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1

Detection of low amplitude fetal QRS complexes.  

PubMed

The significance of the most important operations performed by the noninvasive systems for fetal heart rate determination is investigated. The method of template subtraction for maternal ECG suppression is compared to the method based on independent component analysis. The QRS detector based on the classical slope-responsive preprocessing competes with the one that employs normalized matched filtering for QRS enhancement. A small database containing the four-channel abdominal ECG signals with the marked positions of the fetal QRS complexes is prepared to enable the investigations. The performed experiments show the factors that have the greatest impact on the results of the fetal QRS detection, and an effective approach to cope the problem is proposed. PMID:19163781

Kotas, Marian; Jezewski, Janusz; Kupka, Tomasz; Horoba, Krzysztof

2008-01-01

2

Wide QRS complex tachycardia: ECG differential diagnosis  

Microsoft Academic Search

Wide QRS complex tachycardias (WCT) present significant diagnostic and therapeutic challenges to the emergency physician. WCT may represent a supraventricular tachycardia with aberrant ventricular conduction; alternatively, such a rhythm presentation may be caused by ventricular tachycardia. Other clinical syndromes may also demonstrate WCT, such as tricyclic antidepressant toxicity and hyperkalemia. Patient age and history may assist in rhythm diagnosis, especially

William J Brady; Jeff Skiles

1999-01-01

3

On-Line QRS Complex Detection Using Wavelet Filtering.  

National Technical Information Service (NTIS)

This paper presents a new QRS complex detection algorithm that can be applied in various on-line FCC processing systems The algorithm is performed in two steps: first a wavelet transform filtering is applied to the signal, then QRS complex localization is...

L. Szilagyi, Z. Benyo, S. M. Szilagyi, L. Nagy

2001-01-01

4

Detection of fetal QRS-complexes by external methods.  

PubMed

A new method is presented for detection of the QRS complexes and the fetal heart rate from the fetal magnetocardiogram and from the fetal electrocardiogram. In the method, the amplitude, the polarity and the shape of the QRS complex are tested. By using the described equipment it is possible to detect all consecutive heart beat intervals from a fetal electrocardiogram with less than 1% error in timing. When an external fetal electrocardiogram was used for testing, generally slightly over 10% of the QRS complexes were lost since they were simultaneous with the maternal complexes. In addition, complexes were also lost due to noise. PMID:1217840

Ahopelto, J; Hukkinen, K; Katila, T E; Laine, H; Kariniemi, V

1975-01-01

5

On the variability of QRS time-duration in magnetocardiographic recordings.  

PubMed

High resolution electrocardiography (HRECG) recordings have already shown an increased beat-to-beat microvariability of the QRS duration of the terminal QRS in patients with a history of ventricular tachycardia (VT). The purpose of this study is to detect QRS-duration microvariability with magnetocardiographic (MCG) recordings in normals, patients with coronary heart disease (CHD), patients with a history of myocardial infarction (MI), and VT patients. QRS microvariability is calculated as the variance of time-shifts of single beats respectively to the average of all beats. The average over all channels of the MCG is performed. QRS microvariability was evaluated from 55-channel MCG in 15 normal persons, in 12 patients with CHD, in 13 patients with MI, and in 10 patients with VT. We found a significantly higher microvariability in patients with MI compared to normals. The highest microvariability was found in VT patients. PMID:12775457

Schless, B G; Müller, H-P; Pasquarelli, A; Erné, S N; Hombach, V

2003-01-01

6

Adaptive Threshold for QRS Complex Detection Based on Wavelet Transform.  

PubMed

This paper presents a novel approach, adaptive threshold algorithm, for QRS complex detection. It is based on two-to-four scales in COIFLET wavelet transform. Two initial thresholds are defined as up-limited-threshold (ULT) and down-limited-threshold (DLT) at the beginning of the detection. The system then automatically adjusts the values of the threshold to achieve optimal QRS detection. Simulation work shows that adaptive threshold algorithm can give more accurate results than fixed algorithms. By means of weights of missing and fault detection, ULT and DLT are adapted to get more accurate detecting results. More important for this algorithm is that it can increase the recognition efficiency greatly. PMID:17281961

Xu, Xiaomin; Liu, Ying

2005-01-01

7

A novel feature extracting method of QRS complex classification for mobile ECG signals  

NASA Astrophysics Data System (ADS)

The conventional classification parameters of QRS complex suffer from larger activity rang of patients and lower signal to noise ratio in mobile cardiac telemonitoring system and can not meet the identification needs of ECG signal. Based on individual sinus heart rhythm template built with mobile ECG signals in time window, we present semblance index to extract the classification features of QRS complex precisely and expeditiously. Relative approximation r2 and absolute error r3 are used as estimating parameters of semblance between testing QRS complex and template. The evaluate parameters corresponding to QRS width and types are demonstrated to choose the proper index. The results show that 99.99 percent of the QRS complex for sinus and superventricular ECG signals can be distinguished through r2 but its average accurate ratio is only 46.16%. More than 97.84 percent of QRS complexes are identified using r3 but its accurate ratio to the sinus and superventricular is not better than r2. By the feature parameter of width, only 42.65 percent of QRS complexes are classified correctly, but its accurate ratio to the ventricular is superior to r2. To combine the respective superiority of three parameters, a nonlinear weighing computation of QRS width, r2 and r3 is introduced and the total classification accuracy up to 99.48% by combing indexes.

Zhu, Lingyun; Wang, Dong; Huang, Xianying; Wang, Yue

2007-12-01

8

Impact of heart rate on mechanical dyssynchrony and left ventricular contractility in patients with heart failure and normal QRS duration  

Microsoft Academic Search

Aims: The quantification of mechanical dyssynchrony has important diagnostic value and may help to determine optimal therapy in heart failure (HF). We hypothesized that mechanical dyssynchrony may be augmented at increased heart rates in patients with HF and normal QRS duration. Methods and results: From online segmental conductance catheter signals, we derived indices to quantify temporal and spatial aspects of

Tairo Kurita; Katsuya Onishi; Kaoru Dohi; Masaki Tanabe; Naoki Fujimoto; Takashi Tanigawa; Morimichi Setsuda; Naoki Isaka; Tsutomu Nobori; Masaaki Ito

2007-01-01

9

Real Time Matched Filter Detection of the Qrs Complex by Replica Correlation.  

National Technical Information Service (NTIS)

The report describes an approach to optimum detection of each cardiac cycle from noisy electrocardiograms. A filter matched to the QRS complex of the electrocardiogram is proposed to achieve the results. It is demonstrated analytically that such a filter ...

A. J. Welch, C. A. Braun, F. B. Vogt, F. X. Bostick, P. C. Richardson

1970-01-01

10

Spatial magnitude of the normal QRS-complex in the electrocardiogram of rabbits. Velocity and acceleration of the spatial magnitude.  

PubMed

The article describes the curves of the spatial magnitude (SM) of the normal QRS-complex in 52 rabbits, as well as of the velocity and acceleration of SM as a function of time. The X-, Y- and Z-recordings after McFee and Parungao are subjected to analogue-to-digital conversion and computer-calculation. The SM-curve consists of two and less frequently of three peaks, the third peak having the greatest amplitude and the first peak--the smallest. The three peaks are discovered at 16, 41 and 64 per cent, respectively, of the duration of the QRS-complex. The results are discussed in relation to data about other mammals and humans. The characteristic points in the curves of the recorded parameters are compared. PMID:3832790

Lolov, R

1985-01-01

11

Methodology for automated detection of fragmentation in QRS complex of Standard 12-lead ECG.  

PubMed

Fragmented QRS (f-QRS) has been found to have higher sensitivity and/or specificity values for several diseases including remote and acute myocardial infarction, cardiac sarcoidosis etc, compared to other conventional bio-markers viz. Q-wave, ST-elevation etc. Several of these diseases do not have a reliable bio-marker and hence, patients suffering from them have to undergo expensive and sometimes invasive tests for diagnosis viz. myocardial biopsy, cardiac catheterization etc. This paper proposes automation of fragmentation detection which will lead to a more reliable diagnosis and therapy reducing human error, time consumption and thereby alleviating the need of enormous training required for detection of fragmentation. In this paper, we propose a novel approach to detect the discontinuities present in QRS complex of standard 12-lead ECG, known as fragmented QRS, using Discrete Wavelet transform (DWT) targeting both hospital-based and remote health monitoring environments. Fragmentation Detection Algorithm (FDA) was designed and modeled using PhysioNet's PTBDB and upon reiterative refinements it successfully detected all discontinuities in the QRS complex. The QRS complexes of 31 patients obtained randomly from PhysioNet's PTBDB were examined by two experienced cardiologists and the measurements obtained were compared with the results of our proposed FDA leading to 89.8% agreement among them. PMID:24110556

Maheshwari, Sidharth; Acharyya, Amit; Puddu, Paolo Emilio; Schiariti, Michele

2013-01-01

12

Identification of three novel genetic variations associated with electrocardiographic traits (QRS duration and PR interval) in East Asians.  

PubMed

The electrocardiogram has several advantages in detecting cardiac arrhythmia-it is readily available, noninvasive and cost-efficient. Recent genome-wide association studies have identified single-nucleotide polymorphisms that are associated with electrocardiogram measures. We performed a genome-wide association study using Korea Association Resource data for the discovery phase (Phase 1, n = 6805) and two consecutive replication studies in Japanese populations (Phase 2, n = 2285; Phase 3, n = 5010) for QRS duration and PR interval. Three novel loci were identified: rs2483280 (PRDM16 locus) and rs335206 (PRDM6 locus) were associated with QRS duration, and rs17026156 (SLC8A1 locus) correlated with PR interval. PRDM16 was recently identified as a causative gene of left ventricular non-compaction and dilated cardiomyopathy in 1p36 deletion syndrome, which is characterized by heart failure, arrhythmia and sudden cardiac death. Thus, our finding that a PRDM16 SNP is linked to QRS duration strongly implicates PRDM16 in cardiac function. In addition, C allele of rs17026156 increases PR interval (beta ± SE, 2.39 ± 0.40 ms) and exists far more frequently in East Asians (0.46) than in Europeans and Africans (0.05 and 0.08, respectively). PMID:25035420

Hong, Kyung-Won; Lim, Ji Eun; Kim, Jong Wook; Tabara, Yasuharu; Ueshima, Hirotsugu; Miki, Tetsuro; Matsuda, Fumihiko; Cho, Yoon Shin; Kim, Yeonjung; Oh, Bermseok

2014-12-15

13

Electrocardiography series. Narrow QRS-complex tachycardia: Part 2.  

PubMed

We discuss two cases of incessant atrial tachycardia (AT), including the presentation and clinical course. It is important to differentiate AT from other causes of supraventricular tachycardia, such as atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT), as it would have implications on clinical management. Electrocardiographic features of AT, especially the presence of an AV Wenckebach phenomenon with 'grouped beating', are critical for differentiating AT from AVRT and AVNRT. It is also vital to identify the P waves and their relations to QRS on electrocardiography, as this would aid in the differentiation of various supraventricular tachycardias. PMID:25273927

Singh, D; Teo, S G; Omar, A R; Poh, K K

2014-09-01

14

The influence of coincidence of fetal and maternal QRS complexes on fetal heart rate reliability  

Microsoft Academic Search

Bioelectrical fetal heart activity being recorded from maternal abdominal surface contains more information than mechanical heart activity measurement based on the Doppler ultrasound signals. However, it requires extraction of fetal electrocardiogram from abdominal signals where the maternal electrocardiogram is dominant. The simplest technique for maternal component suppression is a blanking procedure, which relies upon the replacement of maternal QRS complexes

Adam Matonia; Janusz Jezewski; Tomasz Kupka; Krzysztof Horoba; Janusz Wrobel; Adam Gacek

2006-01-01

15

An efficient unsupervised fetal QRS complex detection from abdominal maternal ECG.  

PubMed

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

Varanini, M; Tartarisco, G; Billeci, L; Macerata, A; Pioggia, G; Balocchi, R

2014-08-01

16

A FPGA system for QRS complex detection based on Integer Wavelet Transform  

NASA Astrophysics Data System (ADS)

Due to complexity of their mathematical computation, many QRS detectors are implemented in software and cannot operate in real time. The paper presents a real-time hardware based solution for this task. To filter ECG signal and to extract QRS complex it employs the Integer Wavelet Transform. The system includes several components and is incorporated in a single FPGA chip what makes it suitable for direct embedding in medical instruments or wearable health care devices. It has sufficient accuracy (about 95%), showing remarkable noise immunity and low cost. Additionally, each system component is composed of several identical blocks/cells what makes the design highly generic. The capacity of today existing FPGAs allows even dozens of detectors to be placed in a single chip. After the theoretical introduction of wavelets and the review of their application in QRS detection, it will be shown how some basic wavelets can be optimized for easy hardware implementation. For this purpose the migration to the integer arithmetic and additional simplifications in calculations has to be done. Further, the system architecture will be presented with the demonstrations in both, software simulation and real testing. At the end, the working performances and preliminary results will be outlined and discussed. The same principle can be applied with other signals where the hardware implementation of wavelet transform can be of benefit.

Stojanovi?, R.; Karadagli?, D.; Mirkovi?, M.; Miloševi?, D.

2011-01-01

17

Is nurse interpretation of the ECG QRS width reliable?  

PubMed

Electrocardiogram (ECG) data are critical in formulating management strategies following sodium channel antagonist overdose. Poison centers frequently rely on verbal reports of the ECG obtained from bedside nurses. No previous study has addressed the quality of ECG data obtained in this manner. Therefore, we sought to test the ability of nurses to recognize and measure a widened QRS complex, the hallmark of myocardial sodium channel toxicity. Thirty-six emergency department and critical care nurses employed at a tertiary care hospital participated in this prospective study. The study subjects were divided into three groups and asked to interpret 12 ECGs (five normal and seven wide QRS). For each ECG, participants (1) determined if the QRS was narrow or wide and (2) measured the QRS duration. The groups differed in delivery of instruction regarding QRS measurement. Group 1 received visual instructions; group 2 received scripted verbal instructions, and group 3 served as controls, receiving no specific QRS measurement instructions. The nurse data was compared with physician interpretation (consensus of three physicians). Between-group analysis tested for impact of potential real-time educational intervention. Overall, the nurses identified a wide QRS complex most of the time (77%), but had difficulty in accurately measuring the QRS duration (44%). Real-time visual or verbal instruction did not improve accuracy (p?=?NS between groups). The results suggest that verbal ECG data from nurse callers is not sufficient to make an accurate clinical assessment in the setting of sodium channel poisoning. PMID:22215289

Zimmerman, Tonia; Beuhler, Michael C; Kerns, William

2012-06-01

18

Wavelets for QRS Detection.  

National Technical Information Service (NTIS)

This paper examines the use of wavelets for the detection of QRS complex in ECG. Wavelets provide temporal and spectral information simultaneously and offer flexibility with a choice of wavelet functions with different properties. This research has examin...

H. A. Dinh, D. K. Kumar, N. D. Pah, P. Burton

2001-01-01

19

Radial dyssynchrony assessed by cardiovascular magnetic resonance in relation to left ventricular function, myocardial scarring and QRS duration in patients with heart failure  

PubMed Central

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

2009-01-01

20

Heterogeneous effect of quinidine on the ventricular depolarization process assessed by the spatial velocity electrocardiogram of the QRS complex. Preliminary report of a new investigative method.  

PubMed

The negative conduction effect of quinidine on each of the successive phases of the ventricular depolarization was investigated using an original noninvasive method: the spatial velocity electrocardiogram of the QRS complex (SVECG-QRS). We performed a randomized placebo-controlled trial in 10 healthy subjects with a single oral dose of quinidine (330 mg) or placebo. Electrocardiographic acquisition and processing (220 recordings for the complete trial) were performed using the Lyon vectorcardiographic program. For each SVECG-QRS curve, the position of seven specific points from A (onset of QRS) to G (end of QRS) were determined precisely. The six successive time intervals between these points (AB-FG) and five velocity values (B-F) were then calculated. The QRS complex was longer under quinidine than placebo (102.4 +/- 1.6 vs. 100.3 +/- 1.5 ms). The difference was at the periphery of statistical significance (p = 0.05), and this lack of statistical difference may be mainly due to the low serum levels of quinidine obtained at the peak of the concentration (1.46 +/- 0.4 mg/1). All six QRS time intervals were longer under quinidine, but only the BC interval was significantly different (9.3 +/- 1.1 vs. 18.8 +/- 1.1 ms; p < 0.05) suggesting a more pronounced negative conduction effect at the onset of ventricular depolarization. No significant modifications were observed for the velocity values. We conclude that (1) the negative conduction effect of quinidine is heterogeneous, but a further study with a higher dose of quinidine (concentration-dependent effect) is required to confirm this hypothesis and (2) the spatial velocity electrocardiogram of the QRS complex allows a detailed analysis of the ventricular conduction phases. The results of the measurement were found to be reproducible. This noninvasive tool could be used in clinical practice to assess effects of antiarrhythmic drugs on successive ventricular depolarization phases. PMID:8653729

Fareh, S; Arnaud, P; Fayn, J; Nony, P; Girard, P; Haugh, M; Girard, I; Ferry, S; Boissel, J P; Rubel, P

1996-01-01

21

Influence of QRS complex detection errors on entropy algorithms. Application to heart rate variability discrimination.  

PubMed

Signal entropy measures such as approximate entropy (ApEn) and sample entropy (SampEn) are widely used in heart rate variability (HRV) analysis and biomedical research. In this article, we analyze the influence of QRS detection errors on HRV results based on signal entropy measures. Specifically, we study the influence that QRS detection errors have on the discrimination power of ApEn and SampEn using the cardiac arrhythmia suppression trial (CAST) database. The experiments assessed the discrimination capability of ApEn and SampEn under different levels of QRS detection errors. The results demonstrate that these measures are sensitive to the presence of ectopic peaks: from a successful classification rate of 100%, down to a 75% when spikes are present. The discriminating capability of the metrics degraded as the number of misdetections increased. For an error rate of 2% the segmentation failed in a 12.5% of the experiments, whereas for a 5% rate, it failed in a 25%. PMID:23246085

Molina-Picó, Antonio; Cuesta-Frau, David; Miró-Martínez, Pau; Oltra-Crespo, Sandra; Aboy, Mateo

2013-04-01

22

Design of a cardiac monitor in terms of parameters of QRS complex.  

PubMed

Objective. To design a portable cardiac monitor system based on the available ordinary ECG machine and works on the basis of QRS parameters. Method. The 80196 single chip microcomputer was used as the central microprocessor and real time electrocardiac signal was collected and analyzed [correction of analysized] in the system. Result. Apart from the performance of an ordinary monitor, this machine possesses also the following functions: arrhythmia analysis, HRV analysis, alarm, freeze, and record of automatic papering. Convenient in carrying, the system is powered by AC or DC sources. Stability, low power and low cost are emphasized in the hardware design; and modularization method is applied in software design. Conclusion. Popular in usage and low cost made the portable monitor system suitable for use under simple conditions. PMID:12422858

Chen, Zhen-cheng; Ni, Li-li; Su, Ke-ping; Wang, Hong-yan; Jiang, Da-zong

2002-08-01

23

QRS Complex Enlargement as a Predictor of Ventricular Arrhythmias in Patients Affected by Surgically Treated Tetralogy of Fallot: A Comprehensive Literature Review and Historical Overview  

PubMed Central

Tetralogy of Fallot (TOF) is a congenital heart disease frequently treated by surgical repair to relieve symptoms and improve survival. However, despite the performing of an optimal surgical repair, TOF patients are at times characterized by a poor long-term survival rate, likely due to cardiac causes such as ventricular arrhythmias, with subsequent sudden death. In the 80s it was irrefutably demonstrated that QRS prolongation ?180?msec at basal electrocardiogram is a strong predictor for refining risk stratification for ventricular tachycardia in these patients. The aim of this research was to undertake a review of all studies conducted to assess the impact of QRS duration on the development of life-threatening ventricular arrhythmias in repaired TOF subjects. PMID:23509638

Bassareo, Pier Paolo; Mercuro, Giuseppe

2013-01-01

24

High Frequency QRS ECG Accurately Detects Cardiomyopathy  

NASA Technical Reports Server (NTRS)

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.

Schlegel, Todd T.; Arenare, Brian; Poulin, Gregory; Moser, Daniel R.; Delgado, Reynolds

2005-01-01

25

QRS Slopes for Detection and Characterization of Myocardial Ischemia  

Microsoft Academic Search

In this study, the upward (IUS) and downward (IDS) slopes of the QRS complex are proposed as indices for quantifying ischemia-induced electrocardiogram (ECG) changes. Using ECG recordings acquired before and during percutaneous transluminal coronary angioplasty (PTCA), it is found that the QRS slopes are considerably less steep during artery occlusion, in particular for IDS. With respect to ischemia detection, the

Esther Pueyo; Leif Sörnmo; Pablo Laguna

2008-01-01

26

An automated algorithm for online detection of fragmented QRS and identification of its various morphologies.  

PubMed

Fragmented QRS (f-QRS) has been proven to be an efficient biomarker for several diseases, including remote and acute myocardial infarction, cardiac sarcoidosis, non-ischaemic cardiomyopathy, etc. It has also been shown to have higher sensitivity and/or specificity values than the conventional markers (e.g. Q-wave, ST-elevation, etc.) which may even regress or disappear with time. Patients with such diseases have to undergo expensive and sometimes invasive tests for diagnosis. Automated detection of f-QRS followed by identification of its various morphologies in addition to the conventional ECG feature (e.g. P, QRS, T amplitude and duration, etc.) extraction will lead to a more reliable diagnosis, therapy and disease prognosis than the state-of-the-art approaches and thereby will be of significant clinical importance for both hospital-based and emerging remote health monitoring environments as well as for implanted ICD devices. An automated algorithm for detection of f-QRS from the ECG and identification of its various morphologies is proposed in this work which, to the best of our knowledge, is the first work of its kind. Using our recently proposed time-domain morphology and gradient-based ECG feature extraction algorithm, the QRS complex is extracted and discrete wavelet transform (DWT) with one level of decomposition, using the 'Haar' wavelet, is applied on it to detect the presence of fragmentation. Detailed DWT coefficients were observed to hypothesize the postulates of detection of all types of morphologies as reported in the literature. To model and verify the algorithm, PhysioNet's PTB database was used. Forty patients were randomly selected from the database and their ECG were examined by two experienced cardiologists and the results were compared with those obtained from the algorithm. Out of 40 patients, 31 were considered appropriate for comparison by two cardiologists, and it is shown that 334 out of 372 (89.8%) leads from the chosen 31 patients complied favourably with our proposed algorithm. The sensitivity and specificity values obtained for the detection of f-QRS were 0.897 and 0.899, respectively. Automation will speed up the detection of fragmentation, reducing the human error involved and will allow it to be implemented for hospital-based remote monitoring and ICD devices. PMID:24132202

Maheshwari, Sidharth; Acharyya, Amit; Puddu, Paolo Emilio; Mazomenos, Evangelos B; Leekha, Gourav; Maharatna, Koushik; Schiariti, Michele

2013-12-01

27

Real-time, high frequency QRS electrocardiograph  

NASA Technical Reports Server (NTRS)

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.

Schlegel, Todd T. (Inventor); DePalma, Jude L. (Inventor); Moradi, Saeed (Inventor)

2006-01-01

28

Prosodic complexity and phrase length as factors in pause duration  

NASA Astrophysics Data System (ADS)

Research on pauses has mainly focused on predicting the likelihood of pause occurrence and on the effect of syntactic structure on pause duration within an utterance. Very little is known about what factors, apart from syntactic and discourse factors, influence the length of pauses between utterances or phrases. This experiment examines the effect of prosodic structure and phrase length on pause duration. Subjects read 24 English sentences varying along the following parameters: (a) the length in syllables of the intonational phrase preceding and following the pause and (b) the prosodic structure of the intonational phrase preceding and following the pause, specifically whether or not the intonational phrase branches into smaller phrases. In order to minimize variability due to speech rate and individual differences, speakers read sentences synchronously in dyads (Cummins, 2002; Zvonik and Cummins, 2002). The results show that length has a significant effect on pause duration both pre- and postboundary for all dyads, and that prosodic complexity has a significant postboundary effect for some dyads. The possible reasons for the observed pause duration effects and the implications of these results on the question of incrementality in speech production are discussed. [Work supported by NIH DC03172.

Krivokapic, Jelena

2001-05-01

29

A new QRS detection method using wavelets and artificial neural networks.  

PubMed

We present a new method for detection and classification of QRS complexes in ECG signals using continuous wavelets and neural networks. Our wavelet method consists of four wavelet basis functions that are suitable in detection of QRS complexes within different QRS morphologies in the signal and thresholding technique for denoising and feature extraction. The results demonstrate that the proposed method is not only efficient for normal ECG signal analysis but also for various types of arrhythmic cardiac signals embedded in noise. For the classification stage, a feedforward neural network was trained with standard backpropagation algorithm. The classifier input features consisted of compact wavelet coefficients of QRS complexes that resulted in higher classification rates. We demonstrate the efficiency of our method with the average accuracy 97.2% in classification of normal and abnormal QRS complexes. PMID:20703782

Abibullaev, Berdakh; Seo, Hee Don

2011-08-01

30

Microcontroller-based real-time QRS detection.  

PubMed

The authors describe the design of a system for real-time detection of QRS complexes in the electrocardiogram based on a single-chip microcontroller (Motorola 68HC811). A systematic analysis of the instrumentation requirements for QRS detection and of the various design techniques is also given. Detection algorithms using different nonlinear transforms for the enhancement of QRS complexes are evaluated by using the ECG database of the American Heart Association. The results show that the nonlinear transform involving multiplication of three adjacent, sign-consistent differences in the time domain gives a good performance and a quick response. When implemented with an appropriate sampling rate, this algorithm is also capable of rejecting pacemaker spikes. The eight-bit single-chip microcontroller provides sufficient throughput and shows a satisfactory performance. Implementation of multiple detection algorithms in the same system improves flexibility and reliability. The low chip count in the design also favors maintainability and cost-effectiveness. PMID:1450792

Sun, Y; Suppappola, S; Wrublewski, T A

1992-01-01

31

The Spatial QRS-T Angle: Implications in Clinical Practice  

PubMed Central

The ventricular gradient (VG) as a concept was conceived in the 1930s and its calculation yielded information that was not otherwise obtainable. The VG was not utilized by clinicians at large because it was not easy to understand and its computation time-consuming. The contemporary spatial QRS-T angle is based on the concept of the VG and defined as its mathematical and physiological integral. Its current major clinical use is to assess the cardiac primary repolarization abnormalities in 3-dimensional spatial vectorial plans which are normally untraced in the presence of secondary electrophysiological activity in a 2-dimensional routine electrocardiogram (ECG). Currently the calculation of the spatial QRS-T angle can be easily computed on the basis of a classical ECG and contributes to localization of arrhythmogenic areas in the heart by assessing overall and local heterogeneity of the myocardial ventricular action potention duration. Recent population-based studies suggest that the spatial QRS-T angle is a dominant ECG predictor of future cardiovascular events and death and it is superior to more conventional ECG parameters. Its assessment warrants consideration for intensified primary and secondary cardiovascular prevention efforts and should be included in everyday clinical practice. This review addresses the nature and diagnostic potential of the spatial QRS-T angle. The main focus is its role in ECG assessment of dispersion of repolarization, a key factor in arrythmogeneity. PMID:23909632

Voulgari, Christina; Pagoni, Stamatina; Tesfaye, Solomon; Tentolouris, Nicholas

2013-01-01

32

A method for context-based adaptive QRS clustering in real-time  

E-print Network

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...

Castro, Daniel; Presedo, Jesús

2014-01-01

33

QRS Prolongation in Myotonic Muscular Dystrophy and Diffuse Fibrosis on Cardiac Magnetic Resonance  

PubMed Central

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

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.

2011-01-01

34

QRS detection using S-Transform and Shannon energy.  

PubMed

This paper presents a novel method for QRS detection in electrocardiograms (ECG). It is based on the S-Transform, a new time frequency representation (TFR). The S-Transform provides frequency-dependent resolution while maintaining a direct relationship with the Fourier spectrum. We exploit the advantages of the S-Transform to isolate the QRS complexes in the time-frequency domain. Shannon energy of each obtained local spectrum is then computed in order to localize the R waves in the time domain. Significant performance enhancement is confirmed when the proposed approach is tested with the MIT-BIH arrhythmia database (MITDB). The obtained results show a sensitivity of 99.84%, a positive predictivity of 99.91% and an error rate of 0.25%. Furthermore, to be more convincing, the authors illustrated the detection parameters in the case of certain ECG segments with complicated patterns. PMID:24856322

Zidelmal, Z; Amirou, A; Ould-Abdeslam, D; Moukadem, A; Dieterlen, A

2014-08-01

35

Recovery of High-Frequency QRS Potentials Following Cardioplegic Arrest in Pediatric Cardiac Surgery  

Microsoft Academic Search

We examined the hypothesis that recovery of high-frequency QRS potentials at reperfusion is influenced by the duration of myocardial ischemia during cardioplegic arrest in pediatric cardiac surgery. Signal-averaged electrocardiograms were recorded after induction of anesthesia (baseline data) and every 1 to 5 minutes after aortic declamping in 14 patients aged 2 months to 6 years. The signals were processed with

M. Abe; N. Atsumi; S. Matsushita; T. Mitsui

2001-01-01

36

The Presence of Fragmented QRS on 12-Lead Electrocardiography in Patients with Coronary Artery Ectasia  

PubMed Central

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.

Sen, Fatih; Kuyumcu, Mevlut Serdar; Ozeke, Ozcan; Balc?, Mustafa Mucahit; Aydogdu, Sinan

2014-01-01

37

Principal component model for maternal ECG extraction in fetal QRS detection.  

PubMed

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 1 min 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 4.84 ms RMS error for fetal RR-interval estimation were acquired. PMID:25069651

Lipponen, Jukka A; Tarvainen, Mika P

2014-08-01

38

Assessment of the relationship between red cell distribution width and fragmented QRS in patients with non-ST elevated acute coronary syndrome  

PubMed Central

Background Red cell distribution width (RDW) and fragmented QRS (fQRS) complexes have also been reported to be predictors of cardiac events and all-cause mortality in coronary artery disease (CAD). We aimed to investigate the association of serum red cell distribution width (RDW) levels and fQRS in patients with non-ST elevated acute coronary syndrome (NST-ACS). Material/Methods We retrospectively evaluated a total of 251 patients (191 men and 60 women) with NST-ACS. The NST-ACS consisted of unstable angina (UA) and non-ST elevated myocardial infarction (NSTEMI). The fQRS pattern was defined as the presence of an additional R’ or crochetage wave, notching in the nadir of the S wave or fragmentation of the RS or QS complexes in 2 contiguous leads corresponding to a major coronary artery territory. The relationships between the RDW and fQRS were assessed. Results The patients in the fQRS group were older, left ventricular ejection fraction (LVEF) levels were significantly lower, and baseline RDW and troponin levels were significantly higher than in the group without fQRS. There were positive correlations between age, number of coronary arteries narrowed, and RDW, and negative correlations between triglyceride, LVEF, and RDW in study patients. There were positive correlations between number of fQRS leads, age, and RDW, and negative correlations between triglyceride, LVEF, and RDW in NSTEMI patients. Conclusions Our results indicate that an elevated RDW values is associated with fQRS in NST-ACS. Elevated RDW values and fQRS together may be useful for identifying NSTEMI patients in NST-ACS. PMID:24621882

Bekler, Adem; Gazi, Emine; Tenekecioglu, Erhan; Karaagac, Kemal; Altun, Burak; Temiz, Ahmet; Barutcu, Ahmet; Peker, Tezcan; Aslan, Burhan; Y?lmaz, Mustafa

2014-01-01

39

Mississippi Quality Step System: QRS Profile. The Child Care Quality Rating System (QRS)Assessment  

ERIC Educational Resources Information Center

This paper presents a profile of Mississippi's Quality Step 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) Application…

Child Trends, 2010

2010-01-01

40

Iowa Child Care Quality Rating System: QRS Profile. The Child Care Quality Rating System (QRS) Assessment  

ERIC Educational Resources Information Center

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;…

Child Trends, 2010

2010-01-01

41

Relations between QRS|T Angle, Cardiac Risk Factors, and Mortality in the Third National Health and Nutrition Examination Survey (NHANES III)  

PubMed Central

On the surface electrocardiogram (ECG), an abnormally wide QRS|T angle reflects changes in regional action potential duration profiles and in direction of repolarization sequence which is thought to increase the risk of ventricular arrhythmia. We investigated the relationship between abnormal QRS|T angle and mortality in a nationally representative sample of individuals without clinically evident heart disease. We studied 7,052 participants ? 40 years of age in the Third National Health and Nutrition Examination Survey (NHANES III) with 12-lead ECGs. Individuals with self-report or ECG evidence of a prior myocardial infarction, QRS duration ?120 msec, or history of heart failure were excluded. Borderline and abnormal spatial QRS|T angle were defined according to sex-specific 75th and 95th percentiles of frequency distributions. All-cause (n=1093 women, n=1191 men) and cardiovascular mortality (n=462 women, n=455 men) over 14 years was assessed through linkage with the National Death Index. In multivariable analyses, abnormal spatial QRS|T angle was associated with an increased hazard ratio (HR) for cardiovascular mortality in women (HR 1.82, 95% CI 1.05-3.14) and men (HR 2.21, 95% CI 1.32-3.68). An abnormal QRS|T angle was also associated with increased multivariable adjusted HRs for all-cause mortality in women (HR 1.30, 95% CI 0.95-1.78) and men (HR 1.87, 95% CI 1.29-2.7). Borderline QRS|T angle was not associated with increased risk for all-cause or cardiovascular mortality. In conclusion, abnormal QRS|T angle, as measured on a 12-lead ECG, was associated with increased risk for cardiovascular and all-cause mortality in this population-based sample without known heart disease. PMID:22221946

Whang, William; Shimbo, Daichi; Levitan, Emily B.; Newman, Jonathan D.; Rautaharju, Pentti M.; Davidson, Karina W.; Muntner, Paul

2012-01-01

42

An Improved QRS Wave Group Detection Algorithm and Matlab Implementation  

NASA Astrophysics Data System (ADS)

This paper presents an algorithm using Matlab software to detect QRS wave group of MIT-BIH ECG database. First of all the noise in ECG be Butterworth filtered, and then analysis the ECG signal based on wavelet transform to detect the parameters of the principle of singularity, more accurate detection of the QRS wave group was achieved.

Zhang, Hongjun

43

Increased omega complexity and decreased microstate duration in nonmedicated schizophrenic patients.  

PubMed

To explore brain functions in schizophrenic patients, the global analytic strategy of multichannel EEG was performed that combines measures of global complexity (Omega), total power (Sigma) and generalized frequency (Phi), and EEG microstate analysis was applied to multichannel EEG data for 24 nonmedicated patients and 24 healthy subjects. The patients had higher Omega and Sigma values, and lower Phi values compared with healthy subjects. Three topographical classes were obtained from all EEG data by EEG microstate analysis. The mean duration of one topographical class in the patients was shortened compared to healthy subjects. These results indicated looser cooperativity, or decreased connectivity of the active brain process and deviant brain information processing in schizophrenic patients. PMID:17199099

Irisawa, Satoshi; Isotani, Toshiaki; Yagyu, Takami; Morita, Sachi; Nishida, Keiichiro; Yamada, Keizo; Yoshimura, Masafumi; Okugawa, Gaku; Nobuhara, Kenji; Kinoshita, Toshihiko

2006-01-01

44

Real-time, high frequency QRS electrocardiograph with reduced amplitude zone detection  

NASA Technical Reports Server (NTRS)

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.

Schlegel, Todd T. (Inventor); DePalma, Jude L. (Inventor); Moradi, Saeed (Inventor)

2009-01-01

45

Noninvasive fetal QRS detection using an echo state network and dynamic programming.  

PubMed

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

Lukoševi?ius, Mantas; Marozas, Vaidotas

2014-08-01

46

[Wide QRS tachycardia preceded by pacemaker spikes].  

PubMed

The differential diagnosis and therapeutic management of wide QRS tachycardia preceded by pacemaker spike is presented. The pacemaker-mediated tachycardia, tachycardia fibrillo-flutter in patients with pacemakers, and runaway pacemakers, have a similar surface electrocardiogram, but respond to different therapeutic measures. The tachycardia response to the application of a magnet over the pacemaker could help in the differential diagnosis, and in some cases will be therapeutic, as in the case of a tachycardia-mediated pacemaker. Although these conditions are diagnosed and treated in hospitals with catheterization laboratories using the application programmer over the pacemaker, patients presenting in primary care clinic and emergency forced us to make a diagnosis and treat the haemodynamically unstable patient prior to referral. PMID:23768570

Romero, M; Aranda, A; Gómez, F J; Jurado, A

2014-04-01

47

Variation in canopy duration in the perennial biofuel crop Miscanthus reveals complex associations with yield  

PubMed Central

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

Robson, Paul R.H.

2013-01-01

48

Month-to-month and year-to-year reproducibility of high frequency QRS ECG signals  

NASA Technical Reports Server (NTRS)

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.

Batdorf, Niles J.; Feiveson, Alan H.; Schlegel, Todd T.

2004-01-01

49

Month-to-Month and Year-to-Year Reproducibility of High Frequency QRS ECG signals  

NASA Technical Reports Server (NTRS)

High frequency (HF) 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. We therefore prospectively investigated the reproducibility of the root mean squared (RMS) voltage, kurtosis, and the presence versus absence of reduced amplitude zones (RAzs) in signal averaged 12-lead HF QRS recordings acquired in the supine position one month apart in 16 subjects and one year apart in 27 subjects. Reproducibility of RMS 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 RMS voltage was 12% month-to-month and 16% year-to-year in the serial recordings when averaged over all 12 leads. RAzs were also reproducible at a rate of up to 87% and 8 1 %, respectively, for the month-to-month and year-to-year recordings. We conclude that 12-lead HF QRS electrocardiograms are sufficiently reproducible for clinical use.

Batdorf, Niles; Feiveson, Alan H.; Schlegel, Todd T.

2006-01-01

50

Progress in resolving the duration of magmatism in the Paleoproterozoic Bushveld Complex  

NASA Astrophysics Data System (ADS)

Determining precise crystallization ages and assessing the duration of magmatism associated with the Paleoproterozoic Bushveld Complex, the world's largest layered intrusion located in the northern Kaapvaal craton of South Africa, is critical for establishing the genetic relations among its different rock units (Rustenburg Layered Suite, overlying Rooiberg Group felsic volcanic rocks, intrusive Rashoop Granophyres). We report chemical abrasion ID-TIMS U-Pb zircon results (weighted 207Pb/206Pb ages) for samples spanning the uppermost ~3/4 of the igneous stratigraphy of the layered mafic rocks and the roof. The temporal relationship between the Upper Zone and the roof from the Eastern Limb is constrained by the age of a diorite ~52 m below the roof (2056.52 ± 0.81 Ma; n = 6 single grains) and a granodiorite mixed with hornfels (40:60) and interpreted as partially melted roof material (2054.83 ± 0.86 Ma; n = 7). The slightly younger age of the granodiorite may indicate that the overlying melt sheet was kept molten due to continued influx of the latent heat of crystallization from the underlying 8 km-thick stack of cooling cumulates. The PGE-rich Merensky Reef and the UG2 chromitite occur in the Upper Critical Zone above the ultramafic rocks that comprise the base of the complex. Two samples from the Merensky Reef, separated by ~300 km, have overlapping ages: a sample from Farm Driekop in the Eastern Limb yields an age of 2055.30 ± 0.61 Ma (n = 10) and a sample from the Rustenburg mining section in the Western Limb an age of 2056.13 ± 0.70 Ma (n = 8; age revised from [1]). These ages are indistinguishable from the Upper Zone diorite indicating rapid construction of the upper 2/3 of the Bushveld Complex at ca. 2056 Ma. Preliminary results for zircon from a feldspathic orthopyroxenite immediately beneath the UG2 chromitite (Middelpunt mine, Eastern Limb), ~380 m below the Merensky Reef, reveal unusual U-Pb systematics with low U concentrations (2-27 ppm), exceptionally high Th/U (7.3-28.1) and a range of 207Pb/206Pb ages (2057.8 to 2075.0 Ma; n = 6, all results concordant). These results may reflect a combination of the compositional effects of co-existing U-bearing accessory phases (apatite, rutile) and formation by metasomatism and partial melting of the pyroxenite protolith by rising hydrous interstitial melt that accumulated beneath the impermeable chromitite layer [2]. The ages for additional samples in progress will also be presented to further test the proposal that 15-25% of the original magma volume in the intrusion was expelled to form the Upper Rooiberg Group lavas or Rashoop granophyres [3]. [1] Scoates & Friedman (2008) Economic Geology 103, 465-471; [2] Mathez & Mey (2005) Economic Geology 100, 1616-1630; [3] VanTongeren et al. (2010) Journal of Petrology 51, 1891-1912.

Scoates, J. S.; Wall, C. J.; Friedman, R. M.; VanTongeren, J. A.; Mathez, E. A.

2011-12-01

51

A precision ECG signal generator providing full Lead II QRS amplitude variability and an accurate timing profile.  

PubMed

This paper reports the design and development of a precision ECG signal generator intended for use in test and calibration of electrocardiographic equipment, ECG signal processing systems and as a cardiac teaching tool. It generates a Lead II signal which maintains the timing and profile characteristics of a Lead II electrocardiograph signal across a range of heart rates between 45 and 185 bpm in 1 bpm steps. The QRS amplitude can be adjusted in 1 microV increments from 100 microV to 10 mV. The up-slope of the QRS can be set between 15 ms and 45 ms with 1 ms resolution. The P and T wave amplitudes can be adjusted as a 1-100% scaling of the QRS complex amplitude with a 1% resolution. A color LCD with touch screen capability provides the user with facilities for inputting parameters, viewing the output wave parameters and a graphical representation of the resulting output waveform. The signal generator outputs a precision differential signal via a digital to analogue stage which has been designed using low noise techniques to produce accurate signals at the lower end of the QRS amplitude range. PMID:19963789

Shorten, Gavin P; Burke, Martin J

2009-01-01

52

Prosodic Planning: Effects of Phrasal Length and Complexity on Pause Duration  

PubMed Central

Research on pause duration has mainly focused on the impact of syntactic structure on the duration of pauses within an utterance and on the impact of syntax, discourse, and prosodic structure on the likelihood of pause occurrence. Relatively little is known about what factors play a role in determining the duration of pauses between utterances or phrases. Two experiments examining the effect of prosodic structure and phrase length on pause duration are reported. Subjects read sentences varying along the following parameters: a) the length in syllables of the intonational phrase preceding and following the pause, and b) the prosodic structure of the intonational phrase preceding and following the pause, specifically whether or not the intonational phrase branches into smaller phrases. In order to minimize variability due to speech rate and individual differences, speakers read sentences synchronously in dyads. The results showed a significant post-boundary effect of prosodic branching and significant pre- and post-boundary phrase length effects. The results are discussed in terms of production units. PMID:18379639

Krivokapi, Jelena

2007-01-01

53

Aviation System Analysis Capability (ASAC) Quick Response System (QRS) Test Report  

NASA Technical Reports Server (NTRS)

This document is the Aviation System Analysis Capability (ASAC) Quick Response System (QRS) Test Report. The purpose of this document is to present the results of the QRS unit and system tests in support of the ASAC QRS development effort. This document contains an overview of the project background and scope, defines the QRS system and presents the additions made to the QRS this year, explains the assumptions, constraints, and approach used to conduct QRS Unit and System Testing, and presents the schedule used to perform QRS Testing. The document also presents an overview of the Logistics Management Institute (LMI) Test Facility and testing environment and summarizes the QRS Unit and System Test effort and results.

Roberts, Eileen; Villani, James A.; Ritter, Paul

1997-01-01

54

[A research on real-time ventricular QRS classification methods for single-chip-microcomputers].  

PubMed

Ventricular QRS classification is key technique of ventricular arrhythmias detection in single-chip-microcomputer based dynamic electrocardiogram real-time analyser. This paper adopts morphological feature vector including QRS amplitude, interval information to reveal QRS morphology. After studying the distribution of QRS morphology feature vector of MIT/BIH DB ventricular arrhythmia files, we use morphological feature vector cluster to classify multi-morphology QRS. Based on the method, morphological feature parameters changing method which is suitable to catch occasional ventricular arrhythmias is presented. Clinical experiments verify missed ventricular arrhythmia is less than 1% by this method. PMID:11189347

Peng, L; Yang, Z; Li, L; Chen, H; Chen, E; Lin, J

1997-05-01

55

Real Time QRS Detection Based on M-ary Likelihood Ratio Test on the DFT Coefficients.  

PubMed

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

Górriz, Juan Manuel; Ramírez, Javier; Olivares, Alberto; Padilla, Pablo; Puntonet, Carlos G; Cantón, Manuel; Laguna, Pablo

2014-01-01

56

Real Time QRS Detection Based on M-ary Likelihood Ratio Test on the DFT Coefficients  

PubMed Central

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

Górriz, Juan Manuel; Ramírez, Javier; Olivares, Alberto; Padilla, Pablo; Puntonet, Carlos G.; Cantón, Manuel; Laguna, Pablo

2014-01-01

57

Products of the complex, long duration, AD 1305 rhyolitic eruption of Tarawera, New Zealand  

Microsoft Academic Search

The youngest rhyolite eruption in New Zealand is the ~4 km3 (DRE) Kaharoa eruption episode from Tarawera volcano at ~1305AD. The complex eruption sequence occurred from seven magmatic vents which define an 8-km linear fissure across the volcano. The main events were: 1) phreatic blasts; 2) sub-plinian\\/plinian eruptions dispersing fallout over the northeastern North Island; 3) a rhyolite dome extrusion;

S. Self; C. R. Scutter; I. A. Nairn; S. T. Sahetapy-Engel

2001-01-01

58

Complex Biventricular Pacing - A Case Series  

PubMed Central

It is established that cardiac resynchronisation therapy (CRT) reduces mortality and hospitalisation and improves functional class in patients with NYHA class 3-4 heart failure, an ejection fraction of ? 35% and a QRS duration of ? 120ms. Recent updates in the American guidelines have expanded the demographic of patients in whom CRT may be appropriate. Here we present two cases of complex CRT; one with a conventional indication but occluded central veins and the second with a novel indication for CRT post cardiac transplant. PMID:24493915

Hodkinson, Emily Catherine; Morrice, Keith; Loan, William; Nicholas, Jacob; Chew, EngWooi

2014-01-01

59

Frequency, origin, and outcome of ventricular premature complexes in patients with or without heart diseases.  

PubMed

The objective of the present study was to investigate the relation of ventricular premature complex (VPC) burden, origin, and electrocardiographic characteristics with left ventricular function and survival. Of 1,589 study patients, 388 (25%), 610 (38%), and 591 (37%) had low (<1,000/24 hours), moderate (1,000 to 10,000/24 hours), and high (>10,000/24 hours) VPC burden, respectively. Twenty-three percent of study patients had a left ventricular (LV) ejection fraction <50% (8% in low-, 20% in moderate-, and 36% in high-VPC-burden groups, p <0.001). High VPC burden was associated with lower LV ejection fraction in the presence (r = -0.17, p <0.001) and absence (r = -0.20, p <0.001) of heart diseases. The Kaplan-Meier survival estimates showed a significant difference among the 3 VPC burden groups (p = 0.046). The survival rates were significantly lower for patients with a VPC coupling interval of ?480 ms than those with a VPC coupling interval of <480 ms (p = 0.002) and lower for those with a VPC QRS duration of ?150 ms than those with a VPC QRS duration of <150 ms (p <0.001). In conclusion, high VPC burden is detrimental to LV systolic function. Broader VPC QRS duration and longer VPC coupling interval adversely impact on long-term survival. PMID:25205629

Lee, Ying-Hsiang; Zhong, Li; Roger, Veronique L; Asirvatham, Samuel J; Shen, Win-Kuang; Slusser, Joshua P; Hodge, David O; Cha, Yong-Mei

2014-11-01

60

High frequency QRS ECG predicts ischemic defects during myocardial perfusion imaging  

NASA Technical Reports Server (NTRS)

Changes in high frequency QRS components of the electrocardiogram (HF QRS ECG) (150-250 Hz) are more sensitive than changes in conventional ST segments for detecting myocardial ischemia. We investigated the accuracy of 12-lead HF QRS ECG in detecting ischemia during adenosine tetrofosmin myocardial perfusion imaging (MPI). 12-lead HF QRS ECG recordings were obtained from 45 patients before and during adenosine technetium-99 tetrofosmin MPI tests. Before the adenosine infusions, recordings of HF QRS were analyzed according to a morphological score that incorporated the number, type and location of reduced amplitude zones (RAZs) present in the 12 leads. During the adenosine infusions, recordings of HF QRS were analyzed according to the maximum percentage changes (in both the positive and negative directions) that occurred in root mean square (RMS) voltage amplitudes within the 12 leads. The best set of prospective HF QRS criteria had a sensitivity of 94% and a specificity of 83% for correctly identifying the MPI result. The sensitivity of simultaneous ST segment changes (18%) was significantly lower than that of any individual HF QRS criterion (P less than 0.00l). Analysis of 12-lead HF QRS ECG is highly sensitive and specific for detecting ischemic perfusion defects during adenosine MPI stress tests and significantly more sensitive than analysis of conventional ST segments.

2004-01-01

61

Monitoring complex trace-gas mixtures by long-path laser absorption spectrometry. [in long duration manned mission closed environments  

NASA Technical Reports Server (NTRS)

Laser-based spectrophotometric methods, which have been proposed for the detection of trace concentrations of gaseous contaminants, include Raman and passive radiometry. The paper discusses a simple long-path laser absorption method which is capable of resolving complex mixtures of closely related trace contaminants at ppm levels. A number of species were selected which are most likely to accumulate in closed environments, such as submarines or long-duration manned space flights. Absorption coefficients at CO2 laser wavelengths were measured, accurate to + 3 per cent or better, for each of these species. This data base was then used to determine the presence and concentration of the contaminants in prepared mixtures of 12 to 15 gases. Computer programs have been developed which will permit a real-time analysis of the monitored atmosphere. Minimum detectable concentrations for individual species are generally in the ppm range, and are not seriously degraded by interferences even in complex mixtures. Estimates of the dynamic range of this monitoring technique for various system configurations and comparison with other methods of analysis are discussed

Green, B. D.; Steinfeld, J. I.

1976-01-01

62

Real-Time, High-Frequency QRS Electrocardiograph  

NASA Technical Reports Server (NTRS)

An electronic system that performs real-time analysis of the low-amplitude, high-frequency, ordinarily invisible components of the QRS portion of an electrocardiographic signal in real time has been developed. Whereas the signals readily visible on a conventional electrocardiogram (ECG) have amplitudes of the order of a millivolt and are characterized by frequencies <100 Hz, the ordinarily invisible components have amplitudes in the microvolt range and are characterized by frequencies from about 150 to about 250 Hz. Deviations of these high-frequency components from a normal pattern can be indicative of myocardial ischemia or myocardial infarction

Schlegel, Todd T.; DePalma, Jude L.; Moradi, Saeed

2003-01-01

63

Automatic detection of end QRS notching or slurring.  

PubMed

The purpose of this study was to define criteria suited to automated detection of end QRS notching and slurring and to evaluate their accuracy. One hundred resting 12 lead ECGs from young adult men, split randomly into equal training and test sets, were examined independently by two reviewers for the presence of such notching or slurring. Consensus was reached by re-examination. Logic was added to the Glasgow resting ECG program to automate the detection of the phenomenon. After training, the automated detection had a sensitivity (SE) of 92.1% and a specificity (SP) of 96.6%. For the test set, SE was 90.5%, SP 96.5%. Two populations of healthy subjects--one Caucasian, one Nigerian--were analysed using the automated method. The prevalence of notching/slurring with peak/onset amplitude respectively ? 0.1 mV in two contiguous inferolateral leads was 23% and 29% respectively. In conclusion, the detection of end QRS notching or slurring can be automated with a high degree of accuracy. PMID:24360346

Clark, Elaine N; Katibi, Ibraheem; Macfarlane, Peter W

2014-01-01

64

A 0.83- ?W QRS detection processor using quadratic spline wavelet transform for wireless ECG acquisition in 0.35- ?m CMOS.  

PubMed

Healthcare electronics count on the effectiveness of the on-patient signal preprocessing unit to moderate the wireless data transfer for better power efficiency. In order to reduce the system power in long-time ECG acquisition, this work describes an on-patient QRS detection processor for arrhythmia monitoring. It extracts the concerned ECG part, i.e., the RR-interval between the QRS complex for evaluating the heart rate variability. The processor is structured by a scale-3 quadratic spline wavelet transform followed by a maxima modulus recognition stage. The former is implemented via a symmetric FIR filter, whereas the latter includes a number of feature extraction steps: zero-crossing detection, peak (zero-derivative) detection, threshold adjustment and two finite state machines for executing the decision rules. Fabricated in 0.35-?m CMOS the 300-Hz processor draws only 0.83 ?W, which is favorably comparable with the prior arts. In the system tests, the input data is placed via an on-chip 10-bit SAR analog-to-digital converter, while the output data is emitted via an off-the-shelf wireless transmitter (TI CC2500) that is configurable by the processor for different data transmission modes: 1) QRS detection result, 2) raw ECG data or 3) both. Validated with all recordings from the MIT-BIH arrhythmia database, 99.31% sensitivity and 99.70% predictivity are achieved. Mode 1 with solely the result of QRS detection exhibits 6× reduction of system power over modes 2 and 3. PMID:23853259

Ieong, Chio-In; Mak, Pui-In; Lam, Chi-Pang; Dong, Cheng; Vai, Mang-I; Mak, Peng-Un; Pun, Sio-Hang; Wan, Feng; Martins, Rui P

2012-12-01

65

Development of an automated updated Selvester QRS scoring system using SWT-based QRS fractionation detection and classification.  

PubMed

The Selvester score is an effective means for estimating the extent of myocardial scar in a patient from low-cost ECG recordings. Automation of such a system is deemed to help implementing low-cost high-volume screening mechanisms of scar in the primary care. This paper describes, for the first time to the best of our knowledge, an automated implementation of the updated Selvester scoring system for that purpose, where fractionated QRS morphologies and patterns are identified and classified using a novel stationary wavelet transform (SWT)-based fractionation detection algorithm. This stage informs the two principal steps of the updated Selvester scoring scheme--the confounder classification and the point awarding rules. The complete system is validated on 51 ECG records of patients detected with ischemic heart disease. Validation has been carried out using manually detected confounder classes and computation of the actual score by expert cardiologists as the ground truth. Our results show that as a stand-alone system it is able to classify different confounders with 94.1% accuracy whereas it exhibits 94% accuracy in computing the actual score. When coupled with our previously proposed automated ECG delineation algorithm, that provides the input ECG parameters, the overall system shows 90% accuracy in confounder classification and 92% accuracy in computing the actual score and thereby showing comparable performance to the stand-alone system proposed here, with the added advantage of complete automated analysis without any human intervention. PMID:24403417

Bono, Valentina; Mazomenos, Evangelos B; Chen, Taihai; Rosengarten, James A; Acharyya, Amit; Maharatna, Koushik; Morgan, John M; Curzen, Nick

2014-01-01

66

[ECG QRS signal detection and control system design of ventricular assist device].  

PubMed

In order to achieve auxiliary timing of ventricular assisting device to automatically track the ECG signals, we designed a set of ECG acquisition circuit in our study for the first time. Then we carried out ECG acquisition, smoothing filter and QRS detection on the LabVIEW. With the QRS signal as a benchmark, the control system immediately triggered ventricular assisting device to trigger the heart to contract for ejection for about 300 ms, and then to assist to make it relax. The practical effects of the experiment proved that ECG acquisition circuit had the feature of strong anti-interference, and control system had no false QRS detection and no false triggering of assist device. This achieves the auxiliary timing which could automatically track the ECG signal. PMID:23865330

Liao, Huogen; Yang, Ming; Zhuang, Xiaoqi; Huang, Huan

2013-06-01

67

Simultaneous QRS detection and feature extraction using simple matched filter basis functions  

Microsoft Academic Search

A simple, easily implemented method is presented for extracting from an electrocardiogram (ECG) features describing QRS morphology. Tests using the American Heart Association (AHA) database indicate that these features are successful at enabling premature ventricular contractions (PVCs) to be associated with other PVCs on the basis of morphology 99% of the time. The good performance of this method suggests that

D. T. Kaplan

1990-01-01

68

PILOTING REAL-TIME QRS DETECTION ALGORITHMS IN VARIABLE F. Portet and G. Carrault  

E-print Network

.portet@irisa.fr Abstract: This paper presents a cardiac arrhythmi- a medical monitoring system that can modify and change the current context, to pilot QRS detection algo- rithms in order to reduce the number of errors. The algorithms are piloted according to a set of piloting rules acquired by statistical analysis. Results

Paris-Sud XI, Université de

69

Fast QRS Detection with an Optimized Knowledge-Based Method: Evaluation on 11 Standard ECG Databases  

PubMed Central

The current state-of-the-art in automatic QRS detection methods show high robustness and almost negligible error rates. In return, the methods are usually based on machine-learning approaches that require sufficient computational resources. However, simple-fast methods can also achieve high detection rates. There is a need to develop numerically efficient algorithms to accommodate the new trend towards battery-driven ECG devices and to analyze long-term recorded signals in a time-efficient manner. A typical QRS detection method has been reduced to a basic approach consisting of two moving averages that are calibrated by a knowledge base using only two parameters. In contrast to high-accuracy methods, the proposed method can be easily implemented in a digital filter design. PMID:24066054

Elgendi, Mohamed

2013-01-01

70

Fast QRS detection with an optimized knowledge-based method: evaluation on 11 standard ECG databases.  

PubMed

The current state-of-the-art in automatic QRS detection methods show high robustness and almost negligible error rates. In return, the methods are usually based on machine-learning approaches that require sufficient computational resources. However, simple-fast methods can also achieve high detection rates. There is a need to develop numerically efficient algorithms to accommodate the new trend towards battery-driven ECG devices and to analyze long-term recorded signals in a time-efficient manner. A typical QRS detection method has been reduced to a basic approach consisting of two moving averages that are calibrated by a knowledge base using only two parameters. In contrast to high-accuracy methods, the proposed method can be easily implemented in a digital filter design. PMID:24066054

Elgendi, Mohamed

2013-01-01

71

Changes of QRS axis in transient myocardial ischaemia induced by percutaneous transluminal coronary angioplasty.  

PubMed

The QRS axis of 130 consecutive patients with coronary artery disease undergoing percutaneous transluminal coronary angioplasty (PTCA) were measured before balloon inflation and just before balloon deflation. Patients were divided into two groups. Group A (103) had angina pectoris and/or non-transmural old myocardial infarction with no abnormal Q waves; group B (27) had an old transmural myocardial infarction with abnormal Q waves. In group A, the QRS axis had significantly shifted to the left in patients with left anterior descending artery (LAD) occlusion (from 68.0 +/- 42.7 degrees to 40.2 +/- 44.6 degrees, P < 0.001); however in those patients without involvement of the major septal branch, significant axis changes were not observed (from 53.6 +/- 34.1 degrees to 49.8 +/- 33.1 degrees). When the right coronary artery (RCA) was occluded in group A, the QRS axis shifted to the right significantly (from 63.2 +/- 40.0 degrees to 89.8 +/- 30.1 degrees. P < 0.01); during left circumflex artery (LCX) occlusion, no significant axis shift was observed. In group B, no significant axis shift was observed either in patients with occlusion of the LAD or the RCA. It is concluded that transient left axis deviation reflects an obstructive lesion of the proximal portion of the LAD with involvement of the major septal branch, and transient right axis deviation reflects an obstructive lesion of the RCA. PMID:7821318

Shirota, K; Ogino, K; Hoshio, A; Kasahara, T; Kotake, H; Endo, S; Mashiba, H

1994-10-01

72

Very low frequency modulation in QRS slopes and its relation with respiration and heart rate variability during hemodialysis.  

PubMed

In this work, we study the very low frequency (VLF) modulation (range 0.01-0.03 Hz) in QRS slopes, heart rate variability (HRV) and ECG-derived respiration in hemodialysis patients. First, the relation between QRS slopes and HRV in the VLF band is measured using ordinary coherence. Then, partial coherence is used to measure the former relationship once the effect related to respiration is removed. Ordinary coherence values above a statistical threshold revealed linear relationship between VLF modulation in QRS slopes and HRV in about 10% of analyzed segments, with mean ± SD values of 0.79 ± 0.07 for upward slope and 0.77 ± 0.06 for downward slope. For these segments, partial coherence values drop below the threshold for 64% of the cases for upward slope and 76% for downward slope, suggesting that the origin of the VLF modulation in QRS slopes is mainly driven by respiration or linearly related to it. In the rest of the cases, partial coherence values dropped with respect to ordinary coherence from 0.89 to 0.77 for upward slope and from 0.86 to 0.75 for downward slope, suggesting that other ANS effects non-linearly related to respiration also contribute to the VLF modulation in QRS slopes. PMID:24110948

Hernando, David; Alcaine, Alejandro; Laguna, Pablo; Pueyo, Esther; Bailon, Raquel

2013-01-01

73

Quantifying QRS changes during myocardial ischemia: Insights from high frequency electrocardiography.  

PubMed

Over four decades of high frequency electrocardiography research have provided a body of knowledge about QRS changes during myocardial ischemia, and the techniques to measure and quantify them. High-frequency QRS (HFQRS) components, being closely related to the pattern of ventricular depolarization, carry valuable clinical information. Changes in HFQRS amplitude and morphology have been shown to be sensitive diagnostic markers of myocardial ischemia, often superior to measures of ST-T segment changes. Clinical studies in patients undergoing exercise testing have consistently demonstrated the incremental diagnostic value of HFQRS analysis in detection of demand ischemia. In 6 studies that evaluated the HyperQ™ technology, the average sensitivity and specificity of HFQRS analysis were 75%±6% and 80%±6%, respectively, compared to average sensitivity 48%±16% and average specificity 70%±15% of ST segment analysis. In patients with acute supply ischemia, recent studies characterized and quantified the ischemic HFQRS patterns. HFQRS morphology index was found to be higher in patients with acute coronary syndrome (ACS), compared to non-ischemic, with good sensitivity in patients without ST elevation. These research findings may be translated into commercially-available ECG systems and be used in clinical practice for improved diagnosis and monitoring of myocardial ischemia. PMID:24795285

Amit, Guy; Granot, Yair; Abboud, Shimon

2014-01-01

74

A robust physiology-based source separation method for QRS detection in low amplitude fetal ECG recordings.  

PubMed

The use of the non-invasively obtained fetal electrocardiogram (ECG) in fetal monitoring is complicated by the low signal-to-noise ratio (SNR) of ECG signals. Even after removal of the predominant interference (i.e. the maternal ECG), the SNR is generally too low for medical diagnostics, and hence additional signal processing is still required. To this end, several methods for exploiting the spatial correlation of multi-channel fetal ECG recordings from the maternal abdomen have been proposed in the literature, of which principal component analysis (PCA) and independent component analysis (ICA) are the most prominent. Both PCA and ICA, however, suffer from the drawback that they are blind source separation (BSS) techniques and as such suboptimum in that they do not consider a priori knowledge on the abdominal electrode configuration and fetal heart activity. In this paper we propose a source separation technique that is based on the physiology of the fetal heart and on the knowledge of the electrode configuration. This technique operates by calculating the spatial fetal vectorcardiogram (VCG) and approximating the VCG for several overlayed heartbeats by an ellipse. By subsequently projecting the VCG onto the long axis of this ellipse, a source signal of the fetal ECG can be obtained. To evaluate the developed technique, its performance is compared to that of both PCA and ICA and to that of augmented versions of these techniques (aPCA and aICA; PCA and ICA applied on preprocessed signals) in generating a fetal ECG source signal with enhanced SNR that can be used to detect fetal QRS complexes. The evaluation shows that the developed source separation technique performs slightly better than aPCA and aICA and outperforms PCA and ICA and has the main advantage that, with respect to aPCA/PCA and aICA/ICA, it performs more robustly. This advantage renders it favorable for employment in automated, real-time fetal monitoring applications. PMID:20530846

Vullings, R; Peters, C H L; Hermans, M J M; Wijn, P F F; Oei, S G; Bergmans, J W M

2010-07-01

75

A ROBUST METHOD FOR QRS DETECTION BASED ON MODIFIED P-SPECTRUM , and K. J. Ray Liu2  

E-print Network

of useful information for diag- nosis, i.e. heart rate, heart rate variability, etc. The extraction signals, the time interval between consecutive heart beats is not a constant, because of the heart rate on the mod- i ed p-spectrum to detect heart beats in ECG signals, which is also referred as QRS detection

Liu, K. J. Ray

76

Fragmented QRS on surface electrocardiogram is not a reliable predictor of myocardial scar, angiographic coronary disease or long term adverse outcomes  

PubMed Central

Purpose Conflicting evidence remains regarding the value of fragmented QRS (fQRS) on surface electrocardiogram (EKG). We present the 5-year outcome of patients with fQRS on EKG and its correlation to SPECT and coronary angiography (CA). Methods We retrospectively studied EKG’s in 248 consecutive patients undergoing SPECT and CA with known or suspected coronary artery disease (CAD). The presence of fQRS or Q waves in two contiguous EKG leads was correlated with major coronary artery distributions on SPECT and cath. Patients with bundle-branch block, paced-rhythm or absence of EKG within one month of SPECT were excluded. The final EKG data for 238 patients were analyzed and compared with myocardial scar on SPECT and the presence of significant (>50%) coronary stenosis on CA. Predictors of MACE (death, MI, heart failure) were evaluated. Freedom from all-cause mortality was assessed by Kaplan-Meier analysis. Results Of 238 patients, no significant difference was noted in the presence of scar on SPECT in fQRS (3/77; 3.8%) versus no fQRS (11/161; 6.8%) (P=0.56); or CA based CAD (55/77; 71% fQRS) and no fQRS (99/161, 61.4%) (P=0.20). EKG Q wave presence was similar in both groups: (12/77; 15.5% fQRS), (17/161; 10.5% no fQRS) (P=0.3). Patients with CA based significant LAD disease were 3.680 times more likely to have fQRS (P=0.04), however, fQRS was not significantly associated with MACE (P=0.92) or all-cause mortality (P=0.93). Conclusions This study does not support routine assessment of fQRS on surface EKG as a reliable predictor of SPECT myocardial scar, MACE or all-cause mortality over a long period of follow-up. PMID:25276613

Wang, Dee Dee; Tibrewala, Amit; Nguygen, Phuc; Swadia, Tanmay; Jacobsen, Gordon; Khan, Arfaat

2014-01-01

77

When Deriving the Spatial QRS-T Angle from the 12-lead ECG, which Transform is More Frank: Regression or Inverse Dower?  

NASA Technical Reports Server (NTRS)

Our primary objective was to ascertain which commonly used 12-to-Frank-lead transformation yields spatial QRS-T angle values closest to those obtained from simultaneously collected true Frank-lead recordings. Simultaneous 12-lead and Frank XYZ-lead recordings were analyzed for 100 post-myocardial infarction patients and 50 controls. Relative agreement, with true Frank-lead results, of 12-to-Frank-lead transformed results for the spatial QRS-T angle using Kors regression versus inverse Dower was assessed via ANOVA, Lin s concordance and Bland-Altman plots. Spatial QRS-T angles from the true Frank leads were not significantly different than those derived from the Kors regression-related transformation but were significantly smaller than those derived from the inverse Dower-related transformation (P less than 0.001). Independent of method, spatial mean QRS-T angles were also always significantly larger than spatial maximum (peaks) QRS-T angles. Spatial QRS-T angles are best approximated by regression-related transforms. Spatial mean and spatial peaks QRS-T angles should also not be used interchangeably.

Schlegel, Todd T.; Cortez, Daniel

2010-01-01

78

Duration tuning across vertebrates.  

PubMed

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

Aubie, Brandon; Sayegh, Riziq; Faure, Paul A

2012-05-01

79

Duration, convexity and immunisation  

E-print Network

or effective duration (i) = - d(ln(V )) di = - 1 V dV di . (b) discounted mean term (DMT) or MacAuley duration outflows. Example 78 DMT of an n-year coupon-paying bond, annual coupons of D, redemption proceeds of R the special case of a zero-coupon bond of duration n, which has DMT n. Note however, that it is the Mac

Winkel, Matthias

80

Heat Storage Duration.  

National Technical Information Service (NTIS)

Both the amount and duration of heat storage in massive elements of a passive building are investigated. Data taken for one full winter in the Balcomb solar home are analyzed with the aid of sub-system simulation models. Heat storage duration is tallied i...

J. D. Balcomb

1981-01-01

81

Electrocradiographic Qrs Axis, Q Wave and T-wave Changes in 2nd and 3rd Trimester of Normal Pregnancy  

PubMed Central

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

S., Chandrasekharappa; Brid, S.V

2014-01-01

82

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)

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.

Ghatak, Arundhuti; Basu, Asish R.; Wakabayashi, John

2013-09-01

83

Quantitative analysis of QRS detection algorithms based on the first derivative of the ECG.  

PubMed

Accurate processing of electrocardiogram (ECG) signals requires a sensitive and robust QRS detection method. In this study, three methods are quantitatively compared using a similar algorithm structure but applying different transforms to the differentiated ECG. The three transforms used are the Hilbert transformer, the squaring function, and a second discrete derivative stage. The first two have been widely used in ECG and heart rate variability analysis while the second derivative method aims to explain the success of the Hilbert transform. The algorithms were compared in terms of the number of false positive and false negative detections produced for records of the MIT/BIH Arrhythmia Database. The Hilbert transformer and the squaring function both produced a sensitivity and positive predictivity of over 99%, though the squaring function had a lower overall detection error rate. The second derivative resulted in the highest overall detection error rate. Different algorithms performed better for diverse ECG characteristics; suggesting that an algorithm can be specified for different recordings, the algorithms can be combined based on each one's characteristics to determine a new more accurate method, or an additional detection stage can be added to reduce the number of false negatives. PMID:17946480

Arzeno, Natalia M; Poon, Chi-Sang; Deng, Zhi-De

2006-01-01

84

The relationship of QRS morphology and mechanical dyssynchrony to long-term outcome following cardiac resynchronization therapy  

PubMed Central

Aims Because benefits of cardiac resynchronization therapy (CRT) appear to be less favourable in non-left bundle branch block (LBBB) patients, this prospective longitudinal study tested the hypothesis that QRS morphology and echocardiographic mechanical dyssynchrony were associated with long-term outcome after CRT. Methods and results Two-hundred and seventy-eight consecutive New York Heart Association class III and IV CRT patients with QRS ?120 ms and ejection fraction ?35% were studied. The pre-specified primary endpoint was death, heart transplant, or left ventricular assist device over 4 years. Dyssynchrony assessed before CRT included interventricular mechanical delay (IVMD) and speckle-tracking radial strain using pre-specified cut-offs for each. Of 254 with baseline quantitative echocardiographic data available, 128 had LBBB, 81 had intraventricular conduction delay (IVCD), and 45 had right bundle branch block (RBBB). Radial dyssynchrony was observed in 85% of the patients with LBBB, 59% with IVCD*, and 40% with RBBB* (*P < 0.01 vs. LBBB). Of 248 (98%) with follow-up, LBBB patients had a significantly more favourable long-term survival than non-LBBB patients. However, non-LBBB patients with dyssynchrony had a more favourable event-free survival than those without dyssynchrony: radial dyssynchrony hazard ratio 2.6, 95% confidence interval (CI) 1.47–4.53 (P = 0.0008) and IVMD hazard ratio 4.9, 95% CI 2.60–9.16 (P = 0.0007). Right bundle branch block patients who lacked dyssynchrony had the least favourable outcome. Conclusion Non-LBBB patients with dyssynchrony had a more favourable long-term survival than non-LBBB patients who lacked dyssynchrony. Mechanical dyssynchrony and QRS morphology are associated with outcome following CRT. PMID:22351700

Hara, Hideyuki; Oyenuga, Olusegun A.; Tanaka, Hidekazu; Adelstein, Evan C.; Onishi, Toshinari; McNamara, Dennis M.; Schwartzman, David; Saba, Samir; Gorcsan, John

2012-01-01

85

Duration response measurement error  

Microsoft Academic Search

The impact of response measurement error in duration data is investigated using small parameter asymptotic approximations and compared with the effect of hazard function heterogeneity. The approximations lead to a specification test to detect measurement error which is shown to be related to the class of Information Matrix tests. It is shown that in a commonly used class of models

Andrew Chesher; Montezuma Dumangane; Richard J. Smith

2002-01-01

86

Low complexity algorithms for heart rate and epileptic seizure detection  

Microsoft Academic Search

Algorithm design for low power platforms is constrained by memory and computational limitations, and real-world applications demand robust performance. This paper presents two algorithms that were designed with the view that simplicity can translate to robustness. The first algorithm processes electrocardiogram (ECG) signals to detect QRS complexes reliably in the presence of significant noise. The second algorithm is a low-cost

Sourabh Ravindran; Randy Cole

2009-01-01

87

Impacts of Coulomb Interactions on the Magnetic Responses of Excitonic Complexes in Single Semiconductor Nanostructures  

PubMed Central

We report on the diamagnetic responses of different exciton complexes in single InAs/GaAs self-assembled quantum dots (QDs) and quantum rings (QRs). For QDs, the imbalanced magnetic responses of inter-particle Coulomb interactions play a crucial role in the diamagnetic shifts of excitons (X), biexcitons (XX), and positive trions (X?). For negative trions (X?) in QDs, anomalous magnetic responses are observed, which cannot be described by the conventional quadratic energy shift with the magnetic field. The anomalous behavior is attributed to the apparent change in the electron wave function extent after photon emission due to the strong Coulomb attraction by the hole in its initial state. In QRs, the diamagnetic responses of X and XX also show different behaviors. Unlike QDs, the diamagnetic shift of XX in QRs is considerably larger than that of X. The inherent structural asymmetry combined with the inter-particle Coulomb interactions makes the wave function distribution of XX very different from that of X in QRs. Our results suggest that the phase coherence of XX in QRs may survive from the wave function localization due to the structural asymmetry or imperfections. PMID:20672111

2010-01-01

88

Impacts of coulomb interactions on the magnetic responses of excitonic complexes in single semiconductor nanostructures.  

PubMed

We report on the diamagnetic responses of different exciton complexes in single InAs/GaAs self-assembled quantum dots (QDs) and quantum rings (QRs). For QDs, the imbalanced magnetic responses of inter-particle Coulomb interactions play a crucial role in the diamagnetic shifts of excitons (X), biexcitons (XX), and positive trions (X-). For negative trions (X-) in QDs, anomalous magnetic responses are observed, which cannot be described by the conventional quadratic energy shift with the magnetic field. The anomalous behavior is attributed to the apparent change in the electron wave function extent after photon emission due to the strong Coulomb attraction by the hole in its initial state. In QRs, the diamagnetic responses of X and XX also show different behaviors. Unlike QDs, the diamagnetic shift of XX in QRs is considerably larger than that of X. The inherent structural asymmetry combined with the inter-particle Coulomb interactions makes the wave function distribution of XX very different from that of X in QRs. Our results suggest that the phase coherence of XX in QRs may survive from the wave function localization due to the structural asymmetry or imperfections. PMID:20672111

Chang, Wen-Hao; Lin, Chia-Hsien; Fu, Ying-Jhe; Lin, Ta-Chun; Lin, Hsuan; Cheng, Shuen-Jen; Lin, Sheng-Di; Lee, Chien-Ping

2010-01-01

89

Long duration flights management  

NASA Astrophysics Data System (ADS)

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.

Sosa-Sesma, Sergio; Letrenne, Gérard; Spel, Martin; Charbonnier, Jean-Marc

90

Uncertainty and Labor Contract Durations  

Microsoft Academic Search

This paper provides an empirical investigation into the relationship between uncertainty and ex ante U.S. labor contract durations over the period 1970 to 1995. Using a structural identification of aggregate demand and aggregate supply shocks, we find that desired contract durations are shorter during periods of heightened nominal or real uncertainty. This evidence supports the view that labor contract durations

Robert Rich; Joseph Tracy

2004-01-01

91

Conf Proc IEEE Eng Med Biol Soc . Author manuscript Analysis of the QRS complex for apnea-bradycardia characterization in  

E-print Network

identified as a predisposing factor to sudden-death syndrome in newborns .[1 ] [2 ] Furthermore database Data were obtained from 32 premature infants, who presented more than one bradycardia per hour and, the median age was 31.2 weeks and

Paris-Sud XI, Université de

92

Long duration ash probe  

DOEpatents

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 sootblowing 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.

Hurley, John P. (Grand Forks, ND); McCollor, Don P. (Grand Forks, ND); Selle, Stanley J. (Grand Forks, MN)

1994-01-01

93

Long duration ash probe  

DOEpatents

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.

Hurley, J.P.; McCollor, D.P.; Selle, S.J.

1994-07-26

94

Uncertainty and Labor Contract Durations  

Microsoft Academic Search

This paper provides an empirical investigation into the relationship between ex ante U.S. labor contract durations and uncertainty over the period 1970 to 1995. We construct measures of inflation uncertainty as well as aggregate nominal and real uncertainty. The results not only corroborate previous findings of an inverse relationship between contract duration and inflation uncertainty, but document that this relationship

Robert Rich; Joseph Tracy

2000-01-01

95

Estimating the duration of speciation from phylogenies.  

PubMed

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

Etienne, Rampal S; Morlon, Hélène; Lambert, Amaury

2014-08-01

96

Wellens syndrome associated with prominent anterior QRS forces: an expression of left septal fascicular block?  

Microsoft Academic Search

Wellens syndrome is a clinical-electrocardiographic entity also referred to as left anterior descending (LAD) coronary T-wave syndrome or acute coronary T-wave syndrome. It is a complex of symptoms and signals indicating the existence of an undesirable condition secondary to critical high-grade proximal stenosis of the LAD coronary artery characterized by the association of prior history of acute coronary syndrome with

Andrés Ricardo Pérez Riera; Celso Ferreira; Celso Ferreira Filho; Sergio Dubner; Edgardo Schapachnik; Augusto H. Uchida; Paulo Moffa; Li Zhang; Antoni Bayes de Luna

2008-01-01

97

Clustering ECG complexes using Hermite functions and self-organizing maps  

Microsoft Academic Search

:An integrated method for identifying and classifying ECG complexes in the MIT-BIH ArrhythmiaDatabase is presented. The QRS complexes are extracted and the RR intervals are calculatedin an autonomous way. Each complex is subsequently decomposed into Hermite basis functions,from which the resulting coefficients and widths are used to represent the beats. By means ofthis representation, unsupervised self-organizing neural networks are employed

M. Lagerholm; C. Peterson; G. Braccini; L. Edenbrandt; L. Sornmo

2000-01-01

98

ECG waves and features extraction using Wavelet Multi-Resolution Analysis  

Microsoft Academic Search

In this paper, using Wavelet Multi-Resolution Analysis, are extracted QRS complex and T wave and some feature of electrocardiographic (ECG) signal acquired in order to obtain the accurate time localization. The results consist in representing the amplitude and duration of QRS complex, the Heart Rate Variability's (HRV) representation and also the characteristics of T wave representation.

Narcis Adochiei; Valeriu David; Felix Adochiei; Ioan Tudosa

2011-01-01

99

Wellens syndrome associated with prominent anterior QRS forces: an expression of left septal fascicular block?  

PubMed

Wellens syndrome is a clinical-electrocardiographic entity also referred to as left anterior descending (LAD) coronary T-wave syndrome or acute coronary T-wave syndrome. It is a complex of symptoms and signals indicating the existence of an undesirable condition secondary to critical high-grade proximal stenosis of the LAD coronary artery characterized by the association of prior history of acute coronary syndrome with little or no elevation of markers of myocardial damage (unstable angina) and characteristic electrocardiographic changes consistent with subepicardial anterior ischemic pattern (persistently symmetrical, deep negative and broad-based T waves) or plus-minus T waves with inversion of the terminal portion in the LAD coronary artery territory (V1 through V5 or V6). We present a case of a variant of Wellens syndrome that reveals association and, transitorily, the criteria described in literature for left septal fascicular block. PMID:18649894

Riera, Andrés Ricardo Pérez; Ferreira, Celso; Ferreira Filho, Celso; Dubner, Sergio; Schapachnik, Edgardo; Uchida, Augusto H; Moffa, Paulo; Zhang, Li; de Luna, Antoni Bayes

2008-01-01

100

Extended Duration Orbiter Medical Project  

NASA Technical Reports Server (NTRS)

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.

Leach, C. S.; Pool, S. L.; Sawin, C. F.; Nicogossian, A. E.

1990-01-01

101

Curricular internship Timing and Duration  

E-print Network

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

Krause, Rolf

102

JACEE long duration balloon flights  

SciTech Connect

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.

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,

1989-01-01

103

Duration of Life of Woodlice  

Microsoft Academic Search

SOME little time ago I published a note on the duration of life of certain species of woodlice1 which had been studied by Major Stanley S. Flower and me., and it was there recorded that Major Flower had kept a specimen of Oniscus asellus Linn, (born in captivity) for approximately 4 years 8 months and 28 days or possibly 4

Walteb E. Collinge

1945-01-01

104

Time plane ECG feature extraction using Hilbert transform, variable threshold and slope reversal approach  

Microsoft Academic Search

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

S. K. Mukhopadhyay; M. Mitra; S. Mitra

2011-01-01

105

Sleep duration, asthma and obesity  

PubMed Central

Background Obesity is more prevalent in asthmatics. Short sleep duration is a novel risk factor for obesity in general populations. Objective We tested the association of sleep duration and asthma characteristics with obesity. Methods Adults at tertiary clinics were surveyed on asthma symptoms and habitual sleep duration. Medical records were used to assess asthma severity step (1-4), extract height and weight, current medications and diagnosed comorbid conditions. BMI?30 kg/m2 defined obesity. Habitual sleep was categorized as <6 (very short), 6 to <7h (short), 7-8h (normal), >8 to ?9h (long) and >9h (very long). Inhaled corticosteroid doses were categorized as low, moderate and high. Results Among 611 participants (mean BMI 30±8), 249 (41%) were obese. After adjustment for covariates, obesity was associated with short and very long sleep: as compared to normal sleepers, the odds of being obese were on average 66% higher ([95% Confidence Interval: 1.07-2.57], p=0.02) among short and 124% higher ([1.08-1.65], p=0.03) among very long sleepers, and the association with very short sleep approached significance (1.74 [0.96-3.14], p=0.06). Obesity was also significantly related to highest asthma step (1.87 [1.09-3.21], p=0.02) and psychopathology (1.64 [1.08-2.48], p=0.02), and a trend was seen with high dose inhaled corticosteroids (1.82 [0.93-3.56], p=0.08). Conclusions Obesity in asthmatics is associated with shorter and very long sleep duration, worse asthma severity, psychopathology, and high dose inhaled corticosteroids. Although this cross-sectional study cannot prove causality, we speculate that further investigation of sleep may provide new opportunities to reduce the rising prevalence of obesity among asthmatics. PMID:23923994

Teodorescu, Mihaela; Polomis, David A.; Gangnon, Ronald E.; Consens, Flavia B.; Chervin, Ronald D.; Teodorescu, Mihai C.

2013-01-01

106

Preexisting hypoxia is associated with a delayed but more sustained rise in T/QRS ratio during prolonged umbilical cord occlusion in near-term fetal sheep.  

PubMed

There is limited information about whether preexisting fetal hypoxia alters hemodynamic responses and changes in T/QRS ratio and ST waveform shape during subsequent severe asphyxia. Chronically instrumented near-term sheep fetuses (124 +/- 1 days) were identified as either normoxic Pa(O(2)) > 17 mmHg (n = 9) or hypoxic Pa(O(2)) < or = 17 mmHg (n = 5); then they received complete occlusion of the umbilical cord for 15 min. Umbilical cord occlusion led to sustained bradycardia, severe acidosis, and transient hypertension followed by profound hypotension in both groups. Preexisting hypoxia did not affect changes in mean arterial blood pressure but was associated with a more rapid initial fall in femoral blood flow and vascular conductance and with transiently higher fetal heart rate at 2 min and from 9 to 11 min of occlusion compared with previously normoxic fetuses. Occlusion was associated with a significant but transient rise in T/QRS ratio; preexisting hypoxia was associated with a significant delay in this rise (maxima 3.7 +/- 0.4 vs. 6.2 +/- 0.5 min), but a slower rate of fall. There was a similar elevation in troponin-T levels 6 h after occlusion in the two groups [median (range) 0.43 (0.08, 1.32) vs. 0.55 (0.16, 2.32) microg/l, not significant]. In conclusion, mild preexisting hypoxia in normally grown singleton fetal sheep is associated with more rapid centralization of circulation after umbilical cord occlusion and delayed elevation of the ST waveform and slower fall, suggesting that chronic hypoxia alters myocardial dynamics during asphyxia. PMID:17652358

Wibbens, Bert; Bennet, Laura; Westgate, Jenny A; De Haan, Harmen H; Wassink, Guido; Gunn, Alistair J

2007-09-01

107

Planning with Durative Actions in Stochastic Domains  

Microsoft Academic Search

Probabilistic planning problems are typically modeled as a Markov Decision Process (MDP). MDPs, while an otherwise expressive model, allow only for sequential, non-durative actions. This poses severe restrictions in modeling and solving a real world planning problem. We extend the MDP model to incorporate — 1) simultaneous action execution, 2) durative actions, and 3) stochas- tic durations. We develop several

Mausam; Daniel S. Weld

2008-01-01

108

Duration Sensitivity Depends on Stimulus Familiarity  

Microsoft Academic Search

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 be able to evaluate the duration of stimuli in isolation, however,

Carey K. Morewedge; Karim S. Kassam; Christopher K. Hsee; Eugene M. Caruso

2009-01-01

109

COMPLEX TRAUMA, COMPLEX REACTIONS: ASSESSMENT AND TREATMENT  

Microsoft Academic Search

Complex trauma occurs repeatedly and escalates over its duration. In families, it is exemplified by domestic violence and child abuse and in other situations by war, prisoner of war or refugee status, and human trafficking. Complex trauma also refers to situations such as acute\\/chronic illness that requires intensive medical intervention or a single traumatic event that is calamitous. Complex trauma

Christine A. Courtois

2004-01-01

110

Complex Trauma, Complex Reactions: Assessment and Treatment  

Microsoft Academic Search

Complex trauma occurs repeatedly and escalates over its duration. In families, it is exemplified by domestic violence and child abuse and in other situations by war, prisoner of war or refugee status, and human trafficking. Complex trauma also refers to situations such as acute\\/chronic illness that requires intensive medical intervention or a single traumatic event that is calamitous. Complex trauma

Christine A. Courtois

2008-01-01

111

Extended Duration Orbiter Medical Project  

NASA Technical Reports Server (NTRS)

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.

Sawin, Charles F. (Editor); Taylor, Gerald R. (Editor); Smith, Wanda L. (Editor); Brown, J. Travis (Technical Monitor)

1999-01-01

112

The Case for Durative Actions: A Commentary on PDDL2.1  

NASA Technical Reports Server (NTRS)

The addition of durative actions to PDDL2.1 sparked some controversy. Fox and Long argued that actions should be considered as instantaneous, but can start and stop processes. Ultimately, a limited notion of durative actions was incorporated into the language. I argue that this notion is impoverished, and that the underlying philosophical position of regarding durative actions as being a shorthand for a start action, process, and stop action ignores the realities of modelling and execution for complex systems.

Smith, David E.

2003-01-01

113

Training for long duration space missions  

NASA Technical Reports Server (NTRS)

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.

Goldberg, Joseph H.

1987-01-01

114

Health care delivery system for long duration manned space operations  

NASA Technical Reports Server (NTRS)

Specific requirements for medical support of a long-duration manned facility in a low earth orbit derive from inflight medical experience, projected medical scenarios, mission related spacecraft and environmental hazards, health maintenance, and preventive medicine. A sequential buildup of medical capabilities tailored to increasing mission complexity is proposed. The space station health maintenance facility must provide preventive, diagnostic, and therapeutic medical support as immediate rescue capability may not exist.

Logan, J. S.; Shulman, E. L.; Johnson, P. C.

1983-01-01

115

Incorporating Duration Information in Activity Recognition  

NASA Astrophysics Data System (ADS)

Activity recognition has become a key issue in smart home environments. The problem involves learning high level activities from low level sensor data. Activity recognition can depend on several variables; one such variable is duration of engagement with sensorised items or duration of intervals between sensor activations that can provide useful information about personal behaviour. In this paper a probabilistic learning algorithm is proposed that incorporates episode, time and duration information to determine inhabitant identity and the activity being undertaken from low level sensor data. Our results verify that incorporating duration information consistently improves the accuracy.

Chaurasia, Priyanka; Scotney, Bryan; McClean, Sally; Zhang, Shuai; Nugent, Chris

116

Repair of Electronics for Long Duration Spaceflight  

NASA Technical Reports Server (NTRS)

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.

Pettegrew, Richard D.; Easton, John; Struk, Peter

2007-01-01

117

Sleep duration and personality in Croatian twins.  

PubMed

The objective of this study was to examine which genetic and environmental influences contribute to individual differences in sleep duration in a sample of Croatian adolescent/early adult twins, as well as to investigate the relationship between personality and sleep duration. Participants included 339 twin pairs (105 monozygotic and 234 dizygotic) aged between 15 and 22 years. They reported on their average sleep duration and personality. The broad heritability estimate (additive and non-additive genetic influences) for sleep duration was 0.63, while personality estimates ranged between 0.47 and 0.62. Significant negative phenotypic associations with neuroticism and openness were mainly genetically mediated 100 and 80%, respectively. Only 6% of the sleep duration variance was explained by genetic influences shared with neuroticism and openness. In regression analysis, age, gender and five personality traits explained 5% of sleep duration variance, with neuroticism and openness as significant predictors. Comparison of short, moderate and long sleepers showed that participants in the short sleepers group had significantly higher neuroticism scores than groups of moderate and long sleepers, as well as a significantly higher openness score than the group of long sleepers. This indicates that personality traits of neuroticism and openness contribute to the prediction of sleep duration due to overlapping genetic influences that contribute to both these personality traits and sleep duration. However, as phenotypic overlap of personality and sleep duration is relatively weak, heritability of sleep duration is not only related to individual differences in personality traits, so future research needs to examine other phenotypic correlates of sleep duration. PMID:24635510

Butkovic, Ana; Vukasovic, Tena; Bratko, Denis

2014-04-01

118

Ischemic Ventricular Tachycardia Presenting as a Narrow Complex Tachycardia  

PubMed Central

This report describes a patient presenting with a narrow complex tachycardia in the context of prior myocardial infarction and impaired ventricular function. Electrophysiological studies confirmed ventricular tachycardia and activation and entrainment mapping demonstrated a critical isthmus within an area of scar involving the His-Purkinje system accounting for the narrow QRS morphology. This very rare case shares some similarities with upper septal ventricular tachycardia seen in patients with structurally normal hearts, but to our knowledge has not been seen previously in patients with ischemic heart disease. PMID:25057222

Page, Stephen P; Watts, Troy; Yeo, Wee Tiong; Mehul, Dhinoja

2014-01-01

119

Stimulus Intensity and the Perception of Duration  

ERIC Educational Resources Information Center

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 stimuli…

Matthews, William J.; Stewart, Neil; Wearden, John H.

2011-01-01

120

Duration-specific marital fertility in Egypt.  

PubMed

Because of the discovery of substantial underreporting of births, deaths, marriages, and divorces in Egypt, the original report of the Committee on Population and Demography on duration-secific fertility rates of married women in Egypt was modified by using estimated calculations of these vital statistics. The original report involved the calculation of duration-specific fertility rates of married women in Egypt by first estimating the number of currently married women at each duration (by single years of duration under duration 5, and by 5-year intervals of duration up to duration 20). The calculation required data on the annual number of marriages and on the number of divorces each year, classified by duration of marriage, and estimated of the number of deaths of married persons of each sex by duration of marriage. From these data, it is possible to estimate at each date the number of marriages still intact of those that took place 0-1, 1-2, 2-3, 3-4, 4-5, 5-10, 10-15, and 15-20 years earlier. Deficits in the recorded number of marriages cause implausible variations in duration-specific fertility. It is important to discover the extent to which the recent apparent increase in birthrate is genuine, and the extent to which it is the result of improved registration. Factors causing an increase in fertility could be increase in the fraction of the population of childbearing age that is currently married; reduction in the interbirth intervals in the early years of marriage as a result of shorter average period of breastfeeding; or reduction in the practice of contraception or in the effectiveness of such practice. Duration-specific fertility rates were recalculated for 1966-79 by estimating the number of currently married women at each duration of marriage. If registered data are accurate, there was a slight increase in marital fertility after 1975 or 1976, and a large increase in 1979. The sharp rise in 1979 should not be accepted without study of registration procedures. Underregistration of births in the early 1970s was estimated at 4%. Since births are recorded by year of registration rather than year of occurrence, improved registration might include not only a more complete record of current births, but also the backlog of previously unregistered events. PMID:12266317

Coale, A J; El-atoum, S

1982-01-01

121

14 CFR 21.443 - Duration.  

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...

2010-01-01

122

Case files of the Medical Toxicology Fellowship at the Toxikon Consortium in Chicago: Cocaine-associated wide-complex dysrhythmias and cardiac arrest— treatment nuances and controversies  

Microsoft Academic Search

Conclusion  Manifestations of cocaine poisoning range widely from mild sympathomimetic overdrive to life-threatening seizures, hyperthermia,\\u000a and cardiac dysrhythmias. While supportive care, including the judicious use of benzodiazepines and cooling measures, is paramount,\\u000a the management of cocaine-associated wide-complex dysrhythmias and cardiac arrest regularly includes sodium bicarbonate boluses\\u000a in order to narrow QRS length. When confronted with refractory dysrhythmias, one must weigh the

Ejaaz A. Kalimullah; Sean M. Bryant

2008-01-01

123

Duration discrimination in the mouse ( Mus musculus )  

Microsoft Academic Search

Detection thresholds for an increment in duration of a 10-kHz pure tone were determined in the NMRI mouse using a Go\\/NoGo-procedure and the method of constant stimuli. Thresholds for reference durations of 50, 100 and 200 ms were obtained presenting the signals at a fixed level or at a level varying by ±3 dB. Thresholds were determined using signal-detection theory ( d?=1.0

Karin B. Klink; Georg M. Klump

2004-01-01

124

Strong motion duration and earthquake magnitude relationships  

SciTech Connect

Earthquake duration is the total time of ground shaking from the arrival of seismic waves until the return to ambient conditions. Much of this time is at relatively low shaking levels which have little effect on seismic structural response and on earthquake damage potential. As a result, a parameter termed ``strong motion duration`` has been defined by a number of investigators to be used for the purpose of evaluating seismic response and assessing the potential for structural damage due to earthquakes. This report presents methods for determining strong motion duration and a time history envelope function appropriate for various evaluation purposes, for earthquake magnitude and distance, and for site soil properties. There are numerous definitions of strong motion duration. For most of these definitions, empirical studies have been completed which relate duration to earthquake magnitude and distance and to site soil properties. Each of these definitions recognizes that only the portion of an earthquake record which has sufficiently high acceleration amplitude, energy content, or some other parameters significantly affects seismic response. Studies have been performed which indicate that the portion of an earthquake record in which the power (average rate of energy input) is maximum correlates most closely with potential damage to stiff nuclear power plant structures. Hence, this report will concentrate on energy based strong motion duration definitions.

Salmon, M.W.; Short, S.A. [EQE International, Inc., San Francisco, CA (United States); Kennedy, R.P. [RPK Structural Mechanics Consulting, Yorba Linda, CA (United States)

1992-06-01

125

Estimating magnitude and duration of incident delays  

SciTech Connect

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).

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

1997-11-01

126

Sleep duration, cardiovascular disease, and proinflammatory biomarkers  

PubMed Central

Habitual sleep duration has been associated with cardiometabolic disease, via several mechanistic pathways, but few have been thoroughly explored. One hypothesis is that short and/or long sleep duration is associated with a proinflammatory state, which could increase risk for cardiovascular and metabolic diseases. This hypothesis has been largely explored in the context of experimental sleep deprivation studies which have attempted to demonstrate changes in proinflammatory markers following acute sleep loss in the laboratory. Despite the controlled environment available in these studies, samples tend to lack generalization to the population at large and acute sleep deprivation may not be a perfect analog for short sleep. To address these limitations, population based studies have explored associations between proinflammatory markers and habitual sleep duration. This review summarizes what is known from experimental and cross-sectional studies about the association between sleep duration, cardiovascular disease, and proinflammatory biomarkers. First, the association between sleep duration with both morbidity and mortality, with a focus on cardiovascular disease, is reviewed. Then, a brief review of the potential role of proinflammatory markers in cardiovascular disease is presented. The majority of this review details specific findings related to specific molecules, including tumor necrosis factor-?, interleukins-1, -6, and -17, C-reactive protein, coagulation molecules, cellular adhesion molecules, and visfatin. Finally, a discussion of the limitations of current studies and future directions is provided. PMID:23901303

Grandner, Michael A; Sands-Lincoln, Megan R; Pak, Victoria M; Garland, Sheila N

2013-01-01

127

The NASA Balloon Program: conventional and long duration  

NASA Astrophysics Data System (ADS)

The U. S. National Aeronautics and Space Administration (NASA) Balloon Program has continued to maintain its highly successful performance record in support of scientific ballooning. The Program has broadened its support for the ballooning community through the enhancement of current capabilities and the development of new capabilities. The long duration balloon project has continued to mature; the Antarctic long duration capability has been declared operational, and the successful conclusion of the development effort will be realized in the very near future with the completion of mid-latitude long duration capability. Recent years have seen increases in the number and complexity of remote campaigns requirements. New ground station support equipment has been implemented, the new mobile launch vehicle has became operational, and new systems have been developed to meet the increasing demands. The comprehensive research and development (R&D) effort has continued with advances being made across the spectrum of balloon related disciplines. An overview of the various aspects of the NASA Balloon Program, their progress, status, and future plans will be presented.

Needleman, H. C.

128

Ongoing behavior predicts perceptual report of interval duration  

PubMed Central

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

Gouvea, Thiago S.; Monteiro, Tiago; Soares, Sofia; Atallah, Bassam V.; Paton, Joseph J.

2014-01-01

129

STS mission duration enhancement study: (orbiter habitability)  

NASA Technical Reports Server (NTRS)

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.

Carlson, A. D.

1979-01-01

130

Thermoresponsive nanogels for prolonged duration local anesthesia  

PubMed Central

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

Hoare, Todd; Young, Stuart; Lawlor, Michael W.; Kohane, Daniel S.

2012-01-01

131

Statistical analysis of random duration times  

SciTech Connect

This report presents basic statistical methods for analyzing data obtained by observing random time durations. It gives nonparametric estimates of the cumulative distribution function, reliability function and cumulative hazard function. These results can be applied with either complete or censored data. Several models which are commonly used with time data are discussed, and methods for model checking and goodness-of-fit tests are discussed. Maximum likelihood estimates and confidence limits are given for the various models considered. Some results for situations where repeated durations such as repairable systems are also discussed.

Engelhardt, M.E.

1996-04-01

132

Breastfeeding duration among low income women  

Microsoft Academic Search

Breastfeeding has been identified as a possible deterrent to the development of osteoporosis and breast cancer in women. In addition, infants who are breastfed exclusively for at least 4 months reportedly have fewer incidence of SIDS, ear infection, diarrhea, and allergies. Further, low income women who breastfeed may be empowered by the experience. Increasing the frequency and duration of breastfeeding

Renee A Milligan; Linda C Pugh; Yvonne L Bronner; Diane L Spatz; Linda P Brown

2000-01-01

133

Unemployment Duration of Spouses: Evidence From France  

E-print Network

is an important reason that leads to marriage, or any other form of partnership.1 In particular, marriage is seen, while it is decreasing in husband's earnings for women. To adjust for endogenous selection into marriage for men in the data. Keywords: unemployment duration, hazard models, labor income, marriage, joint search

Paris-Sud XI, Université de

134

The ATIC long duration balloon project  

Microsoft Academic Search

Long Duration Balloon (LDB) scientific experiments, launched to circumnavigate the south pole over Antarctica, have particular advantages compared to Shuttle or other Low Earth Orbit (LEO) missions in terms of cost, weight, scientific “duty factor” and work force development. The Advanced Thin Ionization Calorimeter (ATIC) cosmic-ray astrophysics experiment is a good example of a university-based project that takes full advantage

T. G. Guzik; J. H. Adams; H. S. Ahn; G. Bashindzhagyan; J. Chang; M. Christl; A. R. Fazely; O. Ganel; D. Granger; R. Gunasingha; Y. J. Han; J. B. Isbert; H. J. Kim; K. C. Kim; S. K. Kim; E. Kouznetsov; M. Panasyuk; A. Panov; B. Price; G. Samsonov; W. K. H. Schmidt; E. S. Seo; R. Sina; N. Sokolskaya; M. Stewart; A. Voronin; J. Z. Wang; J. P. Wefel; J. Wu; V. Zatsepin

2004-01-01

135

College depression: causes, duration, and coping.  

PubMed

Analysis of 149 responses (based on a 15% random college sample) indicated that 90% considered they were or had been depressed at college. Depression was usually moderate and of short duration and associated with boyfriend/girlfriend difficulties, other social adjustment, and grades. These students turned to friends, themselves, and parents for help. Treatment could be provided by a college. PMID:8559924

Oswalt, R; Finkelberg, S

1995-12-01

136

Predicting and Explaining Success and Task Duration  

E-print Network

that affect the success and the duration of fire-fighting episodes, it does not explain how these factors of Computer Science University of Massachusetts Amherst, MA 01003 Abstract Phoenix is a multi-agent planning system that fights simulated forest fires. In this paper we describe an experiment with Phoenix in which

137

Maternal recall of exclusive breast feeding duration  

PubMed Central

Background: Both the pattern and duration of breast feeding are important determinants of health outcomes. In vertical HIV transmission research, reliable documentation of early breast feeding practices is important in order to correctly attribute postnatal transmission to feeding pattern. Aims: To validate methods of collecting data on the duration of exclusive breast feeding (EBF) in an area of South Africa with a high HIV prevalence rate. Methods: A total of 130 mothers were interviewed weekly, postnatally. At every interview a 48 hour and a seven day recall breast feeding history were taken. A subset of 70 mothers also received two intermediate visits per week during which additional 48 hour, non-overlapping, recall interviews were conducted. Ninety three infants were revisited at 6–9 months of age when mothers' recall of EBF duration from birth was documented. The different methods of recalling EBF status were compared against an a priori "best comparison" in each case. Results: Reported breast feeding practices over the previous 48 hours did not reflect EBF practices since birth (specificity 65–89%; positive predictive value 31–48%). Six month EBF duration recall was equally poor (sensitivity at 2 weeks 79%; specificity 40%). Seven day recall accurately reflected EBF practices compared with thrice weekly recall over the same time period (sensitivity 96%, specificity 94%). Conclusions: 48 hour EBF status does not accurately reflect feeding practices since birth. Long term recall data on EBF are even more inaccurate. We recommend that data on duration of EBF be collected prospectively at intervals of no longer than one week. PMID:12937095

Bland, R; Rollins, N; Solarsh, G; Van den Broeck, J; Coovadia, H

2003-01-01

138

The duration of volcanism in Mare Serenitatis  

NASA Technical Reports Server (NTRS)

The crystallization ages of a suite of Apollo 17 basalts from four different stations have been measured using the Ar-39 to Ar-40 stepwise heating technique. The rocks analyzed include all principal petrographic types found at Apollo 17 landing site. A correlation between the ages and the petrographic type exists; plagioclase-poikilitic ilmenite basalts are youngest and olivine porphyritic ilmenite basalts are the oldest. The duration of volcanism in Mare Serenitatis is about 200 million years, the same as observed for Mare Imbrium, and less than observed for Mare Tranquillitatis, 400 million years. A relationship between duration of volcanism and gravity anomalies is noted. The cosmic ray exposure ages (in millions of years) for various locations range as: station 4, 58-315; station 5, 85-440; station 6, 110; station 8, 90-160.

Schaeffer, O. A.; Husain, L.; Schaeffer, G. A.

1976-01-01

139

Cryogenic systems for Long Duration Balloon experiments .  

NASA Astrophysics Data System (ADS)

We describe typical long duration cryostats, suitable for cooling large balloon-borne photometers for mm and sub-mm range. The idea, well tested in several experiments, is to thermally insulate the coldest part of the system from the room temperature shell by interposing layers with gradually decreasing temperature. In this way the heat load on the cold system is remarkably reduced. The target of a long hold time is achieved reducing the radiative loads by means of a super-insulation blanket for the nitrogen tank and a vapor-cooled shield for the helium tank. All the components are supported by fiberglass tubes. This class of cryostats operates autonomously without external power, for all the long duration balloon flight, that is typically longer than two weeks.

Nat, L.; Calv, M.; de Bernardi, P.; Fiadin, P.; Lamagn, L.; Mas, S.; Piacentin, F.; Rispol, R.

140

The employment service and vacancy durations.  

PubMed

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

Behrenz, Lars

2002-12-01

141

Silence Locations And Durations In Dialog Management  

Microsoft Academic Search

This discussion addresses the use of silence (pauses) in discourse as a mechanism to provide turn-taking cues to the user\\u000a of a voice-activated service. The location and duration of silence are defined and tested for a typical application, voice\\u000a controlled voice mail. Usability studies were performed in numerous European countries, as well as in the United States to\\u000a validate the

Matthew Yuschik

142

ON THE DURATION OF BLAZAR SYNCHROTRON FLARES  

SciTech Connect

A semi-analytical model is presented that describes the temporal development of a blazar synchrotron flare for the case of a broadband synchrotron power spectrum. We examine three different injection scenarios and present its influence on the synchrotron flare. An accurate approximation of the half-life of a synchrotron flare is analytically computed and we give some illustrative examples of the time evolution of the emergent synchrotron intensity by using a numerical integration method. The synchrotron flare starts at all photon energies right after the injection of ultrarelativistic electrons into the spherical emission volume of radius R and its duration exceeds the light travel time 2R/c in the low energy regime. Furthermore, the flare duration extends by the period of injection of relativistic electrons into the emission knot. However, the energetic and spatial distribution of these injected electrons has no significant influence on the flare duration. We obtain a temporal behavior that agrees most favorably with the observations of PKS 2155-304 on 2006 July 29-30 and it differs considerably from the results that were recently achieved by using a monochromatic approximation of the synchrotron power.

Eichmann, B.; Schlickeiser, R. [Institut fuer Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universitaet Bochum, 44780 Bochum (Germany); Rhode, W. [Experimentelle Physik V, Technische Universitaet Dortmund, 44221 Dortmund (Germany)

2012-01-10

143

Effects of the shock duration on the response of CFRP composite laminates  

NASA Astrophysics Data System (ADS)

Shock loads induce a local tensile stress within a sample. The location and amplitude of this high strain rate stress can be monitored respectively by the duration and intensity of the shock. The process is applied to carbon fibre reinforced polymer (CFRP) composites, involved in aeronautic or defense industry. This paper describes the response of CFRP laminates of different thicknesses to a shock load normal to the fibres direction. The effects of the shock duration on the wave propagation are key issues of this work. Experiments have been performed on high power laser facilities and on a high power pulsed generator to get a wide range of pulse duration from fs to µs. Numerical simulation provides a comprehensive approach of the wave propagation and tensile stress generation within these complex materials. The main result concerns the relation between the load duration, the tensile stress and the induced delamination within 1, 4 and 8 ply composite laminates.

Gay, Elise; Berthe, Laurent; Boustie, Michel; Arrigoni, Michel; Buzaud, Eric

2014-11-01

144

Discrete shocks and fixed duration of labor contracts  

Microsoft Academic Search

This paper examines the choice between fixed and stochastic durations of labor contracts in an economy with discrete shocks. The stochastic duration expires when the consumer price index reaches a lower or upper limit. The paper proves that any contract with a stochastic duration is dominated by a contract with a fixed duration, except for the contract that expires at

Leif Danziger

1995-01-01

145

RANKING MUTUALLY EXCLUSIVE PROJECTS: THE ROLE OF DURATION  

Microsoft Academic Search

This paper develops a new measure of cash-flow timing called “return duration.” Numerically quite close to Macaulay duration, return duration is a straightforward function of a project's net present value (NPV) and internal rate of return (IRR). When comparing mutually exclusive projects, differences in return duration can explain ranking conflicts between NPV and IRR. The paper also clarifies the conditions

L. Dwayne Barney; Morris G. Danielson

2004-01-01

146

Sequential forecast of incident duration using Artificial Neural Network models  

Microsoft Academic Search

This study creates an adaptive procedure for sequential forecasting of incident duration. This adaptive procedure includes two adaptive Artificial Neural Network-based models as well as the data fusion techniques to forecast incident duration. Model A is used to forecast the duration time at the time of incident notification, while Model B provides multi-period updates of duration time after the incident

Chien-Hung Wei; Ying Lee

2007-01-01

147

16 CFR 613.1 - Duration of active duty alerts.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Duration of active duty alerts. 613.1 Section 613.1 Commercial...CREDIT REPORTING ACT DURATION OF ACTIVE DUTY ALERTS § 613.1 Duration of active duty alerts. The duration of an active duty alert...

2011-01-01

148

16 CFR 613.1 - Duration of active duty alerts.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Duration of active duty alerts. 613.1 Section 613.1 Commercial...CREDIT REPORTING ACT DURATION OF ACTIVE DUTY ALERTS § 613.1 Duration of active duty alerts. The duration of an active duty alert...

2010-01-01

149

16 CFR 613.1 - Duration of active duty alerts.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Duration of active duty alerts. 613.1 Section 613.1 Commercial...CREDIT REPORTING ACT DURATION OF ACTIVE DUTY ALERTS § 613.1 Duration of active duty alerts. The duration of an active duty alert...

2012-01-01

150

Objective Quantification of Drought Severity and Duration.  

NASA Astrophysics Data System (ADS)

Common weaknesses of current drought indexes were analyzed. First, most of the current indexes are not precise enough in detecting the onset, end, and accumulated stress of drought. Second, they do not effectively take into account the aggravating effects of runoff and evapotranspiration, which build up with time. Third, they have a limited usefulness in monitoring ongoing drought because they are based on a monthly time step. Fourth, most of them fail to differentiate the effects of drought on surface and subsurface water supply.A new series of indexes are proposed to solve these weaknesses and to improve drought monitoring. In the new indexes, daily, rather than monthly, time steps are used. A new concept, effective precipitation (EP), the summed value of daily precipitation with a time-dependent reduction function, is proposed as a basic tool.Three additional indexes complement EP. The first index is each day's mean of EP (MEP). This index shows climatological characteristics of precipitation as a water resource for a station or area. The second index is the deviation of EP (DEP) from the MEP. The third index is the standardized value of DEP (SEP). By using these three indexes, consecutive days of negative SEP, which can show the onset, the ending date, and the duration of a water deficit period is categorized.With the duration categorized, four additional indexes that can show drought severity are calculated: 1) accumulation of consecutive negative SEP, which shows the duration and severity of precipitation deficit together;2) accumulated precipitation deficit, which shows precipitation departure from the normal during a defined period; 3) precipitation for the return to normal; and 4) effective drought index, a standardized index that can be used to assess drought severity worldwide. The merits and weaknesses of each index are compared. New quantified definitions on drought and its onset, end, and duration are proposed.These indexes were tested in the High Plains region of the United States from 1960 to 1996. The results were compared to historical reports of drought. From this analysis, it was concluded that the new indexes not only advanced objectivity, but also offered a number of advantages in practical use. These are 1) a more precise determination of drought duration, 2) the usefulness in monitoring an ongoing drought, and 3) the variety of ways a drought's characteristics can be described.

Byun, Hi-Ryong; Wilhite, Donald A.

1999-09-01

151

The long duration exposure facility structural interface  

NASA Technical Reports Server (NTRS)

The development of an efficient structural interface between the Long Duration Exposure Facility (LDEF) and the space shuttle orbiter is discussed. Thermal gradients and manufacturing tolerances restrict the number of retention points in the shuttle to four with no more than three in one plane. Loads during the powered exit, high drag reentry, and landing are also critical factors in the location of retention points. A LDEF design is described that meets all requirements while avoiding the structural weight penalties associated with an asymmetrical arrangement. The ground handling and assembly problems are resolved in an economical and effective manner.

Long, M. J.

1981-01-01

152

Long Duration Exposure Facility (LDEF) Archive System  

SciTech Connect

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.

Wilson, B.K.

1995-02-01

153

Training Concept for Long Duration Space Mission  

NASA Technical Reports Server (NTRS)

There has been papers about maintenance and psychological training for Long Duration Space Mission (LDSM). There are papers on the technology needed for LDSMs. Few are looking at how groundbased pre-mission training and on-board in-transit training must be melded into one training concept that leverages this technology. Even more importantly, fewer are looking at how we can certify crews pre-mission. This certification must ensure, before the crew launches, that they can handle any problem using on-board assets without a large ground support team.

O'Keefe, William

2008-01-01

154

Performance Analysis of a Finite Duration Multichannel Delivery Method in IPTV  

Microsoft Academic Search

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

Weiqiang Sun; Kan Lin; Yang Guan

2008-01-01

155

Sleep duration and incidence of lung cancer in ageing men  

PubMed Central

Background Previous studies have suggested an association between sleep duration and cancer. However, the information on sleep duration regard to risk of lung cancer is scanty. Methods Analysed data comprised prospective population-based cohort of 2586 men (aged 42–60 years) from Eastern Finland. Baseline survey and clinical examinations took place 1984–1989, and diagnosed lung cancers were obtained until the end of 2011 through linkage with the Finnish Cancer Registry. Self-reported sleep was categorized as ?6.5 h, 7–7.5 h, and ?8 h. Subjects with prior history of cancer or psychotropic medication (hypnotics or sedatives) were excluded from the analyses. Cox proportional hazards models with adjustments for possible confounders were used to examine the association. Results Significant association between sleep duration and increased lung cancer risk was observed after adjustments for age, examination years, cumulative smoking history, family cancer history and Human Population Laboratory Depression scale scores (HR 2.12, 95% CI 1.17-3.85 for ?6.5 h sleep, and HR 1.88, 95% CI 1.09-3.22 for ?8 h sleep). Associations were even stronger among current smokers (HR 2.23, 95% CI 1.14-4.34 for ?6.5 h sleep, and HR 2.09, 95% CI 1.14-3.81 for ?8 h sleep). After further adjustments for alcohol consumption, physical activity, body mass index, marital status, education years, night work, employment status, asthma and chronic bronchitis, the association remained significant both in the whole study population and among smokers. When cumulative smoking history was replaced by current smoking in the adjustments, the increased risk was limited to those who slept <6.5 h. Conclusions Sleep duration of less than 7–7.5 hours or more than 7–7.5 hours associates with increased lung cancer risk. The physiological factors underlying the association are complex, and they may relate to melatonin excretion patterns, low-grade inflammation in cancer development process or disruptions in circadian rhythmicity. PMID:24684747

2014-01-01

156

CONCORDIASI, Long Duration Stratospheric Balloons over Antarctica  

NASA Astrophysics Data System (ADS)

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.

Cocquerez, Philippe

2012-07-01

157

Estimating potential diapause duration in Calanus finmarchicus  

NASA Astrophysics Data System (ADS)

Deep basins in the Gulf of Maine act as refuge for a large population of diapausing Calanus finmarchicus during the summer and fall. This population acts as the primary seed population for Georges Bank in the spring and is thought to be composed primarily of individuals that developed during the previous spring bloom. The factors affecting growth and mortality in the summer-fall population are not well understood, however, and loss terms from advection and starvation may be large. To assess the potential energetic limitation and loss of C. finmarchicus from the Gulf of Maine basins, a new nitrogen-specific respiration model has been developed for the resting stage of the species. Stage C5 C. finmarchicus were collected during July, September, and December 2003 from Wilkinson and Georges Basins. Animals were collected using both MOCNESS tows and zooplankton samplers on the Johnson Sea Link II submersible. Metabolic rates were measured using a Micro-Oxymax gas analyzer and Winkler incubation techniques both at sea and on animals kept in culture on shore. Respiration rates measured in the field were not significantly different from those measured on shore, with a mean of 130 ?mol O 2 gN -1 h -1 (14.4 ?mol O 2 gC -1 h -1) at 0 °C and a Q10 of 2.77 (2.58 for carbon-specific respiration). Using the nitrogen-specific rates in conjunction with visual estimates of nitrogen weight and lipid stores, we derived a discrete function for predicting potential diapause duration based on an animal's length, oil sac volume, and the in situ temperature. The maximum potential diapause duration for a C5 C. finmarchicus is predicted to range from 280 days at 0 °C to approximately 90 days at 11 °C. The maximum potential diapause duration in the Gulf of Maine is predicted to be between 3.5 and 5.5 months. These results suggest that energetic limitation may play a role in controlling the population dynamics of diapausing C. finmarchicus in the Gulf of Maine. A reassessment of the importance of summer production to the Gulf of Maine C. finmarchicus population may be required to account for its year-round presence on the Northeast American Shelf.

Saumweber, Whitley J.; Durbin, Edward G.

2006-11-01

158

Short Duration Base Heating Test Improvements  

NASA Technical Reports Server (NTRS)

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.

Bender, Robert L.; Dagostino, Mark G.; Engel, Bradley A.; Engel, Carl D.

1999-01-01

159

Feeding the Astronauts During Long Duration Missions  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the issues surrounding feeding astronauts during long duration missions. There is a brief history from the food and food packaging available during Project Mercury through the current food requirements. It shows the packaging and the requirements that have been used. The current food system includes thermostabilized and irradiated foods to reduce the potential of harmful microorganisms. There is an explanation of drinks available, rehydratable foods, and natural forms of food, (i.e., commercially available foods that are packaged in individual serving sizes). There is also discussion of the requirements for future missions, and the research gap for requirements for food that will last 5 years, with packaging and nutrients intact.

Perchonok, Michele

2010-01-01

160

Long Duration Backlighter Experiments at Omega  

SciTech Connect

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.

Reighard, A; Glendinning, S; Young, P; Hsing, W; Foord, M; Schneider, M; Lu, K; Dittrich, T; Wallace, R; Sorce, C

2008-05-01

161

Long duration backlighter experiments at Omega  

SciTech Connect

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 {mu}m diameter pinhole in a 75 {mu}m thick Ta substrate separated from a Zn emitter (9 keV) by a 400 {mu}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.

Reighard, A. B.; Glendinning, S. G.; Young, P. E.; Hsing, W. W.; Foord, M.; Schneider, M.; Lu, K.; Dittrich, T.; Wallace, R.; Sorce, C. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

2008-10-15

162

Expanded capabilities of the Extended Duration Orbiter  

NASA Technical Reports Server (NTRS)

The Extended Duration Orbiter (EDO) is presented emphasizing the ability of the program to enhance the stay times of Spacelab, Spacehab, and Commercially Developed Space Facility missions. An overview of EDO is given with particular attention given to the modifications required for the implementation of Environmental Control and Life Support Systems specific to the Space Shuttle. The configuration, operation, and location of proposed regenerative CO2 removal, N2 supply, improved waste-collection, and power-reactant storage and distribution systems are described in detail. The EDO also includes a trash compactor, additional cryogenic hydrogen and oxygen, extra gaseous nitrogen, and a method for reducing stowed lithium hydroxide. The first utilization of the EDO system is a 13-day mission on the space shuttle Columbia planned for March 1992.

Cerna, Peter J.; Williams, David E.

1990-01-01

163

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...

2010-07-01

164

33 CFR 64.23 - Duration of marking on structures.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 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...

2012-07-01

165

33 CFR 64.23 - Duration of marking on structures.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 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...

2013-07-01

166

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...

2011-07-01

167

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...CERTIFICATION Certificates Under International Convention for Safety of Life at Sea...189.60-40 Duration of Convention certificates. (a)...

2010-10-01

168

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...CERTIFICATION Certificates Under International Convention for Safety of Life at Sea...91.60-40 Duration of Convention certificates. (a)...

2010-10-01

169

20 CFR 655.158 - Duration of positive recruitment.  

Code of Federal Regulations, 2010 CFR

20 Employees' Benefits 3 ...Duration of positive recruitment. 655.158 Section 655.158 Employees' Benefits EMPLOYMENT...Certification Process for Temporary Agricultural...Duration of positive recruitment. Except as...

2010-04-01

170

20 CFR 655.158 - Duration of positive recruitment.  

20 Employees' Benefits 3 ...Duration of positive recruitment. 655.158 Section 655.158 Employees' Benefits EMPLOYMENT...Certification Process for Temporary Agricultural...Duration of positive recruitment. Except as...

2014-04-01

171

20 CFR 655.158 - Duration of positive recruitment.  

Code of Federal Regulations, 2012 CFR

20 Employees' Benefits 3 ...Duration of positive recruitment. 655.158 Section 655.158 Employees' Benefits EMPLOYMENT...Certification Process for Temporary Agricultural...Duration of positive recruitment. Except as...

2012-04-01

172

20 CFR 655.158 - Duration of positive recruitment.  

Code of Federal Regulations, 2013 CFR

20 Employees' Benefits 3 ...Duration of positive recruitment. 655.158 Section 655.158 Employees' Benefits EMPLOYMENT...Certification Process for Temporary Agricultural...Duration of positive recruitment. Except as...

2013-04-01

173

20 CFR 655.158 - Duration of positive recruitment.  

Code of Federal Regulations, 2011 CFR

20 Employees' Benefits 3 ...Duration of positive recruitment. 655.158 Section 655.158 Employees' Benefits EMPLOYMENT...Certification Process for Temporary Agricultural...Duration of positive recruitment. Except as...

2011-04-01

174

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...

2010-04-01

175

10 CFR 451.6 - Duration of incentive payments.  

Code of Federal Regulations, 2011 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...

2011-01-01

176

10 CFR 451.6 - Duration of incentive payments.  

Code of Federal Regulations, 2012 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...

2012-01-01

177

10 CFR 451.6 - Duration of incentive payments.  

...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...

2014-01-01

178

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...

2013-01-01

179

Architectural considerations for lunar long duration habitat  

NASA Astrophysics Data System (ADS)

The future of space exploration science and technology is expected to move toward long duration missions. During this long duration missions the most important factor to success will be the habitation system, the place that crew will live and work. The broad range of future space exploration, new advances in technology and increasing demand for space travel and space tourism will create great opportunities for architects to use their special abilities and skills in the realm of space. The lunar habitat is defined as a multidisciplinary task and cannot be considered an independent project from the main module. Therefore, habitability will become the most important aspect of future human exploration. A successful design strategy should integrate architecture, structure and other disciplines and should bring in elements such as psychological and physiological factors, human interfaces, and privacy. The current research provides "Habitat Architectural Design System (HADS)" in order to evaluate lunar habitat concepts based on habitability, functional optimization, and human factors. HADS helps to promote parametric studied and evaluation of habitat concepts. It will provide a guideline dependent upon mission objectives to standardize architectural needs within the engineering applications and scientific demands. The significance of this research is the process of developing lunar habitat concepts using an architectural system to evaluate the quality of each concept via habitability aspects. This process can be employed during the early stage of design development and is flexible enough to be adjusted by different parameters according to the objectives of lunar mission, limitations, and cost. It also emphasizes the importance of architecture involvement in space projects, especially habitats.

Bahrami, Payam

180

Prediction of Daily Flow Duration Curves and Streamflow for Ungauged Catchments Using Regional Flow Duration Curves  

EPA Science Inventory

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...

181

Space Complexity Algorithms & Complexity  

E-print Network

Space Complexity Algorithms & Complexity Space Complexity Nicolas Stroppa Patrik Lambert - plambert@computing.dcu.ie CA313@Dublin City University. 2008-2009. December 4, 2008 #12;Space Complexity Hierarchy of problems #12;Space Complexity NP-intermediate Languages If P = NP, then are there languages which neither in P

Way, Andy

182

Management and Conservation Stopover Duration of Fall-Migrating  

E-print Network

(stopover duration) and the rate of refueling define the overall migration strategy and determineManagement and Conservation Stopover Duration of Fall-Migrating Dabbling Ducks BENJAMIN J. O'NEAL,1 migrating birds spend at stopover sites, or stopover duration, partially determines an individual's access

183

Decoding stimulus duration from neural responses in the auditory midbrain.  

PubMed

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

Aubie, Brandon; Sayegh, Riziq; Fremouw, Thane; Covey, Ellen; Faure, Paul A

2014-11-15

184

What is the best segment duration for music mood analysis ?  

Microsoft Academic Search

Music mood present the inherent emotional state of music on certain duration of music segment. However, the mood may vary in the music pieces. Thus it is important to investigate the duration of music segments which can best present the stable mood states in music. Four versions of music datasets with duration of clips from 4 seconds to 32 seconds

Zhongzhe Xiao; Emmanuel Dellandrea; Weibei Dou; Liming Chen

2008-01-01

185

Notes on Duration as an Attribute of Sensations  

Microsoft Academic Search

The relation of any mental process to duration may be conceived in four different ways. In the first place, such a process may occupy a certain period of what we may call objective time, quite apart from any corresponding consciousness of its duration. Secondly, a mental process may possess duration for the consciousness in which it occurs. Thirdly, it may

Margaret Floy Washburn

1903-01-01

186

Dietary nutrients associated with short and long sleep duration. Data from a nationally representative sample?  

PubMed Central

Short sleep duration is associated with weight gain and obesity, diabetes, cardiovascular disease, psychiatric illness, and performance deficits. Likewise, long sleep duration is also associated with poor physical and mental health. The role of a healthy diet in habitual sleep duration represents a largely unexplored pathway linking sleep and health. This study evaluated associations between habitual sleep parameters and dietary/nutritional variables obtained via the National Health and Nutrition Examination Survey (NHANES), 2007–2008. We hypothesized that habitual very short (<5 h) short (5–6 h) and long (9+ h) sleep durations are associated with intake of a number of dietary nutrient variables. Overall, energy intake varied across very short (2036 kcal), short (2201 kcal), and long (1926 kcal) sleep duration, relative to normal (2151 kcal) sleep duration (p = 0.001). Normal sleep duration was associated with the greatest food variety (17.8), compared to very short (14.0), short (16.5) and long (16.3) sleep duration (p < 0.001). Associations between sleep duration were found across nutrient categories, with significant associations between habitual sleep duration and proteins, carbohydrates, vitamins and minerals. In stepwise analyses, significant contributors of unique variance included theobromine (long sleep RR = 0.910, p < 0.05), vitamin C (short sleep RR = 0.890, p < 0.05), tap water (short sleep RR = 0.952, p < 0.001; very short (<5 h) sleep RR = 0.941, p < 0.05), lutein + zeaxanthin (short sleep RR = 1.123, p < 0.05), dodecanoic acid (long sleep RR = 0.812, p < 0.05), choline (long sleep RR = 0.450, p = 0.001), lycopene (very short (<5 h) sleep RR = 0.950, p <0.05), total carbohydrate (very short (<5 h) sleep RR = 0.494, p <0.05; long sleep RR = 0.509, p <0.05), selenium (short sleep RR = 0.670, p <0.01) and alcohol (long sleep RR = 1.172, p < 0.01). Overall, many nutrient variables were associated with short and/or long sleep duration, which may be explained by differences in food variety. Future studies should assess whether these associations are due to appetite dysregulation, due to short/long sleep and/or whether these nutrients have physiologic effects on sleep regulation. In addition, these data may help us better understand the complex relationship between diet and sleep and the potential role of diet in the relationship between sleep and obesity and other cardiometabolic risks. PMID:23339991

Grandner, Michael A.; Jackson, Nicholas; Gerstner, Jason R.; Knutson, Kristen L.

2013-01-01

187

Endocardial focal activation originating from Purkinje fibers plays a role in the maintenance of long duration ventricular fibrillation  

PubMed Central

Aim To determine the role of repetitive endocardial focal activations and Purkinje fibers in the maintenance of long duration ventricular fibrillation (LDVF, VF>1 minute) in canine hearts in vivo. Methods The study was conducted in electrophysiological laboratory of Shanghai Ruijin hospital from July 2010 to August 2012. A 64-electrode basket was introduced through a carotid artery into the left ventricle (LV) of 11 beagle dogs for global endocardial electrical mapping. In the Lugol’s solution group (n?=?5), the subendocardium was ablated by washing with Lugol’s solution. In the control group, (n?=?6) saline was used for ablation. Before and after saline or Lugol ablation, we determined QRS duration and QT/QTc interval in sinus rhythm (SR). We also measured the activation rates in the first 2 seconds of each minute during 7 minutes of VF for each group. If VF terminated spontaneously in less than 7 minutes, the VF segments used in activation rate analysis were reduced accordingly. Results At the beginning of VF there was no difference between the groups in the activation rate. However, after 1 minute of LDVF the Lugol’s solution group had significantly slower activation rate than the control group. In the control group, all episodes of LDVF (6/6) were successfully sustained for 7 minutes, while in the Lugol’s solution group 4/5 episodes of LDVF spontaneously terminated before 7 minutes (4.8?±?1.4 minutes) (P?=?0.015). In the control group, at 5.1?±?1.3 minutes of LDVF, a successive, highly organized focal LV endocardial activation pattern was observed. During this period, activations partly arose in PF and spread to the working ventricular myocardium. Mapping analysis showed that these events were consistent with repetitive endocardial focal activations. No evidence of similar focal activations was observed in the Lugol’s solution group. Conclusions Repetitive endocardial focal activations in the LV endocardium may be associated with activation of subendocardial PFs. This mechanism may play an important role in the maintenance of LDVF. PMID:24778098

Lin, Changjian; Jin, Qi; Zhang, Ning; Zhou, Jian; Pang, Yang; Xin, Yangxun; Liu, Shaohua; Wu, Qiong; Wu, Liqun

2014-01-01

188

A sensing duration optimization algorithm in cognitive radio  

NASA Astrophysics Data System (ADS)

In a periodic spectrum sensing framework where each frame consists of a sensing duration and a data transmitting duration, the sensing duration to use is a trade-off between sensing performance and system efficiencies. The relationships between sensing duration and state transition probability are analyzed firstly, when the licensed channel stays in the idle and busy states respectively. Then a state transition probability based sensing duration optimization algorithm is proposed, which can dynamically optimize the sensing duration of each frame. Analysis and simulation results reveal that the proposed algorithm can use as little sensing duration in each frame as possible to satisfy the sensing performance constraints so as to maximize the energy and transmitting efficiencies of the cognitive networks.

Liu, Yuexuan; Liang, Shujian; Zhang, Xiao

2013-03-01

189

Analysis of the duration of migraine prophylaxis.  

PubMed

To determine the minimum duration of migraine prophylaxis, after patients become pain-free. Migraine patients diagnosed according to criteria of International Classification of Headache Disorders-2 were treated prophylactically. After becoming pain-free, they were divided into two equal groups: in group 1, prophylaxis was maintained for another 12 months and in group 2, for 24 months. Each group was followed for more three years after prophylaxis period. Of the 50 patients, 39 (78%) were female and 11 (22%) were male. The age ranged from 18 to 50 years. Before treatment, the attack frequency for groups 1 and 2 was, respectively, 16.3 ± 12.8 and 16.4 ± 11.8 days per month (p = 0.769). Patients in groups 1 and 2 have become pain-free, respectively, with 21.4 ± 11.2 and 16.8 ± 9.9 months (p = 0.161). During three years without treatment, groups 1 and 2 maintained an annual frequency of respectively 3.2 and 0.5 headache days. Of the patients in group 2, 76.0% (19/25) remained pain-free during follow-up, versus 44.0% (11/25) of group 1, with a significant difference (p=0.001). The best results were obtained when migraine prophylaxis was maintained for 24 months after patients became pain-free. PMID:24308946

Silva-Néto, Raimundo Pereira; Almeida, Kelson James; Bernardino, Silvya Neri

2014-02-15

190

Immune changes during short-duration missions  

NASA Technical Reports Server (NTRS)

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.

Taylor, G. R.

1993-01-01

191

Long Duration Space Materials Exposure (LDSE)  

NASA Technical Reports Server (NTRS)

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.

Allen, David; Schmidt, Robert

1992-01-01

192

The ATIC Long Duration Balloon Project  

NASA Technical Reports Server (NTRS)

Long Duration Balloon (LDB) scientific experiments, launched to circumnavigate the south pole over Antarctica, have particular advantages compared to Shuttle or other Low Earth Orbit (LEO) missions in terms of cost, weight, scientific 'duty factor' and work force development. The Advanced Thin Ionization Calorimeter (ATIC) cosmic ray astrophysics experiment is a good example of a university-based project that takes full advantage of current LDB capability. The ATIC experiment is currently being prepared for its first LDB science flight that will investigate the charge composition and energy spectra of primary cosmic rays over the energy range from about 10(exp 10) to 10(exp 14) eV. The instrument is built around a fully active, Bismuth Germanate (BGO) ionization calorimeter to measure the energy deposited by the cascades formed by particles interacting in a thick carbon target. A highly segmented silicon matrix, located above the target, provides good incident charge resolution plus rejection of the 'backscattered' particles from the interaction. Trajectory reconstruction is based on the cascade profile in the BGO calorimeter, plus information from the three pairs of scintillator hodoscope layers in the target section above it. A full evaluation of the experiment was performed during a test flight occurring between 28 December 2000 and 13 January 2001 where ATIC was carried to an altitude of approx. 37 km above Antarctica by an approx. 850,000 cu m helium filled balloon for one circumnavigation of the continent. All systems behaved well, the detectors performed as expected, more than 43 gigabytes of engineering and cosmic ray event data was returned and these data are now undergoing preliminary data analysis. During the coming 2002-2003 Antarctica summer season, we are preparing for a ATIC science flight with approx. 15 to 30 days of continuous data collection in the near-space environment of LDB float altitudes.

Guzik, T. G.; Adams, J. H.; Ahn, H. S.; Bashindzhagyan, G.; Chang, J.; Christl, M.; Fazely, A. R.; Ganel, O.; Granger, D.; Gunasingha, R.

2003-01-01

193

Personal growth following long-duration spaceflight  

NASA Astrophysics Data System (ADS)

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.

Suedfeld, Peter; Brcic, Jelena; Johnson, Phyllis J.; Gushin, Vadim

2012-10-01

194

49 CFR 525.9 - Duration of exemption.  

Code of Federal Regulations, 2010 CFR

...Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EXEMPTIONS FROM AVERAGE FUEL ECONOMY STANDARDS § 525.9 Duration of exemption. An exemption...

2010-10-01

195

Hazard based models for freeway traffic incident duration.  

PubMed

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

Tavassoli Hojati, Ahmad; Ferreira, Luis; Washington, Simon; Charles, Phil

2013-03-01

196

Sleep Duration and Depressive Symptoms: A Gene-Environment Interaction  

PubMed Central

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 × 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

Watson, Nathaniel F.; Harden, Kathryn Paige; Buchwald, Dedra; Vitiello, Michael V.; Pack, Allan I.; Strachan, Eric; Goldberg, Jack

2014-01-01

197

A STUDY ON THE DURATION OF STRONG EARTHQUAKE GROUND MOTION  

Microsoft Academic Search

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,

MI D. TRIFUNAC; A. G. BRADY

1975-01-01

198

Initiation of primary explosives by electron pulses of microsecond duration  

Microsoft Academic Search

The explosive decomposition of initiating explosives, namely, lead, silver, cadmium, and thallium azides, potassium picrate, lead styphnate, mercury fulminate, and tetrazene, on irradiation by electron pulses of various durations was studied. The critical parameters of electron pulses that initiate specimen explosions are determined. The critical energy density in pulses of microsecond duration is shown to be less than that in

S. M. Ryabykh; V. P. Zhulanova; N. V. Kholodkovskaya; V. G. Shakhovalov

1996-01-01

199

Stimulus Duration Preference at Electrode Sites Yielding Elicited Behavior  

NASA Technical Reports Server (NTRS)

The latency to display eating or drinking during hypothalamic stimulation was compared with the preferred duration of the same stimulus intensity in a self-stimulation situation. All the animals preferred longer stimulus durations than those required to elicit eating or drinking

Cox, V. C.

1970-01-01

200

The Duration Criteria of Delusional Disorder in Modern Classification  

Microsoft Academic Search

This article briefly reviews the duration criteria for delusional disorder in current diagnostic systems. Furthermore, a sample of 72 first-admitted patients with delusional disorder, personally re-examined after a mean of 10 and 27 years, has been analysed as to duration of delusional symptoms. One third of the sample displayed delusions for less than 6 months at admission. During the observation

Stein Opjordsmoen

1993-01-01

201

Duration of Sleep and ADHD Tendency among Adolescents in China  

ERIC Educational Resources Information Center

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 of…

Lam, Lawrence T.; Yang, L.

2008-01-01

202

Product Differentiation and Duration of US Import Trade Tibor Besedes  

E-print Network

Product Differentiation and Duration of US Import Trade Tibor Besedes Louisiana State University differentiation affects duration of US import trade relationships. The results are consistent with a matching model of trade formation. Using highly disaggregated product level data we estimate the hazard rate

Das, Suman

203

34 CFR 686.3 - Duration of student eligibility.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Duration of student eligibility. 686.3 Section...TEACHER EDUCATION ASSISTANCE FOR COLLEGE AND HIGHER EDUCATION (TEACH...Definitions § 686.3 Duration of student eligibility. (a) An undergraduate or post-baccalaureate student enrolled in a TEACH...

2013-07-01

204

34 CFR 686.3 - Duration of student eligibility.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Duration of student eligibility. 686.3 Section...TEACHER EDUCATION ASSISTANCE FOR COLLEGE AND HIGHER EDUCATION (TEACH...Definitions § 686.3 Duration of student eligibility. (a) An undergraduate or post-baccalaureate student enrolled in a TEACH...

2012-07-01

205

34 CFR 686.3 - Duration of student eligibility.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Duration of student eligibility. 686.3 Section...TEACHER EDUCATION ASSISTANCE FOR COLLEGE AND HIGHER EDUCATION (TEACH...Definitions § 686.3 Duration of student eligibility. (a) An undergraduate or post-baccalaureate student enrolled in a TEACH...

2011-07-01

206

Role of instantaneous force magnitude and duration on particle entrainment  

Microsoft Academic Search

A new criterion for the onset of entrainment of coarse sediment grains is presented here. It is hypothesized that not only the magnitude, but also the duration of energetic near bed turbulent events is relevant in predicting grain removal from the bed surface. It is therefore proposed that the product of force and its duration, or impulse, is a more

Manousos Valyrakis; Panayiotis Diplas; Clint L. Dancey; Krista Greer; Ahmet O. Celik

2010-01-01

207

The representativeness of observational samples of different durations.  

PubMed

The representativeness of behavioral observation samples with durations of less than the whole time of interest was investigated. A real-time recording system was developed to quantify the behavior of 5 profoundly mentally retarded physically handicapped adult students in an institutional training setting. Behavior was observed using six mutually exclusive and exhaustive categories during 2.5-hr observation sessions. Sample observation sessions with durations ranging from 15 to 135 min were computer simulated from the whole-session (150-min) records. It was found that the representativeness of these samples, when compared to whole-session records, was a function of the relative duration of the behavioral categories and of sample duration. The occurrence of relatively high-duration behaviors (lasting for more than 50% of the session) was estimated to within 20% error by samples of less than 60 min, but low-duration behaviors (1 to 3% of the session) were inadequately quantified even from 135-min samples. Increasing irregularity of bouts of behavior in the low-duration behaviors is suggested as the cause of the functions obtained. Implications of the findings for applied behavior analysis are discussed, with the recommendation that the adequacy of observational session durations be empirically assessed routinely. PMID:2249968

Mudford, O C; Beale, I L; Singh, N N

1990-01-01

208

Traffic Incident Duration Prediction Based on Artificial Neural Network  

Microsoft Academic Search

The prediction of traffic incident duration is an important foundation of advanced incident management system and driver information system. In this paper, actual traffic incident data was used to study the prediction problem of traffic incident duration by the method of neural network. 660 sets of actual traffic incident data from a freeway management center were used to train a

Liping Guan; Weiming Liu; Xiangyuan Yin; Luping Zhang

2010-01-01

209

Contrast, component duration, and the following schedule of reinforcement  

Microsoft Academic Search

Exp I (4 White Carneaux pigeons) investigated component duration in a 4-component multiple schedule designed to separate the effects of the preceding schedule of reinforcement from those of the following schedule (FS) of reinforcement. The preceding schedule in the preceding component had no consistent effect regardless of component duration. The FS was a powerful determinant of behavior with higher response

Ben A. Williams

1979-01-01

210

The Optimal Duration of Executive Compensation: Theory and Evidence  

E-print Network

compensation. This paper develops a new measure of CEO pay duration that reflects the vesting periods with poorer corporate governance. Third, CEOs with shorter pay durations are more likely to engage in myopic and Murphy (1990) famously argued that what matters in CEO pay is not how much you pay, but how you pay

211

Correcting Memory Improves Accuracy of Predicted Task Duration  

Microsoft Academic Search

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

Michael M. Roy; Scott T. Mitten; Nicholas J. S. Christenfeld

2008-01-01

212

Fighting in fiddler crabs Uca mjoebergi: what determines duration?  

Microsoft Academic Search

Contest duration in animals is often interpreted as being a consequence of mutual assessment of the difference in the competitors' resource-holding potential (RHP), allowing the inferior individual to avoid costly interactions it is likely to lose. Duration is thus predicted by the relative size of the competitors, and increases as the difference between them decreases. Alternatively, each individual may persist

Lesley J. Morrell; Patricia R. Y. Backwell; Neil B. Metcalfe

2005-01-01

213

Unemployment Insurance and Male Unemployment Duration in Canada  

Microsoft Academic Search

A model of unemployment duration is estimated with weekly micro data on Canadian men. Ent itlement provisions in the unemployment insurance program and demand conditions are found to have a significant effect on the probability of leaving unemployment. The probability of a worker leaving unemploy ment declines with the duration of unemployment, holding unemployment insurance entitlement constant. When entitlement is

John C. Ham

1987-01-01

214

34 CFR 686.3 - Duration of student eligibility.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Duration of student eligibility. 686.3 Section...TEACHER EDUCATION ASSISTANCE FOR COLLEGE AND HIGHER EDUCATION (TEACH...Definitions § 686.3 Duration of student eligibility. (a) An undergraduate or post-baccalaureate student enrolled in a TEACH...

2010-07-01

215

Fuzzy algorithm for estimation of solar irradiation from sunshine duration  

Microsoft Academic Search

Solar irradiation and sunshine duration are intimately related phenomena and a model involving the relationship between them can best be derived by methods that explicitly take vagueness into account. In this paper, the theory of fuzzy sets, especially fuzzy modeling, is employed to represent solar irradiation and sunshine duration relations as a set of fuzzy rules. A fuzzy logic algorithm

Zekai ?en

1998-01-01

216

Depth-duration frequency of precipitation for Texas  

USGS Publications Warehouse

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.

Asquith, William H.

1998-01-01

217

The Impact of Coping Style on Gaze Duration  

PubMed Central

The understanding of individual differences in response to threat (e.g., attentional bias) is important to better understand the development of anxiety disorders. Previous studies revealed only a small attentional bias in high-anxious (HA) subjects. One explanation for this finding may be the assumption that all HA-subjects show a constant attentional bias. Current models distinguish HA-subjects depending on their level of tolerance for uncertainty and for arousal. These models assume that only HA-subjects with intolerance for uncertainty but tolerance for arousal (“sensitizers”) show an attentional bias, compared to HA-subjects with intolerance for uncertainty and intolerance for arousal (“fluctuating subjects”). Further, it is assumed that repressors (defined as intolerance for arousal but tolerance for uncertainty) would react with avoidance behavior when confronted with threatening stimuli. The present study investigated the influence of coping styles on attentional bias. After an extensive recruiting phase, 36 subjects were classified into three groups (sensitizers, fluctuating, and repressors). All subjects were exposed to presentations of happy and threatening faces, while recording gaze durations with an eye-tracker. The results showed that only sensitizer showed an attentional bias: they gazed longer at the threatening face rather than at the happy face during the first 500 ms. The results support the findings of the relationship between anxiety and attention and extend these by showing variations according to coping styles. The differentiation of subjects according to a multifaceted coping style allows a better prediction of the attentional bias and contributes to an insight into the complex interplay of personality, coping, and behavior. PMID:21085590

Klucken, Tim; Brouwer, Anne-Marie; Chatziastros, Astros; Kagerer, Sabine; Netter, Petra; Hennig, Juergen

2010-01-01

218

Chronic postweaning lead exposure and response duration performance  

SciTech Connect

Twenty-one-day-old male weanling rats were started on a chronic exposure regimen of 0, 100, or 300 ppm lead acetate in distilled water. They were trained to press a lever for food reward at 55 days of age. Subsequently, a schedule of differential reinforcement of minimum response duration was imposed, in which only lever press durations greater than or equal to a required duration were followed by food presentation. Under these conditions, response durations of control animals approximated schedule requirements; lead treatment shortened response durations. Treated rats also paused for longer periods before initiating responses. Differences between the treated groups were not apparent. Individual differences were observed in susceptibility to lead-induced behavioral changes. Some treated animals tended to show greater session-to-session variability than did controls. Even when a tone was added to signal that the required duration had elapsed, certain treated rats failed to show modal response duration values consistent with the schedule requirement. Failure to improve performance of lead-treated rats by external stimulus control has not previously been reported.

Cory-Slechta, D. (Univ. of Rochester, NY); Bissen, S.T.; Young, A.M.; Thompson, T.

1981-01-01

219

Short Sleep Duration and Adiposity in Chinese Adolescents  

PubMed Central

Objective: To investigate the relationship between sleep duration and adiposity measurements in rural Chinese adolescents. Methods: This report is based on a cross-sectional analysis of 500 Chinese adolescent twins. Anthropometric measurements and direct adiposity measurements using dual-energy X-ray absorptiometry (DEXA) were taken for all subjects. Standard sleep questionnaires and a 7-day diary were administered to assess sleep duration. Results: Sleep duration decreased with increasing age during adolescence, reaching a nadir at approximately 15 years of age. While BMI and body fat increased through the entire range of adolescence for both genders, after the age of 12, females had much higher amounts of total and truncal fat than males. Graphic plots showed that among females, both long and short sleepers tended to have higher adiposity measures than medium duration sleepers. The association of short sleep duration with higher adiposity measures was significant even after adjustment for covariates. This association was stronger for total and truncal fat and waist circumference (P <0.05) than for BMI (P = 0.06). In contrast, consistent relationships between sleep duration and adiposity measures were not seen in males. Conclusion: Even in this relatively lean Chinese adolescent cohort, short sleep duration was significantly associated with higher adiposity measures and lower lean body mass in females. The results of this study indicate that the observed association between short sleep duration and higher BMI is most likely mediated by factors associated with total and central adiposity rather than lean body mass. Citation: Yu Y; Lu BS; Wang B; Wang H; Yang J. Short sleep duration and adiposity in chinese adolescents. SLEEP 2007;30(12):1688-1697. PMID:18246978

Yu, Yunxian; Lu, Brandon S.; Wang, Binyan; Wang, Hongjian; Yang, Jianhua; Li, Zhiping; Wang, Liuliu; Liu, Xue; Tang, Genfu; Xing, Houxun; Xu, Xiping; Zee, Phyllis C.; Wang, Xiaobin

2007-01-01

220

Epicardial ECG signals following global myocardial ischaemia  

Microsoft Academic Search

Summary Experiments were performed on 10 dog hearts undergone 15 to 90-minute normothermic arrests and 60-minute reperfusion in a special heart-lung model. The purpose of the experiments was to characterize the global ischaemic effects recorded on epicardial electrograms. The duration of QRS complexes and of RR intervals, the integral of ST segment shifts (?ST), the number of points showed ST

B. Török; E. Röth; B. Mezey; S. Szabados; T. Simor

1983-01-01

221

Bayesian Hierarchical Duration Model for Repeated Events : An Application to Behavioral Observations  

PubMed Central

This paper presents a continuous-time Bayesian model for analyzing durations of behavior displays in social interactions. Duration data of social interactions are often complex because of repeated behaviors (events) at individual or group (e.g., dyad) level, multiple behaviors (multistates), and several choices of exit from a current event (competing risks). A multilevel, multistate model is proposed to adequately characterize the behavioral processes. The model incorporates dyad-specific and transition-specific random effects to account for heterogeneity among dyads and interdependence among competing risks. The proposed method is applied to child-parent observational data derived from the School Transitions Project to assess the relation of emotional expression in child-parent interaction to risk for early and persisting child conduct problems. PMID:20209032

Dagne, Getachew A.; Snyder, James

2009-01-01

222

Crossover from weak to strong disorder regime in the duration of epidemics  

NASA Astrophysics Data System (ADS)

We study the susceptible-infected-recovered (SIR) model in complex networks, considering that not all individuals in the population interact in the same way. This heterogeneity between contacts is modeled by a continuous disorder. In our model, the disorder represents the contact time or the closeness between individuals. We find that the duration time of an epidemic has a crossover with the system size, from a power-law regime to a logarithmic regime depending on the transmissibility related to the strength of the disorder. Using percolation theory, we find that the duration of the epidemic scales as the average length of the branches of the infection. Our theoretical findings, supported by simulations, explains the crossover between the two regimes.

Buono, C.; Lagorio, C.; Macri, P. A.; Braunstein, L. A.

2012-08-01

223

10 CFR 52.104 - Duration of combined license.  

...Section 52.104 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Combined Licenses § 52.104 Duration of combined license. A combined license is issued for a...

2014-01-01

224

10 CFR 52.55 - Duration of certification.  

Code of Federal Regulations, 2012 CFR

...Section 52.55 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Standard Design Certifications § 52.55 Duration of certification. (a) Except as provided...

2012-01-01

225

10 CFR 52.147 - Duration of design approval.  

Code of Federal Regulations, 2013 CFR

...Section 52.147 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Standard Design Approvals § 52.147 Duration of design approval. A standard design approval...

2013-01-01

226

10 CFR 52.181 - Duration of renewal.  

...Section 52.181 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Manufacturing Licenses § 52.181 Duration of renewal. A renewed manufacturing license may be...

2014-01-01

227

10 CFR 52.173 - Duration of manufacturing license.  

Code of Federal Regulations, 2013 CFR

...Section 52.173 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Manufacturing Licenses § 52.173 Duration of manufacturing license. A manufacturing license...

2013-01-01

228

10 CFR 52.104 - Duration of combined license.  

Code of Federal Regulations, 2013 CFR

...Section 52.104 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Combined Licenses § 52.104 Duration of combined license. A combined license is issued for a...

2013-01-01

229

10 CFR 52.26 - Duration of permit.  

Code of Federal Regulations, 2013 CFR

...Section 52.26 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Early Site Permits § 52.26 Duration of permit. (a) Except as provided in paragraph (b)...

2013-01-01

230

10 CFR 52.173 - Duration of manufacturing license.  

...Section 52.173 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Manufacturing Licenses § 52.173 Duration of manufacturing license. A manufacturing license...

2014-01-01

231

10 CFR 52.55 - Duration of certification.  

Code of Federal Regulations, 2011 CFR

...Section 52.55 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Standard Design Certifications § 52.55 Duration of certification. (a) Except as provided...

2011-01-01

232

10 CFR 52.181 - Duration of renewal.  

Code of Federal Regulations, 2012 CFR

...Section 52.181 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Manufacturing Licenses § 52.181 Duration of renewal. A renewed manufacturing license may be...

2012-01-01

233

10 CFR 52.61 - Duration of renewal.  

Code of Federal Regulations, 2013 CFR

...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 renewal of certification for a...

2013-01-01

234

10 CFR 52.26 - Duration of permit.  

...Section 52.26 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Early Site Permits § 52.26 Duration of permit. (a) Except as provided in paragraph (b)...

2014-01-01

235

10 CFR 52.61 - Duration of renewal.  

Code of Federal Regulations, 2012 CFR

...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 renewal of certification for a...

2012-01-01

236

Medical studies and training duration for forensic pathologists in Germany.  

PubMed

This article gives a short overview of medical education in Germany. The legal basis and organization of the medical studies program as well as the course in forensic medicine and the training duration for forensic pathologists are described. PMID:12935530

Bockholdt, B; Rothschild, M A; Ehrlich, E; Maxeiner, H; Schneider, V

2001-06-01

237

10 CFR 451.6 - Duration of incentive payments.  

Code of Federal Regulations, 2010 CFR

...Section 451.6 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION RENEWABLE ENERGY PRODUCTION INCENTIVES § 451.6 Duration...payments under this part with respect to a qualified renewable energy facility for 10 consecutive fiscal...

2010-01-01

238

Sleep Duration Linked to Ulcerative Colitis Risk in Study  

MedlinePLUS

... sharing features on this page, please enable JavaScript. Sleep Duration Linked to Ulcerative Colitis Risk in Study ... Dallas Friday, October 24, 2014 Related MedlinePlus Pages Sleep Disorders Ulcerative Colitis FRIDAY, Oct. 24, 2014 (HealthDay ...

239

Volume-Duration-Frequencies for Ungaged Catchments in Texas  

E-print Network

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...

Devulapalli, Ravi S.; Valdes, Juan B.

240

Short-duration Radio Bursts with Apparent Extragalactic Dispersion  

E-print Network

We present the results of the longest yet undertaken search for apparently extragalactic radio bursts at the Bleien Radio Observatory covering 21000 hours (898 days). The data were searched for events of less than 50 ms FWHM duration showing a $\

Saint-Hilaire, Pascal; Monstein, Christian

2014-01-01

241

42 CFR 61.13 - Duration and continuation.  

Code of Federal Regulations, 2011 CFR

...13 Section 61.13 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING FELLOWSHIPS Regular Fellowships § 61.13 Duration and continuation. An award period may be any...

2011-10-01

242

42 CFR 61.13 - Duration and continuation.  

Code of Federal Regulations, 2012 CFR

...13 Section 61.13 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING FELLOWSHIPS Regular Fellowships § 61.13 Duration and continuation. An award period may be any...

2012-10-01

243

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...

2010-10-01

244

5 CFR 1312.6 - Duration of classification.  

Code of Federal Regulations, 2010 CFR

...under Executive Order 12958, an original classification authority shall...standards for classification under the Executive Order. (3) Make...a duration of classification consistent with the Executive Order. (iii)...

2010-01-01

245

15 CFR 4a.5 - Duration of classification.  

Code of Federal Regulations, 2010 CFR

...the date of its original classification, except as provided...an indefinite duration of classification under predecessor orders to E.O. 12958 shall...the date of its original classification, except as provided...

2010-01-01

246

32 CFR 2001.12 - Duration of classification.  

Code of Federal Regulations, 2011 CFR

...classified under the Order. Extensions of classification are not automatic...the standards for classification under the Order; and (iii) Make...indefinite duration of classification under a prior order; or in those...

2011-07-01

247

15 CFR 4a.5 - Duration of classification.  

Code of Federal Regulations, 2011 CFR

...the date of its original classification, except as provided...an indefinite duration of classification under predecessor orders to E.O. 12958 shall...the date of its original classification, except as provided...

2011-01-01

248

32 CFR 2001.12 - Duration of classification.  

Code of Federal Regulations, 2010 CFR

...classified under the Order. Extensions of classification are not automatic...the standards for classification under the Order; and (iii) Make...indefinite duration of classification under a prior order; or in those...

2010-07-01

249

5 CFR 1312.6 - Duration of classification.  

Code of Federal Regulations, 2011 CFR

...under Executive Order 12958, an original classification authority shall...standards for classification under the Executive Order. (3) Make...a duration of classification consistent with the Executive Order. (iii)...

2011-01-01

250

7 CFR 989.88 - Duration of immunities.  

Code of Federal Regulations, 2011 CFR

...MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN IN CALIFORNIA Order Regulating Handling Miscellaneous Provisions § 989.88 Duration of immunities. The...

2011-01-01

251

Vocal Corollary Discharge Communicates Call Duration to Vertebrate Auditory System  

PubMed Central

Corollary discharge is essential to an animal's ability to filter self-generated from external stimuli. This includes acoustic communication, although direct demonstration of a corollary discharge that both conveys a vocal motor signal and informs the auditory system about the physical attributes of a self-generated vocalization has remained elusive for vertebrates. Here, we show the underlying synaptic activity of a neuronal vocal corollary discharge pathway in the hindbrain of a highly vocal species of fish. Neurons carrying the vocal corollary discharge are specifically adapted for the transmission of duration information, a predominant acoustic cue. The results reveal that vertebrates, like some insects, have a robust corollary discharge conveying call duration. Along with evidence for the influence of vocal duration on auditory encoding in mammals, these new findings suggest that linking vocal motor and corollary discharge pathways with pattern generating, call duration neurons is a shared network character across the animal kingdom. PMID:24285884

2013-01-01

252

Capturing Breathy Voice: Durational Measures of Oral Stops in Marathi  

E-print Network

The present study investigates a series of techniques used to capture the durational differences of oral stops in Marathi, an Indic language that exhibits a four-way phonemic distinction among oral stops.

Berkson, Kelly Harper

2012-12-11

253

36 CFR 72.33 - Timing and duration of projects.  

Code of Federal Regulations, 2011 CFR

...Program Development, Rehabilitation and Innovation § 72.33 Timing and duration of...components of either Rehabilitation or Innovation proposals will be limited to three...federal government. Any component of an Innovation proposal which is to provide...

2011-07-01

254

36 CFR 72.33 - Timing and duration of projects.  

Code of Federal Regulations, 2010 CFR

...Program Development, Rehabilitation and Innovation § 72.33 Timing and duration of...components of either Rehabilitation or Innovation proposals will be limited to three...federal government. Any component of an Innovation proposal which is to provide...

2010-07-01

255

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...

2012-01-01

256

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...

2013-01-01

257

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...

2010-01-01

258

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...

2011-01-01

259

7 CFR 917.65 - Duration of immunities.  

Code of Federal Regulations, 2010 CFR

...MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN CALIFORNIA Order Regulating Handling Miscellaneous Provisions § 917.65 Duration of immunities. The...

2010-01-01

260

7 CFR 917.65 - Duration of immunities.  

Code of Federal Regulations, 2011 CFR

...MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN CALIFORNIA Order Regulating Handling Miscellaneous Provisions § 917.65 Duration of immunities. The...

2011-01-01

261

46 CFR 71.75-20 - Duration of certificates.  

Code of Federal Regulations, 2010 CFR

...PASSENGER VESSELS INSPECTION AND CERTIFICATION Certificates Under the International Convention for Safety of Life at Sea, 1960 § 71.75-20 Duration of certificates. (a) The certificates are issued for a period of not more than 12...

2010-10-01

262

7 CFR 1450.205 - Duration of contracts.  

Code of Federal Regulations, 2011 CFR

...Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS BIOMASS CROP ASSISTANCE PROGRAM (BCAP) Establishment Payments and Annual Payments § 1450.205 Duration of contracts....

2011-01-01

263

7 CFR 1450.205 - Duration of contracts.  

Code of Federal Regulations, 2012 CFR

...Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS BIOMASS CROP ASSISTANCE PROGRAM (BCAP) Establishment Payments and Annual Payments § 1450.205 Duration of contracts....

2012-01-01

264

7 CFR 1450.205 - Duration of contracts.  

Code of Federal Regulations, 2013 CFR

...Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS BIOMASS CROP ASSISTANCE PROGRAM (BCAP) Establishment Payments and Annual Payments § 1450.205 Duration of contracts....

2013-01-01

265

7 CFR 3430.709 - Duration of awards.  

Code of Federal Regulations, 2013 CFR

...AGRICULTURE COMPETITIVE AND NONCOMPETITIVE NON-FORMULA FEDERAL ASSISTANCE PROGRAMS-GENERAL AWARD ADMINISTRATIVE PROVISIONS Biomass Research and Development Initiative § 3430.709 Duration of awards. The term of a Federal assistance award made...

2013-01-01

266

7 CFR 3430.709 - Duration of awards.  

Code of Federal Regulations, 2011 CFR

...AGRICULTURE COMPETITIVE AND NONCOMPETITIVE NON-FORMULA FEDERAL ASSISTANCE PROGRAMS-GENERAL AWARD ADMINISTRATIVE PROVISIONS Biomass Research and Development Initiative § 3430.709 Duration of awards. The term of a Federal assistance award made...

2011-01-01

267

7 CFR 3430.709 - Duration of awards.  

Code of Federal Regulations, 2012 CFR

...AGRICULTURE COMPETITIVE AND NONCOMPETITIVE NON-FORMULA FEDERAL ASSISTANCE PROGRAMS-GENERAL AWARD ADMINISTRATIVE PROVISIONS Biomass Research and Development Initiative § 3430.709 Duration of awards. The term of a Federal assistance award made...

2012-01-01

268

7 CFR 3430.709 - Duration of awards.  

...AGRICULTURE COMPETITIVE AND NONCOMPETITIVE NON-FORMULA FEDERAL ASSISTANCE PROGRAMS-GENERAL AWARD ADMINISTRATIVE PROVISIONS Biomass Research and Development Initiative § 3430.709 Duration of awards. The term of a Federal assistance award made...

2014-01-01

269

7 CFR 1450.205 - Duration of contracts.  

...Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS BIOMASS CROP ASSISTANCE PROGRAM (BCAP) Establishment Payments and Annual Payments § 1450.205 Duration of contracts....

2014-01-01

270

7 CFR 985.69 - Duration of immunities.  

...AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE MARKETING ORDER REGULATING THE HANDLING OF SPEARMINT OIL PRODUCED IN THE FAR WEST Order Regulating Handling Miscellaneous Provisions § 985.69 Duration of...

2014-01-01

271

7 CFR 985.69 - Duration of immunities.  

Code of Federal Regulations, 2010 CFR

...Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE MARKETING ORDER REGULATING THE HANDLING OF SPEARMINT OIL PRODUCED IN THE FAR WEST Order Regulating Handling Miscellaneous Provisions § 985.69 Duration of...

2010-01-01

272

7 CFR 985.69 - Duration of immunities.  

Code of Federal Regulations, 2013 CFR

...AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE MARKETING ORDER REGULATING THE HANDLING OF SPEARMINT OIL PRODUCED IN THE FAR WEST Order Regulating Handling Miscellaneous Provisions § 985.69 Duration of...

2013-01-01

273

7 CFR 985.69 - Duration of immunities.  

Code of Federal Regulations, 2012 CFR

...Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE MARKETING ORDER REGULATING THE HANDLING OF SPEARMINT OIL PRODUCED IN THE FAR WEST Order Regulating Handling Miscellaneous Provisions § 985.69 Duration of...

2012-01-01

274

7 CFR 985.69 - Duration of immunities.  

Code of Federal Regulations, 2011 CFR

...Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE MARKETING ORDER REGULATING THE HANDLING OF SPEARMINT OIL PRODUCED IN THE FAR WEST Order Regulating Handling Miscellaneous Provisions § 985.69 Duration of...

2011-01-01

275

Improving Prediction of Surgery Duration using Operational and Temporal Factors  

PubMed Central

Inherent uncertainties in surgery durations impact many critical metrics about the performance of an operating room (OR) environment. OR schedules that are robust to natural variability in surgery durations require surgery duration estimates that are unbiased, with high accuracy, and with few cases with large absolute errors. Earlier studies have shown that factors such as patient severity, personnel, and procedure type greatly affect the accuracy of such estimations. In this paper we investigate whether operational and temporal factors can be used to improve these estimates further. We present an adjustment method based on a combination of these operational and temporal factors. We validate our method with two years of detailed operational data from an electronic medical record. We conclude that while improving estimates of surgery durations is possible, the inherent variability in such estimates remains high, necessitating caution in their use when optimizing OR schedules. PMID:23304316

Kayis, Enis; Wang, Haiyan; Patel, Meghna; Gonzalez, Tere; Jain, Shelen; Ramamurthi, RJ; Santos, Cipriano; Singhal, Sharad; Suermondt, Jaap; Sylvester, Karl

2012-01-01

276

Effect of measurement duration on accuracy of pulse-counting.  

PubMed

In this study, the relation between the measurement duration and accuracy of pulse-counting was quantitatively examined with special reference to low-frequency fluctuations in heart rate variability. The interbeat intervals of 70 healthy male subjects were measured in standing, sitting and supine positions. Pulse rates for various durations were calculated by objective-scoring simulation based on the heartbeat recordings of the subjects. The duration of pulse-counting continuously varied from 6 to 60 s in the simulation. Simulated pulse rates were compared with the rate calculated from the 60 s that includes the given duration, and the absolute difference between the two rates was defined as the error. Average errors of pulse-counting for 15 s were 1.89, 1.89 and 1.80 bpm for standing, sitting and supine positions, respectively. No difference in error was observed between standing and sitting positions; however, smaller errors were observed in the supine position. PMID:24117167

Kobayashi, Hiromitsu

2013-01-01

277

38 CFR 60.7 - Duration of temporary lodging.  

Code of Federal Regulations, 2012 CFR

...examinations provided at a VA health care facility. When a veteran is undergoing extensive treatment or procedures, such as an organ transplant or chemotherapy, eligible persons may be furnished temporary lodging for the duration of the episode of care...

2012-07-01

278

38 CFR 60.7 - Duration of temporary lodging.  

Code of Federal Regulations, 2011 CFR

...examinations provided at a VA health care facility. When a veteran is undergoing extensive treatment or procedures, such as an organ transplant or chemotherapy, eligible persons may be furnished temporary lodging for the duration of the episode of care...

2011-07-01

279

42 CFR 61.13 - Duration and continuation.  

Code of Federal Regulations, 2013 CFR

...13 Section 61.13 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING FELLOWSHIPS Regular Fellowships § 61.13 Duration and continuation. An award period may be any...

2013-10-01

280

7 CFR 906.58 - Duration of immunities.  

Code of Federal Regulations, 2010 CFR

...Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ORANGES AND GRAPEFRUIT GROWN IN LOWER RIO GRANDE VALLEY IN TEXAS Order Regulating Handling Miscellaneous Provisions § 906.58 Duration of immunities. The...

2010-01-01

281

38 CFR 21.73 - Duration of employment assistance programs.  

... Pensions, Bonuses, and Veterans' Relief 2 2014-07-01...2014-07-01 false Duration of employment assistance programs. 21... Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS (CONTINUED)...

2014-07-01

282

Performance and alertness of railroad engineers on long duration trips  

E-print Network

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 ...

Karnali, Leona D., 1978-

2004-01-01

283

7 CFR 930.86 - Duration of immunities.  

...VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE TART CHERRIES GROWN IN THE STATES OF MICHIGAN, NEW YORK, PENNSYLVANIA, OREGON, UTAH, WASHINGTON, AND WISCONSIN Order Regulating Handling Miscellaneous Provisions § 930.86 Duration of...

2014-01-01

284

5 CFR 352.704 - Duration of reemployment rights.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Duration of reemployment rights. 352.704 Section 352.704 Administrative...MANAGEMENT CIVIL SERVICE REGULATIONS REEMPLOYMENT RIGHTS Reemployment Rights of Former Bureau of Indian Affairs and...

2010-01-01

285

7 CFR 3430.1011 - Duration of awards.  

...FEDERAL ASSISTANCE PROGRAMS-GENERAL AWARD ADMINISTRATIVE PROVISIONS Sun Grant Program § 3430.1011 Duration of awards. The term of a Federal assistance award made under the Sun Grant Program shall not exceed 5 years. No-cost extensions of...

2014-01-01

286

7 CFR 3430.1011 - Duration of awards.  

Code of Federal Regulations, 2013 CFR

...FEDERAL ASSISTANCE PROGRAMS-GENERAL AWARD ADMINISTRATIVE PROVISIONS Sun Grant Program § 3430.1011 Duration of awards. The term of a Federal assistance award made under the Sun Grant Program shall not exceed 5 years. No-cost extensions of...

2013-01-01

287

7 CFR 3430.1011 - Duration of awards.  

Code of Federal Regulations, 2012 CFR

...FEDERAL ASSISTANCE PROGRAMS-GENERAL AWARD ADMINISTRATIVE PROVISIONS Sun Grant Program § 3430.1011 Duration of awards. The term of a Federal assistance award made under the Sun Grant Program shall not exceed 5 years. No-cost extensions of...

2012-01-01

288

7 CFR 3430.1011 - Duration of awards.  

Code of Federal Regulations, 2011 CFR

...FEDERAL ASSISTANCE PROGRAMS-GENERAL AWARD ADMINISTRATIVE PROVISIONS Sun Grant Program § 3430.1011 Duration of awards. The term of a Federal assistance award made under the Sun Grant Program shall not exceed 5 years. No-cost extensions of...

2011-01-01

289

38 CFR 60.7 - Duration of temporary lodging.  

Code of Federal Regulations, 2010 CFR

...60.7 Section 60.7 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS (CONTINUED) FISHER HOUSES AND OTHER TEMPORARY LODGING § 60.7 Duration of temporary lodging. Temporary lodging may be furnished to...

2010-07-01

290

Duration of Sleep and ADHD Tendency Among Adolescents in China  

Microsoft Academic Search

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 of sleep is measured by self-reported time to bed and rise.

Lawrence T. Lam; L. Yang

2008-01-01

291

Sucking and allosucking duration in farmed red deer ( Cervus elaphus)  

Microsoft Academic Search

Sucking duration in ungulates does not only mean milk transfer, but is also associated with maternal care in general. It seems to be a reflection of offspring demand rather than solely milk transfer rate. Thus, the objective of this study was to discriminate between sucking and allosucking (i.e. sucking non-maternal hind) behaviour in red deer according to the sucking duration.We

Jorga Drabkovaa; Jitka Bartošová; Lud?k Bartoš; Radim Kotrba; Jan Pluhá?ek; Ludmila Švecová; Adam Dušek; Tomáš Kott

2008-01-01

292

Particle Astrophysics in NASA's Long Duration Balloon Program  

E-print Network

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.

Gorham, Peter W

2013-01-01

293

Component duration and relative response rates in multiple schedules.  

NASA Technical Reports Server (NTRS)

Pigeons were trained on a multiple variable-interval 30-sec, variable interval 90-sec schedule with each component presented alternately for an equal duration. This duration of exposure was varied from 5 to 300 sec. The rate of response in the variable-interval 30-sec component relative to the rate of response in the variable-interval 90-sec component was studied. Results are plotted and discussed.

Todorov, J. C.

1972-01-01

294

Strategies for crew selection for long duration missions  

NASA Technical Reports Server (NTRS)

Issues surrounding psychological reactions to long duration spaceflight are discussed with respect to the definition of criteria for selecting crewmembers for such expeditions. Two broad dimensions of personality and behavior are defined - Instrumentality including achievement orientation, leadership, and ability to perform under pressure and Expressivity encompassing interpersonal sensitivity and competence. A strategy for validating techniques to select in candidates with the optimum psychological profile to perform successfully on long duration missions is described.

Helmreich, Robert L.; Holland, Albert W.; Santy, Patricia A.; Rose, Robert M.; Mcfadden, Terry J.

1990-01-01

295

Objective sleep duration and health in elderly Russians  

Microsoft Academic Search

Objectives - We examine the relationship between sleep duration and health in the high mortality context of Russia. Methods - Night and daytime sleep durations are based on self-reports and 24-hour heart rate trends (Holter monitoring). The sample of 201 individuals (Holter data for 185) is drawn from the Moscow Lipid Research Clinics cohort, followed up since 1975-77. Field-work occurred

Maria A. Shkolnikova; Blake Aber; Maxine Weinstein; Luobov´ Kravtsova; Svetlana A. Shalnova; Vladimir M. Shkolnikov; James W. Vaupel

2006-01-01

296

Procedures used for assessment of stuttering frequency and stuttering duration.  

PubMed

Frequency of stuttered syllables and their durations were assessed using different procedures. The experiment examined overall syllable counts, counts of stuttered syllables and measures of stutter durations when they were made simultaneously or successively. Samples of speech with associated syllable, stuttered syllable and duration measurements of stuttering events were employed in reference transcriptions. Samples contained a minimum of 200 syllables. Ten participants assessed these samples for syllables, stuttered syllables and duration in an experiment. The responses of these participants were stored in alignment with the speech recordings for analysis. Performance was significantly more accurate (relative to transcriptions) for measures other than duration when the successive procedure was used as opposed to the simultaneous procedure. Although the successive method was more accurate, accuracy of stutter event identification was low for most participants. The procedure that allowed listeners to replay a speech sample and count the syllables, stuttered syllables and durations in three passes yielded more accurate syllable and stuttered syllable counts than procedures that required these judgments to be made in one pass. PMID:23848369

Jani, Leanne; Huckvale, Mark; Howell, Peter

2013-12-01

297

50 W thin-disk laser with variable pulse duration  

NASA Astrophysics Data System (ADS)

The laser system is based on an Yb:YAG thin-disk regenerative amplifier, which is operated in different operation modes in order to address broad spectrum of pulse durations. It is especially interesting for application development tasks, when different pulse durations can be tested to find the application optimum. For sub-picosecond pulse duration the dispersion of the regenerative amplifier output is compensated with a pair of diffraction gratings. Pulses with a full width at half maximum of 334 fs at an output power level of 30 W can be produced using a nonlinear spectrum broadening during amplification. Tuning of the distance between gratings or abandoning of the compressor allows for output pulse durations of several picoseconds with an output power of 60 W. A second seed source allows for pulse durations up to several nanoseconds. Further, the amplifier was operated in cavity-dumped or in Q-switched mode just by changing of the electrical control of the Pockels cell in the amplifier. The pulse durations range is extended, correspondingly, to 100 ns and even to microseconds.

Larionov, Mikhail; Dausinger, Friedrich

2011-02-01

298

Effects of stimulus duration on audio-visual synchrony perception.  

PubMed

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

Kuling, I A; van Eijk, R L J; Juola, J F; Kohlrausch, A

2012-09-01

299

Asymmetric processing of durational differences - electrophysiological investigations in Bengali.  

PubMed

Duration is used contrastively in many languages to distinguish word meaning (e.g. in Bengali, [pata] 'leaf' vs. [pat:a] 'whereabouts'). While there is a large body of research on other contrasts in speech perception (e.g. vowel contrasts and consonantal place features), little work has been done on how durational information is used in speech processing. In non-linguistic studies of low-level processing, such as visual and non-linguistic acoustic pop-out tasks, an asymmetry is found where additional information is more readily detected than missing information. In this study, event-related potentials were recorded during two cross-modal auditory-visual semantic priming studies, where nonword mispronunciations of spoken prime words were created by changing the duration of a medial consonant (real word [dana] 'seed'>nonword [dan:a]). N400 amplitudes showed an opposite asymmetric pattern of results, where increases in consonantal duration were tolerated and led to priming of the visual target, but decreases in consonantal duration were not accepted. This asymmetrical pattern of acceptability is attributed to the fact that a longer consonant includes all essential information for the recognition of the original word with a short medial consonant (a possible default category) and any additional information can be ignored. However, when a consonant is shortened, it lacks the required durational information to activate the word with the original long consonant. PMID:24726333

Roberts, Adam C; Kotzor, Sandra; Wetterlin, Allison; Lahiri, Aditi

2014-05-01

300

Insomnia with Short Sleep Duration: Nosological, Diagnostic, and Treatment Implications  

PubMed Central

The diagnosis of insomnia is based solely on subjective complaints. This has contributed to the low reliability and validity of the current nosology of insomnia as well as to its lack of firm association with clinically relevant outcomes such as cardiometabolic and neurocognitive morbidity. We review evidence that insomnia with objective short sleep duration is associated with physiological hyperarousal, higher risk for hypertension, diabetes, neurocognitive impairment, and mortality as well as with a persistent course. It also appears that objective short sleep duration in poor sleepers is a biological marker of genetic predisposition to chronic insomnia. In contrast, insomnia with objective normal sleep duration is associated with cognitive-emotional and cortical arousal and sleep misperception but not with signs of physiological hyperarousal or medical complications. Thus, short sleep duration in insomnia may be a reliable marker of the biological severity and medical impact of the disorder. We propose that (a) objective measures of sleep be included in the diagnosis of insomnia and its subtypes, (b) objective measures of sleep obtained in the home environment of the patient would become part of the routine assessment and diagnosis of insomnia in a clinician’s office setting, and (c) insomnia with short sleep duration may respond better to biological treatments, whereas insomnia with normal sleep duration may respond primarily to psychological therapies. PMID:24072989

Vgontzas, Alexandros N.; Fernandez-Mendoza, Julio

2013-01-01

301

Depth-Duration Frequency of Precipitation for Oklahoma  

USGS Publications Warehouse

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.

Tortorelli, Robert L.; Rea, Alan; Asquith, William H.

1999-01-01

302

Note: Measurement of extreme-short current pulse duration of runaway electron beam in atmospheric pressure air  

SciTech Connect

This note reports the time-amplitude characteristic of the supershort avalanche electron beam with up to 20 ps time resolution. For the first time it is shown that the electron beam downstream of small-diameter diaphragms in atmospheric pressure air has a complex structure which depends on the interelectrode gap width and cathode design. With a spherical cathode and collimator the minimum duration at half maximum of the supershort avalanche electron beam current pulse was shown to be {approx}25 ps. The minimum duration at half maximum of one peak in the pulses with two peaks can reach {approx}25 ps too.

Tarasenko, V. F.; Rybka, D. V.; Burachenko, A. G.; Lomaev, M. I.; Balzovsky, E. V. [Institute of High Current Electronics SB RAS, 2/3 Akademichesky Ave., 634055 Tomsk (Russian Federation)

2012-08-15

303

Association between sleep duration and blood pressure in adolescents.  

PubMed

In adults, sleep has an important role in the development of cardiovascular diseases. However, in young adolescents, the effect is unclear. The purpose of this cross-sectional study was to evaluate the association between sleep duration and blood pressure (BP) in subjects of 13 years of age. We evaluated 1771 adolescents as part of a population-based cohort (Epidemiological Health Investigation of Teenagers). Sleep duration was estimated based on the difference between self-reported usual bedtimes and wake-up times, and adolescents were classified into three categories: ?8.5?h (reference class), >8.5?h and <9.5?h, and ?9.5?h. BP was measured using the auscultatory method and was classified as high if the systolic or diastolic BP was ?90th percentile according to the American Academy of Pediatrics. To evaluate the association between BP and sleep duration, the odds ratios (ORs) and 95% confidence intervals (95% CIs) were computed by fitting binary logistic regression models with adjustments for caffeine intake and depressive symptoms in females and for caffeine intake and sports activities in males. The mean (s.d.) sleep duration was 9.0 (0.80)?h per day. The prevalence of high BP was 32.5%, higher in males (35.3%) than in females (30.1%, P=0.019). After adjustment, in females, a positive association was found between sleep duration and high BP (>8.5 and <9.5?h: OR=1.56, 95% CI 1.07-2.27; ?9.5?h: OR=1.83, 95% CI 1.23-2.70). Among males, no significant association was found between sleep duration and BP. Sleep duration was positively associated with BP in both sexes, although after adjustment for potential confounders, this association was significant only for female adolescents. PMID:23595048

Paciência, Inês; Barros, Henrique; Araújo, Joana; Ramos, Elisabete

2013-08-01

304

Effect of measurement duration on accuracy of pulse-counting  

PubMed Central

In this study, the relation between the measurement duration and accuracy of pulse-counting was quantitatively examined with special reference to low-frequency fluctuations in heart rate variability. The interbeat intervals of 70 healthy male subjects were measured in standing, sitting and supine positions. Pulse rates for various durations were calculated by objective-scoring simulation based on the heartbeat recordings of the subjects. The duration of pulse-counting continuously varied from 6 to 60 s in the simulation. Simulated pulse rates were compared with the rate calculated from the 60 s that includes the given duration, and the absolute difference between the two rates was defined as the error. Average errors of pulse-counting for 15 s were 1.89, 1.89 and 1.80 bpm for standing, sitting and supine positions, respectively. No difference in error was observed between standing and sitting positions; however, smaller errors were observed in the supine position. Practitioner Summary: This study provides information on the degree of error that will occur when pulse rates are objectively scored for various durations, for example 10, 15 or 30 s, instead of a full minute. This useful information may be beneficial for physicians, nurses and medical practitioners. PMID:24117167

Kobayashi, Hiromitsu

2013-01-01

305

Building a Shared Definitional Model of Long Duration Human Spaceflight  

NASA Technical Reports Server (NTRS)

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.

Orr, M.; Whitmire, A.; Sandoval, L.; Leveton, L.; Arias, D.

2011-01-01

306

Effectiveness and duration of intramuscular antimotion sickness medications  

NASA Technical Reports Server (NTRS)

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.

Wood, C. D.; Stewart, J. J.; Wood, M. J.; Mims, M.

1992-01-01

307

Semiparametric modeling of grouped current duration data with preferential reporting.  

PubMed

Current duration data arise in cross-sectional studies from questions on the length of time from an initiating event to the time of interview. For example, in the National Survey on Family Growth, women who were considered at risk for pregnancy were asked (i) 'Are you currently attempting pregnancy?' and (ii) 'If yes, how many months have you been attempting to get pregnant?' The responses to (ii), referred to as the current durations, are length-biased because women with longer durations are more likely to answer yes to question (i) and therefore be included in the sample. Previous methods to analyze such data include continuous time nonparametric and parametric approaches. In this article, we propose a semiparametric Cox model and a piecewise constant baseline model (used to account for digit preference) to analyze grouped current duration data. We discuss and investigate through simulation studies, the robustness properties of the proposed methods when digit preference is present. Lastly, we present an analysis of the current duration data resulting from the 2002 National Survey on Family Growth. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. PMID:24862959

McLain, Alexander C; Sundaram, Rajeshwari; Thoma, Marie; Buck Louis, Germaine M

2014-10-15

308

New method development in prehistoric stone tool research: evaluating use duration and data analysis protocols.  

PubMed

Lithic microwear is a research field of prehistoric stone tool (lithic) analysis that has been developed with the aim to identify how stone tools were used. It has been shown that laser scanning confocal microscopy has the potential to be a useful quantitative tool in the study of prehistoric stone tool function. In this paper, two important lines of inquiry are investigated: (1) whether the texture of worn surfaces is constant under varying durations of tool use, and (2) the development of rapid objective data analysis protocols. This study reports on the attempt to further develop these areas of study and results in a better understanding of the complexities underlying the development of flexible analytical algorithms for surface analysis. The results show that when sampling is optimised, surface texture may be linked to contact material type, independent of use duration. Further research is needed to validate this finding and test an expanded range of contact materials. The use of automated analytical protocols has shown promise but is only reliable if sampling location and scale are defined. Results suggest that the sampling protocol reports on the degree of worn surface invasiveness, complicating the ability to investigate duration related textural characterisation. PMID:25041833

Evans, Adrian A; Macdonald, Danielle A; Giusca, Claudiu L; Leach, Richard K

2014-10-01

309

Long Duration Testing of Type C Thermocouples at 1500 °C  

SciTech Connect

Experience with Type C thermocouples operating for long periods in the 1400 to 1600 °C temperature range indicate that significant decalibration occurs, often leading to expensive downtime and material waste. As part of an effort to understand the mechanisms causing drift in these thermocouples, the Idaho National Laboratory conducted a long duration test at 1500 °C containing eight Type C thermocouples. As report in this document, results from this long duration test were adversely affected due to oxygen ingress. Nevertheless, results provide key insights about the impact of precipitate formation on thermoelectric response. Post-test examinations indicate that thermocouple signal was not adversely impacted by the precipitates detected after 1,000 hours of heating at 1,500 °C and suggest that the signal would not have been adversely impacted by these precipitates for longer durations (if oxygen ingress had not occurred in this test).

Joy L. Rempe; Darrell L. Knudson; J. E. Daw; S. C. Wilkins

2008-04-01

310

Comparison of Postural Recovery Following Short and Long Duration Spaceflights  

NASA Technical Reports Server (NTRS)

INTRODUCTION: Post-flight postural ataxia reflects adaptive changes to vestibulo-spinal reflexes and control strategies adopted for movement in weightlessness. Quantitative measures obtained during computerized dynamic posturography (CDP) from US and Russian programs provide insight into the effect of spaceflight duration in terms of both the initial decrements and recovery of postural stability. METHODS: CDP was obtained on 117 crewmembers following Shuttle flights lasting 4-17 days, and on 64 crewmembers following long-duration missions lasting 48-380 days. Although the number and timing of sessions varied, the goal was to characterize postural recovery pooling similar measures from different research and flight medicine programs. This report focuses on eyes closed, head erect conditions with either a fixed or sway-referenced base of support. A smaller subset of subjects repeated the sway-referenced condition while making pitch head movements (+/- 20deg at 0.33Hz). Equilibrium scores were derived from peak-to-peak anterior-posterior sway. Fall probability was modeled using Bayesian statistical methods to estimate parameters of a logit function. RESULTS: The standard Romberg condition was the least sensitive. Longer duration flights led to larger decrements in stability with sway-reference support during the first 1-2 days, although the timecourse of recovery was similar across flight duration with head erect. Head movements led to increased incidence of falls during the first week, with a significantly longer recovery following long duration flights. CONCLUSIONS: The diagnostic assessment of postural instability, and differences in the timecourse of postural recovery between short and long flight durations, are more pronounced during unstable support conditions requiring active head movements.

Wood, S. J.; Fiedler, J.; Taylor, L. C.; Kozlovskaya, I.; Black, F. O.; Paloski, W. H.

2010-01-01

311

Neuronal plasticity in relation to long-duration spaceflight  

NASA Technical Reports Server (NTRS)

Exposure to microgravity leads to a marked reduction in sensory-motor stimuli to the vestibular, proprioceptive and somatosensory systems. Long-duration missions, such as those proposed for a trip to Mars, may lead to significant changes in neural function. This paper presents results based on studies of sensory deafferentation of specific brain regions and detailed changes which occur in neuronal architecture. Data from these studies emphasize the need for further research related to sensory system deprivation and the development of new unique countermeasures for long-duration space flight.

Hillman, Dean E.; Wolfe, James W.

1990-01-01

312

Introduction to duration concepts: application to bank management  

E-print Network

. 2 Appendix C Table C. l Table 0. 2 Appendix D Table D. l Table D. 2 Table D. 3 Initial Balance Sheet. Analysis of Initial Balance Sheet Accounts Projected Annual Income Statement. Summary Accounts Initial Balance Sheet with a Capital.../Asset Duration Gap 1. 00 Years. . ~ Analysis of Initial Balance Sheet Accounts Analysis of Accounts Adjustments During Six Periods of Interest Rate Changes 32 32 33 33 34 34 34 Table D. 4 Initial Balance Sheet with a Capital/Asset Duration Gap...

Meyers, Alison J.

2012-06-07

313

Cognitive Assessment in Long-Duration Space Flight  

NASA Technical Reports Server (NTRS)

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.

Kane, Robert; Seaton, Kimberly; Sipes, Walter

2011-01-01

314

Building a Shared Definitional Model of Long Duration Human Spaceflight  

NASA Technical Reports Server (NTRS)

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

Arias, Diana; Orr, Martin; Whitmire, Alexandra; Leveton, Lauren; Sandoval, Luis

2012-01-01

315

Believing Is Seeing: Fixation Duration Predicts Implicit Negative Attitudes  

PubMed Central

A prototypical finding of social cognition is that social experiences influence later performance even though those experiences are not introspectively available. Building on social cognition research on implicit attitudes, we evaluate whether ethnic category/attribute pairs influence eye movements during the Implicit Association Test (IAT, Greenwald, McGhee, & Schwartz 1998). Results show that fixation duration predicted implicit attitudes such that when the category/attribute pairs disconfirmed one's implicit negative attitude fixation duration toward that pair increased. The present research provides evidence that eye movements and implicit processes inherent in the IAT are more broadly connected than previously thought. PMID:25133639

2014-01-01

316

Crew productivity issues in long-duration space flight  

NASA Technical Reports Server (NTRS)

Considerable evidence suggests the importance of teamwork, coordination, and conflict resolution to the performance and survival of isolated, confined groups in high-technology environments. With the advent of long-duration space flight, group-related issues of crew functioning will take on added significance. This paper discusses the influence of crew roles, status, leadership, and norms on the performance of small, confined groups, and offers guidelines and suggestions regarding organizational design, crew selection, training, and team building for crew productivity and social well-being in long-duration spaceflight.

Nicholas, John M.; Foushee, H. Clayton; Ulschak, Francis L.

1988-01-01

317

Right Hemispheric Contributions to Fine Auditory Temporal Discriminations: High-Density Electrical Mapping of the Duration Mismatch Negativity (MMN)  

PubMed Central

That language processing is primarily a function of the left hemisphere has led to the supposition that auditory temporal discrimination is particularly well-tuned in the left hemisphere, since speech discrimination is thought to rely heavily on the registration of temporal transitions. However, physiological data have not consistently supported this view. Rather, functional imaging studies often show equally strong, if not stronger, contributions from the right hemisphere during temporal processing tasks, suggesting a more complex underlying neural substrate. The mismatch negativity (MMN) component of the human auditory evoked-potential provides a sensitive metric of duration processing in human auditory cortex and lateralization of MMN can be readily assayed when sufficiently dense electrode arrays are employed. Here, the sensitivity of the left and right auditory cortex for temporal processing was measured by recording the MMN to small duration deviants presented to either the left or right ear. We found that duration deviants differing by just 15% (i.e. rare 115?ms tones presented in a stream of 100?ms tones) elicited a significant MMN for tones presented to the left ear (biasing the right hemisphere). However, deviants presented to the right ear elicited no detectable MMN for this separation. Further, participants detected significantly more duration deviants and committed fewer false alarms for tones presented to the left ear during a subsequent psychophysical testing session. In contrast to the prevalent model, these results point to equivalent if not greater right hemisphere contributions to temporal processing of small duration changes. PMID:19430594

De Sanctis, Pierfilippo; Molholm, Sophie; Shpaner, Marina; Ritter, Walter; Foxe, John J.

2009-01-01

318

Right Hemispheric Contributions to Fine Auditory Temporal Discriminations: High-Density Electrical Mapping of the Duration Mismatch Negativity (MMN).  

PubMed

That language processing is primarily a function of the left hemisphere has led to the supposition that auditory temporal discrimination is particularly well-tuned in the left hemisphere, since speech discrimination is thought to rely heavily on the registration of temporal transitions. However, physiological data have not consistently supported this view. Rather, functional imaging studies often show equally strong, if not stronger, contributions from the right hemisphere during temporal processing tasks, suggesting a more complex underlying neural substrate. The mismatch negativity (MMN) component of the human auditory evoked-potential provides a sensitive metric of duration processing in human auditory cortex and lateralization of MMN can be readily assayed when sufficiently dense electrode arrays are employed. Here, the sensitivity of the left and right auditory cortex for temporal processing was measured by recording the MMN to small duration deviants presented to either the left or right ear. We found that duration deviants differing by just 15% (i.e. rare 115 ms tones presented in a stream of 100 ms tones) elicited a significant MMN for tones presented to the left ear (biasing the right hemisphere). However, deviants presented to the right ear elicited no detectable MMN for this separation. Further, participants detected significantly more duration deviants and committed fewer false alarms for tones presented to the left ear during a subsequent psychophysical testing session. In contrast to the prevalent model, these results point to equivalent if not greater right hemisphere contributions to temporal processing of small duration changes. PMID:19430594

De Sanctis, Pierfilippo; Molholm, Sophie; Shpaner, Marina; Ritter, Walter; Foxe, John J

2009-01-01

319

42 CFR 418.21 - Duration of hospice care coverage-Election periods.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 false Duration of hospice care coverage-Election periods. 418...CONTINUED) MEDICARE PROGRAM (CONTINUED) HOSPICE CARE Eligibility, Election and Duration of Benefits § 418.21 Duration of hospice care coverage—Election...

2012-10-01

320

42 CFR 418.21 - Duration of hospice care coverage-Election periods.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 false Duration of hospice care coverage-Election periods. 418...SERVICES (CONTINUED) MEDICARE PROGRAM HOSPICE CARE Eligibility, Election and Duration of Benefits § 418.21 Duration of hospice care coverage—Election...

2011-10-01

321

42 CFR 418.21 - Duration of hospice care coverage-Election periods.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 false Duration of hospice care coverage-Election periods. 418...CONTINUED) MEDICARE PROGRAM (CONTINUED) HOSPICE CARE Eligibility, Election and Duration of Benefits § 418.21 Duration of hospice care coverage—Election...

2013-10-01

322

42 CFR 418.21 - Duration of hospice care coverage-Election periods.  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 false Duration of hospice care coverage-Election periods. 418...SERVICES (CONTINUED) MEDICARE PROGRAM HOSPICE CARE Eligibility, Election and Duration of Benefits § 418.21 Duration of hospice care coverage—Election...

2010-10-01

323

38 CFR 21.8070 - Basic duration of a vocational training program.  

Code of Federal Regulations, 2012 CFR

...false Basic duration of a vocational training program. 21.8070 Section 21...REHABILITATION AND EDUCATION Vocational Training and Rehabilitation for Certain Children...Birth Defects Duration of Vocational Training § 21.8070 Basic duration of a...

2012-07-01

324

38 CFR 21.6070 - Basic duration of a vocational training program.  

Code of Federal Regulations, 2013 CFR

...false Basic duration of a vocational training program. 21.6070 Section 21.6070...EDUCATION Temporary Program of Vocational Training for Certain New Pension Recipients Duration of Training § 21.6070 Basic duration of a...

2013-07-01

325

38 CFR 21.6070 - Basic duration of a vocational training program.  

Code of Federal Regulations, 2012 CFR

...false Basic duration of a vocational training program. 21.6070 Section 21.6070...EDUCATION Temporary Program of Vocational Training for Certain New Pension Recipients Duration of Training § 21.6070 Basic duration of a...

2012-07-01

326

38 CFR 21.8070 - Basic duration of a vocational training program.  

Code of Federal Regulations, 2013 CFR

...false Basic duration of a vocational training program. 21.8070 Section 21...REHABILITATION AND EDUCATION Vocational Training and Rehabilitation for Certain Children...Birth Defects Duration of Vocational Training § 21.8070 Basic duration of a...

2013-07-01

327

38 CFR 21.8070 - Basic duration of a vocational training program.  

Code of Federal Regulations, 2010 CFR

...false Basic duration of a vocational training program. 21.8070 Section 21...REHABILITATION AND EDUCATION Vocational Training and Rehabilitation for Certain Children...Birth Defects Duration of Vocational Training § 21.8070 Basic duration of a...

2010-07-01

328

38 CFR 21.6070 - Basic duration of a vocational training program.  

Code of Federal Regulations, 2011 CFR

...false Basic duration of a vocational training program. 21.6070 Section 21.6070...EDUCATION Temporary Program of Vocational Training for Certain New Pension Recipients Duration of Training § 21.6070 Basic duration of a...

2011-07-01

329

38 CFR 21.6070 - Basic duration of a vocational training program.  

Code of Federal Regulations, 2010 CFR

...false Basic duration of a vocational training program. 21.6070 Section 21.6070...EDUCATION Temporary Program of Vocational Training for Certain New Pension Recipients Duration of Training § 21.6070 Basic duration of a...

2010-07-01

330

The value of the 12-lead ECG for evaluation and optimization of cardiac resynchronization therapy in daily clinical practice.  

PubMed

Based on existing literature and some new data we propose a simple three-step strategy using the standard 12-lead ECG for patient selection and optimal delivery of cardiac resynchronization therapy (CRT). (1) Complete LBBB with regard to the indication for CRT can probably best be identified by a QRS duration of ? 130 ms for women and ? 120 ms for men with the presence of mid-QRS notch-/slurring in ? 2 contiguous leads of V1, V2, V5, V6, I and aVL. (2) Left ventricular (LV) free wall pacing should result in a positive QRS complex in lead V1, with estimation of the exact LV lead position in the circumferential and apico-basal direction using lead aVF and the precordial leads, respectively. Wide and fractionated LV-paced QRS complexes may indicate pacing in scar tissue. (3) Atrioventricular and interventricular stimulation intervals may be optimized by adjusting them until precordial leads show fusion patterns between left and right ventricular activation wavefronts in the QRS complex. PMID:24444866

van Deursen, Caroline J M; Blaauw, Yuri; Witjens, Maryvonne I; Debie, Luuk; Wecke, Liliane; Crijns, Harry J G M; Prinzen, Frits W; Vernooy, Kevin

2014-01-01

331

Mediating Civil War Settlements and the Duration of Peace  

Microsoft Academic Search

In this article, we examine the impact of international mediation attempts during civil war on the duration of peace once the war has ended. We include several aspects of the mediation attempt in our theoretical framework and our empirical tests, but we also control for other characteristics of the conflict and the country. While studies often find that decisive victories

Mehmet Gurses; Nicolas Rost; Patrick McLeod

2008-01-01

332

EXPECTATIONS OF PSYCHOTHERAPY DURATION: HOW LONG SHOULD PSYCHOTHERAPY LAST?  

Microsoft Academic Search

The authors surveyed 1,000 members of APA Division 29 (Psychotherapy) regarding their expectations of the number of psychotherapy sessions needed to successfully treat persons with various psychological disorders. Based on a response rate of 28%, psychologists expected 30 to 40 sessions of individual psychotherapy to achieve clinically significant change. Differences in treatment duration expectancies were associated with client diagnosis and

Jenny L. Lowry; Michael J. Ross

1997-01-01

333

Physical Activity Duration, Intensity, and Arterial Stiffening in Postmenopausal Women  

Microsoft Academic Search

Background: Aerobic exercise training is associated with lower central arterial stiffness, but little information exists on the effects of physical activity intensity or duration on central arterial stiffness. Using a cross-sectional and interventional approach, we tested the hypothesis that both moderate and vigorous physical activity reduce central arterial stiffness in postmenopausal women.Methods: Carotid arterial stiffness (via ultrasound and applanation tonometry)

Jun Sugawara; Takeshi Otsuki; Takumi Tanabe; Koichiro Hayashi; Seiji Maeda; Mitsuo Matsuda

2006-01-01

334

Effect of Zanamivir on Duration and Resolution of Influenza Symptoms  

Microsoft Academic Search

Background: Zanamivir is a neuraminidase inhibitor, the first of a new class of drugs with potent, specific antiviral activity against influenza A and B. Administration by inhala- tion results in direct delivery to the respiratory tract, the principal site of viral replication. Objective: This study was undertaken to determine the effectiveness of zanamivir on duration and resolution of influenza symptoms.

Arnold S. Monte; Andrew B. Moult; Stephen J. Sharp

335

Effect of zanamivir on duration and resolution of influenza symptoms  

Microsoft Academic Search

Background: Zanamivir is a neuraminidase inhibitor, the first of a new class of drugs with potent, specific antiviral activity against influenza A and B. Administration by inhalation results in direct delivery to the respiratory tract, the principal site of viral replication.Objective: This study was undertaken to determine the effectiveness of zanamivir on duration and resolution of influenza symptoms.Methods: Using a

Arnold S. Monto; Andrew B. Moult; Stephen J. Sharp

2000-01-01

336

Fixed-Duration Therapy in Leprosy: Limitations and Opportunities  

PubMed Central

Leprosy has been considered a curable disease after the implementation of multidrug therapy (MDT), which has been proven to be safe and effective, by bringing about a significant change in the global and national scenario of leprosy by upgrading the control of leprosy to the next stage of eradication. Since its introduction, the MDT regimens for the treatment of leprosy have undergone several changes especially with regard to the duration of treatment. The advantages of shortened duration of treatment need to be balanced against the risk of relapse and a lot of controversies exist pertaining to this aspect. The fixed-duration (FD) therapy is not popular among academicians and private practitioners who prefer precise diagnosis and treatment with superior MDT regimens and for a longer duration. On the contrary, from a public health-care point of view, precise diagnosis and a longer treatment schedule are not cost effective and not feasible to be implemented in elimination programs. Hence, a fine balance needs to be maintained between achieving a cure for the patient and protecting the society at risk, and this review discusses the various limitations and opportunities of FD therapy with a note on the newer MDT regimens. PMID:23716796

Malathi, Munisamy; Thappa, Devinder Mohan

2013-01-01

337

Fixed-duration therapy in leprosy: limitations and opportunities.  

PubMed

Leprosy has been considered a curable disease after the implementation of multidrug therapy (MDT), which has been proven to be safe and effective, by bringing about a significant change in the global and national scenario of leprosy by upgrading the control of leprosy to the next stage of eradication. Since its introduction, the MDT regimens for the treatment of leprosy have undergone several changes especially with regard to the duration of treatment. The advantages of shortened duration of treatment need to be balanced against the risk of relapse and a lot of controversies exist pertaining to this aspect. The fixed-duration (FD) therapy is not popular among academicians and private practitioners who prefer precise diagnosis and treatment with superior MDT regimens and for a longer duration. On the contrary, from a public health-care point of view, precise diagnosis and a longer treatment schedule are not cost effective and not feasible to be implemented in elimination programs. Hence, a fine balance needs to be maintained between achieving a cure for the patient and protecting the society at risk, and this review discusses the various limitations and opportunities of FD therapy with a note on the newer MDT regimens. PMID:23716796

Malathi, Munisamy; Thappa, Devinder Mohan

2013-03-01

338

Long Duration Space Missions: Human Subsystem Risks and Requirements  

NASA Technical Reports Server (NTRS)

This viewgraph presentation reviews the human health and performance risks associated with long duration space flight beyond low earth orbit. The contents include: 1) Human Research Program; 2) Human Subsystem Risks; 3) Human Exploration Framework Team (HEFT) Architecture Elements; 4) Potentially Unacceptable Risks -1; 5) Potentially Unacceptable Risks-2; and 6) Major Mission Drivers of Risk.

Kundrot, Criag E.

2011-01-01

339

Correcting Memory Improves Accuracy of Predicted Task Duration  

ERIC Educational Resources Information Center

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…

Roy, Michael M.; Mitten, Scott T.; Christenfeld, Nicholas J. S.

2008-01-01

340

Attention, Exposure Duration, and Gaze Shifting in Naming Performance  

ERIC Educational Resources Information Center

Two experiments are reported in which the role of attribute exposure duration in naming performance was examined by tracking eye movements. Participants were presented with color-word Stroop stimuli and left- or right-pointing arrows on different sides of a computer screen. They named the color attribute and shifted their gaze to the arrow to…

Roelofs, Ardi

2011-01-01

341

A frequency and duration method for generating system reliability evaluation  

Microsoft Academic Search

The paper presents a method for computing exactly the frequency and duration of load loss events as measures of generating system reliability. The method utilizes an exact state capacity model together with a cumulative state load model which requires no idealization. Efficient computer algorithms for building the exact state capacity model and computing the system reliability indices are presented.

A. K. Ayoub; A. D. Patton

1976-01-01

342

Larval habitat duration and size at metamorphosis in frogs  

Microsoft Academic Search

The relationship between size at metamorphosis and adult size was studied in 12 closely-related species of frog from Malawi (Central Africa). These species of frogs breed in water of different durations, and occupy different habitats as adults. We could demonstrate no correlation between size at metamorphosis and size of adults when frogs were divided into groups on the basis of

Jeremy W. Patterson; Athol J. McLachlan

1989-01-01

343

Microwave Preflare Enhancement and Depletion in Long Duration Events  

NASA Astrophysics Data System (ADS)

Combination of weak microwave enhancement and depletion has been found in the pre-flare phases of three long-duration solar flares observed with the Nobeyama radioheliograph (NRH) at 17 GHz. This starts about two hours prior to subsequent main flare. Emission measure and temperature indicate that the enhancement and the depletion are caused by a, relatively cool plasma motion

Fujiki, K.; Nakajima, H.

344

The Hardness-Duration Diagram of Gamma-Ray Bursts  

Microsoft Academic Search

The hardness-duration diagram for gamma-ray bursts still contains undiscovered important information about the intrinsic properties of these phenomena. We analyze these diagrams for the PHEBUS and BATSE experiments. First, we show that the BATSE diagram is very similar to that for PHEBUS when we restrict the BATSE data set to events observable by PHEBUS. In this case, both diagrams present

J. P. Dezalay; J. P. Lestrade; C. Barat; R. Talon; R. Sunyaev; O. Terekhov; A. Kuznetsov

1996-01-01

345

Temporal Context in Concurrent Chains: I. Terminal-Link Duration  

ERIC Educational Resources Information Center

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 components…

Grace, Randolph C.

2004-01-01

346

Subjective shortening: A model of pigeons' memory for event duration  

Microsoft Academic Search

Investigated memory for event duration using a delayed matching-to-sample procedure in 4 experiments with 10 Silver King pigeons. When a retention interval of variable length intervened between sample and comparison stimuli, Ss responded as though long samples had been short after retention intervals of 10 sec or more. This \\

Marcia L. Spetch; Donald M. Wilkie

1983-01-01

347

Adaptive variability in the duration of critical windows of plasticity  

PubMed Central

Developmental plasticity underlies widespread associations between early-life exposures and many components of adult phenotype, including the risk of chronic diseases. Humans take almost two decades to reach reproductive maturity, and yet the ‘critical windows’ of physiological sensitivity that confer developmental plasticity tend to close during fetal life or infancy. While several explanations for lengthy human maturation have been offered, the brevity of physiological plasticity has received less attention. I argue that offspring plasticity is only viable within the niche of maternal care, and that as this protection is withdrawn, the offspring is obliged to canalize many developmental traits in order to minimize environmental disruptions. The schedule of maternal care may therefore shape the duration of critical windows, and since the duration of this care is subject to parent–offspring conflict, the resolution of this conflict may shape the duration of critical windows. This perspective may help understand (i) why windows close at different times for different traits, and (ii) why the duration of critical windows may vary across human populations. The issue is explored in relation to population differences in the association between infant weight gain and later body composition. The occupation of more stable environments by western populations may have favoured earlier closure of the critical window during which growth in lean mass is sensitive to nutritional intake. This may paradoxically have elevated the risk of obesity following rapid infant weight gain in such populations. PMID:25095791

Wells, Jonathan C. K.

2014-01-01

348

Articulatory Duration in Single-Word Speech Production  

Microsoft Academic Search

Three different speech production paradigms assessed C. T. Kello, D. C. Plaut, and B. MacWhinney's (2000) claim that the characteristics of speech production flexibly vary between staged and cascaded modes depending on task demand. All experiments measured response latencies and durations of single words without and with a response deadline. Experiment 1 used a picture?word interference task; Experiment 2 blocked

Markus F. Damian

2003-01-01

349

The effects of odor and body posture on perceived duration  

PubMed Central

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

Schreuder, Eliane; Hoeksma, Marco R.; Smeets, Monique A. M.; Semin, Gun R.

2013-01-01

350

Duration of spermatogenesis in the bullfrog (Lithobates catesbeianus).  

PubMed

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

Segatelli, T M; Batlouni, S R; França, L R

2009-10-15

351

CAVE CRICKET EXIT COUNTS: ENVIRONMENTAL INFLUENCES AND DURATION OF SURVEYS  

E-print Network

CAVE CRICKET EXIT COUNTS: ENVIRONMENTAL INFLUENCES AND DURATION OF SURVEYS FLOYD W. WECKERLY1 1.edu Abstract: Cave cricket abundance is used as an indicator of integrity of cave ecosystems. One means of monitoring cave cricket abundance is counting crickets as they emerge from cave entrances for two hours after

Aspbury, Andrea S. - Department of Biology, Texas State University

352

Breastfeeding behavior among adolescents: Initiation, duration, and exclusivity  

PubMed Central

Purpose Despite a substantial amount of evidence on breastfeeding among non-adolescent mothers, research and strategies uniquely designed to target adolescent mothers are critical as their rates of breastfeeding are disproportionately low and their transition to parenthood is often unlike that of older mothers. Literature to date, however, offers limited evidence for designing effective interventions. Therefore, we aim to fill this gap in the literature by examining breastfeeding behaviors among a cohort of female adolescents as they transition to parenthood. Methods Data are derived from a longitudinal cohort of pregnant adolescent females (ages 14-21) and their male partners followed from pregnancy through 6 months postpartum. Means and frequencies were used to describe breastfeeding experiences, breastfeeding behaviors, and sociodemographic characteristics. Multivariate logistic regression and Cox proportional hazards models were used to identify factors independently associated with breastfeeding initiation, exclusive breastfeeding, and breastfeeding duration. Results Approximately 71% initiated breastfeeding. Intending to breastfeed, having had complications in labor and delivery, and lower social support were associated with greater odds of breastfeeding initiation. Of the adolescent mothers who initiated breastfeeding, 84% had stopped by 6 months postpartum and among those, average breastfeeding duration was 5 weeks. Participants who exclusively breastfed had longer breastfeeding duration, and participants who had experienced intimate partner violence had shorter breastfeeding duration. Obese women and women who had more difficulty breastfeeding had lower odds of exclusive breastfeeding. Conclusions Enhanced clinical support and the promotion of exclusive breastfeeding should be considered when designing interventions to improve breastfeeding rates among adolescent mothers. PMID:23725911

Sipsma, Heather L.; Magriples, Urania; Divney, Anna; Gordon, Derrick; Gabzdyl, Elizabeth; Kershaw, Trace

2013-01-01

353

DIABETES MEDICATIONS: INSULIN INSULIN TYPE & DURATION OF ACTION NAMES ACTION  

E-print Network

DIABETES MEDICATIONS: INSULIN INSULIN TYPE & DURATION OF ACTION NAMES ACTION Rapid-acting insulin to be taken with food. Use as prescribed by your provider. -Always carry a source of glucose/sugar on you in order to prevent or treat a dangerous low blood glucose reaction. Ask your diabetes educator or provider

Oliver, Douglas L.

354

Transformational leadership and outcomes: role of relationship duration  

Microsoft Academic Search

Purpose – To show that relationship duration enhances the effect of transformational leadership on follower's terminal value system congruence and identification (cognitive outcomes), but not on attachment and affective commitment (affective outcomes). Design\\/methodology\\/approach – Data for this study were collected from the principal and 144 teachers of a prominent high school in western India. The principal and the teachers answered

Venkat R. Krishnan

2005-01-01

355

CRISP: A Computational Model of Fixation Durations in Scene Viewing  

ERIC Educational Resources Information Center

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.…

Nuthmann, Antje; Smith, Tim J.; Engbert, Ralf; Henderson, John M.

2010-01-01

356

RESEARCH PAPER Residency Duration and Shelter Quality Influence Vibratory  

E-print Network

) doi: 10.1111/eth.12210 Keywords: motivation, territory, caterpillar, value assessment, silk, vibration to assess how residency duration and shelter quality independently affected territorial displays during such as negotiating Ethology 120 (2014) 1�11 � 2014 Blackwell Verlag GmbH 1 Ethology #12;with neighbours or builds

Yack, Jayne E.

357

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.

1972-01-01

358

How Do Changes in Speed Affect the Perception of Duration?  

ERIC Educational Resources Information Center

Six experiments investigated how changes in stimulus speed influence subjective duration. Participants saw rotating or translating shapes in three conditions: constant speed, accelerating motion, and decelerating motion. The distance moved and average speed were the same in all three conditions. In temporal judgment tasks, the constant-speed…

Matthews, William J.

2011-01-01

359

Spectral loudness summation as a function of duration  

NASA Astrophysics Data System (ADS)

Loudness was measured as a function of signal bandwidth for 10-, 100-, and 1000-ms-long signals. The test and reference signals were bandpass-filtered noise spectrally centered at 2 kHz. The bandwidth of the test signal was varied from 200 to 6400 Hz. The reference signal had a bandwidth of 3200 Hz. The reference levels were 45, 55, and 65 dB SPL. The level to produce equal loudness was measured with an adaptive, two-interval, two-alternative forced-choice procedure. A loudness matching procedure was used, where the tracks for all signal pairs to be compared were interleaved. Mean results for nine normal-hearing subjects showed that the magnitude of spectral loudness summation depends on signal duration. For all reference levels, a 6- to 8-dB larger level difference between equally loud signals with the smallest (?f=200 Hz) and largest (?f=6400 Hz) bandwidth is found for 10-ms-long signals than for the 1000-ms-long signals. The duration effect slightly decreases with increasing reference loudness. As a consequence, loudness models should include a duration-dependent compression stage. Alternatively, if a fixed loudness ratio between signals of different duration is assumed, this loudness ratio should depend on the signal spectrum.

Verhey, Jesko L.; Kollmeier, Birger

2002-03-01

360

Rats' Memory for Time and Relational Responding in the Duration-Comparison Procedure  

ERIC Educational Resources Information Center

Rats were trained in a duration-comparison task to press one lever if the comparison duration ("c") was 1.2-s shorter than a standard duration ("s"), and another lever if c was 1.2-s longer than s. The interval between s and c duration was 1 s. The 10 duration pairs used during training controlled for the absolute duration of "c" and the total…

Santi, Angelo; Hoover, Claire; Simmons, Sabrina

2011-01-01

361

Trip recovery strategies following perturbations of variable duration.  

PubMed

Appropriately responding to mechanical perturbations during gait is critical to maintain balance and avoid falls. Tripping perturbation onset during swing phase is strongly related to the use of different recovery strategies; however, it is insufficient to fully explain how strategies are chosen. The dynamic interactions between the foot and the obstacle may further explain observed recovery strategies but the relationship between such contextual elements and strategy selection has not been explored. In this study, we investigated whether perturbation onset, duration and side could explain strategy selection for all of swing phase. We hypothesized that perturbations of longer duration would elicit lowering and delayed-lowering strategies earlier in swing phase than shorter perturbations. We developed a custom device to trip subjects multiple times while they walked on a treadmill. Seven young, healthy subjects were tripped on the left or right side at 10% to 80% of swing phase for 150 ms, 250 ms or 350 ms. Strategies were characterized by foot motion post-perturbation and identified by an automated algorithm. A multinomial logistic model was used to investigate the effect of perturbation onset, side, and the interaction between duration and onset on recovery strategy selection. Side perturbed did not affect strategy selection. Perturbation duration interacted with onset, limiting the use of elevating strategies to earlier in swing phase with longer perturbations. The choice between delayed-lowering and lowering strategies was not affected by perturbation duration. Although these variables did not fully explain strategy selection, they improved the prediction of strategy used in response to tripping perturbations throughout swing phase. PMID:24894024

Shirota, Camila; Simon, Ann M; Kuiken, Todd A

2014-08-22

362

Shortened Sleep Duration does not Predict Obesity in Adolescents  

PubMed Central

Obesity continues to be a major public health issue. In adolescents, there are limited studies on the relationship between obesity and sleep duration. We hypothesied that average sleep duration of less than 6 hours in adolescents was associated with obesity. Data was from the National Longitudinal Study of Adolescent Health (ADD Health); survey of 90,000 youths, ages 12 – 18 years; surveyed in several waves. The sample population for our study was 13,568. Weighted multiple logistic regression was used to identify relationship between obesity at Wave II and sleep duration, having adjusted for skipping breakfast ? 2/week; race, gender, parental income, TV ? 2hrs/day, depression, and obesity at Wave I. At Wave I, mean age 15.96±0.11 yrs; mean sleep hours 7.91±0.04. 10.6% and 11.2% of adolescents were obese at Waves I and II, respectively. Adjusted analyses suggest that effect of shortened sleep duration in Wave I was not significantly predictive of obesity in Wave II (p<0.218).Longitudinally, depression and TV ? 2hrs/day at Wave I was associated with higher risk of obesity at Wave II in adjusted analyses. Depressed adolescents were almost twice as likely to be obese (OR=1.84, 95% CI=1.25–2.72); adolescents who watched TV ? 2hrs/day were 37% more likely to be obese (OR=1.37, 95% CI=1.09–1.72).Environmental factors including TV ? 2hrs/day and depression were significantly associated with obesity; shortened sleep duration was not. Future longitudinal studies in adolescents are needed to determine whether timing of television watching directly influences sleep patterns, and ultimately obesity. PMID:20545836

Calamaro, Christina J.; Park, Sunhee; Mason, Thornton B. A.; Marcus, Carole L.; Weaver, Terri E.; Pack, Allan; Ratcliffe, Sarah J.

2010-01-01

363

40 CFR 18.9 - Duration of Environmental Protection Research Fellowships.  

Code of Federal Regulations, 2010 CFR

... Duration of Environmental Protection Research Fellowships. 18.9 ...AGENCY GENERAL ENVIRONMENTAL PROTECTION RESEARCH FELLOWSHIPS AND SPECIAL RESEARCH... Duration of Environmental Protection Research Fellowships. Initial...

2010-07-01

364

Reduced heart rate variability during sleep in long-duration spaceflight.  

PubMed

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

Xu, D; Shoemaker, J K; Blaber, A P; Arbeille, P; Fraser, K; Hughson, R L

2013-07-15

365

A generalized seasonal model for flow duration curve  

NASA Astrophysics Data System (ADS)

In this study a new method is developed to determine a flow duration curve (FDC) for a process in which stream flow is defined as a product of two variables, representing the periodic and the stochastic components, respectively. The cumulative frequency distribution is obtained via integration procedures and also given as an algorithm for discrete variables. Hence the exceedance probability for any given flow value can be calculated. The method is applied to daily flow data from many sites and it is found that the FDCs based on this method compare well with the observed FDC. Furthermore the FDCs developed in this method compare well with other methods in the recent literature. It was found that non-dimensional flow duration curves in Turkey can be characterized by three, or sometimes just two, parameters. Values of these parameters have been estimated at many sites enabling a FDC to be constructed at neighbouring sites for which only the drainage basin area is known.

Cigizoglu, H. Kerem; Bayazit, Mehmetcik

2000-04-01

366

Effects of september 11th terrorism stress on estimated duration.  

PubMed

Previous research has suggested that the duration of stressful video material is estimated to be longer than one containing less stressful material. The current study sought to examine what effects viewing news coverage of the September 11th 2001 terrorist attacks might have on estimated duration of exposure. 16 participants were recruited from Saint Joseph's College of Maine psychology courses and viewed two 3-min. video clips. One clip contained coverage of the 9-11 terrorist attacks; the other, a nonstressful control, was taken from a familiar segment of The Wizard of Oz. Participants estimated the length of the clip and rated stress experienced while viewing the clip. Analysis showed the September 11th footage was rated as more stressful and was estimated as longer than the control clip. PMID:17688136

Anderson, Matthew J; Reis-Costa, Kathleen; Misanin, James R

2007-06-01

367

Electronic Repair Concepts for Long-Duration Spaceflight  

NASA Technical Reports Server (NTRS)

Constraints on the mass and volume that can be allocated for electronics spares and repair equipment on long-duration space missions mean that NASA must look at repair strategies beyond the traditional approach, which has been to replace faulty subsystems in a modular form, termed Orbital Replacement Units or Line Replacement Units. Other possible strategies include component and board-level replacement, modular designs that allow reprogramming of less-critical systems to take the place of more critical failed systems, and a blended approach which uses elements of each of these approaches, along with a limited number of Line Replacement Units. This paper presents some of the constraints and considerations that affect the decision on how to approach electronics repair for long duration space missions, and discusses the benefits and limitations of each of the previously mentioned strategies.

Easton, John; Pettegrew, Richard D.; Struk, Peter M.

2007-01-01

368

Sleep duration and cardiovascular responses to stress in undergraduate men.  

PubMed

Short sleep has been related to incident cardiovascular disease, but physiological mechanisms accounting for this relationship are largely unknown. This study examines sleep duration and cardiovascular stress responses in 79 healthy, young men. Sleep duration was assessed by wrist actigraphy for seven nights. Participants then completed a series of laboratory stress tasks while heart rate and blood pressure were monitored. Shorter total sleep time was related to a greater reduction in high-frequency heart rate variability during stress tasks, and to prolonged elevations in heart rate and diastolic pressure following tasks. Associations were independent of age, race, body mass index, caffeine intake, and smoking status. In sum, healthy young men with shorter actigraphy-assessed sleep exhibit less cardiac vagal activity, and poorer heart rate and diastolic blood pressure recovery, upon encountering stressful stimuli, than those with longer sleep. PMID:24016263

Mezick, Elizabeth J; Matthews, Karen A; Hall, Martica H; Richard Jennings, J; Kamarck, Thomas W

2014-01-01

369

Space mechanisms needs for future NASA long duration space missions  

NASA Technical Reports Server (NTRS)

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.

Fusaro, Robert L.

1991-01-01

370

Extended duration orbiter study: CO2 removal and water recovery  

NASA Technical Reports Server (NTRS)

Two electrochemical depolarized carbon dioxide concentrator subsystems were evaluated against baseline lithium hydroxide for (1) the baseline orbiter when expanded to accommodate a crew of seven (mission option one), (2) an extended duration orbiter with a power extension package to reduce fuel cell expendables (mission option two), and (3) an extended duration orbiter with a full capability power module to eliminate fuel cell expendables (mission option three). The electrochemical depolarized carbon dioxide concentrator was also compared to the solid amine regenerable carbon dioxide removal concept. Water recovery is not required for Mission Option One since sufficient water is generated by the fuel cells. The vapor compression distillation subsystem was evaluated for mission option two and three only. Weight savings attainable using the vapor compression distillation subsystem for water recovery versus on-board water storage were determined. Combined carbon dioxide removal and water recovery was evaluated to determine the effect on regenerable carbon dioxide removal subsystem selection.

Marshall, R. D.; Ellis, G. S.; Schubert, F. H.; Wynveen, R. A.

1979-01-01

371

Habitability and Performance Issues for Long Duration Space Flights  

NASA Technical Reports Server (NTRS)

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.

Whitmore, Mihriban; McQuilkin, Meredith L.; Woolford, Barbara J.

1997-01-01

372

Extended Duration Orbiter (EDO) Improved Waste Collection System (IWCS)  

NASA Technical Reports Server (NTRS)

This overall front view shows the Extended Duration Orbiter (EDO) Waste Collection System (WCS) scheduled to fly aboard NASA's Endeavour, Orbiter Vehicle (OV) 105, for the STS-54 mission. Detailed Test Objective 662, Extended duration orbiter WCS evaluation, will verify the design of the new EDO WCS under microgravity conditions for a prolonged period. OV-105 has been modified with additional structures in the waste management compartment (WMC) and additional avionics to support/restrain the EDO WCS. Among the advantages the new IWCS is hoped to have over the currect WCS are greater dependability, better hygiene, virtually unlimited capacity, and more efficient preparation between shuttle missions. Unlike the previous WCS, the improved version will not have to be removed from the spacecraft to be readied for the next flight. The WCS was documented in JSC's Crew Systems Laboratory Bldg 7.

1992-01-01

373

Extended Duration Orbiter (EDO) Improved Waste Collection System (IWCS)  

NASA Technical Reports Server (NTRS)

This high angle overall view shows the top side components of the Extended Duration Orbiter (EDO) Waste Collection System (WCS) scheduled to fly aboard NASA's Endeavour, Orbiter Vehicle (OV) 105, for the STS-54 mission. Detailed Test Objective 662, Extended duration orbiter WCS evaluation, will verify the design of the new EDO WCS under microgravity conditions for a prolonged period. OV-105 has been modified with additional structures in the waste management compartment (WMC) and additional avionics to support/restrain the EDO WCS. Among the advantages the new IWCS is hoped to have over the currect WCS are greater dependability, better hygiene, virtually unlimited capacity, and more efficient preparation between shuttle missions. Unlike the previous WCS, the improved version will not have to be removed from the spacecraft to be readied for the next flight. The WCS was documented in JSC's Crew Systems Laboratory Bldg 7.

1992-01-01

374

Long Duration Hot Hydrogen Exposure of Nuclear Thermal Rocket Materials  

NASA Technical Reports Server (NTRS)

An arc-heater driven hyper-thermal convective environments simulator was recently developed and commissioned for long duration hot hydrogen exposure of nuclear thermal rocket materials. This newly established non-nuclear testing capability uses a high-power, multi-gas, wall-stabilized constricted arc-heater to .produce high-temperature pressurized hydrogen flows representative of nuclear reactor core environments, excepting radiation effects, and is intended to serve as a low cost test facility for the purpose of investigating and characterizing candidate fuel/structural materials and improving associated processing/fabrication techniques. Design and engineering development efforts are fully summarized, and facility operating characteristics are reported as determined from a series of baseline performance mapping runs and long duration capability demonstration tests.

Litchford, Ron J.; Foote, John P.; Hickman, Robert; Dobson, Chris; Clifton, Scooter

2007-01-01

375

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.

1997-01-01

376

Racial Disparities in Short Sleep Duration by Occupation and Industry  

PubMed Central

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

Jackson, Chandra L.; Redline, Susan; Kawachi, Ichiro; Williams, Michelle A.; Hu, Frank B.

2013-01-01

377

Lithium elimination half-life and duration of therapy  

Microsoft Academic Search

The elimination half-life (t½E) of lithium carbonate in red blood cells, plasma, and urine was measured in 30 patients hospitalized for primary affective disorder. Duration of Li treatment at time of sampling was found to have a direct effect on lengthening time course. Patients on their initial course of Li had the lowest t½s: 1.12 (urine), 1.28 (plasma), and 1.22

Paul J Goodnick; Ronald R Fieve; Herbert L Meltzer; David L Dunner

1981-01-01

378

Observations of short-duration gamma-ray bursts  

NASA Astrophysics Data System (ADS)

Gamma-ray bursts (GRB) are the most powerful cosmological catastrophes in the Universe, with energy releases of 1048 - 1053 erg within a few tens of seconds. It is widely believed that progenitors of the short-duration class of GRB can be merging relativistic binary systems such as a neutron star (NS) and a black hole (BH) or NS-NS. We review the physics of GRBs, their phenomenological properties and observational evidence of GRBs, emphasizing optical observations of GRBs from Mongolia.

Pozanenko, Alexei; Volnova, Alina; Tungalag, Namkhai; Elenin, Leonid; Molotov, Igor; Voropaev, Victor; Schmalz, Sergey

2014-09-01

379

Offense–Defense Balance, War Duration, and the Security Dilemma  

Microsoft Academic Search

The systemic offense–defense theory argues that the security dilemma and the risk of war become doubly severe in offense-dominant eras in the state system. However, the theory assumes in support of its main argument that wars are shorter when offense has the advantage. This article empirically tests the expected connection between the systemic offense–defense balance and war duration. A statistical

Marco Nilsson

2012-01-01

380

Plasma Cytokine Levels During Long-Duration Spaceflight  

NASA Technical Reports Server (NTRS)

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.

Crucian, Brian E.; Zwart, Sara R.; Quiriarte, Heather A.; Smith, Scott M.; Sams, Clarence F.

2011-01-01

381

Shortening of Cardiac Action Potential Duration Near an Insulating Boundary  

PubMed Central

It is known, from both experiments and simulations, that cardiac action potentials are shortened near a nonconducting boundary. In the present paper, this effect is studied in a simple, two-current ionic model, with propagation restricted to a one-dimensional fiber. An asymptotic approximation for the dependence of action potential duration on distance to the boundary is derived. This estimate agrees well with simulations. PMID:18343886

Cain, John W.; Schaeffer, David G.

2008-01-01

382

Lipopolysaccharide prolongs action potential duration in HL-1 mouse cardiomyocytes.  

PubMed

Sepsis has deleterious effects on cardiac function including reduced contractility. We have shown previously that lipopolysaccharides (LPS) directly affect HL-1 cardiac myocytes by inhibiting Ca(2+) regulation and by impairing pacemaker "funny" current, I(f). We now explore further cellular mechanisms whereby LPS inhibits excitability in HL-1 cells. LPS (1 ?g/ml) derived from Salmonella enteritidis decreased rate of firing of spontaneous action potentials in HL-1 cells, and it increased their pacemaker potential durations and decreased their rates of depolarization, all measured by whole cell current clamp. LPS also increased action potential durations and decreased their amplitude in cells paced at 1 Hz with 0.1 nA, and 20 min were necessary for maximal effect. LPS decreased the amplitude of a rapidly inactivating inward current attributed to Na(+) and of an outward current attributed to K(+); both were measured by whole cell voltage clamp. The K(+) currents displayed a resurgent outward tail current, which is characteristic of the rapid delayed-rectifier K(+) current, I(Kr). LPS accordingly reduced outward currents measured with pipette Cs(+) substituted for K(+) to isolate I(Kr). E-4031 (1 ?M) markedly inhibited I(Kr) in HL-1 cells and also increased action potential duration; however, the direct effects of E-4031 occurred minutes faster than the slow effects of LPS. We conclude that LPS increases action potential duration in HL-1 mouse cardiomyocytes by inhibition of I(Kr) and decreases their rate of firing by inhibition of I(Na.) This protracted time course points toward an intermediary metabolic event, which either decreases available mouse ether-a-go-go (mERG) and Na(+) channels or potentiates their inactivation. PMID:22895260

Wondergem, Robert; Graves, Bridget M; Li, Chuanfu; Williams, David L

2012-10-15

383

Short Sleep Duration and Weight Gain: A Systematic Review  

Microsoft Academic Search

Objective:The recent obesity epidemic has been accompanied by a parallel growth in chronic sleep deprivation. Physiologic studies suggest sleep deprivation may influence weight through effects on appetite, physical activity, and\\/or thermoregulation. This work reviews the literature regarding short sleep duration as an independent risk factor for obesity and weight gain.Methods and Procedures:A literature search was conducted for all articles published

Sanjay R. Patel; Frank B. Hu

2008-01-01

384

TDR Using Autocorrelation and Varying-Duration Pulses  

NASA Technical Reports Server (NTRS)

In an alternative to a prior technique of time-domain-reflectometry (TDR) in which very short excitation pulses are used, the pulses have very short rise and fall times and the pulse duration is varied continuously between a minimum and a maximum value. In both the present and prior techniques, the basic idea is to (1) measure the times between the generation of excitation pulses and the reception of reflections of the pulses as indications of the locations of one or more defects along a cable and (2) measure the amplitudes of the reflections as indication of the magnitudes of the defects. In general, an excitation pulse has a duration T. Each leading and trailing edge of an excitation pulse generates a reflection from a defect, so that a unique pair of reflections is associated with each defect. In the present alternative technique, the processing of the measured reflection signal includes computation of the autocorrelation function R(tau) identical with fx(t)x(t-tau)dt where t is time, x(t) is the measured reflection signal at time t, and taus is the correlation interval. The integration is performed over a measurement time interval short enough to enable identification and location of a defect within the corresponding spatial interval along the cable. Typically, where there is a defect, R(tau) exhibits a negative peak having maximum magnitude for tau in the vicinity of T. This peak can be used as a means of identifying a leading-edge/trailing-edge reflection pair. For a given spatial interval, measurements are made and R(tau) computed, as described above, for pulse durations T ranging from the minimum to the maximum value. The advantage of doing this is that the effective signal-to-noise ratio may be significantly increased over that attainable by use of a fixed pulse duration T.

Lucena, Angel; Mullinex, Pam; Huang, PoTien; Santiago, Josephine; Mata, Carlos; Zavala, Carlos; Lane, John

2008-01-01

385

Development overview of the revised NASA Ultra Long Duration Balloon  

NASA Astrophysics Data System (ADS)

The desire for longer duration stratospheric flights at constant float altitudes for heavy payloads has been the focus of the development of the National Aeronautics and Space Administration’s (NASA) Ultra Long Duration Balloon (ULDB) effort. Recent efforts have focused on ground testing and analysis to understand the previously observed issue of balloon deployment. A revised approach to the pumpkin balloon design has been tested through ground testing of model balloons and through two test flights. The design approach does not require foreshortening, and will significantly reduce the balloon handling during manufacture reducing the chances of inducing damage to the envelope. Successful ground testing of model balloons lead to the fabrication and test flight of a ˜176,000 m3 (˜6.2 MCF Million Cubic Foot) balloon. Pre-flight analytical predictions predicted that the proposed flight balloon design to be stable and should fully deploy. This paper provides an overview of this first test flight of the revised Ultra Long Duration Balloon design which was a short domestic test flight from Ft. Sumner, NM, USA. This balloon fully deployed, but developed a leak under pressurization. After an extensive investigation to the cause of the leak, a second test flight balloon was fabricated. This ˜176,000 m3 (˜6.2 MCF) balloon was flown from Kiruna, Sweden in June of 2006. Flight results for both test flights, including flight performance are presented.

Cathey, H. M.

2008-11-01

386

[Pharmaceutical intervention in duration of antimicrobial treatment at hospital ambit].  

PubMed

Objective. To estimate the acceptance of the pharmaceutical intervention in controlling duration of antimicrobial therapy and to evaluate their impact on optimizing the treatment. Methods. Prospective observational study for two years in a General University Hospital. For the patients record, we followed non critical adult patients with antibiotic treatment. When the duration of antimicrobial treatment not complied with established criteria for each antibiotic and pathology, there was a communication with the physician, at which is recommended to assess the need for continue treatment. The acceptance of pharmaceutical intervention was collected and afterwards we analyzed the impact of this work by antimicrobial consumption and incidence of Clostridium difficile. Results. In 122 patients the pharmacist made a pharmaceutical intervention due to prolonged antibiotic treatment. The most prevalent antibiotics were ?-lactams, specifically meropenem. The intravenous administration was more frequent. In 77 cases it was decided to recommend the suspension of treatment, we conducted an orally prospective intervention at 70.15 % and the rest of interventions were written. Acceptance was 65.95 % and 65.00%, respectively. During the study period, the DDD of the antimicrobials decreased by 8.89% and expenditure on antimicrobials one 40.12%. The incidence of C. difficile was stable. Conclusions. In a hospital, a pharmaceutical counselling program on the duration of antimicrobial therapy is well accepted by the prescriber physician, but it must be improved. The route of information does not affect the degree of acceptance. These actions could involve a reduction of antimicrobial consumption. PMID:25229371

Morante, M; Matoses-Chirivella, C; Rodríguez-Lucena, F J; Del Moral, J M; Ruiz-García, M; Navarro-Ruiz, A

2014-09-01

387

Analysis models for variables associated with breastfeeding duration  

PubMed Central

OBJECTIVE To analyze the factors associated with breastfeeding duration by two statistical models. METHODS A population-based cohort study was conducted with 86 mothers and newborns from two areas primary covered by the National Health System, with high rates of infant mortality in Vitória, Espírito Santo, Brazil. During 30 months, 67 (78%) children and mothers were visited seven times at home by trained interviewers, who filled out survey forms. Data on food and sucking habits, socioeconomic and maternal characteristics were collected. Variables were analyzed by Cox regression models, considering duration of breastfeeding as the dependent variable, and logistic regression (dependent variables, was the presence of a breastfeeding child in different post-natal ages). RESULTS In the logistic regression model, the pacifier sucking (adjusted Odds Ratio: 3.4; 95%CI 1.2-9.55) and bottle feeding (adjusted Odds Ratio: 4.4; 95%CI 1.6-12.1) increased the chance of weaning a child before one year of age. Variables associated to breastfeeding duration in the Cox regression model were: pacifier sucking (adjusted Hazard Ratio 2.0; 95%CI 1.2-3.3) and bottle feeding (adjusted Hazard Ratio 2.0; 95%CI 1.2-3.5). However, protective factors (maternal age and family income) differed between both models. CONCLUSIONS Risk and protective factors associated with cessation of breastfeeding may be analyzed by different models of statistical regression. Cox Regression Models are adequate to analyze such factors in longitudinal studies. PMID:24142312

dos S., Edson Theodoro; Zandonade, Eliana; Emmerich, Adauto Oliveira

2013-01-01

388

Physiology, medicine, long-duration space flight and the NSBRI  

NASA Technical Reports Server (NTRS)

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. c2003 International Astronautical Federation. Published by Elsevier Science Ltd. All rights reserved.

McPhee, J. C.; White, R. J.

2003-01-01

389

Physiology, Medicine, Long-Duration Space Flight and the NSBRI  

NASA Astrophysics Data System (ADS)

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.

White, R. J.; Sutton, J. P.; McPhee, J. C.

390

Physiology, medicine, long-duration space flight and the NSBRI  

NASA Astrophysics Data System (ADS)

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.

McPhee, J. C.; White, R. J.

2003-08-01

391

Duration of effect of single daily dose methyldopa therapy.  

PubMed Central

1 Methyldopa has a short plasma half-life, but longer duration of antihypertensive effect. A single bedtime dose of methyldopa has been recommended to improve compliance and decrease side effects. 2 This double-blind crossover study was designed to determine the duration of antihypertensive effect of methyldopa by comparing hourly supine and standing blood pressures, throughout the day during placebo, single morning dose, and single evening dose methyldopa therapy in 10 patients. The major side effects, drowsiness and dry mouth were assessed by visual analogue scale. Exercise blood pressures were measured 6, 12, 18 and 24 h after the dose. 3 The antihypertensive effect of methyldopa peaked after 6-9 h and declined thereafter with a half-life of approximately 10 h. Little antihypertensive effect remained 24-26 h after the dose. The time course of the reduction in blood pressure during exercise and of the major side effects paralleled the antihypertensive effects. 4 The results suggest that the duration of antihypertensive effect of methyldopa is long enough to permit twice daily dosing, but that single daily dosing cannot be recommended for most patients. The study illustrates the importance of knowing the time of the last methyldopa dose when assessing blood pressure measurements in patients taking the drug. PMID:7093115

Wright, J M; Orozco-Gonzalez, M; Polak, G; Dollery, C T

1982-01-01

392

Adaptive Sensing and Transmission Durations for Cognitive Radios  

E-print Network

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.

Wessam Afifi; Ahmed Sultan; Mohammed Nafie

2010-12-02

393

Duration of Loxosceles reclusa Venom Detection by ELISA from Swabs  

PubMed Central

BACKGROUND Diagnosis of Loxosceles reclusa envenomations is currently based upon clinical presentation. An enzyme-linked immunosorbent assay (ELISA) can detect surface Loxosceles venom at the envenomation site, allowing diagnostic confirmation. The length of time that venom on the skin is recoverable non-invasively is unknown. MATERIALS AND METHODS To investigate duration of recoverable venom antigen, whole venom and fractionated sphingomyelinase D venom aliquots were injected subcutaneously in New Zealand White rabbits. Cotton and Dacron swabs were compared for venom recovery over a 21-day period using a surface swab technique. RESULTS Significant amounts of Loxosceles reclusa antigen were found on the surface of rabbit skin after experimental injection of whole venom and sphingomyelinase D. The duration of recoverable antigen using this experimental model appears to be at least two weeks and as long as 21 days in some cases. CONCLUSIONS Because the duration of the recoverable antigen is seen to be at least two weeks, the ELISA venom test appears capable of detecting venom on most patients presenting with Loxosceles envenomations. This detection system will allow the physician more accurate determination of whether the lesion is from a brown recluse spider or some other agent that can cause this type of necrotic ulcer. PMID:19967916

McGLASSON, DAVID L; GREEN, JONATHON A; STOECKER, WILLIAM V; BABCOCK, JAMES L; CALCARA, DAVID A

2011-01-01

394

Marked Exacerbation of Orthostatic Intolerance After Long-vs. Short-Duration Spaceflight in Veteran Astronauts  

E-print Network

Marked Exacerbation of Orthostatic Intolerance After Long- vs. Short-Duration Spaceflight-duration spaceflight is about 20%. How- ever, the incidence after long-duration spaceflight was unknown. The purpose-duration (129­190 days) spaceflights and compared these data with data obtained during stand tests before

395

Association between Screen Viewing Duration and Sleep Duration, Sleep Quality, and Excessive Daytime Sleepiness among Adolescents in Hong Kong.  

PubMed

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

Mak, Yim Wah; Wu, Cynthia Sau Ting; Hui, Donna Wing Shun; Lam, Siu Ping; Tse, Hei Yin; Yu, Wing Yan; Wong, Ho Ting

2014-01-01

396

Standard metabolic rate is associated with gestation duration, but not clutch size, in speckled cockroaches Nauphoeta cinerea  

PubMed Central

Summary Metabolic rate varies significantly between individuals, and these differences persist even when the wide range of biotic and abiotic factors that influence metabolism are accounted for. It is important to understand the life history implications of variation in metabolic rate, but they remain poorly characterised despite a growing body of work examining relationships between metabolism and a range of traits. In the present study we used laboratory-bred families (one sire to three dams) of Nauphoeta cinerea (Olivier) (speckled cockroaches) to examine the relationship between standard metabolic rate (SMR) and reproductive performance (number of offspring and gestation duration). We show that SMR is negatively associated with female gestation duration. Age at mating is negatively associated with gestation duration for females, and mass is negatively associated with the average gestation duration of the females a male was mated with. In addition to the results in the current literature, the results from the present study suggest that the association between metabolism and life history is more complex than simple relationships between metabolism and various fitness traits. Future work should consider longitudinal, ontogenetic as well as selective and quantitative genetic breeding approaches to fully examine the associations between metabolism and fitness. PMID:23259052

Schimpf, Natalie G.; Matthews, Philip G. D.; White, Craig R.

2012-01-01

397

The signal of aerosol-induced changes in sunshine duration records: A review of the evidence  

NASA Astrophysics Data System (ADS)

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.

Sanchez-Romero, A.; Sanchez-Lorenzo, A.; Calbó, J.; González, J. A.; Azorin-Molina, C.

2014-04-01

398

An Unorthodox X-Class Long-duration Confined Flare  

NASA Astrophysics Data System (ADS)

We report the observation of an X-class long-duration flare which is clearly confined. It appears as a compact-loop flare in the traditional EUV passbands (171 and 195 Å), but in the passbands sensitive to flare plasmas (94 and 131 Å), it exhibits a cusp-shaped structure above an arcade of loops like other long-duration events. Inspecting images in a running difference approach, we find that the seemingly diffuse, quasi-static cusp-shaped structure consists of multiple nested loops that repeatedly rise upward and disappear approaching the cusp edge. Over the gradual phase, we detect numerous episodes of loop rising, each lasting minutes. A differential emission measure analysis reveals that the temperature is highest at the top of the arcade and becomes cooler at higher altitudes within the cusp-shaped structure, contrary to typical long-duration flares. With a nonlinear force-free model, our analysis shows that the event mainly involves two adjacent sheared arcades separated by a T-type hyperbolic flux tube (HFT). One of the arcades harbors a magnetic flux rope, which is identified with a filament that survives the flare owing to the strong confining field. We conclude that a new emergence of magnetic flux in the other arcade triggers the flare, while the preexisting HFT and flux rope dictate the structure and dynamics of the flare loops and ribbons during the long-lasting decay phase, and that a quasi-separatrix layer high above the HFT could account for the cusp-shaped structure.

Liu, Rui; Titov, Viacheslav S.; Gou, Tingyu; Wang, Yuming; Liu, Kai; Wang, Haimin

2014-07-01

399

Changes in motoneuron afterhyperpolarization duration in stroke survivors.  

PubMed

Hemispheric brain injury resulting from a stroke is often accompanied by muscle weakness in limbs contralateral to the lesion. In the present study, we investigated whether weakness in contralesional hand muscle in stroke survivors is partially attributable to alterations in motor unit activation, including alterations in firing rate modulation range. The afterhyperpolarization (AHP) potential of a motoneuron is a primary determinant of motoneuron firing rate. We examined differences in AHP duration in motoneurons innervating paretic and less impaired (contralateral) limb muscles of hemiparetic stroke survivors as well as in control subjects. A novel surface EMG (sEMG) electrode was used to record motor units from the first dorsal interosseous muscle. The sEMG data were subsequently decomposed to derive single-motor unit events, which were then utilized to produce interval (ISI) histograms of the motoneuron discharges. A modified version of interval death rate (IDR) analysis was used to estimate AHP duration. Results from data analyses performed on both arms of 11 stroke subjects and in 7 age-matched control subjects suggest that AHP duration is significantly longer for motor units innervating paretic muscle compared with units in contralateral muscles and in units of intact subjects. These results were supported by a coefficient of variation (CV) analysis showing that paretic motor unit discharges have a lower CV than either contralateral or control units. This study suggests that after stroke biophysical changes occur at the motoneuron level, potentially contributing to lower firing rates and potentially leading to less efficient force production in paretic muscles. PMID:24920018

Suresh, Aneesha K; Hu, Xiaogang; Powers, Randall K; Heckman, C J; Suresh, Nina L; Rymer, William Zev

2014-09-15

400

Infant feeding practices and breastfeeding duration in Japan: A review.  

PubMed

The Japanese health system places great emphasis on healthy development. However, the prevalence of Exclusive Breastfeeding at one month postpartum between 1980 and 2005 has remained unchanged, fluctuating between 42% and 49%. At the same time, the Any Breastfeeding prevalence has gradually increased from about 80% to 95%. In 2010, the latest national breastfeeding report showed that 'exclusive' and 'any' breastfeeding rates have improved. However, as the World Health Organization (WHO) definition of breastfeeding practices was not used in this study or in other national surveys, it is difficult to interpret these latest results. While the Japanese government has launched several promotion projects, there have been few studies and reviews of risk factors that influence breastfeeding duration. The objectives of this review were to summarise the factors that have influenced the duration of breastfeeding in Japan to provide information relevant to breastfeeding promotion programs. A search of electronic databases in Japanese and English was undertaken up to 2011. The inclusion criteria for this review were studies that focused on infant feeding practices and targeted Japanese mothers, fathers, or health professionals, but excluded mothers' friends and peer groups. In total, 12 articles were selected for the final analysis. Smoking status, low birth weight of infants and maternal perceptions of insufficient breast milk supply were negative influences on breastfeeding duration, while support from husbands/partners is associated with continued breastfeeding. Some factors that have been found to be associated with breastfeeding in other countries, including maternal age, family income, maternal educational levels, and living with grandparents of infants have not been confirmed in Japan. While the national breastfeeding rates were higher than other countries of similar health status, inconsistent knowledge of breastfeeding benefits and inappropriate hospital practices remain in Japan may be associated with increased the use of infant formula and reduced breastfeeding duration. Most of the studies reviewed were cross-sectional in design, with only a limited number of cohort studies. Also many published studies used small sample sizes. Cohort studies of infant feeding practices with larger sample sizes are required to monitor trends in rates and risk factors for breastfeeding outcomes. PMID:23098220

Inoue, Madoka; Binns, Colin W; Otsuka, Keiko; Jimba, Masamine; Matsubara, Manami

2012-01-01

401

Psychology and culture during long-duration space missions  

NASA Astrophysics Data System (ADS)

The objective of this paper is twofold: (a) to review the current knowledge of cultural, psychological, psychiatric, cognitive, interpersonal, and organizational issues that are relevant to the behavior and performance of astronaut crews and ground support personnel and (b) to make recommendations for future human space missions, including both transit and planetary surface operations involving the Moon or Mars. The focus will be on long-duration missions lasting at least six weeks, when important psychological and interpersonal factors begin to take their toll on crewmembers. This information is designed to provide guidelines for astronaut selection and training, in-flight monitoring and support, and post-flight recovery and re-adaptation.

Kanas, N.; Sandal, G.; Boyd, J. E.; Gushin, V. I.; Manzey, D.; North, R.; Leon, G. R.; Suedfeld, P.; Bishop, S.; Fiedler, E. R.; Inoue, N.; Johannes, B.; Kealey, D. J.; Kraft, N.; Matsuzaki, I.; Musson, D.; Palinkas, L. A.; Salnitskiy, V. P.; Sipes, W.; Stuster, J.; Wang, J.

2009-04-01

402

Flash duration effect in one-sided thermal imaging.  

SciTech Connect

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.

Sun, J. G.; Benz, J.; Energy Technology

2005-01-01

403

[Effect of temperature on developmental duration of Amblyseius cucumeris].  

PubMed

With Polyphagotarsonemus latus as its prey, the developmental duration of Amblyseius cucumeris was 13.02, 9.61, 5.96, 5.26, 4.65, 4.78, and 5.80 days at 18, 20, 23, 25, 28, 30, and 31 degrees C, respectively. The eggs of A. cucumeris could not hatch at 32 degrees C. The lower and upper developmental thresholds and the optimum developmental temperature of A. cucumeris from eggs to adults were 12.77 degrees C, 33.50 degrees C and 23.87 degrees C, respectively. PMID:15031928

Li, Jiamin; Lü, Jiale; Qu, Yunfang; Yang, Yanyun; Wu, Qianhong

2003-12-01

404

Passive stabilization of the Long Duration Exposure Facility (LDEF)  

NASA Technical Reports Server (NTRS)

The results of a study on the application of the magnetically anchored rate damper to gravity gradient stabilization of the Long Duration Exposure Facility (LDEF) are presented. The analyses and simulations required to investigate the use of an existing viscous magnetic rate damper for rate stabilizing the LDEF spacecraft were performed. The following tasks were included: linear performance estimates, capture and damper requirements, and performance prediction. Each of these tasks was performed for two gravity gradient stabilization configurations; an axisymmetric configuration for two-axis (pitch and roll) stability; and a non-axisymmetric configuration for three-axis stability. The results are presented by stabilization configuration.

Das, A.

1974-01-01

405

Foot Reaction Forces during Long Duration Space Flight  

NASA Technical Reports Server (NTRS)

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.

Gopalakrishnan, R.; Rice, A. J.; Genc, K. O.; Maender, C. C.; Kuklis, M. M.; Humphreys, B.; Cavanagh, P. R.

2008-01-01

406

Simulation modeling for long duration spacecraft control systems  

NASA Technical Reports Server (NTRS)

The use of simulation is described and it is contrasted to analytical solution techniques for evaluation of analytical reliability models. The role importance sampling plays in simulation of models of this type was also discussed. The simulator tool used for our analysis is described. Finally, the use of the simulator tool was demonstrated by applying it to evaluate the reliability of a fault tolerant hypercube multiprocessor intended for spacecraft designed for long duration missions. The reliability analysis was used to highlight the advantages and disadvantages offered by simulation over analytical solution of Markovian and non-Markovian reliability models.

Boyd, Mark A.; Bavuso, Salvatore J.

1993-01-01

407

Development Overview of the Revised NASA Ultra Long Duration Balloon  

NASA Technical Reports Server (NTRS)

The development of the National Aeronautics and Space Administration s (NASA) Ultra Long Duration Balloon (ULDB) has made significant strides in addressing the deployment issues experienced in the scaling up of the balloon structure. This paper concentrates on the super-pressure balloon developments that have been, and are currently being planned by the NASA Balloon Program Office at Goddard Space Flight Center s Wallops Flight Facility. The goal of the NASA ULDB development project is to attempt to extend the potential flight durations for large scientific balloon payloads. A summary of the February 2005 test flight from Ft. Sumner, New Mexico will be presented. This test flight spurred a number of investigations and advancements for this project. The development path has pursued some new approaches in the design, analysis, and testing of the balloons. New issues have been ideEti6ed throu& both analysis md testing. These have been addressed in the design stage before the next balloon construction was begun. This paper will give an overview of the recent history for this effort and the development approach pursued for ULDB. A description of the balloon design, including the modifications made as a result of the lessons learned, will be presented. Areas to be presented include the design approach, deployment issues that have been encountered and the proposed solutions, ground testing, photogrammetry, and an analysis overview. Test flight planning and considerations will be presented including test flight safety. An extended duration test flight of the National Aeronautics and Space Administration s Ultra Long Duration Balloon is planned for the May/June 2006 time frame. This flight is expected to fly from Sweden to either Canada or Alaska. Preliminary results of this flight will be presented as available. Future plans for both ground testing and additional test flights will also be presented. Goals of the future test flights, which are staged in increments of increasing suspended load and altitude, will be presented. This will include the projected balloon volumes, payload capabilities, test flight locations, and proposed flight schedule.

Cathey, H. M.; Gregory, D; Young, L.; Pierce, D.

2006-01-01

408

Quantiles Regression Approach to Identifying the Determinant of Breastfeeding Duration  

NASA Astrophysics Data System (ADS)

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.

Mahdiyah; Norsiah Mohamed, Wan; Ibrahim, Kamarulzaman

409

Cultural Complexity  

Microsoft Academic Search

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

Wolfgang Fikentscher

1998-01-01

410

Moving time: The influence of action on duration perception.  

PubMed

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 others' reactions to us may be briefer than we believe. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:25089534

Press, Clare; Berlot, Eva; Bird, Geoffrey; Ivry, Richard; Cook, Richard

2014-10-01

411

r-process kilonova emission accompanying short-duration GRBs  

NASA Astrophysics Data System (ADS)

Our recent HST observations of the short-duration GRB130603B showed an infrared excess, about ten days after the burst, consistent with expectations from models of an emerging 'kilonova' driven by the radioactive decay of newly-synthesised r-process elements. This directly supports the compact object merger hypothesis for short-duration GRBs, in which ejected neutron star material powers a radioactive transient. The discovery also provides a new, quasi-isotropic, electromagnetic localisation signature of the most promising class of gravitational wave (GW) sources for detection with the next generation of detectors, and suggests that kilonovae of this sort are likely sites of substantial (perhaps dominant) production of r-process elements in the universe. However, the ubiquity and range of behaviour of these events is entirely unknown. We need to establish their properties to inform searches of GW error boxes and quantify their contribution to the heavy element nucleosynthesis budget. Here we propose ToO observations a low-redshift (z<~0.35) SGRB localised during cycle 22 to search for and characterise more fully any similar kilonova signal.

Tanvir, Nial

2014-10-01

412

Hippocampal volume is inversely related to PTSD duration.  

PubMed

Numerous imaging studies have reported smaller hippocampal volumes in patients with PTSD. To investigate whether decreased hippocampal volume is associated with PTSD chronicity, independent of age, we used hierarchical linear regression to examine the relationship between PTSD duration (estimated from the amount of time that had elapsed since the traumatic event; mean=17 years; range=6-36 years) and hippocampal volume, adjusting for age and other factors. Freesurfer version 4.5 was used to quantify the volumes of the hippocampus and the caudate nucleus, which served as a "control" region, from the 1.5T Magnetic Resonance Images (MRI) of 55 combat veterans (mean age 45±9 years) with chronic and current PTSD. PTSD duration was significantly associated with right hippocampal volume (?=-0.34, t=-2.40, P=0.02) after accounting for intracranial volume, age, gender (entered in the first step) and comorbidities (e.g., early life trauma, current major depression, history of substance abuse/dependence, psychotropic medication use, entered in the second step). This finding provides support for the potential neurotoxic effects of PTSD on hippocampal volume. PMID:24742925

Chao, Linda L; Yaffe, Kristine; Samuelson, Kristin; Neylan, Thomas C

2014-06-30

413

Long Duration Performance of High Temperature Irradiation Resistant Thermocouples  

SciTech Connect

Many advanced nuclear reactor designs require new fuel, cladding, and structural materials. Data are needed to characterize the performance of these new materials in high temperature, radiation conditions. However, traditional methods for measuring temperature inpile degrade at temperatures above 1100 ºC. To address this instrumentation need, the Idaho National Laboratory (INL) developed and evaluated the performance of a high temperature irradiation-resistant thermocouple that contains alloys of molybdenum and niobium. To verify the performance of INL’s recommended thermocouple design, a series of high temperature (from 1200 to 1800 ºC) long duration (up to six months) tests has been initiated. This paper summarizes results from the tests that have been completed. Data are presented from 4000 hour tests conducted at 1200 and 1400 ºC that demonstrate the stability of this thermocouple (less than 2% drift). In addition, post test metallographic examinations are discussed which confirm the compatibility of thermocouple materials throughout these long duration, high temperature tests.

Rempe, Joy L; Knudson, D. L.; Condie, K. G.; Wilkins, S. C.

2007-05-01

414

Dietary Support of Extended-Duration Bed Rest Studies  

NASA Technical Reports Server (NTRS)

Dietary control and nutrient intake are critical aspects of any metabolic study, but this is especially true in the case of bed rest studies. We sought to define nutrient requirements, develop menus, and implement them in a series of three long-duration bed rest studies. With regard to energy intake, the goal was to maintain subject body weight to within 3% of their body weight on day 3 of bed rest (after fluid shift had occurred). For other nutrients, intakes were based on the NASA space flight nutritional requirements (with some adaptations based on the ground-based model used here). A secondary goal was to develop menus with foods similar to those expected to be approved for space flight (however, this was relaxed to attain desired nutrient intakes). This paper also describes the role of the research dietitian as part of the multi-disciplinary team and the importance of the metabolic kitchen staff. It also provides insight into some of the dietary challenges that arise during extended-duration bed rest studies. Regardless of the overall objective of the study, nutrition must be carefully planned, implemented, and monitored for results to be uncompromised.

Inniss, A. M.; Rice, B. L.; Smith, S. M.

2006-01-01

415

Postplacental or delayed levonorgestrel intrauterine device insertion and breastfeeding duration  

PubMed Central

BACKGROUND The objective was to assess the effect of timing of postpartum levonorgestrel-releasing IUD insertion on breastfeeding continuation. STUDY DESIGN Women interested in using a levonorgestrel IUD postpartum were randomized to immediate postplacental insertion (postplacental group) or insertion 6–8 weeks after vaginal delivery (delayed group). Duration and exclusivity of breastfeeding were assessed at 6–8 weeks, 3 months, and 6 months postpartum. Only women who received an IUD were included in this analysis. RESULTS Breastfeeding was initiated by 32/50 (64%) of women receiving a postplacental IUD and 27/46 (58.7%) of women receiving a delayed IUD (p=0.59). More women in the delayed group compared to the postplacental group continued to breastfeed at 6–8 weeks (16/46 vs 15/50, p=0.62), 3 months (13/46 vs 7/50, p=0.13), and 6 months postpartum (11/46 vs 3/50, p=0.02). The results did not differ when only women who initiated breastfeeding or only primiparous women with no prior breastfeeding experience were analyzed. CONCLUSIONS Immediate postplacental insertion of the levonorgestrel IUD is associated with shorter duration of breastfeeding and less exclusive breastfeeding. Further studies are needed of the effects of early initiation of progestin-only methods on women’s lactation experience. PMID:22018124

Chen, Beatrice A.; Reeves, Matthew F.; Creinin, Mitchell D.; Schwarz, E. Bimla

2011-01-01

416

On the nature of the short-duration GRB 050906  

NASA Astrophysics Data System (ADS)

We present deep optical and infrared (IR) observations of the short-duration GRB 050906. Although no X-ray or optical/IR afterglow was discovered to deep limits, the error circle of the gamma-ray burst (GRB) (as derived from the Swift Burst Alert Telescope, or BAT) is unusual in containing the relatively local starburst galaxy IC328. This makes GRB 050906 a candidate burst from a soft gamma-ray repeater (SGR), similar to the giant flare from SGR 1806-20. The probability of chance alignment of a given BAT position with such a galaxy is small (<~1 per cent), although the size of the error circle (2.6arcmin radius) is such that a higher z origin cannot be ruled out. Indeed, the error circle also includes a moderately rich galaxy cluster at z = 0.43, which is a plausible location for the burst given the apparent preference that short-duration GRBs have for regions of high mass density. No residual optical or IR emission has been observed, in the form of either an afterglow or a later time emission from any associated supernova-like event. We discuss the constraints these limits place on the progenitor of GRB 050906 based on the expected optical signatures from both SGRs and merging compact object systems. Based on observations made with European Southern Observatory (ESO) telescopes at the Paranal Observatory under programme ID 075.D-0261. E-mail: a.j.levan@warwick.ac.uk

Levan, A. J.; Tanvir, N. R.; Jakobsson, P.; Chapman, R.; Hjorth, J.; Priddey, R. S.; Fynbo, J. P. U.; Hurley, K.; Jensen, B. L.; Johnson, R.; Gorosabel, J.; Castro-Tirado, A. J.; Jarvis, M.; Watson, D.; Wiersema, K.

2008-02-01

417

Annual flow duration curves assessment in ephemeral small basins  

NASA Astrophysics Data System (ADS)

Flow duration curve (FDC) represents a comprehensive signature of temporal runoff variability often used to synthesize catchment rainfall-runoff responses. A new model, the ModABa (MODel for Annual flow duration curves assessment in ephemeral small BAsins), is here introduced. It can be thought as a wide mosaic whose tesserae are frameworks, models or conceptual schemes separately developed in different studies and harmoniously interconnected with the final aim of reproducing the annual FDC in intermittent small catchments. Two separated seasons within the hydrological year are distinguished: a dry season, characterized by absence of streamflow, and a non-zero season. Streamflow is disaggregated into a subsurface component and a surface component that, in turn, is considered formed by two different contributions: impervious runoff and surface runoff from permeable areas induced by heavy rains. The FDCs of the two streamflow components are first separately and differently computed, and then combined to obtain the non-zero FDC. This last, together with the estimated probability of null streamflow, allows the annual FDC assessment through the theory of total probability. The ModABa is here tested on a small Italian catchment and the results show how the model, once calibrated, is able to accurately reproduce the empirical FDC for the analyzed case, starting from easily derivable parameters and commonly available climatic data. In this sense, the model reveals itself as a valid tool, potentially suitable for predictions at ungauged basins in a regionalization framework.

Pumo, D.; Viola, F.; La Loggia, G.; Noto, L. V.

2014-11-01

418

Advanced Water Recovery Technologies for Long Duration Space Exploration Missions  

NASA Technical Reports Server (NTRS)

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.

Liu, Scan X.

2005-01-01

419

Reciprocity in long pulse duration laser interactions with polymers  

NASA Astrophysics Data System (ADS)

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 µs 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.

Marchant, A. L.; Snelling, H. V.

2012-05-01

420

Intercultural crew issues in long-duration spaceflight  

NASA Technical Reports Server (NTRS)

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.

Kraft, Norbert O.; Lyons, Terence J.; Binder, Heidi

2003-01-01

421

Investigating An X-Class Long-Duration Confined Flare  

NASA Astrophysics Data System (ADS)

We report the observation of an X-class long-duration flare which is clearly confined. It appears as a compact-loop 50 Mm high in projection) flare in the traditional EUV passbands (171 and 195A}; ~1 MK), but in the passbands sensitive to flare plasmas (94 and 131A; 6-10 MK), it exhibits a cusp-shaped structure above an arcade of loops 100 Mm high in projection) like other long-duration events. Inspecting images in a running difference approach, we find that the seemingly diffuse, quasi-static cusp-shaped structure actually consists of multiple nested loops that repeatedly rise upward and disappear approaching the cusp point. Over the gradual phase of the flare, we detect numerous episodes of loop rising, each lasting minutes. A differential emission measure analysis reveals that the temperature is highest at the top of the arcade and becomes cooler at higher altitudes within the cusp-shaped structure. These features are contrary to typical long-duration flares that conform to the standard flare model. With a nonlinear force-free reconstruction of the active region, our analysis of the photospheric squashing factor $Q$ shows that the configuration has locally a tri-polar structure, in the middle of which the negative polarity is divided in half by a high-$Q$ line. The respective halves belong to two adjacent sheared arcades, one of which harbors a magnetic flux rope. The indicated high-Q line is a footprint of a hyperbolic flux tube (HFT) where two quasi-separatrix layers (QSLs) adjoin each other at a T-type junction passing through the joint arcades' apex. Comparing UV 1600A flare ribbons with the photospheric Q-maps at close times, we conclude that the emergence of a new magnetic flux within the arcade void of flux rope triggers the flare, while the preexisting T-type HFT and flux rope dictate the structure and dynamics of the observed flare loops and ribbons. The flux rope fails to escape owing to a strong confining field but contributes to the long-lasting gradual phase with the dissipation of QSL currents.

Liu, Rui; Titov, Viacheslav; Gou, Tingyu; Wang, Yuming; Liu, Kai; Wang, Haimin

2014-06-01

422

Update on imatinib for gastrointestinal stromal tumors: duration of treatment  

PubMed Central

Gastrointestinal stromal tumors (GISTs) are the most common sarcoma of the gastrointestinal tract, with transformation typically driven by activating mutations of c-KIT and less commonly platelet-derived growth factor receptor alpha (PDGFRA). Successful targeting of c-KIT and PDGFRA with imatinib, a tyrosine kinase inhibitor (TKI), has had a major impact in advanced GIST and as an adjuvant and neoadjuvant treatment. If treatment with imatinib fails, further lines of TKI therapy have a role, but disease response is usually only measured in months, so strategies to maximize the benefit from imatinib are paramount. Here, we provide an overview of the structure and signaling of c-KIT coupled with a review of the clinical trials of imatinib in GIST. In doing so, we make recommendations about the duration of imatinib therapy and suggest how best to utilize imatinib in order to improve patient outcomes in the future. PMID:23935374

Linch, Mark; Claus, Jeroen; Benson, Charlotte

2013-01-01

423

A reexamination of long-duration radial IMF events  

NASA Astrophysics Data System (ADS)

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 (>4 h) using the OMNI solar wind data. During the events, the IMF magnitude, solar wind speed, 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 the 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.

Pi, Gilbert; Shue, Jih-Hong; Chao, Jih-Kwin; N?me?ek, Zdenek; Å afránková, Jana; Lin, Chia-Hsien

2014-09-01

424

The preliminary Long Duration Exposure Facility (LDEF) materials data base  

NASA Technical Reports Server (NTRS)

A preliminary Long Duration Exposure Facility (LDEF) Materials Data Base was developed by the LDEF Materials Special Investigation Group (MSIG). The LDEF Materials Data Base is envisioned to eventually contain the wide variety and vast quantity of materials data generated for LDEF. The data is searchable by optical, thermal, and mechanical properties, exposure parameters (such as atomic oxygen flux), and author(s) or principal investigator(s). The LDEF Materials Data Base was incorporated into the Materials and Processes Technical Information System (MAPTIS). MAPTIS is a collection of materials data which was computerized and is available to engineers, designers, and researchers in the aerospace community involved in the design and development of spacecraft and related hardware. This paper describes the LDEF Materials Data Base and includes step-by-step example searches using the data base. Information on how to become an authorized user of the system is included.

Funk, Joan G.; Strickland, John W.; Davis, John M.

1992-01-01

425

The Electron Calorimeter (ECAL) Long Duration Balloon Experiment  

NASA Technical Reports Server (NTRS)

Accurate measurements of the cosmic ray electron energy spectrum in the energy region 50 GeV to greater than 1 TeV may reveal structure caused by the annihilation of exotic dark matter particles and/or individual cosmic ray sources. Here we describe a new long duration balloon (LDB) experiment, ECAL, optimized to directly measure cosmic ray electrons up to several TeV. ECAL includes a double layer silicon matrix, a scintillating optical fiber track imager, a neutron detector and a fully active calorimeter to identify more than 90% of the incident electrons with an energy resolution of about 1.7% while misidentifying only 1 in 200,000 protons and 0.8% of secondary gamma rays as electrons. Two ECAL flights in Antarctica are planned for a total exposure of 50 days with the first flight anticipate for December 2009.

Guzik, T. G.; Adams, J. H.; Bashindzhagyan, G.; Binns, W. R.; Chang, J.; Cherry, M. L.; Christl, M.; Dowkontt, P.; Ellison, B.; Isbert, J. B.; Israel, M. H.; Korotkova, N.; Panasyuk, M.; Panov, A.; Sokolskaya, N.; Stewart, M.; Watts, J.; Wefel, P.; Zatsepin, V.

2007-01-01

426

Workshop on Exercise Prescription for Long-Duration Space Flight  

NASA Technical Reports Server (NTRS)

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.

Harris, Bernard A., Jr. (editor); Stewart, Donald F. (editor)

1989-01-01

427

15 CFR Supplement No. 1 to Part 716 - Notification, Duration and Frequency of Inspections  

...Notification, Duration and Frequency of Inspections No. Supplement No. 1 to Part 716 Commerce and Foreign Trade Regulations...INSPECTIONS OF DECLARED FACILITIES Pt. 716, Supp. 1 Supplement No. 1 to Part 716—Notification, Duration and...

2014-01-01

428

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...INSPECTIONS OF DECLARED FACILITIES Pt. 716, Supp. 1 Supplement No. 1 to Part 716—Notification, Duration and...

2011-01-01

429

15 CFR Supplement No. 1 to Part 716 - Notification, Duration and Frequency of Inspections  

Code of Federal Regulations, 2013 CFR

...Notification, Duration and Frequency of Inspections No. Supplement No. 1 to Part 716 Commerce and Foreign Trade Regulations...INSPECTIONS OF DECLARED FACILITIES Pt. 716, Supp. 1 Supplement No. 1 to Part 716—Notification, Duration and...

2013-01-01

430

15 CFR Supplement No. 1 to Part 716 - Notification, Duration and Frequency of Inspections  

Code of Federal Regulations, 2012 CFR

...Notification, Duration and Frequency of Inspections No. Supplement No. 1 to Part 716 Commerce and Foreign Trade Regulations...INSPECTIONS OF DECLARED FACILITIES Pt. 716, Supp. 1 Supplement No. 1 to Part 716—Notification, Duration and...

2012-01-01

431

15 CFR Supplement No. 1 to Part 716 - Notification, Duration and Frequency of Inspections  

Code of Federal Regulations, 2010 CFR

...Notification, Duration and Frequency of Inspections No. Supplement No. 1 to Part 716 Commerce and Foreign Trade Regulations...INSPECTIONS OF DECLARED FACILITIES Pt. 716, Supp. 1 Supplement No. 1 to Part 716—Notification, Duration and...

2010-01-01

432

Development of Ultra Long Duration Local Anesthetic Agents in a Rat Model.  

National Technical Information Service (NTIS)

Lecithin-coated tetracaine microcrystals provide an ultra long duration local anesthetic effect without causing toxicity to surrounding tissues or nerves. Lecithin-coated buplvacaine microcrystals also appear to have an ultra long duration local anestheti...

B. H. Boedeker, M. Kline

1994-01-01

433

38 CFR 21.6072 - Extending the duration of a vocational training program.  

...Extending the duration of a vocational training program. 21.6072 Section...EDUCATION Temporary Program of Vocational Training for Certain New Pension Recipients...Extending the duration of a vocational training program. (a)...

2014-07-01

434

38 CFR 21.6070 - Basic duration of a vocational training program.  

...false Basic duration of a vocational training program. 21.6070 Section...EDUCATION Temporary Program of Vocational Training for Certain New Pension Recipients...6070 Basic duration of a vocational training program. (a) Basic...

2014-07-01

435

38 CFR 21.8070 - Basic duration of a vocational training program.  

...false Basic duration of a vocational training program. 21.8070 Section...REHABILITATION AND EDUCATION Vocational Training and Rehabilitation for Certain...Birth Defects Duration of Vocational Training § 21.8070 Basic...

2014-07-01

436

13 CFR 107.835 - Exceptions to minimum duration/term of Financing.  

Code of Federal Regulations, 2013 CFR

...false Exceptions to minimum duration/term of Financing. 107.835 Section 107...Financing of An Eligible Small Business: Terms and Conditions of Financing § 107.835 Exceptions to minimum duration/term of Financing. You may make a...

2013-01-01

437

13 CFR 107.830 - Minimum duration/term of financing.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Minimum duration/term of financing. 107.830 Section 107...Financing of An Eligible Small Business: Terms and Conditions of Financing § 107.830 Minimum duration/term of financing. (a) General rule....

2011-01-01

438

13 CFR 107.835 - Exceptions to minimum duration/term of Financing.  

Code of Federal Regulations, 2011 CFR

...false Exceptions to minimum duration/term of Financing. 107.835 Section 107...Financing of An Eligible Small Business: Terms and Conditions of Financing § 107.835 Exceptions to minimum duration/term of Financing. You may make a...

2011-01-01

439

13 CFR 107.830 - Minimum duration/term of financing.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Minimum duration/term of financing. 107.830 Section 107...Financing of An Eligible Small Business: Terms and Conditions of Financing § 107.830 Minimum duration/term of financing. (a) General rule....

2013-01-01

440

13 CFR 107.835 - Exceptions to minimum duration/term of Financing.  

Code of Federal Regulations, 2010 CFR

...false Exceptions to minimum duration/term of Financing. 107.835 Section 107...Financing of An Eligible Small Business: Terms and Conditions of Financing § 107.835 Exceptions to minimum duration/term of Financing. You may make a...

2010-01-01

441

13 CFR 107.830 - Minimum duration/term of financing.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Minimum duration/term of financing. 107.830 Section 107...Financing of An Eligible Small Business: Terms and Conditions of Financing § 107.830 Minimum duration/term of financing. (a) General rule....

2010-01-01

442

13 CFR 107.835 - Exceptions to minimum duration/term of Financing.  

Code of Federal Regulations, 2012 CFR

...false Exceptions to minimum duration/term of Financing. 107.835 Section 107...Financing of An Eligible Small Business: Terms and Conditions of Financing § 107.835 Exceptions to minimum duration/term of Financing. You may make a...

2012-01-01

443

13 CFR 107.835 - Exceptions to minimum duration/term of Financing.  

...false Exceptions to minimum duration/term of Financing. 107.835 Section 107...Financing of An Eligible Small Business: Terms and Conditions of Financing § 107.835 Exceptions to minimum duration/term of Financing. You may make a...

2014-01-01

444

13 CFR 107.830 - Minimum duration/term of financing.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Minimum duration/term of financing. 107.830 Section 107...Financing of An Eligible Small Business: Terms and Conditions of Financing § 107.830 Minimum duration/term of financing. (a) General rule....

2012-01-01

445

13 CFR 107.830 - Minimum duration/term of financing.  

...2014-01-01 false Minimum duration/term of financing. 107.830 Section 107...Financing of An Eligible Small Business: Terms and Conditions of Financing § 107.830 Minimum duration/term of financing. (a) General rule....

2014-01-01

446

15 CFR 784.4 - Notification, duration and frequency of complementary access.  

...2014-01-01 2014-01-01 false Notification, duration and frequency of complementary access. 784.4 Section 784.4 Commerce...COMPLEMENTARY ACCESS § 784.4 Notification, duration and frequency of complementary access. (a) Complementary access...

2014-01-01

447

42 CFR 457.65 - Effective date and duration of State plans and plan amendments.  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 false Effective date and duration of State...Insurance Programs and Outreach Strategies § 457.65 Effective date and duration of State...plan amendments. (a) Effective date in general....

2010-10-01

448

Model of medical supply demand and astronaut health for long-duration human space flight  

E-print Network

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 ...

Assad, Albert

2009-01-01

449

Magnetospheric application of high-altitude long-duration balloon technology: Daylight auroral observations  

E-print Network

Magnetospheric application of high-altitude long-duration balloon technology: Daylight auroral-altitude long-duration balloon technology. This paper dis- cusses the theoretical background of this application: Aurora; Auroral observations; Balloon technology; Magnetospheric application 1. Introduction Application

Lummerzheim, Dirk

450

38 CFR 21.6072 - Extending the duration of a vocational training program.  

Code of Federal Regulations, 2011 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...

2011-07-01

451

38 CFR 21.6072 - Extending the duration of a vocational training program.  

Code of Federal Regulations, 2012 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...

2012-07-01

452

38 CFR 21.6072 - Extending the duration of a vocational training program.  

Code of Federal Regulations, 2013 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...

2013-07-01

453

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...

2010-07-01

454

Influence of Rhythmic Grouping on Duration Perception: A Novel Auditory Illusion  

E-print Network

This study investigated a potential auditory illusion in duration perception induced by rhythmic temporal contexts. Listeners with or without musical training performed a duration discrimination task for a silent period ...

Geiser, Eveline

455

Developing a Habitat for Long Duration, Deep Space Missions  

NASA Technical Reports Server (NTRS)

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 cu m (9,464 cu ft) 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.

Rucker, Michelle A.; Thompson, Shelby

2012-01-01

456

Cardiovascular autonomic control after short-duration spaceflights  

NASA Astrophysics Data System (ADS)

After spaceflight, astronauts sometimes suffer a variable degree of reduced orthostatic tolerance. Although many studies have addressed this problem, many aspects remain unclear. Also, it is unknown how long the cardiovascular system needs to recover from short duration spaceflights. The scope of the present study was to determine a long-term follow-up of cardiovascular control up to 25 days after spaceflight under control conditions in five astronauts using heart rate variability, blood pressure variability and baroreflex sensitivity (BRS) indices. In standing position heart rate after spaceflight was significantly higher compared with pre-flight (R+1: 99 (SD 9) BPM vs L-30: 77 (SD 3) BPM; p<0.001). At the same time high frequency modulation of heart rate was extremely depressed (R+1: 70 (SD 334) ms 2 vs L-30: 271 (SD 68) ms 2; p<0.01), as was BRS: (R+1: 5 (SD 1) vs L-30: 10 (SD 2) ms/mmHg, p<0.05). These changes had largely recovered after 4 days upon return to Earth. Orthostatic blood pressure control was well maintained from the first day after landing. The decrease in BRS and in vagal heart rate modulation following short-duration spaceflight appear to constitute an adequate autonomic neural response to restored gravity. After 4 days upon return to Earth, vagal heart rate modulation is almost completely recovered to the pre-flight level. The findings of the present study demonstrate that the decrease in vagal heart rate modulation in standing position should not be characterised as some kind of cardiovascular deconditioning, but rather as the normal response to orthostatic stress after spaceflight.

Beckers, Frank; Verheyden, Bart; Liu, Jiexin; Aubert, André E.

2009-09-01

457

Factors Impacting Habitable Volume Requirements for Long Duration Missions  

NASA Technical Reports Server (NTRS)

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.

Simon, Matthew; Neubek, Deborah; Whitmire, Alexandria

2012-01-01

458

Developing a Habitat for Long Duration, Deep Space Missions  

NASA Technical Reports Server (NTRS)

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.

Rucker, Michelle A.; Thompson, Shelby

2011-01-01

459

Timing and Duration of Obesity in Relation to Diabetes  

PubMed Central

OBJECTIVE The influence on diabetes of the timing and duration of obesity across the high-risk period of adolescence to young adulthood has not been investigated in a population-based, ethnically diverse sample. RESEARCH DESIGN AND METHODS A cohort of 10,481 individuals aged 12–21 years enrolled in the U.S. National Longitudinal Study of Adolescent Health (1996) was followed over two visits during young adulthood (18–27 years, 2001–2002; 24–33 years, 2007–2009). Separate logistic regression models were used to examine the associations of diabetes (A1C ?6.5% or diagnosis by a health care provider) in young adulthood with 1) obesity timing (never obese, onset <16 years, onset 16 to <18 years, onset ?18 years) and 2) obesity duration over time (never obese, incident obesity, fluctuating obesity, and persistent obesity), testing differences by sex and race/ethnicity. RESULTS Among 24- to 33-year-old participants, 4.4% had diabetes (approximately half were undiagnosed), with a higher prevalence in blacks and Hispanics than whites. In multivariable analyses, women who became obese before age 16 were more likely to have diabetes than women who became obese at or after age 18 (odds ratio 2.77 [95% CI 1.39–5.52]), even after accounting for current BMI, waist circumference, and age at menarche. Persistent (vs. adult onset) obesity was associated with increased likelihood of diabetes in men (2.27 [1.41–3.64]) and women (2.08 [1.34–3.24]). CONCLUSIONS Diabetes risk is particularly high in individuals who were obese as adolescents relative to those with adult-onset obesity, thus highlighting the need for diabetes prevention efforts to address pediatric obesity. PMID:23223352

The, Natalie S.; Richardson, Andrea S.; Gordon-Larsen, Penny

2013-01-01

460

Does Treatment Duration Affect Outcome After Radiotherapy for Prostate Cancer?  

SciTech Connect

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.

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: mark.buyyounouski@fccc.edu

2008-12-01

461

Hedging interest rate risk with strip and rollover, and duration hedging strategies  

E-print Network

ANALYSIS OF DURATION BASED FINANCIAL HEDGING STRATEGIES 39 Introduction/Previous Research 39 CHAPTER PAGE Conceptual Framework . 41 Method of Measure Duration Based Hedging Duration and Spread Hedging Hedging Effectiveness 42 . 44 . 46 54 Model... For the Duration and Spread Hedging strategy For a Five Year, Fixed Loan Initiated June 1977. . . 59 Summary of Unhedged Positions For Twenty Four, Five Year, Fixed Rate Loans 61 Summary of Hedged Loan Profit and the Respective Hedge Margins foe Twenty Four...

Thompson, William J.

2012-06-07

462

Regulation of signal duration and the statistical dynamics of kinase activation by scaffold proteins  

E-print Network

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.

Jason W. Locasale; Arup K. Chakraborty

2008-07-13

463

Adults’ Perceptions of Experimental Modifications of Durations of Pauses and Expiratory Sounds in Infant Crying  

Microsoft Academic Search

Durations of all pauses and expiratory sounds in a 10-s bout of infant crying were digitally increased and decreased by 50% to create cries that varied in the duration of pauses and expiratory sounds. Ratings by 40 men and women showed a general monotonic effect of pause duration so that cries with increasingly shorter pauses were perceived to be more

Philip Sanford Zeskind; Laura Klein; Timothy R. Marshall

1992-01-01

464

Plasticity of the duration of metamorphosis in the African clawed toad  

E-print Network

Plasticity of the duration of metamorphosis in the African clawed toad P. T. Walsh, J. R. Downie, such as amphibians, selection is thought to have minimized the duration of metamorphosis, because this is the stage risk associated with prolonging metamorphosis is presumed to have selected for a duration as short

Gray, Matthew

465

A neural hierarchy for illusions of time: Duration adaptation precedes multisensory integration  

PubMed Central

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

Heron, James; Hotchkiss, John; Aaen-Stockdale, Craig; Roach, Neil W.; Whitaker, David

2013-01-01

466

Using phoneme duration and energy contour information to improve large vocabulary isolated-word recognition  

Microsoft Academic Search

Minimum duration constraints and energy thresholds for phonemes were used to increase the recognition accuracy of an 86000-word speaker-trained isolated word recognizer. Minimum duration constraints force the phoneme models to map to acoustic segments longer than the duration minima for the phonemes. Such constraints result in significant lowering of likelihoods of many incorrect word choices, improving the accuracy of acoustic

V. N. Gupta; M. Lennig; P. Mermelstein; P. Kenny; F. Seitz; D. O'Shaughnessy

1991-01-01

467

The Duration of Trade Revisited. Continuous-Time vs. Discrete-Time Hazards  

Microsoft Academic Search

The recent literature on the duration of trade has predominantly analyzed the determinants of trade flow durations using Cox proportional hazards models. The purpose of this paper is to show why it is inappropriate to analyze the duration of trade with continuous-time models such as the Cox model, and to propose alternative discrete-time models which are more suitable for estimation.

Wolfgang Hess; Maria Persson

2010-01-01

468

The Duration of Trade Revisited: Continuous-Time vs. Discrete-Time Hazards  

Microsoft Academic Search

The recent literature on the duration of trade has predominantly analyzed the determinants of trade flow durations using Cox proportional hazards models. The purpose of this paper is to show why it is inappropriate to analyze the duration of trade with continuous-time models such as the Cox model, and to propose alternative discrete-time models which are more suitable for estimation.

Wolfgang Hess; Maria Persson

2010-01-01

469

Camouflage mismatch in seasonal coat color due to decreased snow duration.  

PubMed

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 r