in patients with refractory heart failure and ōnarrowö QRS
Augusto Achilli; Massimo Sassara; Sabina Ficili; Daniele Pontillo; Paola Achilli; Claudio Alessi; Stefano De Spirito; Roberto Guerra; Nicolino Patruno; Francesco Serra
ObjectivesThe aim of the study was to evaluate the effectiveness of cardiac resynchronization therapy (CRT) in patients with refractory heart failure (HF) and incomplete left bundle branch block (ōnarrowö QRS), together with echocardiographic evidence of interventricular and intraventricular asynchrony.
Electrocradiographic Qrs Axis, Q Wave and T-wave Changes in 2nd and 3rd Trimester of Normal Pregnancy
S., Chandrasekharappa; Brid, S.V
Background: Pregnancy although a physiological phenomena affects all the functions of the maternal body and brings about remarkable changes in the cardiovascular system. The cardiovascular changes and many of the physiological adaptations of normal pregnancy alter the physical findings thus, sometimes misleading the diagnosis of heart disease. Pregnancy also brings about various changes in the electrocardiogram, further confusing with that of heart disease. This study is undertaken to highlight the effect of normal pregnancy on the QRS axis, Q wave and T-wave of the Electrocardiogram and thereby helps us to distinguish it from that of pathological changes. Objectives: To study the effect of normal pregnancy on the QRS axis, Q wave and T-wave in the electrocardiogram and to compare with that of normal non pregnant women. Materials and Methods: Fifty normal pregnant women in 2nd and 3rd trimester each between 20¢ 35 y of age and 50 normal non pregnant women of the same age group were selected for the study. A 12 lead ECG was recorded by using ECG machine with special emphasis on QRS axis, Q wave and T-wave changes and all the parameters were analysed. Results: The ECG changes observed in our study include, deviation of QRS axis towards left as pregnancy advanced, significant increased incidence of occurrence of prominent Q waves in lead II, III and avF in pregnant group (p < 0.05 ) and, T-wave abnormalities like flat and inverted T-waves in lead III, V1 ¢ V3 were more frequent in pregnant group ( p<0.05 ) than in non pregnant group. Conclusion:Normal pregnancy brings about various changes in ECG. These changes during pregnancy should be interpretated with caution by the physicians. It is necessary to understand the normal physiological changes which in turn help us in better management of those with cardiac disease. PMID:25386425
Duration tuning across vertebrates.
Aubie, Brandon; Sayegh, Riziq; Faure, Paul A
Signal duration is important for identifying sound sources and determining signal meaning. Duration-tuned neurons (DTNs) respond preferentially to a range of stimulus durations and maximally to a best duration (BD). Duration-tuned neurons are found in the auditory midbrain of many vertebrates, although studied most extensively in bats. Studies of DTNs across vertebrates have identified cells with BDs and temporal response bandwidths that mirror the range of species-specific vocalizations. Neural tuning to stimulus duration appears to be universal among hearing vertebrates. Herein, we test the hypothesis that neural mechanisms underlying duration selectivity may be similar across vertebrates. We instantiated theoretical mechanisms of duration tuning in computational models to systematically explore the roles of excitatory and inhibitory receptor strengths, input latencies, and membrane time constant on duration tuning response profiles. We demonstrate that models of duration tuning with similar neural circuitry can be tuned with species-specific parameters to reproduce the responses of in vivo DTNs from the auditory midbrain. To relate and validate model output to in vivo responses, we collected electrophysiological data from the inferior colliculus of the awake big brown bat, Eptesicus fuscus, and present similar in vivo data from the published literature on DTNs in rats, mice, and frogs. Our results support the hypothesis that neural mechanisms of duration tuning may be shared across vertebrates despite species-specific differences in duration selectivity. Finally, we discuss how the underlying mechanisms of duration selectivity relate to other auditory feature detectors arising from the interaction of neural excitation and inhibition. PMID:22553042
Importance of preexcited QRS morphology during induced atrial fibrillation to the diagnosis and localization of multiple accessory pathways.
Fananapazir, L; German, L D; Gallagher, J J; Lowe, J E; Prystowsky, E N
The present investigation evaluates the ability of several electrocardiographic (ECG) and electrophysiologic methods to identify multiple accessory pathways in 47 patients in whom the presence and sites of multiple accessory pathways were confirmed intraoperatively. To establish ECG features that suggested the presence of multiple accessory pathways in these patients, we initially studied the 12-lead ECG during maximal preexcitation in 101 patients with single accessory pathways. Distinctive 12-lead ECG patterns were noted for six defined anatomic areas around the right and left atrioventricular groove. Multiple preexcited QRS morphologies, each typical for a separate accessory pathway, and atypical preexcited QRS morphologies were recorded during atrial fibrillation in 31 of 47 (66%) patients with multiple accessory pathways. By comparison, the ECG during sinus rhythm and rapid atrial pacing identified 14 (32%) and 26 (55%) of the patients, respectively. In 12 (26%) patients in whom evidence for multiple accessory pathways was absent from endocardial mapping data, atrial fibrillation provided the diagnosis. In five (11%) patients, atrial fibrillation was the only method that demonstrated the presence of multiple accessory pathways. A combination of ECG findings during atrial fibrillation and rapid atrial pacing plus endocardial mapping data identified 43 (91%) of the patients with multiple accessory pathways. There were two unique fusion patterns on the 12-lead ECG that were characteristic of specific multiple accessory pathway combinations.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2297863
Implications of Franciscan Complex graywacke geochemistry for sediment transport, provenance determination, burial-exposure duration, and fluid exchange with cosubducted metabasites
NASA Astrophysics Data System (ADS)
Ghatak, Arundhuti; Basu, Asish R.; Wakabayashi, John
of graywacke provenance has long been used to evaluate the record of tectonic process in orogenic belts. Our geochemical data from graywackes of the Franciscan subduction complex, California, show that the connection between sedimentary record and geologic processes may be more complex than previously believed. Trace elements and Nd-Sr-Pb isotopes of Franciscan graywackes indicate two sources types. One group lacking negative Eu anomaly (Eu/Eu* > 0.9), shows slightly concave-up heavy rare earth elements, arc-like trace element patterns, and western Pacific island arc-like Pb isotopes, reflecting derivation from older accreted oceanic-arc terranes in the Sierra Nevada-Klamath Mountains. The other group displays small negative Eu anomalies, with trace element patterns resembling post-Archean Australian shale and Pb isotopes similar to Jurassic-Cretaceous Sierran batholith. There is no systematic separation of these two groups by depositional ages. Thus, geochemistry of the graywackes may partly reflect variation in location of sediment delivery systems, rather than solely reflecting evolution of the neighboring arc. Variation of Nd-Sr isotopes with stratigraphic-age for the graywackes mimics the trends of the coeval Great Valley Group clastic-rocks, suggesting that (1) they share the same sediment sources, (2) there are no "exotic" sediment sources that fed the Franciscan trench, and (3) burial-exposure cycles for Franciscan clastic rocks were comparatively brief. Comparison of Franciscan graywacke and metabasite geochemistry corroborates earlier conclusions that metabasites had little or no chemical exchange with fluids from cosubducted graywacke. Detrital zircon age populations, major element chemistry, and detrital framework modes, when compared to our data suggest that the former three parameters underrepresent the mafic component of clastic sediment provenance.
Sequential biventricular pacing improves regional contractility, longitudinal function and dyssynchrony in patients with heart failure and prolonged QRS
Aims Biventricular pacing (BiP) is an effective treatment in systolic heart failure (HF) patients with prolonged QRS. However, approximately 35% of the patients receiving BiP are classified as non-responders. The aim of this study is to evaluate the acute effects of VV-optimization on systolic heart function. Methods Twenty-one HF patients aged 72 (46-88) years, QRS 154 (120-190) ms, were studied with echocardiography, Tissue Doppler Imaging (TDI) and 3D-echo the first day after receiving a BiP device. TDI was performed; during simultaneous pacing (LV-lead pacing 4 ms before the RV-lead) and during sequential pacing (LV 20 and 40 ms before RV and RV 20 and 40 ms before LV-lead pacing). Systolic heart function was studied by tissue tracking (TT) for longitudinal function and systolic maximal velocity (SMV) for regional contractility and signs of dyssynchrony assessed by time-delays standard deviation of aortic valve opening to SMV, AVO-SMV/SD and tissue synchronization imaging (TSI). Results The TT mean value preoperatively was 4,2 ▒ 1,5 and increased at simultaneous pacing to 5,0 ▒ 1,2 mm (p < 0,05), and at best VV-interval to 5,4 ▒ 1,2 (p < 0,001). Simultaneous pacing achieved better TT distance compared with preoperative in 16 patients (76%). However, it was still higher after VV-optimization in 12 patients 57%. Corresponding figures for SMV were 3,0 ▒ 0,7, 3,5 ▒ 0,8 (p < 0,01), and 3,6 ▒ 0,8 (p < 0,001). Also dyssynchrony improved. Conclusions VV-optimization in the acute phase improves systolic heart function more than simultaneous BiP pacing. Long-term effects should be evaluated in prospective randomized trials. PMID:20384995
Post infarction risk stratification using the 3-D angle between QRS complex and T-wave vectors
Marek Malik; Katerina Hnatkova; Velislav N. Batchvarov
Present experience with prospective identification of patients who might benefit from prophylactic antiarrhythmic intervention is restricted to risk stratification using left ventricular ejection fraction (LVEF). The precision of LVEF-based identification of high risk patients is neither highly sensitive nor highly specific. This study investigated risk stratification of 466 survivors of acute myocardial infarction (86 women, mean age 57.5 years) for
Searcy, James Kincheon
The flow-duration curve is a cumulative frequency curve that shows the percent of time specified discharges were equaled or exceeded during a given period. It combines in one curve the flow characteristics of a stream throughout the range of discharge, without regard to the sequence of occurrence. If the period upon which the curve is based represents the long-term flow of a stream, the curve may be used to predict the distribution of future flows for water- power, water-supply, and pollution studies. This report shows that differences in geology affect the low-flow ends of flow-duration curves of streams in adjacent basins. Thus, duration curves are useful in appraising the geologic characteristics of drainage basins. A method for adjusting flow-duration curves of short periods to represent long-term conditions is presented. The adjustment is made by correlating the records of a short-term station with those of a long-term station.
Is subjective duration a signature of coding efficiency?
Eagleman, David M.; Pariyadath, Vani
Perceived duration is conventionally assumed to correspond with objective duration, but a growing literature suggests a more complex picture. For example, repeated stimuli appear briefer in duration than a novel stimulus of equal physical duration. We suggest that such duration illusions appear to parallel the neural phenomenon of repetition suppression, and we marshal evidence for a new hypothesis: the experience of duration is a signature of the amount of energy expended in representing a stimulus, i.e. the coding efficiency. This novel hypothesis offers a unified explanation for almost a dozen illusions in the literature in which subjective duration is modulated by properties of the stimulus such as size, brightness, motion and rate of flicker. PMID:19487187
Transesophageal electrocardiography and adenosine in the diagnosis of wide complex tachycardia.
Lopez, J A; Lufschanowski, R; Massumi, A
The diagnosis of wide complex tachycardia based on surface electrocardiography can be difficult. Misdiagnosis occurs frequently and is commonly associated with increased morbidity and mortality. We describe a case of wide QRS complex tachycardia in which transesophageal electrocardiography and intravenous adenosine were used to obtain a reliable diagnosis. These are safe and readily available tools for elucidating the mechanism of wide complex tachyarrhythmias in hemodynamically stable patients. PMID:8061537
Long duration flights management
NASA Astrophysics Data System (ADS)
Sosa-Sesma, Sergio; Letrenne, Gķrard; Spel, Martin; Charbonnier, Jean-Marc
Long duration flights (LDF) require a special management to take the best decisions in terms of ballast consumption and instant of separation. As a contrast to short duration flights, where meteorological conditions are relatively well known, for LDF we need to include the meteorological model accuracy in trajectory simulations. Dispersions on the fields of model (wind, temperature and IR fluxes) could make the mission incompatible with safety rules, authorized zones and others flight requirements. Last CNES developments for LDF act on three main axes: 1. Although ECMWF-NCEP forecast allows generating simulations from a 4D point (altitude, latitude, longitude and UT time), result is not statistical, it is determinist. To take into account model dispersion a meteorological NCEP data base was analyzed. A comparison between Analysis (AN) and Forecast (FC) for the same time frame had been done. Result obtained from this work allows implementing wind and temperature dispersions on balloon flight simulator. 2. For IR fluxes, NCEP does not provide ascending IR fluxes in AN mode but only in FC mode. To obtain the IR fluxes for each time frame, satellite images are used. A comparison between FC and satellites measurements had been done. Results obtained from this work allow implementing flux dispersions on balloon flight simulator. 3. An improved cartography containing a vast data base had been included in balloon flight simulator. Mixing these three points with balloon flight dynamics we have obtained two new tools for observing balloon evolution and risk, one of them is called ASTERISK (Statistic Tool for Evaluation of Risk) for calculations and the other one is called OBERISK (Observing Balloon Evolution and Risk) for visualization. Depending on the balloon type (super pressure, zero pressure or MIR) relevant information for the flight manager is different. The goal is to take the best decision according to the global situation to obtain the largest flight duration with a minimum risk for population. Telemetry system is based on satellite communication technologies. Housekeeping data and GPS data are transferred to the Ground Station by IRIDIUM network. Gondola is interrogated automatically each hour and all data stocked onboard are downloaded to ground station. Communication takes a few minutes to transfer all data stocked from last request. Tools had been used in SCOUT-MIR campaign 2008 for the first time. The results obtained encourage CNES teams to improve ergonomics and functionalities of these prototype.
Time plane ECG feature extraction using Hilbert transform, variable threshold and slope reversal approach
S. K. Mukhopadhyay; M. Mitra; S. Mitra
The electrocardiogram (ECG) representing the electrical activity of the heart is the key bio-signal for aiding the clinical staff in disease diagnosis. Generally the various characteristic features of ECG are extracted and used for decision-making purposes. In the present paper, an accurate detection technique of various points of QRS complex, QRS duration, R peak height, T peak, T onset and
Hurley, J.P.; McCollor, D.P.; Selle, S.J.
A long duration ash probe includes a pressure shell connected to a port in a combustor with a sample coupon mounted on a retractable carriage so as to retract the sample coupon within the pressure shell during soot blowing operation of the combustor. A valve mounted at the forward end of the pressure shell is selectively closeable to seal the sample coupon within the shell, and a heating element in the shell is operable to maintain the desired temperature of the sample coupon while retracted within the shell. The carriage is operably mounted on a pair of rails within the shell for longitudinal movement within the shell. A hollow carrier tube connects the hollow cylindrical sample coupon to the carriage, and extends through the carriage and out the rearward end thereof. Air lines are connected to the rearward end of the carrier tube and are operable to permit coolant to pass through the air lines and thence through the carrier tube to the sample coupon so as to cool the sample coupon. 8 figs.
The time and duration of meiosis.
Bennett, M D
Ever since meiosis was recognized as a process there has been a continuing interest in its temporal aspects. Two main types of meiotic timing experiments have been conducted: first, experiments to estimate the duration of meiosis (and sometimes its stages); second, experiments to locate the sensitive stage(s) when exposure of meiocytes to various treatments can affect meiotic chromosome behaviour (e.g. pairing or recombination). Such experiments have played an important role in increasing our understanding of the meiotic process. The duration of meiosis has been estimated in about 70 organisms, including two prokaryotes (yeast and Chlamydomonas) and the following eukaryotes: 1 Basidiomycete (Coprinus lagopus), 2 Gymnosperms (Larix decidua and Thuja plicata gracilis). at least 39 angiosperms, and at least 26 animal species. The duration of female meiosis has been estimated in far fewer species than male meiosis. However, estimates of the duration of female meiosis are available for 6 angiosperms. Drosophila melanogaster, Xenopus laevis, and several mammals. Comparison of these data shows that the duration of meiosis is one of the most variable aspects of the meiotic process, ranging from less than 6 h in yeast to more than 40 years in the human female. Developmental holds at different stages of meiosis are common in plants and animals, and inevitably prolong the meiotic division. However, even among species without developmental holds, the duration of meiosis is very variable. For instance, in animals it ranges from about 1-2 days in male Drosophila melanogaster to more than 24 days in male Homo sapiens and several Orthopterans. Despite the large variation in the duration of meiosis three generalizations can be made: (i) first prophase is always very long compared with the remaining meiotic stages, (ii) the rate of meiotic development is very slow compared with the rate of development in dividing somatic meristem cells of the same organisms under the same conditions, (iii) the duration of meiosis is characteristic of the genotype and species. Four main factors have been recognized which effect or determine the duration of meiosis, namely (1) environmental factors (e.g. temperature); (2) nuclear DNA content; (3) ploidy level of the organism; and, (4) the genotype. Because nuclear DNA content plays a major role in determining the duration of meiosis, it has been suggested that DNA influences the rate of meiotic development in two ways: first through its informational content (the genotype), and second indirectly by the physical and mechanical effects of its mass independently of its informational content (i.e. the nucleotype). Thus, the observed duration of meiosis is the result of a complex genotype-nucleotype-environment interaction. With the obvious exception of variation caused by developmental holds, changes in the duration of meiosis usually involve proportional changes in the durations of all its stages... PMID:16285
Distortion of the Terminal Portion of the QRS on the Admission Electrocardiogram in Acute Myocardial Infarction and Correlation With Infarct Size and Long-Term Prognosis (Thrombolysis In Myocardial Infarction 4 Trial) * * This study was supported in part by a grant from SmithKline Beecham, Philadelphia, Pennsylvania
Yochai Birnbaum; Robert A. Kloner; Samuel Sclarovsky; Christopher P. Cannon; Carolyn H. McCabe; Vicki G. Davis; Barry L. Zaret; Frans J. Th. Wackers; Eugene Braunwald
Previous studies have shown an association between distortion of the terminal portion of the QRS (QRS[+] pattern: emergence of the J point ?50% of the R wave in leads with qR configuration, or disappearance of the S wave in leads with an Rs configuration) on admission and in-hospital mortality in acute myocardial infarction (AMI). However, the mechanism for this association
Estimating the duration of speciation from phylogenies.
Etienne, Rampal S; Morlon, HķlĶne; Lambert, Amaury
Speciation is not instantaneous but takes time. The protracted birth-death diversification model incorporates this fact and predicts the often observed slowdown of lineage accumulation toward the present. The mathematical complexity of the protracted speciation model has barred estimation of its parameters until recently a method to compute the likelihood of phylogenetic branching times under this model was outlined (Lambert et al. ). Here, we implement this method and study using simulated phylogenies of extant species how well we can estimate the model parameters (rate of initiation of speciation, rate of extinction of incipient and good species, and rate of completion of speciation) as well as the duration of speciation, which is a combination of the aforementioned parameters. We illustrate our approach by applying it to a primate phylogeny. The simulations show that phylogenies often do not contain enough information to provide unbiased estimates of the speciation-initiation rate and the extinction rate, but the duration of speciation can be estimated without much bias. The estimate of the duration of speciation for the primate clade is consistent with literature estimates. We conclude that phylogenies combined with the protracted speciation model provide a promising way to estimate the duration of speciation. PMID:24758256
Kana Ram Jat; Rakesh Lodha; Sushil K. Kabra
Arrhythmias in children can be classified according to their effect on central pulse: Fast pulse rate ¢ tachyarrhythmia; Slow\\u000a pulse rate ¢ bradyarrhythmia; and Absent pulse is pulseless arrest (cardiac arrest). Tachyarrythmia may be narrow complex\\u000a tachycardia (QRS duration ?0.08Ās): sinus tachycardia (ST), supraventricular tachycardia (SVT), atrial flutter or Wide-complex\\u000a tachycardia (QRS duration >0.08Ās): ventricular tachycardia (VT), SVT with aberrant
[Diagnostic application of external electrical impulses in form of an overdrive for the influence of an implanted QRS inhibited demand pacemaker system (author's transl)].
Rost, P; Pippig, L
The possibility of influencing an implanted demand pacemaker system by means of an external electrical impulse has already been described by several authors. In this paper further clinical applications of this method are discussed in relationship to patients who have a pacemaker of the QRS inhibited type. Electrodes are applied externally over the regions of the pacemaker generator and the catheter tip. Electrical impulses are then given at a higher frequency than those of the implanted pacemaker, thus enabling the impulses of the internal pacemaker to be inhibited, and consequently the spontaneous action of the heart to be observed. Further possible clinical applications with the aid of examples are discussed: the identification of persistent arrhythmias, digitalis intoxication, fresh cardiac ischaemias, as well as evidence of the need for temporary stimulation during generator change. PMID:1263990
JACEE long duration balloon flights
NASA Technical Reports Server (NTRS)
Burnett, T.; Dake, S.; Derrickson, J.; Fountain, W.; Fuki, M.; Gregory, J.; Hayashi, T.; Holynski, R.; Iwai, J.; Jones, W. V.
JACEE balloon-borne emulsion chamber detectors are used to observe the spectra and interactions of cosmic ray protons and nuclei in the energy range 1 to 100A TeV. Experience with long duration mid-latitude balloon flights and characteristics of the detector system that make it ideal for planned Antarctic balloon flights are discussed.
JACEE long duration balloon flights
Burnett, T.; Iwai, J.; Lord, J.J.; Strausz, S.; Wilkes, R.J. (Washington Univ., Seattle, WA (USA)); Dake, S.; Oda, H. (Kobe Univ. (Japan)); Miyamura, O. (Osaka Univ. (Japan)); Fuki, M. (Matsusho Gakuen Junior Coll., Matsumoto (Japan)); Jones, W.V. (National Aeronautics and Space Administration, Washington, DC (USA)); Gregory, J.; Hayashi, T.; Takahashi, U. (Alabama Univ., Huntsville, AL (USA)); Tominaga,
JACEE balloon-borne emulsion chamber detectors are used to observe the spectra and interactions of cosmic ray protons and nuclei in the energy range 1-100A TeV. Experience with long duration mid-latitude balloon flights and characteristics of the detector system that make it ideal for planned Antarctic balloon flights are discussed. 5 refs., 2 figs.
Extended Duration Orbiter Medical Project
NASA Technical Reports Server (NTRS)
Leach, C. S.; Pool, S. L.; Sawin, C. F.; Nicogossian, A. E.
The Extended Duration Orbiter (EDO) program addresses a need for more time to perform experiments and other tasks during Space Shuttle missions. As a part of this program, the Extended Duration Orbiter Medical Project (EDOMP) has been instituted to obtain information about physiologic effects of extending mission duration and the effectiveness of countermeasures against factors that might compromise crew health, safety, or performance on extended-duration missions. Only those investigations that address and characterize operational problems, develop countermeasures, or evaluate the effectiveness of countermeasures will be pursued. The EDOMP investigations will include flight-associated Detailed Supplementary Objectives as well as ground-based studies simulating the influence of microgravity. Investigator teams have been formed in the following areas: biomedical physiology, cardiovascular and fluid/electrolyte physiology, environmental health, muscle and exercise physiology, and neurophysiology. Major operational questions must be answered in each of these areas, and investigations have been designed to answer them. The EDO program will proceed only after countermeasures have been shown to be effective in preventing or mitigating the adverse changes they have been designed to attenuate. The program is underway and will continue on each Shuttle flight as the manifest builds toward a 16-day orbital flight.
Curricular internship Timing and Duration
Krause, Rolf
1 Art.1 Curricular internship Art.2 Objectives Art.3 Timing and Duration Art.4 Choice of Employer Art.5 Pertinence of the internship Art.6 Internship Search GRADUATE INTERNSHIP GUIDELINES Faculties training or work experience, herein referred to as `internship', is one of the graduation requirements. 2
Bayesian learning of speech duration models
Jen-tzung Chien; Chih-hsien Huang
This paper presents the Bayesian speech duration modeling and learning for hidden Markov model (HMM) based speech recognition. We focus on the sequential learning of HMM state duration using quasi-Bayes (QB) estimate. The adapted duration models are robust to nonstationary speaking rates and noise conditions. In this study, the Gaussian, Poisson, and gamma distributions are investigated to characterize the duration
Prediction of cardiovascular death and myocardial infarction by the QRS-T angle and T vector loop morphology after angioplasty in stable angina pectoris: an 8-year follow-up
Aigars Rubulis; Lennart Bergfeldt; Lars Rydķn; Jens Jensen
Reliable cardiovascular (CV) risk assessment by a noninvasive tool would be of great value for CV event prevention.The present study consists of 187 coronary artery disease patients with 8 years of follow-up. Eight vectorcardiographic parameters characterizing different aspects of ventricular repolarization were analyzed at baseline: (1) the ST-segment (ST-VM), (2) the T vector angles (QRS-T angle, Televation, and Tazimuth), (3)
Effect of Study Design on the Reported Effect of Cardiac Resynchronization Therapy (CRT) on Quantitative Physiological Measures: Stratified Meta?Analysis in Narrow?QRS Heart Failure and Implications for Planning Future Studies
Jabbour, Richard J.; Shun?Shin, Matthew J.; Finegold, Judith A.; Afzal Sohaib, S. M.; Cook, Christopher; Nijjer, Sukhjinder S.; Whinnett, Zachary I.; Manisty, Charlotte H.; Brugada, Josep; Francis, Darrel P.
Background Biventricular pacing (CRT) shows clear benefits in heart failure with wide QRS, but results in narrow QRS have appeared conflicting. We tested the hypothesis that study design might have influenced findings. Method and Results We identified all reports of CRT?P/D therapy in subjects with narrow QRS reporting effects on continuous physiological variables. Twelve studies (2074 patients) met these criteria. Studies were stratified by presence of bias?resistance steps: the presence of a randomized control arm over a single arm, and blinded outcome measurement. Change in each endpoint was quantified using a standardized effect size (Cohen's d). We conducted separate meta?analyses for each variable in turn, stratified by trial quality. In non?randomized, non?blinded studies, the majority of variables (10 of 12, 83%) showed significant improvement, ranging from a standardized mean effect size of +1.57 (95%CI +0.43 to +2.7) for ejection fraction to +2.87 (+1.78 to +3.95) for NYHA class. In the randomized, non?blinded study, only 3 out of 6 variables (50%) showed improvement. For the randomized blinded studies, 0 out of 9 variables (0%) showed benefit, ranging from ?0.04 (?0.31 to +0.22) for ejection fraction to ?0.1 (?0.73 to +0.53) for 6?minute walk test. Conclusions Differences in degrees of resistance to bias, rather than choice of endpoint, explain the variation between studies of CRT in narrow?QRS heart failure addressing physiological variables. When bias?resistance features are implemented, it becomes clear that these patients do not improve in any tested physiological variable. Guidance from studies without careful planning to resist bias may be far less useful than commonly perceived. PMID:25564370
Duration matters: Dissociating neural correlates of detection and evaluation of social gaze
Bojana Kuzmanovic; Alexandra L. Georgescu; Simon B. Eickhoff; Nadim J. Shah; Gary Bente; Gereon R. Fink; Kai Vogeley
The interpretation of interpersonal gaze behavior requires the use of complex cognitive processes and guides social interactions. Among a variety of different gaze characteristics, gaze direction and gaze duration modulate crucially the meaning of the ōsocial gazeö. Nevertheless, prior neuroimaging studies disregarded the relevance of gaze duration by focusing on gaze direction only.The present functional magnetic resonance imaging (fMRI) study
Business Cycle Duration Dependence: A Parametric Approach
Daniel E Sichel
This paper reexamines duration dependence in U.S. business cycles using parametric hazard models. Positive duration dependence would indicate that expansions or contractions are more likely to end as they become \\
12 CFR 1252.2 - Effective duration.
Code of Federal Regulations, 2010 CFR
... Effective duration. 1252.2 Section 1252.2 Banks and Banking FEDERAL HOUSING FINANCE AGENCY ENTERPRISES PORTFOLIO HOLDINGS ¦ 1252.2 Effective duration. This part shall be in effect for each Enterprise so long asŚ (a)...
12 CFR 1252.2 - Effective duration.
Code of Federal Regulations, 2011 CFR
... Effective duration. 1252.2 Section 1252.2 Banks and Banking FEDERAL HOUSING FINANCE AGENCY ENTERPRISES PORTFOLIO HOLDINGS ¦ 1252.2 Effective duration. This part shall be in effect for each Enterprise so long asŚ (a)...
12 CFR 1252.2 - Effective duration.
Code of Federal Regulations, 2014 CFR
... Effective duration. 1252.2 Section 1252.2 Banks and Banking FEDERAL HOUSING FINANCE AGENCY ENTERPRISES PORTFOLIO HOLDINGS ¦ 1252.2 Effective duration. This part shall be in effect for each Enterprise so long asŚ (a)...
12 CFR 1252.2 - Effective duration.
Code of Federal Regulations, 2013 CFR
... Effective duration. 1252.2 Section 1252.2 Banks and Banking FEDERAL HOUSING FINANCE AGENCY ENTERPRISES PORTFOLIO HOLDINGS ¦ 1252.2 Effective duration. This part shall be in effect for each Enterprise so long asŚ (a)...
12 CFR 1252.2 - Effective duration.
Code of Federal Regulations, 2012 CFR
... Effective duration. 1252.2 Section 1252.2 Banks and Banking FEDERAL HOUSING FINANCE AGENCY ENTERPRISES PORTFOLIO HOLDINGS ¦ 1252.2 Effective duration. This part shall be in effect for each Enterprise so long asŚ (a)...
Tracking Long Duration Flows in Network Traffic
Aiyou Chen; Yu Jin; Jin Cao; L. E. Li
¾We propose the tracking of long duration o ws as a new network measurement primitive. Long-duration o ws are characterized by their long lived nature in time, and may not have high trafc volumes. We propose an efcient data streaming algorithm to effectively track long duration o ws. Our basic technique is to maintain only two Bloom lters at any
Paul Collier; Anke Hoeffler
We have modeled the duration of large-scale, violent civil conflicts, applying hazardfunctions to a comprehensive data set of such conflicts for the period 1960-99. We findthat the duration of conflicts is determined by a substantially different set of variablesfrom those which determine the initiation. The duration of conflict is substantiallyincreased if the society is composed of a few large ethnic
Duration Prediction in Mandarin TTS System
Qing GUO; Nobuyuki Katae
This paper reports the methodology and results of decision tree based duration prediction for a Mandarin text-to-speech system developed by the Fujitsu Laboratories. Syllable initials and finals are the basic units in this duration study. Factors influencing finals duration such as phrase boundary and phone context are discussed in detail. Experiments indicate that it is the most important determinant of
Should HRT be duration limited?
Pitkin, Joan
Hormone Replacement Therapy (HRT) has received consistently bad press, despite re-analysis of previous data new studies and supporting Consensus Statements from leading national and international societies. Many women have been convinced by women's journals and the media not to even consider HRT as an option and, General Practitioners, still limit duration to 5 years or, will, arbitrarily, discontinue prescriptions in the early 50s. This article seeks to make sense of our current position. Previous and new evidence on the safety of HRT is reviewed. New data on the long-term consequences of non-treatment of women with Premature Ovarian Insufficiency (POI) is presented and the dichotomy of the older female workforce is explored. From this, a logical plan of management emerges. PMID:24336246
Cohabitation Duration and Transient Domesticity
Research finds that many impoverished urban Black adults engage in a pattern of partnering and family formation involving a succession of short cohabitations yielding children, a paradigm referred to as transient domesticity. Researchers have identified socioeconomic status, cultural adaptations, and urbanicity as explanations for aspects of this pattern. We used longitudinal data from the 2001 Survey of Income and Program Participation to analyze variation in cohabitation and marriage duration by race/ethnicity, income, and urban residence. Proportional hazards regression indicated that separation risk is greater among couples that are cohabiting, below 200% of the federal poverty line, and Black but is not greater among urban dwellers. This provides empirical demographic evidence to support the emerging theory of transient domesticity and suggests that both socioeconomic status and race explain this pattern. We discuss the implications of these findings for understanding transient domesticity and make recommendations for using the Survey of Income and Program Participation to further study this family formation paradigm. PMID:24273358
Extended Duration Orbiter Medical Project
NASA Technical Reports Server (NTRS)
Sawin, Charles F. (Editor); Taylor, Gerald R. (Editor); Smith, Wanda L. (Editor); Brown, J. Travis (Technical Monitor)
Biomedical issues have presented a challenge to flight physicians, scientists, and engineers ever since the advent of high-speed, high-altitude airplane flight in the 1940s. In 1958, preparations began for the first manned space flights of Project Mercury. The medical data and flight experience gained through Mercury's six flights and the Gemini, Apollo, and Skylab projects, as well as subsequent space flights, comprised the knowledge base that was used to develop and implement the Extended Duration Orbiter Medical Project (EDOMP). The EDOMP yielded substantial amounts of data in six areas of space biomedical research. In addition, a significant amount of hardware was developed and tested under the EDOMP. This hardware was designed to improve data gathering capabilities and maintain crew physical fitness, while minimizing the overall impact to the microgravity environment. The biomedical findings as well as the hardware development results realized from the EDOMP have been important to the continuing success of extended Space Shuttle flights and have formed the basis for medical studies of crew members living for three to five months aboard the Russian space station, Mir. EDOMP data and hardware are also being used in preparation for the construction and habitation of International Space Station. All data sets were grouped to be non-attributable to individuals, and submitted to NASA s Life Sciences Data Archive.
Electrocardiographic criteria for diagnosis of irregular broad complex tachycardia with a high sensitivity for preexcited atrial fibrillation.
Lau, E W; Pathamanathan, R K; Ng, G A; Griffith, M J
AF may appear as an irregular broad complex tachycardia (BCT) if atrioventricular conduction occurs via an accessory pathway (preexcited AF) or if bundle branch block (BBB), preexistent or rate related, exists in the His-Purkinje system (BBB-AF). While BBB-AF is relatively benign, preexcited AF may herald sudden cardiac death. Hence it is important that the two conditions can be reliably distinguished. Yet, there is no preexistent algorithms for this purpose. Griffith et al. previously proposed a simple algorithm for a similar problem, that of distinguishing the two differential diagnoses for regular BCT: VT and SVT with BBB, on the basis that unless the QRS morphologies in V1 and V6 are absolutely typical of BBB, VT will be diagnosed. The authors propose an extrapolation of this principle to irregular BCT by stating that, unless the QRS morphologies in V1 and V6 are absolutely typical of BBB, preexcited AF will be diagnosed. Seventy-five ECGs showing irregular BCT (41 preexcited AF and 34 BBB-AF) were shown to two fellows in electrophysiology who were given no other information and were instructed to diagnose preexcited AF unless the QRS morphology pattern was typical of BBB. Observer 1 achieved a sensitivity of 100% (41/41) and a specificity of 79% (27/34), while observer 2 achieved a sensitivity of 100% and a specificity of 85% (29/34). By QRS morphology pattern, an average sensitivity of 100% and specificity of 82% were achieved for the diagnosis of irregular BCT. The algorithm is simple and easy to implement and recommended for clinical use. PMID:11202244
Training for long duration space missions
NASA Technical Reports Server (NTRS)
Goldberg, Joseph H.
The successful completion of an extended duration manned mission to Mars will require renewed research effort in the areas of crew training and skill retention techniques. The current estimate of inflight transit time is about nine months each way, with a six month surface visit, an order of magnitude beyond previous U.S. space missions. Concerns arise when considering the level of skill retention required for highly critical, one time operations such as an emergency procedure or a Mars orbit injection. The factors responsible for the level of complex skill retention are reviewed, optimal ways of refreshing degraded skills are suggested, and a conceptual crew training design for a Mars mission is outlined. Currently proposed crew activities during a Mars mission were reviewed to identify the spectrum of skills which must be retained over a long time period. Skill retention literature was reviewed to identify those factors which must be considered in deciding when and which tasks need retraining. Task, training, and retention interval factors were identified. These factors were then interpreted in light of the current state of spaceflight and adaptive training systems.
Repair of Electronics for Long Duration Spaceflight
NASA Technical Reports Server (NTRS)
Pettegrew, Richard D.; Easton, John; Struk, Peter
To reduce mission risk, long duration spaceflight and exploration activities will require greater degrees of self-sufficiency with regards to repair capability than have ever been employed before in space exploration. The current repair paradigm of replacing Orbital Replacement Units (ORUs) of malfunctioning avionics and electronic hardware will be impractical, since carrying all of the spares that could possibly be needed for a long duration mission would require upmass and volume at unprecedented and unacceptable levels. A strategy of component-level repair for electronics, however, could significantly reduce the mass and volume necessary for spares and enhance mission safety via a generic contingency capability. This approach is already used to varying degrees by the U.S. Navy, where vessels at sea experience some similar constraints such as the need for self sufficiency for moderately long time periods, and restrictions on volume of repair spares and infrastructure. The concept of conducting component-level repairs of electronics in spacecraft requires the development of design guidelines for future avionics (to enable repair), development of diagnostic techniques to allow an astronaut to pinpoint the faulty component aboard a vastly complex vehicle, and development of tools and methodologies for dealing with the physical processes of replacing the component. This physical process includes tasks such as conformal coating removal and replacement, component removal, replacement, and alignment--all in the difficulty of a reduced gravity environment. Further, the gravitational effects on the soldering process must be characterized and accounted for to ensure reliability of the newly repaired components. The Component-Level Electronics-Assembly Repair (CLEAR) project under the NASA Supportability program was established to develop and demonstrate the practicality of this repair approach. CLEAR involves collaborative efforts between NASA s Glenn Research Center, Langley Research Center, Johnson Space Center, the National Center for Space Exploration Research, and the U.S. Navy. The project goals are 1) develop and demonstrate a manually-operated electronics repair capability to be conducted in a spacecraft environment; and 2) develop guidelines for designs of electronics that facilitates component-level repair for future space exploration efforts. This multi-faceted program utilizes a cross-disciplinary approach to examine pre- and post-repair diagnostics, conformal coating removal and replacement, component soldering, and electronics design for supportability. These areas are investigated by a combination of trade studies, ground based testing, reduced gravity aircraft testing, and actual spaceflight testing on the International Space Station (ISS) in multiple experiments. This paper details the efforts of this program, with emphasis on early trade study results, ground-based efforts, and two upcoming ISS experiments.
Stimulus Intensity and the Perception of Duration
ERIC Educational Resources Information Center
Matthews, William J.; Stewart, Neil; Wearden, John H.
This article explores the widely reported finding that the subjective duration of a stimulus is positively related to its magnitude. In Experiments 1 and 2 we show that, for both auditory and visual stimuli, the effect of stimulus magnitude on the perception of duration depends upon the background: Against a high intensity background, weak stimuliģ
Testing for duration dependence in economic cycles
Jonathan Ohn; Larry W. Taylor; Adrian Pagan
Summary In this paper, we discuss discrete-time tests for duration dependence. Two of our test statistics are new to the econometrics literature, and we make an important distinction between the discrete and continuous time frameworks. We then test for duration dependence in business and stock market cycles, and compare our results for business cycles with those of Diebold and Rudebusch
Retinotopic adaptation-based visual duration compression
Johnston, Alan
Retinotopic adaptation-based visual duration compression Cognitive, Perceptual and Brain Sciences of whether adaptation-based duration compression (A. Johnston, D. H. Arnold, & S. Nishida, 2006) takes place temporal frequency. However, using an adaptation schedule that minimizes any effect of adaptation
Duration Sensitivity Depends on Stimulus Familiarity
ERIC Educational Resources Information Center
Morewedge, Carey K.; Kassam, Karim S.; Hsee, Christopher K.; Caruso, Eugene M.
When people are asked to assess or compare the value of experienced or hypothetical events, one of the most intriguing observations is their apparent insensitivity to event duration. The authors propose that duration insensitivity occurs when stimuli are evaluated in isolation because they typically lack comparison information. People should beģ
Mortality Associated With Sleep Duration and Insomnia
Daniel F. Kripke; Lawrence Garfinkel; Deborah L. Wingard; Melville R. Klauber; Matthew R. Marler
Background: Patients often complain about insuffi- cient sleep or chronic insomnia in the belief that they need 8 hours of sleep. Treatment strategies may be guided by what sleep durations predict optimal survival and whether insomnia might signal mortality risks. Methods: In 1982, the Cancer Prevention Study II of the American Cancer Society asked participants about their sleep duration and
Adjustment of fixation duration in visual search
Ignace Th. C. Hooge; Casper J. Erkelens
To investigate whether fixation durations are adjusted to the duration of a foveal analysis task, we designed a search task in which each stimulus element yielded information about the position of the target. We asked subjects to look for the target by making eye movements in the direction indicated by each stimulus element. We explicitly asked the subjects to make
Decision tree based duration prediction in Mandarin
Qing Quo; N. Katae
This paper reports the methodology and results of decision tree based duration prediction for Mandarin text-to-speech system developed by the FUJITSU Laboratories. Syllable initials and finals are the basic units in our duration study. In this paper, the factors that influence the finals such as phrase boundary and phone context are discussed in detail. Experiments show that the prosodic factor
Repetition enhancement and memory effects for duration.
Wiener, Martin; Thompson, James C
A remarkable aspect of conscious perception is that moments carryover from one to the next, also known as temporal continuity. This ability is thus crucial for detecting regularities, such as in speech and music, and may rely on an accurate perception of time. Investigations of human time perception have detailed two electroencephalographic (EEG) components associated with timing, the contingent negative variation (CNV) and late positive component of timing (LPCt); however, the precise roles of these components in timing remain elusive. Recently, we demonstrated that the perception of duration is influenced by durations presented on prior trials, which we explained by the creation of an implicit memory standard that adapts to local changes in sequence presentation. Here, we turn to the neural basis of this effect. Human participants performed a temporal bisection task in which they were required to classify the duration of auditory stimuli into short and long duration categories; crucially, the presentation order was first-order counterbalanced, allowing us to measure the effect of each presented duration on the next. EEG recordings revealed that the CNV and LPCt signals both covaried with the duration presented on the current trial, with CNV predicting reaction time and LPCt predicting choice. Additionally, both signals covaried with the duration presented in the prior trial but in different ways, with the CNV amplitude reflecting the change in the memory standard and the LPCt reflecting decision uncertainty. Furthermore, we observed a repetition enhancement effect of duration only for the CNV, suggesting that this signal additionally indexes the similarity of successive durations. These findings demonstrate dissociable roles for the CNV and LPCt, and demonstrate that both signals are continuously updated on a trial-by-trial basis that reflects shifts in temporal decisions. PMID:25818689
Scaling of chew cycle duration in primates.
Ross, Callum F; Reed, David A; Washington, Rhyan L; Eckhardt, Alison; Anapol, Fred; Shahnoor, Nazima
The biomechanical determinants of the scaling of chew cycle duration are important components of models of primate feeding systems at all levels, from the neuromechanical to the ecological. Chew cycle durations were estimated in 35 species of primates and analyzed in conjunction with data on morphological variables of the feeding system estimating moment of inertia of the mandible and force production capacity of the chewing muscles. Data on scaling of primate chew cycle duration were compared with the predictions of simple pendulum and forced mass-spring system models of the feeding system. The gravity-driven pendulum model best predicts the observed cycle duration scaling but is rejected as biomechanically unrealistic. The forced mass-spring model predicts larger increases in chew cycle duration with size than observed, but provides reasonable predictions of cycle duration scaling. We hypothesize that intrinsic properties of the muscles predict spring-like behavior of the jaw elevator muscles during opening and fast close phases of the jaw cycle and that modulation of stiffness by the central nervous system leads to spring-like properties during the slow close/power stroke phase. Strepsirrhines show no predictable relationship between chew cycle duration and jaw length. Anthropoids have longer chew cycle durations than nonprimate mammals with similar mandible lengths, possibly due to their enlarged symphyses, which increase the moment of inertia of the mandible. Deviations from general scaling trends suggest that both scaling of the jaw muscles and the inertial properties of the mandible are important in determining the scaling of chew cycle duration in primates. PMID:18661474
Code of Federal Regulations, 2010 CFR
...OF AGRICULTURE GENERAL ADMINISTRATIVE POLICY FOR NON-ASSISTANCE COOPERATIVE AGREEMENTS General ¦ 550.6 Duration. REE may enter into non-assistance cooperative agreements for a period not to exceed five...
Code of Federal Regulations, 2014 CFR
...OF AGRICULTURE GENERAL ADMINISTRATIVE POLICY FOR NON-ASSISTANCE COOPERATIVE AGREEMENTS General ¦ 550.6 Duration. REE may enter into non-assistance cooperative agreements for a period not to exceed five...
Code of Federal Regulations, 2012 CFR
...OF AGRICULTURE GENERAL ADMINISTRATIVE POLICY FOR NON-ASSISTANCE COOPERATIVE AGREEMENTS General ¦ 550.6 Duration. REE may enter into non-assistance cooperative agreements for a period not to exceed five...
Code of Federal Regulations, 2011 CFR
...OF AGRICULTURE GENERAL ADMINISTRATIVE POLICY FOR NON-ASSISTANCE COOPERATIVE AGREEMENTS General ¦ 550.6 Duration. REE may enter into non-assistance cooperative agreements for a period not to exceed five...
Code of Federal Regulations, 2013 CFR
...OF AGRICULTURE GENERAL ADMINISTRATIVE POLICY FOR NON-ASSISTANCE COOPERATIVE AGREEMENTS General ¦ 550.6 Duration. REE may enter into non-assistance cooperative agreements for a period not to exceed five...
Code of Federal Regulations, 2011 CFR
...Station Authorization Procedures ¦ 21.443 Duration. (a) A DAS authorization is effective until it is surrendered or the Administrator suspends, revokes, or otherwise terminates it. (b) The DAS shall return the authorization certificate to the...
Code of Federal Regulations, 2010 CFR
...Station Authorization Procedures ¦ 21.443 Duration. (a) A DAS authorization is effective until it is surrendered or the Administrator suspends, revokes, or otherwise terminates it. (b) The DAS shall return the authorization certificate to the...
Ongoing behavior predicts perceptual report of interval duration
GouvĻa, Thiago S.; Monteiro, Tiago; Soares, Sofia; Atallah, Bassam V.; Paton, Joseph J.
The ability to estimate the passage of time is essential for adaptive behavior in complex environments. Yet, it is not known how the brain encodes time over the durations necessary to explain animal behavior. Under temporally structured reinforcement schedules, animals tend to develop temporally structured behavior, and interval timing has been suggested to be accomplished by learning sequences of behavioral states. If this is true, trial to trial fluctuations in behavioral sequences should be predictive of fluctuations in time estimation. We trained rodents in an duration categorization task while continuously monitoring their behavior with a high speed camera. Animals developed highly reproducible behavioral sequences during the interval being timed. Moreover, those sequences were often predictive of perceptual report from early in the trial, providing support to the idea that animals may use learned behavioral patterns to estimate the duration of time intervals. To better resolve the issue, we propose that continuous and simultaneous behavioral and neural monitoring will enable identification of neural activity related to time perception that is not explained by ongoing behavior. PMID:24672473
Chronotype and sleep duration: the influence of season of assessment.
Allebrandt, Karla V; Teder-Laving, Maris; Kantermann, Thomas; Peters, Annette; Campbell, Harry; Rudan, Igor; Wilson, James F; Metspalu, Andres; Roenneberg, Till
Little is known about human entrainment under natural conditions, partly due to the complexity of human behavior, torn between biological and social time and influenced by zeitgebers (light-dark cycles) that are progressively "polluted" (and thereby weakened) by artificial light. In addition, data about seasonal variations in sleep parameters are scarce. We, therefore, investigated seasonal variation in cross-sectional assessments of sleep/wake times of 9765 subjects from four European populations (EGCUT?=?Estonian Genome Centre, University of Tartu in Estonia; KORA?=?Cooperative Health Research in the Region of Augsburg in Germany; KORCULA?=?The Korcula study in Croatia; and ORCADES?=?The Orkney Complex Disease Study in Scotland). We identified time-of-year dependencies for the distribution of chronotype (phase of entrainment assessed as the mid-sleep time point on free days adjusted for sleep deficit of workdays) in cohorts from Estonia (EGCUT) and Germany (KORA). Our results indicate that season (defined as daylight saving time - DST and standard zonetime periods - SZT) specifications of photoperiod influence the distribution of chronotype (adjusted for age and sex). Second, in the largest investigated sample, from Estonia (EGCUT; N?=?5878), we could detect that seasonal variation in weekly average sleep duration was dependent on individual chronotype. Later chronotypes in this cohort showed significant variation in their average sleep duration across the year, especially during DST (1?h advance in social time from the end of March to end of October), while earlier chronotypes did not. Later chronotypes not only slept less during the DST period but the average chronotype of the population assessed during this period was earlier than during the SZT (local time for a respective time zone) period. More in detail, hierarchical multiple regression analyses showed that, beyond season of assessment (DST or SZT), social jetlag (SJl; the discrepancy between the mid sleep on free and work days - which varied with age and sex) contributed to a greater extent to the variation in sleep duration than chronotype (after taking into account factors that are known to influence sleep duration, i.e. age, sex and body mass index). Variation in chronotype was also dependent on age, sex, season of assessment and SJl (which is highly correlated with chronotype - SJl was larger among later chronotypes). In summary, subjective assessments of sleep/wake times are very reliable to assess internal time and sleep duration (e.g. reproducing sleep duration and timing tendencies related to age and sex across the investigated populations), but season of assessment should be regarded as a potential confounder. We identified in this study photoperiod (seasonal adaptation) and SJl as two main factors influencing seasonal variation in chronotype and sleep duration. In conclusion, season of assessment, sex and age have an effect on epidemiological variation in sleep duration, chronotype and SJl, and should be included in studies investigating associations between these phenotypes and health parameters, and on the development of optimal prevention strategies. PMID:24679223
Estimating magnitude and duration of incident delays
Garib, A. [Zagazig Univ. (Egypt). Construction Engineering Dept.; Radwan, A.E.; Al-Deek, H. [Univ. of Central Florida, Orlando, FL (United States). Dept. of Civil and Environmental Engineering
Traffic congestion is a major operational problem on urban freeways. In the case of recurring congestion, travelers can plan their trips according to the expected occurrence and severity of recurring congestion. However, nonrecurring congestion cannot be managed without real-time prediction. Evaluating the efficiency of intelligent transportation systems (ITS) technologies in reducing incident effects requires developing models that can accurately predict incident duration along with the magnitude of nonrecurring congestion. This paper provides two statistical models for estimating incident delay and a model for predicting incident duration. The incident delay models showed that up to 85% of variation in incident delay can be explained by incident duration, number of lanes affected, number of vehicles involved, and traffic demand before the incident. The incident duration prediction model showed that 81% of variation in incident duration can be predicted by number of lanes affected, number of vehicles involved, truck involvement, time of day, police response time, and weather condition. These findings have implications for on-line applications within the context of advanced traveler information systems (ATIS).
Thermoresponsive nanogels for prolonged duration local anesthesia
Hoare, Todd; Young, Stuart; Lawlor, Michael W.; Kohane, Daniel S.
Nanogels based on poly(N-isopropylacrylamide) are attractive vehicles for prolonged duration local anesthesia because of their tunable size, number of functional groups, thermoresponsiveness, and their anionic charge. Nerve block durations of up to nine hours were achieved using acrylic acid-loaded nanogels loaded with bupivacaine. Increasing the anionic charge density of the nanogels or (for more highly acid-functionalized nanogels) decreasing the nanogel size facilitated longer duration anesthetic release. Small (<300 nm diameter) nanogels formed dense aggregates upon injection in vivo and induced only mild inflammatory responses, while large (>500 nm diameter) nanogels typically remained as liquid-like residues in vivo and induced more severe inflammatory reactions. PMID:22732383
STS mission duration enhancement study: (orbiter habitability)
NASA Technical Reports Server (NTRS)
Carlson, A. D.
Habitability improvements for early flights that could be implemented with minimum impact were investigated. These included: (1) launching the water dispenser in the on-orbit position instead of in a locker; (2) the sleep pallet concept; and (3) suction cup foot restraints. Past studies that used volumetric terms and requirements for crew size versus mission duration were reviewed and common definitions of key habitability terms were established. An accurately dimensioned drawing of the orbiter mid-deck, locating all of the known major elements was developed. Finally, it was established that orbiter duration and crew size can be increased with minimum modification and impact to the crew module. Preliminary concepts of the aft med-deck, external versions of expanded tunnel adapters (ETA), and interior concepts of ETA-3 were developed and comparison charts showing the various factors of volume, weight, duration, size, impact to orbiter, and number of sleep stations were generated.
The Impact of the Potential Duration of Unemployment Benefits on the Duration of Unemployment
Lawrence F. Katz; Bruce D. Meyer
This paper uses two data sets to examine the impact of the potential duration of unemployment insurance (UI) benefits on the duration of unemployment and the time pattern of the escape rate from unemployment in the United States. The first part of the empirical work uses a large sample of household heads to examine differences in the unemployment spell distributions
[Optimal duration of anticoagulation of venous thromboembolism].
Savina, E Noel; Couturaud, F
The optimal duration of anticoagulation after venous thromboembolism (VTE) is determined according to the risk of recurrent VTE after stopping anticoagulant therapy and the risk of anticoagulant-related bleeding while on antivitamin K. Clinical risk factors appears to be determinant to predict the risk of recurrence whereas the influence of biochemical and morphological tests is uncertain. The risk of recurrent venous thromboembolism is low when the initial episode was provoked by a reversible major risk factor (surgery): 3 months of anticoagulation is optimal. Conversely, this risk is high when venous thromboembolism was unprovoked or associated with persistent risk factor (cancer): 6 months or more prolonged anticoagulation is warranted. After this first estimation, the duration of anticoagulation may be modulated according to the presence of additional minor risk factors (major thrombophilia, chronic pulmonary hypertension, massive pulmonary embolism): 6 months if VTE was provoked and 12 to 24 months if VTE was unprovoked. If the risk of anticoagulant related bleeding is high, the duration of anticoagulation should be shortened (3 months if VTE was provoked and 6 or 3 months if it was unprovoked). Lastly, if VTE occurred in the setting of a cancer, anticoagulation should be conducted for 6 months or more while cancer is active or on ongoing treatment. Despite an increasing knowledge of the risk factors of recurrent VTE, a number of issues remain unresolved; randomised trial comparing different duration of anticoagulation are needed. PMID:22177766
Duration, volume and volatility impact of trades
Simone Manganelli
This paper presents a framework to model duration, volume and returns simultaneously, obtaining an econometric reduced form that incorporates causal and feedback effects among these variables. The methodology is applied to two groups of stocks, classified according to trade intensity. We find that: (1) all stocks exhibit trading volume clustering (which is significantly higher for frequently traded stocks); (2) times
Short-Duration Simulations from Measurements.
Mitchell, Dean J.; Enghauser, Michael
A method is presented that ascribes proper statistical variability to simulations that are derived from longer-duration measurements. This method is applicable to simulations of either real-value or integer-value data. An example is presented that demonstrates the applicability of this technique to the synthesis of gamma-ray spectra.
Amodal completion as reflected by gaze durations
Gijs Plomp; Chie Nakatani; Valķrie Bonnardel
Abstract In two experiments amodal completion of partly occluded shapes was investigated by recording eye movements in a directed visual search task. Participantssearched arrays of shapes in a prescribed order for target figuresthat could partly beoccluded. Longer gaze durations were found on occlusion patterns thanon truncated control patterns for targets but not for non-targets. This effect of occlusion was restricted
Sleep Duration and Breast Cancer Phenotype
Khawaja, Ali; Rao, Santosh; Li, Li; Thompson, Cheryl L.
Emerging evidence suggests that short sleep is associated with an increased risk of cancer; however, little has been done to study the role of sleep on tumor characteristics. In this study, we evaluated the relationship between sleep duration and tumor phenotype in 972 breast cancer patients. Sleep duration was inversely associated with tumor grade (univariate P = 0.032), particularly in postmenopausal women (univariate P = 0.018). This association did not reach statistical significance after adjustments for age, race, body mass index, hormone replacement therapy use, alcohol consumption, smoking, and physical activity in the entire study sample (P = 0.052), but it remained statistically significant (P = 0.049) among post-menopausal patients. We did not observe a statistically significant association between sleep duration and stage at diagnosis, ER, or HER2 receptor status. These results present a modest association between short duration of sleep and higher grade breast cancer in post-menopausal women. Further work needs to be done to validate these findings. PMID:24319459
Calculating Stage Duration Statistics in Multistage Diseases
Komarova, Natalia L.; Thalhauser, Craig J.
Many human diseases are characterized by multiple stages of progression. While the typical sequence of disease progression can be identified, there may be large individual variations among patients. Identifying mean stage durations and their variations is critical for statistical hypothesis testing needed to determine if treatment is having a significant effect on the progression, or if a new therapy is showing a delay of progression through a multistage disease. In this paper we focus on two methods for extracting stage duration statistics from longitudinal datasets: an extension of the linear regression technique, and a counting algorithm. Both are non-iterative, non-parametric and computationally cheap methods, which makes them invaluable tools for studying the epidemiology of diseases, with a goal of identifying different patterns of progression by using bioinformatics methodologies. Here we show that the regression method performs well for calculating the mean stage durations under a wide variety of assumptions, however, its generalization to variance calculations fails under realistic assumptions about the data collection procedure. On the other hand, the counting method yields reliable estimations for both means and variances of stage durations. Applications to Alzheimer disease progression are discussed. PMID:22163291
Pitch and Duration Modification for Speech Watermarking
Sharma, Gaurav
Pitch and Duration Modification for Speech Watermarking Mehmet Celik, Gaurav Sharma and A. Murat of Engineering, Koc University, Istanbul, Turkey. Abstract-- We propose a speech watermarking algorithm based variability of these speech features allows watermarking modifications to be imperceptible to the human
Mapping Regional Precipitation Intensity Duration Frequency Estimates
David W. Watkins Jr.; Greg A. Link; Dennis Johnson
For regional precipitation frequency analyses, methods are needed to spatially interpolate or smooth point intensity duration frequency (IDF) estimates at gage sites for the purposes of visualization and estimation at ungaged sites. In this study to update IDF estimates for Michigan, the assumption is made that for practical purposes, the entire state may be treated as a homogeneous region in
Master of Biomolecular Science Duration: 2 years
Steels, Luc
FACULTy oF sCienCe WE Master of Biomolecular Science Duration: 2 years Start date: Last week and biotechnology. Indeed, our French fos- ter-university, the Universitķ Libre de Bruxelles, was internationally established its Institute of Molecular Biology (IMOL) from the start. Initially, our institute primarily
Duration of antiviral immunity after smallpox vaccination
Erika Hammarlund; Matthew W Lewis; Scott G Hansen; Lisa I Strelow; Jay A Nelson; Gary J Sexton; Jon M Hanifin; Mark K Slifka
Although naturally occurring smallpox was eliminated through the efforts of the World Health Organization Global Eradication Program, it remains possible that smallpox could be intentionally released. Here we examine the magnitude and duration of antiviral immunity induced by one or more smallpox vaccinations. We found that more than 90% of volunteers vaccinated 25¢75 years ago still maintain substantial humoral or
Electrocorticogram encoding of upper extremity movement duration.
Wang, Po T; King, Christine E; McCrimmon, Colin M; Shaw, Susan J; Millett, David E; Liu, Charles Y; Chui, Luis A; Nenadic, Zoran; Do, An H
Electrocorticogram (ECoG) is a promising long-term signal acquisition platform for brain-computer interface (BCI) systems such as upper extremity prostheses. Several studies have demonstrated decoding of arm and finger trajectories from ECoG high-gamma band (80-160 Hz) signals. In this study, we systematically vary the velocity of three elementary movement types (pincer grasp, elbow and shoulder flexion/extension) to test whether the high-gamma band encodes for the entirety of the movements, or merely the movement onset. To this end, linear regression models were created for the durations and amplitudes of high-gamma power bursts and velocity deflections. One subject with 8ū8 high-density ECoG grid (4 mm center-to-center electrode spacing) participated in the experiment. The results of the regression models indicated that the power burst durations varied directly with the movement durations (e.g. R(2)=0.71 and slope=1.0 s/s for elbow). The persistence of power bursts for the duration of the movement suggests that the primary motor cortex (M1) is likely active for the entire duration of a movement, instead of providing a marker for the movement onset. On the other hand, the amplitudes were less co-varied. Furthermore, the electrodes of maximum R(2) conformed to somatotopic arrangement of the brain. Also, electrodes responsible for flexion and extension movements could be resolved on the high-density grid. In summary, these findings suggest that M1 may be directly responsible for activating the individual muscle motor units, and future BCI may be able to utilize them for better control of prostheses. PMID:25570190
Suprasegmental Duration Modelling with Elastic Constraints in Automatic Speech RecognitionĀ
Molloy, Laurence; Isard, Stephen
-likelihood (provided by a set of tied-state triphone HMMs) and duration log-likelihood (provided by a set of durational models). The durational model used in the post-processing imposes syllable-level elastic constraints on the durational behaviour of speech segments...
Flow Duration at Selected Stream-Sites in Kentucky
Quinones, F.; Kiesler, J.; Macy, J.
Flow duration characteristics were determined for 195 streamflow stations in Kentucky. The data includes flow duration tables for the period of record of the stations based on mean daily discharges. Seasonal flow durations are also presented from monthly analysis of the data. At sites affected by regulation, tables are published showing both the before and after regulation flow duration data. (USGS)
The International Space Station as a Long-duration Space Exploration Test bed
Waliser, Duane E.
that utilizes existing flight hardware and ISS facilities in the areas of fluid physics, combustion scienceThe International Space Station as a Long-duration Space Exploration Test bed Benjamin J. Neumann and Technology Validation Test bed Ę ISS serves as a platform for complex Engineering Integration as well
VOGUE: A variable order hidden Markov model with duration based on frequent sequence mining
Mohammed J. Zaki; Christopher D. Carothers; Boleslaw K. Szymanski
We present VOGUE, a novel, variable order hidden Markov model with state durations, that combines two separate techniques for modeling complex patterns in sequential data: pattern mining and data modeling. VOGUE relies on a variable gap sequence mining method to extract frequent patterns with different lengths and gaps between elements. It then uses these mined sequences to build a variable
Mechanisms and functions for the duration of intercellular contacts made by lymphocytes
Daniel M. Davis
Communication across intercellular contacts is central to establishing appropriate innate and adaptive immune responses. Recent imaging of lymphocyte interactions suggests that a complex orchestration of cell¢cell contact times is a key correlate to establishing appropriate immune responses. Here I review the molecular and cellular processes that influence the duration of intercellular contacts, including integrin activation and dynamic changes in membrane
Performance Analysis of a Finite Duration Multichannel Delivery Method in IPTV
Weiqiang Sun; Kan Lin; Yang Guan
Reducing the channel change time is one of the major concerns of IPTV network deployment. This paper proposes multiple channels being delivered to household set top boxes, with a finite duration, to reduce channel change time. Unlike existing proprietary solutions that require additional equipment, or complex interactions between set top boxes and provisioning devices, the proposed method is easy to
Specifying and Deciding Quantified Discrete-time Duration Calculus Formulae using DCVALID
Paritosh K. Pandya
Quantified Discrete-time Duration Calculus (QDDC) is a logic for specifying properties of finite sequences of states. It provides novel interval based modalities to specify how a system evolves with time. In this note, we give the syntax and semantics of logic QDDC. We illustrate the ability of QDDC to model complex real-time requirements by an example of a mine pump.
The employment service and vacancy durations.
Behrenz, Lars
In the literature, there are few examples of studies analyzing the impact of labor market programs on vacancies. This article presents the results of a study of the impact of personnel increase at Swedish employment offices on vacancy durations. The evaluation method in the study is quasi-experimental. The main results of the study are as follows: (a) The increase of employment office staff members reduced their vacancy durations by approximately 2 days, and the probability that a vacancy is cancelled from the register is 1.17 times higher for the program offices; and (b) this effect is too small for the increase of staff members to represent a socially efficient use of resources and for a positive outcome in a public finance context. PMID:12465572
Fractals in trade duration: capturing long-range dependence and heavy tailedness in modeling trade duration
Wei Sun; Svetlozar Rachev; Frank J. Fabozzi; Petko S. Kalev
Several studies that have investigated a few stocks have found that the spacing between consecutive financial transactions\\u000a (referred to as trade duration) tend to exhibit long-range dependence, heavy tailedness, and clustering. In this study, we\\u000a empirically investigate whether a larger sample of stocks exhibit those characteristics. We do so by comparing goodness of\\u000a fit in modeling trade duration data for
Bounded Validity Checking of Interval Duration Logic
Babita Sharma; Supratik Chakraborty
A rich dense-time logic called Interval Duration Logic(IDL) is useful for specifying quantitative properties of timed systems. The logic is undecidable in general. However, several approaches can be used for checking validity (and model checking) of IDL formulae in practice. In this paper, we propose bounded validity checking of IDL formulae by polynomially reducing this to finding un-satisfying assignment of
The Duration of Civil War Peace Agreements
Karl Derouen; Jenna Lea; Peter Wallensteen
The focus of this article is civil war peace agreement duration from 1989 to 2005. Recent work by Hartzell and Hoddie (2003, 2007) has argued that power-sharing provisions have a cumulative impact. In other words, the more power-sharing provisions there are built into an agreement, the greater the prospects for peace. Our basic theoretical premise is that power-sharing provisions that
Evaluation of Long Duration Flight on Venus
NASA Technical Reports Server (NTRS)
Landis, Geoffrey A.; Colozza, Anthony J.
An analysis was performed to evaluate the potential of utilizing either an airship or aircraft as a flight platform for long duration flight within the atmosphere of Venus. In order to achieve long-duration flight, the power system for the vehicle had to be capable of operating for extended periods of time. To accomplish these, two types of power systems were considered, a solar energy-based power system utilizing a photovoltaic array as the main power source and a radioisotope heat source power system utilizing a Stirling engine as the heat conversion device. Both types of vehicles and power systems were analyzed to determine their flight altitude range. This analysis was performed for a station-keeping mission where the vehicle had to maintain a flight over a location on the ground. This requires the vehicle to be capable of flying faster than the wind speed at a particular altitude. An analysis was also performed to evaluate the altitude range and maximum duration for a vehicle that was not required to maintain station over a specified location. The results of the analysis show that each type of flight vehicle and power system was capable of flight within certain portions of Venus s atmosphere. The aircraft, both solar and radioisotope power proved to be the most versatile and provided the greatest range of coverage both for station-keeping and non-station-keeping missions.
Antenatal breastfeeding education for increasing breastfeeding duration
Lumbiganon, Pisake; Martis, Ruth; Laopaiboon, Malinee; Festin, Mario R; Ho, Jacqueline J; Hakimi, Mohammad
Background Breastfeeding (BF) is well recognised as the best food for infants. The impact of antenatal BF education on the duration of BF has not been evaluated. Objectives To evaluate the effectiveness of antenatal BF education for increasing BF initiation and duration. Search methods We searched the Cochrane Pregnancy and Childbirth GroupÆs Trials Register (21 April 2010), CENTRAL (The Cochrane Library 2010, Issue 2), MEDLINE (1966 to April 2010) and SCOPUS (January 1985 to April 2010). We contacted experts and searched reference lists of retrieved articles. We updated the search of the Pregnancy and Childbirth GroupÆs Trials Register on 28 September 2011 and added the results to the awaiting classification section of the review. Selection criteria All identified published, unpublished and ongoing randomised controlled trials (RCTs) assessing the effect of formal antenatal BF education or comparing two different methods of formal antenatal BF education, on duration of BF. We excluded RCTs that also included intrapartum or postpartum BF education. Data collection and analysis We assessed all potential studies identified as a result of the search strategy. Two review authors extracted data from each included study using the agreed form and assessed risk of bias. We resolved discrepancies through discussion. Main results We included 17 studies with 7131 women in the review and 14 studies involving 6932 women contributed data to the analyses. We did not do any meta-analysis because there was only one study for each comparison. Five studies compared a single method of BF education with routine care. Peer counselling significantly increased BF initiation. Three studies compared one form of BF education versus another. No intervention was significantly more effective than another intervention in increasing initiation or duration of BF. Seven studies compared multiple methods versus a single method of BF education. Combined BF educational interventions were not significantly better than a single intervention in initiating or increasing BF duration. However, in one trial a combined BF education significantly reduced nipple pain and trauma. One study compared different combinations of interventions. There was a marginally significant increase in exclusive BF at six months in women receiving a booklet plus video plus lactation consultation (LC) compared with the booklet plus video only. Two studies compared multiple methods of BF education versus routine care. The combination of BF booklet plus video plus LC was significantly better than routine care for exclusive BF at three months. AuthorsÆ conclusions Because there were significant methodological limitations and the observed effect sizes were small, it is not appropriate to recommend any antenatal BF education. There is an urgent need to conduct RCTs study with adequate power to evaluate the effectiveness of antenatal BF education. PMID:22071830
Maintenance Duration Estimate for a DEMO Fusion Power Plant, based on the EFDA WP12 pre-conceptual studies
Crofts, O
The erosion and high neutron flux in a fusion power plant results in the need for frequent remote replacement of the plasma facing components. This is a complex and time consuming remote handling operation and its duration directly affects the availability and therefore the commercial viability of the power plant. A tool is needed to allow the maintenance duration to be determined so that developments in component design can be assessed in terms of their effect on the maintenance duration. This allows the correct balance to be drawn between component cost and performance on the one hand and the remote handling cost and plant availability on the other.
Caffeine intake reduces sleep duration in adolescents.
Lodato, Francesca; Ara·jo, Joana; Barros, Henrique; Lopes, Carla; Agodi, Antonella; Barchitta, Martina; Ramos, Elisabete
In our study, we hypothesized that higher caffeine intake would be associated with lower sleep duration among 13-year-old adolescents. In addition, we aimed to identify food sources of caffeine intake in this sample. Eligible participants were adolescents who were born in 1990 and attended school in Porto, Portugal, in 2003/2004. Self-administered questionnaires were used, and diet was evaluated using a food frequency questionnaire. From the 2160 eligible participants, only 1522 with valid information regarding their diet were included in this study. In our sample, the median intake of caffeine was 23.1 mg/d, with soft drinks being the major source. Ice tea presented the highest median (25th-75th percentiles) contribution (33.1% [14.0-52.1]), followed by cola (21.1% [6.4-37.6]). Regarding cocoa products, chocolate bars presented a median contribution of 5.1% (1.0-14.0), and snacks containing chocolate had a contribution of 3.0% (0.5-7.2). Coffee and tea presented a negligible contribution. Adolescents who reported less sleep duration and those who spent more time watching TV during the weekend had a significantly higher caffeine intake. Overall, boys had higher intakes of caffeine from soft drinks, and private school attendees, those who had parents with more education, who reported less television viewing time and had lower body mass index presented higher intakes of caffeine from chocolate. Considering sleeping more than 9.5 hours as a reference class, for each increase of 10 mg/d in caffeine intake, we found that the odds ratio of sleeping 8.5 hours or less was 1.12 (95% confidence interval, 1.06-1.19). Our results support the hypothesis that caffeine intake was inversely associated with sleep duration in adolescents. PMID:24034572
The extended duration orbiter waste collection system
NASA Technical Reports Server (NTRS)
Brasseaux, Hubert J., Jr.; Winkler, H. E.; North, Jeffrey D.; Orlando, Samuel P.
A new waste collection system (WCS) is undergoing development for use in the extended duration orbiter (EDO). Requirements for missions up to 18 days and the capability for missions up to 30 days necessitate the development of a new WCS that will have the appropriate capacity. The new system incorporates design features from both Skylab and Space Shuttle Orbiter WCSs. The system for EDO utilizes redundant fans and urine separators. Plans call for the new WCS to be implemented for OV-105 (Endeavor) as well as for EDO. This paper describes the design and development status of the new WCS.
Long Duration Exposure Facility (LDEF) Archive System
NASA Technical Reports Server (NTRS)
Wilson, Brenda K.
The Long Duration Exposure Facility (LDEF) Archive System is designed to provide spacecraft designers and space environment researchers single point access to all available resources from LDEF. These include data, micrographs, photographs, technical reports, papers, hardware and test specimens, as well as technical expertise. Further, the LDEF Archive System is planned such that it could be the foundation for a NASA Space Environments and Effects (SEE) Archive System, with the addition of other spaceflight, laboratory and theoretical space environments and effects data and associated materials. This paper describes the current status and plans of the LDEF Archive System.
Long duration human exposure to microgravity
NASA Technical Reports Server (NTRS)
Huntoon, C. L.
Looking toward the era of long duration manned spaceflight, questions remain regarding human adaptation to the weightless environment. In particular, bone calcium loss, cardiovascular deconditioning, and effects of radiation require further study. NASA has undertaken a series of experiments to increase the knowledge base of human adaptation to spaceflight. To date, results in the area of cardiovascular deconditioning countermeasures are the furthest advanced. The results from the upcoming SLS-1 mission will enhance knowledge in all areas. With continued research, there is every confidence that astronauts will be able to be kept healthy for long periods of time.
10 CFR 451.6 - Duration of incentive payments.
Code of Federal Regulations, 2013 CFR
...false Duration of incentive payments. 451.6 Section 451.6 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION RENEWABLE ENERGY PRODUCTION INCENTIVES ¦ 451.6 Duration of incentive payments. Subject to the...
50 CFR 38.3 - Executive authority; duration.
Code of Federal Regulations, 2012 CFR
... 2012-10-01 false Executive authority; duration. 38...FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR (CONTINUED...NATIONAL WILDLIFE REFUGE Executive Authority; Authorized Powers...Emergency Authority ¦ 38.3 Executive authority; duration....
50 CFR 38.3 - Executive authority; duration.
Code of Federal Regulations, 2014 CFR
... 2014-10-01 false Executive authority; duration. 38...FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR (CONTINUED...NATIONAL WILDLIFE REFUGE Executive Authority; Authorized Powers...Emergency Authority ¦ 38.3 Executive authority; duration....
50 CFR 38.3 - Executive authority; duration.
Code of Federal Regulations, 2011 CFR
... 2011-10-01 false Executive authority; duration. 38...FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR (CONTINUED...NATIONAL WILDLIFE REFUGE Executive Authority; Authorized Powers...Emergency Authority ¦ 38.3 Executive authority; duration....
47 CFR 2.1509 - Environmental and duration tests.
Code of Federal Regulations, 2011 CFR
...2011-10-01 false Environmental and duration tests. 2.1509 Section 2.1509 Telecommunication...EPIRBs) Environmental and Operational Test Procedures ¦ 2.1509 Environmental and duration tests. The environmental and operational...
47 CFR 2.1509 - Environmental and duration tests.
Code of Federal Regulations, 2010 CFR
...2010-10-01 false Environmental and duration tests. 2.1509 Section 2.1509 Telecommunication...EPIRBs) Environmental and Operational Test Procedures ¦ 2.1509 Environmental and duration tests. The environmental and operational...
20 CFR 655.158 - Duration of positive recruitment.
Code of Federal Regulations, 2013 CFR
...2013-04-01 false Duration of positive recruitment. 655.158 Section 655.158 Employees' Benefits EMPLOYMENT AND TRAINING...H-2A Workers) Post-Acceptance Requirements ¦ 655.158 Duration of positive recruitment....
20 CFR 655.158 - Duration of positive recruitment.
Code of Federal Regulations, 2011 CFR
...2011-04-01 false Duration of positive recruitment. 655.158 Section 655.158 Employees' Benefits EMPLOYMENT AND TRAINING...H-2A Workers) Post-Acceptance Requirements ¦ 655.158 Duration of positive recruitment....
19 CFR 141.34 - Duration of power of attorney.
Code of Federal Regulations, 2012 CFR
...2012-04-01 2012-04-01 false Duration of power of attorney. 141.34 Section 141.34...TREASURY (CONTINUED) ENTRY OF MERCHANDISE Powers of Attorney ¦ 141.34 Duration of power of attorney. Powers of attorney...
19 CFR 141.34 - Duration of power of attorney.
Code of Federal Regulations, 2014 CFR
...2014-04-01 2014-04-01 false Duration of power of attorney. 141.34 Section 141.34...TREASURY (CONTINUED) ENTRY OF MERCHANDISE Powers of Attorney ¦ 141.34 Duration of power of attorney. Powers of attorney...
Time perception: paradigms, methods, target duration and individual differencesĀ
McFarlane, Henriett A
The present study assessed the role of the time judgement paradigms of prospective and retrospective durations, the length of durations and the effects of the states of mood and arousal in time perception. The role of ...
33 CFR 64.23 - Duration of marking on structures.
Code of Federal Regulations, 2011 CFR
...2011-07-01 false Duration of marking on structures. 64.23 Section 64.23 Navigation...SECURITY AIDS TO NAVIGATION MARKING OF STRUCTURES, SUNKEN VESSELS AND OTHER OBSTRUCTIONS Structures ¦ 64.23 Duration of marking on...
33 CFR 64.23 - Duration of marking on structures.
Code of Federal Regulations, 2010 CFR
...2010-07-01 false Duration of marking on structures. 64.23 Section 64.23 Navigation...SECURITY AIDS TO NAVIGATION MARKING OF STRUCTURES, SUNKEN VESSELS AND OTHER OBSTRUCTIONS Structures ¦ 64.23 Duration of marking on...
24 CFR 203.267 - Duration of periodic MIP.
Code of Federal Regulations, 2013 CFR
...2013-04-01 2013-04-01 false Duration of periodic MIP. 203.267 Section 203.267 ...Obligations Mortgage Insurance Premiums-Periodic Payment ¦ 203.267 Duration of periodic MIP. The mortgagee shall pay the...
24 CFR 203.267 - Duration of periodic MIP.
Code of Federal Regulations, 2014 CFR
...2014-04-01 2014-04-01 false Duration of periodic MIP. 203.267 Section 203.267 ...Obligations Mortgage Insurance Premiums-Periodic Payment ¦ 203.267 Duration of periodic MIP. The mortgagee shall pay the...
24 CFR 203.267 - Duration of periodic MIP.
Code of Federal Regulations, 2012 CFR
...2012-04-01 2012-04-01 false Duration of periodic MIP. 203.267 Section 203.267 ...Obligations Mortgage Insurance Premiums-Periodic Payment ¦ 203.267 Duration of periodic MIP. The mortgagee shall pay the...
24 CFR 203.267 - Duration of periodic MIP.
Code of Federal Regulations, 2011 CFR
...2011-04-01 2011-04-01 false Duration of periodic MIP. 203.267 Section 203.267 ...Obligations Mortgage Insurance Premiums-Periodic Payment ¦ 203.267 Duration of periodic MIP. The mortgagee shall pay the...
24 CFR 203.267 - Duration of periodic MIP.
Code of Federal Regulations, 2010 CFR
...2010-04-01 2010-04-01 false Duration of periodic MIP. 203.267 Section 203.267 ...Obligations Mortgage Insurance Premiums-Periodic Payment ¦ 203.267 Duration of periodic MIP. The mortgagee shall pay the...
46 CFR 189.60-40 - Duration of Convention certificates.
Code of Federal Regulations, 2011 CFR
...2011-10-01 false Duration of Convention certificates. 189.60-40 ...Certificates Under International Convention for Safety of Life at Sea, 1974 ¦ 189.60-40 Duration of Convention certificates. (a) The...
46 CFR 91.60-40 - Duration of Convention certificates.
Code of Federal Regulations, 2011 CFR
...2011-10-01 false Duration of Convention certificates. 91.60-40 ...Certificates Under International Convention for Safety of Life at Sea, 1974 ¦ 91.60-40 Duration of Convention certificates. (a) The...
46 CFR 91.60-40 - Duration of Convention certificates.
Code of Federal Regulations, 2010 CFR
...2010-10-01 false Duration of Convention certificates. 91.60-40 ...Certificates Under International Convention for Safety of Life at Sea, 1974 ¦ 91.60-40 Duration of Convention certificates. (a) The...
46 CFR 189.60-40 - Duration of Convention certificates.
Code of Federal Regulations, 2010 CFR
...2010-10-01 false Duration of Convention certificates. 189.60-40 ...Certificates Under International Convention for Safety of Life at Sea, 1974 ¦ 189.60-40 Duration of Convention certificates. (a) The...
29 CFR 1919.5 - Duration and renewal of accreditation.
Code of Federal Regulations, 2012 CFR
...2012-07-01 false Duration and renewal of accreditation. 1919.5 Section 1919.5 Labor...CERTIFICATION Procedure Governing Accreditation ¦ 1919.5 Duration and renewal of accreditation. The period of accreditation...
29 CFR 1919.5 - Duration and renewal of accreditation.
Code of Federal Regulations, 2014 CFR
...2014-07-01 false Duration and renewal of accreditation. 1919.5 Section 1919.5 Labor...CERTIFICATION Procedure Governing Accreditation ¦ 1919.5 Duration and renewal of accreditation. The period of accreditation...
29 CFR 1919.5 - Duration and renewal of accreditation.
Code of Federal Regulations, 2013 CFR
...2013-07-01 false Duration and renewal of accreditation. 1919.5 Section 1919.5 Labor...CERTIFICATION Procedure Governing Accreditation ¦ 1919.5 Duration and renewal of accreditation. The period of accreditation...
29 CFR 1919.5 - Duration and renewal of accreditation.
Code of Federal Regulations, 2010 CFR
...2010-07-01 false Duration and renewal of accreditation. 1919.5 Section 1919.5 Labor...CERTIFICATION Procedure Governing Accreditation ¦ 1919.5 Duration and renewal of accreditation. The period of accreditation...
19 CFR 141.34 - Duration of power of attorney.
Code of Federal Regulations, 2010 CFR
...2010-04-01 2010-04-01 false Duration of power of attorney. 141.34 Section 141.34...TREASURY (CONTINUED) ENTRY OF MERCHANDISE Powers of Attorney ¦ 141.34 Duration of power of attorney. Powers of attorney...
19 CFR 141.34 - Duration of power of attorney.
Code of Federal Regulations, 2011 CFR
...2011-04-01 2011-04-01 false Duration of power of attorney. 141.34 Section 141.34...TREASURY (CONTINUED) ENTRY OF MERCHANDISE Powers of Attorney ¦ 141.34 Duration of power of attorney. Powers of attorney...
CONCORDIASI, Long Duration Stratospheric Balloons over Antarctica
NASA Astrophysics Data System (ADS)
Cocquerez, Philippe
CNES, the French space agency, has been developing and operating stratospheric balloons for scientific purposes for many years. One particular type of balloon has been designed for ultra long duration flights in the lowermost stratosphere: the superpressure balloon. A constellation of typically 10 to 20 balloons, fitted with light payloads can be deployed, forming a regional airborne observatory. The first use of this kind of observation system has been for atmospheric sciences, each of the balloons carrying various sets of scientific instruments. Concordiasi is the latest program built on the use of this observation system in its most recent development stage. 19 balloons were released from McMurdo Station Antarctica over September to October 2010 in the Winter Polar Vortex. It carried a variety of instruments, for remote and in-situ measurement of the atmosphere. The average flight duration of the balloons was 69 days, cumulating to 1316 days over the whole balloon constellation. We will present briefly the scientific objectives of the project; describe the flight system and the flight campaign, including the launch phase and the long flight monitoring through the control centres. Flight results will be presented, with an overview of the scientific results, but focussing mainly on the technical achievements and on lessons that can be drawn from this project.
Star Clusters and the Duration of Starbursts
G. R. Meurer
The duration of starbursts is important for determining how they are regulated and the impact they have on their environment. Starbursts contain numerous prominent star clusters which typically comprise in total ~20% of the ultraviolet light, embedded in a diffuse glow of recently formed stars responsible for the dominant ~80%. Hubble Space Telescope images have been obtained for four starburst galaxies in order to determine their burst duration from the ages of their star clusters. Preliminary results for NGC3310 are reported here. The UBI colors of its clusters and diffuse light give consistent results. The clusters have a broad range of colors, consistent with a population of instantaneous bursts with ages ranging from 0 to a few 100 Myr. The diffuse light has a narrow range of color consistent with continuous star formation over timescales ranging from ~ 10 to 100 Myr. Hence NGC3310's starburst has lasted ~100 Myr, or about 10 times the crossing time. Other results noted in the literature also indicate bursts lasting several times longer than the crossing time. These results suggest that starbursts are not self-extinguishing flashes. Rather they are sustainable, perhaps self-regulated.
Decoding stimulus duration from neural responses in the auditory midbrain.
Aubie, Brandon; Sayegh, Riziq; Fremouw, Thane; Covey, Ellen; Faure, Paul A
Neurons with responses selective for the duration of an auditory stimulus are called duration-tuned neurons (DTNs). Temporal specificity in their spiking suggests that one function of DTNs is to encode stimulus duration; however, the efficacy of duration encoding by DTNs has yet to be investigated. Herein, we characterize the information content of individual cells and a population of DTNs from the mammalian inferior colliculus (IC) by measuring the stimulus-specific information (SSI) and estimated Fisher information (FI) of spike count responses. We found that SSI was typically greatest for those stimulus durations that evoked maximum spike counts, defined as best duration (BD) stimuli, and that FI was maximal for stimulus durations off BD where sensitivity to a change in duration was greatest. Using population data, we demonstrate that a maximum likelihood estimator (MLE) can accurately decode stimulus duration from evoked spike counts. We also simulated a two-alternative forced choice task by having MLE models decide whether two durations were the same or different. With this task we measured the just-noticeable difference threshold for stimulus duration and calculated the corresponding Weber fractions across the stimulus domain. Altogether, these results demonstrate that the spiking responses of DTNs from the mammalian IC contain sufficient information for the CNS to encode, decode, and discriminate behaviorally relevant auditory signal durations. PMID:25122706
Modeling syllable duration in Indian languages using neural networks
K. Sreenivasa Rao; B. Yegnanarayana
We propose a neural network model for predicting the syllable duration in Indian languages. A four layer feedforward neural network trained with a backpropagation algorithm is used for modeling the syllable duration. Analysis is performed on broadcast news data in Hindi, Telugu and Tamil in order to predict the duration of syllables in these languages using a neural network model.
Decision Tree based Duration Prediction in Mandarin TTS System
Qing Guo; Nobuyuki Katae; Hao Yu; Hitoshi Iwamida
This paper reports the methodology and results of decision tree based duration prediction for a Mandarin text-to-speech system developed by the Fujitsu Laboratories. Syllable initials and finals are the basic units in this duration study. Factors influencing finals duration such as phrase boundary and phone context are discussed in detail. Experiments indicate that it is the most important determinant of
Evaluating observational methods to quantify snow duration under diverse forest canopies
NASA Astrophysics Data System (ADS)
Dickerson-Lange, Susan E.; Lutz, James A.; Martin, Kael A.; Raleigh, Mark S.; Gersonde, Rolf; Lundquist, Jessica D.
Forests cover almost 40% of the seasonally snow-covered regions in North America. However, operational snow networks are located primarily in forest clearings, and optical remote sensing cannot see through tree canopies to detect forest snowpack. Due to the complex influence of the forest on snowpack duration, ground observations in forests are essential. We therefore consider the effectiveness of different strategies to observe snow-covered area under forests. At our study location in the Pacific Northwest, we simultaneously deployed fiber-optic cable, stand-alone ground temperature sensors, and time-lapse digital cameras in three diverse forest treatments: control second-growth forest, thinned forest, and forest gaps (one tree height in diameter). We derived fractional snow-covered area and snow duration metrics from the colocated instruments to assess optimal spatial resolution and sampling configuration, and snow duration differences between forest treatments. The fiber-optic cable and the cameras indicated that mean snow duration was 8 days longer in the gap plots than in the control plots (p < 0.001). We conducted Monte Carlo experiments for observing mean snow duration in a 40 m forest plot, and found the 95% confidence interval was ▒5 days for 10 m spacing between instruments and ▒3 days for 6 m spacing. We further tested the representativeness of sampling one plot per treatment group by observing snow duration across replicated forest plots at the same elevation, and at a set of forest plots 250 m higher. Relative relationships between snow duration in the forest treatments are consistent between replicated plots, elevation, and two winters of data.
HIAD at NFAC - Duration: 9 seconds.
Timelapse video of a six-meter (19.7 ft), inflatable Hypersonic Inflatable Aerodynamic Decelerator (HIAD) article being prepared for testing in the National Full-Scale Aerodynamic Complex at Moffet...
Why Are Teams Important? - Duration: 88 seconds.
Kelvin Kirby, deputy director for the Center for Radiation Engineering and Science for Space Exploration, or CRESSE, at Prairie View A&M University, explains how the complexity of space radiation m...
Prediction of Daily Flow Duration Curves and Streamflow for Ungauged Catchments Using Regional Flow Duration Curves
This study presents a method to predict flow duration curves (FDCs) and streamflow for ungauged catchments in the Mid-Atlantic Region, USA. We selected 29 catchments from the Appalachian Plateau, Ridge and Valley, and Piedmont physiographic provinces to develop and test the propo...
Long Duration Backlighter Experiments at Omega
Reighard, A; Glendinning, S; Young, P; Hsing, W; Foord, M; Schneider, M; Lu, K; Dittrich, T; Wallace, R; Sorce, C
We have successfully demonstrated a 7.5 ns-duration pinhole-apertured backlighter at the Omega laser facility. Pinhole-apertured point-projection backlighting for 8 ns will be useful for imaging evolving features in experiments at the National Ignition Facility. The backlighter consisted of a 20 {micro}m diameter pinhole in a 75 {micro}m thick Ta substrate separated from a Zn emitter (9 keV) by a 400 {micro}m thick high-density carbon piece. The carbon prevented the shock from the laser-driven surface from reaching the substrate before 8 ns and helped minimize x-ray ablation of the pinhole substrate. Grid wires in x-ray framing camera images of a gold grid have a source-limited resolution significantly smaller than the pinhole diameter due to the high aspect ratio of the pinhole, but do not become much smaller at late times.
Drug stability analyzer for long duration spaceflights
NASA Astrophysics Data System (ADS)
Shende, Chetan; Smith, Wayne; Brouillette, Carl; Farquharson, Stuart
Crewmembers of current and future long duration spaceflights require drugs to overcome the deleterious effects of weightlessness, sickness and injuries. Unfortunately, recent studies have shown that some of the drugs currently used may degrade more rapidly in space, losing their potency well before their expiration dates. To complicate matters, the degradation products of some drugs can be toxic. Consequently there is a need for an analyzer that can determine if a drug is safe at the time of use, as well as to monitor and understand space-induced degradation, so that drug types, formulations, and packaging can be improved. Towards this goal we have been investigating the ability of Raman spectroscopy to monitor and quantify drug degradation. Here we present preliminary data by measuring acetaminophen, and its degradation product, p-aminophenol, as pure samples, and during forced degradation reactions.
Short Duration Base Heating Test Improvements
NASA Technical Reports Server (NTRS)
Bender, Robert L.; Dagostino, Mark G.; Engel, Bradley A.; Engel, Carl D.
Significant improvements have been made to a short duration space launch vehicle base heating test technique. This technique was first developed during the 1960's to investigate launch vehicle plume induced convective environments. Recent improvements include the use of coiled nitrogen buffer gas lines upstream of the hydrogen / oxygen propellant charge tubes, fast acting solenoid valves, stand alone gas delivery and data acquisition systems, and an integrated model design code. Technique improvements were successfully demonstrated during a 2.25% scale X-33 base heating test conducted in the NASA/MSFC Nozzle Test Facility in early 1999. Cost savings of approximately an order of magnitude over previous tests were realized due in large part to these improvements.
Amodal completion as reflected by gaze durations.
Plomp, Gijs; Nakatani, Chie; Bonnardel, Valķrie; van Leeuwen, Cees
In two experiments amodal completion of partly occluded shapes was investigated by recording eye movements in a directed visual-search task. Participants searched arrays of shapes in a prescribed order for target figures that could partly be occluded. Longer gaze durations were found on occlusion patterns than on truncated control patterns for targets but not for non-targets. This effect of occlusion was restricted to a subset of the stimuli. A second experiment was carried out to establish whether this restriction resulted from structural properties of the stimuli or their familiarity. Occlusion patterns in this experiment were ambiguous with respect to structure, allowing both local and global completions. One of the completions was always less familiar than the other. The results showed longer gazes only for the less familiar completions, irrespective of whether they were local or global. PMID:15693664
The duration of Plasmodium falciparum infections.
Ashley, Elizabeth A; White, Nicholas J
Plasmodium vivax and Plasmodium ovale are often considered the malaria parasites best adapted to long-term survival in the human host because of their latent exo-erythrocytic forms. The prevailing opinion until the middle of the last century was that the maximum duration of Plasmodium falciparum infections was less than two years. Case reports and series investigating blood donors following accidental malaria infection of blood transfusion recipients and other sporadic malaria cases in non-endemic countries have shown clearly that asymptomatic P. falciparum infections may persist for up to a decade or longer (maximum confirmed 13 years). Current policies in malaria-free countries of excluding blood donors who have lived in malarious areas are justified. Vigilance for longer than three years after declaring elimination in an area may be needed. PMID:25515943
Long Duration Exposure Facility: A general overview
NASA Technical Reports Server (NTRS)
Oneal, Robert L.; Lightner, E. Burton
The Long Duration Exposure Facility (LDEF) is a large, low-cost, reusable, unmanned, free-flying spacecraft which accommodates technology, science, and applications experiments for long-term exposure to the space environment. The LDEF was designed and built by the NASA Langley Research Center (LaRC) for NASA's Office of Aeronautics and Space Technology. Specifically, the LDEF was designed to transport experiments into space via the Space Shuttle, to free fly in Earth orbit for an extended period, and be retrieved on a later Space Shuttle flight allowing experiments to be returned to Earth for postflight analysis in the laboratory. The LDEF with a full complement of experiments was placed in Earth orbit in April 1984 by Challenger and retrieved from orbit in January 1990 by Columbia. A general overview of the LDEF, its mission, systems, experiments, and operations is presented. Excerpts from various NASA documents are extensively used.
Evaluating Observational Methods to Quantify Snow Duration under Diverse Forest Canopies
NASA Astrophysics Data System (ADS)
Dickerson-Lange, S. E.; Lutz, J. A.; Martin, K.; Raleigh, M. S.; Gersonde, R.; Lundquist, J. D.
Forests cover over 40% of the seasonally snow-covered regions in North America. However, operational snow networks are located primarily in forest clearings, and optical remote sensing cannot see through tree canopies to detect forest snowpack. Due to the complex influence of the forest on snowpack duration, ground observations in forests are essential. We therefore consider the effectiveness of different strategies to observe snow covered area under forests. At our study location in the Pacific Northwest, we simultaneously deployed fiber-optic cable, stand-alone ground temperature sensors, and time-lapse digital cameras in three different forest treatments: control second-growth forest, thinned forest, and forest gaps (one tree height in diameter). We derived fractional snow covered area and snow duration metrics from the co-located instruments to assess optimal spatial resolution and sampling configuration. The fiber-optic cable and the camera detected a significant difference of 8 days in mean snow duration between the gap and control plots. Monte Carlo experiments based on our results suggest that 10 m spacing of self-recording ground temperature sensors across a 40 m forest plot will capture mean snow duration to ▒ 5 days whereas 6 m spacing reduces the 95% confidence interval to ▒ 3 days. We further tested the representativeness of sampling one plot per treatment group by observing snow duration across replicated forest plots at the same elevation, and at a set of forest plots 250 m higher. Relative relationships between snow duration in the forest treatments are consistent between replicated plots, elevation, and two winters of data.
Long Duration Space Materials Exposure (LDSE)
NASA Technical Reports Server (NTRS)
Allen, David; Schmidt, Robert
The Center on Materials for Space Structures (CMSS) at Case Western Reserve University is one of seventeen Commercial Centers for the Development of Space. It was founded to: (1) produce and evaluate materials for space structures; (2) develop passive and active facilities for materials exposure and analysis in space; and (3) develop improved material systems for space structures. A major active facility for materials exposure is proposed to be mounted on the exterior truss of the Space Station Freedom (SSF). This Long Duration Space Materials Exposure (LDSE) experiment will be an approximately 6 1/2 ft. x 4 ft. panel facing into the velocity vector (RAM) to provide long term exposure (up to 30 years) to atomic oxygen, UV, micro meteorites, and other low earth orbit effects. It can expose large or small active (instrumented) or passive samples. These samples may be mounted in a removable Materials Flight Experiment (MFLEX) carrier which may be periodically brought into the SSF for examination by CMSS's other SSF facility, the Space Materials Evaluation Facility (SMEF), which will contain a Scanning Electron Microscope, a Variable Angle & Scanning Ellipsometer, a Fourier Transform Infrared Spectrometer, and other analysis equipment. These facilities will allow commercial firms to test their materials in space and promptly obtain information on their materials survivability in the LEO environment.
Sharma; Gyaneshwar; Joshi, D.; Aryya, N. C.; Pandey, V. B.
Swarna ¢ Vanga, an Ayurvedic preparation, is used in the treatment mainly of Pramehas (genitor urinary and metabolic disorders), Sveta Pradara (Leucorrhoea), Kasa ¢ Swasa (Respiratory disorders), etc. The drug contains tin and sulphur as major components along with traces of mercury, iron and aluminum. According to modern point of view certain metals have been claimed toxic to both human and animal. Since Svarna ¢ Vanga contains these metals, it is essential to screen out its toxic effect, if any, although it is claimed in Ayurveda that when a metal is processed as prescribed, it become non ¢ toxic or the least toxic. Considering the above facts, an animal experiment was carried out for short duration (14 days) to screen the toxic effects of Svarna ¢ Vanga (SV) in increasing doses of the drug starting from the maximum therapeutic dose (12.5 mg / 100 gm b.wt / day). The drug was found to have no toxic effects in tissues of the animal at doses of 12.5 mg and 25 mg / 100 gm b.wt. / day. Fine fatty vacuolization in liver and focal superficial mucosal degeneration and necrosis of small intestine confined to one animal each at dose of 50 mg / 100gm b.wt. and 100 mg/ 100 gm. b.wt. / day were observed. Our study indicates that the drug has no toxic effect on tissues at therapeutic dose. PMID:22557505
Immune changes during short-duration missions
NASA Technical Reports Server (NTRS)
Taylor, G. R.
Spaceflight materially influences the immune mechanism of humans and animals. Effects resulting from missions of less than 1 month are examined. Effects from longer missions are discussed in the companion paper by Konstantinova et al. Most immunology studies have involved analyses of subjects and samples from subjects obtained after flight, with the data being compared with similar data obtained before flight. These studies have demonstrated that short-duration missions can result in a postflight depression in blast cell transformation, major changes in cytokine function, and alterations in the relative numbers of immune cell populations. In addition to these post- vs. preflight studies, some data have been produced in flight. However, these in vitro analyses have been less than satisfactory because of differences between in-flight and ground-control conditions. Recently, both the U.S. and Russian space programs have started collecting in-flight, in vivo, cell-mediated immunity data. These studies have confirmed that the human cell-mediated immune system is blunted during spaceflight.
Geostatistical prediction of flow-duration curves
NASA Astrophysics Data System (ADS)
Pugliese, A.; Castellarin, A.; Brath, A.
We present in this study an adaptation of Topological kriging (or Top-kriging), which makes the geostatistical procedure capable of predicting flow-duration curves (FDCs) in ungauged catchments. Previous applications of Top-kriging mainly focused on the prediction of point streamflow indices (e.g. flood quantiles, low-flow indices, etc.). In this study Top-kriging is used to predict FDCs in ungauged sites as a weighted average of standardised empirical FDCs through the traditional linear-weighting scheme of kriging methods. Our study focuses on the prediction of period-of-record FDCs for 18 unregulated catchments located in Central Italy, for which daily streamflow series with length from 5 to 40 yr are available, together with information on climate referring to the same time-span of each daily streamflow sequence. Empirical FDCs are standardised by a reference streamflow value (i.e. mean annual flow, or mean annual precipitation times the catchment drainage area) and the overall deviation of the curves from this reference value is then used for expressing the hydrological similarity between catchments and for deriving the geostatistical weights. We performed an extensive leave-one-out cross-validation to quantify the accuracy of the proposed technique, and to compare it to traditional regionalisation models that were recently developed for the same study region. The cross-validation points out that Top-kriging is a reliable approach for predicting FDCs, which can significantly outperform traditional regional models in ungauged basins.
Enhancing Team Performance for Long-Duration Space Missions
NASA Technical Reports Server (NTRS)
Orasanu, Judith M.
Success of exploration missions will depend on skilled performance by a distributed team that includes both the astronauts in space and Mission Control personnel. Coordinated and collaborative teamwork will be required to cope with challenging complex problems in a hostile environment. While thorough preflight training and procedures will equip creW'S to address technical problems that can be anticipated, preparing them to solve novel problems is much more challenging. This presentation will review components of effective team performance, challenges to effective teamwork, and strategies for ensuring effective team performance. Teamwork skills essential for successful team performance include the behaviors involved in developing shared mental models, team situation awareness, collaborative decision making, adaptive coordination behaviors, effective team communication, and team cohesion. Challenges to teamwork include both chronic and acute stressors. Chronic stressors are associated with the isolated and confined environment and include monotony, noise, temperatures, weightlessness, poor sleep and circadian disruptions. Acute stressors include high workload, time pressure, imminent danger, and specific task-related stressors. Of particular concern are social and organizational stressors that can disrupt individual resilience and effective mission performance. Effective team performance can be developed by training teamwork skills, techniques for coping with team conflict, intracrew and intercrew communication, and working in a multicultural team; leadership and teamwork skills can be fostered through outdoor survival training exercises. The presentation will conclude with an evaluation of the special requirements associated with preparing crews to function autonomously in long-duration missions.
Rashes and Exanthems on Long Duration Space Flights
NASA Technical Reports Server (NTRS)
Ilscus, L.S.; Johnston, S.L.; Moynihan, S.; Kerstman, E.L.; Marshall, G.D.
INTRODUCTION: As NASA expands its human space exploration to the Moon, Mars and beyond, it will be presented with many challenges, not the least of which will be dealing with medical conditions, which on earth are simple, but take on new levels of complexity in space habitats. Skin conditions exemplify this complexity. METHODS AND RESULTS: While skin conditions account for 7 % of outpatient presentations to a primary care provider in the United States, NASA Longitudinal Study of Astronaut Health (LSAH) database indicates that cutaneous manifestations are significantly prevalent on-orbit. Reviewing this data for US astronauts, there have been 90 total cases of skin rashes during 27.34 person-years of spaceflight, or 3.29 cases/person. Specifically, STS-1 though 114 had 56 cases, ISS Expeditions 1 though 13 had 7 cases, Mir had 4 cases, Skylab had 5 cases and the Apollo program had 18 cases. If there was a period of 24 hours or more between rashes in the same crewmember, this was counted as an additional case. DISCUSSION: This prevalence is likely due, in some part, to constraints of hygiene and to immunologic changes that occur. The stresses of microgravity and austere Earth environments such as the Antarctic, submarine and military deployments, no doubt, similarly contribute to cutaneous reactions; but the difference of the environments are significant enough to warrant further study and discussion. This paper will discuss rashes, exanthems, and cutaneous reactions in space habitats; it will address diagnosis, causation, mitigation and treatment of skin conditions seen on orbit, to date, with a look to anticipating what may be seen with larger crews on future extended duration expeditions.
A Gamma-Ray Bursts' Fluence-Duration Correlation
Istvan Horvath; Lajos G. Balazs; Peter Meszaros; Zsolt Bagoly; Attila Meszaros
We present an analysis indicating that there is a correlation between the fluences and the durations of gamma-ray bursts, and provide arguments that this reflects a correlation between the total emitted energies and the intrinsic durations. For the short (long) bursts the total emitted energies are roughly proportional to the first (second) power of the intrinsic duration. This difference in the energy-duration relationship is statistically significant, and may provide an interesting constraint on models aiming to explain the short and long gamma-ray bursts.
Hazard based models for freeway traffic incident duration.
Tavassoli Hojati, Ahmad; Ferreira, Luis; Washington, Simon; Charles, Phil
Assessing and prioritising cost-effective strategies to mitigate the impacts of traffic incidents and accidents on non-recurrent congestion on major roads represents a significant challenge for road network managers. This research examines the influence of numerous factors associated with incidents of various types on their duration. It presents a comprehensive traffic incident data mining and analysis by developing an incident duration model based on twelve months of incident data obtained from the Australian freeway network. Parametric accelerated failure time (AFT) survival models of incident duration were developed, including log-logistic, lognormal, and Weibul-considering both fixed and random parameters, as well as a Weibull model with gamma heterogeneity. The Weibull AFT models with random parameters were appropriate for modelling incident duration arising from crashes and hazards. A Weibull model with gamma heterogeneity was most suitable for modelling incident duration of stationary vehicles. Significant variables affecting incident duration include characteristics of the incidents (severity, type, towing requirements, etc.), and location, time of day, and traffic characteristics of the incident. Moreover, the findings reveal no significant effects of infrastructure and weather on incident duration. A significant and unique contribution of this paper is that the durations of each type of incident are uniquely different and respond to different factors. The results of this study are useful for traffic incident management agencies to implement strategies to reduce incident duration, leading to reduced congestion, secondary incidents, and the associated human and economic losses. PMID:23333698
Intensity-Duration Relation in the Bartlett-Lewis Rectangular Pulse Model
NASA Astrophysics Data System (ADS)
Ritschel, Christoph; Rust, Henning; Ulbrich, Uwe; Nķvir, Peter
For several hydrological modelling tasks precipitation time series with a high (sub-daily) resolution are indispensable. This data is, however, not always available and thus replaced by model data. A canonical class of stochastic models for sub-daily precipitation is the class of Poisson cluster processes, e.g. the Bartlett-Lewis rectangular pulse model (BLRPM). The BLRPM has been shown to be able to well reproduce certain characteristics found in observations. Our focus is on intensity-duration relationship which are of particular importance in the context of hydrological modelling. We analyse several high resolution precipitation time series (5min) from Berlin and derive empirical intensity-duration relations for several return levels of intensities (intensity-duration-frequency curves, IDF curves). In a second step, we investigate to what extend the variants of a BLRPM are able to reproduce these relations (i.e., the IDF curves) for different situations (e.g., seasons) and for the various return-levels of intensities. By means of a sensitivity study with the BLRPM, we investigate to what extend the ability to reproduce the intensity-duration relationships is related to certain relations between the model parameters. Such relations are typically useful to reduce the complexity of the model and thus robustify and facilitate parameter estimation.
Sleep Duration and Depressive Symptoms: A Gene-Environment Interaction
Watson, Nathaniel F.; Harden, Kathryn Paige; Buchwald, Dedra; Vitiello, Michael V.; Pack, Allan I.; Strachan, Eric; Goldberg, Jack
Objective: We used quantitative genetic models to assess whether sleep duration modifies genetic and environmental influences on depressive symptoms. Method: Participants were 1,788 adult twins from 894 same-sex twin pairs (192 male and 412 female monozygotic [MZ] pairs, and 81 male and 209 female dizygotic [DZ] pairs] from the University of Washington Twin Registry. Participants self-reported habitual sleep duration and depressive symptoms. Data were analyzed using quantitative genetic interaction models, which allowed the magnitude of additive genetic, shared environmental, and non-shared environmental influences on depressive symptoms to vary with sleep duration. Results: Within MZ twin pairs, the twin who reported longer sleep duration reported fewer depressive symptoms (ec = -0.17, SE = 0.06, P < 0.05). There was a significant gene ū sleep duration interaction effect on depressive symptoms (a'c = 0.23, SE = 0.08, P < 0.05), with the interaction occurring on genetic influences that are common to both sleep duration and depressive symptoms. Among individuals with sleep duration within the normal range (7-8.9 h/night), the total heritability (h2) of depressive symptoms was approximately 27%. However, among individuals with sleep duration within the low (< 7 h/night) or high (? 9 h/night) range, increased genetic influence on depressive symptoms was observed, particularly at sleep duration extremes (5 h/night: h2 = 53%; 10 h/night: h2 = 49%). Conclusion: Genetic contributions to depressive symptoms increase at both short and long sleep durations. Citation: Watson NF; Harden KP; Buchwald D; Vitiello MV; Pack AI; Stachan E; Goldberg J. Sleep duration and depressive symptoms: a gene-environment interaction. SLEEP 2014;37(2):351-358. PMID:24497663
Personal growth following long-duration spaceflight
NASA Astrophysics Data System (ADS)
Suedfeld, Peter; Brcic, Jelena; Johnson, Phyllis J.; Gushin, Vadim
IntroductionSalutogenesis and posttraumatic growth represent personal growth and improved functioning as a result of experiencing major challenging events. These developments are not simply resilience (a return to a baseline level of well-being), but positive change in such characteristics as self-understanding, relations with others, personal values, and life goals. Space agencies and space psychologists, primarily concerned with deleterious effects and their countermeasures, have not paid much attention to such beneficial long-term aftereffects of spaceflight. PurposeTo document what changes veterans of the Soviet/Russian space program report as a consequence of their experiences. MethodTwenty retired male cosmonauts Mir and/or ISS cosmonauts filled out relevant self-report questionnaires. Results: Although there was little change in the relative rankings of a list of values, the scale showed an overall increase in the rated importance of all personal values, although only the increase in Self-Direction reached statistical significance. Responses to one of two post-space growth questionnaires based on the Post-Traumatic Growth Inventory (PTGI) were compared to the means of two comparison groups: 152 first-time mothers, and 926 respondents who had experienced various forms of trauma. The cosmonauts reported higher scores on the dimension of New Possibilities when compared to the new mothers and the traumatized group, and higher scores on Personal Strength and Overall PTG compared to the latter. Respondents who had spent more than a year in space, and those who flew on both Mir and ISS, were the most likely to report positive change in the domain Appreciation of Life. The other post-space career questionnaire reflected major changes in Perceptions of the Earth and of Space, and increases on a number of other dimensions, including New Possibilities and Changes in Daily Life, with positive scores that significantly exceeded the original report. DiscussionIt appears that cosmonauts do experience various aspects of positive personal growth following their space flights. As long-duration missions are (and will remain) the norm, it is important for the space agencies and the voyagers themselves to develop a better understanding and possible enhancement of this phenomenon.
Forecasting final budget and duration of highway construction projects
Wichan Pewdum; Thammasak Rujirayanyong; Vanee Sooksatra
Purpose ¢ The purpose of this paper is to develop models to forecast final budget and duration of a highway construction project during construction stage. Design\\/methodology\\/approach ¢ Highway construction project data are collected and analyzed to find out factors affecting project final budget and duration before developing the forecasting models, research for which is based on the principle of Artificial
Theoretical duration and amplitude of an FM click
A. J. Rainal
The exact initial behavior of the probability density of the duration of an FM click in the case of an unmodulated carrier plus narrowband stationary Gaussian noise is presented. A simple Maxwell probability density is developed to approximate the probability density of the duration. The development leads to the conjecture that the Maxwell probability density is the exact limiting probability
Neuronal representation of duration discrimination in the monkey striatum
Chiba, Atsushi; Oshio, Ken-ichi; Inase, Masahiko
Functional imaging and lesion studies in humans and animals suggest that the basal ganglia are crucial for temporal information processing. To elucidate neuronal mechanisms of interval timing in the basal ganglia, we recorded single-unit activity from the striatum of two monkeys while they performed a visual duration discrimination task. In the task, blue and red cues of different durations (0.2¢2.0Āsec) were successively presented. Each of the two cues was followed by a 1.0Āsec delay period. The animals were instructed to choose the longer presented colored stimulus after the second delay period. A total of 498 phasically active neurons were recorded from the striatum, and 269 neurons were defined as task related. Two types of neuronal activity were distinguished during the delay periods. First, the activity gradually changed depending on the duration of the cue presented just before. This activity may represent the signal duration for later comparison between two cue durations. The activity during the second cue period also represented duration of the first cue. Second, the activity changed differently depending on whether the first or second cue was presented longer. This activity may represent discrimination results after the comparison between the two cue durations. These findings support the assumption that striatal neurons represent timing information of sensory signals for duration discrimination. PMID:25677545
Duration study for heating and air-conditioning design temperatures
Recently, abnormally cold winters and hot summers have generated interest in the duration of time that design temperature values have been equaled or exceeded. ETAC's Engineering Meteorology Section did a pilot study to examine temperature records for several military installations and give some insight into durations that may occur. The authors chose sites to represent different climatic regimes. For each
Competitive routing of virtual circuits with unknown duration
Baruch Awerbuch; Yossi Azart; Serge A. Plotkin; Orli Waarts
In this paper we present a strategy to route unknown duration virtual circuits in a highspeed communication network. Previous work on virtual circuit routing concentrated on the case where the call duration is known in advance. We show that by allowing O(logn) reroutes per call, we can achieve O(logn) competitive ratio with respect to the maximum load (congestion) for the
The multistate life table with duration?dependence
Douglas A. Wolf
A method for generalizing the multistate, or increment?decrement, life table to include rates which depend upon duration of exposure to risk, as well as upon age, is proposed. The method is built upon the linear approximation, called the linear integration hypothesis, developed mainly by Rogers and his colleagues. Although the use of rates indexed by duration categories leads to a
Communication apprehension and motivation as predictors of public speaking duration
Michael J. Beatty; Edmund C. Forst; Robert A. Stewart
Communication apprehension (CA) has attracted considerable attention in the research literature over the past fifteen years. The present study attempted to predict the duration of informative speeches using an interactive model employing CA scores and estimates of situational motivation. Results indicated that CA alone accounted for a significant but small proportion of variance in speech duration. However, a full regression
Duration of Sleep and ADHD Tendency among Adolescents in China
ERIC Educational Resources Information Center
Lam, Lawrence T.; Yang, L.
Objective: This study investigates the association between duration of sleep and ADHD tendency among adolescents. Method: This population-based health survey uses a two-stage random cluster sampling design. Participants ages 13 to 17 are recruited from the total population of adolescents attending high school in one city of China. Duration ofģ
A simple definition of the duration of strong earthquake ground motion based on the mean-square integral of motion has been presented. It is closely related to that part of the strong motion which contributes significantly to the seismic energy as recorded at a point and to the related spectral amplitudes. Correlations have been established between the duration of strong-motion acceleration,
10 CFR 52.61 - Duration of renewal.
Code of Federal Regulations, 2012 CFR
10 ? Energy ? 2 ? 2012-01-01 ? 2012-01-01 ? false ? Duration of renewal. ? 52.61 ? Section 52.61 ? Energy ? NUCLEAR REGULATORY COMMISSION (CONTINUED) ? LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS ? Standard Design Certifications ? ¦ 52.61 ? Duration of renewal. ? Each...
10 CFR 52.61 - Duration of renewal.
Code of Federal Regulations, 2013 CFR
10 ? Energy ? 2 ? 2013-01-01 ? 2013-01-01 ? false ? Duration of renewal. ? 52.61 ? Section 52.61 ? Energy ? NUCLEAR REGULATORY COMMISSION (CONTINUED) ? LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS ? Standard Design Certifications ? ¦ 52.61 ? Duration of renewal. ? Each...
Instrumental Variable Estimation of Treatment Effects for Duration Outcomes
Govert Bijwaard
In this article we propose and implement an instrumental variable estimation procedure to obtain treatment effects on duration outcomes. The method can handle the typical complications that arise with duration data of time-varying treatment and censoring. The treatment effect we define is in terms of shifting the quantiles of the outcome distribution based on the Generalized Accelerated Failure Time (GAFT)
Instrumental variable estimation of treatment effects for duration outcomes
G. E. Bijwaard
In this article we propose and implement an instrumental variable estimation procedure to obtain treatment effects on duration outcomes. The method can handle the typical complications that arise with duration data of time-varying treatment and censoring. The treatment effect we define is in terms of shifting the quantiles of the outcome distribution based on the Generalized Accelerated Failure Time (GAFT)
Resolving Over-constrainedTemporal Problems with Uncertain Durations
Williams, Brian C.
-constrained Temporal Problems with Uncertain Durations 11/46 Ę Duration: Sep 26th Ł Oct 17th. Ę Vessel: R/V Atlantis. Ę Location:Along the coast between SF and LA. Ę Objectives: Ł Find and sample methane seeps near the coast. Ł Locate and sample a 60 year-old DDT dumping site. Ł Recover and replace incubators on the seafloor. #12;A
Correcting Memory Improves Accuracy of Predicted Task Duration
Michael M. Roy; Scott T. Mitten; Nicholas J. S. Christenfeld
People are often inaccurate in predicting task duration. The memory bias explanation holds that this error is due to people having incorrect memories of how long previous tasks have taken, and these biased memories cause biased predictions. Therefore, the authors examined the effect on increasing predictive accuracy of correcting memory through supplying feedback for actual task duration. For Experiments 1
Depth-duration frequency of precipitation for Texas
Asquith, William H.
The U.S. Geological Survey, in cooperation with the Texas Department of Transportation, conducted a study of the depth-duration frequency of precipitation for Texas. Depth-duration frequency is an estimate of the depth of precipitation for a specified duration and frequency or recurrence interval. For this report, precipitation durations of 15, 30, and 60 minutes; 1, 2, 3, 6, 12, and 24 hours; and 1, 2, 3, 5, and 7 days were investigated. The recurrence intervals for the frequencies range from 2 to 500 years. The time series of precipitation annual maxima for 173 fifteen-minute, 274 hourly, and 865 daily National Weather Service precipitation stations with at least 10 years of record in Texas provide the basis of depth-duration frequency for each identified duration. In total, about 3,030; 10,160; and 38,120 cumulative years of record are available for the 15-minute, hourly, and daily stations, respectively. L-moment statistics of the precipitation annual maxima were calculated for each duration and for each station using unbiased L-moment estimators. The statistics calculated were the mean, L-scale, L-coefficient of variation, L-skew, and L-kurtosis. The mean for each station and duration was corrected for the bias associated with fixed-interval recording of precipitation. The generalized logistic distribution was determined, using L-moment ratio diagrams, as an appropriate probability distribution for modeling the frequency of annual maxima for durations of 15 minutes to 24 hours; whereas, the generalized extreme-value distribution was determined as appropriate for durations of 1 to 7 days. The location, scale, and shape parameters of the distributions for each duration and each station were calculated from the L-moments. These parameters were contoured using spatial interpolation, based on the geostatistical method of kriging, to produce 37 maps that depict the spatial variation and magnitude of each parameter. Contour maps of the shape parameter for the generalized extreme-value distribution for durations of 1 to 7 days are not presented; the root mean square errors of preliminary maps for 1- to 7-day shape parameters were not appreciably smaller than the statewide standard deviation. Therefore, a single statewide mean shape parameter was used for 1- to 7-day durations. The depth-duration frequency for any location in Texas can be estimated using the contour maps and the equation of the corresponding distribution.
Brugada syndrome (BS) and syncope: a complex therapeutic issue.
Merante, Alfonso; Gareri, Pietro; Bonacci, Elvira; Russo, Gaetano; Castagna, Alberto; Lacava, Roberto; Marigliano, Norma Maria; Gualtieri, Umberto; Condito, Anna Maria; Ruotolo, Giovanni
A 66 year-old man was brought to the emergency room (ER) for syncope and sphincter incontinence; syncope duration was about 15 min. Similar short duration episodes had been referred by his relatives during the last months, following small traumas; no seizures had been registered. Patient told he was affected with BS, having already been diagnosed 5 years before, after performing an electrocardiogram (ECG) highly suggestive for it. He had performed an electrophysiologic study, which had not shown any sustained ventricular arrhythmias after scheduled stimulation. This finding together to the lack of symptoms had suggested a conservative treatment, notwithstanding that familiar history documented his father's sudden death. Patient was also affected with hypertension and gastroesophageal reflux disease. Clinical examination did not suggest any significant findings. Laboratory tests, supra aortic Doppler ultrasound, electroencephalogram (EEG) and brain CT were normal. ECG showed sinus rhythm with a heart frequency of 82 bpm, QRS axis was normal, as well as atrioventricular conduction. ST coved-type elevation with right bundle branch block pattern and repolarization abnormalities were found. Holter ECG and Doppler echocardiography were also performed. The onset of syncope in presence of BS suggested the evaluation of this case report together with electrophysiolgists and neurologists. Therefore, an implantable cardioverter defibrillator (ICD) was implanted through left subclavian vein. He was discharged eight days after hospitalization, diagnosis was "Syncope in patient affected with BS, hypertension". Arrhythmogenic risk stratification is necessary; the indication for implanting this device is obvious in symptomatic patients, whereas it is controversial in patients presenting only ECG patterns of BS. In conclusion, the above mentioned case report rises remarkable diagnostic and therapeutic issues. The finding of BS in a patient with syncope indicates the opportunity of implanting a defibrillator and only clinical experience and common opinions may help doctors in taking the most appropriated, often difficult, decisions. PMID:22115873
What's in a face? Effects of stimulus duration and inversion on face processing in schizophrenia?
Butler, Pamela D.; Tambini, Arielle; Yovel, Galit; Jalbrzikowski, Maria; Ziwich, Rachel; Silipo, Gail; Kanwisher, Nancy; Javitt, Daniel C.
A number of studies show deficits in early-stage visual processing in schizophrenia. Deficits are also seen at more complex levels, such as ability to discriminate faces. This study investigated the ōface inversionö effect, which reflects intrinsic cortical processing within the ventral visual stream, as well as contrast sensitivity, which reflects low-level visual processing, in order to evaluate integrity of specific stages of face processing in schizophrenia. Patients with schizophrenia and controls discriminated between pairs of upright or inverted faces or houses that had been manipulated to differ in the shape of the parts or the spatial distance among parts. The duration threshold for above chance performance on upright stimuli was obtained for patients using a house discrimination task. Contrast sensitivity was assessed for gratings of three spatial frequencies ranging from 0.5 to 21 cycles/degree. Patients needed significantly longer time to obtain 70% correct for upright stimuli and showed decreased contrast sensitivity. Increased duration threshold correlated with reduced contrast sensitivity to low (magnocellular-biased) but not medium or high spatial frequency stimuli. Using increased durations, patients showed significant inversion effects that were equivalent to those of controls on the face part and spacing tasks. Like controls, patients did not show inversion effects on the house tasks. These findings show that patients have difficulty integrating visual information as shown by increased duration thresholds. However, when faces were presented at these longer duration thresholds, patients showed the same relative processing ability for upright vs. inverted faces as controls, suggesting preserved intrinsic processing within cortical face processing regions. Similar inversion effects for face part and spacing for both groups suggest that they are using the same holistic face processing mechanism. PMID:18450426
Leaf surface wetness duration measurements by radiogauge and electronic techniques
Barthakur, N.N.
Comparative measurements of leaf surface wetness duration were made by a beta-ray gauge and an electronic sensor under various wind conditions in the laboratory. Under certain conditions, surface wetness duration measured by the electronic sensor was about 35 minutes shorter than that by the beta-ray gauge. Fair agreement between the sensors at low wind speeds was achieved when the wire grid of the electronic sensor was mounted on a microscope cover glass. Realistic leaf surface wetness duration can be obtained with a beta-ray gauge as it utilizes the attached leaf surfaces rather than artificial ones used on the electronic sensor.
Volume-Duration-Frequencies for Ungaged Catchments in TexasĀ
Devulapalli, Ravi S.; Valdes, Juan B.
This report summarizes results from studies to determine relationships among the volume, duration and frequencies of floods in ungaged catchments in Texas. Methodologies were adopted for determining flood volumes at unregulated, non-urban catchments...
15 CFR 255.6 - Duration of fellowships.
Code of Federal Regulations, 2010 CFR
...STANDARDS AND TECHNOLOGY, DEPARTMENT OF COMMERCE FELLOWSHIPS AND RESEARCH ASSOCIATES FELLOWSHIPS IN LABORATORY STANDARDIZATION AND TESTING FOR QUALIFIED CITIZENS OF OTHER AMERICAN REPUBLICS ¦ 255.6 Duration of fellowships....
Consistent standard errors for semiparametric duration models with unobserved heterogeneity
Peter Bearse; Josķ Canals; Paul Rilstone
This paper uses the semiparametric approach of Bearse, Canals and Rilstone (1996) to estimate a duration model of strike lengths with unobserved heterogeneity. Consistent standard errors are reported and compared to traditional parametric estimates.
Analysis of the Swift Gamma-Ray Bursts duration
Horvath, I.; Veres, P. [Dept. of Physics, Bolyai Military University, H-1581 Budapest, POB 15 (Hungary); Balazs, L. G.; Kelemen, J. [Konkoly Observatory, H-l525 Budapest, POB 67 (Hungary); Bagoly, Z. [Dept. of Physics of Complex Systems, Eoetvoes University, H-1117 Budapest, Pazmany P. s. 1/A (Hungary); Tusnady, G. [Renyi Institute of Mathematics, Hungarian Academy of Sciences, H-1364 Budapest, POB 127 (Hungary)
Two classes of gamma-ray bursts have been identified in the BATSE catalogs characterized by durations shorter and longer than about 2 seconds. There are, however, some indications for the existence of a third type of burst. Swift satellite detectors have different spectral sensitivity than pre-Swift ones for gamma-ray bursts. Therefore it is worth to reanalyze the durations and their distribution and also the classification of GRBs. Using The First BAT Catalog the maximum likelihood estimation was used to analyzed the duration distribution of GRBs. The three log-normal fit is significantly (99.54% probability) better than the two for the duration distribution. Monte-Carlo simulations also confirm this probability (99.2%)
Vocalization frequency and duration are coded in separate hindbrain nuclei
Chagnaud, Boris P.; Baker, Robert; Bass, Andrew H.
Temporal patterning is an essential feature of neural networks producing precisely timed behaviours such as vocalizations that are widely used in vertebrate social communication. Here we show that intrinsic and network properties of separate hindbrain neuronal populations encode the natural call attributes of frequency and duration in vocal fish. Intracellular structure/function analyses indicate that call duration is encoded by a sustained membrane depolarization in vocal prepacemaker neurons that innervate downstream pacemaker neurons. Pacemaker neurons, in turn, encode call frequency by rhythmic, ultrafast oscillations in their membrane potential. Pharmacological manipulations show prepacemaker activity to be independent of pacemaker function, thus accounting for natural variation in duration which is the predominant feature distinguishing call types. Prepacemaker neurons also innervate key hindbrain auditory nuclei thereby effectively serving as a call-duration corollary discharge. We propose that premotor compartmentalization of neurons coding distinct acoustic attributes is a fundamental trait of hindbrain vocal pattern generators among vertebrates. PMID:21673667
Duration of immobility in salamanders, genus Plethodon (Caudata: Plethodontidae)
Dodd, C. Kenneth, Jr.
Immobility is a potentially important antipredator behavior in salamanders, especially for those posessing noxious skin secretions. The duration of immobility in 15 species of terrestrial salamanders (Plethodon) varied among species. Most salamanders (78.8%) became immobile when initially contacted under field conditions, and remained immobile from 1-180 s. Immobility duration was inversely correlated with substrate temperature and covaried with air temperature, but snout-vent level (SVL) had no effect on duration. Only immobility times of Plethodon shenandoah were significantly different from any other species. Substrate temperature, air temperature, SVL, and species accounted for only a small percentage of the variance (r2=0.09). The degree of disturbance received during a predator-prey encounter is probably more important than the subtle effects of temperature and SVL in determining immobility duration.
Performance and alertness of railroad engineers on long duration trips
Karnali, Leona D., 1978-
The present study investigated the performance and alertness of 8 healthy male participants between the age of 31 years and 65 years old in nighttime, long duration simulated train operation. Participants completed the ...
10 CFR 451.6 - Duration of incentive payments.
Code of Federal Regulations, 2014 CFR
...Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION RENEWABLE ENERGY PRODUCTION INCENTIVES ¦ 451.6 Duration of...payments under this part with respect to a qualified renewable energy facility for 10 consecutive fiscal...
20 CFR 336.2 - Duration of normal unemployment benefits.
Code of Federal Regulations, 2014 CFR
20 Employees' Benefits 1 2014-04-01 2012-04-01 true Duration of normal unemployment benefits. 336.2 Section 336.2 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD UNEMPLOYMENT...
20 CFR 336.2 - Duration of normal unemployment benefits.
Code of Federal Regulations, 2013 CFR
20 Employees' Benefits 1 2013-04-01 2012-04-01 true Duration of normal unemployment benefits. 336.2 Section 336.2 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD UNEMPLOYMENT...
49 CFR 385.117 - Duration of safety monitoring system.
Code of Federal Regulations, 2013 CFR
...2013-10-01 false Duration of safety monitoring system. 385.117 Section...Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY REGULATIONS SAFETY FITNESS...
32 CFR 552.93 - Permit deadline and duration.
Code of Federal Regulations, 2010 CFR
...THE ARMY MILITARY RESERVATIONS AND NATIONAL CEMETERIES REGULATIONS AFFECTING MILITARY RESERVATIONS Fort Lewis Land Use Policy ¦ 552.93 Permit deadline and duration. (a) Permits will be issued 0700-1900 hours daily and...
Mighty Eagle Scores Longest, Highest Flight Yet - Duration: 71 seconds.
The Ō??Mighty Eagle,Ō?Ø a NASA robotic prototype lander, reached its highest altitude and velocity -- and longest duration -- on Oct. 25 when it soared to a height of more than 150 feet during a fl...
Ectodysplasin signaling in cutaneous appendage development: Dose, duration and diversityĀ
Headon, Denis J.
The development of several skin appendages is guided by prenatal Ectodysplasin signalling. Cui et al. (this issue, 2009) report on the dose and duration of Ectodysplasin signalling required for the maintenance and morphogenesis ...
49 CFR 385.117 - Duration of safety monitoring system.
Code of Federal Regulations, 2014 CFR
...FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY REGULATIONS SAFETY FITNESS PROCEDURES Safety Monitoring System for Mexico-Domiciled Carriers ¦ 385.117 Duration of safety monitoring...
49 CFR 385.117 - Duration of safety monitoring system.
Code of Federal Regulations, 2012 CFR
...FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY REGULATIONS SAFETY FITNESS PROCEDURES Safety Monitoring System for Mexico-Domiciled Carriers ¦ 385.117 Duration of safety monitoring...
43 CFR 3140.5 - Duration of the lease.
Code of Federal Regulations, 2011 CFR
...Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Conversion of Existing Oil and Gas Leases and Valid Claims Based on Mineral Locations ¦ 3140.5 Duration of...
43 CFR 3140.5 - Duration of the lease.
Code of Federal Regulations, 2014 CFR
...Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Conversion of Existing Oil and Gas Leases and Valid Claims Based on Mineral Locations ¦ 3140.5 Duration of...
43 CFR 3140.5 - Duration of the lease.
Code of Federal Regulations, 2013 CFR
...Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Conversion of Existing Oil and Gas Leases and Valid Claims Based on Mineral Locations ¦ 3140.5 Duration of...
43 CFR 3140.5 - Duration of the lease.
Code of Federal Regulations, 2012 CFR
...Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Conversion of Existing Oil and Gas Leases and Valid Claims Based on Mineral Locations ¦ 3140.5 Duration of...
Analysis of extended-duration sortie missions. [Spacelab payload capabilities
NASA Technical Reports Server (NTRS)
Ring, R. C.; Lide, W. C.
Many Spacelab payloads could significantly benefit from an extension of the duration of sortie missions beyond the nominal seven days. However, longer sortie missions require the addition of Shuttle or Spacelab mission extension kits, which results in a significant reduction in allowable scientific payload weight. An analysis of extended-duration sortie missions was performed. Payload requirements and detailed descriptions of Shuttle and Spacelab baselines were the primary inputs to the analysis. Payload benefits from extended-duration missions were established by surveying payload requirements and interviewing discipline specialists. The net weight available to Spacelab payloads as a function of mission length was derived. The impacts on Shuttle and Spacelab to provide extended-duration mission support and the corresponding impacts on payloads were established. Several alternatives to baseline systems and operations were studied as possibilities to increase available payload weight.
36 CFR 223.31 - Duration of contracts.
Code of Federal Regulations, 2012 CFR
...Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS Timber Sale Contracts Contract Conditions and Provisions ¦ 223.31 Duration...
25 CFR 163.24 - Duration of timber contracts.
Code of Federal Regulations, 2010 CFR
...GENERAL FORESTRY REGULATIONS Forest Management and Operations ¦ 163.24 Duration of timber contracts. After the effective date of a forest product contract, unless otherwise...the estimated volume of timber purchased, shall be...
36 CFR 223.31 - Duration of contracts.
Code of Federal Regulations, 2011 CFR
...Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS Timber Sale Contracts Contract Conditions and Provisions ¦ 223.31 Duration...
36 CFR 223.31 - Duration of contracts.
Code of Federal Regulations, 2014 CFR
...Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS Timber Sale Contracts Contract Conditions and Provisions ¦ 223.31 Duration...
36 CFR 223.31 - Duration of contracts.
Code of Federal Regulations, 2013 CFR
...Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS Timber Sale Contracts Contract Conditions and Provisions ¦ 223.31 Duration...
22 CFR 709.6 - Suspension duration criteria.
Code of Federal Regulations, 2010 CFR
...709.6 Section 709.6 Foreign Relations OVERSEAS PRIVATE INVESTMENT CORPORATION ADMINISTRATIVE PROVISIONS FOREIGN CORRUPT PRACTICES ACT OF 1977 ¦ 709.6 Suspension duration criteria. Factors which the President may consider in...
7 CFR 3434.7 - Duration of certification.
Code of Federal Regulations, 2014 CFR
...Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND AGRICULTURE HISPANIC-SERVING AGRICULTURAL COLLEGES AND UNIVERSITIES CERTIFICATION PROCESS ¦ 3434.7 Duration of certification. (a) Except as provided in paragraphs (b)...
Speciation durations and Pleistocene effects on vertebrate phylogeography
Avise, John
Speciation durations and Pleistocene effects on vertebrate phylogeography John C. Avise* , De to evaluate Pleistocene phylogeographic eĪects and to estimate temporal spans of the speciation process and birds, Pleistocene conditions played an important role in initiating phylogeographic di
Duration Effects in Contingency Management Treatment of Methamphetamine Disorders
Roll, John M.; Chudzynski, Joy; Cameron, Jennifer M.; Howell, Donelle N.; McPherson, Sterling
The primary aim of this study was to determine whether different durations of contingency management (CM) in conjunction with psychosocial treatment produced different rates of abstinence among methamphetamine dependent individuals. Participants were randomized to one of four 16-week treatment conditions: standard psychosocial treatment or psychosocial treatment plus one of three durations of CM (one-month, two-month, or four-month). A total of 118 participants were randomized to the four treatment conditions. There were significant differences across treatment conditions for number of consecutive days of methamphetamine abstinence (p < 0.05). These differences were in the hypothesized direction, as participants were more likely to remain abstinent through the 16-week trial as CM duration increased. A significant effect of treatment condition (p < 0.05) and time (p < 0.05) on abstinence over time was also found. Longer durations of CM were more effective for maintaining methamphetamine abstinence. PMID:23708468
Memory and the experience of duration in retrospect.
Block, R A
Two experiments investigated the relationship between long-term memory for events occurring during an interval and the experience of duration of the interval in retrospect. In both, Ss attended to a sequence consisting of a standard, an experimental, and a second standard interval. Then unexpected comparative duration and memory judgments were requested. In Experiment I, either 30 or 60 unrelated words occurred during the 180-see experimental interval. When more words had occurred, judgments of duration of the experimental interval, judgments of number of words presented, and number of words recognized all increased, but free recall of words was unaffected. In Experiment II, 80 categorized words occurred during the 160-see experimental interval, with category instances in either blocked or random order. When words were blocked by category, judgments of duration of the experimental interval, free recall, and recognition all increased, but judgments of number of words were unaffected. Results were discussed in terms of Ornstein's (1969) "storage size" hypothesis. PMID:24214715
Personality and the prediction of short-duration emotional reactionsĀ
Sheese, Bradley E
Three converging studies (N=1413) presented initial evidence on the associations between personality dimensions and emotions (short-duration emotional reactions). We evaluated two distinct conceptual models of personality-emotion ...
25 CFR 163.24 - Duration of timber contracts.
Code of Federal Regulations, 2012 CFR
... 163.24 Section 163.24 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations ¦ 163.24 Duration of timber contracts. After the effective date...
25 CFR 163.24 - Duration of timber contracts.
Code of Federal Regulations, 2011 CFR
... 163.24 Section 163.24 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations ¦ 163.24 Duration of timber contracts. After the effective date...
25 CFR 163.24 - Duration of timber contracts.
Code of Federal Regulations, 2013 CFR
... 163.24 Section 163.24 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations ¦ 163.24 Duration of timber contracts. After the effective date...
42 CFR 61.38 - Duration of service fellowships.
Code of Federal Regulations, 2010 CFR
...38 Section 61.38 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING FELLOWSHIPS Service Fellowships ¦ 61.38 Duration of service fellowships. Initial...
14 CFR 65.92 - Inspection authorization: Duration.
Code of Federal Regulations, 2010 CFR
...AIRMEN CERTIFICATION: AIRMEN OTHER THAN FLIGHT CREWMEMBERS Mechanics ¦ 65.92 Inspection authorization: Duration. ...that authorization only while he holds a currently effective mechanic certificate with both a currently effective airframe...
14 CFR 65.92 - Inspection authorization: Duration.
Code of Federal Regulations, 2011 CFR
...AIRMEN CERTIFICATION: AIRMEN OTHER THAN FLIGHT CREWMEMBERS Mechanics ¦ 65.92 Inspection authorization: Duration. ...that authorization only while he holds a currently effective mechanic certificate with both a currently effective airframe...
14 CFR 65.92 - Inspection authorization: Duration.
Code of Federal Regulations, 2012 CFR
...AIRMEN CERTIFICATION: AIRMEN OTHER THAN FLIGHT CREWMEMBERS Mechanics ¦ 65.92 Inspection authorization: Duration. ...that authorization only while he holds a currently effective mechanic certificate with both a currently effective airframe...
14 CFR 65.92 - Inspection authorization: Duration.
Code of Federal Regulations, 2013 CFR
...AIRMEN CERTIFICATION: AIRMEN OTHER THAN FLIGHT CREWMEMBERS Mechanics ¦ 65.92 Inspection authorization: Duration. ...that authorization only while he holds a currently effective mechanic certificate with both a currently effective airframe...
14 CFR 65.92 - Inspection authorization: Duration.
Code of Federal Regulations, 2014 CFR
...AIRMEN CERTIFICATION: AIRMEN OTHER THAN FLIGHT CREWMEMBERS Mechanics ¦ 65.92 Inspection authorization: Duration. ...that authorization only while he holds a currently effective mechanic certificate with both a currently effective airframe...
7 CFR 922.67 - Duration of immunities.
Code of Federal Regulations, 2010 CFR
... AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE APRICOTS GROWN IN DESIGNATED COUNTIES IN WASHINGTON Order Regulating Handling Miscellaneous Provisions ¦ 922.67 Duration...
7 CFR 922.67 - Duration of immunities.
Code of Federal Regulations, 2011 CFR
... AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE APRICOTS GROWN IN DESIGNATED COUNTIES IN WASHINGTON Order Regulating Handling Miscellaneous Provisions ¦ 922.67 Duration...
Introduction to duration concepts: application to bank management
Meyers, Alison J.
INTRODUCTION TO DURATION CONCEPTS: APPLICATION TO BANK MANAGEMENT A Professional Paper by Alison J. Meyers Submitted to the College of Agriculture of Texas ASM University in partial fulfillment of the requirements for the degree of MASTER... OP AGRICULTURE May 1985 Agricultural Economics Agribanking INTRODUCTION TO DURATION CONCEPTS: APPLICATION TO BANK MANAGEMENT A Professional Paper by Alison J. Meyers prov as to style a content by: n Hopkin, irma , Advisory Committee David...
Particle Astrophysics in NASA's Long Duration Balloon Program
Gorham, Peter W
A century after Viktor Hess' discovery of cosmic rays, balloon flights still play a central role in the investigation of cosmic rays over nearly their entire spectrum. We report on the current status of NASA balloon program for particle astrophysics, with particular emphasis on the very successful Antarctic long-duration balloon program, and new developments in the progress toward ultra-long duration balloons.
Development of long-duration ballooning in Antarctica
Jones, W.V. (National Aeronautics and Space Administration, Code ES, Space Physics Division, Washington, DC 20546 (USA))
Following four successful long-duration test flights from Australia to South America, a new flight support system with global tracking, command, and telemetry capability is being developed to support long-duration balloon flights of relatively sophisticated instruments at both mid-latitudes and in Antarctica. The first test flight for the joint NASA-NSF program to support flights in Antarctica is scheduled from McMurdo in December 1989, with operational capability two years later.
Planning in Time: Windows and Durations for Activities and Goals
Steven A. Vere
A general purpose automated planner\\/scheduler is described which generates parallel plans to achieve goals with imposed time con-straints. Both durations and start time windows may be specified for sets of goal conditions. The parallel plans consist of not just actions but also of events (triggered by circumstances), inferences, and scheduled events (completely beyond the actor's control). Deterministic dura-tions of all
A long-duration propulsive lunar landing testbed
Krishna Shankar; Kevin Peterson; Heather Jones; Justin Moidel; William Whittaker
Affordable test articles for descent and landing are crucial for developing commercial lunar landing capability. To ensure successful lunar landing, flight software must be tested over mission-length durations on hardware exhibiting dynamics analogous to those of true flight articles. Energetic and structural constraints typically preclude affordable long- duration lander tests. This paper details a first-in-kind propulsive lunar lander testbed designed
Effects of stimulus duration on audio-visual synchrony perception.
Kuling, I A; van Eijk, R L J; Juola, J F; Kohlrausch, A
The integration of visual and auditory inputs in the human brain occurs only if the components are perceived in temporal proximity, that is, when the intermodal time difference falls within the so-called subjective synchrony range. We used the midpoint of this range to estimate the point of subjective simultaneity (PSS). We measured the PSS for audio-visual (AV) stimuli in a synchrony judgment task, in which subjects had to judge a given AV stimulus using three response categories (audio first, synchronous, video first). The relevant stimulus manipulation was the duration of the auditory and visual components. Results for unimodal auditory and visual stimuli have shown that the perceived onset shifts to relatively later positions with increasing stimulus duration. These unimodal shifts should be reflected in changing PSS values, when AV stimuli with different durations of the auditory and visual components are used. The results for 17 subjects showed indeed a significant shift of the PSS for different duration combinations of the stimulus components. Because the shifts were approximately equal for duration changes in either of the components, no net shift of the PSS was observed as long as the durations of the two components were equal. This result indicates the need to appropriately account for unimodal timing effects when quantifying intermodal synchrony perception. PMID:22821079
Head and Trunk Movement Control During Locomotion After Long-Duration Spaceflight
NASA Technical Reports Server (NTRS)
Bloomberg, Jacob J.; Paige, Gary D.; Mulavara, A. P.; McDonald, P. V.; Layne, C. S.; Merkle, L. A.; Kozlovskaya, I. B.; Paloski, William H. (Technical Monitor)
Exposure to the microgravity environment encountered during spaceflight induces adaptive alteration in sensorimotor function that leads to postflight disturbances in locomotor control. Head and trunk movement control plays a central role in maintaining gaze stability and in providing a stable reference system to permit spatial navigation in a complex and constantly varying environment. The goal of the present study was to investigate the effects of long-duration spaceflight (3-6 months) on head and trunk movement control during postflight terrestrial locomotion. Before and after spaceflight, subjects walked on a motorized treadmill while performing a challenging gaze stabilization task requiring number recognition. Head and trunk kinematic data were collected with a video-based motion analysis system. Analysis of roll, pitch and yaw head and trunk movements during treadmill walking revealed postflight alterations in head and trunk movement control in all three planes of motion. Subjects also experienced oscillopsia during postflight walking which led to impairment in performance of the number recognition task. These data indicate that exposure to long-duration space flight causes alteration in head and trunk movement control during postflight locomotion. These changes have implications for the control of gaze and maintenance of dynamic stability during walking after long-duration spaceflight.
Aerosol-induced signal in sunshine duration records: A review of evidences
NASA Astrophysics Data System (ADS)
Sanchez-Romero, Alejandro; Sanchez-Lorenzo, Arturo; Azorin-Molina, Cesar; Calb¾, Josep; Gonzßlez, Josep-Abel
Aerosols play a complex and crucial role in the Earth's radiation budget, by enhancing the absorption and scattering of incoming solar radiation. Consequently, knowledge of the interannual and decadal changes of the atmospheric turbidity induced by aerosols is fundamental for a better understanding of the climate variability and change since pre-industrial times. However, there is a little knowledge regarding changes in aerosol concentrations in the atmosphere on decadal time scales, especially before 1980s, when both ground-based platforms (spectrophotometers) and satellite-borne measurements were available. Nevertheless, sunshine duration observations may be affected by changes in atmospheric aerosol loading, therefore they may provide an adequate proxy measurement for turbidity from the late 19th century up to present. This work reviews publications reporting the suitability of the sunshine duration records measured by Campbell-Stokes instruments to detect changes in atmospheric turbidity, with special emphasis on decadal time scales. In addition, some possible directions for future research are also suggested, particularly pointing out that analyses based on sunshine duration measurements could be extended worldwide since the 1950s due to the availability of records; for some regions, these data are available since as far as the late 19th century.
Depth-Duration Frequency of Precipitation for Oklahoma
Tortorelli, Robert L.; Rea, Alan; Asquith, William H.
A regional frequency analysis was conducted to estimate the depth-duration frequency of precipitation for 12 durations in Oklahoma (15, 30, and 60 minutes; 1, 2, 3, 6, 12, and 24 hours; and 1, 3, and 7 days). Seven selected frequencies, expressed as recurrence intervals, were investigated (2, 5, 10, 25, 50, 100, and 500 years). L-moment statistics were used to summarize depth-duration data and to determine the appropriate statistical distributions. Three different rain-gage networks provided the data (15minute, 1-hour, and 1-day). The 60-minute, and 1-hour; and the 24-hour, and 1-day durations were analyzed separately. Data were used from rain-gage stations with at least 10-years of record and within Oklahoma or about 50 kilometers into bordering states. Precipitation annual maxima (depths) were determined from the data for 110 15-minute, 141 hourly, and 413 daily stations. The L-moment statistics for depths for all durations were calculated for each station using unbiased L-mo-ment estimators for the mean, L-scale, L-coefficient of variation, L-skew, and L-kur-tosis. The relation between L-skew and L-kurtosis (L-moment ratio diagram) and goodness-of-fit measures were used to select the frequency distributions. The three-parameter generalized logistic distribution was selected to model the frequencies of 15-, 30-, and 60-minute annual maxima; and the three-parameter generalized extreme-value distribution was selected to model the frequencies of 1-hour to 7-day annual maxima. The mean for each station and duration was corrected for the bias associated with fixed interval recording of precipitation amounts. The L-scale and spatially averaged L-skew statistics were used to compute the location, scale, and shape parameters of the selected distribution for each station and duration. The three parameters were used to calculate the depth-duration-frequency relations for each station. The precipitation depths for selected frequencies were contoured from weighted depth surfaces to produce maps from which the precipitation depth-duration-frequency curve for selected storm durations can be determined for any site in Oklahoma.
An Electroencephalographic Investigation of the Filled-Duration Illusion
Mitsudo, Takako; Gagnon, Caroline; Takeichi, Hiroshige; Grondin, Simon
The study investigated how the brain activity changed when participants were engaged in a temporal production task known as the ōfilled-duration illusion.ö Twelve right-handed participants were asked to memorize and reproduce the duration of time intervals (600 or 800?ms) bounded by two flashes. Random trials contained auditory stimuli in the form of three 20?ms sounds between the flashes. In one session, the participants were asked to ignore the presence of the sounds, and in the other, they were instructed to pay attention to sounds. The behavioral results showed that duration reproduction was clearly affected by the presence of the sounds and the duration of time intervals. The filled-duration illusion occurred when there were sounds; the participants overestimated the interval in the 600-ms interval condition with sounds. On the other hand, the participants underestimated the 800-ms interval condition without sounds. During the presentation of the interval to be encoded, the contingent negative variation (CNV) appeared around the prefrontal scalp site, and P300 appeared around the parieto-central scalp site. The CNV grew larger when the intervals contained the sounds, whereas the P300 grew larger when the intervals were 800?ms and did not contain the sounds. During the reproduction of the interval to be presented, the Bereitschaftspotential (BP) appeared over the fronto-central scalp site from 1000?ms before the participantsÆ response. The BP could refer to the decision making process associated with the duration reproduction. The occurrence of three event-related potentials (ERPs), the P300, CNV, and BP, suggests that the fronto-parietal area, together with supplementary motor area (SMA), is associated with timing and time perception, and magnitude of these potentials is modulted by the ōfilled-duration illusionö. PMID:22232577
A Twin Study of Sleep Duration and Body Mass Index
Watson, Nathaniel F.; Buchwald, Dedra; Vitiello, Michael V.; Noonan, Carolyn; Goldberg, Jack
Study Objective: To determine the relative importance of genetic and environmental contributions to the association between sleep duration and body mass index (BMI). Methods: Twins from the University of Washington Twin Registry, a community-based sample of U.S. twins, provided self-reported height and weight for BMI calculation and habitual sleep duration. A generalized estimating equation model evaluated the overall and within twin pair effects of sleep duration on BMI with and without stratification by twin zygosity. A structural equation model was used to assess genetic and non-genetic contributions to BMI and sleep duration. Results: The study sample included 1,224 twins comprised of 423 monozygotic, 143 dizygotic, and 46 indeterminate pairs. The mean age was 36.9 years; 69% were female. A multivariate adjusted analysis of all twins revealed an elevated mean BMI (26.0 kg/m2) in short sleeping twins (< 7 h/night) compared to twins sleeping 7¢8.9 h/night (BMI 24.8 kg/m2; p < 0.01). The within-twin pair analysis revealed similar results, with the short sleeping twins having a mean BMI of 25.8 kg/m2 compared to 24.9 kg/m2 for the 7¢8.9 h/night sleep duration group (p = 0.02). When restricted to monozygotic twins, the within-twin pair analysis continued to reveal an elevated BMI in the short sleeping twins (25.7 kg/m2) compared to the 7¢8.9 h/night reference group (24.7 kg/m2; p = 0.02). No differences in mean BMI were observed between the 7¢8.9 h/night reference group twins and longer sleeping twins (? 9 h/night) in the analysis of all twins, the overall within-twin pair analysis, or the within-twin pair analysis stratified by zygosity. The heritability of sleep duration was 0.31 (p = 0.08) and BMI 0.76 (p < 0.01). Bivariate genetic analysis revealed little evidence of shared genetics between sleep duration and BMI (p = 0.28). Conclusions: Short sleep was associated with elevated BMI following careful adjustment for genetics and shared environment. These findings point toward an environmental cause of the relationship between sleep duration and BMI. Citation: Watson NF; Buchwald D; Vitiello MV; Noonan C; Goldberg J. A twin study of sleep duration and body mass index. J Clin Sleep Med 2010;6(1):11-17. PMID:20191932
38 CFR 21.6070 - Basic duration of a vocational training program.
Code of Federal Regulations, 2011 CFR
...Basic duration of a vocational training program. 21.6070 Section 21.6070 Pensions...REHABILITATION AND EDUCATION Temporary Program of Vocational Training for Certain New...Basic duration of a vocational training program. (a) Basic duration of a...
Incident Duration Modeling Using Flexible Parametric Hazard-Based Models
Assessing and prioritizing the duration time and effects of traffic incidents on major roads present significant challenges for road network managers. This study examines the effect of numerous factors associated with various types of incidents on their duration and proposes an incident duration prediction model. Several parametric accelerated failure time hazard-based models were examined, including Weibull, log-logistic, log-normal, and generalized gamma, as well as all models with gamma heterogeneity and flexible parametric hazard-based models with freedom ranging from one to ten, by analyzing a traffic incident dataset obtained from the Incident Reporting and Dispatching System in Beijing in 2008. Results show that different factors significantly affect different incident time phases, whose best distributions were diverse. Given the best hazard-based models of each incident time phase, the prediction result can be reasonable for most incidents. The results of this study can aid traffic incident management agencies not only in implementing strategies that would reduce incident duration, and thus reduce congestion, secondary incidents, and the associated human and economic losses, but also in effectively predicting incident duration time. PMID:25530753
Driver sensitivity to brake pulse duration and magnitude.
Lee, J D; McGehee, D V; Brown, T L; Nakamoto, J
Adaptive cruise control (ACC) requires that the driver intervene in situations that exceed the capability of ACC. A brake pulse might provide a particularly compatible means of alerting the driver to situations in which the acceleration authority of the ACC has been exceeded. This study examined the sensitivity of the driver to brake pulses of five different amplitudes (0.01-0.025 g) and five different durations (50-800 ms). Drivers were sensitive to accelerations as low as 0.015 g. Pulse duration interacted with pulse amplitude, such that moderate duration pulses were more detectable than long and short duration pulses at intermediate levels of pulse amplitude. A power function with an exponent of 1.0 accounted for 99% of the variance in drivers' sensitivity to pulse amplitude; however, a power function with an exponent of 0.23 accounted for only 70% of the variance in drivers' sensitivity to pulse duration. These results can help designers create ACC algorithms and develop brake pulse warnings. PMID:17457744
Earth-space links and fade-duration statistics
NASA Technical Reports Server (NTRS)
Davarian, Faramaz
In recent years, fade-duration statistics have been the subject of several experimental investigations. A good knowledge of the fade-duration distribution is important for the assessment of a satellite communication system's channel dynamics: What is a typical link outage duration? How often do link outages exceeding a given duration occur? Unfortunately there is yet no model that can universally answer the above questions. The available field measurements mainly come from temperate climatic zones and only from a few sites. Furthermore, the available statistics are also limited in the choice of frequency and path elevation angle. Yet, much can be learned from the available information. For example, we now know that the fade-duration distribution is approximately lognormal. Under certain conditions, we can even determine the median and other percentiles of the distribution. This paper reviews the available data obtained by several experimenters in different parts of the world. Areas of emphasis are mobile and fixed satellite links. Fades in mobile links are due to roadside-tree shadowing, whereas fades in fixed links are due to rain attenuation.
Association between sleep duration and intelligence scores in healthy children.
Geiger, Anja; Achermann, Peter; Jenni, Oskar G
We examined the association between sleep behavior and cognitive functioning in 60 healthy children between 7 and 11 years of age under nonexperimental conditions. Intellectual abilities were assessed by the Wechsler Intelligence Scale for Children (4th edition) and sleep variables by questionnaires, actigraphy, and sleep diaries. Correlation analysis revealed a negative association between sleep duration on weekends and measures of intelligence (full-scale IQ, r = -.29; fluid IQ, r = -.36). The regression coefficient for sleep duration on weekends was -6.11 (SE = 2.09), indicating an increase of 6.11 points on fluid IQ scores for each hour of shorter sleep duration. Attention measures did not correlate with cognitive or sleep variables. Daytime sleepiness as a potential moderator of the relationship between sleep duration and cognitive performance was not related to cognitive or sleep variables. We conclude that children with higher daytime cognitive efficiency (reflected by higher intelligence scores) show increased nighttime efficiency (reflected by shorter sleep duration). In the light of the neural efficiency hypothesis, the current results argue for an extension of the original theory-referring not only to daytime but also to nighttime behavior. PMID:20604614
Competing risks mixture model for traffic incident duration prediction.
Li, Ruimin; Pereira, Francisco C; Ben-Akiva, Moshe E
Traffic incident duration is known to result from a combination of multiple factors, including covariates such as spatial and temporal characteristics, traffic conditions, and existence of secondary accidents but also the clearance method itself. In this paper, a competing risks mixture model is used to investigate the influence of clearance methods and various covariates on the duration of traffic incidents and predict traffic incident duration. The proposed mixture model considers the uncertainty in any of five clearance methods that occurred. The probability of the clearance method is specified in the mixture by using a multinomial logistic model. Three candidate distributions, namely, generalized gamma, Weibull, and log-logistic are tested to determine the most appropriate probability density function of the parametric survival analysis model. The unobserved heterogeneity is also incorporated into the mixture model in a way that allows parameters to vary across observations based on the three candidate distributions. The methods are illustrated with incident data from Singaporean expressways from January 2010 to December 2011. Regression analysis reveals that the probability of different clearance methods and the duration of traffic incidents are both significantly affected by various factors, such as traffic conditions and incident characteristics. Results show that the proposed mixture model is better than the traditional accelerated failure time model, and it predicts traffic incident duration with reasonable accuracy, as shown by the mean average percent error. PMID:25485730
Building a Shared Definitional Model of Long Duration Human Spaceflight
NASA Technical Reports Server (NTRS)
Orr, M.; Whitmire, A.; Sandoval, L.; Leveton, L.; Arias, D.
In 1956, on the eve of human space travel Strughold first proposed a simple classification of the present and future stages of manned flight that identified key factors, risks and developmental stages for the evolutionary journey ahead. As we look to optimize the potential of the ISS as a gateway to new destinations, we need a current shared working definitional model of long duration human space flight to help guide our path. Initial search of formal and grey literature augmented by liaison with subject matter experts. Search strategy focused on both the use of term long duration mission and long duration spaceflight, and also broader related current and historical definitions and classification models of spaceflight. The related sea and air travel literature was also subsequently explored with a view to identifying analogous models or classification systems. There are multiple different definitions and classification systems for spaceflight including phase and type of mission, craft and payload and related risk management models. However the frequently used concepts of long duration mission and long duration spaceflight are infrequently operationally defined by authors, and no commonly referenced classical or gold standard definition or model of these terms emerged from the search. The categorization (Cat) system for sailing was found to be of potential analogous utility, with its focus on understanding the need for crew and craft autonomy at various levels of potential adversity and inability to gain outside support or return to a safe location, due to factors of time, distance and location.
Effectiveness and duration of intramuscular antimotion sickness medications
NASA Technical Reports Server (NTRS)
Wood, C. D.; Stewart, J. J.; Wood, M. J.; Mims, M.
Motion sickness inhibits gastric motility, making the oral route ineffective for medications. The intramuscular route is an effective alternative. The rotating chair was used to produce the M 111 level of motion sickness on the Graybiel Symptom Scale. The intramuscular medications given 30 minutes before rotation were compared with placebo (saline, 1 mL) for effectiveness and duration in increasing the number of tolerated head movements. Average placebo number of head movements was 294. Promethazine 25 mg increased head movements by 78% (P < .05), with a duration of 12 hours. Scopolamine 0.2 mg increased head movements by 91% (P < .05), with a duration of 4 hours. The effect of caffeine 250 mg and ephedrine 25 mg was not significant. When combined with scopolamine, ephedrine produced an 32% additive effect. Scopolamine 0.08 mg, 0.1 mg, and 0.2 mg and also promethazine 12.5 mg and 25 mg were significant (P < .05). Promethazine appears to be the drug of choice for intramuscular use because of a longer duration and a high level of effectiveness. Scopolamine was of high effectiveness, but had a duration of 4 hours. It was eight times as potent by the intramuscular as by the oral route.
Earth-Space Links and Fade-Duration Statistics
NASA Technical Reports Server (NTRS)
Davarian, Faramaz
In recent years, fade-duration statistics have been the subject of several experimental investigations. A good knowledge of the fade-duration distribution is important for the assessment of a satellite communication system's channel dynamics: What is a typical link outage duration? How often do link outages exceeding a given duration occur? Unfortunately there is yet no model that can universally answer the above questions. The available field measurements mainly come from temperate climatic zones and only from a few sites. Furthermore, the available statistics are also limited in the choice of frequency and path elevation angle. Yet, much can be learned from the available information. For example, we now know that the fade-duration distribution is approximately lognormal. Under certain conditions, we can even determine the median and other percentiles of the distribution. This paper reviews the available data obtained by several experimenters in different parts of the world. Areas of emphasis are mobile and fixed satellite links. Fades in mobile links are due to roadside-tree shadowing, whereas fades in fixed links are due to rain attenuation.
The effect of context duration on Mandarin listeners' tone normalization.
Luo, Xin; Ashmore, Krista B
Tone normalization has been observed in Mandarin listeners, who contrastively adjust tone recognition using context pitch cues. This study tested the effect of context duration on Mandarin tone normalization. The target tones varied from Tone 1 (high-flat) to Tone 2 (mid-rising). The preceding phrase was modified to have different durations with 160- or 200-Hz mean fundamental frequencies (F0s). The results showed that the high-F0 context elicited significantly more Tone-2 responses than the low-F0 context, even when the contexts were 125 ms. The contrastive context effect saturated with the 250-ms contexts, indicating a 250-ms critical context duration for robust tone normalization. PMID:25096133
Fade durations in satellite-path mobile radio propagation
NASA Astrophysics Data System (ADS)
Schmier, Robert G.; Bostian, Charles W.
Fades on satellite to land mobile radio links are caused by several factors, the most important of which are multipath propagation and vegetative shadowing. Designers of vehicular satellite communications systems require information about the statistics of fade durations in order to overcome or compensate for the fades. Except for a few limiting cases, only the mean fade duration can be determined analytically, and all other statistics must be obtained experimentally or via simulation. This report describes and presents results from a computer program developed at Virginia Tech to simulate satellite path propagation of a mobile station in a rural area. It generates rapidly-fading and slowly-fading signals by separate processes that yield correct cumulative signal distributions and then combines these to simulate the overall signal. This is then analyzed to yield the statistics of fade duration.
Left ventricular wall thickness and disease duration in systemic sclerosis.
Heged³s, I.; Czirjßk, L.
Myocardial thickness, left ventricular functions, and right heart overloading were investigated in 80 patients with systemic sclerosis by echocardiography. Based on the left ventricular wall thickness, three groups were formed. Fifteen patients with asymmetrical left ventricular wall hypertrophy (Group 1) showed shorter mean disease duration with marked diastolic and mild systolic left ventricular functional impairment. The 25 patients with wall thinning (Group 3) had a slight increase in left ventricular diameters, impaired systolic functions and longer disease duration. Group 2 with wall thickness exhibited mixed changes. Patients with increased wall thickness tended to have a shorter disease duration than patients with wall thinning. Patients with systemic sclerosis showed systolic and diastolic function impairment as compared to the 18 control healthy individuals. Pericardial disease was found in 23 cases (28.7%). PMID:8321792
Hearing gestures, seeing music: vision influences perceived tone duration.
Schutz, Michael; Lipscomb, Scott
Percussionists inadvertently use visual information to strategically manipulate audience perception of note duration. Videos of long (L) and short (S) notes performed by a world-renowned percussionist were separated into visual (Lv, Sv) and auditory (La, Sa) components. Visual components contained only the gesture used to perform the note, auditory components the acoustic note itself. Audio and visual components were then crossed to create realistic musical stimuli. Participants were informed of the mismatch, and asked to rate note duration of these audio-visual pairs based on sound alone. Ratings varied based on visual (Lv versus Sv), but not auditory (La versus Sa) components. Therefore while longer gestures do not make longer notes, longer gestures make longer sounding notes through the integration of sensory information. This finding contradicts previous research showing that audition dominates temporal tasks such as duration judgment. PMID:17718367
Fade durations in satellite-path mobile radio propagation
NASA Technical Reports Server (NTRS)
Schmier, Robert G.; Bostian, Charles W.
Fades on satellite to land mobile radio links are caused by several factors, the most important of which are multipath propagation and vegetative shadowing. Designers of vehicular satellite communications systems require information about the statistics of fade durations in order to overcome or compensate for the fades. Except for a few limiting cases, only the mean fade duration can be determined analytically, and all other statistics must be obtained experimentally or via simulation. This report describes and presents results from a computer program developed at Virginia Tech to simulate satellite path propagation of a mobile station in a rural area. It generates rapidly-fading and slowly-fading signals by separate processes that yield correct cumulative signal distributions and then combines these to simulate the overall signal. This is then analyzed to yield the statistics of fade duration.
40 CFR 18.9 - Duration of Environmental Protection Research Fellowships.
Code of Federal Regulations, 2012 CFR
...false Duration of Environmental Protection Research Fellowships. 18...AGENCY GENERAL ENVIRONMENTAL PROTECTION RESEARCH FELLOWSHIPS AND SPECIAL...18.9 Duration of Environmental Protection Research Fellowships....
40 CFR 18.9 - Duration of Environmental Protection Research Fellowships.
Code of Federal Regulations, 2011 CFR
...false Duration of Environmental Protection Research Fellowships. 18...AGENCY GENERAL ENVIRONMENTAL PROTECTION RESEARCH FELLOWSHIPS AND SPECIAL...18.9 Duration of Environmental Protection Research Fellowships....
40 CFR 18.9 - Duration of Environmental Protection Research Fellowships.
Code of Federal Regulations, 2013 CFR
...false Duration of Environmental Protection Research Fellowships. 18...AGENCY GENERAL ENVIRONMENTAL PROTECTION RESEARCH FELLOWSHIPS AND SPECIAL...18.9 Duration of Environmental Protection Research Fellowships....
40 CFR 18.9 - Duration of Environmental Protection Research Fellowships.
Code of Federal Regulations, 2014 CFR
...false Duration of Environmental Protection Research Fellowships. 18...AGENCY GENERAL ENVIRONMENTAL PROTECTION RESEARCH FELLOWSHIPS AND SPECIAL...18.9 Duration of Environmental Protection Research Fellowships....
The changing landscape of cardiac pacing.
Barold, S Serge; Israel, Carsten W
A number of trials have shown that irrespective of baseline QRS duration, left ventricular (LV) dysfunction and heart failure are more common in patients with right ventricular (RV) than in those with biventricular (BiV) pacing. By contrast, preliminary results of the BIOPACE trial (follow-up 5.6Āyears) yielded a disappointing comparison of RV vs. BiV pacing. Pacemaker-induced cardiomyopathy (PIC) may occur in patients with normal and abnormal LV ejection fractions (LVEF) and tends to occur if there is RV pacing more than 40?% of the time. Yet, some pacemaker-dependent patients do not develop LV dysfunction. PIC can be improved in about two thirds of patients by upgrading to a BiV system and the results are comparable to de novo BiV pacing in patients with a wide QRS complex. The findings of the BLOCK HF trial (2013) suggested that patients requiring pacing virtually 100?% of the time might benefit from BiV pacing irrespective of the LVEF (50?%), manifestations of heart failure, QRS duration, or functional class. These characteristics would generate many patients for BiV pacing. However, these recommendations should now be weighed against a more conservative approach based on the recently announced results of the BIOPACE trial. Organizational guidelines recommend BiV pacing for bradycardia irrespective of QRS duration for patients with LVEF 35?%. At this time, BiV pacing for antibradycardia therapy (irrespective of QRS duration) has to be individualized in the setting of a normal or decreased LVEF (>?35?%) and according to the expected percentage of RV pacing. The benefit of BiV pacing should be considered against procedural complications, which are more frequent than with traditional RV pacing. PMID:25492587
Building a Shared Definitional Model of Long Duration Human Spaceflight
NASA Technical Reports Server (NTRS)
Arias, Diana; Orr, Martin; Whitmire, Alexandra; Leveton, Lauren; Sandoval, Luis
Objective: To establish the need for a shared definitional model of long duration human spaceflight, that would provide a framework and vision to facilitate communication, research and practice In 1956, on the eve of human space travel, Hubertus Strughold first proposed a "simple classification of the present and future stages of manned flight" that identified key factors, risks and developmental stages for the evolutionary journey ahead. As we look to new destinations, we need a current shared working definitional model of long duration human space flight to help guide our path. Here we describe our preliminary findings and outline potential approaches for the future development of a definition and broader classification system
Concept definition for an extended duration orbiter ECLSS
NASA Technical Reports Server (NTRS)
Brose, H.
Extending the seven-day Shuttle Orbiter baseline mission requires an evaluation of the Environmental Control and Life Support (ECLS) System in order to determine those changes necessary or desirable so that the Orbiter payload capability will not be seriously compromised. The ECLSS requirements and subsystem options for extended duration Orbiter missions are defined. Each major ECLS subsystem was examined, and potential methods of extending the mission capability were studied. The mission evaluated most extensively for this effort was a 30 day mission with a crew size of seven men. However, missions up to 90 days duration with crew sizes of three to ten men were also examined.
Duration of liquid water habitats on early Mars
NASA Astrophysics Data System (ADS)
McKay, C. P.; Davis, W. L.
The duration of ice-covered lakes after the initial freezing of the early Mars is presently estimated via a climate model whose critical parameter is the existence of peak seasonal temperatures above freezing, and in which the variability of insolation is included. Under conditions in which meltwater was supplied by an ice source, it is found that water habitats could have been maintained under relatively thin ice sheets for as many as 700 million years after the onset of below-freezing global temperatures. The duration of such habitats on the early Mars therefore exceeds the upper limit of the time envisioned for the emergence of aquatic life on earth.
Atom interferometry using ?-kicked and finite-duration pulse sequences
NASA Astrophysics Data System (ADS)
Daszuta, Boris; Andersen, Mikkel F.
We investigate an atom interferometer in which large momentum differences between the arms are obtained by using quantum resonances in the atom-optics ?-kicked rotor. The interferometer can potentially measure the Talbot time (from which h/m can be deduced) and the local gravitational field or can serve as a narrow velocity filter. We present an analytical analysis in the short pulse limit and a numerical investigation for finite pulse durations. The sensitivity of the interferometer is improved by a moderate violation of the short pulse limit. Remarkably simple relations predict the optimal pulse duration and the sensitivity of the interferometer.
Cognitive Assessment in Long-Duration Space Flight
NASA Technical Reports Server (NTRS)
Kane, Robert; Seaton, Kimberly; Sipes, Walter
This slide presentation reviews the development and use of a tool for assessing spaceflight cognitive ability in astronauts. This tool. the Spaceflight Cognitive Assessment Tool for Windows (WinSCAT) has been used to provide ISS flight surgeons with an objective clinical tool to monitor the astronauts cognitive status during long-duration space flight and allow immediate feedback to the astronaut. Its use is medically required for all long-duration missions and it contains a battery of five cognitive assessment subtests that are scheduled monthly and compared against the individual preflight baseline.
Kv3 potassium channels control the duration of different arousal states by distinct stochastic and clock-like mechanisms.
Joho, Rolf H; Marks, Gerald A; Espinosa, Felipe
Sleep-wake behavior is tightly controlled in many animal species, suggesting genetically encoded, homeostatic control mechanisms that determine arousal-state dynamics. We reported that two voltage-gated potassium channels, Kv3.1 and Kv3.3, control sleep in wild-type and Kv3-mutant mice. Compared with wild-type (WT), homozygous double mutants (DKO) that lack these channels sleep 40% less in the light and 22% less in the dark. To understand how the lack of these channels affects sleep, we analysed arousal-state changes during the light period where the differences are greatest between WT and DKO. We determined the kinetic complexity of each arousal state from the episode durations of wakefulness, slow-wave sleep and rapid eye movement sleep (REMS). Based on the number of exponential components in episode-duration histograms, WT and DKO mice have several kinetically distinct states of wakefulness, and these states are longer in duration in DKO. For slow-wave sleep, WT mice have a single slow-wave sleep (SWS) state in contrast to DKO mice, which show two distinct SWS states, one that is 60% shorter than that in WT and a second that is similar in duration. Both WT and DKO mice have two kinetically distinct REMS states. DKO mice show an 84% reduction in the frequency of short REMS episodes (<45 s) without any change in the occurrence of long REMS episodes (>60 s). In contrast to the stochastic control of episode durations of wakefulness and SWS, the durations of both REMS states are normally distributed, indicating that the underlying control processes are fundamentally different. PMID:16553620
Amplitude and Duration Interdependence in the Perceived Intensity of Complex Tactile Signals
Hayward, Vincent
msec [8, 13]. Similarly, the sensation of pain evoked by electrical stimulation of teeth [12] is more intense if the stimulation is presented for a longer time. In vision, a positive and approximate power law the auditory system, transients presented to the skin must last 5 to 10 times longer than those presented
Temporal Context in Concurrent Chains: I. Terminal-Link Duration
ERIC Educational Resources Information Center
Grace, Randolph C.
Two experiments are reported in which the ratio of the average times spent in the terminal and initial links ("Tt/Ti") in concurrent chains was varied. In Experiment 1, pigeons responded in a three-component procedure in which terminal-link variable-interval schedules were in constant ratio, but their average duration increased across componentsģ
Duration of spermatogenesis in the bullfrog (Lithobates catesbeianus).
Segatelli, T M; Batlouni, S R; Franńa, L R
The bullfrog (Lithobates catesbeianus) has substantial economic importance and has also been used as an experimental model for biological studies in the fields of pharmacology, medicine, and reproductive biology, especially studies addressing gametogenesis. However, there is a lack of comprehensive information in the literature regarding testis structure and function in this amphibian. The main objective of the current study was to estimate the duration of the various phases of spermatogenesis in this vertebrate. Sixteen sexually mature bullfrogs received an intracoelomic administration of tritiated thymidine. Testes were analyzed at various times between 1h and 33 d after administration to detect the most advanced germ cell types labeled at each interval, as well as labeled preleptotene spermatocytes, which presumably originated from spermatogonial stem cells. The duration of the spermatogonial, spermatocytic, and spermiogenic phases of spermatogenesis in the bullfrog were approximately 18, 14, and 8 d, respectively. Thus, the total duration of the spermatogenesis process from early spermatogonia through to spermatozoa was 40 d in this species, similar to that of most previously investigated mammalian species. To our knowledge, this is the first reliable report on the duration of the full spermatogenic process in any amphibian species. These findings will be very useful for tracking the pace of germ cells in studies involving spermatogonial transplantation in lower vertebrates. PMID:19683337
FIREONE/FIRETWO fire duration and severity calculation software
Larson, G.F.
This software package provides a worksheet environment for calculating fire duration and severity based on the method outlined by T.J. Harmathy as presented in his two part paper on compartment fires. This software is intended to aid engineers in designing facilities, ventilation systems, and process systems by allowing combustible loading ''what-ifs'' to be evaluated.
Oliver, Douglas L.
DIABETES MEDICATIONS: INSULIN INSULIN TYPE & DURATION OF ACTION NAMES ACTION Rapid-acting insulin Short-acting insulin Intermediate-acting insulin Long-acting insulin Mixed insulin Insulin Lispro (Humalog «), Insulin Aspart (Novolog «), Insulin Glulisine (Apidra «) Insulin Regular (Humulin R«, Novolin
Duration or Disadvantage? Exploring Nativity, Ethnicity, and Health in Midlife
Jacqueline L. Angel; Cynthia J. Buckley; Art Sakamoto
Objectives . This study examined nativity as a risk factor for poor physical and emotional health for an ethnically di- verse population making the transition into retirement. The authors addressed whether the health disadvantage observed for immigrants lessens with increased time spent in the country (supporting theories of assimilation) or increases with duration of residence (supporting theories of cumulative disadvantage).
Duration Test Report for the Entegrity EW50 Wind Turbine
Smith, J.; Huskey, A.; Jager, D.; Hur, J.
This report summarizes the results of a duration test that NREL conducted on the Entegrity EW50 wind turbine. This test was conducted in accordance with the International Electrotechnical Commissions' (IEC) standard, Wind Turbine Generator System Part 2: Design requirements for small wind turbines, IEC 61400-2 Ed.2.0, 2006-03.
Cyclostratigraphic and magnetostratigraphic constraints on the duration of the CAMP
P. E. Olsen; D. V. Kent
The duration of what may be the largest known flood basalt, the Central Atlantic Magmatic Province (CAMP), has major implications for the magmatic processes intimately related to one of the largest known continental rift provinces formed just antecedent to the break-up of central Pangea. While the reported scatter in radiometric dates from the CAMP has been decreasing in recent years
Recent activities for long duration flight systems in Japan
NASA Astrophysics Data System (ADS)
Nishimura, J.
For the feasibility studies of the long duration balloon systems in recent times in Japan, the forces was on following items. Ģ An analysis to utilize the Pumpkin Balloons for the over pressurized balloons, and to develop the simple automatic gas pressure control systems for the long duration flights. Ģ Test flights by the balloon group of the Institute of Space and Astronautical Science (ISAS) to see the performance of the balloons of new films of EVAL (Ethylene-Vinyl-Alcohol) having strong absorption bands of the infra-red between 7-14 microns. We expect that this absorption prevents the cooling of the lifting gas after the sun-sets, and thus save the ballast consumption. Ģ A sea recovery system beyond 100-200 km from the Pacific coast by using helicopters with ARGOS/GPS. The situation would be applicable to the sea recovery of payloads after the long duration flights at the turn-around period launched from Sanriku Balloon Center. The flight performances have already been proved in the 1975 and 77 achieving the duration of 55, 65, 80 hrs keeping the locations of payloads within 200 km from the sea coast. Ģ Studies on the high altitude balloons with thin polyethylene films are also reported in this paper.
Human factors in long-duration space flight
NASA Technical Reports Server (NTRS)
A study, covering the behavioral, psychological, physiological, and medical factors of long duration manned space flight, is presented. An attempt was made to identify and resolve major obstacles and unknowns associated with such a flight. The costs and maintenance of the spacecraft system are also explored.
Duration of Voluntary Breath Holding and Blood Parameters
L. I. Irzhak; P. V. Polyakov
Stange's and Genci's functional tests performed at rest and during exercise and blood tests have shown that the duration of voluntary breath holding depends on appearance in the blood of hypoxia, hypercapnia, and acidosis signs only after the influence of fatigue of respiratory muscles and respiratory center has become insufficient.
Tsunami early warning using earthquake rupture duration Anthony Lomax1
Rawlinson, Nick
Tsunami early warning using earthquake rupture duration Anthony Lomax1 and Alberto Michelini2] Effective tsunami early warning for coastlines near a tsunamigenic earthquake requires notification within 5, greater than about 50 s. Here we show that T0 gives more information on tsunami importance than moment
28 CFR 17.24 - Duration of classification.
Code of Federal Regulations, 2010 CFR
(a) At the time of original classification, original classification authorities shall attempt to establish a specific date or event for declassification not more than 10 years from the date of the original decision based on the duration of the national security sensitivity of the...
CRISP: A Computational Model of Fixation Durations in Scene Viewing
ERIC Educational Resources Information Center
Nuthmann, Antje; Smith, Tim J.; Engbert, Ralf; Henderson, John M.
Eye-movement control during scene viewing can be represented as a series of individual decisions about where and when to move the eyes. While substantial behavioral and computational research has been devoted to investigating the placement of fixations in scenes, relatively little is known about the mechanisms that control fixation durations.ģ
TITLE: Wireless Multimedia Architectures and Applications DURATION: Half day
Furht, Borko
efforts to establish a wireless infrastructure, including declaring a new wireless spectrum, building newSEMINAR TITLE: Wireless Multimedia Architectures and Applications DURATION: Half day INSTRUCTOR: Dr is to link present "wireless realities" to the future of technology. It should bring to participants 21st
The effects of odor and body posture on perceived duration
Schreuder, Eliane; Hoeksma, Marco R.; Smeets, Monique A. M.; Semin, G³n R.
This study reports an examination of the internal clock model, according to which subjective time duration is influenced by attention and arousal state. In a time production task, we examine the hypothesis that an arousing odor and an upright body posture affect perceived duration. The experimental task was performed while participants were exposed to an odor and either sitting upright (arousing condition) or lying down in a relaxing chair (relaxing condition). They were allocated to one of three experimental odor conditions: rosemary (arousing condition), peppermint (relaxing condition), and no odor (control condition). The predicted effects of the odors were not borne out by the results. Self-reported arousal (SRA) and pleasure (PL) states were measured before, during (after each body posture condition) and postexperimentally. Heart rate (HR) and skin conductance were measured before and during the experiment. As expected, odor had an effect on perceived duration. When participants were exposed to rosemary odor, they produced significantly shorter time intervals than in the no odor condition. This effect, however, could not be explained by increased arousal. There was no effect of body posture on perceived duration, even though body posture did induce arousal. The results do not support the proposed arousal mechanism of the internal clock model. PMID:24567718
Estimating weather impact on the duration of construction activities
Osama Moselhi; Daji Gong; Khaled El-Rayes
Weather conditions can have an adverse impact on the duration and cost of construction activities. Quantifying this impact is, clearly, valuable to contractors for preparing realistic schedules, cost estimates, and reliable bids. Productivity loss due to the impact of weather on construction activities can be either partial or complete; partial loss is generally attributed to reduced labor productivity and complete
School of Agricultural Sciences and Veterinary Medicine Course Location Duration
Schenato, Luca
School of Agricultural Sciences and Veterinary Medicine Course Location Duration (years) Admission Places for non-EU students (total) Places for Chinese students Veterinary Medicine Legnaro (PD) 5 limited Places for non-EU students (total) Places for Chinese students Chemistry and pharmaceutical Techniques
43 CFR 1784.1 - Establishment, duration, termination, and renewal.
Code of Federal Regulations, 2012 CFR
43 ? Public Lands: Interior ? 2 ? 2012-10-01 ? 2012-10-01 ? false ? Establishment, duration, termination, and renewal. ? 1784.1 ? Section 1784.1 ? Public Lands: Interior ? Regulations Relating to Public Lands (Continued) ? BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR ? GENERAL...
43 CFR 1784.1 - Establishment, duration, termination, and renewal.
Code of Federal Regulations, 2014 CFR
43 ? Public Lands: Interior ? 2 ? 2014-10-01 ? 2014-10-01 ? false ? Establishment, duration, termination, and renewal. ? 1784.1 ? Section 1784.1 ? Public Lands: Interior ? Regulations Relating to Public Lands (Continued) ? BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR ? GENERAL...
Experimental short-duration techniques. [gas turbine engine tests
NASA Technical Reports Server (NTRS)
Dunn, Michael G.
Short-duration facilities used for gas turbine studies are described. Data recording techniques; and instruments (thin-film heat flux gages, high-frequency response pressure measurements, total temperature probes, measurement of rotor tip speed, active measurement of tip clearance) are presented.
Impact of Breastfeeding Duration on Age at Menarche
Al-Sahab, Ban; Adair, Linda; Hamadeh, Mazen J.; Ardern, Chris I.; Tamim, Hala
The study aims to assess the relation between breastfeeding duration and age at menarche. Analysis was based on a cohort of 994 Filipino girls born in 1983¢1984 and followed up from infancy to adulthood by the Cebu Longitudinal Health and Nutrition Survey. The main outcome was self-reported age at menarche. Cox regression was used to investigate the relation between duration of exclusive and any breastfeeding with age at menarche with adjustment sequentially for specific sets of known socioeconomic, maternal, genetic, and prenatal confounders. The estimated median of age at menarche was 13.08 years. After adjustment for potential confounders of the association of breastfeeding with age at menarche, exclusive breastfeeding duration retained an independent and significant association with age at menarche. An increase in 1 month of exclusive breastfeeding decreases the hazard of attaining earlier menarche by 6% (hazard ratio = 0.94, 95% confidence interval: 0.90, 0.98). Any breastfeeding duration was not associated with age at menarche. Although this is the first longitudinal study that reveals a negative association between exclusive breastfeeding and early menarche, the relation is still elusive. Further longitudinal studies within different contexts are warranted to assess the generalizability of these findings. PMID:21430189
Duration Models and Proportional Hazards in Political Science
Janet M. Box-steffensmeier; Christopher J. W. Zorn
In recent years political scientists have increasingly adopted a wide range oftechniques for modeling duration data. A key assumption of all these approaches isthat the hazard ratios (i.e., the conditional relative risks across substrata) areproportional to one another, and that this proportionality is maintained over time.Estimation of proportional hazards (PH) models when in fact hazards are nonproportionalresults in coefficient biases
Budgeted Optimization with Concurrent Stochastic-Duration Experiments
Fern, Xiaoli Zhang
Budgeted Optimization with Concurrent Stochastic-Duration Experiments Javad Azimi, Alan Fern formulations assume that experiments are selected one at a time with a limited total number of experiments formulation with the following important extensions: 1) allowing for concurrent experiments; 2) allowing
The Long Duration Exposure Facility (LDEF). Mission 1 Experiments.
ERIC Educational Resources Information Center
Clark, Lenwood G., Ed.; And Others
The Long Duration Exposure Facility (LDEF) has been designed to take advantage of the two-way transportation capability of the space shuttle by providing a large number of economical opportunities for science and technology experiments that require modest electrical power and data processing while in space and which benefit from postflightģ
Active shielding for long duration interplanetary manned missions
Piero Spillantini
For long duration interplanetary manned missions the protection of astronauts from cosmic radiation is an unavoidable problem that has been considered by many space agencies. In Europe, during 2002¢2004, the European Space Agency supported two research programs on this thematic: one was the constitution of a dedicated study group (on the thematic æShielding from cosmic radiation for interplanetary missions: active
Resolving Over-constrained Temporal Problems with Uncertain Durations
Williams, Brian C.
/52 Ę Duration: Sep 26th Ł Oct 17th. Ę Vessel: R/V Atlantis. Ę Location:Along the coast between SF and LA. Ę Objectives: Ł Find and sample methane seeps near the coast. Ł Locate and sample a 60 year-old DDT dumping
Characterizing Determinants of Risk: Concentration, Duration, and Timing of Exposure
An ongoing challenge in human health risk assessment is to determine the best approach for characterizing the risk from real-world exposures. Three major determinants characterize exposure: concentration (how much), duration (the frequency and how long), and critical timing (whe...
A new duration modeling approach for Mandarin speech
Sin-horng Chen; Wen-hsing Lai; Yih-ru Wang
In this paper, a new duration modeling approach for Mandarin speech is proposed. It explicitly takes several major af- fecting factors as multiplicative companding factors (CFs) and esti- mates all model parameters by an EM algorithm. Besides, the three basic Tone 3 patterns (i.e., full tone, half tone and sandhi tone) are also properly considered via using three different CFs
Analysis of syllable duration models for Mandarin speech
Wen-Hsing Lai; Sin-Homg Chen
In this paper, the multiplicative syllable duration model proposed previously for Mandarin speech is extended in some aspects. First, the three basic Tone 3 patterns (i.e., full tone, half tone and sandhi tone) are properly considered via using three different companding factors (CFs) to separate their affections. Second, the CFs of the model are analyzed in detail. Third, the syllable
PhD Studentship in Soil Biogeochemistry Duration: 3 Years
Stell, John
methods including soil incubation, experimental manipulation and subsequent sampling for N speciation background in environmental science and an interest in soil biogeochemistry. Field work may involve samplingPhD Studentship in Soil Biogeochemistry Duration: 3 Years Application Deadline: July 10, 2014
Practitioner Empathy and the Duration of the Common Cold
Rakel, David P.; Hoeft, Theresa J.; Barrett, Bruce P.; Chewning, Betty A.; Craig, Benjamin M.; Niu, Min
Objective To assess the relationship of empathy in medical consultations to subsequent cold outcomes. Methods 350 subjects, ?12 years of age received either a standard or enhanced physician visit as part of a randomized controlled trial. The patient-scored Consultation and Relational Empathy (CARE) questionnaire assessed practitioner-patient interaction, especially empathy. Cold severity and duration were assessed from twice daily symptom reports. Nasal wash was performed to measure the immune cytokine IL-8. Results 84 individuals reported perfect (score of 50) CARE scores. They tended to be older with less education, but reported similar health status, quality of life, and levels of optimism. In those with perfect CARE scores, cold duration was shorter (mean 7.10 days vs. 8.01 days, p=0.032), and there was a trend towards reduced severity (mean AUC 240.40 vs. 284.49, p=0.118). After accounting for possible confounding variables, cold severity and duration were significantly lower in those reporting perfect CARE scores (p=0.037 and p=0.017 respectively). In these models, a perfect score also correlates with a larger increase in IL-8 levels (p=0.015). Conclusions Clinician empathy, as perceived by patients with the common cold, significantly predicts subsequent duration and severity of illness and is associated with immune system changes. PMID:19582635
Functional connectivity homogeneity correlates with duration of temporal lobe epilepsy.
Haneef, Zulfi; Chiang, Sharon; Yeh, Hsiang J; Engel, Jerome; Stern, John M
Temporal lobe epilepsy (TLE) is often associated with progressive changes to seizures, memory, and mood during its clinical course. However, the cerebral changes related to this progression are not well understood. Because the changes may be related to changes in brain networks, we used functional connectivity MRI (fcMRI) to determine whether brain network parameters relate to the duration of TLE. Graph theory-based analysis of the sites of reported regions of TLE abnormality was performed on resting-state fMRI data in 48 subjects: 24 controls, 13 patients with left TLE, and 11 patients with right TLE. Various network parameters were analyzed including betweenness centrality (BC), clustering coefficient (CC), path length (PL), small-world index (SWI), global efficiency (GE), connectivity strength (CS), and connectivity diversity (CD). These were compared for patients with TLE as a group, compared to controls, and for patients with left and right TLE separately. The association of changes in network parameters with epilepsy duration was also evaluated. We found that CC, CS, and CD decreased in subjects with TLE compared to control subjects. Analyzed according to epilepsy duration, patients with TLE showed a progressive reduction in CD. In conclusion, we found that several network parameters decreased in patients with TLE compared to controls, which suggested reduced connectivity in TLE. Reduction in CD associated with epilepsy duration suggests a homogenization of connections over time in TLE, indicating a reduction of the normal repertoire of stronger and weaker connections to other brain regions. PMID:25873437
Reduced heart rate variability during sleep in long-duration spaceflight.
Xu, D; Shoemaker, J K; Blaber, A P; Arbeille, P; Fraser, K; Hughson, R L
Limited data are available to describe the regulation of heart rate (HR) during sleep in spaceflight. Sleep provides a stable supine baseline during preflight Earth recordings for comparison of heart rate variability (HRV) over a wide range of frequencies using both linear, complexity, and fractal indicators. The current study investigated the effect of long-duration spaceflight on HR and HRV during sleep in seven astronauts aboard the International Space Station up to 6 mo. Measurements included electrocardiographic waveforms from Holter monitors and simultaneous movement records from accelerometers before, during, and after the flights. HR was unchanged inflight and elevated postflight [59.6 ▒ 8.9 beats per minute (bpm) compared with preflight 53.3 ▒ 7.3 bpm; P < 0.01]. Compared with preflight data, HRV indicators from both time domain and power spectral analysis methods were diminished inflight from ultralow to high frequencies and partially recovered to preflight levels after landing. During inflight and at postflight, complexity and fractal properties of HR were not different from preflight properties. Slow fluctuations (<0.04 Hz) in HR presented moderate correlations with movements during sleep, partially accounting for the reduction in HRV. In summary, substantial reduction in HRV was observed with linear, but not with complexity and fractal, methods of analysis. These results suggest that periodic elements that influence regulation of HR through reflex mechanisms are altered during sleep in spaceflight but that underlying system complexity and fractal dynamics were not altered. PMID:23637139
How a clock can change your pain? The illusion of duration and pain perception
Florence B. Pomares; Christelle CreacÆh; Isabelle Faillenot; Philippe Convers; Roland Peyron
The intensity of experimental pain is known to be dependent on stimulation duration. However, it remains unknown whether this effect arises largely from the actual stimulus duration or is substantially influenced by the subjectÆs perception of the stimulus duration. In the present study, we questioned this issue by misleading the perception of the duration of pain in a population of
Altered resting-state EEG source functional connectivity in schizophrenia: the effect of illness duration
Di Lorenzo, Giorgio; Daverio, Andrea; Ferrentino, Fabiola; Santarnecchi, Emiliano; Ciabattini, Fabio; Monaco, Leonardo; Lisi, Giulia; Barone, Ylenia; Di Lorenzo, Cherubino; Niolu, Cinzia; Seri, Stefano; Siracusano, Alberto
Despite the increasing body of evidence supporting the hypothesis of schizophrenia as a disconnection syndrome, studies of resting-state EEG Source Functional Connectivity (EEG-SFC) in people affected by schizophrenia are sparse. The aim of the present study was to investigate resting-state EEG-SFC in 77 stable, medicated patients with schizophrenia (SCZ) compared to 78 healthy volunteers (HV). In order to study the effect of illness duration, SCZ were divided in those with a short duration of disease (SDD; n = 25) and those with a long duration of disease (LDD; n = 52). Resting-state EEG recordings in eyes closed condition were analyzed and lagged phase synchronization (LPS) indices were calculated for each ROI pair in the source-space EEG data. In delta and theta bands, SCZ had greater EEG-SFC than HV; a higher theta band connectivity in frontal regions was observed in LDD compared with SDD. In the alpha band, SCZ showed lower frontal EEG-SFC compared with HV whereas no differences were found between LDD and SDD. In the beta1 band, SCZ had greater EEG-SFC compared with HVs and in the beta2 band, LDD presented lower frontal and parieto-temporal EEG-SFC compared with HV. In the gamma band, SDD had greater connectivity values compared with LDD and HV. This study suggests that resting state brain network connectivity is abnormally organized in schizophrenia, with different patterns for the different EEG frequency components and that EEG can be a powerful tool to further elucidate the complexity of such disordered connectivity. PMID:25999835
The signal of aerosol-induced changes in sunshine duration records: A review of the evidence
NASA Astrophysics Data System (ADS)
Sanchez-Romero, A.; Sanchez-Lorenzo, A.; Calb¾, J.; Gonzßlez, J. A.; Azorin-Molina, C.
Aerosols play a significant yet complex and central role in the Earth's radiation budget, and knowledge of long-term changes in the atmospheric turbidity induced by aerosols is therefore fundamental for a better understanding of climate change. However, there is little available information on changes in aerosol concentration in the atmosphere, especially prior to the 1980s. The present paper reviews publications reporting the suitability of sunshine duration records with regard to detecting changes in atmospheric aerosols. Some of the studies reviewed propose methods for estimating aerosol-related magnitudes, such as turbidity, from sunshine deficit at approximately sunrise and sunset, when the impact of aerosols on the solar beam is more easily observed. In addition, there is abundant evidence that one cause of the decadal changes observed in sunshine duration records involves variations in atmospheric aerosol loading. Possible directions for future research are also suggested: in particular, detailed studies of the burn (not only its length but also its width) registered by means of Campbell-Stokes sunshine recorders may provide a way of creating time series of atmospheric aerosol loading metrics dating back to over 120 years from the present.
Habitability and Performance Issues for Long Duration Space Flights
NASA Technical Reports Server (NTRS)
Whitmore, Mihriban; McQuilkin, Meredith L.; Woolford, Barbara J.
Advancing technology, coupled with the desire to explore space has resulted in increasingly longer manned space missions. Although the Long Duration Space Flights (LDSF) have provided a considerable amount of scientific research on human ability to function in extreme environments, findings indicate long duration missions take a toll on the individual, both physiologically and psychologically. These physiological and psychological issues manifest themselves in performance decrements; and could lead to serious errors endangering the mission, spacecraft and crew. The purpose of this paper is to document existing knowledge of the effects of LDSF on performance, habitability, and workload and to identify and assess potential tools designed to address these decrements as well as propose an implementation plan to address the habitability, performance and workload issues.
Rhythm measures and dimensions of durational variation in speech.
Loukina, Anastassia; Kochanski, Greg; Rosner, Burton; Keane, Elinor; Shih, Chilin
Patterns of durational variation were examined by applying 15 previously published rhythm measures to a large corpus of speech from five languages. In order to achieve consistent segmentation across all languages, an automatic speech recognition system was developed to divide the waveforms into consonantal and vocalic regions. The resulting duration measurements rest strictly on acoustic criteria. Machine classification showed that rhythm measures could separate languages at rates above chance. Within-language variability in rhythm measures, however, was large and comparable to that between languages. Therefore, different languages could not be identified reliably from single paragraphs. In experiments separating pairs of languages, a rhythm measure that was relatively successful at separating one pair often performed very poorly on another pair: there was no broadly successful rhythm measure. Separation of all five languages at once required a combination of three rhythm measures. Many triplets were about equally effective, but the confusion patterns between languages varied with the choice of rhythm measures. PMID:21568427
Test flights of the NASA ultra-long duration balloon
NASA Astrophysics Data System (ADS)
Cathey, H. M.
The National Aeronautics and Space Administration (NASA) Ultra-Long Duration Balloon development project is attempting to extend the potential flight durations for large scientific balloon payloads. The culmination of each of the development steps has been the fabrication and test flight of progressively larger balloons. This new super-pressure balloon is a pumpkin balloon design. This paper concentrates on the super-pressure balloon development test flights that have been, and are currently being planned by the NASA Balloon Program Office at Goddard Space Flight Center's Wallops Flight Facility. Descriptions of two test flights from early 2001 are presented along with lessons learned. Results are also presented of a July 2002 test flight of a full-scale 610,500 m 3 balloon with a 2800 kg suspended load that incorporated the lessons learned.
Short-duration Lensing Events. II. Expectations and Protocols
NASA Astrophysics Data System (ADS)
Di Stefano, Rosanne
Ongoing microlensing observations by OGLE and MOA regularly identify lensing events with Einstein diameter crossing time, ? E , of 16 or fewer days. Events with estimated values of ? E of one to two days have been detected. Short-duration events tend to be generated by low-mass lenses or by lenses with high transverse velocities. We compute the expected rates, demonstrate the expected ranges of parameters for lenses of different mass, and develop a protocol for observing and modeling short-duration events. Relatively minor additions to the procedures presently used will increase the rate of planet discovery, and also discover or place limits on the population of high-speed dim stars and stellar remnants in the vicinity of the Sun.
Pauses and durations exhibit a serial position effect.
Haberlandt, Karl; Lawrence, Holly; Krohn, Talia; Bower, Katherine; Thomas, J Graham
This article reports evidence of two kinds of serial position effects in immediate serial recall: One involves interresponse pauses, and the other response durations. In forward and backward recall, responding was faster at initial and final positions than at center positions, exhibitinga bow-shaped function relative to serial position. These data were obtained in a spoken recall study in which ungrouped lists of four to six words and postcuing of recall direction were used. The pause pattern is consistent with several models of serial memory, including a distinctiveness model (Brown, Neath, & Chater, 2002) and a version of the ACT-R model augmented with a spontaneous grouping strategy (Maybery, Parmentier, & Jones, 2002). The duration pattern suggests that response articulation depends on the processing context, rather than being modular. PMID:15945208
Space mechanisms needs for future NASA long duration space missions
NASA Technical Reports Server (NTRS)
Fusaro, Robert L.
Future NASA long duration missions will require high performance, reliable, long lived mechanical moving systems. In order to develop these systems, high technology components, such as bearings, gears, seals, lubricants, etc., will need to be utilized. There has been concern in the NASA community that the current technology level in these mechanical component/tribology areas may not be adequate to meet the goals of long duration NASA mission such as Space Exploration Initiative (SEI). To resolve this concern, NASA-Lewis sent a questionnaire to government and industry workers (who have been involved in space mechanism research, design, and implementation) to ask their opinion if the current space mechanisms technology (mechanical components/tribology) is adequate to meet future NASA Mission needs and goals. In addition, a working group consisting of members from each NASA Center, DoD, and DOE was established to study the technology status. The results of the survey and conclusions of the working group are summarized.
Shorter spontaneous fixation durations in infants with later emerging autism
Wass, Sam V.; Jones, Emily J. H.; Gliga, Teodora; Smith, Tim J.; Charman, Tony; Johnson, Mark H.; Baron-Cohen, Simon; Bedford, Rachael; Bolton, Patrick; Chandler, Susie; Davies, Kim; Fernandes, Janice; Garwood, Holly; Hudry, Kristelle; Maris, Helen; Pasco, Greg; Pickles, Andrew; Ribiero, Helena; Tucker, Leslie; Volein, Agnes
Little is known about how spontaneous attentional deployment differs on a millisecond-level scale in the early development of autism spectrum disorders (ASD). We measured fine-grained eye movement patterns in 6-to 9-month-old infants at high or low familial risk (HR/LR) of ASD while they viewed static images. We observed shorter fixation durations (i.e. the time interval between saccades) in HR than LR infants. Preliminary analyses indicate that these results were replicated in a second cohort of infants. Fixation durations were shortest in those infants who went on to receive an ASD diagnosis at 36 months. While these findings demonstrate early-developing atypicality in fine-grained measures of attentional deployment early in the etiology of ASD, the specificity of these effects to ASD remains to be determined. PMID:25655672
Average outage duration of multihop communication systems with regenerative relays
Lin Yang; Mazen O. Hasna; Mohamed-slim Alouini
Closed-form expressions for the average outage duration (AOD) of multihop regenerative communication systems over generalized fading channels are presented. Both noise-limited and interference-limited systems are studied. To show the usefulness of the presented expressions, some specific fading scenarios are considered. In addition, some numerical examples of interest comparing direct versus relayed transmission and studying the effect of increasing the number
Combination of Rimonabant and Donepezil Prolongs Spatial Memory Duration
Laura E Wise; Philip A Iredale; Rene J Stokes; Aron H Lichtman
The observations that the cannabinoid1(CB1) receptor antagonist\\/inverse agonist, rimonabant, and the selective noncompetitive inhibitor of acetylcholinesterase (AChE), donepezil, improve performance in a variety of animal memory models, suggest that these neurochemical systems play integral roles in cognition. The present study tested whether each of these agents administered alone or in combination will prolong the duration of spatial memory. Rats were
Progress toward a microsecond duration, repetitively pulsed, intense- ion beam
Davis, H.A.; Olson, J.C.; Reass, W.A. [Los Alamos National Lab., NM (United States); Coates, D.M.; Hunt, J.W.; Schleinitz, H.M. [Du Pont de Nemours (E.I.) and Co., Wilmington, DE (United States). Central Research and Development Dept.; Lovberg, R.H. [California Univ., San Diego, La Jolla, CA (United States); Greenly, J.B. [Cornell Univ., Ithaca, NY (United States). Lab. of Plasma Studies
A number of intense ion beams applications are emerging requiring repetitive high-average-power beams. These applications include ablative deposition of thin films, rapid melt and resolidification for surface property enhancement, advanced diagnostic neutral beams for the next generation of Tokamaks, and intense pulsed-neutron sources. We are developing a 200-250 keV, 15 kA, 1 {mu}s duration, 1-30 Hz intense ion beam accelerator to address these applications.
Plasma Cytokine Levels During Long-Duration Spaceflight
NASA Technical Reports Server (NTRS)
Crucian, Brian E.; Zwart, Sara R.; Quiriarte, Heather A.; Smith, Scott M.; Sams, Clarence F.
Reduced T cell, granulocyte, NK and monocyte function have all been reported following both long and short duration spaceflight, however these data indicate crews are generally not experiencing inflammatory or adaptive immune activation during spaceflight. There appear to be varied individual crew responses, and specific relationships between cytokines and markers of iron status and muscle turnover that warrant further evaluation. Increases in growth factors and chemokines may indicate other types of adaptation occurring during spaceflight, such as attempts to overcome diminished immunocyte function.
Test flights of the NASA ultra long duration balloon
NASA Astrophysics Data System (ADS)
Cathey, H.
The NASA Ultra Long Duration Balloon development project is attempting to extend the potential flight durations for large scientific balloon payloads. The culmination of each of the development steps has been the fabrication and test flight of progressively larger balloons. This new super-pressure balloon is a pumpkin balloon design. This paper concentrates on the super-pressure balloon development test flights that have been, and are currently being planned by the National Aeronautics and Space Administration (NASA) Balloon Program Office at Goddard Space Flight Center's Wallops Flight Facility. Two Ultra Long Duration balloon test flights took place from Australia in early 2001. The results from these flights, as well as the challenges presented, will be discussed. With these lessons learned and incorporating both material and design improvements, a test flight of a full-scale 610,500m3 balloon with a 2,800 kg suspended load will be completed in Spring of 2002 from Ft. Sumner, New Mexico. This balloon, the largest single celled super- pressure balloon ever flown, has been sized to satisfy the requirements for the planned ULDB CREAM mission in late 2003. A description of the balloon design, including the modifications made as a result of the lessons learned from the two Australia flights, will be presented. The results, highlighting balloon performance, from the Spring 2002 test flight will be presented. This will include information related to the balloon preparation, flight operations, and flight performance. A review of the radiative environmental influences on the balloon related to this flight will be presented. A second test flight of a full-scale Ultra Long Duration Balloon is scheduled for December of 2002. This flight is expected to be one orbit or approximately 15 days. The plans for this Southern Hemisphere, Australia launched, global flight will also be presented.
Duration Test Report for the Viryd CS8 Wind Turbine
Roadman, J.; Murphy, M.; van Dam, J.
This report summarizes the results of a duration noise test that the National Renewable Energy Laboratory (NREL) conducted on the Viryd CS8 wind turbine. This test was conducted in accordance with Clause 9.4 of the International Electrotechnical Commission's (IEC) standard, Wind turbines - Part 2: Design requirements for small wind turbines, IEC 61400-2 Ed. 2.0:2006-03. NREL researchers evaluated the turbine based on structural integrity and material degradation, quality of environmental protection, and dynamic behavior.
Cultural and Gender Issues in Long-Duration Flights
NASA Technical Reports Server (NTRS)
Session TA5 includes short reports concerning: (1) Psychological Issues During Long-Duration International Space Missions; (2) Psychosocial Issues in Crew Selection: Finding the Right Mix of the Right Stuff; (3) Culture, Gender and Mission Accomplishment: Operational Experience; (4) Interpersonal Tension in Multicultural Crews; (5) Personality and Coping in Extreme Environments; and (6) Application of Expedition and Polar Work Group Findings for Enhancing Performance in Space.
Radiation-shielding requirements on long-duration space missions
J. R. Letaw; S. Clearwater
An analysis of radiation shielding requirements on long duration space missions is presented. The report finds the principal radiation hazards to be galactic cosmic radiation (cosmic rays) and radiation from solar flares. Galactic cosmic radiation is a continuous source of radiation delivering a dose equivalent to the blood-forming organs varying from 20 REM\\/year to 50 REM\\/year over the 11-year solar
Inductively stabilized, long pulse duration transverse discharge apparatus
Sze, Robert C. (Santa Fe, NM)
An inductively stabilized, long pulse duration transverse discharge apparatus. The use of a segmented electrode where each segment is attached to an inductive element permits high energy, high efficiency, long-pulsed laser outputs to be obtained. The present apparatus has been demonstrated with rare-gas halide lasing media. Orders of magnitude increase in pulse repetition frequency are obtained in lasing devices that do not utilize gas flow.
Racial disparities in short sleep duration by occupation and industry.
Jackson, Chandra L; Redline, Susan; Kawachi, Ichiro; Williams, Michelle A; Hu, Frank B
Short sleep duration, which is associated with increased morbidity and mortality, has been shown to vary by occupation and industry, but few studies have investigated differences between black and white populations. By using data from a nationally representative sample of US adult short sleepers (n = 41,088) in the National Health Interview Survey in 2004-2011, we estimated prevalence ratios for short sleep duration in blacks compared with whites for each of 8 industry categories by using adjusted Poisson regression models with robust variance. Participants' mean age was 47 years; 50% were women and 13% were black. Blacks were more likely to report short sleep duration than whites (37% vs. 28%), and the black-white disparity was widest among those who held professional occupations. Adjusted short sleep duration was more prevalent in blacks than whites in the following industry categories: finance/information/real estate (prevalence ratio (PR) = 1.44, 95% confidence interval (CI): 1.30, 1.59); professional/administrative/management (PR = 1.30, 95% CI: 1.18, 1.44); educational services (PR = 1.39, 95% CI: 1.25, 1.54); public administration/arts/other services (PR = 1.30, 95% CI: 1.21, 1.41); health care/social assistance (PR = 1.23, 95% CI: 1.14, 1.32); and manufacturing/construction (PR = 1.14, 95% CI: 1.07, 1.20). Short sleep generally increased with increasing professional responsibility within a given industry among blacks but decreased with increasing professional roles among whites. Our results suggest the need for further investigation of racial/ethnic differences in the work-sleep relationship. PMID:24018914
Impact of the Baking Duration on Bread Staling Kinetics
Alain Le-Bail; Soumya Agrane; Delphine Queveau
This paper presents a study on the impact of the duration of the baking plateau on staling kinetics in the case of bread crumb\\u000a made of sourdough; it follows Le-Bail et al. Journal of Cereal Science 50:235¢240, (2009)a previous study proposed by Le-Bail et al. Journal of Cereal Science 50:235¢240, (2009) on the impact of heating rate during baking on
Adaptive Sensing and Transmission Durations for Cognitive Radios
Wessam Afifi; Ahmed Sultan; Mohammed Nafie
In a cognitive radio setting, secondary users opportunistically access the spectrum allocated to primary users. Finding the optimal sensing and transmission durations for the secondary users becomes crucial in order to maximize the secondary throughput while protecting the primary users from interference and service disruption. In this paper an adaptive sensing and transmission scheme for cognitive radios is proposed. We consider a channel allocated to a primary user which operates in an unslotted manner switching activity at random times. A secondary transmitter adapts its sensing and transmission durations according to its belief regarding the primary user state of activity. The objective is to maximize a secondary utility function. This function has a penalty term for collisions with primary transmission. It accounts for the reliability-throughput tradeoff by explicitly incorporating the impact of sensing duration on secondary throughput and primary activity detection reliability. It also accounts for throughput reduction that results from data overhead. Numerical simulations of the system performance demonstrate the effectiveness of adaptive sensing and transmission scheme over non-adaptive approach in increasing the secondary user utility.
[The optimal duration of anticoagulant treatment following pulmonary embolism].
Couturaud, F
The optimal course of oral anticoagulant therapy is determined according to the risk of recurrent venous thromboembolism after stopping therapy and the risk of anticoagulant-related bleeding. Clinical risk factors appear to be important in predicting the risk of recurrence whereas the influence of biochemical and morphological tests is uncertain. The risk of recurrent venous thromboembolism is low when the initial episode was provoked by a reversible major risk factor (surgery): 3 months of anticoagulation is sufficient. Conversely, the risk is high when venous thromboembolism was unprovoked or associated with persistent risk factor (cancer): 6 months or more prolonged anticoagulation is necessary. After this first estimation, the duration of anticoagulation may be modulated according to the presence or absence of certain additional risk factors (major thrombophilia, chronic pulmonary hypertension, massive pulmonary embolism): 6 months if pulmonary embolism was provoked and 12 to 24 months if pulmonary embolism was unprovoked. If the risk of anticoagulant-related bleeding is high, the duration of anticoagulation should be shortened (3 months if pulmonary embolism was provoked and 3 to 6 months if it was unprovoked). Lastly, if pulmonary embolism occurred in association with cancer, anticoagulation should be conducted for 6 months or more if the cancer is active or treatment is on going. Despite an increasing knowledge of the risk factors for recurrent venous thromboembolism, a number of issues remain unresolved. Randomised trials comparing different durations of anticoagulation are needed. PMID:22152935
Physiology, medicine, long-duration space flight and the NSBRI.
McPhee, J C; White, R J
The hazards of long-duration space flight are real and unacceptable. In order for humans to participate effectively in long-duration orbital missions or continue the exploration of space, we must first secure the health of the astronaut and the success of such missions by assessing in detail the biomedical risks of space flight and developing countermeasures to these hazards. Acquiring the understanding necessary for building a sound foundation for countermeasure development requires an integrated approach to research in physiology and medicine and a level of cooperative action uncommon in the biomedical sciences. The research program of the National Space Biomedical Research Institute (NSBRI) was designed to accomplish just such an integrated research goal, ameliorating or eliminating the biomedical risks of long-duration space flight and enabling safe and productive exploration of space. The fruits of these labors are not limited to the space program. We can also use the gained understanding of the effects and mechanisms of the physiological changes engendered in space and the applied preventive and rehabilitative methods developed to combat these changes to the benefit of those on Earth who are facing similar physiological and psychological difficulties. This paper will discuss the innovative approach the NSBRI has taken to integrated research management and will present some of the successes of this approach. PMID:14649253
Physiology, medicine, long-duration space flight and the NSBRI
NASA Astrophysics Data System (ADS)
McPhee, J. C.; White, R. J.
The hazards of long-duration space flight are real and unacceptable. In order for humans to participate effectively in long-duration orbital missions or continue the exploration of space, we must first secure the health of the astronaut and the success of such missions by assessing in detail the biomedical risks of space flight and developing countermeasures to these hazards. Acquiring the understanding necessary for building a sound foundation for countermeasure development requires an integrated approach to research in physiology and medicine and a level of cooperative action uncommon in the biomedical sciences. The research program of the National Space Biomedical Research Institute (NSBRI) was designed to accomplish just such an integrated research goal, ameliorating or eliminating the biomedical risks of long-duration space flight and enabling safe and productive exploration of space. The fruits of these labors are not limited to the space program. We can also use the gained understanding of the effects and mechanisms of the physiological changes engendered in space and the applied preventive and rehabilitative methods developed to combat these changes to the benefit of those on Earth who are facing similar physiological and psychological difficulties. This paper will discuss the innovative approach the NSBRI has taken to integrated research management and will present some of the successes of this approach.
Physiology, Medicine, Long-Duration Space Flight and the NSBRI
NASA Astrophysics Data System (ADS)
White, R. J.; Sutton, J. P.; McPhee, J. C.
The hazards of long-duration space flight are real and unacceptable. In order for humans to participate effectively in long-duration orbital missions or continue the exploration of space, we must first secure the health of the astronaut and the success of such missions by assessing in detail the biomedical risks of space flight and developing countermeasures to these hazards. Acquiring the understanding necessary for building a sound foundation for countermeasure development requires an integrated approach to research in physiology and medicine and a level of cooperative action uncommon in the biomedical sciences. The research program of the National Space Biomedical Research Institute (NSBRI) was designed to accomplish just such an integrated research goal, ameliorating or eliminating the biomedical risks of long-duration space flight and enabling safe and productive exploration of space. The fruits of these labors are not limited to the space program. We can also use the gained understanding of the effects and mechanisms of the physiological changes engendered in space and the applied preventive and rehabilitative methods developed to combat these changes to the benefit of those on Earth who are facing similar physiological and psychological difficulties. This paper will discuss the innovative approach the NSBRI has taken to integrated research management and will present some of the successes of this approach.
Ecohydrological modelling of flow duration curve in Mediterranean river basins
NASA Astrophysics Data System (ADS)
Pumo, Dario; Noto, Leonardo Valerio; Viola, Francesco
Flow duration curve provides an important synthesis of the relevant hydrological processes occurring at the basin scale, and, although it is typically obtained from field observations, different theoretical approaches finalized to its indirect reconstruction have been developed in recent years. In this study a recent ecohydrological model for the probabilistic characterization of base flows is tested through its application to a study catchment located in southern Italy, where long historical series of daily streamflow are available. The model, coupling soil moisture balance with a simplified scheme of the hydrological response of the basin, provides the daily flow duration curve. The original model is here modified in order to account for rainfall reduction due to canopy interception and stress its potential applicability to most of the ephemeral Mediterranean basins, where measurements of air temperature and rainfall often represent the only meteorological data available. The model shows a high sensitivity to two parameters related to the transport and evapotranspiration processes. Two different operational approaches for the identification of such parameters are explored and compared: by the first approach, these parameters are considered as time invariant quantities, while, in the second approach, empirical relationships between such parameters and the underlying climatic forcings are first derived and then adopted in the parameters calibration procedure. The model ability in reproducing the empirical flow duration curves and the model sensitivity to climate forcings, here referred as elasticity of the model, are investigated and it is shown how the adoption of the second approach leads to a general improvement of the model elasticity.
Extended duration local anesthetic agent in a rat paw model.
Ickowicz, D E; Golovanevski, L; Domb, A J; Weiniger, C F
Encapsulated local anesthetics extend postoperative analgesic effect following site-directed nerve injection; potentially reducing postoperative complications. Our study aim was to investigate efficacy of our improved extended duration formulation - 15% bupivacaine in poly(DL-lactic acid co castor oil) 3:7 synthesized by ring opening polymerization. In vitro, around 70% of bupivacaine was released from the p(DLLA-CO) 3:7 after 10 days. A single injection of the optimal formulation of 15% bupivacaine-polymer or plain (0.5%) bupivacaine (control), was injected via a 22G needle beside the sciatic nerve of Sprague-Dawley rats under anesthesia; followed (in some animals) by a 1cm longitudinal incision through the skin and fascia of the paw area. Behavioral tests for sensory and motor block assessment were done using Hargreave's hot plate score, von Frey filaments and rearing count. The 15% bupivacaine formulation significantly prolonged sensory block duration up to at least 48 h. Following surgery, motor block was observed for 48 h following administration of bupivacaine-polymer formulation and rearing was reduced (returning to baseline after 48 h). No significant differences in mechanical nociceptive response were observed. The optimized bupivacaine-polymer formulation prolonged duration of local anesthesia effect in our animal model up to at least 48 h. PMID:24726301
... Ephelides (freckles) LAMB syndrome ¢ Lentigines, Atrial Myxoma, and Blue nevi What causes Carney complex? Carney complex is ... melanotic schwannoma, meaning tumors that grow on nerves Blue nevi, which are blue-black moles Osteochondromyxoma (bone ...
The duration of lone parenthood in Great Britain.
Ermisch, J F; Wright, R E
Proportional hazards model analyses were conducted to examine the duration of lone parenthood among British women in 1980. Marital, demographic, and employment histories for 5320 women were collected from the Women and Employment Survey. A distinction is made between never married and previously married lone parents. Variables that affect the remarriage rate are occupation in last job before 1st birth, number of children at time of marital dissolution, age of youngest child at marital dissolution, period of marital dissolution, age at time of marital dissolution, duration of 1st marriage, work experience at end of 1st marriage, employment some time in the 12 months prior to marital dissolution, and highest educational qualifications. Characteristics that change over time and variables that pertain to the economic environment are also included. The statistical approach was to 1st build a general model with all the detailed variables, current employment status variables, and the macro environmental variables. In this model only women's real wages and real welfare benefits had statistical significance. Further refinements in the model were then made. The log of real welfare benefits as the only macro variable included in the specification revealed a positive and statistically significant relationship to the remarriage rate (x2=1.16). When the log of real wage is included, it has a negative effect which is statistically insignificant (x2=1.25). When both are included in a model, both are significant with opposite signs. The interpretation is that when women earn more in employment, they are less likely to remarry and remain lone parents longer. The duration of lone parenthood has the strongest association with the age of the woman. The type of job she had before becoming a mother and whether she had a job in the year prior to the dissolution of her marriage are strongly associated with the duration of lone parenthood for those previously married mothers. Results also suggest that lone mothers with poorer economic conditions remain lone parents longer. After the Divorce Reform Act, the number of people reentering the marriage market increased and previously married mother's duration of lone parenthood shortened. For previously married mothers, higher welfare payments directly or indirectly prolong the length of lone parenthood. PMID:12158963
Wolfgang Fikentscher
This paper is divided into four parts. The first section (I.) consists of definitions which center on the concept of complexity. As a minimum, the terms, system, complexity, and adaptation as used in this paper need an explanation. The second section (II.) is a sketch of cultural complexity in the real world. I will use Pueblo tribal laws and other
Association between screen viewing duration and sleep duration, sleep quality, and excessive daytime sleepiness among adolescents in Hong Kong.
Mak, Yim Wah; Wu, Cynthia Sau Ting; Hui, Donna Wing Shun; Lam, Siu Ping; Tse, Hei Yin; Yu, Wing Yan; Wong, Ho Ting
Screen viewing is considered to have adverse impacts on the sleep of adolescents. Although there has been a considerable amount of research on the association between screen viewing and sleep, most studies have focused on specific types of screen viewing devices such as televisions and computers. The present study investigated the duration with which currently prevalent screen viewing devices (including televisions, personal computers, mobile phones, and portable video devices) are viewed in relation to sleep duration, sleep quality, and daytime sleepiness among Hong Kong adolescents (N = 762). Television and computer viewing remain prevalent, but were not correlated with sleep variables. Mobile phone viewing was correlated with all sleep variables, while portable video device viewing was shown to be correlated only with daytime sleepiness. The results demonstrated a trend of increase in the prevalence and types of screen viewing and their effects on the sleep patterns of adolescents. PMID:25353062
Improved technique for picosecond pulse duration measurement based on second harmonic generation
NASA Astrophysics Data System (ADS)
Shelestov, D. A.; Karasik, V. E.; Koshelev, K. I.; Lazarev, V. A.; Pnev, A. B.
In present paper we demonstrated an improved technique for characterization of ultra-short pulse duration (PD) based on second harmonic generation (SHG). We utilized Yb- doped fiber laser with picosecond duration of pulses as implementation of proposed technique and for estimating the accuracy of pulse duration measurement. KTiOPO4 crystal was used for the purpose of second harmonic generation. We determined the duration of laser pulses by analysing the combination of signal intensities on input and output of SHG crystal. We observed experimentally error of pulse duration measurement less then 2%. We showed strong dependence between the average power of SHG and the duration of picosecond pulses.
Local field effect as a function of pulse duration
Novitsky, Denis V. [B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Nezavisimosti Avenue 68, 220072 Minsk (Belarus)
In this brief report we give semiclassical consideration to the role of pulse duration in the observation of local field effects in the regime of optical switching. We show that the main parameter governing local field influence is the ratio of peak Rabi frequency corresponding to medium inversion and Lorentz frequency of the medium. To obtain significant local field effect, this parameter should be near unity that is valid only for long enough pulses. We also discuss the role of relaxation and pulse shape in this process.
Flash duration effect in one-sided thermal imaging.
Sun, J. G.; Benz, J.; Energy Technology
Theoretical formulation is developed for one-sided thermal imaging that utilizes an infrared camera for temperature measurement and photographic flash lamps for radiant heating of the sample surface. This formulation accounts for the radiant intensity variation of flash lamps, which typically exhibit a short rise time but a long exponential-decay time (several milliseconds). During the flash, the infrared camera receives radiation from the emission of the sample surface as well as the reflection of the flash energy. Experimental results clearly show the flash-reflection effect and the temperature response of the sample surface under finite flash durations. Theoretical and experimental data are compared and discussed.
Foot Reaction Forces during Long Duration Space Flight
NASA Technical Reports Server (NTRS)
Gopalakrishnan, R.; Rice, A. J.; Genc, K. O.; Maender, C. C.; Kuklis, M. M.; Humphreys, B.; Cavanagh, P. R.
Musculoskeletal changes, particularly in the lower extremities, are an established consequence of long-duration space flight despite exercise countermeasures. It is widely believed that disuse and reduction in load bearing are key to these physiological changes, but no quantitative data characterizing the on-orbit movement environments currently exist. Here we present data from the Foot Experiment (E318) regarding astronaut activity on the ground and on-orbit during typical days from 4 International Space Station (ISS) crew members who flew during increments 6, 8, 11, and 12.
The establishment and duration of breastfeeding. Part 1: Hospital influences.
Vogel, A M; Mitchell, E A
Most New Zealand mothers initiate breastfeeding in hospital, but many continue for only a relatively short time. Focus group discussions with mothers and health care workers on their perceptions of important factors influencing the duration of breastfeeding indicated many negative initial hospital experiences. Specific concerns included overworked staff; lack of health care workers' skills, particularly in helping infants to latch on; inconsistent advice; noise and embarrassment in four bedded rooms; and the impact of changes in the provision of maternity services and funding. PMID:9618601
Laser duration and intensity limits in plasma backward Raman amplifiers
NASA Astrophysics Data System (ADS)
Malkin, V. M.; Toroker, Z.; Fisch, N. J.
The shortest duration and the largest non-focused intensity of laser pulses produced by means of backward Raman amplification (BRA) in plasmas are calculated. These limits occur in moderately undercritical plasmas and are imposed by combined effects of moderately small group velocity dispersion and relativistic electron nonlinearity of the amplified pulses. The efficient BRA range covered by this theory is broader than one known previously. This can be useful for BRA of x-ray pulses in regular or compressed solids and ultra-powerful optical pulses in the lowest density solids.
Are the Effects of Duration of Untreated Psychosis Socially Mediated?
Norman, Ross M G
Investigation of possible mechanisms by which longer duration of untreated psychosis (DUP) could influence treatment outcomes has focused primarily on evidence for neurotoxic effects. It is also possible that longer DUP has psychosocial effects, which could mediate its impact on outcomes. The evidence of relevance to such socially toxic effects is reviewed, with particular reference to the possible role of social support. There is no definite evidence for social support as a mediator of the influence of DUP, but further investigation of this issue is warranted. PMID:25565684
Quantiles Regression Approach to Identifying the Determinant of Breastfeeding Duration
NASA Astrophysics Data System (ADS)
Mahdiyah; Norsiah Mohamed, Wan; Ibrahim, Kamarulzaman
In this study, quantiles regression approach is applied to the data of Malaysian Family Life Survey (MFLS), to identify factors which are significantly related to the different conditional quantiles of the breastfeeding duration. It is known that the classical linear regression methods are based on minimizing residual sum of squared, but quantiles regression use a mechanism which are based on the conditional median function and the full range of other conditional quantile functions. Overall, it is found that the period of breastfeeding is significantly related to place of living, religion and total number of children in the family.
Introduction to duration concepts: application to bank managementĀ
Meyers, Alison J.
+125 5. 23 1 ~ 33 +100 +125 1 ' 61 0. 29 +100 +125 0. 35 0. 05 +150 0 16 +150 O. D2 +150 0. 01 100. 00 100. 00 100. 00 -31- ~Ad i B Assets Table B. l ? Initial Balance Sheet Liabilities Cash Reserves Business Loans Mortgage Loans... ? Analysis of Initial Balance Sheet Accounts Accounts 4 4 4 ~MA Ad Duration Cash Reserves Business Loans Nortgage Loans Total Assets O. OOX 13. 00X 13. 00X 0. 0 Years 2. 5 Years 30. 0 Years 0. 00 Years 1. 22 Years F 14 Years 4. 06 Years 1-Year...
Long-duration orbital effects on optical coating materials.
Herzig, H; Toft, A R; Fleetwood, C M
We flew specimens of eight different optical coating materials in low earth orbit as part of the Long Duration Exposure Facility manifest to determine their ability to withstand exposure to the residual atomic O and other environmental effects at those altitudes. We included samples of Al, Au, Ir, Os, Pt, Al + MgF(2), Al + SiO(x), and chemical-vapor-deposited SiC, representing reflective optical applications from the vacuum ultraviolet through the visible portions of the spectrum. We found that the majority of the materials suffered sufficient reflectance degradation to warrant careful consideration in the design of future space-flight instrumentation. PMID:20820314
Localization of sound in rooms, III: Onset and duration effects.
Rakerd, B; Hartmann, W M
The steady-state sound field of a sine tone does not provide useful localization information in a room. Nevertheless, listeners can localize a sine tone in a room if it has an onset transient which allows the precedence effect to operate. In the present study, we made a quantitative assessment of onsets and the precedence effect by systematically varying onset duration from 0 s (impulsive), where the precedence effect is maximal, to 5 s, where there is no precedence effect at all. We also assessed listeners' sensitivity to the steady-state sound field under impulsive conditions by varying the total duration of tone pulses. Our experiments were conducted in a room with a single acoustical reflection having various directions and delays, and in an anechoic room. The results for tones of various frequencies (500 and 2000 Hz) and sound-pressure levels (65 and 40 dBA) indicate the following: Localization in rooms is facilitated by onsets even if the onsets are as long as 100 ms. The facilitation depends upon the peak intensity of the tone, as well as the onset duration, suggesting that onset rate is critical for the precedence effect; our results are most consistent with rate expressed as an increase in sound pressure per unit time. The facilitation also depends upon the reflection delay time for a room; gradual onsets take on much more importance for the precedence effect in rooms with long delays. As onsets begin to lose their effectiveness listeners become increasingly "misdirected" by invalid cues in the steady-state sound field. The pattern of misdirection suggests a perceptual averaging of cues over an interval more than an order of magnitude longer than previous estimates of the summation window for the precedence effect. The pattern of misdirection varies with the frequency of a tone, due to frequency-dependent interference effects in a room, but it is independent of signal level. Localization of an impulsive sine tone in rooms is very insensitive to the pulse duration; this suggests that binaural inhibition models of the precedence effect must be supplemented by an evaluative component that we term the "plausibility hypothesis." PMID:3794076
Plasmid CpG Depletion Improves Degree and Duration of Tumor Gene Expression After Intravenous Administration of Polyplexes
de Wolf, Holger K.; Johansson, Nina; Thong, Anh-Thy; Snel, Cor J.; Mastrobattista, Enrico; Hennink, Wim E.
Purpose Tumor gene expression after the intravenous (i.v.) administration of current polymer-based gene delivery systems is generally low and short-lived. Immune stimulatory CpG dinucleotides, present within the plasmid DNA of the polyplexes are likely to contribute to this. The effect of CpG replacement on the levels of transgene expression was studied, after the i.v. administration of polyethylenimine (PEI) polyplexes. Methods Tumor transfection and immune stimulation of PEI polyplexes containing plasmid DNA encoding for luciferase and rich in CpG motifs was monitored and compared to polyplexes containing the same gene but devoid of CpG motifs. Lipoplexes based on 1,2-dioleyl-3-trimethylammonium-propane/dioleoylphosphatidylethanolamine liposomes were included as a control. Results The replacement of CpGrich DNA by CpGfree DNA did neither affect the physical properties of the DNA complexes nor did it affect their in vitro transfection activity or cytotoxicity. The immune stimulation (interleukin-12) after i.v. administration of the PEI DNA complexes was low and unaffected by the presence of CpG motifs. The absence of CpG motifs within the different DNA complexes improved the degree and the duration of organ and tumor gene expression. Conclusion The depletion of CpG dinucleotides within the plasmid DNA of polyplexes enhances the degree and duration of in vivo transgene expression. PMID:18317886
15 CFR 918.4 - Duration of Sea Grant College designation.
Code of Federal Regulations, 2012 CFR
...2012-01-01 2012-01-01 false Duration of Sea Grant College designation. 918.4 Section...DEPARTMENT OF COMMERCE GENERAL REGULATIONS SEA GRANTS ¦ 918.4 Duration of Sea Grant College designation. Designation...
15 CFR 918.4 - Duration of Sea Grant College designation.
Code of Federal Regulations, 2013 CFR
...2013-01-01 2013-01-01 false Duration of Sea Grant College designation. 918.4 Section...DEPARTMENT OF COMMERCE GENERAL REGULATIONS SEA GRANTS ¦ 918.4 Duration of Sea Grant College designation. Designation...
15 CFR 918.4 - Duration of Sea Grant College designation.
Code of Federal Regulations, 2014 CFR
...2014-01-01 2014-01-01 false Duration of Sea Grant College designation. 918.4 Section...DEPARTMENT OF COMMERCE GENERAL REGULATIONS SEA GRANTS ¦ 918.4 Duration of Sea Grant College designation. Designation...
15 CFR 918.6 - Duration of Sea Grant Regional Consortium designation.
Code of Federal Regulations, 2014 CFR
...2014-01-01 2014-01-01 false Duration of Sea Grant Regional Consortium designation. 918...DEPARTMENT OF COMMERCE GENERAL REGULATIONS SEA GRANTS ¦ 918.6 Duration of Sea Grant Regional Consortium designation....
15 CFR 918.6 - Duration of Sea Grant Regional Consortium designation.
Code of Federal Regulations, 2012 CFR
...2012-01-01 2012-01-01 false Duration of Sea Grant Regional Consortium designation. 918...DEPARTMENT OF COMMERCE GENERAL REGULATIONS SEA GRANTS ¦ 918.6 Duration of Sea Grant Regional Consortium designation....
15 CFR 918.6 - Duration of Sea Grant Regional Consortium designation.
Code of Federal Regulations, 2013 CFR
...2013-01-01 2013-01-01 false Duration of Sea Grant Regional Consortium designation. 918...DEPARTMENT OF COMMERCE GENERAL REGULATIONS SEA GRANTS ¦ 918.6 Duration of Sea Grant Regional Consortium designation....
The Effect of Exposure Duration on Stereopsis and Its Dependency on Spatial Frequency
NASA Astrophysics Data System (ADS)
Lee, Seungbae; Shioiri, Satoshi; Yaguchi, Hirohisa
To investigate the effect of exposure duration on stereopsis and its spatial frequency dependency, we measured disparity threshold for the depth discrimination varying stimulus exposure duration between 0.05 and 2 s for three spatial frequencies (0.23, 0.94 and 3.75 c/deg). The results showed that disparity threshold decreased with increase in exposure duration up to a certain duration, beyond which it was approximately constant (the duration is called critical duration). The critical duration was about 150 ms for gratings with low and middle spatial frequencies (0.23 and 0.94 c/deg) while the duration was about 750 ms for gratings with high spatial frequency (3.75 c/deg). This suggests that temporal integration property varies dependently on stimulus spatial frequency. We also attempted to relate the spatial frequency dependency of the temporal integration property to the differences in temporal frequency tuning to different spatial frequency stimuli.
Shafran, Izhak
DISCRIMINATIVELY ESTIMATED JOINT ACOUSTIC, DURATION, AND LANGUAGE MODEL FOR SPEECH RECOGNITION model for speech recognition that integrates acoustic, duration and language components role in Arabic task. Index Terms-- discriminative modeling, language mod- eling, acoustic modeling
38 CFR 21.6072 - Extending the duration of a vocational training program.
Code of Federal Regulations, 2010 CFR
...Extending the duration of a vocational training program. 21.6072 Section 21.6072...EDUCATION Temporary Program of Vocational Training for Certain New Pension Recipients Duration of Training ¦ 21.6072 Extending the...
13 CFR 107.830 - Minimum duration/term of financing.
Code of Federal Regulations, 2011 CFR
...Terms and Conditions of Financing ¦ 107.830 Minimum duration/term of financing. (a) General rule...duration/term of all your Financings must be for a minimum period...mandatory redemption of Equity Securities. If you...
13 CFR 107.830 - Minimum duration/term of financing.
Code of Federal Regulations, 2010 CFR
...Terms and Conditions of Financing ¦ 107.830 Minimum duration/term of financing. (a) General rule...duration/term of all your Financings must be for a minimum period...mandatory redemption of Equity Securities. If you...
13 CFR 107.830 - Minimum duration/term of financing.
Code of Federal Regulations, 2014 CFR
...Terms and Conditions of Financing ¦ 107.830 Minimum duration/term of financing. (a) General rule...duration/term of all your Financings must be for a minimum period...mandatory redemption of Equity Securities. If you...
13 CFR 107.830 - Minimum duration/term of financing.
Code of Federal Regulations, 2012 CFR
...Terms and Conditions of Financing ¦ 107.830 Minimum duration/term of financing. (a) General rule...duration/term of all your Financings must be for a minimum period...mandatory redemption of Equity Securities. If you...
13 CFR 107.830 - Minimum duration/term of financing.
Code of Federal Regulations, 2013 CFR
...Terms and Conditions of Financing ¦ 107.830 Minimum duration/term of financing. (a) General rule...duration/term of all your Financings must be for a minimum period...mandatory redemption of Equity Securities. If you...
Model of medical supply demand and astronaut health for long-duration human space flight
Assad, Albert
The medical care of space crews is the primary limiting factor in the achievement of long-duration space missions. (Nicogossian 2003) The goal of this thesis was to develop a model of long-duration human space flight ...
46 CFR 31.40-40 - Duration of Convention certificates-T/ALL.
Code of Federal Regulations, 2010 CFR
...2010-10-01 false Duration of Convention certificates-T/ALL. 31.40-40... Certificates Under International Convention for Safety of Life at Sea, 1974 ¦ 31.40-40 Duration of Convention certificatesŚT/ALL....
46 CFR 31.40-40 - Duration of Convention certificates-T/ALL.
Code of Federal Regulations, 2011 CFR
...2011-10-01 false Duration of Convention certificates-T/ALL. 31.40-40... Certificates Under International Convention for Safety of Life at Sea, 1974 ¦ 31.40-40 Duration of Convention certificatesŚT/ALL....
15 CFR Supplement No. 1 to Part 716 - Notification, Duration and Frequency of Inspections
Code of Federal Regulations, 2011 CFR
...Notification, Duration and Frequency of Inspections No. Supplement No. 1 to Part 716 Commerce and Foreign Trade Regulations...DECLARED FACILITIES Pt. 716, Supp. 1 Supplement No. 1 to Part 716ŚNotification, Duration and...
45 CFR 160.205 - Duration of effectiveness of exception determinations.
Code of Federal Regulations, 2010 CFR
... 2010-10-01 2010-10-01 false Duration of effectiveness of exception determinations. 160.205 Section 160...REQUIREMENTS Preemption of State Law ¦ 160.205 Duration of effectiveness of exception determinations. An exception granted...
Reciprocity in long pulse duration laser interactions with polymers
NASA Astrophysics Data System (ADS)
Marchant, A. L.; Snelling, H. V.
The laser irradiation of polyimide Kapton HN (PI), polyetheretherketone (PEEK), polyethyleneterephthalate (PET) and polypropylene (PP) by long pulse, radio frequency excited, CO2 laser radiation has been studied. In the pulse duration range 47-757 Ąs the minimum pulse energy required to damage the surface is found to be independent of exposure time. Hence, the threshold fluence is also independent of pulse duration; the same effect is achieved through the application of long pulses at low irradiance as shorter ones at higher irradiance. The values of these threshold fluences have been found to be 8.15 J cm-2, 5.36 J cm-2, 3.39 J cm-2 and 9.63 J cm-2 for PI, PEEK, PET and PP, respectively. The details of this behaviour have been analysed through calculations of the laser-induced temperature rise and the application of an Eyring-type rate law for the thermal decomposition of polyimide and PEEK and by considering the melting points of PP and PET.
Factors associated with methadone treatment duration: a Cox regression analysis.
Lin, Chao-Kuang; Hung, Chia-Chun; Peng, Ching-Yi; Chao, En; Lee, Tony Szu-Hsien
This study examined retention rates and associated predictors of methadone maintenance treatment (MMT) duration among 128 newly admitted patients in Taiwan. A semi-structured questionnaire was used to obtain demographic and drug use history. Daily records of methadone taken and test results for HIV, HCV, and morphine toxicology were taken from a computerized medical registry. Cox regression analyses were performed to examine factors associated with MMT duration. MMT retention rates were 80.5%, 68.8%, 53.9%, and 41.4% for 3, 6, 12, and 18 months, respectively. Excluding 38 patients incarcerated during the study period, retention rates were 81.1%, 73.3%, 61.1%, and 48.9% for 3 months, 6 months, 12 months, and 18 months, respectively. No participant seroconverted to HIV and 1 died during the 18-months follow-up. Results showed that being female, imprisonment, a longer distance from house to clinic, having a lower methadone dose after 30 days, being HCV positive, and in the New Taipei city program predicted early patient dropout. The findings suggest favorable MMT outcomes of HIV seroincidence and mortality. Results indicate that the need to minimize travel distance and to provide programs that meet women's requirements justify expansion of MMT clinics in Taiwan. PMID:25875531
Moving Time: The Influence of Action on Duration Perception
Perceiving the sensory consequences of action accurately is essential for appropriate interaction with our physical and social environments. Prediction mechanisms are considered necessary for fine-tuned sensory control of action, yet paradoxically may distort perception. Here, we examine this paradox by addressing how movement influences the perceived duration of sensory outcomes congruent with action. Experiment 1 required participants to make judgments about the duration of vibrations applied to a moving or stationary finger. In Experiments 2 and 3, participants judged observed finger movements that were congruent or incongruent with their own actions. In all experiments, target events were perceived to be longer when congruent with movement. Interestingly, this temporal dilation did not differ as a function of stimulus perspective (1st or 3rd person) or spatial location. We propose that this bias may reflect the operation of an adaptive mechanism for sensorimotor selection and control that preactivates anticipated outcomes of action. The bias itself may have surprising implications for both action control and perception of others: we may be in contact with grasped objects for less time than we realize, and othersÆ reactions to us may be briefer than we believe. PMID:25089534
Duration of breastfeeding and serum PCB 153 concentrations in children.
Lancz, Kinga; Hertz-Picciotto, Irva; Jusko, Todd A; MurĒnovß, Lubica; Wimmerovß, So?a; Sov?Ēkovß, Eva; DedĒk, Ladislav; Strķmy, Maximilißn; Drobnß, Beata; FarkaÜovß, Dana; Trnovec, TomßÜ
Polychlorinated biphenyls (PCBs) are toxic, persistent, and bioaccumulative chemicals which, because of their lipophilic properties, are abundant in human breast milk. Breastfed infants are therefore at risk of being exposed to considerable amounts of PCBs. The commonly used exposure estimations, based solely on breast milk PCB levels and duration of breastfeeding, may lead to exposure misclassification. To improve assessments of exposure to PCBs, we determined PCB 153 serum concentration, as a model substance for PCBs, at the critical time of weaning for each child in 305 breastfed infants from 5 single time point concentration measurements spread over 7 years and data on duration of breastfeeding, using an earlier developed model of the system type. We approximated the dependence of PCB 153 serum concentration, Ctbf, adjusted to cord serum concentration, C0, on nursing period, by a polynomial function Ctbf/C0=0.596+0.278t-0.0047t(2) which reliably predicts exposure to PCB 153 of breastfed infants, important for assessment of dose-outcome relationships. Adjustment of current serum concentrations to cord serum concentration improved validity of exposure assessment. PMID:25460618
Activities for a long duration flight system in Japan
NASA Astrophysics Data System (ADS)
Nishimura, J.
The balloon group in the Institute of Space and Astronomical Science (ISAS) has been spending many efforts to long duration balloon flights for scientific observations. One of those achievements is the of Boomerang Balloon system. The system has been successfully applied to many scientific observations in Japan during these 20 years. Recent achievements along this line are ``Satellite linked Boomerang Balloons'' This is to recover the payloads after several days of flights over the Pacific Ocean. ISAS and the Communication Research Laboratory have been conducting this program. The Polar Patrol Balloon at Antarctica has been established already to perform the circumpolar flight at level altitude taking almost 3 weeks. The National Institute for Polar Research and ISAS have been conducting this program. Summarizing those activities, in this paper we mainly refer to some recent results of feasibility studies of the Over Pressurized Pumpkin Shaped Balloons and of the balloons with new possible balloon films (EVAL, Ethylene-Vinyl-Alcohol) of specific IR absorptivity for the long duration flights.
Influence of Preoperative Pain Duration on Microsurgical Varicocelectomy Outcomes
K÷se, Mustafa G÷khan; ųnem, Kadir; Ūetinkaya, Mehmet; Karada?, Erkan; Arpali, Emre
Objective. To investigate the question of whether duration of pain before surgery ultimately affects sperm parameters after varicocelectomy. Methods. Fifty patients with painful grade-3 varicocele were investigated prospectively. The patients were divided into two groups according to their symptom period. The patients having had grade-3 varicocele for less than 1 year were included in Group-1 (Ge, n = 25). Twenty-five patients who had painful grade-3 varicocele for more than 1 year (Gs, n = 25) were classified in Group-2. Semen analysis was performed after 3 days of sexual abstinence twice a month. Total sperm concentration (TSC), rapidly progressive motility (SPa), and slow or sluggish motility (SPb) rates were noted. Pain was evaluated by using 10?cm visual analogue scale (VAS). Results. Postoperative TSC and %SPb were significantly higher in both groups (P = 0.01). There was no difference between two groups for preoperative and postoperative TSC, %SPa, % and SPb values. VAS significantly declined in both groups (P = 0.005). This postoperative decline was not significant for intergroup comparison. Conclusions. Our results show that increase in semen quality and decrease in the pain after microsurgery varicocelectomy do not depend on the duration of the preoperative pain. PMID:24454350
Advanced Water Recovery Technologies for Long Duration Space Exploration Missions
NASA Technical Reports Server (NTRS)
Liu, Scan X.
Extended-duration space travel and habitation require recovering water from wastewater generated in spacecrafts and extraterrestrial outposts since the largest consumable for human life support is water. Many wastewater treatment technologies used for terrestrial applications are adoptable to extraterrestrial situations but challenges remain as constraints of space flights and habitation impose severe limitations of these technologies. Membrane-based technologies, particularly membrane filtration, have been widely studied by NASA and NASA-funded research groups for possible applications in space wastewater treatment. The advantages of membrane filtration are apparent: it is energy-efficient and compact, needs little consumable other than replacement membranes and cleaning agents, and doesn't involve multiphase flow, which is big plus for operations under microgravity environment. However, membrane lifespan and performance are affected by the phenomena of concentration polarization and membrane fouling. This article attempts to survey current status of membrane technologies related to wastewater treatment and desalination in the context of space exploration and quantify them in terms of readiness level for space exploration. This paper also makes specific recommendations and predictions on how scientist and engineers involving designing, testing, and developing space-certified membrane-based advanced water recovery technologies can improve the likelihood of successful development of an effective regenerative human life support system for long-duration space missions.
Duration versus response to space-flight exposure
NASA Technical Reports Server (NTRS)
Leach, Carolyn S.
The duration of human expeditions into space has been as short as a few hours and as long as a year, and although we still need much more information, we can identify some trends indicating effects of flight duration on the physiologic response to space flight. Evidence suggests that after a period of dynamic change that varies for each physiologic system, some physiologic variable stabilize at levels that may differ from those at 1 G. Other variables appear to undergo change from time to time even after months in space, and others have not been observed to reach a plateau. Effects on the neurovestibular system begin very early and certain ones diminish rapidly. Effects of weightlessness on fluid and electrolyte physiology appear to reach a peak after that of neurophysiologic effects. It is possible that the initial responses of these two systems follow a more similar time course than is now apparent. Responses of the cardiovascular system reach a peak that approaches clinical significance after about 3 weeks. The mass of red blood cells is maximally altered after about a month. Bone mineral and lean body mass are lost gradually for at least 6 months, perhaps longer.
Word-Initial Letters Influence Fixation Durations during Fluent Reading
Hand, Christopher J.; OÆDonnell, Patrick J.; Sereno, Sara C.
The present study examined how word-initial letters influence lexical access during reading. Eye movements were monitored as participants read sentences containing target words. Three factors were independently manipulated. First, target words had either high or low constraining word-initial letter sequences (e.g., dwarf or clown, respectively). Second, targets were either high or low in frequency of occurrence (e.g., train or stain, respectively). Third, targets were embedded in either biasing or neutral contexts (i.e., targets were high or low in their predictability). This 2 (constraint)?ū?2 (frequency)?ū?2 (context) design allowed us to examine the conditions under which a wordÆs initial letter sequence could facilitate processing. Analyses of fixation duration data revealed significant main effects of constraint, frequency, and context. Moreover, in measures taken to reflect ōearlyö lexical processing (i.e., first and single fixation duration), there was a significant interaction between constraint and context. The overall pattern of findings suggests lexical access is facilitated by highly constraining word-initial letters. Results are discussed in comparison to recent studies of lexical features involved in word recognition during reading. PMID:22485100
Analysis of Fermi Gamma-Ray Burst duration distribution
Tarnopolski, Mariusz
Two classes of GRBs, short and long, have been determined without any doubts, and are usually prescribed to different physical scenarios. A third class, intermediate in $T_{90}$ durations, has been reported to be present in the datasets of BATSE, Swift, RHESSI and possibly BeppoSAX. The latest release of $>1500$ GRBs observed by Fermi gives an opportunity to further investigate the duration distribution. The aim of this paper is to investigate whether a third class is present in the $\\log T_{90}$ distribution, or is it described by a bimodal distribution. A standard $\\chi^2$ fitting of a mixture of Gaussians is applied to 25 histograms with different binnings. Different binnings give various values of the fitting parameters, as well as the shape of the fitted curve. Among five statistically significant fits none is trimodal. Locations of the Gaussian components are in agreement with previous works. However, a trimodal distribution, understood in the sense of having three separated peaks, is not found for any ...
Control of qubits by shaped pulses of finite duration
NASA Astrophysics Data System (ADS)
Boradjiev, Iavor I.; Vitanov, Nikolay V.
We consider the interaction of a two-state quantum system with a class of pulses of finite temporal duration. The pulse shape function f(t) of such a pulse is a nonanalytic function of time, with discontinuous derivatives at the turn-on and turn-off times. The excitation line widthŚthe excited-state population versus the detuningŚis determined primarily by the magnitude of the jumps of the derivative f(n)(t) at the points of nonanalyticity, where n is the order of the first discontinuous derivative; this nonanalyticity shows up in the nth superadiabatic basis. The excitation line width for such pulses exhibits weak power broadeningŚit scales up as ?01/(n+1), where ?0 is the peak Rabi frequency of the transition: ?(t)=?0f(t). As a specific example, we consider the power-of-sine class f(t)=sinn(?t/T) (0?t?T) and a truncated Gaussian pulse, and we compare their excitation line widths with the well-known excitation profile of the rectangular pulse (the Rabi formula). We find that, because of the reduced power broadening, the sinn and truncated Gaussian pulses may accelerate manipulation of qubits compared to rectangular pulses. The reason is that the lower power broadening allows one to use higher Rabi frequency, and hence shorter pulse duration, without affecting significantly other closely lying states.
Intercultural crew issues in long-duration spaceflight
NASA Technical Reports Server (NTRS)
Kraft, Norbert O.; Lyons, Terence J.; Binder, Heidi
Before long-duration flights with international crews can be safely undertaken, potential interpersonal difficulties will need to be addressed. Crew performance breakdown has been recognized by the American Institute of Medicine, in scientific literature, and in popular culture. However, few studies of human interaction and performance in confined, isolated environments exist, and the data pertaining to those studies are mostly anecdotal. Many incidents involving crew interpersonal dynamics, those among flight crews, as well as between flight crews and ground controllers, are reported only in non-peer reviewed books and newspapers. Consequently, due to this lack of concrete knowledge, the selection of astronauts and cosmonauts has focused on individual rather than group selection. Additional selection criteria such as interpersonal and communication competence, along with intercultural training, will have a decisive impact on future mission success. Furthermore, industrial psychological research has demonstrated the ability to select a group based on compatibility. With all this in mind, it is essential to conduct further research on heterogeneous, multi-national crews including selection and training for long-duration space missions.
Statistical study of observed and intrinsic durations among BATSE and Swift/BAT GRBs
NASA Astrophysics Data System (ADS)
Zitouni, H.; Guessoum, N.; Azzam, W. J.; Mochkovitch, R.
Studies of BATSE bursts (Kouveliotou et al. 1993) have resulted in the widespread adoption of a two-group categorization: long bursts (those with durations ?2 seconds) and short bursts (those with durations ?2 seconds). This categorization, one must recall, used the observed T 90 time durations for bursts (during which 90 % of a burst's fluence is measured).
Effects of Resource Allocation Policies for Reducing Project Durations: A Systems Modelling Approach
Zee Woon Lee; David N. Ford; Nitin Joglekar
Minimizing duration is critical to success in many development projects. Resource allocation policies during such projects determine the fractions of resources that are to be assigned to constituent tasks. The choice of allocation policy can strongly influence project durations. But policies for reduced project duration are difficult to design and implement because of closed loop flows of work that generate
Effect of Duration of Teat Cup Liner Closure Per Pulsation Cycle on Bovine Mastitis
S. Y. Reitsma; E. J. CANTfl; R. J. Grindal; D. R. Westgarth; A. J. Bramley
Measurements of teat end expansion and contraction times from step changes in pressure suggest that teat ends require a minimal duration of liner closure for response. Effect of duration of liner closure per pulsation cycle on suscepti- bility of the udder to infection was tested. Four durations of liner closure (liner more than half closed) were applied: zero, .17, .34,
Duration, Distance, and Speed Judgments of Two Moving Objects by 4- to 11-Year-Olds.
ERIC Educational Resources Information Center
Matsuda, Fumiko
Four- to 11-year-olds made duration, distance, and speed judgments on Piagetian tasks where cars ran on parallel tracks. Among younger children, duration and distance judgments had approximately the same difficulty. Among older children, distance judgments were easier than duration judgments, and symmetry of effects of temporal and spatialģ
Marked Exacerbation of Orthostatic Intolerance After Long-vs. Short-Duration Spaceflight in Veteran Astronauts
their previous short Shuttle flights; and second, compari- sons were made with tilt test data from 20 astronauts after short-duration flights. We also compared the long-duration flight tilt test data to tilt test data who flew on the short Shuttle flights that delivered and recovered the long-duration astronauts
Duration selectivity organization in the inferior colliculus of the big brown bat, Eptesicus fuscus.
Jen, Philip H-S; Wu, Chung Hsin
Duration selectivity of auditory neurons plays an important role in sound recognition. Previous studies show that GABA-mediated duration selectivity of neurons in the central nucleus of the inferior colliculus (IC) of many animal species behave as band-, short-, long- and all-pass filters to sound duration. The present study examines the organization of duration selectivity of IC neurons of the big brown bat, Eptesicus fuscus, in relation to graded spatial distribution of GABA(A) receptors, which are mostly distributed in the dorsomedial region of the IC but are sparsely distributed in the ventrolateral region. Duration selectivity of IC neuron is studied before and during iontophoretic application of GABA and its antagonist, bicuculline. Bicuculline application decreases and GABA application increases duration selectivity of IC neurons. Bicuculline application produces more pronounced broadening of the duration tuning curves of neurons at upper IC than at deeper IC but the opposite is observed during GABA application. The best duration of IC neurons progressively lengthens and duration selectivity decreases with recording depth both before and during drug application. As such, low best frequency neurons at upper IC have shorter best duration and sharper duration selectivity than high best frequency neurons in the deeper IC have. These data suggest that duration selectivity of IC neurons systematically varies with GABA(A) receptor distribution gradient within the IC. PMID:16828465
A Competing Risks Analysis of Strike Duration in Spain: Agreement and Non-Agreement Outcomes
Silviano Esteve Pķrez; Mariluz Marco Aledo
This paper analyses the determinants of strike duration in Spain taking into account different outcomes (agreement and non-agreement). We find that duration decreases with the number of strikers or several applicable agreements to strike units. It rises with minimum services, the degree of strike support and in private firms. With respect to the real GDP growth rate, duration is pro-cyclical
Cognitive Abilities Explaining Age-Related Changes in Time Perception of Short and Long Durations
ERIC Educational Resources Information Center
Zelanti, Pierre S.; Droit-Volet, Sylvie
The current study investigated how the development of cognitive abilities explains the age-related changes in temporal judgment over short and long duration ranges from 0.5 to 30 s. Children (5- and 9-year-olds) as well as adults were given a temporal bisection task with four different duration ranges: a duration range shorter than 1 s, twoģ
A Multiplicative Model of the Utility of Survival Duration and Health Quality
John M. Miyamoto; Stephen A. Eraker
Survival duration and health quality are fundamentally important aspects of health. A utility model for survival duration and health quality is a model of the subjective value of these attributes. We investigate the hypothesis that the utility (subjective value) of survival duration and health quality is determined by a multiplicative model. According to this model, there are separate subjective scales
A multiplicative model of the utility of survival duration and health quality
John M. Miyamoto; Stephen A. Eraker
SUMMARY Survival duration and health quality are fundamentally important aspects of health. A utility model for survival duration and health quality is a model of the subjective value of these attributes. We investigate the hypothesis that the utility (subjective value) of survival duration and health quality is determined by a multiplicative model. According to this model, there are separate subjective
A neural hierarchy for illusions of time: Duration adaptation precedes multisensory integration
Heron, James; Hotchkiss, John; Aaen-Stockdale, Craig; Roach, Neil W.; Whitaker, David
Perceived time is inherently malleable. For example, adaptation to relatively long or short sensory events leads to a repulsive aftereffect such that subsequent events appear to be contracted or expanded (duration adaptation). Perceived visual duration can also be distorted via concurrent presentation of discrepant auditory durations (multisensory integration). The neural loci of both distortions remain unknown. In the current study we use a psychophysical approach to establish their relative positioning within the sensory processing hierarchy. We show that audiovisual integration induces marked distortions of perceived visual duration. We proceed to use these distorted durations as visual adapting stimuli yet find subsequent visual duration aftereffects to be consistent with physical rather than perceived visual duration. Conversely, the concurrent presentation of adapted auditory durations with nonadapted visual durations results in multisensory integration patterns consistent with perceived, rather than physical, auditory duration. These results demonstrate that recent sensory history modifies human duration perception prior to the combination of temporal information across sensory modalities and provides support for adaptation mechanisms mediated by duration selective neurons situated in early areas of the visual and auditory nervous system (Aubie, Sayegh, & Faure, 2012; Duysens, Schaafsma, & Orban, 1996; Leary, Edwards, & Rose, 2008). PMID:24306853
Regulation of signal duration and the statistical dynamics of kinase activation by scaffold proteins
Jason W. Locasale; Arup K. Chakraborty
Scaffolding proteins that direct the assembly of multiple kinases into a spatially localized signaling complex are often essential for the maintenance of an appropriate biological response. Although scaffolds are widely believed to have dramatic effects on the dynamics of signal propagation, the mechanisms that underlie these consequences are not well understood. Here, Monte Carlo simulations of a model kinase cascade are used to investigate how the temporal characteristics of signaling cascades can be influenced by the presence of scaffold proteins. Specifically, we examine the effects of spatially localizing kinase components on a scaffold on signaling dynamics. The simulations indicate that a major effect that scaffolds exert on the dynamics of cell signaling is to control how the activation of protein kinases is distributed over time. Scaffolds can influence the timing of kinase activation by allowing for kinases to become activated over a broad range of times, thus allowing for signaling at both early and late times. Scaffold concentrations that result in optimal signal amplitude also result in the broadest distributions of times over which kinases are activated. These calculations provide insights into one mechanism that describes how the duration of a signal can potentially be regulated in a scaffold mediated protein kinase cascade. Our results illustrate another complexity in the broad array of control properties that emerge from the physical effects of spatially localizing components of kinase cascades on scaffold proteins.
Margot Scholte
SamenvattingĀĀIk ben al enige tijd gefascineerd door æcomplexe oplossingenÆ. Complexe oplossingen zijn oplossingen die qua complexiteit\\u000a niet in verhouding staan tot het ervaren probleem. Denk aan de paarse krokodil: je ziet je verloren opblaasbeest achter glas,\\u000a maar je mag hem niet meenemen, voordat je aan alle procedures hebt voldaan.
NASA Astrophysics Data System (ADS)
Battiston, Stefano; Caldarelli, Guido; Georg, Co-Pierre; May, Robert; Stiglitz, Joseph
The intrinsic complexity of the financial derivatives market has emerged as both an incentive to engage in it, and a key source of its inherent instability. Regulators now faced with the challenge of taming this beast may find inspiration in the budding science of complex systems.
ERIC Educational Resources Information Center
Glanville, Ranulph
This article considers the nature of complexity and design, as well as relationships between the two, and suggests that design may have much potential as an approach to improving human performance in situations seen as complex. It is developed against two backgrounds. The first is a world view that derives from second order cybernetics and radicalģ
Marked exacerbation of orthostatic intolerance after long- vs. short-duration spaceflight in veteran astronauts
NASA Technical Reports Server (NTRS)
Meck, J. V.; Reyes, C. J.; Perez, S. A.; Goldberger, A. L.; Ziegler, M. G.
OBJECTIVE: The incidence of postflight orthostatic intolerance after short-duration spaceflight is about 20%. However, the incidence after long-duration spaceflight was unknown. The purpose of this study was to test the hypothesis that orthostatic intolerance is more severe after long-duration than after short-duration flight. METHODS: We performed tilt tests on six astronauts before and after long-duration (129-190 days) spaceflights and compared these data with data obtained during stand tests before and after previous short-duration missions. RESULTS: Five of the six astronauts studied became presyncopal during tilt testing after long-duration flights. Only one had become presyncopal during stand testing after short-duration flights. We also compared the long-duration flight tilt test data to tilt test data from 20 different astronauts who flew on the short-duration Shuttle missions that delivered and recovered the astronauts to and from the Mir Space Station. Five of these 20 astronauts became presyncopal on landing day. Heart rate responses to tilt were no different between astronauts on long-duration flights and astronauts on short-duration flights, but long-duration subjects had lower stroke volumes and cardiac outputs than short-duration presyncopal subjects, suggesting a possible decrease in cardiac contractile function. One subject had subnormal norepinephrine release with upright posture after the long flight but not after the short flight. Plasma volume losses were not greater after long flights. CONCLUSION: Long-duration spaceflight markedly increases orthostatic intolerance, probably with multiple contributing factors.
Polarization and scattering of a long-duration meteor trail
NASA Astrophysics Data System (ADS)
Close, S.; Kelley, M.; Vertatschitsch, L.; Colestock, P.; Oppenheim, M.; Yee, J.
High-power, large-aperture (HPLA) radars have been used over the past two decades to characterize the plasmas formed both around and behind meteoroids as they enter Earth's atmosphere. These plasmas, referred to as heads and trails, respectively, occur with relative frequency (peak head echo detection rate of ś1/s) but are extremely diverse and have been difficult to define in a general sense. One particular type of plasma, referred to as the nonspecular trail, occurs when the meteoroid travels quasi-parallel to the radar beam with the radar beam lying quasi-perpendicular to the background magnetic field. Reflection is believed to occur from field-aligned irregularities (FAIs) that form after the trail becomes unstable. While FAI scattering pertains to the majority of nonspecular trails that are short in duration, a subset of these trails, referred to as long-duration trails, still remains open to interpretation. In this paper we present a case study analysis of a long-duration, nonspecular trail and its associated head echo detected with the Advanced Research Project Agency (ARPA) Long-Range Tracking and Identification Radar (ALTAIR), which is an HPLA radar. These data are unique in that they are high resolution (with monopulse angles), dual frequency, and, most importantly, dual polarized, which allows for unprecedented insight into the scattering process from both heads and trails. First, we determine the velocity and mass of the parent meteoroid, which is a particle weighing more than a milligram and is one of the largest meteoroids ever detected by ALTAIR. Second, we determine the peak plasma density and polarization of the head echo and characterize the unique, yet strong returns in the opposite polarization, which may be due to multiple scattering centers within the range gate. Finally, we examine the polarization properties of the trail and discuss the first conclusive evidence of polarization flipping along the trail striations, which we believe corresponds to sharp gradients at the edges of the trail related to turbulent mixing of a dusty plasma that is elongating along the magnetic field. We look into a new idea, namely, the notion that some nonspecular echoes might correspond to a high Schmidt number, dusty plasma, as is found in and above noctilucent clouds. Our results show how polarized return can aid in scattering diagnostics and that single polarization radars must be used with caution for determining head and trail plasma densities given that some of the return can occur in the ōunexpectedö channel.
Dependency of magnetocardiographically determined fetal cardiac time intervals on gestational age, gender and postnatal biometrics in healthy pregnancies
van Leeuwen, Peter; Lange, Silke; Klein, Anita; Geue, Daniel; Gr÷nemeyer, Dietrich HW
Background Magnetocardiography enables the precise determination of fetal cardiac time intervals (CTI) as early as the second trimester of pregnancy. It has been shown that fetal CTI change in course of gestation. The aim of this work was to investigate the dependency of fetal CTI on gestational age, gender and postnatal biometric data in a substantial sample of subjects during normal pregnancy. Methods A total of 230 fetal magnetocardiograms were obtained in 47 healthy fetuses between the 15th and 42nd week of gestation. In each recording, after subtraction of the maternal cardiac artifact and the identification of fetal beats, fetal PQRST courses were signal averaged. On the basis of therein detected wave onsets and ends, the following CTI were determined: P wave, PR interval, PQ interval, QRS complex, ST segment, T wave, QT and QTc interval. Using regression analysis, the dependency of the CTI were examined with respect to gestational age, gender and postnatal biometric data. Results Atrioventricular conduction and ventricular depolarization times could be determined dependably whereas the T wave was often difficult to detect. Linear and nonlinear regression analysis established strong dependency on age for the P wave and QRS complex (r2 = 0.67, p < 0.001 and r2 = 0.66, p < 0.001) as well as an identifiable trend for the PR and PQ intervals (r2 = 0.21, p < 0.001 and r2 = 0.13, p < 0.001). Gender differences were found only for the QRS complex from the 31st week onward (p < 0.05). The influence on the P wave or QRS complex of biometric data, collected in a subgroup in whom recordings were available within 1 week of birth, did not display statistical significance. Conclusion We conclude that 1) from approximately the 18th week to term, fetal CTI which quantify depolarization times can be reliably determined using magnetocardiography, 2) the P wave and QRS complex duration show a high dependency on age which to a large part reflects fetal growth and 3) fetal gender plays a role in QRS complex duration in the third trimester. Fetal development is thus in part reflected in the CTI and may be useful in the identification of intrauterine growth retardation. PMID:15061871
Angry Birds Space Encounter - Duration: 4 minutes, 47 seconds.
At NASA's Kennedy Space Center Visitor Complex in Florida, a grand opening celebration was held for the new Angry Birds Space Encounter, March 22. Finland-based Rovio Entertainment, the creator of ...
FAITH Water Channel Flow Visualization - Duration: 56 seconds.
Water channel flow visualization experiments are performed on a three dimensional model of a small hill. This experiment was part of a series of measurements of the complex fluid flow around the hi...
NASA Now: Expedition 26 - Duration: 7 minutes, 10 seconds.
In this installment of NASA Now, meet associate International Space Station program scientist Tara Ruttley, who talks about the complexity of conducting research from this one-of-a-kind orbiting sc...
A Global Partnership for All Mankind - Duration: 108 seconds.
Learn how people from different countries and cultures from all around the world came together to design, manufacture, build, and operate the most complex and challenging engineering project in the...
Supercomputing the Climate - Duration: 5 minutes, 43 seconds.
Goddard Space Flight Center is the home of a state-of-the-art supercomputing facility called the NASA Center for Climate Simulation (NCCS) that is capable of running highly complex models to help s...
Atlantis Moves to New Home - Duration: 2 minutes, 51 seconds.
Space shuttle Atlantis makes a 10-mile trek from the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida to the Kennedy Space Center Visitor Complex where it will be put on public d...
Launch of Juno! - Duration: 2 minutes, 11 seconds.
An Atlas V rocket lofted the Juno spacecraft toward Jupiter from Space Launch Complex-41. The 4-ton Juno spacecraft will take five years to reach Jupiter on a mission to study its structure and dec...
Gateway to New Atlantis Attraction Takes Shape - Duration: 61 seconds.
The home of space shuttle Atlantis continues taking shape at the Kennedy Space Center Visitor Complex. Crews placed the nose cone atop the second of a replica pair of solid rocket boosters. A life-...
CloudSat and CALIPSO Help Meteorology - Duration: 24 seconds.
The study of meteorology presents significant challenges to scientists. One of the most challenging aspects is the inherent complexity of weather coupled with its high rate of change. In the case o...
CCP: Sierra Nevada Captive-Carry Test - Duration: 65 seconds.
Sierra Nevada Corporation (SNC) Space System's Dream Chaser design passed one of its most complex tests to date with a successful captive-carry test conducted near the Rocky Mountain Metropolitan A...
FAITH 3-D Particle Image Velocimetry - Duration: 10 seconds.
Instantaneous velocity (30 frames at 1 Hz) measurements of a three dimensional model of a small hill in fluid flow. This experiment was part of a series of measurements of the complex fluid flow ar...
Morpheus Lander Hot Fire Test - Duration: 51 seconds.
This video shows a successful "hot fire" test of the Morpheus lander on February 27, 2012, at the VTB Flight Complex at NASA's Johnson Space Center. The engine burns for an extended period of time ...
Scaling of lunge feeding in rorqual whales: an integrated model of engulfment duration.
Potvin, J; Goldbogen, J A; Shadwick, R E
Rorqual whales (Balaenopteridae) obtain their food by lunge feeding, a dynamic process that involves the intermittent engulfment and filtering of large amounts of water and prey. During a lunge, whales accelerate to high speed and open their mouth wide, thereby exposing a highly distensible buccal cavity to the flow and facilitating its inflation. Unsteady hydrodynamic models suggest that the muscles associated with the ventral groove blubber undergo eccentric contraction in order to stiffen and control the inflation of the buccal cavity; in doing so the engulfed water mass is accelerated forward as the whale's body slows down. Although the basic mechanics of lunge feeding are relatively well known, the scaling of this process remains poorly understood, particularly with regards to its duration (from mouth opening to closure). Here we formulate a new theory of engulfment time which integrates prey escape behavior with the mechanics of the whale's body, including lunge speed and acceleration, gape angle dynamics, and the controlled inflation of the buccal cavity. Given that the complex interaction between these factors must be highly coordinated in order to maximize engulfment volume, the proposed formulation rests on the scenario of Synchronized Engulfment, whereby the filling of the cavity (posterior to the temporomandibular joint) coincides with the moment of maximum gape. When formulated specifically for large rorquals feeding on krill, our analysis predicts that engulfment time increases with body size, but in amounts dictated by the specifics of krill escape and avoidance kinematics. The predictions generated by the model are corroborated by limited empirical data on a species-specific basis, particularly for humpback and blue whales chasing krill. A sensitivity analysis applied to all possible sized fin whales also suggests that engulfment duration and lunge speed will increase intra-specifically with body size under a wide range of predator-prey scenarios. This study provides the theoretical framework required to estimate the scaling of the mass-specific drag being generated during engulfment, as well as the energy expenditures incurred. PMID:20816685
Site-specific PEGylation of human thyroid stimulating hormone to prolong duration of action.
Qiu, Huawei; Boudanova, Ekaterina; Park, Anna; Bird, Julie J; Honey, Denise M; Zarazinski, Christine; Greene, Ben; Kingsbury, Jonathan S; Boucher, Susan; Pollock, Julie; McPherson, John M; Pan, Clark Q
Recombinant human thyroid stimulating hormone (rhTSH or Thyrogen) has been approved for thyroid cancer diagnostics and treatment under a multidose regimen due to its short circulating half-life. To reduce dosing frequency, PEGylation strategies were explored to increase the duration of action of rhTSH. Lysine and N-terminal PEGylation resulted in heterogeneous product profiles with 40% or lower reaction yields of monoPEGylated products. Eleven cysteine mutants were designed based on a structure model of the TSH-TSH receptor (TSHR) complex to create unique conjugation sites on both ? and ? subunits for site-specific conjugation. Sequential screening of mutant expression level, oligomerization tendency, and conjugation efficiency resulted in the identification of the ?G22C rhTSH mutant for stable expression and scale-up PEGylation. The introduced cysteine in the ?G22C rhTSH mutant was partially blocked when isolated from conditioned media and could only be effectively PEGylated after mild reduction with cysteine. This produced a higher reaction yield, ~85%, for the monoPEGylated product. Although the mutation had no effect on receptor binding, PEGylation of ?G22C rhTSH led to a PEG size-dependent decrease in receptor binding. Nevertheless, the 40 kDa PEG ?G22C rhTSH showed a prolonged duration of action compared to rhTSH in a rat pharmacodynamics model. Reverse-phase HPLC and N-terminal sequencing experiments confirmed site-specific modification at the engineered Cys 22 position on the ?-subunit. This work is another demonstration of successful PEGylation of a cysteine-knot protein by an engineered cysteine mutation. PMID:23350694
Camouflage mismatch in seasonal coat color due to decreased snow duration
Mills, L. Scott; Zimova, Marketa; Oyler, Jared; Running, Steven; Abatzoglou, John T.; Lukacs, Paul M.
Most examples of seasonal mismatches in phenology span multiple trophic levels, with timing of animal reproduction, hibernation, or migration becoming detached from peak food supply. The consequences of such mismatches are difficult to link to specific future climate change scenarios because the responses across trophic levels have complex underlying climate drivers often confounded by other stressors. In contrast, seasonal coat color polyphenism creating camouflage against snow is a direct and potentially severe type of seasonal mismatch if crypsis becomes compromised by the animal being white when snow is absent. It is unknown whether plasticity in the initiation or rate of coat color change will be able to reduce mismatch between the seasonal coat color and an increasingly snow-free background. We find that natural populations of snowshoe hares exposed to 3 y of widely varying snowpack have plasticity in the rate of the spring white-to-brown molt, but not in either the initiation dates of color change or the rate of the fall brown-to-white molt. Using an ensemble of locally downscaled climate projections, we also show that annual average duration of snowpack is forecast to decrease by 29¢35 d by midcentury and 40¢69 d by the end of the century. Without evolution in coat color phenology, the reduced snow duration will increase the number of days that white hares will be mismatched on a snowless background by four- to eightfold by the end of the century. This novel and visually compelling climate change-induced stressor likely applies to >9 widely distributed mammals with seasonal coat color. PMID:23589881
Will Toxic Amounts of Lead be Released from Astronauts' Bones During Long Duration Missions?
NASA Astrophysics Data System (ADS)
Garcia, H. D.
Toxic contaminants in the air, water, or food are a source of concern, both on Earth and in spacecraft. In microgravity, however, another source of potential toxicants can be introduced: astronauts' bones. Space toxicologists have been concerned about the possibility that crew members of long duration missions could suffer from lead poisoning due to the release of lead into their blood from stores of lead in their bones. If this occurs, NASA would be unable to set a Spacecraft Water Exposure Guideline (SWEG) for permissible lead concentrations in spacecraft drinking water that would be protective of astronaut health. Lead ingested earlier in life is stored in the bones where it can remain for many years without causing toxicity unless something happens to cause the release of lead into the blood. Microgravity is known to accelerate bone resorption, leading to the release of calcium and lead from bones into the blood. Relatively small increases in the concentration of lead in the blood can cause toxic effects in a variety of organ systems including the brain and kidneys. One mathematical model [1] of the rate of release of lead from bones in microgravity predicts that blood lead levels (BLLs) exceeding the current level of concern for adults (25 Ąg/dL) could be achieved within about 100 days in microgravity in some astronauts. Another, more complex mathematical model [2], however, predicts a much more limited release of lead, such that clinically significant concentrations of lead in the blood are not achieved. To determine which of these predictions is more accurate, BLL measurements were taken in a sample of astronauts before and after stays of at least 150 days on the International Space Station. BLLs measured before flight and compared to BLLs upon landing confirmed that no measurable increases in BLLs are observed in crew members of long-duration missions. In all astronauts tested, BLLs were below the U.S. population average of about 2 ?g/dL both before and immediately after long-duration missions in microgravity. Thus, it should be possible to set a SWEG for lead that would protect astronauts against clinically relevant lead poisoning.
An information theoretic study of reduced-complexity receivers for intersymbol interference channels
Abou Faycal, Ibrahim C. (Ibrahim Chafik)
The complexity of the optimal receiver for communications over a discrete-time additive Gaussian intersymbol interference channel typically grows exponentially with the duration of the channel impulse response. Consequently, ...
Managing Action Duration Uncertainty with Just-In-Case Scheduling
NASA Technical Reports Server (NTRS)
Bresina, John; Drummond, Mark; Swanson, Keith
Some applications involve automatic generation and execution of schedules that contain actions with uncertain durations. Such uncertainty can cause schedules to break during execution. This paper presents a technique, called Just-In-Case scheduling or JIC, for building robust schedules that tend not to break. The technique implements the common sense idea of being prepared for likely errors, just in case they should occur. The JIC algorithm analyzes a given schedule, determines where it is likely to break, reinvokes the scheduler to generate a contingent schedule for each highly probable break case, and produces a "multiply contingent" schedule. The technique was developed for a real telescope scheduling problem, and the paper presents empirical results showing that Just-In-Case scheduling performs extremely well for this problem.
Duration Test Report for the SWIFT Wind Turbine
Mendoza, I.; Hur, J.
This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. Three turbines where selected for testing at the National Wind Technology Center (NWTC) as a part of round two of the Small Wind Turbine Independent Testing project. Duration testing is one of up to 5 tests that may be performed on the turbines. Other tests include power performance, safety and function, noise, and power quality. The results of the testing will provide the manufacturers with reports that may be used for small wind turbine certification.
A reexamination of long-duration radial IMF events
NASA Astrophysics Data System (ADS)
Pi, G.; Shue, J. H.; Chao, C. K.; Nemecek, Z.; Safrankova, J.; Lin, C. H.
The radial interplanetary magnetic field (IMF) is one of the special solar wind conditions when the orientation of the IMF is aligned with the solar wind velocity. In this study, we reexamine the solar wind condition during the long-duration radial IMF (>4hrs) using the OMNI solar wind data. During the events, the IMF magnitude, solar wind speed and density, and especially its temperature are depressed in comparison with their yearly averages. In contrast to previous studies, we have found that the total time of the radial IMF per year does not change with solar activity. MHD simulation models failed to predict the location of the magnetopause under the radial IMF condition. A part of the inaccuracy is due to a use of assumed solar wind parameters in the simulations. Here we provide MHD modelers with the real solar wind parameters for simulations of the radial IMF.
Ikhana: A NASA UAS Supporting Long Duration Earth Science Missions
NASA Technical Reports Server (NTRS)
Cobleigh, Brent R.
The NASA Ikhana unmanned aerial vehicle (UAV) is a General Atomics Aeronautical Systems Inc. (San Diego, California) MQ-9 Predator-B modified to support the conduct of Earth science missions for the NASA Science Mission Directorate and, through partnerships, other government agencies and universities. It can carry over 2000 lb of experiment payloads in the avionics bay and external pods and is capable of mission durations in excess of 24 hours at altitudes above 40,000 ft. The aircraft is remotely piloted from a mobile ground control station (GCS) that is designed to be deployable by air, land, or sea. On-board support capabilities include an instrumentation system and an Airborne Research Test System (ARTS). The Ikhana project will complete GCS development, science support systems integration, external pod integration and flight clearance, and operations crew training in early 2007. A large-area remote sensing mission is currently scheduled for Summer 2007.
Workshop on Exercise Prescription for Long-Duration Space Flight
NASA Technical Reports Server (NTRS)
Harris, Bernard A., Jr. (editor); Stewart, Donald F. (editor)
The National Aeronautics and Space Administration has a dedicated history of ensuring human safety and productivity in flight. Working and living in space long term represents the challenge of the future. Our concern is in determining the effects on the human body of living in space. Space flight provides a powerful stimulus for adaptation, such as cardiovascular and musculoskeletal deconditioning. Extended-duration space flight will influence a great many systems in the human body. We must understand the process by which this adaptation occurs. The NASA is agressively involved in developing programs which will act as a foundation for this new field of space medicine. The hallmark of these programs deals with prevention of deconditioning, currently referred to as countermeasures to zero g. Exercise appears to be most effective in preventing the cardiovascular and musculoskeletal degradation of microgravity.
Mixed tumor of female breast of unusual duration and size.
Williams, R W; Leach, W B
A 72-year-old black woman presented with huge enlargement of the right breast beginning approximately 30 years earlier and progressively enlarging over the years. The breast was stony hard, painless, and inconvenient only because of size and weight. Simple mastectomy was done and pathologic examination showed a benign mixed tumor with large areas of pseudocartilage, osteoid, and bone formation. Preoperatively the serum calcium was 11.0 mg/100 ml and alkaline phosphatase, 550 mU/ml (SMA-12). Postoperative course was uneventful and within several weeks the alkaline phosphatase fell to a normal range (35-115 mU/ml). The case presented requires little comment other than its unusual nature and duration. Extensive bone formation was undoubtedly responsible for the elevated alkaline phosphatase and, as expected, it returned to normal limits following excision of the tumor. Simple mastectomy is considered the treatment of choice. PMID:168643
Space Station CMIF extended duration metabolic control test
NASA Technical Reports Server (NTRS)
Schunk, Richard G.; Bagdigian, Robert M.; Carrasquillo, Robyn L.; Ogle, Kathryn Y.; Wieland, Paul O.
The Space Station Extended Duration Metabolic Control Test (EMCT) was conducted at the MSFC Core Module Integration Facility. The primary objective of the EMCT was to gather performance data from a partially-closed regenerative Environmental Control and Life Support (ECLS) system functioning under steady-state conditions. Included is a description of the EMCT configuration, a summary of events, a discussion of anomalies that occurred during the test, and detailed results and analysis from individual measurements of water and gas samples taken during the test. A comparison of the physical, chemical, and microbiological methods used in the post test laboratory analyses of the water samples is included. The preprototype ECLS hardware used in the test, providing an overall process description and theory of operation for each hardware item. Analytical results pertaining to a system level mass balance and selected system power estimates are also included.
Procalcitonin-guided antibiotic therapy duration in critically ill adults.
Walker, Caroline
Procalcitonin is a promising biomarker for antibiotic therapy because its levels rise and fall quickly with bacterial infections. A multidatabase literature search was reviewed with 3 primary prospective randomized control trials used in further analysis. The results indicated that a procalcitonin-guided antibiotic protocol reduces the number of days a patient has to take antibiotics while having no effect on mortality when compared with control groups. Short-term studies did not show a difference in the intensive care unit length of stay, infection relapse rate, superinfection rate, or multidrug-resistant bacteria rate between the procalcitonin-protocol and control group. Because procalcitonin-guided antibiotic therapy has been shown to reduce the duration of treatment with antibiotics in critically ill patients without worsening the mortality rate or other outcomes, the implementation of a procalcitonin-guided antibiotic therapy should be considered for patients with proven or highly suspected bacterial infections in the intensive care unit. PMID:25898876
Neural Correlates in the Processing of Phoneme-Level Complexity in Vowel Production
ERIC Educational Resources Information Center
Park, Haeil; Iverson, Gregory K.; Park, Hae-Jeong
We investigated how articulatory complexity at the phoneme level is manifested neurobiologically in an overt production task. fMRI images were acquired from young Korean-speaking adults as they pronounced bisyllabic pseudowords in which we manipulated phonological complexity defined in terms of vowel duration and instability (viz., COMPLEX:ģ
Introspective duration estimation of reactive and proactive motor responses.
Gorea, Andrei; Mamassian, Pascal; Cardoso-Leite, Pedro
The metajudgment of motor responses refers to our ability to evaluate the accuracy of our own actions. Can humans metajudge the duration of their Reaction Times (RTs) to a light-flash and the accuracy of their reproduction of a reference time interval bounded by two light flashes (Anticipatory Response Time, ART)? A series of four distinct experiments shows that RT_Meta and ART_Metajudgments are possible but with accuracies about x2.4 and x3 poorer than the corresponding RT and ART ones. In order to reveal the origin of this drop in performance, we ask whether a visual feedback synchronous with subjects' key-presses could improve performance. We show that overall the presence of a visual feedback does not significantly improve metajudgment accuracy although such a trend is noticeable in ART_Meta. We then compare these performances with the passive perceptual estimation of the played back (Pb) RT and ART time intervals when bounded by two (RT_Pb) and three (ART_Pb) light flashes. We show that RT_Meta and RT_Pb accuracies are close to equal, but that ART_Meta is about x2 less accurate than ART_Pb which in turn is x1.5 less accurate than ART. The latter observation fails however to reach statistical significance hence not sustaining proposals that active time estimation is more reliable than passive one. The whole dataset is accounted for by a clock-type model where duration estimation performance is limited by four noise sources (visual, clock-count, motor and proprioceptive+efference copy) plus one proper to ART_Meta task. It is proposed that the latter reflects the impossibility for the time-counting system to use the same time origin more than once. PMID:20170893
Long-Duration Muscle Dedifferentiation during Limb Regeneration in Axolotls
Wu, Cheng-Han; Huang, Ting-Yu; Chen, Bo-Sung; Chiou, Ling-Ling; Lee, Hsuan-Shu
Although still debated, limb regeneration in salamanders is thought to depend on the dedifferentiation of remnant tissue occurring early after amputation and generating the progenitor cells that initiate regeneration. This dedifferentiation has been demonstrated previously by showing the fragmentation of muscle fibers into mononucleated cells and by revealing the contribution of mature muscle fibers to the regenerates by using lineage-tracing studies. Here, we provide additional evidence of dedifferentiation by showing that Pax7 (paired-box protein-7) transcripts are expressed at the ends of remnant muscle fibers in axolotls by using in situ hybridization and by demonstrating the presence of Pax7+ muscle-fiber nuclei in the early bud and mid-bud stages by means of immunohistochemical staining. During the course of regeneration, the remnant muscles did not progress; instead, muscle progenitors migrated out from the remnants and proliferated and differentiated in the new tissues at an early stage of differentiation. The regenerating muscles and remnant muscles were largely disconnected, and this left a gap between them until extremely late in the late stage of differentiation, at which point the new and old muscles connected together. Notably, Pax7 transcripts were detected in the regions of muscles that faced these gaps; thus, Pax7 expression might indicate dedifferentiation in the remnant-muscle ends and partial differentiation in the regenerating muscles. The roles of this long-duration dedifferentiation in the remnants remain unknown. However, the results presented here could support the hypothesis that long-duration muscle dedifferentiation facilitates the connection and fusion between the new and old muscles that are both in an immature state; this is because immature Pax7+ myoblasts readily fuse during developmental myogenesis. PMID:25671422
Developing a Habitat for Long Duration, Deep Space Missions
NASA Technical Reports Server (NTRS)
Rucker, Michelle A.; Thompson, Shelby
One possible next leap in human space exploration is a mission to a near Earth asteroid (NEA). In order to achieve such an ambitious goal, a space habitat will need to be designed to accommodate a crew of four for the 380-day round trip. The Human Spaceflight Architecture Team (HAT) developed a conceptual design for such a habitat. The team identified activities that would be performed inside a long-duration, deep space habitat, and the capabilities needed to support such a mission. A list of seven functional activities/capabilities was developed: individual and group crew care, spacecraft and mission operations, subsystem equipment, logistics and resupply, and contingency operations. The volume for each activity was determined using NASA STD-3001 and the companion Human Integration Design Handbook (HIDH). Although, the sum of these volumes produced an over-sized spacecraft, the team evaluated activity frequency and duration to identify functions that could share a common volume without conflict, reducing the total volume by 24%. After adding 10% for growth, the resulting functional pressurized volume was calculated to be 268 m3 distributed over the functions. The work was validated through comparison with the International Space Station (ISS), Bigelow Aerospace s proposed habitat module, and NASA s Trans-Hab concepts. In the end, the team developed an internal layout that (a) minimized the transit time between related crew stations, (b) accommodated expected levels of activity at each station, (c) isolated stations when necessary for health, safety, performance, and privacy, and (d) provided a safe, efficient, and comfortable work and living environment.
The Iceland Basin excursion: Age, duration, and excursion field geometry
NASA Astrophysics Data System (ADS)
Channell, J. E. T.
Iceland Basin geomagnetic excursion coincided with the marine isotope stage (MIS) 6/7 boundary. The age and duration of the excursion, at seven North Atlantic sites with sufficient isotope data, are estimated by matching marine isotope stage (MIS) 7a-7c to a calibrated template. Two criteria for defining the excursion, virtual geomagnetic pole (VGP) latitudes <0░ and <40░N, yield excursion durations of 1-4 and 2-5 kyr, respectively. The midpoints of the excursion are in the 189-192 ka range, with a mean of ś190.2 ka. Although component magnetization directions are generally well defined, rapid changes in field direction during a time of low field intensity are not adequately recorded. During the excursion, VGPs transit southward over Africa and the South Atlantic, reach high southern latitudes at the culmination of the excursion, with partial recovery in relative paleointensity (RPI), and then track northward through the western Pacific. The high southern latitude VGPs, and the recovery in RPI, imply that the Earth's main axial dipole reversed polarity during the excursion, if only for ś1 kyr; implying that excursions can be manifested globally and are important in millennial-scale stratigraphy. VGP clustering in the South Atlantic and NW Pacific roughly coincide with maxima in the vertical-downward component of the modern nondipole (ND) field determined at the Earth's surface, which implies that the ND field became dominant as the geocentric dipole field weakened during the excursion, and also that the ND field configuration is long-lived on multimillennial timescales.
Does Treatment Duration Affect Outcome After Radiotherapy for Prostate Cancer?
D'Ambrosio, David J. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Li Tianyu [Department of Biostatistics, Fox Chase Cancer Center, Philadelphia, PA (United States); Horwitz, Eric M. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Chen, David Y.T. [Department of Surgical Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Pollack, Alan [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Buyyounouski, Mark K. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States)], E-mail: email@example.com
Purpose: The protraction of external beam radiotherapy (RT) time is detrimental in several disease sites. In prostate cancer, the overall treatment time can be considerable, as can the potential for treatment breaks. We evaluated the effect of elapsed treatment time on outcome after RT for prostate cancer. Methods and Materials: Between April 1989 and November 2004, 1,796 men with prostate cancer were treated with RT alone. The nontreatment day ratio (NTDR) was defined as the number of nontreatment days divided by the total elapsed days of RT. This ratio was used to account for the relationship between treatment duration and total RT dose. Men were stratified into low risk (n = 789), intermediate risk (n = 798), and high risk (n = 209) using a single-factor model. Results: The 10-year freedom from biochemical failure (FFBF) rate was 68% for a NTDR <33% vs. 58% for NTDR {>=}33% (p = 0.02; BF was defined as a prostate-specific antigen nadir + 2 ng/mL). In the low-risk group, the 10-year FFBF rate was 82% for NTDR <33% vs. 57% for NTDR {>=}33% (p = 0.0019). The NTDR was independently predictive for FFBF (p = 0.03), in addition to T stage (p = 0.005) and initial prostate-specific antigen level (p < 0.0001) on multivariate analysis, including Gleason score and radiation dose. The NTDR was not a significant predictor of FFBF when examined in the intermediate-risk group, high-risk group, or all risk groups combined. Conclusions: A proportionally longer treatment duration was identified as an adverse factor in low-risk patients. Treatment breaks resulting in a NTDR of {>=}33% (e.g., four or more breaks during a 40-fraction treatment, 5 d/wk) should be avoided.
Factors Impacting Habitable Volume Requirements for Long Duration Missions
NASA Technical Reports Server (NTRS)
Simon, Matthew; Neubek, Deborah; Whitmire, Alexandria
One possible next leap in human space exploration for the National Aeronautics and Space Administration (NASA) is a mission to a near Earth asteroid (NEA). In order to achieve such an ambitious goal, a space habitat will need to accommodate a crew of four for the 380-day round trip. The Human Spaceflight Architecture Team (HAT) developed a conceptual design for such a habitat. The team identified activities that would be performed inside a long-duration, deep space habitat, and the capabilities needed to support such a mission. A list of seven functional activities/capabilities was developed: individual and group crew care, spacecraft and mission operations, subsystem equipment, logistics and resupply, and contingency operations. The volume for each activity was determined using NASA STD-3001 and the companion Human Integration Design Handbook (HIDH). Although, the sum of these volumes produced an over-sized spacecraft, the team evaluated activity frequency and duration to identify functions that could share a common volume without conflict, reducing the total volume by 24%. After adding 10% for growth, the resulting functional pressurized volume was calculated to be a minimum of 268 m3 (9,464 ft3) distributed over the functions. The work was validated through comparison to Mir, Skylab, the International Space Station (ISS), Bigelow Aerospace s proposed habitat module, and NASA s Trans-Hab concept. Using HIDH guidelines, the team developed an internal layout that (a) minimized the transit time between related crew stations, (b) accommodated expected levels of activity at each station, (c) isolated stations when necessary for health, safety, performance, and privacy, and (d) provided a safe, efficient, and comfortable work and living environment.
Active shielding for long duration interplanetary manned missions
NASA Astrophysics Data System (ADS)
Spillantini, Piero
For long duration interplanetary manned missions the protection of astronauts from cosmic radiation is an unavoidable problem that has been considered by many space agencies. In Europe, during 2002-2004, the European Space Agency supported two research programs on this thematic: one was the constitution of a dedicated study group (on the thematic 'Shielding from cosmic radiation for interplanetary missions: active and passive methods') in the framework of the 'life and physical sciences' report, and the other an industrial study concerning the 'radiation exposure and mission strategies for interplanetary manned missions to Moon and Mars'. Both programs concluded that, outside the protection of the magnetosphere and in the presence of the most intense and energetic solar events, the protection cannot rely solely on the mechanical structures of the spacecraft, but a temporary shelter must be provided. Because of the limited mass budget, the shelter should be based on the use of superconducting magnetic systems. For long duration missions the astronauts must be protected from the much more energetic galactic cosmic rays during the whole mission period. This requires the protection of a large habitat where they could live and work, and not the temporary protection of a small volume shelter. With passive absorbers unable to play any significant role, the use of active shielding is mandatory. The possibilities offered by superconducting magnets are discussed, and recommendations are made about the needed R&D. The technical developments that have occurred in the meanwhile and the evolving panorama of possible near future interplanetary missions, require revising the pioneering studies of the last decades and the adoption of a strategy that considers long lasting human permanence in 'deep' space, moreover not only for a relatively small number of dedicated astronauts but also for citizens conducting there 'normal' activities.
[Duration of breast-feeding in the Dominican Republic].
Bautista, L E
The present study reanalyzed data from the Dominican Republic National Health Survey, conducted in 1991, in order to identify the socioeconomic characteristics and the factors related to medical care, the pregnancy, and the child which influenced the total duration of breast-feeding (TDBF). A representative sample of 1984 mother-infant pairs was studied. Of the children of each mother, only the last one who was breast-fed and was less than three years old at the time of the survey was included. Data on TDBF and the factors studied were collected by interviewing the mothers. The risk of having been weaned at various ages was calculated by means of a life table, and the independent effect of each variable of interest was estimated using Cox's regression model. The median TDBF was 7 months and the relative weaning rate (RWR) was higher among weaned children (RWR = 8.56; 95%CI: 4.25-17.20), those whose mothers had a university education (RWR = 1.48; 95%CI: 1.24-1.77), those who began to suckle late (RWR = 1.25; 95%CI: 1.11-1.40), those who were born in public institutions (RWR = 1.62; 95%CI: 1.24-2.11) and private institutions (RWR = 2.19; 95%CI: 1.65-2.91), and those born to first-time mothers of a low socioeconomic level (RWR = 1.80; 95%CI: 1.45-2.24). Among the strategies of programs to promote breast-feeding, the importance of delayed weaning should be underscored, since this factor has the greatest influence on duration of breast-feeding. PMID:8782496
Sleep duration and all-cause mortality: a critical review of measurement and associations
Kurina, Lianne M.; McClintock, Martha K.; Chen, Jen-Hao; Waite, Linda J.; Thisted, Ronald A.; Lauderdale, Diane S.
Purpose Variation in sleep duration has been linked with mortality risk. The purpose of this review is to provide an updated evaluation of the literature on sleep duration and mortality, including a critical examination of sleep duration measurement and an examination of correlates of self-reported sleep duration. Methods We did a systematic search of studies reporting associations between sleep duration and all-cause mortality and extracted the sleep duration measure and the measure(s) of association. Results We identified 42 prospective studies of sleep duration and mortality drawing on 35 distinct study populations across the globe. Unlike previous reviews, we find that the published literature does not support a consistent finding of an association between self-reported sleep duration and mortality. Most studies have employed survey measures of sleep duration, which are not highly correlated with estimates based on physiologic measures. Conclusions Despite a large body of literature, it is premature to conclude, as previous reviews have, that a robust, U-shaped association between sleep duration and mortality risk exists across populations. Careful attention must be paid to measurement, response bias, confounding, and reverse causation in the interpretation of associations between sleep duration and mortality. PMID:23622956
Marked Exacerbation of Orthostatic Intolerance After Long vs. Short-Duration Spaceflight in Veteran Astronauts
NASA Technical Reports Server (NTRS)
Fritsch-Yelle, Janice M.; Reyes, Carlos; Perez, Sondra A.; Goldberger, Ary L.; Ziegler, Michael G.; Paloski, William H. (Technical Monitor)
The incidence of postflight orthostatic intolerance following short-duration spaceflight is about 20%. However, the incidence following long-duration spaceflight is unknown. We performed tilt tests on six astronauts before and after their long-duration (129 - 190 days) spaceflights and compared these data to those obtained during stand tests before and after their previous short-duration missions and also to tilt test data from 20 different short-duration (8 - 16 days) flight astronauts. Five of these six became presyncopal during tilt testing after long-duration flights: only one had become presyncopal during stand testing after short-duration flights. Five of the twenty astronauts who flew on other short-duration flights, became presyncopal during upright tilt on landing day. Long-duration presyncopal subjects had lower stroke volumes, lower cardiac outputs and higher peripheral vascular resistance than short-duration presyncopal subjects, but their heart rate responses were not different. One subject had subnormal norepinephrine release with upright posture after a long but not short flight. Plasma volume losses were not greater after long flights. Long-duration spaceflight markedly increases orthostatic intolerance, probably related to altered autonomic function.
Prior time uncertainty reduction of foreperiod duration in schizophrenia and old age.
Mo, S S; Kersey, R
Four groups of college students, alcoholics, schizophrenics, and old age Ss judged stimulus durations of .50 and .55 seconds. The stimulus was preceded by a sound that functioned as the warning signal. The foreperiod duration, that is, the interval between the onsets of the warning signal and the stimulus, was variable and was either 1,3, or 5 seconds. There was no group difference with respect to the effect of foreperiod variability. Estimation of stimulus duration was a monotonically increasing function of foreperiod duration. However, when pitch of the sound was correlated with the corresponding foreperiod duration, this monotonic relation between foreperiod duration and estimation of stimulus duration was eliminated for schizophrenics, but not for nonschizophrenics. Although schizophrenics were not distinguishable from nonschizophrenics in terms of the effect of foreperiod variability, receptivity to prior information associated with time uncertainty reduction was shown to be unique for schizophrenia. PMID:833327
The aftereffect of perceived duration is contingent on auditory frequency but not visual orientation
Li, Baolin; Yuan, Xiangyong; Huang, Xiting
Recent sensory history plays a critical role in duration perception. It has been established that after adapting to a particular duration, the test durations within a certain range appear to be distorted. To explore whether the aftereffect of perceived duration can be constrained by sensory modality and stimulus feature within a modality, the current study applied the technique of simultaneous sensory adaptation, by which observers were able to simultaneously adapt to two durations defined by two different stimuli. Using both simple visual and auditory stimuli, we found that the aftereffect of perceived duration is modality specific and contingent on auditory frequency but not visual orientation of the stimulus. These results demonstrate that there are independent timers responsible for the aftereffects of perceived duration in each sensory modality. Furthermore, the timer for the auditory modality may be located at a relatively earlier stage of sensory processing than the timer for the visual modality. PMID:26054927
The aftereffect of perceived duration is contingent on auditory frequency but not visual orientation.
Li, Baolin; Yuan, Xiangyong; Huang, Xiting
Recent sensory history plays a critical role in duration perception. It has been established that after adapting to a particular duration, the test durations within a certain range appear to be distorted. To explore whether the aftereffect of perceived duration can be constrained by sensory modality and stimulus feature within a modality, the current study applied the technique of simultaneous sensory adaptation, by which observers were able to simultaneously adapt to two durations defined by two different stimuli. Using both simple visual and auditory stimuli, we found that the aftereffect of perceived duration is modality specific and contingent on auditory frequency but not visual orientation of the stimulus. These results demonstrate that there are independent timers responsible for the aftereffects of perceived duration in each sensory modality. Furthermore, the timer for the auditory modality may be located at a relatively earlier stage of sensory processing than the timer for the visual modality. PMID:26054927
The index æTreatment Duration ControlÆ for enabling randomized controlled trials with variation in duration of treatment of chronic pain patients
Background Treatment duration varies with the type of therapy and a patientÆs recovery speed. Including such a variation in randomized controlled trials (RCTs) enables comparison of the actual therapeutic potential of different therapies in clinical care. An index, Treatment Duration Control (TDC) of outcome scores was developed to help decide when to end treatment and also to determine treatment outcome by a blinded assessor. In contrast to traditional Routine Outcome Monitoring which considers raw score changes, TDC uses relative change. Methods Our theory shows that if a patient with the largest baseline scores in a sample requires a relative decrease by treatment factor T to reach a zone of low score values (functional status), any patient with smaller baselines will attain functional status with T. Furthermore, the end score values are proportional to the baseline. These characteristics concur with findings from the literature that a patientÆs assessment of æmuch improvedÆ following treatment (related to attaining functional status) is associated with a particular relative decrease in pain intensity yielding a final pain intensity that is proportional to the baseline. Regarding the TDC-procedure: those patientÆs scores that were related to pronounced signs and symptoms, were selected for adaptive testing (reference scores). A Contrast-value was determined for each reference score between its reference level and a subsequent level, and averaging all Contrast-values yielded TDC. A cut-off point related to factor T for attaining functional status, was the TDC-criterion to end a patientÆs treatment as being successful. The use of TDC has been illustrated in RCT data from 118 chronic pain patients with myogenous Temporomandibular Disorders, and the TDC-criterion was validated. Results The TDC-criterion of successful/unsuccessful treatment approximated the cut-off separating two patient subgroups in a bimodal post-treatment distribution of TDC-values. Pain intensity decreased to residual levels and Health-Related Quality of Life (HRQoL) increased to normal levels, following successful treatment according to TDC. The post-treatment TDC-values were independent from the baseline values of pain intensity or HRQoL, and thus independent from the patientÆs baseline severity of myogenous Temporomandibular Disorders. Conclusions TDC enables RCTs that have a variable therapy- and patient-specific duration. PMID:24112821
Sequence Complexity Effects on Speech Production in Healthy Speakers and Speakers with Hypokinetic or Ataxic Dysarthria
Reilly, Kevin J.; Spencer, Kristie A.
The present study investigated the effects of sequence complexity, defined in terms of phonemic similarity and phonotoactic probability, on the timing and accuracy of serial ordering for speech production in healthy speakers and speakers with either hypokinetic or ataxic dysarthria. Sequences were comprised of strings of consonant-vowel (CV) syllables with each syllable containing the same vowel, /a/, paired with a different consonant. High complexity sequences contained phonemically similar consonants, and sounds and syllables that had low phonotactic probabilities; low complexity sequences contained phonemically dissimilar consonants and high probability sounds and syllables. Sequence complexity effects were evaluated by analyzing speech error rates and within-syllable vowel and pause durations. This analysis revealed that speech error rates were significantly higher and speech duration measures were significantly longer during production of high complexity sequences than during production of low complexity sequences. Although speakers with dysarthria produced longer overall speech durations than healthy speakers, the effects of sequence complexity on error rates and speech durations were comparable across all groups. These findings indicate that the duration and accuracy of processes for selecting items in a speech sequence is influenced by their phonemic similarity and/or phonotactic probability. Moreover, this robust complexity effect is present even in speakers with damage to subcortical circuits involved in serial control for speech. PMID:24146997
The BESS-Polar II Long Duration Flight above Antarctica
NASA Astrophysics Data System (ADS)
Sasaki, Makoto
The Balloon-borne Experiment with a Superconducting Spectrometer, BESS, has been developed to study elementary particle phenomena in the early universe through measurements of low energy antiprotons to investigate their origin and through a search for antihelium. The BESS collaboration carried out nine northern latitude flights between 1993 and 2002. BESS- Polar is an advanced program of the BESS collaboration to study these topics with much greater precision using long duration flights above Antarctica. The BESS-Polar spectrometer was successfully developed to accumulate much larger numbers of events during long duration flights around the South Pole. Approximately a factor of four reductions in the amount of material in the particle beam enables measurement of much lower energy antiprotons down to 100 MeV (at top of atmosphere). The first BESS-Polar flight (BESS-Polar I) of 8.5 days was carried out above Antarctica in December 2004, recording 900 million cosmic-ray events. The second BESS-Polar flight (BESS-Polar II) was successfully carried out in the austral summer season of 2007-2008. Based on experience with BESS-Polar I, the spectrometer was improved in performance and achieved long term stability during the flight. A newly constructed magnet with a larger liquid He capacity and improved thermal insulation and an upgraded data storage system with larger capacity of hard disk drives (HDDs) enabled longer observation time. BESS-Polar II was launched on December 22, 2007 from Williams Field, McMurdo Station, in Antarctica. The spectrometer worked properly and observed cosmic rays for about 24.5 days at float altitude, recording 4.6 billion events on the HDDs until the limit of the magnet operation was reached on January 16, 2008. The flight was terminated and the spectrometer was safely landed on the West Antarctic ice sheet ( 1000 km from the South Pole) on January 21, 2008. Here, the BESS-Polar instrument is discussed, highlighting improvements made for BESS-Polar II, and overviews of the flight and performance are reported.
NEXT Long-Duration Test Neutralizer Performance and Erosion Characteristics
NASA Technical Reports Server (NTRS)
Herman, Daniel A.; Soulas, George C.; Patterson, Michael J.
The NASA's Evolutionary Xenon Thruster (NEXT) program is developing the next-generation ion propulsion system with significant enhancements beyond the state-of-the-art to provide future NASA science missions with enhanced capabilities at a low total development cost. A Long-Duration Test (LDT) was initiated in June 2005, to verify the NEXT propellant throughput capability to a qualification-level of 450 kg, 1.5 times the anticipated throughput requirement of 300 kg per thruster based on mission analyses. As of September 2, 2009, the thruster has accumulated 24,400 hr of operation with extensive durations at the following input powers: 6.9, 4.7, 1.1, and 0.5 kW. The thruster has processed 434 kg of xenon, surpassing the NASA Solar Technology Application Readiness (NSTAR) program thruster propellant throughput demonstrated during the extended life testing of the Deep Space 1 flight spare ion thruster and approaching the NEXT development qualification throughput goal of 450 kg. The NEXT LDT has demonstrated a total impulse of 16.1 10(exp 6zzz0 N s; the highest total impulse ever demonstrated by an ion thruster. A reduction in neutralizer flow margin has been the only appreciable source of thruster performance degradation. The behavior of the neutralizer is not easily predicted due to both erosion and deposition observed in previous wear tests. Spot-to-plume mode transition flow data and in-situ erosion results for the LDT neutralizer are discussed. This loss of flow margin has been addressed through a combination of a design change in the prototype-model neutralizer to increase flow margin at low emission current and to update the NEXT throttle table to ensure adequate flow margin as a function of propellant throughput processed. The new throttle table will be used for future LDT operations. The performance of the NEXT LDT neutralizer is consistent with that observed for long-life hollow cathodes. The neutralizer life-limiting failure modes are progressing as expected and the neutralizer data indicate none of the neutralizer failures are imminent.
Palaeolithic extinctions and the Taurid Complex
W. M. Napier
Intersection with the debris of a large (50-100 km) short-period comet during\\u000athe Upper Palaeolithic provides a satisfactory explanation for the catastrophe\\u000aof celestial origin which has been postulated to have occurred around 12900 BP,\\u000aand which presaged a return to ice age conditions of duration ~1300 years. The\\u000aTaurid Complex appears to be the debris of this erstwhile comet;
Palaeolithic extinctions and the Taurid Complex
W. M. Napier
Intersection with the debris of a large (50-100km) short-period comet during the Upper Palaeolithic provides a satisfactory explanation for the catastrophe of celestial origin which has been postulated to have occurred around 12900 BP, and which presaged a return to ice age conditions of duration ~1300yr. The Taurid Complex appears to be the debris of this erstwhile comet; it includes
Lessons Learned from Biosphere 2: When Viewed as a Ground Simulation/Analogue for Long Duration Human Space Exploration and Settlement
NASA Astrophysics Data System (ADS)
MacCallum, T.; Poynter, J.; Bearden, D.
A human mission to Mars, or a base on the Moon or Mars, is a longer and more complex mission than any space endeavor undertaken to date. Ground simulations provide a relevant, analogous environment for testing technologies and learning how to manage complex, long duration missions, while addressing inherent mission risks. Multiphase human missions and settlements that may preclude a rapid return to Earth, require high fidelity, end-to-end, at least full mission duration tests in order to evaluate a system's ability to sustain the crew for the entire mission and return the crew safely to Earth. Moreover, abort scenarios are essentially precluded in many mission scenarios, though certain risks may only become evident late in the mission. Aging and compounding effects cannot be simulated through accelerated tests for all aspects of the mission. Until such high fidelity long duration simulations are available, and in order to help prepare those simulations and mission designs, it is important to extract as many lessons as possible from analogous environments. Possibly the best analogue for a long duration space mission is the two year mission of Biosphere 2. Biosphere 2 is a three-acre materially closed ecological system that supported eight crewmembers with food, air and water in a sunlight driven bioregenerative system for two years. It was designed for research applicable to environmental management on Earth and the development of human life support for space. A brief overview of the two-year Biosphere 2 mission is presented, followed by select data and lessons learned that are applicable to the design and operation of a long duration human space mission, settlement or test bed. These lessons include technical, programmatic, and psychological issues
Anticipatory Postural Activity During Long-Duration Space Flight
NASA Technical Reports Server (NTRS)
Layne, C. S.; Mulavara, A. P.; McDonald, P. V.; Pruett, C. J.; Koslovskaya, B.; Bloomberg, J. J.
Somatosensory input has been used to modify motor output in many contexts. During space flight, the use of the lower limb musculature is much less than during activities in 1g. Consequently the neuromuscular activity of the legs is also reduced during space flight. This decrease in muscle activity contributes to muscle atrophy. Furthermore, adaptations to weightlessness contribute to posture and locomotion problems upon the return to Earth. Providing techniques to counter the negative effects of weightlessness on the neuromuscular system is an important goal, particularly during a long-duration mission. Previous work by our group has shown that lower limb neuromuscular activation that normally precedes arm movements in 1g is absent or greatly reduced during similar movements made while freefloating. However, preliminary evidence indicates that applying pressure to the feet results in enhanced neuromuscular activation during rapid arm movements performed while freefloating. This finding suggests that sensory input can be used to "drive" the motor system to increase neuromuscular functioning throughout a mission. The purpose of this investigation was to quantify the increase in neuromuscular activation resulting from the application of pressure to the feet.
Preliminary total dose measurements on LDEF. [long duration exposure facility
NASA Technical Reports Server (NTRS)
Reitz, G.
After spending nearly six years in Earth's orbit twenty stacks consisting of radiation detectors and biological objects are now back on Earth. These Free Flyer Biostack experiments are part of the Long Duration Exposure Facility (LDEF). The major objective of the experiments are to investigate the biological effectiveness of single heavy ions of the cosmic radiation in various biological systems and to provide information about the spectral composition of the radiation field and the total dose received in the LDEF orbit. The preliminary analysis of the thermoluminescence dosimeters (TLD) yields maximum absorbed dose rates of 2.24 mGy day(exp -1) behind 0.7 g cm(exp -2) shielding and 1.17 mGy day(exp -1) behind 12 g cm(exp -2) shielding. A thermal neutron fluence of 1.7 n cm(exp -2)s(exp -1) is determined from the differences in absorbed dose for different isotopic mixtures of lithium. The results of this experiment on LDEF are especially valuable since LDEF stayed for almost six years in the prospected orbit of the Space Station Freedom.
Estimating the duration of sexual behavior: a laboratory analog study.
Levitt, E E
Estimate of male orgasm latency, a common parameter of the sex history, is hypothetically subject to retrospective distortion. This investigation attempted to assess the degree and direction of the distortion using a laboratory analog procedure. Groups of sophomore medical students were shown a movie depicting a couple engaging in continuous foreplay and coitus. About half were asked to estimate the length of the foreplay and coitus periods in minutes. The other half were required to judge whether time periods were average, below average, or above average in duration for people of their own age. Subjects tended to overestimate the length of the coitus period in the film, but not the foreplay period. Females tended to estimate both periods as significantly longer than males. Nearly half of the group judged the foreplay period to be average, and over 60% judged the coital period to be average. Less than 23% thought that the coital period was below average. Married subjects tended to regard both time periods as above average, compared to single subjects. A possible inference from this investigation is that the mean young adult male orgasm latency is probably in the range of 2-3 minutes. PMID:6639328
Duration and Extent of the Great Auroral Storm of 1859
NASA Technical Reports Server (NTRS)
Green, James L.; Boardsen, Scott
The great geomagnetic storm of August 28 through September 3,1859 is, arguably, the greatest and most famous space weather event in the last two hundred years. For the first time observations showed that the sun and aurora were connected and that auroras generated strong ionospheric currents. A significant portion of the world's 200,000 km of telegraph lines were adversely affected, many of which were unusable for 8 hours or more which had a real economic impact. In addition to published scientific measurements, newspapers, ship logs, and other records of that era provide an untapped wealth of first hand observations giving time and location along with reports of the auroral forms and colors. At its height, the aurora was described as a blood or deep crimson red that was so bright that one "could read a newspaper by." At its peak, the Type A red aurora lasted for several hours and was observed to reach extremely low geomagnetic latitudes on August 28-29 (-25") and on September 2-3 (-18"). Auroral forms of all types and colors were observed below 50" latitude for -24 hours on August 28-29 and -42 hours on September 2-3. From a large database of ground-based observations the extent of the aurora in corrected geomagnetic coordinates is presented over the duration of the storm event.
Long-duration animal tracking in difficult lighting conditions
Stern, Ulrich; Zhu, Edward Y.; He, Ruo; Yang, Chung-Hui
High-throughput analysis of animal behavior requires software to analyze videos. Such software typically depends on the experimentsÆ being performed in good lighting conditions, but this ideal is difficult or impossible to achieve for certain classes of experiments. Here, we describe techniques that allow long-duration positional tracking in difficult lighting conditions with strong shadows or recurring ōonö/ōoffö changes in lighting. The latter condition will likely become increasingly common, e.g., for Drosophila due to the advent of red-shifted channelrhodopsins. The techniques enabled tracking with good accuracy in three types of experiments with difficult lighting conditions in our lab. Our technique handling shadows relies on single-animal tracking and on shadowsÆ and fliesÆ being accurately distinguishable by distance to the center of the arena (or a similar geometric rule); the other techniques should be broadly applicable. We implemented the techniques as extensions of the widely-used tracking software Ctrax; however, they are relatively simple, not specific to Drosophila, and could be added to other trackers as well. PMID:26130571
Long Duration Exposure Facility experiment M0003 deintegration observation database
NASA Technical Reports Server (NTRS)
Gyetvay, S. R.; Kan, H. K. A.; Coggi, J. M.; Meshishnek, M. J.
The four trays of the M0003 materials experiment on LDEF contained 1274 samples from 19 subexperiments. The complete sample complement represented a broad range of materials, including thin film optical coatings, paints, polymer sheets and tapes, adhesives, and composites, for use in various spacecraft applications including thermal control, structures, optics, and solar power. Since some subexperiments included duplicate samples exposed on the leading and trailing edge trays, for 9 week, 19 week, 40 week, and 68 month durations on both the leading and trailing edges, comparisons provided a valuable time history of degradation. During the deintegration of the subexperiments from the M0003 trays, each sample was examined using bright field, dark field, and Normarski light microscopy techniques. Over 3,000 color macrographs and photomicrographs were made of the condition of M0003 trays and the individual samples. Records of the condition of the samples, photographic records, and all available references of publications on postflight analyses on each sample were collected in a database. The photographs provide a visual comparison of the response of materials common to various subexperiments in different LDEF environments. Aerospace Corporation is distributing the database records and photographs and written records on materials of interest from the database is given in this presentation.
Long-duration animal tracking in difficult lighting conditions.
Stern, Ulrich; Zhu, Edward Y; He, Ruo; Yang, Chung-Hui
High-throughput analysis of animal behavior requires software to analyze videos. Such software typically depends on the experiments' being performed in good lighting conditions, but this ideal is difficult or impossible to achieve for certain classes of experiments. Here, we describe techniques that allow long-duration positional tracking in difficult lighting conditions with strong shadows or recurring "on"/"off" changes in lighting. The latter condition will likely become increasingly common, e.g., for Drosophila due to the advent of red-shifted channelrhodopsins. The techniques enabled tracking with good accuracy in three types of experiments with difficult lighting conditions in our lab. Our technique handling shadows relies on single-animal tracking and on shadows' and flies' being accurately distinguishable by distance to the center of the arena (or a similar geometric rule); the other techniques should be broadly applicable. We implemented the techniques as extensions of the widely-used tracking software Ctrax; however, they are relatively simple, not specific to Drosophila, and could be added to other trackers as well. PMID:26130571