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Sample records for rat-psychomotor vigilance task

  1. Sleep Deprivation and Time-on-Task Performance Decrement in the Rat Psychomotor Vigilance Task

    PubMed Central

    Oonk, Marcella; Davis, Christopher J.; Krueger, James M.; Wisor, Jonathan P.; Van Dongen, Hans P.A.

    2015-01-01

    Study Objectives: The rat psychomotor vigilance task (rPVT) was developed as a rodent analog of the human psychomotor vigilance task (hPVT). We examined whether rPVT performance displays time-on-task effects similar to those observed on the hPVT. Design: The rPVT requires rats to respond to a randomly presented light stimulus to obtain a water reward. Rats were water deprived for 22 h prior to each 30-min rPVT session to motivate performance. We analyzed rPVT performance over time on task and as a function of the response-stimulus interval, at baseline and after sleep deprivation. Setting: The study was conducted in an academic research vivarium. Participants: Male Long-Evans rats were trained to respond to a 0.5 sec stimulus light within 3 sec of stimulus onset. Complete data were available for n = 20 rats. Interventions: Rats performed the rPVT for 30 min at baseline and after 24 h total sleep deprivation by gentle handling. Measurements and Results: Compared to baseline, sleep deprived rats displayed increased performance lapses and premature responses, similar to hPVT lapses of attention and false starts. However, in contrast to hPVT performance, the time-on-task performance decrement was not significantly enhanced by sleep deprivation. Moreover, following sleep deprivation, rPVT response times were not consistently increased after short response-stimulus intervals. Conclusions: The rat psychomotor vigilance task manifests similarities to the human psychomotor vigilance task in global performance outcomes, but not in post-sleep deprivation effects of time on task and response-stimulus interval. Citation: Oonk M, Davis CJ, Krueger JM, Wisor JP, Van Dongen HPA. Sleep deprivation and time-on-task performance decrement in the rat psychomotor vigilance task. SLEEP 2015;38(3):445–451. PMID:25515099

  2. Biocybernetic Control of Vigilance Task Parameters

    NASA Technical Reports Server (NTRS)

    Freeman, Frederick G.

    2000-01-01

    The major focus of the present proposal was to examine psychophysiological variables that are related to hazardous states of awareness induced by monitoring automated systems. With the increased use of automation in today's work environment, people's roles in the work place are being redefined from that of active participant to one of passive monitor. Although the introduction of automated systems has a number of benefits, there are also a number of disadvantages regarding the worker performance. Byrne and Parasuraman (1996) have argued for the use of psychophysiological measures in both the development and the implementation of adaptive automation. While both performance based and model based adaptive automation have been studied, the use of psychophysiological measures, especially EEG, offers the advantage of real time evaluation of the state of the subject. Previous investigations of the closed-loop adaptive automation system in our laboratory, supported by NASA, have employed a compensatory tracking task which involved the use of a joystick to maintain the position of a cursor in the middle of a video screen. This research demonstrated that, in an adaptive automation, closed-loop environment, subjects perform a tracking task better under a negative, compared to a positive, feedback condition. While tracking is comparable to some aspects of flying an airplane, it does not simulate the environment found in the cockpit of modern commercial airplanes. Since a large part of the flying responsibilities in commercial airplanes is automated, the primary responsibility of pilots is to monitor the automation and to respond when the automation fails. Because failures are relatively rare, pilots often suffer from hazardous states of awareness induced by long term vigilance of the automated system. Consequently, the aim of the current study was to investigate the ability of the closed-loop, adaptive automation system in a vigilance paradigm. It is also important to note

  3. Physiological Synchronization in a Vigilance Dual Task.

    PubMed

    Guastello, Stephen J

    2016-01-01

    The synchronization of autonomic arousal levels and other physio-logical responses between people is a potentially important component of work team performance, client-therapist relationships, and other types of human interaction. This study addressed several problems: What statistical models are viable for identifying synchronization for loosely coupled human systems? How is the level of synchronization related to psychosocial variables such as empathy, subjective ratings of workload, and actual performance? Participants were 70 undergraduates who worked in pairs on a vigilance dual task in which they watched a virtual reality security camera, rang a bell when they saw the target intruder, and completed a jig-saw puzzle. Event rates either increased or decreased during the 90 min work period. The average R2 values for each person were .66, .66, .62, and .53 for the linear autoregressive model, linear autoregressive model with a synchronization component, the nonlinear autoregressive model, and the nonlinear autoregressive model with a synchronization component, respectively. All models were more accurate at a lag of 20 sec compared to 50 sec or customized lag lengths. Although the linear models were more accurate overall, the nonlinear synchronization parameters were more often related to psychological variables and performance. In particular, greater synchronization was observed with the nonlinear model when the target event rate increased, compared to when it decreased, which was expected from the general theory of synchronization. Nonlinear models were also more effective for uncovering inhibitory or dampening relationships between the co-workers as well as mutually excitatory relationships. Future research should explore the comparative model results for tasks that induce higher levels of synchronization and involve different types of internal group coordination.

  4. Influence of gender on psychomotor vigilance task performance by adolescents.

    PubMed

    Beijamini, F; Silva, A G T; Peixoto, C A T; Louzada, F M

    2008-08-01

    During adolescence, the sleep phase delay associated with early school times increases daytime sleepiness and reduces psychomotor performance. Some studies have shown an effect of gender on psychomotor performance in adults and children. Males present faster reaction times (RT) compared with females. The aim of the present study was to evaluate the influence of gender on Palm psychomotor vigilance task (PVT) performance in adolescents. Thirty-four adolescents (19 girls, 13 to 16 years old) attending morning school classes of a public school in Curitiba, PR, Brazil, participated in the study. Sleep patterns were measured using actigraphy and sleepiness data were accessed with the Karolinska Sleepiness Scale (KSS). KSS and PVT measurements were collected at two times in the morning (8:00 and 11:00 h). The data were compared using one-way ANOVA, considering gender as a factor. ANOVA indicated that gender did not affect sleep patterns and subjective somnolence; however, a statistically significant effect of gender was detected for PVT performance. Boys presented faster RT (RT-PVT1: 345.51 ms, F = 6.08, P < 0.05; RT-PVT2: 343.30 ms, F = 6.35, P < 0.05) and fewer lapses (lapses-PVT1: 8.71, F = 4.45, P < 0.05; lapses-PVT2: 7.82, F = 7.06, P < 0.05) compared with girls (RT-PVT1: 402.96; RT-PVT2: 415.70; lapses-PVT1: 16.33; lapses-PVT2: 17.80). These results showed that this effect of gender, already reported in adults and children, is also observed in adolescents. The influence of gender should be taken into account in studies that use Palm PVT to evaluate psychomotor performance in this age range. PMID:18797710

  5. Influence of gender on psychomotor vigilance task performance by adolescents.

    PubMed

    Beijamini, F; Silva, A G T; Peixoto, C A T; Louzada, F M

    2008-08-01

    During adolescence, the sleep phase delay associated with early school times increases daytime sleepiness and reduces psychomotor performance. Some studies have shown an effect of gender on psychomotor performance in adults and children. Males present faster reaction times (RT) compared with females. The aim of the present study was to evaluate the influence of gender on Palm psychomotor vigilance task (PVT) performance in adolescents. Thirty-four adolescents (19 girls, 13 to 16 years old) attending morning school classes of a public school in Curitiba, PR, Brazil, participated in the study. Sleep patterns were measured using actigraphy and sleepiness data were accessed with the Karolinska Sleepiness Scale (KSS). KSS and PVT measurements were collected at two times in the morning (8:00 and 11:00 h). The data were compared using one-way ANOVA, considering gender as a factor. ANOVA indicated that gender did not affect sleep patterns and subjective somnolence; however, a statistically significant effect of gender was detected for PVT performance. Boys presented faster RT (RT-PVT1: 345.51 ms, F = 6.08, P < 0.05; RT-PVT2: 343.30 ms, F = 6.35, P < 0.05) and fewer lapses (lapses-PVT1: 8.71, F = 4.45, P < 0.05; lapses-PVT2: 7.82, F = 7.06, P < 0.05) compared with girls (RT-PVT1: 402.96; RT-PVT2: 415.70; lapses-PVT1: 16.33; lapses-PVT2: 17.80). These results showed that this effect of gender, already reported in adults and children, is also observed in adolescents. The influence of gender should be taken into account in studies that use Palm PVT to evaluate psychomotor performance in this age range.

  6. Brief and Rare Mental "Breaks" Keep You Focused: Deactivation and Reactivation of Task Goals Preempt Vigilance Decrements

    ERIC Educational Resources Information Center

    Ariga, Atsunori; Lleras, Alejandro

    2011-01-01

    We newly propose that the vigilance decrement occurs because the cognitive control system fails to maintain active the goal of the vigilance task over prolonged periods of time (goal habituation). Further, we hypothesized that momentarily deactivating this goal (via a switch in tasks) would prevent the activation level of the vigilance goal from…

  7. Vigilance impossible: Diligence, distraction, and daydreaming all lead to failures in a practical monitoring task.

    PubMed

    Casner, Stephen M; Schooler, Jonathan W

    2015-09-01

    In laboratory studies of vigilance, participants watch for unusual events in a "sit and stare" fashion as their performance typically declines over time. But watch keepers in practical settings seldom approach monitoring in such simplistic ways and controlled environments. We observed airline pilots performing routine monitoring duties in the cockpit. Unlike laboratory studies, pilots' monitoring did not deteriorate amidst prolonged vigils. Monitoring was frequently interrupted by other pop-up tasks and misses followed. However, when free from these distractions, pilots reported copious mind wandering. Pilots often confined their mind wandering to times in which their monitoring performance would not conspicuously suffer. But when no convenient times were available, pilots mind wandered anyway and misses ensued. Real-world monitors may be caught between a continuous vigilance approach that is doomed to fail, a dynamic environment that cannot be fully controlled, and what may be an irresistible urge to let one's thoughts drift.

  8. Vigilance impossible: Diligence, distraction, and daydreaming all lead to failures in a practical monitoring task.

    PubMed

    Casner, Stephen M; Schooler, Jonathan W

    2015-09-01

    In laboratory studies of vigilance, participants watch for unusual events in a "sit and stare" fashion as their performance typically declines over time. But watch keepers in practical settings seldom approach monitoring in such simplistic ways and controlled environments. We observed airline pilots performing routine monitoring duties in the cockpit. Unlike laboratory studies, pilots' monitoring did not deteriorate amidst prolonged vigils. Monitoring was frequently interrupted by other pop-up tasks and misses followed. However, when free from these distractions, pilots reported copious mind wandering. Pilots often confined their mind wandering to times in which their monitoring performance would not conspicuously suffer. But when no convenient times were available, pilots mind wandered anyway and misses ensued. Real-world monitors may be caught between a continuous vigilance approach that is doomed to fail, a dynamic environment that cannot be fully controlled, and what may be an irresistible urge to let one's thoughts drift. PMID:25966369

  9. Vigilance and task load - In search of the inverted U

    NASA Technical Reports Server (NTRS)

    Wiener, E. L.; Curry, R. E.; Faustina, M. L.

    1984-01-01

    The 'Inverted-U Hypothesis' states that for a given task, there is an optimal level of workload or demand that yields the highest level of performance. A departure in either direction will result in a monotonically lower performance level, hence an inverted-U-shaped relationship between task demand and quality of performance. Most studies to date have failed to demonstrate the left-hand branch of the curve, that is, the regime in which performance presumably rises as load increases. The purpose of this study was to explore whether low-level additional demand on the monitor would result in improved performance. Four groups of subjects performed a visual monitoring task for 48 min, then two of the four groups were given additional tasks, and a third had potentially distracting information on its display. Results indicated that the two groups with additional demand detected more signals than did the control group or the control-plus-distraction group. There were no significant differences in false alarms.

  10. The electrocortical correlates of fluctuating states of attention during vigilance tasks

    NASA Technical Reports Server (NTRS)

    Cunningham, Stephen G.; Freeman, Frederick

    1994-01-01

    This study investigated the electrocortical correlates of attention. Sixteen subjects (seven females, nine males) engaged in a forty-minute target detection vigilance task. Task-irrelevant probe tones were presented every 2-4 seconds. While performing the vigilance task, the subjects were asked to press a button if they were daydreaming (i.e. having a task unrelated thought or TUT). Continuous electroencephalograms (EEG's) and event-related potentials (ERP's) were recorded from the subjects during the entire task. The continuous EEG data were analyzed for differences in absolute power throughout the task as well as before and after the subjects indicated that they were daydreaming (TUT response). ERP's elicited by task-irrelevant probe tones were analyzed in the same manner. The results indicated performance decrements as reflected by increased RT to correct detections, and decreased number of hits. Further, as the task progressed, the number of reports of daydreaming increased. The analysis of the EEG data indicated a significant difference in the absolute power of the different frequency bands across periods. The greatest difference was observed at the posterior parietal electrode sites. In addition, when the EEG data was converted into band ratios (beta/alpha and beta/alpha+theta), the pre-TUT conditions were found to be significantly different than the post-TUT conditions in the posterior sites. The ERP components (N1, N2, and P2) were not significantly different before and after a TUT response or across periods. However, the ERP's across periods exhibited amplitudes that were similar to those found in previous studies of vigilance and ERP's.

  11. Psychomotor Vigilance Task Performance During and Following Chronic Sleep Restriction in Rats

    PubMed Central

    Deurveilher, Samuel; Bush, Jacquelyn E.; Rusak, Benjamin; Eskes, Gail A.; Semba, Kazue

    2015-01-01

    Study Objectives: Chronic sleep restriction (CSR) impairs sustained attention in humans, as commonly assessed with the psychomotor vigilance task (PVT). To further investigate the mechanisms underlying performance deficits during CSR, we examined the effect of CSR on performance on a rat version of PVT (rPVT). Design: Adult male rats were trained on a rPVT that required them to press a bar when they detected irregularly presented, brief light stimuli, and were then tested during CSR. CSR consisted of 100 or 148 h of continuous cycles of 3-h sleep deprivation (using slowly rotating wheels) alternating with a 1-h sleep opportunity (3/1 protocol). Measurements and Results: After 28 h of CSR, the latency of correct responses and the percentages of lapses and omissions increased, whereas the percentage of correct responses decreased. Over 52–148 h of CSR, all performance measures showed partial or nearly complete recovery, and were at baseline levels on the first or second day after CSR. There were large interindividual differences in the magnitude of performance impairment during CSR, suggesting differential vulnerability to the effects of sleep loss. Wheel-running controls showed no changes in performance. Conclusions: A 28-h period of the 3/1 chronic sleep restriction (CSR) protocol disrupted performance on a sustained attention task in rats, as sleep deprivation does in humans. Performance improved after longer periods of CSR, suggesting allostatic adaptation, contrary to some reports of progressive deterioration in psychomotor vigilance task performance during CSR in humans. However, as observed in humans, there were individual differences among rats in the vulnerability of their attention performance to CSR. Citation: Deurveilher S, Bush JE, Rusak B, Eskes GA, Semba K. Psychomotor vigilance task performance during and following chronic sleep restriction in rats. SLEEP 2015;38(4):515–528. PMID:25515100

  12. Investigating the correlation between the neural activity and task performance in a psychomotor vigilance test.

    PubMed

    Hu, Zhongze; Sun, Yu; Lim, Julian; Thakor, Nitish; Bezerianos, Anastasios

    2015-01-01

    Neural activity is known to correlate with decrements in task performance as individuals enter the state of mental fatigue which might lead to lowered productivity and increased safety risks. Incorporating a passive brain computer interface (BCI) technique that detects changes in subject's neural activity and predicts the behavioral performance when the subject is underperforming might be a promising approach to reduce human error in real-world situations. Here, we developed a reliable model using EEG power spectrum to estimate time-on-task performance in a psychomotor vigilance test (PVT) which can fit across individuals. High correlation between the estimated and actual reaction time was achieved. Hence, our results illustrate the feasibility for modeling time-on-task decrements in performance among different individuals from their brainwave activity, with potential applications in several domains, including traffic and industrial safety. PMID:26737349

  13. Reliability of the 5-min psychomotor vigilance task in a primary school classroom setting.

    PubMed

    Wilson, Andrew; Dollman, James; Lushington, Kurt; Olds, Timothy

    2010-08-01

    This study evaluated the reliability of the 5-min psychomotor vigilance task (PVT) in a single-sex Australian primary school. Seventy-five male students (mean age = 11.82 years, SD = 1.12) completed two 5-min PVTs using a Palm personal digital assistant (PDA) in (1) an isolated setting and (2) a classroom setting. Of this group of students, a subsample of 37 students completed a test-retest reliability trial within the classroom setting. Using a mixed-model analysis, there was no significant difference in the mean response time (RT) or number of lapses (RTs >or= 500 msec) between the isolated and the classroom setting. There was, however, an order effect for the number of lapses in the isolated setting, with the number of lapses being greater if the isolated test was conducted second. Test-retest intraclass correlation coefficients (ICCs) in the classroom setting indicated moderate to high reliability (mean RT = .84, lapses = .59). Bland-Altman analysis showed no systematic difference between the two settings. Findings suggest that the 5-min PDA PVT is a reliable measure of sustained attention in the classroom setting in this sample of primary-aged schoolchildren. The results provide further evidence for the versatility of this measuring device for larger interventions outside the laboratory. PMID:20805597

  14. Reliability of the 5-min psychomotor vigilance task in a primary school classroom setting.

    PubMed

    Wilson, Andrew; Dollman, James; Lushington, Kurt; Olds, Timothy

    2010-08-01

    This study evaluated the reliability of the 5-min psychomotor vigilance task (PVT) in a single-sex Australian primary school. Seventy-five male students (mean age = 11.82 years, SD = 1.12) completed two 5-min PVTs using a Palm personal digital assistant (PDA) in (1) an isolated setting and (2) a classroom setting. Of this group of students, a subsample of 37 students completed a test-retest reliability trial within the classroom setting. Using a mixed-model analysis, there was no significant difference in the mean response time (RT) or number of lapses (RTs >or= 500 msec) between the isolated and the classroom setting. There was, however, an order effect for the number of lapses in the isolated setting, with the number of lapses being greater if the isolated test was conducted second. Test-retest intraclass correlation coefficients (ICCs) in the classroom setting indicated moderate to high reliability (mean RT = .84, lapses = .59). Bland-Altman analysis showed no systematic difference between the two settings. Findings suggest that the 5-min PDA PVT is a reliable measure of sustained attention in the classroom setting in this sample of primary-aged schoolchildren. The results provide further evidence for the versatility of this measuring device for larger interventions outside the laboratory.

  15. Sustaining Attention to Simple Tasks: A Meta-Analytic Review of the Neural Mechanisms of Vigilant Attention

    PubMed Central

    Langner, Robert; Eickhoff, Simon B.

    2012-01-01

    Maintaining attention for more than a few seconds is essential for mastering everyday life. Yet, our ability to stay focused on a particular task is limited, resulting in well-known performance decrements with increasing time on task. Intriguingly, such decrements are even more likely if the task is cognitively simple and repetitive. The attentional function that enables our prolonged engagement in intellectually unchallenging, uninteresting activities has been termed “vigilant attention.” Here we synthesized what we have learnt from functional neuroimaging about the mechanisms of this essential mental faculty. To this end, a quantitative meta-analysis of pertinent neuroimaging studies was performed, including supplementary analyses of moderating factors. Furthermore, we reviewed the available evidence on neural time-on-task effects, additionally considering information obtained from patients with focal brain damage. Integrating the results of both meta-analysis and review, a set of mainly right-lateralized brain regions was identified that may form the core network subserving vigilant attention in humans, including dorsomedial, mid- and ventrolateral prefrontal cortex, anterior insula, parietal areas (intraparietal sulcus, temporo-parietal junction), and subcortical structures (cerebellar vermis, thalamus, putamen, midbrain). We discuss the potential functional roles of different nodes of this network as well as implications of our findings for a theoretical account of vigilant attention. It is conjectured that sustaining attention is a multi-component, non-unitary mental faculty, involving a mixture of (i) sustained/recurrent processes subserving task-set/arousal maintenance and (ii) transient processes subserving the target-driven reorienting of attention. Finally, limitations of previous studies are considered and suggestions for future research are provided. PMID:23163491

  16. Time-on-task decrement in vigilance is modulated by inter-individual vulnerability to homeostatic sleep pressure manipulation.

    PubMed

    Maire, Micheline; Reichert, Carolin F; Gabel, Virginie; Viola, Antoine U; Krebs, Julia; Strobel, Werner; Landolt, Hans-Peter; Bachmann, Valérie; Cajochen, Christian; Schmidt, Christina

    2014-01-01

    Under sleep loss, vigilance is reduced and attentional failures emerge progressively. It becomes difficult to maintain stable performance over time, leading to growing performance variability (i.e., state instability) in an individual and among subjects. Task duration plays a major role in the maintenance of stable vigilance levels, such that the longer the task, the more likely state instability will be observed. Vulnerability to sleep-loss-dependent performance decrements is highly individual and is also modulated by a polymorphism in the human clock gene PERIOD3 (PER3). By combining two different protocols, we manipulated sleep-wake history by once extending wakefulness for 40 h (high sleep pressure condition) and once by imposing a short sleep-wake cycle by alternating 160 min of wakefulness and 80 min naps (low sleep pressure condition) in a within-subject design. We observed that homozygous carriers of the long repeat allele of PER3 (PER3 (5/5) ) experienced a greater time-on-task dependent performance decrement (i.e., a steeper increase in the number of lapses) in the Psychomotor Vigilance Task compared to the carriers of the short repeat allele (PER3 (4/4) ). These genotype-dependent effects disappeared under low sleep pressure conditions, and neither motivation, nor perceived effort accounted for these differences. Our data thus suggest that greater sleep-loss related attentional vulnerability based on the PER3 polymorphism is mirrored by a greater state instability under extended wakefulness in the short compared to the long allele carriers. Our results undermine the importance of time-on-task related aspects when investigating inter-individual differences in sleep loss-induced behavioral vulnerability.

  17. Time-on-task decrement in vigilance is modulated by inter-individual vulnerability to homeostatic sleep pressure manipulation

    PubMed Central

    Maire, Micheline; Reichert, Carolin F.; Gabel, Virginie; Viola, Antoine U.; Krebs, Julia; Strobel, Werner; Landolt, Hans-Peter; Bachmann, Valérie; Cajochen, Christian; Schmidt, Christina

    2014-01-01

    Under sleep loss, vigilance is reduced and attentional failures emerge progressively. It becomes difficult to maintain stable performance over time, leading to growing performance variability (i.e., state instability) in an individual and among subjects. Task duration plays a major role in the maintenance of stable vigilance levels, such that the longer the task, the more likely state instability will be observed. Vulnerability to sleep-loss-dependent performance decrements is highly individual and is also modulated by a polymorphism in the human clock gene PERIOD3 (PER3). By combining two different protocols, we manipulated sleep-wake history by once extending wakefulness for 40 h (high sleep pressure condition) and once by imposing a short sleep-wake cycle by alternating 160 min of wakefulness and 80 min naps (low sleep pressure condition) in a within-subject design. We observed that homozygous carriers of the long repeat allele of PER3 (PER35/5) experienced a greater time-on-task dependent performance decrement (i.e., a steeper increase in the number of lapses) in the Psychomotor Vigilance Task compared to the carriers of the short repeat allele (PER34/4). These genotype-dependent effects disappeared under low sleep pressure conditions, and neither motivation, nor perceived effort accounted for these differences. Our data thus suggest that greater sleep-loss related attentional vulnerability based on the PER3 polymorphism is mirrored by a greater state instability under extended wakefulness in the short compared to the long allele carriers. Our results undermine the importance of time-on-task related aspects when investigating inter-individual differences in sleep loss-induced behavioral vulnerability. PMID:24639634

  18. On the Need of Objective Vigilance Monitoring: Effects of Sleep Loss on Target Detection and Task-Negative Activity Using Combined EEG/fMRI

    PubMed Central

    Czisch, Michael; Wehrle, Renate; Harsay, Helga A.; Wetter, Thomas C.; Holsboer, Florian; Sämann, Philipp G.; Drummond, Sean P. A.

    2012-01-01

    Sleep loss affects attention by reducing levels of arousal and alertness. The neural mechanisms underlying the compensatory efforts of the brain to maintain attention and performance after sleep deprivation (SD) are not fully understood. Previous neuroimaging studies of SD have not been able to separate the effects of reduced arousal from the effects of SD on cerebral responses to cognitive challenges. Here, we used a simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) approach to study the effects of 36 h of total sleep deprivation (TSD). Specifically, we focused on changes in selective attention processes as induced by an active acoustic oddball task, with the ability to isolate runs with objective EEG signs of high (SDalert) or reduced (SDsleepy) vigilance. In the SDalert condition, oddball task-related activity appears to be sustained by compensatory co-activation of insular regions, but task-negative activity in the right posterior node of the default mode network is altered following TSD. In the SDsleepy condition, oddball task-positive activity was massively impaired, but task-negative activation was showing levels comparable with the control condition after a well-rested night. Our results suggest that loss of strict negative correlation between oddball task-positive and task-negative activation reflects the effects of TSD, while the actual state of vigilance during task performance can affects either task-related or task-negative activity, depending on the exact vigilance level. PMID:22557992

  19. Vigilance Task-Related Change in Brain Functional Connectivity as Revealed by Wavelet Phase Coherence Analysis of Near-Infrared Spectroscopy Signals

    PubMed Central

    Wang, Wei; Wang, Bitian; Bu, Lingguo; Xu, Liwei; Li, Zengyong; Fan, Yubo

    2016-01-01

    This study aims to assess the vigilance task-related change in connectivity in healthy adults using wavelet phase coherence (WPCO) analysis of near-infrared spectroscopy signals (NIRS). NIRS is a non-invasive neuroimaging technique for assessing brain activity. Continuous recordings of the NIRS signals were obtained from the prefrontal cortex (PFC) and sensorimotor cortical areas of 20 young healthy adults (24.9 ± 3.3 years) during a 10-min resting state and a 20-min vigilance task state. The vigilance task was used to simulate driving mental load by judging three random numbers (i.e., whether odd numbers). The task was divided into two sessions: the first 10 min (Task t1) and the second 10 min (Task t2). The WPCO of six channel pairs were calculated in five frequency intervals: 0.6–2 Hz (I), 0.145–0.6 Hz (II), 0.052–0.145 Hz (III), 0.021–0.052 Hz (IV), and 0.0095–0.021 Hz (V). The significant WPCO formed global connectivity (GC) maps in intervals I and II and functional connectivity (FC) maps in intervals III to V. Results show that the GC levels in interval I and FC levels in interval III were significantly lower in the Task t2 than in the resting state (p < 0.05), particularly between the left PFC and bilateral sensorimotor regions. Also, the reaction time (RT) shows an increase in Task t2 compared with that in Task t1. However, no significant difference in WPCO was found between Task t1 and resting state. The results showed that the change in FC at the range of 0.6–2 Hz was not attributed to the vigilance task per se, but the interaction effect of vigilance task and time factors. The findings suggest that the decreased attention level might be partly attributed to the reduced GC levels between the left prefrontal region and sensorimotor area. The present results provide a new insight into the vigilance task-related brain activity. PMID:27547182

  20. Vigilance Task-Related Change in Brain Functional Connectivity as Revealed by Wavelet Phase Coherence Analysis of Near-Infrared Spectroscopy Signals.

    PubMed

    Wang, Wei; Wang, Bitian; Bu, Lingguo; Xu, Liwei; Li, Zengyong; Fan, Yubo

    2016-01-01

    This study aims to assess the vigilance task-related change in connectivity in healthy adults using wavelet phase coherence (WPCO) analysis of near-infrared spectroscopy signals (NIRS). NIRS is a non-invasive neuroimaging technique for assessing brain activity. Continuous recordings of the NIRS signals were obtained from the prefrontal cortex (PFC) and sensorimotor cortical areas of 20 young healthy adults (24.9 ± 3.3 years) during a 10-min resting state and a 20-min vigilance task state. The vigilance task was used to simulate driving mental load by judging three random numbers (i.e., whether odd numbers). The task was divided into two sessions: the first 10 min (Task t1) and the second 10 min (Task t2). The WPCO of six channel pairs were calculated in five frequency intervals: 0.6-2 Hz (I), 0.145-0.6 Hz (II), 0.052-0.145 Hz (III), 0.021-0.052 Hz (IV), and 0.0095-0.021 Hz (V). The significant WPCO formed global connectivity (GC) maps in intervals I and II and functional connectivity (FC) maps in intervals III to V. Results show that the GC levels in interval I and FC levels in interval III were significantly lower in the Task t2 than in the resting state (p < 0.05), particularly between the left PFC and bilateral sensorimotor regions. Also, the reaction time (RT) shows an increase in Task t2 compared with that in Task t1. However, no significant difference in WPCO was found between Task t1 and resting state. The results showed that the change in FC at the range of 0.6-2 Hz was not attributed to the vigilance task per se, but the interaction effect of vigilance task and time factors. The findings suggest that the decreased attention level might be partly attributed to the reduced GC levels between the left prefrontal region and sensorimotor area. The present results provide a new insight into the vigilance task-related brain activity. PMID:27547182

  1. Event-related cerebral hemodynamics reveal target-specific resource allocation for both "go" and "no-go" response-based vigilance tasks.

    PubMed

    Shaw, Tyler H; Funke, Matthew E; Dillard, Michael; Funke, Gregory J; Warm, Joel S; Parasuraman, Raja

    2013-08-01

    Transcranial Doppler sonography was used to measure cerebral blood flow velocity (CBFV) in the right and left cerebral hemispheres during the performance of a 50-min visual vigilance session. Observers monitored a simulated flight of unmanned aerial vehicles for cases in which one of the vehicles was flying in an inappropriate direction relative to its cohorts. Two types of vigilance tasks were employed: a traditional task in which observers made button press ("go") responses to critical signals, and a modification of the traditional task called the Sustained Attention to Response Task (SART) in which "go" responses acknowledged nonsignal events and response withholding ("no-go") signified signal detection. Signal detections and global CBFV scores declined over time. In addition, fine-grained event-related analyses revealed that the detection of signals was accompanied by an elevation of CBFV that was not present with missed signals. As was the case with the global scores, the magnitude of the transient CBFV increments associated with signal detection also declined over time, and these findings were independent of task type. The results support the view of CBFV as an index of the cognitive evaluation of stimulus significance, and a resource model of vigilance in which the need for continuous attention produces a depletion of information-processing assets that are not replenished as the task progresses. Further, temporal declines in the magnitude of event-related CBFV in response to critical signals only is evidence that the decrement function in vigilance is due to attentional processing and not specific task elements such as the required response format.

  2. Central additive effect of Ginkgo biloba and Rhodiola rosea on psychomotor vigilance task and short-term working memory accuracy

    PubMed Central

    Al-Kuraishy, Hayder M.

    2016-01-01

    Aim: The present study investigates the effect of combined treatment with Ginkgo biloba and/or Rhodiola rosea on psychomotor vigilance task (PVT) and short-term working memory accuracy. Subjects and Methods: A total number of 112 volunteers were enrolled to study the effect of G. biloba and R. rosea on PVT and short-term working memory accuracy as compared to placebo effects, the central cognitive effect was assessed by critical flicker-fusion frequency, PVT, and computerized N-back test. Results: Placebo produced no significant effects on all neurocognitive tests measure P > 0.05 in normal healthy volunteers, G. biloba or R. rosea improve PVT and low to moderate working memory accuracy, The combined effect of R. rosea and G. biloba leading to more significant effect on PVT, all levels of short-term working memory accuracy and critical fusion versus flicker P < 0.01, more than of G. biloba or R. rosea when they used alone. Conclusion: The combined effect of R. rosea and G. biloba leading to a more significant effect on cognitive function than either G. biloba or R. rosea when they used alone. PMID:27069717

  3. Bioelectric and microcirculation cutaneous sensors for the study of vigilance and emotional response during tasks and tests.

    PubMed

    Rada, H; Dittmar, A; Delhomme, G; Collet, C; Roure, R; Vernet-Maury, E; Priez, A

    1995-01-01

    Bioelectronic phenomena related to the activity of the Autonomic Nervous System (ANS) activity mainly take place in the deep part of the brain where they are difficult to record. The hand skin, being richly innervated by sympathetic efferent fibres, offers an interface from which relevant ANS-related signals can be recorded. Two non-invasive bioelectronic measurements (skin resistance and potential) reflecting the activity of the ANS were performed at the skin surface. These measurements were complemented by thermovascular (skin microcirculation and skin temperature) and cardiorespiratory (instantaneous heart rate and instantaneous respiratory frequency) measurements. The bioelectric measurements were performed using noninvasive Ag/AgCl electrodes. Non-metallic NASICON (Na Super Ionic Conductor) electrodes were tested and compared with traditional electrodes for the optimization of bioelectric measurements. Signal analysis and data processing was accomplished by means of original indices on a specially designed PC-based software. The methodology was used to evaluate vigilance level, mental workload, and emotional response during tasks (sporting activity, mental calculation, olfactive stimuli) and in critical situations (car crash avoidance). PMID:7734122

  4. In-flight sleep, pilot fatigue and Psychomotor Vigilance Task performance on ultra-long range versus long range flights.

    PubMed

    Gander, Philippa H; Signal, T Leigh; van den Berg, Margo J; Mulrine, Hannah M; Jay, Sarah M; Jim Mangie, Captain

    2013-12-01

    This study evaluated whether pilot fatigue was greater on ultra-long range (ULR) trips (flights >16 h on 10% of trips in a 90-day period) than on long range (LR) trips. The within-subjects design controlled for crew complement, pattern of in-flight breaks, flight direction and departure time. Thirty male Captains (mean age = 54.5 years) and 40 male First officers (mean age = 48.0 years) were monitored on commercial passenger flights (Boeing 777 aircraft). Sleep was monitored (actigraphy, duty/sleep diaries) from 3 days before the first study trip to 3 days after the second study trip. Karolinska Sleepiness Scale, Samn-Perelli fatigue ratings and a 5-min Psychomotor Vigilance Task were completed before, during and after every flight. Total sleep in the 24 h before outbound flights and before inbound flights after 2-day layovers was comparable for ULR and LR flights. All pilots slept on all flights. For each additional hour of flight time, they obtained an estimated additional 12.3 min of sleep. Estimated mean total sleep was longer on ULR flights (3 h 53 min) than LR flights (3 h 15 min; P(F) = 0.0004). Sleepiness ratings were lower and mean reaction speed was faster at the end of ULR flights. Findings suggest that additional in-flight sleep mitigated fatigue effectively on longer flights. Further research is needed to clarify the contributions to fatigue of in-flight sleep versus time awake at top of descent. The study design was limited to eastward outbound flights with two Captains and two First Officers. Caution must be exercised when extrapolating to different operations. PMID:23889686

  5. In-flight sleep, pilot fatigue and Psychomotor Vigilance Task performance on ultra-long range versus long range flights.

    PubMed

    Gander, Philippa H; Signal, T Leigh; van den Berg, Margo J; Mulrine, Hannah M; Jay, Sarah M; Jim Mangie, Captain

    2013-12-01

    This study evaluated whether pilot fatigue was greater on ultra-long range (ULR) trips (flights >16 h on 10% of trips in a 90-day period) than on long range (LR) trips. The within-subjects design controlled for crew complement, pattern of in-flight breaks, flight direction and departure time. Thirty male Captains (mean age = 54.5 years) and 40 male First officers (mean age = 48.0 years) were monitored on commercial passenger flights (Boeing 777 aircraft). Sleep was monitored (actigraphy, duty/sleep diaries) from 3 days before the first study trip to 3 days after the second study trip. Karolinska Sleepiness Scale, Samn-Perelli fatigue ratings and a 5-min Psychomotor Vigilance Task were completed before, during and after every flight. Total sleep in the 24 h before outbound flights and before inbound flights after 2-day layovers was comparable for ULR and LR flights. All pilots slept on all flights. For each additional hour of flight time, they obtained an estimated additional 12.3 min of sleep. Estimated mean total sleep was longer on ULR flights (3 h 53 min) than LR flights (3 h 15 min; P(F) = 0.0004). Sleepiness ratings were lower and mean reaction speed was faster at the end of ULR flights. Findings suggest that additional in-flight sleep mitigated fatigue effectively on longer flights. Further research is needed to clarify the contributions to fatigue of in-flight sleep versus time awake at top of descent. The study design was limited to eastward outbound flights with two Captains and two First Officers. Caution must be exercised when extrapolating to different operations.

  6. Cognitive Workload and Fatigue in a Vigilance Dual Task: Miss Errors, False Alarms, and the Effect of Wearing Biometric Sensors While Working.

    PubMed

    Guastello, Stephen J; Reiter, Katherine E; Malon, Matthew

    2016-10-01

    The effects of workload, fatigue, and practice on the performance of cognitive tasks are often intertwined. Previous research has shown that these influences can be separated with the two cusp catastrophe models. This study expanded an earlier investigation of the two models for workload and fatigue in a vigilance task to include a wider range of bifurcation variables that could affect the elasticity versus rigidity of the operator in response to workload and added performance variability resulting from fatigue. The study also responded to a concern in the literature that performance on cognitive tasks can be complicated by adaptive responses to artificial task situations and thus distort underlying cognitive events. Therefore, we also explored whether wearing biometric sensors, frequently used in workload studies, can affect performance dynamics. Participants were 279 undergraduates who responded to target stimuli that appeared on a simulated security camera display at three rates of speed while completing a secondary task. Participants worked alone, in pairs, or in pairs wearing GSR sensors. Results supported the efficacy of the two models and isolated the impact of wearing sensors on the fatigue process. The strongest control variables across both the workload and fatigue models were field independence, anxiety, indecisiveness, inflexibility, secondary task completion, working in pairs, and wearing the sensors. The contributing effect of wearing sensors could possibly extend to other types of wearable technologies. PMID:27550706

  7. Cognitive Workload and Fatigue in a Vigilance Dual Task: Miss Errors, False Alarms, and the Effect of Wearing Biometric Sensors While Working.

    PubMed

    Guastello, Stephen J; Reiter, Katherine E; Malon, Matthew

    2016-10-01

    The effects of workload, fatigue, and practice on the performance of cognitive tasks are often intertwined. Previous research has shown that these influences can be separated with the two cusp catastrophe models. This study expanded an earlier investigation of the two models for workload and fatigue in a vigilance task to include a wider range of bifurcation variables that could affect the elasticity versus rigidity of the operator in response to workload and added performance variability resulting from fatigue. The study also responded to a concern in the literature that performance on cognitive tasks can be complicated by adaptive responses to artificial task situations and thus distort underlying cognitive events. Therefore, we also explored whether wearing biometric sensors, frequently used in workload studies, can affect performance dynamics. Participants were 279 undergraduates who responded to target stimuli that appeared on a simulated security camera display at three rates of speed while completing a secondary task. Participants worked alone, in pairs, or in pairs wearing GSR sensors. Results supported the efficacy of the two models and isolated the impact of wearing sensors on the fatigue process. The strongest control variables across both the workload and fatigue models were field independence, anxiety, indecisiveness, inflexibility, secondary task completion, working in pairs, and wearing the sensors. The contributing effect of wearing sensors could possibly extend to other types of wearable technologies.

  8. Neurobehavioral Effects of Space Radiation on Psychomotor Vigilance Tests

    NASA Astrophysics Data System (ADS)

    Hienz, Robert; Davis, Catherine; Weed, Michael; Guida, Peter; Gooden, Virginia; Brady, Joseph; Roma, Peter

    Neurobehavioral Effects of Space Radiation on Psychomotor Vigilance Tests INTRODUCTION Risk assessment of the biological consequences of living in the space radiation environment represents one of the highest priority areas of NASA radiation research. Of critical importance is the need for a risk assessment of damage to the central nervous system (CNS) leading to functional cognitive/behavioral changes during long-term space missions, and the development of effective shielding or biological countermeasures to such risks. The present research focuses on the use of an animal model that employs neurobehavioral tests identical or homologous to those currently in use in human models of risk assessment by U.S. agencies such as the Depart-ment of Defense and Federal Aviation and Federal Railroad Administrations for monitoring performance and estimating accident risks associated with such variables as fatigue and/or alcohol or drug abuse. As a first approximation for establishing human risk assessments due to exposure to space radiation, the present work provides animal performance data obtained with the rPVT (rat Psychomotor Vigilance Test), an animal analog of the human PVT that is currently employed for human risk assessments via quantification of sustained attention (e.g., 'vigilance' or 'readiness to perform' tasks). Ground-based studies indicate that radiation can induce neurobehavioral changes in rodents, including impaired performance on motor tasks and deficits in spatial learning and memory. The present study is testing the hypothesis that radiation exposure impairs motor function, performance accuracy, vigilance, motivation, and memory in adult male rats. METHODS The psychomotor vigilance test (PVT) was originally developed as a human cognitive neurobe-havioral assay for tracking the temporally dynamic changes in sustained attention, and has also been used to track changes in circadian rhythm. In humans the test requires responding to a small, bright

  9. Adaptive Measurement of Vigilance Decrement.

    ERIC Educational Resources Information Center

    Wiener, E. L.

    1973-01-01

    Research investigated the utility of an alternative technique for the study of vigilance performance. The usual approach has been to study how well subjects responded to a signal of given difficulty; this technique altered the difficulty of the task to ensure a fixed level of performance. A computer-based, self-adjusting program presented…

  10. The use of music with young children to improve sustained attention during a vigilance task in the presence of auditory distractions.

    PubMed

    Wolfe, David E; Noguchi, Laura K

    2009-01-01

    The purpose of this study was to examine the use of music to sustain attention of young children during conditions of auditory distractions. Kindergarten students (N=76) were randomly assigned to one of four conditions/groups: (a) spoken story with no distraction, (b) spoken story with distraction, (c) musical story with no distraction, musical story with distraction. Participants were asked to listen to the story and to identify specific "actions" and "animals" that were presented (i.e., spoken or sung) within the story. A tally of correct responses (child pointed to correct actions/animals at appropriate times) was recorded during the listening task. Observations of participants' behaviors while listening were also made by the experimenter using narrative recording procedures. A one-way ANOVA was computed to assess the difference in mean scores across the four experimental conditions. Significant results were found. Further analysis employing a Tukey post hoc/multiple comparisons test revealed significant differences between the spoken story with distraction condition and the musical story with distraction condition. These statistical results, along with the observations of listening behaviors, were discussed in terms of providing suggestions for future research and in lending support to the use of music with young children to improve vigilance within educational and clinical settings.

  11. Neurobehavioral Effects of Space Radiation on Psychomotor Vigilance Tests

    NASA Astrophysics Data System (ADS)

    Hienz, Robert; Davis, Catherine; Weed, Michael; Guida, Peter; Gooden, Virginia; Brady, Joseph; Roma, Peter

    Neurobehavioral Effects of Space Radiation on Psychomotor Vigilance Tests INTRODUCTION Risk assessment of the biological consequences of living in the space radiation environment represents one of the highest priority areas of NASA radiation research. Of critical importance is the need for a risk assessment of damage to the central nervous system (CNS) leading to functional cognitive/behavioral changes during long-term space missions, and the development of effective shielding or biological countermeasures to such risks. The present research focuses on the use of an animal model that employs neurobehavioral tests identical or homologous to those currently in use in human models of risk assessment by U.S. agencies such as the Depart-ment of Defense and Federal Aviation and Federal Railroad Administrations for monitoring performance and estimating accident risks associated with such variables as fatigue and/or alcohol or drug abuse. As a first approximation for establishing human risk assessments due to exposure to space radiation, the present work provides animal performance data obtained with the rPVT (rat Psychomotor Vigilance Test), an animal analog of the human PVT that is currently employed for human risk assessments via quantification of sustained attention (e.g., 'vigilance' or 'readiness to perform' tasks). Ground-based studies indicate that radiation can induce neurobehavioral changes in rodents, including impaired performance on motor tasks and deficits in spatial learning and memory. The present study is testing the hypothesis that radiation exposure impairs motor function, performance accuracy, vigilance, motivation, and memory in adult male rats. METHODS The psychomotor vigilance test (PVT) was originally developed as a human cognitive neurobe-havioral assay for tracking the temporally dynamic changes in sustained attention, and has also been used to track changes in circadian rhythm. In humans the test requires responding to a small, bright

  12. Effects of environmental stressors on vigilance performance

    SciTech Connect

    Duchon, J.C.; Hudock, S.D.

    1989-01-01

    The authors report on research for reducing accidents and improving the person-machine interface found in surface and underground mining operations. Miners are exposed to a variety of environmental stressors, e.g., extreme heat, noise, vibration, and adverse illumination, throughout the workday. Exposure to these environmental stressors has been noted to affect performance of vigilance tasks. Since impaired performance of vigilance tasks can lead to industrial accidents, further investigation of the effects of environmental stressors on human performance is warranted. A description of the environmental conditions present in the mining workplace is presented. A review of experiments dealing with the effects of environmental stressors on vigilance task performance is given. The applicability of past research to actual mining operations is considered.

  13. Vigilance: A Review of the Literature and Applications to Sentry Duty

    SciTech Connect

    See, Judi E.

    2014-09-01

    Vigilance , or sustained attention, involves the ability to maintain focus and remain alert for prolonged periods of time. Problems associated with the ability to sustain attention were first identified in real-world combat situations during World War II, and they continue to abound and evolve as new and different types of situations requiring vigilance arise. This paper provides a review of the vigilance literature that describes the primary psychophysical, task, environmental, pharmacological, and individual factors that impact vigilance performance. The paper also describes how seminal findings from vigilance research apply specifically to the task of sentry duty. The strengths and weaknesses of a human sentry and options to integrate human and automated functions for vigilance tasks are discussed. Finally, techniques that may improve vigilance performance for sentry duty tasks are identified.

  14. Anticipation of Monetary Reward Can Attenuate the Vigilance Decrement

    PubMed Central

    Grosso, Mallory; Liu, Guanyu; Mitko, Alex; Morris, Rachael; DeGutis, Joseph

    2016-01-01

    Motivation and reward can have differential effects on separate aspects of sustained attention. We previously demonstrated that continuous reward/punishment throughout a sustained attention task improves overall performance, but not vigilance decrements. One interpretation of these findings is that vigilance decrements are due to resource depletion, which is not overcome by increasing overall motivation. However, an alternative explanation is that as one performs a continuously rewarded task there are less potential gains/losses as the task progresses, which could decrease motivation over time, producing a vigilance decrement. This would predict that keeping future gains/losses consistent throughout the task would reduce the vigilance decrement. In the current study, we examined this possibility by comparing two versions (continuous-small loss vs. anticipate-large loss) of a 10-minute gradual onset continuous performance task (gradCPT), a challenging go/no-go sustained attention task. Participants began each task with the potential to keep $18. In the continuous-small-loss version, small monetary losses were accrued continuously throughout the task for each error. However, in the anticipate-large-loss version, participants lost all $18 if they erroneously responded to one target that always appeared toward the end of the vigil. Typical vigilance decrements were observed in the continuous-small-loss condition. In the anticipate-large-loss condition, vigilance decrements were reduced, particularly when the anticipate-large loss condition was completed second. This suggests that the looming possibility of a large loss can attenuate the vigilance decrement and that this attenuation may occur most consistently after sufficient task experience. We discuss these results in the context of current theories of sustained attention. PMID:27472785

  15. Anticipation of Monetary Reward Can Attenuate the Vigilance Decrement.

    PubMed

    Esterman, Michael; Grosso, Mallory; Liu, Guanyu; Mitko, Alex; Morris, Rachael; DeGutis, Joseph

    2016-01-01

    Motivation and reward can have differential effects on separate aspects of sustained attention. We previously demonstrated that continuous reward/punishment throughout a sustained attention task improves overall performance, but not vigilance decrements. One interpretation of these findings is that vigilance decrements are due to resource depletion, which is not overcome by increasing overall motivation. However, an alternative explanation is that as one performs a continuously rewarded task there are less potential gains/losses as the task progresses, which could decrease motivation over time, producing a vigilance decrement. This would predict that keeping future gains/losses consistent throughout the task would reduce the vigilance decrement. In the current study, we examined this possibility by comparing two versions (continuous-small loss vs. anticipate-large loss) of a 10-minute gradual onset continuous performance task (gradCPT), a challenging go/no-go sustained attention task. Participants began each task with the potential to keep $18. In the continuous-small-loss version, small monetary losses were accrued continuously throughout the task for each error. However, in the anticipate-large-loss version, participants lost all $18 if they erroneously responded to one target that always appeared toward the end of the vigil. Typical vigilance decrements were observed in the continuous-small-loss condition. In the anticipate-large-loss condition, vigilance decrements were reduced, particularly when the anticipate-large loss condition was completed second. This suggests that the looming possibility of a large loss can attenuate the vigilance decrement and that this attenuation may occur most consistently after sufficient task experience. We discuss these results in the context of current theories of sustained attention. PMID:27472785

  16. Drivers' misjudgement of vigilance state during prolonged monotonous daytime driving.

    PubMed

    Schmidt, Eike A; Schrauf, Michael; Simon, Michael; Fritzsche, Martin; Buchner, Axel; Kincses, Wilhelm E

    2009-09-01

    To investigate the effects of monotonous daytime driving on vigilance state and particularly the ability to judge this state, a real road driving study was conducted. To objectively assess vigilance state, performance (auditory reaction time) and physiological measures (EEG: alpha spindle rate, P3 amplitude; ECG: heart rate) were recorded continuously. Drivers judged sleepiness, attention to the driving task and monotony retrospectively every 20 min. Results showed that prolonged daytime driving under monotonous conditions leads to a continuous reduction in vigilance. Towards the end of the drive, drivers reported a subjectively improved vigilance state, which was contrary to the continued decrease in vigilance as indicated by all performance and physiological measures. These findings indicate a lack of self-assessment abilities after approximately 3h of continuous monotonous daytime driving.

  17. Neuroticism and vigilance revisited: A transcranial doppler investigation.

    PubMed

    Mandell, Arielle R; Becker, Alexandra; VanAndel, Aaron; Nelson, Andrew; Shaw, Tyler H

    2015-11-01

    Selecting for vigilance assignments remains an important factor in human performance research. The current study revisits the potential relationship between vigilance performance and trait neuroticism, in light of two possible theories. The first theory suggests that neuroticism impairs vigilance performance by competing for available resources. The second theory, attentional control theory, posits that high neuroticism can result in similar or superior performance levels due to the allocation of compensatory effort. In the present study, Transcranial Doppler Sonography was used to investigate the neurophysiological underpinnings of neuroticism during a 12-min abbreviated vigilance task. Performance results were not modified by level of neuroticism, but high neuroticism was associated with higher initial CBFV levels and a greater CBFV decrement over time. These findings indicate that participants higher in neuroticism recruited additional cognitive resources in order to achieve similar performance, suggesting that there is more of an effect on processing efficiency than effectiveness.

  18. EEG predictors of covert vigilant attention

    NASA Astrophysics Data System (ADS)

    Martel, Adrien; Dähne, Sven; Blankertz, Benjamin

    2014-06-01

    Objective. The present study addressed the question whether neurophysiological signals exhibit characteristic modulations preceding a miss in a covert vigilant attention task which mimics a natural environment in which critical stimuli may appear in the periphery of the visual field. Approach. Subjective, behavioural and encephalographic (EEG) data of 12 participants performing a modified Mackworth Clock task were obtained and analysed offline. The stimulus consisted of a pointer performing regular ticks in a clockwise sequence across 42 dots arranged in a circle. Participants were requested to covertly attend to the pointer and press a response button as quickly as possible in the event of a jump, a rare and random event. Main results. Significant increases in response latencies and decreases in the detection rates were found as a function of time-on-task, a characteristic effect of sustained attention tasks known as the vigilance decrement. Subjective sleepiness showed a significant increase over the duration of the experiment. Increased activity in the α-frequency range (8-14 Hz) was observed emerging and gradually accumulating 10 s before a missed target. Additionally, a significant gradual attenuation of the P3 event-related component was found to antecede misses by 5 s. Significance. The results corroborate recent findings that behavioural errors are presaged by specific neurophysiological activity and demonstrate that lapses of attention can be predicted in a covert setting up to 10 s in advance reinforcing the prospective use of brain-computer interface (BCI) technology for the detection of waning vigilance in real-world scenarios. Combining these findings with real-time single-trial analysis from BCI may pave the way for cognitive states monitoring systems able to determine the current, and predict the near-future development of the brain's attentional processes.

  19. Sleep, vigilance, and thermosensitivity.

    PubMed

    Romeijn, Nico; Raymann, Roy J E M; Møst, Els; Te Lindert, Bart; Van Der Meijden, Wisse P; Fronczek, Rolf; Gomez-Herrero, German; Van Someren, Eus J W

    2012-01-01

    The regulation of sleep and wakefulness is well modeled with two underlying processes: a circadian and a homeostatic one. So far, the parameters and mechanisms of additional sleep-permissive and wake-promoting conditions have been largely overlooked. The present overview focuses on one of these conditions: the effect of skin temperature on the onset and maintenance of sleep, and alertness. Skin temperature is quite well suited to provide the brain with information on sleep-permissive and wake-promoting conditions because it changes with most if not all of them. Skin temperature changes with environmental heat and cold, but also with posture, environmental light, danger, nutritional status, pain, and stress. Its effect on the brain may thus moderate the efficacy by which the clock and homeostat manage to initiate or maintain sleep or wakefulness. The review provides a brief overview of the neuroanatomical pathways and physiological mechanisms by which skin temperature can affect the regulation of sleep and vigilance. In addition, current pitfalls and possibilities of practical applications for sleep enhancement are discussed, including the recent finding of impaired thermal comfort perception in insomniacs.

  20. Correlated fluctuations of daytime skin temperature and vigilance.

    PubMed

    Romeijn, Nico; Van Someren, Eus J W

    2011-02-01

    Skin temperature shows spontaneous ultradian fluctuations during everyday-life wakefulness. Previous work showed that mild manipulations of skin temperature affect human sleep and vigilance, presumably by influencing neuronal systems involved in both thermal sensing and arousal regulation. We therefore examined whether fluctuations in skin temperature are associated with those in vigilance level under conditions similar to everyday-life situations requiring sustained attention. Eight healthy participants (30.1 ± 8.1 years, M ± SD) participated in a 2-day protocol, during which vigilance and skin temperature were assessed 4 times per day in a silent, dimly lit, temperature-controlled room. Vigilance was assessed by measuring reaction speed and lapses on a novel sustained vigilance task specifically designed to increase lapse rate and range of reaction times. Skin temperature was sampled at 30-second intervals from 3 locations: distal, intermediate, and proximal temperatures were obtained from the middle finger (T(finger) ), the wrist (T(wrist)), and the infraclavicular area (T(chest)), respectively. Furthermore, 3 distal to proximal gradients were calculated. Mixed-effect regression analyses were used to evaluate the association of the fluctuations in temperatures and gradients and those in response speed and lapse probability. Especially the spontaneous fluctuations in proximal temperature were negatively associated with fluctuations in response speed and positively with lapse rate. If individual T(chest) temperature ranges were classified into 10 deciles, they accounted for 23% of the variance in response speed and 11% of the variance in lapse rate. The findings indicate coupling between the spontaneous fluctuations in skin temperature and vigilance during the day and are compatible with the hypothesis of overlap in brain networks involved in the regulation of temperature and vigilance. From an applied point of view, especially proximal skin temperature

  1. EEG and Eye Tracking Demonstrate Vigilance Enhancement with Challenge Integration.

    PubMed

    Bodala, Indu P; Li, Junhua; Thakor, Nitish V; Al-Nashash, Hasan

    2016-01-01

    Maintaining vigilance is possibly the first requirement for surveillance tasks where personnel are faced with monotonous yet intensive monitoring tasks. Decrement in vigilance in such situations could result in dangerous consequences such as accidents, loss of life and system failure. In this paper, we investigate the possibility to enhance vigilance or sustained attention using "challenge integration," a strategy that integrates a primary task with challenging stimuli. A primary surveillance task (identifying an intruder in a simulated factory environment) and a challenge stimulus (periods of rain obscuring the surveillance scene) were employed to test the changes in vigilance levels. The effect of integrating challenging events (resulting from artificially simulated rain) into the task were compared to the initial monotonous phase. EEG and eye tracking data is collected and analyzed for n = 12 subjects. Frontal midline theta power and frontal theta to parietal alpha power ratio which are used as measures of engagement and attention allocation show an increase due to challenge integration (p < 0.05 in each case). Relative delta band power of EEG also shows statistically significant suppression on the frontoparietal and occipital cortices due to challenge integration (p < 0.05). Saccade amplitude, saccade velocity and blink rate obtained from eye tracking data exhibit statistically significant changes during the challenge phase of the experiment (p < 0.05 in each case). From the correlation analysis between the statistically significant measures of eye tracking and EEG, we infer that saccade amplitude and saccade velocity decrease with vigilance decrement along with frontal midline theta and frontal theta to parietal alpha ratio. Conversely, blink rate and relative delta power increase with vigilance decrement. However, these measures exhibit a reverse trend when challenge stimulus appears in the task suggesting vigilance enhancement. Moreover, the mean reaction

  2. EEG and Eye Tracking Demonstrate Vigilance Enhancement with Challenge Integration

    PubMed Central

    Bodala, Indu P.; Li, Junhua; Thakor, Nitish V.; Al-Nashash, Hasan

    2016-01-01

    Maintaining vigilance is possibly the first requirement for surveillance tasks where personnel are faced with monotonous yet intensive monitoring tasks. Decrement in vigilance in such situations could result in dangerous consequences such as accidents, loss of life and system failure. In this paper, we investigate the possibility to enhance vigilance or sustained attention using “challenge integration,” a strategy that integrates a primary task with challenging stimuli. A primary surveillance task (identifying an intruder in a simulated factory environment) and a challenge stimulus (periods of rain obscuring the surveillance scene) were employed to test the changes in vigilance levels. The effect of integrating challenging events (resulting from artificially simulated rain) into the task were compared to the initial monotonous phase. EEG and eye tracking data is collected and analyzed for n = 12 subjects. Frontal midline theta power and frontal theta to parietal alpha power ratio which are used as measures of engagement and attention allocation show an increase due to challenge integration (p < 0.05 in each case). Relative delta band power of EEG also shows statistically significant suppression on the frontoparietal and occipital cortices due to challenge integration (p < 0.05). Saccade amplitude, saccade velocity and blink rate obtained from eye tracking data exhibit statistically significant changes during the challenge phase of the experiment (p < 0.05 in each case). From the correlation analysis between the statistically significant measures of eye tracking and EEG, we infer that saccade amplitude and saccade velocity decrease with vigilance decrement along with frontal midline theta and frontal theta to parietal alpha ratio. Conversely, blink rate and relative delta power increase with vigilance decrement. However, these measures exhibit a reverse trend when challenge stimulus appears in the task suggesting vigilance enhancement. Moreover, the mean

  3. Aging and vigilance: who has the inhibition deficit?

    PubMed

    Brache, Kristina; Scialfa, Charles; Hudson, Carl

    2010-04-01

    The present study compared 18 younger (M = 21.00 years) and 17 older adults (M = 64.29 years) in a modified vigilance task that required the inhibition of a routinized response. The task was a 50-min simulation of industrial inspection, wherein observers were presented with simple displays labeled "good" and "bad" parts. General linear modeling indicated that younger adults showed a doubling of inhibition failures over time (from 19% to 43%); older adults' inhibition failures held constant at approximately 17.5%. In both age groups, those who responded most quickly were also most error-prone. A control experiment, using the traditional vigilance task requiring a response to infrequent "bad" parts, found only small age differences in accuracy and these also favored older adults. This research suggests that younger adults may demonstrate larger inhibition failures when the routinized responses on simple tasks must be suppressed. There are several implications for theory, industrial design, and cognitive assessment.

  4. A multi level system design for vigilance measurement based on head posture estimation and eyes blinking

    NASA Astrophysics Data System (ADS)

    Teyeb, Ines; Jemai, Olfa; Zaied, Mourad; ben Amar, Chokri

    2015-12-01

    Driving security is an important task for human society. The major challenge in the field of accident avoidance systems is the driver vigilance monitoring. The lack of vigilance can be noticed by various ways, such as, fatigue, drowsiness and distraction. Hence, the need of a reliable driver's vigilance decrease detection system which can alert drivers before a mishap happens. In this paper, we present a novel approach for vigilance estimation based on multilevel system by combining head movement analysis and eyes blinking. We have used Viola and Jones algorithm to analyse head movement and a classification system using wavelet networks for eyelid closure measuring. The contribution of our application is classifiying the vigilance state at multi level. This is different from the binary-class (awakening or hypovigilant state) existing in most popular systems.

  5. Vigilance problems in orbiter processing

    NASA Technical Reports Server (NTRS)

    Swart, William W.; Safford, Robert R.; Kennedy, David B.; Yadi, Bert A.; Barth, Timothy S.

    1993-01-01

    A pilot experiment was done to determine what factors influence potential performance errors related to vigilance in Orbiter processing activities. The selected activities include post flight inspection for burned gap filler material and pre-rollout inspection for tile processing shim material. It was determined that the primary factors related to performance decrement were the color of the target and the difficulty of the target presentation.

  6. Work exposure and vigilance decrements in closed circuit television surveillance.

    PubMed

    Donald, Fiona; Donald, Craig; Thatcher, Andrew

    2015-03-01

    The aim of this study was to examine operator effectiveness in terms of detection rates and potential vigilance decrements in a proactive or real time CCTV surveillance task. The study was conducted in two stages. During stage one, 42 operators who were employed full-time in CCTV surveillance observed a 90-min video and were required to detect four types of target behaviours. No vigilance decrement was found for this sample as a whole. Stage two involved collecting additional data from 31 novices and dividing the existing operators into two sub-samples, consisting of generalists and specialists depending on the type of surveillance they performed at work (total N = 73). Fifty percent of target behaviours were detected and false alarms were high. Vigilance decrements were found for novices and generalists, but specialists maintained their performance for the first hour and then increased it. Results are discussed in terms of surveillance background, work exposure, transfer of learning, selection, training and motivation and the impact of these on vigilance and CCTV performance.

  7. Effects of signal salience and noise on performance and stress in an abbreviated vigil

    NASA Astrophysics Data System (ADS)

    Helton, William Stokely

    Vigilance or sustained attention tasks traditionally require observers to detect predetermined signals that occur unpredictably over periods of 30 min to several hours (Warm, 1984). These tasks are taxing and have been useful in revealing the effects of stress agents, such as infectious disease and drugs, on human performance (Alluisi, 1969; Damos & Parker, 1994; Warm, 1993). However, their long duration has been an inconvenience. Recently, Temple and his associates (Temple et al., 2000) developed an abbreviated 12-min vigilance task that duplicates many of the findings with longer duration vigils. The present study was designed to explore further the similarity of the abbreviated task to long-duration vigils by investigating the effects of signal salience and jet-aircraft engine noise on performance, operator stress, and coping strategies. Forty-eight observers (24 males and 24 females) were assigned at random to each of four conditions resulting from the factorial combination of signal salience (high and low contrast signals) and background noise (quiet and jet-aircraft noise). As is the case with long-duration vigils (Warm, 1993), signal detection in the abbreviated task was poorer for low salience than for high salience signals. In addition, stress scores, as indexed by the Dundee Stress State Questionnaire (Matthews, Joiner, Gilliland, Campbell, & Falconer, 1999), were elevated in the low as compared to the high salience condition. Unlike longer vigils, however, (Becker, Warm, Dember, & Hancock, 1996), signal detection in the abbreviated task was superior in the presence of aircraft noise than in quiet. Noise also attenuated the stress of the vigil, a result that is counter to previous findings regarding the effects of noise in a variety of other scenarios (Clark, 1984). Examination of observers' coping responses, as assessed by the Coping Inventory for Task Situations (Matthews & Campbell, 1998), indicated that problem-focused coping was the overwhelming

  8. The influence of essential oils on human vigilance.

    PubMed

    Heuberger, Eva; Ilmberger, Josef

    2010-09-01

    Olfactory stimuli are used in aromatherapy to enhance mood, well-being and work efficiency. Nevertheless, the impact of fragrances on cognitive performance in humans is not well understood. The present investigation aimed to evaluate the effects of 1,8-cineol, jasmine absolute ether, linalyl acetate and peppermint essential oil on human vigilance performance. The odorants were administered by means of inhalation and, except for peppermint essential oil, were tested at 2 different dosages. Performance in a standard visual vigilance task was measured in terms of speed and accuracy and subjective ratings of the odorants were assessed in terms of pleasantness, intensity, arousal and stress. We hypothesized that 1,8-cineol, jasmine absolute ether and peppermint essential oil would improve vigilance performance, whereas linalyl acetate would impair such performance. Comparison of the performances of the seven independent experimental groups with that of a control group did not show any of the expected effects. In contrast, inhalation of linalyl acetate decreased reaction times. Within-group analyses, however, revealed significant interactions between subjective ratings of the odorants and task performance. The results of the present investigation emphasize the high impact of subjective factors on the modulation of attentional functions by olfactory stimuli in humans. PMID:20923005

  9. The effects of different modes of supervision on vigilance behaviour.

    PubMed

    Putz, V R

    1975-05-01

    Experiment I was run to determine if a closed-circuit television and a one-way window mode of supervision were as effective as the direct physical presence of an experimenter in inducing enhanced levels of signal detection in a Mackworth-type vigilance task. A control condition of complete subject privacy was also examined. The results indicated that both the television and the window conditions had a positive effect on overall performance which was similar to that observed in the experimenter-presence condition; however, the performance decrement over the 90 min vigil was equivalent for the four modes. A second experiment involving the variable of camera position with an addition of a fourth 30 min. period yielded no significant differences between the camera positions, but overall performance in the television condition was again better than in the control condition. This study suggested that performance can be enhanced even without the physical presence of the experimenter. PMID:1156737

  10. Motivation in vigilance - Effects of self-evaluation and experimenter-controlled feedback.

    NASA Technical Reports Server (NTRS)

    Warm, J. S.; Kanfer, F. H.; Kuwada, S.; Clark, J. L.

    1972-01-01

    Vigilance experiments have been performed to study the relative efficiency of feedback operations in enhancing vigilance performance. Two feedback operations were compared - i.e., experimenter-controlled feedback in the form of knowledge of results (KR) regarding response times to signal detections, and subject-controlled feedback in the form of self-evaluation (SE) of response times to signal detections. The subjects responded to the aperiodic offset of a visual signal during a 1-hr vigil. Both feedback operations were found to enhance performance efficiency: subjects in the KR and SE conditions had faster response times than controls receiving no evaluative feedback. Moreover, the data of the KR and SE groups did not differ significantly from each other. The results are discussed in terms of the hypothesis that self-evaluation is a critical factor underlying the incentive value of KR in vigilance tasks.

  11. The 5-Choice Continuous Performance Test: Evidence for a Translational Test of Vigilance for Mice

    PubMed Central

    Young, Jared W.; Light, Gregory A.; Marston, Hugh M.; Sharp, Richard; Geyer, Mark A.

    2009-01-01

    Background Attentional dysfunction is related to functional disability in patients with neuropsychiatric disorders such as schizophrenia, bipolar disorder, and Alzheimer's disease. Indeed, sustained attention/vigilance is among the leading targets for new medications designed to improve cognition in schizophrenia. Although vigilance is assessed frequently using the continuous performance test (CPT) in humans, few tests specifically assess vigilance in rodents. Methods We describe the 5-choice CPT (5C-CPT), an elaboration of the 5-choice serial reaction (5CSR) task that includes non-signal trials, thus mimicking task parameters of human CPTs that use signal and non-signal events to assess vigilance. The performances of C57BL/6J and DBA/2J mice were assessed in the 5C-CPT to determine whether this task could differentiate between strains. C57BL/6J mice were also trained in the 5CSR task and a simple reaction-time (RT) task involving only one choice (1CRT task). We hypothesized that: 1) C57BL/6J performance would be superior to DBA/2J mice in the 5C-CPT as measured by the sensitivity index measure from signal detection theory; 2) a vigilance decrement would be observed in both strains; and 3) RTs would increase across tasks with increased attentional load (1CRT task<5CSR task<5C-CPT). Conclusions C57BL/6J mice exhibited superior SI levels compared to DBA/2J mice, but with no difference in accuracy. A vigilance decrement was observed in both strains, which was more pronounced in DBA/2J mice and unaffected by response bias. Finally, we observed increased RTs with increased attentional load, such that 1CRT task<5CSR task<5C-CPT, consistent with human performance in simple RT, choice RT, and CPT tasks. Thus we have demonstrated construct validity for the 5C-CPT as a measure of vigilance that is analogous to human CPT studies. PMID:19156216

  12. The effects of sleep debt on vigilance in young drivers: an education/research project in high schools.

    PubMed

    Lucidi, Fabio; Devoto, Alessandra; Bertini, Mario; Braibanti, Paride; Violani, Cristiano

    2002-08-01

    The vigilance levels of a group of 59 students were assessed in the daytime (9:00-11:00 a.m.) and again early Sunday morning (2:30-5:00 a.m.), and were then compared. Data were collected at the students' schools. The differences in performance impairment associated with different Saturday night social activities and the effect of alcohol consumption were evaluated. Results indicate a vigilance decrease during the night, and this is greater in subjects who consumed more alcohol. Students who spent their Saturday night in a discotheque showed the most prominent nocturnal vigilance decrease, even when the effect of alcohol consumption is covaried. The effect of social activities on vigilance levels was also associated with different lengths of time spent awake and the different time in which subjects performed the vigilance task. PMID:12175997

  13. The Academic Legacy of Berta Vigil Laden

    ERIC Educational Resources Information Center

    Hagedorn, Linda Serra

    2007-01-01

    Berta Vigil Laden was a scholar who helped raise our understanding of minority-serving institutions generally and Hispanic-serving institutions in particular. She approached her work with empathy and compassion. This article reviews her major contributions.

  14. [Vigilance and fearfulness of reindeer: population differences].

    PubMed

    Baskin, L M; Skugland, T

    2001-01-01

    Distances of detection and flight away of reindeer disturbed by approaching human on foot were used to compare reindeer alertness and vigilance. Population differences depended on genetic origin (wild, feral, and tame reindeer) and hunting. No correlations of vigilance and alertness were found with presence of predators, sex composition of herds, and presence of newborns in herd. Herd size affecting jointly with genetic origin or hunting had negative correlation with alertness.

  15. Sensory Modality, Temperament, and the Development of Sustained Attention: A Vigilance Study in Children and Adults

    ERIC Educational Resources Information Center

    Curtindale, Lori; Laurie-Rose, Cynthia; Bennett-Murphy, Laura; Hull, Sarah

    2007-01-01

    Applying optimal stimulation theory, the present study explored the development of sustained attention as a dynamic process. It examined the interaction of modality and temperament over time in children and adults. Second-grade children and college-aged adults performed auditory and visual vigilance tasks. Using the Carey temperament…

  16. The relationship between regular sports participation and vigilance in male and female adolescents.

    PubMed

    Ballester, Rafael; Huertas, Florentino; Yuste, Francisco Javier; Llorens, Francesc; Sanabria, Daniel

    2015-01-01

    The present study investigated the relationship between regular sport participation (soccer) and vigilance performance. Two groups of male and female adolescents differentiated in terms of their sport participation (athletes, n = 39, and non-athletes, n = 36) took part in the study. In one session, participants performed the Leger Multi-stage fitness test to estimate their aerobic fitness level. In the other session, participants completed the Psychomotor Vigilance Task (PVT) to evaluate their vigilance performance. Perceived arousal prior to the task and motivation toward the task were also measured in the PVT session. The results revealed that athletes had better cardiovascular fitness and showed better performance in the PVT. However, correlation analyses did not show any significant relationship between cardiovascular fitness and performance in the PVT. Athletes showed larger scores in motivation and perceived arousal measures with respect to non-athletes, although, once again, these variables were not correlated with PVT performance. Gender differences were observed only in the Leger test, with males showing greater fitness level than females. The major outcome of this research points to a positive relationship between regular sport participation and vigilance during adolescence. This relationship did not seem to be influenced by gender, perceived arousal, motivation toward the task or cardiovascular fitness. We discuss our results in terms of the different hypotheses put forward in the literature to explain the relationship between physical activity and cognitive functioning. PMID:25849873

  17. Effects of chronotype and time of day on the vigilance decrement during simulated driving.

    PubMed

    Correa, Angel; Molina, Enrique; Sanabria, Daniel

    2014-06-01

    The current study tested for the first time the effect of individual differences in circadian rhythmicity (chronotype) on both driving performance and its evolution along time on task. Morning-type and evening-type female participants were tested in morning (8 am) and evening (8 pm) sessions, in which we controlled for prior sleep duration and prior wake. Measures of body temperature, subjective activation and affect, reaction times (RT) in the Psychomotor Vigilance Task (PVT), behavioral performance (error position) and EEG alpha power during simulated driving were collected. The main result showed strong linear increments of mean and standard deviation of error position along time on task (vigilance decrement) when evening-type participants drove at their non-optimal time of day, that is, during the morning session. In contrast, driving performance in the morning-type group remained stable over time on task and was not affected by time of day. This finding can be due to differences in personality traits (e.g., conscientiousness, sensation seeking) and task appraisal associated to extreme chronotypes. The consideration of chronotype in vigilance and driving tasks can enhance safety and human performance by promoting work schedules and countermeasures to prevent failures in the accomplishment of tasks under non-optimal circadian conditions. PMID:24636873

  18. Enhancing vigilance in operators with prefrontal cortex transcranial direct current stimulation (tDCS).

    PubMed

    Nelson, Jeremy T; McKinley, R Andy; Golob, Edward J; Warm, Joel S; Parasuraman, Raja

    2014-01-15

    Sustained attention, often referred to as vigilance in humans, is the ability to maintain goal-directed behavior for extended periods of time and respond to intermittent targets in the environment. With greater time-on-task the ability to detect targets decreases and reaction time increases-a phenomenon termed the vigilance decrement. The purpose of this study was to examine the role of dorsolateral prefrontal cortex in the vigilance decrement. Subjects (n=19) received prefrontal transcranial direct current stimulation (tDCS) at one of two different time points during a vigilance task (early or late). The impact of tDCS was examined using measures of behavior, hemispheric blood flow velocity, and regional blood oxygenation relative to sham stimulation. In the sham condition greater time-on-task was accompanied by fewer target detections and slower reaction times, indicating a vigilance decrement, and decreased blood flow velocity. tDCS significantly altered baseline task-induced physiologic and behavioral changes, dependent on the time of stimulation administration and electrode configuration (determining polarity of stimulation). Compared to the sham condition, with more time-on-task blood flow velocity decreased less and cerebral oxygenation increased more in the tDCS condition. Behavioral measures showed a significant improvement in target detection performance with tDCS compared to the sham stimulation. Signal detection analysis revealed a significant change in operator discriminability and response bias with increased time-on-task, as well as interactions between time of stimulation administration and electrode configuration. Current density modeling of tDCS showed high densities in the medial prefrontal cortex and anterior cingulate cortex. These findings confirm that cerebral hemodynamic measures provide an index of resource utilization and point to the central role of the frontal cortex in vigilance. Further, they suggest that modulation of the frontal

  19. Looking for trouble: revenge-planning and preattentive vigilance for angry facial expressions.

    PubMed

    Crowe, Sarah E; Wilkowski, Benjamin M

    2013-08-01

    Revenge-planning refers to individual differences in the tendency to actively seek out hostile confrontations with others. Building on past theory, we hypothesized that revenge-planning would be related to preattentive vigilance for angry facial expressions. By being vigilant for such expressions, individuals could more readily notice and prepare to confront social challenges. We conducted 2 studies to test this prediction. Across studies, results indicated that participants high in revenge-planning had significantly longer color-naming latencies for masked angry expressions presented in a subliminal Stroop task, regardless of whether the expression was presented inside or outside participants' attentional focus. This phenomenon was specific to revenge-planning and did not extend to the related construct of angry rumination. Such results suggest that preattentive vigilance for angry expressions supports a confrontational social style in which a person actively seeks out hostile social encounters. PMID:23527511

  20. Effects of a biocybernetic system on vigilance performance.

    PubMed

    Mikulka, Peter J; Scerbo, Mark W; Freeman, Frederick G

    2002-01-01

    The present study was designed to determine whether a biocybernetic, adaptive system could enhance vigilance performance. Participants were asked to monitor the repetitive presentation of white bars on a computer screen for occasional increases in length. An index of task engagement was derived from participants' electroencephalographic (EEG) activity and was used to change the presentation rate of events among 3 values (6, 20, and 60 events/min). Under a negative feedback contingency, event rates increased if the engagement index decreased and, conversely, decreased if the index increased. Under positive feedback, the opposite contingency existed. Each experimental participant had a yoked control partner who received the same pattern of changes in event rates irrespective of his or her EEG activity. The results showed that better vigilance performance was obtained under negative feedback and that the performance of the yoked participants was similar to that of their experimental partners. These findings suggest that it may be possible to improve monitoring performance on critical activities such as air traffic control and radar and sonar operation through a pattern of event rate changes that do not rely on an operator's overt behavior.

  1. Does hallucination affect vigilance performance in schizophrenia? An exploratory study.

    PubMed

    Das, Sudeshna; Ray, Deepshikha; Banerjee, Mallika

    2011-09-01

    The present study investigates the role of "auditory verbal hallucination" (AVH) in the attentional processes of individuals diagnosed with schizophrenia compared with healthy participants. The sample consisted of 26 participants diagnosed with schizophrenia divided into - "schizophrenia with hallucination" (N=12) and "schizophrenia without hallucination" (N=14). 13 matched healthy participants were taken. A general health questionnaire was used to screen out psychiatric morbidity in healthy participants. The presence and/or absence of AVH were substantiated through the administration of the Positive and Negative Syndrome Scale (PANSS). Only individuals having higher composite scores in the positive scale were included. Edinburgh Handedness Inventory was administered to all participants. Software designed to measure vigilance was used to assess attentional deficits in the three groups included in the study. The complexity of the "vigilance task" was varied across three parameters: (1) spatial position of the target stimulus and buffer, (2) frequency of the target stimulus and buffer and (3) colour of target stimulus and buffer. The performances of the 3 groups were compared statistically in terms of Hit, Miss and False Alarm scores. Results revealed that schizophrenia patients are deficient as compared to their healthy counterparts in the ability to focus on a specific target while inhibiting non-relevant information across all conditions. Also, schizophrenia patients who have AVH are relatively more deficient as compared to the schizophrenia patients without AVH. It can be concluded that perceptual abnormality in schizophrenia patients with hallucination has an additional negative impact on attentional processes. PMID:23051117

  2. The Effects of Eight-Month Physical Activity Intervention on Vigilance Performance in Adult Obese Population.

    PubMed

    Monleón, Cristina; Ballester, Rafael; Sanchis, Carlos; Llorens, Francesc; Martín, Marta; Pablos, Ana

    2015-01-01

    We aim to analyze the effects of an 8-month physical activity intervention on cardiorespiratory fitness, body mass index (BMI), and vigilance performance in an adult obese population. We conducted an 8-month physical activity intervention based on dance and rhythmic activities. The weekly frequency was 2 sessions of 1 hr per day. Training sessions were divided into 3 phases: a 10-min warm-up, 40 min of dance and rhythmic activities, and 10 min to cool-down. To assess cardiorespiratory fitness, participants performed a modified version of the 6-min walk test from the Senior Fitness Test battery (Larsson & Mattsson, 2001; Rikli & Jones, 1999). Vigilance performance was measured by means of the psychomotor vigilance task (PVT). Two measurements were performed immediately before and after the intervention. The results revealed that participants improved their cardiorespiratory fitness, BMI, and vigilance performance after the intervention. All in all, findings contribute new empirical evidence to the field that investigates the benefits of physical activity intervention on cognitive processes in obese population.

  3. The vigilance regulation model of affective disorders and ADHD.

    PubMed

    Hegerl, Ulrich; Hensch, Tilman

    2014-07-01

    According to the recently proposed vigilance model of affective disorders (vigilance in the sense of "brain arousal"), manic behaviour is partly interpreted as an autoregulatory attempt to stabilise vigilance by creating a stimulating environment, and the sensation avoidance and withdrawal in Major Depressive Disorder (MDD) is seen as an autoregulatory reaction to tonically increased vigilance. Indeed, using a newly developed EEG-based algorithm, hyperstable vigilance was found in MDD, and the contrary, with rapid drops to sleep stages, in mania. Furthermore, destabilising vigilance (e.g. by sleep deprivation) triggers (hypo)mania and improves depression, whereas stabilising vigilance, e.g. by prolonged sleep, improves mania. ADHD and mania have common symptoms, and the unstable vigilance might be a common pathophysiology. There is even evidence that psychostimulants might ameliorate both ADHD and mania. Hyperactivity of the noradrenergic system could explain both the high vigilance level in MDD and, as recently argued, anhedonia and behavioural inhibition. Interestingly, antidepressants and electroconvulsions decrease the firing rate of neurons in the noradrenergic locus coeruleus, whereas many antimanic drugs have opposite effects.

  4. Vigilance as a table of numbers.

    PubMed

    Richardson, N

    1995-02-01

    Data from vigilance experiments have structure. Its bases include 1/12 and multiples thereof, single-digit fractions, and 1/e. Continuing previous research, a table of e-based ratios (e-BR) was developed. Data from 9 published experiments with regular and irregular signals (RS-IS) and from 9 with extraverted and introverted subjects (E-I) were re-analyzed. Significant numerical correlations were obtained, some concerning effects originally reported as nonsignificant. Detection (D) means all categories ("levels" of both factors) were linearly related, with p(D) approximately mean(5/8 + y/9) and p < .01. Cross-factor averaged mean products of ratio D for each time period also showed convergence (p < .01). The over-all mean and stability ratio of detections (SR[D], i.e., D for final time period/D for initial time period, gave the scaling effect 8 square root of 1/24:24 square root of 1/24. Response-time means and standard deviations for different groups in Mackie, Wylie, and Smith's 1994 sonar experiments were related by the derivatives of [1 - 1/e] included in the new table (p = .002). Although by no means specific to vigilance (or psychophysics), the numeric factor still seems relevant to research.

  5. [Interindividual differences in priming and memory effects of threatening stimuli: effect of cognitive avoidance and vigilant anxiety coping].

    PubMed

    Hock, M; Egloff, B

    1998-01-01

    This study examined the influence of dispositional coping strategies (cognitive avoidance, vigilance) on priming and memory effects of emotional stimuli. In the first phase of the study participants performed a lexical decision task that involved threat-related and neutral words. Subsequently, a previously unannounced recognition memory test for a subset of the words presented during the first phase was carried out. Repressers (i.e. individuals high in avoidance and low in vigilance) showed stronger emotional priming effects than nonavoiders. Repressers also showed a memory deficit for emotional relative to neutral words, whereas sensitizers (vigilance high, avoidance low) remembered emotional words comparatively well. Results raise the question of whether repressers' memory deficits for threat-related stimuli are actually based on a less differentiated network of emotional information, as assumed by recent theoretical accounts of individual differences in coping.

  6. Automatic vigilance: the attention-grabbing power of negative social information.

    PubMed

    Pratto, F; John, O P

    1991-09-01

    One of the functions of automatic stimulus evaluation is to direct attention toward events that may have undesirable consequences for the perceiver's well-being. To test whether attentional resources are automatically directed away from an attended task to undesirable stimuli, Ss named the colors in which desirable and undesirable traits (e.g., honest, sadistic) appeared. Across 3 experiments, color-naming latencies were consistently longer for undesirable traits but did not differ within the desirable and undesirable categories. In Experiment 2, Ss also showed more incidental learning for undesirable traits, as predicted by the automatic vigilance (but not a perceptual defense) hypothesis. In Experiment 3, a diagnosticity (or base-rate) explanation of the vigilance effect was ruled out. The implications for deliberate processing in person perception and stereotyping are discussed. PMID:1941510

  7. A Preliminary Investigation of the Reinforcement Function of Signal Detections in Simulated Baggage Screening: Further Support for the Vigilance Reinforcement Hypothesis

    ERIC Educational Resources Information Center

    Hogan, Lindsey C.; Bell, Matthew; Olson, Ryan

    2009-01-01

    The vigilance reinforcement hypothesis (VRH) asserts that errors in signal detection tasks are partially explained by operant reinforcement and extinction processes. VRH predictions were tested with a computerized baggage screening task. Our experiment evaluated the effects of signal schedule (extinction vs. variable interval 6 min) and visual…

  8. Electroencephalography Correlates of Spatial Working Memory Deficits in Attention-Deficit/Hyperactivity Disorder: Vigilance, Encoding, and Maintenance

    PubMed Central

    Delorme, Arnaud; Walshaw, Patricia D.; Cho, Alex L.; Bilder, Robert M.; McGough, James J.; McCracken, James T.; Makeig, Scott; Loo, Sandra K.

    2014-01-01

    In the current study we sought to dissociate the component processes of working memory (WM) (vigilance, encoding and maintenance) that may be differentially impaired in attention-deficit/ hyperactivity disorder (ADHD). We collected electroencephalographic (EEG) data from 52 children with ADHD and 47 typically developing (TD) children, ages 7–14 years, while they performed a spatial Sternberg working memory task. We used independent component analysis and time-frequency analysis to identify midoccipital alpha (8–12 Hz) to evaluate encoding processes and frontal midline theta (4–7 Hz) to evaluate maintenance processes. We tested for effects of task difficulty and cue processing to evaluate vigilance. Children with ADHD showed attenuated alpha band event-related desynchronization (ERD) during encoding. This effect was more pronounced when task difficulty was low (consistent with impaired vigilance) and was predictive of memory task performance and symptom severity. Correlated with alpha ERD during encoding were alpha power increases during the maintenance period (relative to baseline), suggesting a compensatory effort. Consistent with this interpretation, midfrontal theta power increases during maintenance were stronger in ADHD and in high-load memory conditions. Furthermore, children with ADHD exhibited a maturational lag in development of posterior alpha power whereas age-related changes in frontal theta power deviated from the TD pattern. Last, subjects with ADHD showed age-independent attenuation of evoked responses to warning cues, suggesting low vigilance. Combined, these three EEG measures predicted diagnosis with 70% accuracy. We conclude that the interplay of impaired vigilance and encoding in ADHD may compromise maintenance and lead to impaired WM performance in this group. PMID:24453310

  9. Vigilance patterns of Bald Eagles feeding in groups

    USGS Publications Warehouse

    Knight, Susan K.; Knight, Richard L.

    1986-01-01

    Patterns of vigilant behavior of wintering Bald Eagles (Haliaeetus leucocephalus) feeding on spawned salmon were examined in 1983-1984 on the Nooksack River in north-western Washington. Vigilance in feeding birds has, in general, been attributed to predator detection; however, we proposed an additional function of vigilance in socially feeding birds that are vulnerable to food robbery and possible injury by conspecifics. We tested predictions of two nonexclusive hypotheses: (1) eagles look up while feeding to detect danger from humans, and (2) eagles look up while feeding to detect pirating attempts or avoid injury by conspecifics. Results suggest that the function of vigilance varies, depending on the size of the feeding group. Vigilance patterns of eagles feeding in small groups (1-4 eagles) and medium groups (5-7) eagles are consistent with hypothesis 1, whereas those of eagles feeding in large groups (8-14 eagles) are consistent with hypothesis 2. Eagles in small groups were more vigilant (measured as scanning time and rate of head raising) when feeding near potential danger (riverbank cover) than when far from danger. Adult eagles feeding in areas of intense human activity were more vigilant than immatures feeding at the same site and were more vigilant than both adults and immatures feeding at secluded sites. Vigilance declined as group size increased from 1 to 4 eagles, and increased as group size ranged from 8 to 14 eagles. Feedings eagles that were looking up at the time of a pirating attempt were more successful in keeping their food than eagles with their heads down. In feeding areas where human activity was minimal, eagles formed larger groups than at a more disturbed site.

  10. Application of vigilance research - Rare, medium, or well done?

    NASA Technical Reports Server (NTRS)

    Wiener, Earl L.

    1987-01-01

    In the years since Mackworth (1950) initiated research into problems of human vigilance, automated systems have become more complex and costly, with greater repercussions upon failure; this has led to a paradoxical enhancement of human monitoring's importance. Applications of vigilance research to well-designed systems that take human monitoring into account are rare, although the outlook for future systems is improving. Attention is presently given to problems encountered in considerations of signal rate, length of vigil, time decrements, and two examples of implementation from commercial aviation.

  11. Neighborhood Vigilance, Health Locus of Control, and Smoking Abstinence

    PubMed Central

    Reitzel, Lorraine R.; Lahoti, Sejal; Li, Yisheng; Cao, Yumei; Wetter, David W.; Waters, Andrew J.; Vidrine, Jennifer Irvin

    2012-01-01

    Objectives To examine whether health locus of control mediated relations of self-reported neighborhood vigilance and biochemically verified, continuous short-term smoking abstinence among 200 smokers enrolled in a cohort study. Methods A nonparametric bootstrapping procedure was used to assess mediation. Results Health locus of control-chance mediated relations between neighborhood vigilance and smoking abstinence in analyses adjusted for sociodemographics and tobacco dependence (p < .05). Greater vigilance was associated with greater attributions that health was affected by chance, which was associated with a lower likelihood of smoking abstinence. Conclusions Results suggest that neighborhood perceptions influence residents’ attributions for health outcomes, which can affect smoking abstinence. PMID:23985180

  12. Between-gender differences in vigilance do not necessarily lead to differences in foraging-vigilance tradeoffs.

    PubMed

    Barnier, Florian; Duncan, Patrick; Fritz, Hervé; Blanchard, Pierrick; Rubenstein, Daniel I; Pays, Olivier

    2016-07-01

    When prey are time limited in their access to food, any trade-off involving time should ultimately affect their intake rate. In many herbivores, males and females experience different ecological pressures affecting their survival and reproduction because of differences in morphology, physiology and energy/nutrient requirements. If males and females have different vigilance strategies that affect their intake rates differently, they will suffer different foraging costs. This is particularly relevant in sexually monomorphic herbivores, where the two sexes have similar basal energy/nutrient requirements and risk of predation. We investigated how gender, reproductive status, age, group size, predation risk, and food biomass affected vigilance, intake rate, and their trade-off in a monomorphic species, the plains zebra (Equus quagga). Males were more vigilant than females, and lactating females were less vigilant than other females; the levels of vigilance were low (ca. 10 % of feeding time). The effects on time spent feeding, bite rates and intake rates were small and statistically not significant. Reproductive status did not affect the strength of the relationship between vigilance and intake rate, but intake rates increased with group size and, for adult females, were higher in tall grass. While gender and reproductive status were major drivers of vigilance, and group size and food biomass of the rate of food intake, males and females adjust their bite rates and food intake with vigilance in similar ways. Our results support the hypothesis that in monomorphic animals, males and females seem to make similar trade-offs (i.e. adjustments) between vigilance and intake rate. PMID:27017605

  13. Warfarin and Drug Interactions: Prescribing Vigilance.

    PubMed

    Hook, J; Millsopp, Lynne; Field, E Anne

    2016-01-01

    A patient taking warfarin presented to the Oral Medicine Clinic at Liverpool University Dental Hospital, having been prescribed metronidazole and miconazole by his general dental practitioner (GDP) for his oral mucosal problem. He subsequently developed bruising on his torso following mild trauma. Having read the drug information leaflet provided with his metronidazole and miconazole, he noted the potential drug interactions between these and warfarin. He therefore stopped his warfarin. The details of this case are outlined, and the potential for significant drug interactions with warfarin are highlighted. The need for dental practitioners to be vigilant concerning drug interactions is emphasized, together with the importance of CPD in relation to drug prescribing. CPD/CLINICAL RELEVANCE: This case report, which is of relevance to all dental practitioners, highlights the importance of up-to-date medical and drug histories and the continuing awareness of potential drug interactions. In this case, patient intervention after checking drug information leaflets prevented serious consequences. The importance and potentially serious consequences of significant drug interactions needs to be understood. PMID:27024900

  14. Noise pollution has limited effects on nocturnal vigilance in peahens

    PubMed Central

    Hermann, Fredrick S.

    2016-01-01

    Natural environments are increasingly exposed to high levels of noise pollution. Noise pollution can alter the behavior of animals but we know little about its effects on antipredator behavior. We therefore investigated the impact of noise pollution on vigilance behavior and roost selection in an avian species, peafowl (Pavo cristatus), that inhabits urban environments. Captive peahens were exposed to noise pollution at night and their vigilance levels and roost selections were monitored. The vigilance levels of peahens were unaffected by exposure to noise pollution within trials. Furthermore, the peahens exhibited no preference for roosting farther or closer to noise pollution. Interestingly, predators often avoided the experimental area during nights with noise pollution, which could explain why vigilance rates were higher overall during control compared to noise trials. The results suggest that peahens’ perception of risk is not drastically impacted by noise pollution but longer-term studies will be necessary to assess any chronic effects. PMID:27703863

  15. Reinforcement enhances vigilance among children with ADHD: comparisons to typically developing children and to the effects of methylphenidate.

    PubMed

    Bubnik, Michelle G; Hawk, Larry W; Pelham, William E; Waxmonsky, James G; Rosch, Keri S

    2015-01-01

    Sustained attention and reinforcement are posited as causal mechanisms in Attention-Deficit/Hyperactivity Disorder (ADHD), but their interaction has received little empirical study. In two studies, we examined the impact of performance-based reinforcement on sustained attention over time, or vigilance, among 9- to 12-year-old children. Study 1 demonstrated the expected vigilance deficit among children with ADHD (n = 25; 12% female) compared to typically developing (TD) controls (n = 33; 22% female) on a standard continuous performance task (CPT). During a subsequent visit, reinforcement improved attention more among children with ADHD than controls. Study 2 examined the separate and combined effects of reinforcement and acute methylphenidate (MPH) on CPT performance in children with ADHD (n = 19; 21% female). Both reinforcement and MPH enhanced overall target detection and attenuated the vigilance decrement that occurred in no-reinforcement, placebo condition. Cross-study comparisons suggested that the combination of MPH and reinforcement eliminated the vigilance deficit in children with ADHD, normalizing sustained attention. This work highlights the clinically and theoretically interesting intersection of reinforcement and sustained attention.

  16. Slow brain oscillations of sleep, resting state, and vigilance.

    PubMed

    Van Someren, E J W; Van Der Werf, Y D; Roelfsema, P R; Mansvelder, H D; da Silva, F H Lopes

    2011-01-01

    The most important quest of cognitive neuroscience may be to unravel the mechanisms by which the brain selects, links, consolidates, and integrates new information into its neuronal network, while preventing saturation to occur. During the past decade, neuroscientists working within several disciplines have observed an important involvement of the specific types of brain oscillations that occur during sleep--the cortical slow oscillations; during the resting state--the fMRI resting state networks including the default-mode network (DMN); and during task performance--the performance modulations that link as well to modulations in electroencephalography or magnetoencephalography frequency content. Understanding the role of these slow oscillations thus appears to be essential for our fundamental understanding of brain function. Brain activity is characterized by oscillations occurring in spike frequency, field potentials or blood oxygen level-dependent functional magnetic resonance imaging signals. Environmental stimuli, reaching the brain through our senses, activate or inactivate neuronal populations and modulate ongoing activity. The effect they sort is to a large extent determined by the momentary state of the slow endogenous oscillations of the brain. In the absence of sensory input, as is the case during rest or sleep, brain activity does not cease. Rather, its oscillations continue and change with respect to their dominant frequencies and coupling topography. This chapter briefly introduces the topics that will be addressed in this dedicated volume of Progress in Brain Research on slow oscillations and sets the stage for excellent papers discussing their molecular, cellular, network physiological and cognitive performance aspects. Getting to know about slow oscillations is essential for our understanding of plasticity, memory, brain structure from synapse to DMN, cognition, consciousness, and ultimately for our understanding of the mechanisms and functions of

  17. Alcohol and Sleep Restriction Combined Reduces Vigilant Attention, Whereas Sleep Restriction Alone Enhances Distractibility

    PubMed Central

    Lee, James; Manousakis, Jessica; Fielding, Joanne; Anderson, Clare

    2015-01-01

    Study Objectives: Alcohol and sleep loss are leading causes of motor vehicle crashes, whereby attention failure is a core causal factor. Despite a plethora of data describing the effect of alcohol and sleep loss on vigilant attention, little is known about their effect on voluntary and involuntary visual attention processes. Design: Repeated-measures, counterbalanced design. Setting: Controlled laboratory setting. Participants: Sixteen young (18–27 y; M = 21.90 ± 0.60 y) healthy males. Interventions: Participants completed an attention test battery during the afternoon (13:00–14:00) under four counterbalanced conditions: (1) baseline; (2) alcohol (0.05% breath alcohol concentration); (3) sleep restriction (02:00–07:00); and (4) alcohol/sleep restriction combined. This test battery included a Psychomotor Vigilance Task (PVT) as a measure of vigilant attention, and two ocular motor tasks—visually guided and antisaccade—to measure the involuntary and voluntary allocation of visual attention. Measurements and Results: Only the combined condition led to reductions in vigilant attention characterized by slower mean reaction time, fastest 10% responses, and increased number of lapses (P < 0.05) on the PVT. In addition, the combined condition led to a slowing in the voluntary allocation of attention as reflected by increased antisaccade latencies (P < 0.05). Sleep restriction alone however increased both antisaccade inhibitory errors [45.8% errors versus < 28.4% all others; P < 0.001] and the involuntary allocation of attention, as reflected by faster visually guided latencies (177.7 msec versus > 185.0 msec all others) to a peripheral target (P < 0.05). Conclusions: Our data reveal specific signatures for sleep related attention failure: the voluntary allocation of attention is impaired, whereas the involuntary allocation of attention is enhanced. This provides key evidence for the role of distraction in attention failure during sleep loss. Citation: Lee J

  18. Artificial light pollution increases nocturnal vigilance in peahens.

    PubMed

    Yorzinski, Jessica L; Chisholm, Sarah; Byerley, Sydney D; Coy, Jeanee R; Aziz, Aisyah; Wolf, Jamie A; Gnerlich, Amanda C

    2015-01-01

    Artificial light pollution is drastically changing the sensory environments of animals. Even though many animals are now living in these changed environments, the effect light pollution has on animal behavior is poorly understood. We investigated the effect of light pollution on nocturnal vigilance in peahens (Pavo cristatus). Captive peahens were exposed to either artificial lighting or natural lighting at night. We employed a novel method to record their vigilance behavior by attaching accelerometers to their heads and continuously monitoring their large head movements. We found that light pollution significantly increases nocturnal vigilance in peahens. Furthermore, the birds faced a trade-off between vigilance and sleep at night: peahens that were more vigilant spent less time sleeping. Given the choice, peahens preferred to roost away from high levels of artificial lighting but showed no preference for roosting without artificial lighting or with low levels of artificial lighting. Our study demonstrates that light pollution can have a substantial impact on animal behavior that can potentially result in fitness consequences. PMID:26339552

  19. Artificial light pollution increases nocturnal vigilance in peahens

    PubMed Central

    Chisholm, Sarah; Byerley, Sydney D; Coy, Jeanee R.; Aziz, Aisyah; Wolf, Jamie A.; Gnerlich, Amanda C.

    2015-01-01

    Artificial light pollution is drastically changing the sensory environments of animals. Even though many animals are now living in these changed environments, the effect light pollution has on animal behavior is poorly understood. We investigated the effect of light pollution on nocturnal vigilance in peahens (Pavo cristatus). Captive peahens were exposed to either artificial lighting or natural lighting at night. We employed a novel method to record their vigilance behavior by attaching accelerometers to their heads and continuously monitoring their large head movements. We found that light pollution significantly increases nocturnal vigilance in peahens. Furthermore, the birds faced a trade-off between vigilance and sleep at night: peahens that were more vigilant spent less time sleeping. Given the choice, peahens preferred to roost away from high levels of artificial lighting but showed no preference for roosting without artificial lighting or with low levels of artificial lighting. Our study demonstrates that light pollution can have a substantial impact on animal behavior that can potentially result in fitness consequences. PMID:26339552

  20. Artificial light pollution increases nocturnal vigilance in peahens.

    PubMed

    Yorzinski, Jessica L; Chisholm, Sarah; Byerley, Sydney D; Coy, Jeanee R; Aziz, Aisyah; Wolf, Jamie A; Gnerlich, Amanda C

    2015-01-01

    Artificial light pollution is drastically changing the sensory environments of animals. Even though many animals are now living in these changed environments, the effect light pollution has on animal behavior is poorly understood. We investigated the effect of light pollution on nocturnal vigilance in peahens (Pavo cristatus). Captive peahens were exposed to either artificial lighting or natural lighting at night. We employed a novel method to record their vigilance behavior by attaching accelerometers to their heads and continuously monitoring their large head movements. We found that light pollution significantly increases nocturnal vigilance in peahens. Furthermore, the birds faced a trade-off between vigilance and sleep at night: peahens that were more vigilant spent less time sleeping. Given the choice, peahens preferred to roost away from high levels of artificial lighting but showed no preference for roosting without artificial lighting or with low levels of artificial lighting. Our study demonstrates that light pollution can have a substantial impact on animal behavior that can potentially result in fitness consequences.

  1. Vigilant care: An integrative reformulation regarding parental monitoring.

    PubMed

    Omer, Haim; Satran, Shai; Driter, Oren

    2016-04-01

    Parental monitoring was once considered to be the approved way for preventing risk behaviors by children and adolescents. In the last years, however, the concept has been the target of cogent criticism questioning the interpretation of findings which support the traditional view of monitoring. After reviewing the various criticisms and the resulting fragmentation of theory and practice, we propose the model of vigilant care as an integrative solution. Vigilant care is a flexible framework within which parents adjust their level of involvement to the warning signals they detect. By justifying moves to higher levels of vigilance with safety considerations and expressing their duty to do so in a decided but noncontrolling manner, parents legitimize their increased involvement both to the child and to themselves. The model offers a unified solution to the ongoing controversy and generates theoretical hypotheses as well as a practice-oriented research program. PMID:26845385

  2. Classifying Vulnerability to Sleep Deprivation Using Baseline Measures of Psychomotor Vigilance

    PubMed Central

    Patanaik, Amiya; Kwoh, Chee Keong; Chua, Eric C.P.; Gooley, Joshua J.; Chee, Michael W.L.

    2015-01-01

    Objective: To identify measures derived from baseline psychomotor vigilance task (PVT) performance that can reliably predict vulnerability to sleep deprivation. Design: Subjects underwent total sleep deprivation and completed a 10-min PVT every 1–2 h in a controlled laboratory setting. Participants were categorized as vulnerable or resistant to sleep deprivation, based on a median split of lapses that occurred following sleep deprivation. Standard reaction time, drift diffusion model (DDM), and wavelet metrics were derived from PVT response times collected at baseline. A support vector machine model that incorporated maximum relevance and minimum redundancy feature selection and wrapper-based heuristics was used to classify subjects as vulnerable or resistant using rested data. Setting: Two academic sleep laboratories. Participants: Independent samples of 135 (69 women, age 18 to 25 y), and 45 (3 women, age 22 to 32 y) healthy adults. Measurements and Results: In both datasets, DDM measures, number of consecutive reaction times that differ by more than 250 ms, and two wavelet features were selected by the model as features predictive of vulnerability to sleep deprivation. Using the best set of features selected in each dataset, classification accuracy was 77% and 82% using fivefold stratified cross-validation, respectively. Conclusions: Despite differences in experimental conditions across studies, drift diffusion model parameters associated reliably with individual differences in performance during total sleep deprivation. These results demonstrate the utility of drift diffusion modeling of baseline performance in estimating vulnerability to psychomotor vigilance decline following sleep deprivation. Citation: Patanaik A, Kwoh CK, Chua EC, Gooley JJ, Chee MW. Classifying vulnerability to sleep deprivation using baseline measures of psychomotor vigilance. SLEEP 2015;38(5):723–734. PMID:25325482

  3. Dose-response relationship between sleep duration and human psychomotor vigilance and subjective alertness

    NASA Technical Reports Server (NTRS)

    Jewett, M. E.; Dijk, D. J.; Kronauer, R. E.; Dinges, D. F.

    1999-01-01

    Although it has been well documented that sleep is required for human performance and alertness to recover from low levels after prolonged periods of wakefulness, it remains unclear whether they increase in a linear or asymptotic manner during sleep. It has been postulated that there is a relation between the rate of improvement in neurobehavioral functioning and rate of decline of slow-wave sleep and/or slow-wave activity (SWS/SWA) during sleep, but this has not been verified. Thus, a cross-study comparison was conducted in which dose-response curves (DRCs) were constructed for Stanford Sleepiness Scale (SSS) and Psychomotor Vigilance Task (PVT) tests taken at 1000 hours by subjects who had been allowed to sleep 0 hours, 2 hours, 5 hours or 8 hours the previous night. We found that the DRCs to each PVT metric improved in a saturating exponential manner, with recovery rates that were similar [time constant (T) approximately 2.14 hours] for all the metrics. This recovery rate was slightly faster than, though not statistically significantly different from, the reported rate of SWS/SWA decline (T approximately 2.7 hours). The DRC to the SSS improved much more slowly than psychomotor vigilance, so that it could be fit equally well by a linear function (slope = -0.26) or a saturating exponential function (T = 9.09 hours). We conclude that although SWS/SWA, subjective alertness, and a wide variety of psychomotor vigilance metrics may all change asymptotically during sleep, it remains to be determined whether the underlying physiologic processes governing their expression are different.

  4. Motivation in vigilance - A test of the goal-setting hypothesis of the effectiveness of knowledge of results.

    NASA Technical Reports Server (NTRS)

    Warm, J. S.; Riechmann, S. W.; Grasha, A. F.; Seibel, B.

    1973-01-01

    This study tested the prediction, derived from the goal-setting hypothesis, that the facilitating effects of knowledge of results (KR) in a simple vigilance task should be related directly to the level of the performance standard used to regulate KR. Two groups of Ss received dichotomous KR in terms of whether Ss response times (RTs) to signal detections exceeded a high or low standard of performance. The aperiodic offset of a visual signal was the critical event for detection. The vigil was divided into a training phase followed by testing, during which KR was withdrawn. Knowledge of results enhanced performance in both phases. However, the two standards used to regulate feedback contributed little to these effects.

  5. Interactions among social monitoring, anti-predator vigilance and group size in eastern grey kangaroos

    PubMed Central

    Favreau, François-René; Goldizen, Anne W.; Pays, Olivier

    2010-01-01

    Group size is known to affect both the amount of time that prey animals spend in vigilance and the degree to which the vigilance of group members is synchronized. However, the variation in group-size effects reported in the literature is not yet understood. Prey animals exhibit vigilance both to protect themselves against predators and to monitor other group members, and both forms of vigilance presumably influence group-size effects on vigilance. However, our understanding of the patterns of individual investment underlying the time sharing between anti-predator and social vigilance is still limited. We studied patterns of variation in individual vigilance and the synchronization of vigilance with group size in a wild population of eastern grey kangaroos (Macropus giganteus) subject to predation, in particular focusing on peripheral females because we expected that they would exhibit both social and anti-predator vigilance. There was no global effect of group size on individual vigilance. The lack of group-size effect was the result of two compensating effects. The proportion of time individuals spent looking at other group members increased, whereas the proportion of time they spent scanning the environment decreased with group size; as a result, overall vigilance levels did not change with group size. Moreover, a degree of synchrony of vigilance occurred within groups and that degree increased with the proportion of vigilance time peripheral females spent in anti-predator vigilance. Our results highlight the crucial roles of both social and anti-predator components of vigilance in the understanding of the relationship between group size and vigilance, as well as in the synchronization of vigilance among group members. PMID:20219737

  6. Interactions among social monitoring, anti-predator vigilance and group size in eastern grey kangaroos.

    PubMed

    Favreau, François-René; Goldizen, Anne W; Pays, Olivier

    2010-07-01

    Group size is known to affect both the amount of time that prey animals spend in vigilance and the degree to which the vigilance of group members is synchronized. However, the variation in group-size effects reported in the literature is not yet understood. Prey animals exhibit vigilance both to protect themselves against predators and to monitor other group members, and both forms of vigilance presumably influence group-size effects on vigilance. However, our understanding of the patterns of individual investment underlying the time sharing between anti-predator and social vigilance is still limited. We studied patterns of variation in individual vigilance and the synchronization of vigilance with group size in a wild population of eastern grey kangaroos (Macropus giganteus) subject to predation, in particular focusing on peripheral females because we expected that they would exhibit both social and anti-predator vigilance. There was no global effect of group size on individual vigilance. The lack of group-size effect was the result of two compensating effects. The proportion of time individuals spent looking at other group members increased, whereas the proportion of time they spent scanning the environment decreased with group size; as a result, overall vigilance levels did not change with group size. Moreover, a degree of synchrony of vigilance occurred within groups and that degree increased with the proportion of vigilance time peripheral females spent in anti-predator vigilance. Our results highlight the crucial roles of both social and anti-predator components of vigilance in the understanding of the relationship between group size and vigilance, as well as in the synchronization of vigilance among group members.

  7. Real-time performance modelling of a Sustained Attention to Response Task.

    PubMed

    Larue, Grégoire S; Rakotonirainy, Andry; Pettitt, Anthony N

    2010-10-01

    Vigilance declines when exposed to highly predictable and uneventful tasks. Monotonous tasks provide little cognitive and motor stimulation and contribute to human errors. This paper aims to model and detect vigilance decline in real time through participants' reaction times during a monotonous task. A laboratory-based experiment adapting the Sustained Attention to Response Task (SART) is conducted to quantify the effect of monotony on overall performance. Relevant parameters are then used to build a model detecting hypovigilance throughout the experiment. The accuracy of different mathematical models is compared to detect in real time - minute by minute - the lapses in vigilance during the task. It is shown that monotonous tasks can lead to an average decline in performance of 45%. Furthermore, vigilance modelling enables the detection of vigilance decline through reaction times with an accuracy of 72% and a 29% false alarm rate. Bayesian models are identified as a better model to detect lapses in vigilance as compared with neural networks and generalised linear mixed models. This modelling could be used as a framework to detect vigilance decline of any human performing monotonous tasks. STATEMENT OF RELEVANCE: Existing research on monotony is largely entangled with endogenous factors such as sleep deprivation, fatigue and circadian rhythm. This paper uses a Bayesian model to assess the effects of a monotonous task on vigilance in real time. It is shown that the negative effects of monotony on the ability to sustain attention can be mathematically modelled and predicted in real time using surrogate measures, such as reaction times. This allows the modelling of vigilance fluctuations.

  8. Real-time performance modelling of a Sustained Attention to Response Task.

    PubMed

    Larue, Grégoire S; Rakotonirainy, Andry; Pettitt, Anthony N

    2010-10-01

    Vigilance declines when exposed to highly predictable and uneventful tasks. Monotonous tasks provide little cognitive and motor stimulation and contribute to human errors. This paper aims to model and detect vigilance decline in real time through participants' reaction times during a monotonous task. A laboratory-based experiment adapting the Sustained Attention to Response Task (SART) is conducted to quantify the effect of monotony on overall performance. Relevant parameters are then used to build a model detecting hypovigilance throughout the experiment. The accuracy of different mathematical models is compared to detect in real time - minute by minute - the lapses in vigilance during the task. It is shown that monotonous tasks can lead to an average decline in performance of 45%. Furthermore, vigilance modelling enables the detection of vigilance decline through reaction times with an accuracy of 72% and a 29% false alarm rate. Bayesian models are identified as a better model to detect lapses in vigilance as compared with neural networks and generalised linear mixed models. This modelling could be used as a framework to detect vigilance decline of any human performing monotonous tasks. STATEMENT OF RELEVANCE: Existing research on monotony is largely entangled with endogenous factors such as sleep deprivation, fatigue and circadian rhythm. This paper uses a Bayesian model to assess the effects of a monotonous task on vigilance in real time. It is shown that the negative effects of monotony on the ability to sustain attention can be mathematically modelled and predicted in real time using surrogate measures, such as reaction times. This allows the modelling of vigilance fluctuations. PMID:20865604

  9. Task engagement, cerebral blood flow velocity, and diagnostic monitoring for sustained attention.

    PubMed

    Matthews, Gerald; Warm, Joel S; Reinerman-Jones, Lauren E; Langheim, Lisa K; Washburn, David A; Tripp, Lloyd

    2010-06-01

    Loss of vigilance may lead to impaired performance in various applied settings including military operations, transportation, and industrial inspection. Individuals differ considerably in sustained attention, but individual differences in vigilance have proven to be hard to predict. The dependence of vigilance on workload factors is consistent with a resource model of sustained attention. Thus, measures of attentional resource availability may predict the operator's subsequent vigilance performance. In this study, we investigated whether a diagnostic battery of measures of response to a cognitive challenge would predict subsequent sustained attention. Measures that may relate to the mobilization of resources in response to task demands include subjective task engagement and coping, and a novel psychophysiological index, cerebral bloodflow velocity (CBFV). A two-phase design was used. First, participants were exposed to a challenging battery of short tasks that elevated CBFV. Second, participants performed a 36-min vigilance task. Two subgroups of participants performed either a sensory vigilance (N = 187) or a cognitive vigilance (N = 107) task. Measures of task engagement, coping, and CBFV response to the short task battery were compared as predictors of subsequent vigilance. Both subjective and CBFV indices of energization predicted sensory and cognitive vigilance, consistent with resource theory. Structural equation modeling was used to develop a latent factor model of influences on sustained attention. It is concluded that measures of resources, conceptualized as multiple energization processes, are potentially useful for diagnostic monitoring in applied settings. Use of a diagnostic task battery in military and transportation settings is discussed, along with some potential limitations on validity of the diagnostic test.

  10. Teaching Blended Content Analysis and Critically Vigilant Media Consumption

    ERIC Educational Resources Information Center

    Harris, Christopher S.

    2015-01-01

    The semester-long activity described herein uses an integrated instructional approach to media studies to introduce students to the research method of qualitative content analysis and help them become more critically vigilant media consumers. The goal is to increase students' media literacy by guiding them in the design of an exploratory…

  11. Giraffe Stature and Neck Elongation: Vigilance as an Evolutionary Mechanism

    PubMed Central

    Williams, Edgar M.

    2016-01-01

    Giraffe (Giraffa camelopardalis), with their long neck and legs, are unique amongst mammals. How these features evolved is a matter of conjecture. The two leading ideas are the high browse and the sexual-selection hypotheses. While both explain many of the characteristics and the behaviour of giraffe, neither is fully supported by the available evidence. The extended viewing horizon afforded by increased height and a need to maintain horizon vigilance, as a mechanism favouring the evolution of increased height is reviewed. In giraffe, vigilance of predators whilst feeding and drinking are important survival factors, as is the ability to interact with immediate herd members, young and male suitors. The evidence regarding giraffe vigilance behaviour is sparse and suggests that over-vigilance has a negative cost, serving as a distraction to feeding. In woodland savannah, increased height allows giraffe to see further, allowing each giraffe to increase the distance between its neighbours while browsing. Increased height allows the giraffe to see the early approach of predators, as well as bull males. It is postulated that the wider panorama afforded by an increase in height and longer neck has improved survival via allowing giraffe to browse safely over wider areas, decreasing competition within groups and with other herbivores. PMID:27626454

  12. The Co-evolution of Honesty and Strategic Vigilance

    PubMed Central

    Heintz, Christophe; Karabegovic, Mia; Molnar, Andras

    2016-01-01

    We hypothesize that when honesty is not motivated by selfish goals, it reveals social preferences that have evolved for convincing strategically vigilant partners that one is a person worth cooperating with. In particular, we explain how the patterns of dishonest behavior observed in recent experiments can be motivated by preferences for social and self-esteem. These preferences have evolved because they are adaptive in an environment where it is advantageous to be selected as a partner by others and where these others are strategically vigilant: they efficiently evaluate the expected benefit of cooperating with specific partners and attend to their intentions. We specify the adaptive value of strategic vigilance and preferences for social and self-esteem. We argue that evolved preferences for social and self-esteem are satisfied by applying mechanisms of strategic vigilance to one's own behavior. We further argue that such cognitive processes obviate the need for the evolution of preferences for fairness and social norm compliance. PMID:27790162

  13. Giraffe Stature and Neck Elongation: Vigilance as an Evolutionary Mechanism.

    PubMed

    Williams, Edgar M

    2016-01-01

    Giraffe (Giraffa camelopardalis), with their long neck and legs, are unique amongst mammals. How these features evolved is a matter of conjecture. The two leading ideas are the high browse and the sexual-selection hypotheses. While both explain many of the characteristics and the behaviour of giraffe, neither is fully supported by the available evidence. The extended viewing horizon afforded by increased height and a need to maintain horizon vigilance, as a mechanism favouring the evolution of increased height is reviewed. In giraffe, vigilance of predators whilst feeding and drinking are important survival factors, as is the ability to interact with immediate herd members, young and male suitors. The evidence regarding giraffe vigilance behaviour is sparse and suggests that over-vigilance has a negative cost, serving as a distraction to feeding. In woodland savannah, increased height allows giraffe to see further, allowing each giraffe to increase the distance between its neighbours while browsing. Increased height allows the giraffe to see the early approach of predators, as well as bull males. It is postulated that the wider panorama afforded by an increase in height and longer neck has improved survival via allowing giraffe to browse safely over wider areas, decreasing competition within groups and with other herbivores. PMID:27626454

  14. Dose-dependent model of caffeine effects on human vigilance during total sleep deprivation.

    PubMed

    Ramakrishnan, Sridhar; Laxminarayan, Srinivas; Wesensten, Nancy J; Kamimori, Gary H; Balkin, Thomas J; Reifman, Jaques

    2014-10-01

    Caffeine is the most widely consumed stimulant to counter sleep-loss effects. While the pharmacokinetics of caffeine in the body is well-understood, its alertness-restoring effects are still not well characterized. In fact, mathematical models capable of predicting the effects of varying doses of caffeine on objective measures of vigilance are not available. In this paper, we describe a phenomenological model of the dose-dependent effects of caffeine on psychomotor vigilance task (PVT) performance of sleep-deprived subjects. We used the two-process model of sleep regulation to quantify performance during sleep loss in the absence of caffeine and a dose-dependent multiplier factor derived from the Hill equation to model the effects of single and repeated caffeine doses. We developed and validated the model fits and predictions on PVT lapse (number of reaction times exceeding 500 ms) data from two separate laboratory studies. At the population-average level, the model captured the effects of a range of caffeine doses (50-300 mg), yielding up to a 90% improvement over the two-process model. Individual-specific caffeine models, on average, predicted the effects up to 23% better than population-average caffeine models. The proposed model serves as a useful tool for predicting the dose-dependent effects of caffeine on the PVT performance of sleep-deprived subjects and, therefore, can be used for determining caffeine doses that optimize the timing and duration of peak performance.

  15. [Patient identification vigilance in public healthcare organizations: inventory in French hospitals and proposals].

    PubMed

    Perrin, A; Morin, C

    2009-01-01

    Utilization of patients databases by the different healthcare departments, technical teams and registration clerks in care centers is becoming more and more important. Patients data exchanges within and between centers are growing, including public and private structures networks and require a complete match of the patient identification data. Because clinical chemists and pathologists are deeply involved in these exchanges, the National Clinical Chemistry College designed a survey about french hospitals practices (2007 july-2008 august) in order to secure patients identification at any stage of their stay. "Identity vigilance" term tends to emerge for designating this new risk management field. The responses from 94 hospitals are analyzed, which demonstrate an heterogeneous implementation and a very unequal concern of this issue in the different sites; 18% have not yet initiated any action. A strong involvement of the pathologists in the applying of identification safety procedures is expressed by their presence in the three executive, operative and underling levels in more than half of sites (in 84% of the sites for the operative level). Only 17% of the pathologists consider the patients database of their hospital software to be of good quality. This survey leads to become aware of local and national tasks that have to be implemented or carried on, both for identity registration at admission and identity checking before any health care. This effort has to be supported by an essential institutionalization of identity vigilance.

  16. Dose-dependent model of caffeine effects on human vigilance during total sleep deprivation.

    PubMed

    Ramakrishnan, Sridhar; Laxminarayan, Srinivas; Wesensten, Nancy J; Kamimori, Gary H; Balkin, Thomas J; Reifman, Jaques

    2014-10-01

    Caffeine is the most widely consumed stimulant to counter sleep-loss effects. While the pharmacokinetics of caffeine in the body is well-understood, its alertness-restoring effects are still not well characterized. In fact, mathematical models capable of predicting the effects of varying doses of caffeine on objective measures of vigilance are not available. In this paper, we describe a phenomenological model of the dose-dependent effects of caffeine on psychomotor vigilance task (PVT) performance of sleep-deprived subjects. We used the two-process model of sleep regulation to quantify performance during sleep loss in the absence of caffeine and a dose-dependent multiplier factor derived from the Hill equation to model the effects of single and repeated caffeine doses. We developed and validated the model fits and predictions on PVT lapse (number of reaction times exceeding 500 ms) data from two separate laboratory studies. At the population-average level, the model captured the effects of a range of caffeine doses (50-300 mg), yielding up to a 90% improvement over the two-process model. Individual-specific caffeine models, on average, predicted the effects up to 23% better than population-average caffeine models. The proposed model serves as a useful tool for predicting the dose-dependent effects of caffeine on the PVT performance of sleep-deprived subjects and, therefore, can be used for determining caffeine doses that optimize the timing and duration of peak performance. PMID:24859426

  17. White-Tailed Deer Vigilance: The Influence of Social and Environmental Factors

    PubMed Central

    Lashley, Marcus A; Chitwood, M. Colter; Biggerstaff, Michael T.; Morina, Daniel L.; Moorman, Christopher E.; DePerno, Christopher S.

    2014-01-01

    Vigilance behavior may directly affect fitness of prey animals, and understanding factors influencing vigilance may provide important insight into predator-prey interactions. We used 40,540 pictures taken withcamera traps in August 2011 and 2012to evaluate factors influencing individual vigilance behavior of white-tailed deer (Odocoileus virginianus) while foraging at baited sites. We used binary logistic regression to determine if individual vigilance was affected by age, sex, and group size. Additionally, we evaluated whether the time of the day,moon phase,and presence of other non-predatorwildlife species impacted individual vigilance. Juveniles were 11% less vigilant at baited sites than adults. Females were 46% more vigilant when fawns were present. Males and females spent more time feeding as group size increased, but with each addition of 1 individual to a group, males increased feeding time by nearly double that of females. Individual vigilance fluctuated with time of day andwith moon phase but generally was least during diurnal and moonlit nocturnal hours, indicating deer have the ability to adjust vigilance behavior to changing predation risk associated with varyinglight intensity.White-tailed deer increased individual vigilance when other non-predator wildlife were present. Our data indicate that differential effects of environmental and social constraints on vigilance behavior between sexes may encourage sexual segregation in white-tailed deer. PMID:24599090

  18. Impaired conflict resolution and vigilance in euthymic bipolar disorder.

    PubMed

    Marotta, Andrea; Chiaie, Roberto Delle; Spagna, Alfredo; Bernabei, Laura; Sciarretta, Martina; Roca, Javier; Biondi, Massimo; Casagrande, Maria

    2015-09-30

    Difficulty attending is a common deficit of euthymic bipolar patients. However, it is not known whether this is a global attentional deficit or relates to a specific attentional network. According to the attention network approach, attention is best understood in terms of three functionally and neuroanatomically distinct networks-alerting, orienting, and executive control. In this study, we explored whether and which of the three attentional networks are altered in euthymic Bipolar Disorder (BD). A sample of euthymic BD patients and age-matched healthy controls completed the Attention Network Test for Interactions and Vigilance (ANTI-V) that provided not only a measure of orienting, executive, and alerting networks, but also an independent measure of vigilance (tonic alerting). Compared to healthy controls, BD patients have impaired executive control (greater interference), reduced vigilance (as indexed by a decrease in the d' sensitivity) as well as slower overall reaction times and poorer accuracy. Our results show that deficits in executive attention and sustained attention often persist in BD patients even after complete remission of affective symptoms, thus suggesting that cognitive enhancing treatments programmed to improve these deficits could contribute to improve their functional recovery.

  19. Impaired conflict resolution and vigilance in euthymic bipolar disorder.

    PubMed

    Marotta, Andrea; Chiaie, Roberto Delle; Spagna, Alfredo; Bernabei, Laura; Sciarretta, Martina; Roca, Javier; Biondi, Massimo; Casagrande, Maria

    2015-09-30

    Difficulty attending is a common deficit of euthymic bipolar patients. However, it is not known whether this is a global attentional deficit or relates to a specific attentional network. According to the attention network approach, attention is best understood in terms of three functionally and neuroanatomically distinct networks-alerting, orienting, and executive control. In this study, we explored whether and which of the three attentional networks are altered in euthymic Bipolar Disorder (BD). A sample of euthymic BD patients and age-matched healthy controls completed the Attention Network Test for Interactions and Vigilance (ANTI-V) that provided not only a measure of orienting, executive, and alerting networks, but also an independent measure of vigilance (tonic alerting). Compared to healthy controls, BD patients have impaired executive control (greater interference), reduced vigilance (as indexed by a decrease in the d' sensitivity) as well as slower overall reaction times and poorer accuracy. Our results show that deficits in executive attention and sustained attention often persist in BD patients even after complete remission of affective symptoms, thus suggesting that cognitive enhancing treatments programmed to improve these deficits could contribute to improve their functional recovery. PMID:26144587

  20. Coordination and synchronisation of anti-predation vigilance in two crane species.

    PubMed

    Ge, Chen; Beauchamp, Guy; Li, Zhongqiu

    2011-01-01

    Much of the previous research on anti-predation vigilance in groups has assumed independent scanning for threats among group members. Alternative patterns that are based on monitoring the vigilance levels of companions can also be adaptive. Coordination of vigilance, in which foragers avoid scanning at the same time as others, should decrease the odds that no group member is alert. Synchronisation of vigilance implies that individuals are more likely to be vigilant when companions are already vigilant. While synchronisation will increase the odds that no one is vigilant, it may allow a better assessment of potential threats. We investigated temporal sequences of vigilance in family flocks consisting of two parents and at most two juveniles in two species of cranes in coastal China. We established whether the observed probability that at least one parent is alert was greater (coordination) or lower (synchronisation) than that predicted under the null hypothesis of independent vigilance. We documented coordination of vigilance in common cranes (Grus grus) foraging in an area with high potential for disturbance by people. We documented synchronisation of vigilance in red-crowned cranes (Grus japonensis) in the less but not in the more disturbed area. Coordination in small flocks leads to high collective vigilance but low foraging rates that may not be suitable in areas with low disturbance. We also argue that synchronisation should break down in areas with high disturbance because periods with low vigilance are riskier. Results highlight the view that temporal patterns of vigilance can take many forms depending on ecological factors. PMID:22028880

  1. Measures and Interpretations of Vigilance Performance: Evidence Against the Detection Criterion

    NASA Technical Reports Server (NTRS)

    Balakrishnan, J. D.

    1998-01-01

    Operators' performance in a vigilance task is often assumed to depend on their choice of a detection criterion. When the signal rate is low this criterion is set high, causing the hit and false alarm rates to be low. With increasing time on task the criterion presumably tends to increase even further, thereby further decreasing the hit and false alarm rates. Virtually all of the empirical evidence for this simple interpretation is based on estimates of the bias measure Beta from signal detection theory. In this article, I describe a new approach to studying decision making that does not require the technical assumptions of signal detection theory. The results of this new analysis suggest that the detection criterion is never biased toward either response, even when the signal rate is low and the time on task is long. Two modifications of the signal detection theory framework are considered to account for this seemingly paradoxical result. The first assumes that the signal rate affects the relative sizes of the variances of the information distributions; the second assumes that the signal rate affects the logic of the operator's stopping rule. Actual or potential applications of this research include the improved training and performance assessment of operators in areas such as product quality control, air traffic control, and medical and clinical diagnosis.

  2. [Adaptation of vigilance behavior in ex situ conservation of Tibetan antelope].

    PubMed

    Sun, Ping; Yu, Hong-Hao; Zhao, Xin-Quan; Wang, De-Hua

    2011-10-01

    Tibetan antelope (Pantholops hodgsoni) are an endemic and endangered species of the Tibetan Plateau. Ex situ conservation may represent an important way to protect Tibetan antelope; however, this process may influence aspects of their behavior. To investigate the ability of these antelopes to adapt to new environments, a study on the vigilance behavior of captive antelope in different seasons was conducted. Using instantaneous scan sampling, focal animal sampling, and all-occurrence recording methods, the vigilance rate and vigilance time of captive male and female Tibetan antelope during cold and warm seasons were recorded and analyzed. Very significant sex differences in vigilance behavior were observed during the warm season, but were not observed in the cold season. Interestingly, vigilance behavior showed seasonal variation as there were significant differences in vigilance time and vigilance rate between cold and warm seasons in both males and females. Specifically, males and females showed more vigilance during the cold than warm season. No interaction between season and sex was found in the vigilance behavior of antelope. Comparing vigilance behavioral characteristic with the Kekexili Tibetan antelope indicated that captive antelope could adapt to a new environment.

  3. Influence of the composition of a meal taken after physical exercise on mood, vigilance, performance.

    PubMed

    Verger, P; Lagarde, D; Batejat, D; Maitre, J F

    1998-06-01

    The metabolic and behavioral effects of nutrients after exercise on vigilance level, performance, and mood have been minimally studied and have given contradictory results. In order to increase the understanding of the relationships between nutrition, exercise and performance, this experiment compared the effects on mood and performance of a protein- rich meal and a protein- poor meal, eaten just after an acute session of exercise. Vigilance and mood were evaluated by visual analog scales, and memory was measured by memory search task from the AGARD STRES battery, based on the Sternberg paradigm. Forty-two subjects were involved in this experiment. All subjects participated in the study of the effect of exercise after two kinds of meals (protein and nonprotein). Two groups of fourteen subjects we used to evaluate the effect of the exercise and the effect of the delay of meal intake after exercise in the two kinds of diet. The results show no difference in memory performance between exercise and rest conditions, nor between "protein" and "no protein" meal groups. They do show, however, that subjects feel happier after a meal with protein than after a meal without protein. The effects of the "no protein" meal on drowsiness differ with the glucide content of the meal. Subjects are less drowsy when they eat between 125 and 150 g of glucide than when they eat more than 150 g. The rousing effect induced by physical exercise is counterbalanced when subjects eat more than 150 g of carbohydrate. The anxiolytic effect of glucide is re-established.

  4. Effects of parental vigilant care and feedback on novice driver risk.

    PubMed

    Shimshoni, Yaara; Farah, Haneen; Lotan, Tsippy; Grimberg, Einat; Dritter, Oren; Musicant, Oren; Toledo, Tomer; Omer, Haim

    2015-01-01

    Vigilant care aims at reducing adolescent risk behaviors while matching parental involvement to the level of alarm signs. This study examined the effect of parent training in vigilant care and technological feedback on driving risk of novice male drivers. A sample of 217 Israeli families was divided into four conditions: a) no-feedback, b) individual feedback, c) family feedback, and d) family feedback plus parent training in vigilant care. Feedback and risk assessment were conducted through in-vehicle data recorders. A significant difference was found in favor of the vigilant care group compared to the no feedback group. When only the drivers in the high risk percentiles were considered, the vigilant care group was found superior to the family feedback group. The findings suggest that parental training in vigilant care may help reduce driving risk.

  5. Vigilance and feeding behaviour in large feeding flocks of laughing gulls, Larus atricilla, on Delaware Bay

    NASA Astrophysics Data System (ADS)

    Burger, Joanna; Gochfeld, Michael

    1991-02-01

    Laughing gulls ( Larus atricilla) forage on horseshoe crab ( Limulus polyphemus) eggs during May in Delaware Bay each year. They feed in dense flocks, and foraging rates vary with vigilance, bird density, number of steps and location in the flock, whereas time devoted to vigilance is explained by number of steps, density, location and feeding rates. The time devoted to vigilance decreases with increasing density, increasing foraging rates and decreasing aggression. Birds foraging on the edge of flocks take fewer pecks and more steps, and devote more time to vigilance than those in the intermediate or central parts of a flock.

  6. The effects of nicotine dose expectancy and motivationally relevant distracters on vigilance.

    PubMed

    Robinson, Jason D; Engelmann, Jeffery M; Cui, Yong; Versace, Francesco; Waters, Andrew J; Gilbert, David G; Gritz, Ellen R; Cinciripini, Paul M

    2014-09-01

    The imminence of drug use (i.e., drug availability) has been found to be related to intensity of drug craving, but its effects on attentional bias to drug cues are unclear. This study investigated the effects of nicotine availability on attentional bias to smoking, affective, and neutral cues in a sample of adult smokers during a vigilance task. At the beginning of each of 4 laboratory sessions, overnight nicotine-deprived smokers (n = 51) were instructed that they would smoke a cigarette containing either nicotine (Told-NIC) or no nicotine (Told-DENIC) after completing the rapid visual information processing task with central emotional distracters (RVIP-CED). The RVIP-CED presented digits at a rapid pace, with participants instructed to respond with button presses to every third consecutive even or odd digit. Some digits were preceded by smoking, pleasant, unpleasant, or neutral distracter slides. During Told-NIC conditions, participants produced significantly longer reaction time (RT) latency than during Told-DENIC conditions. RT sensitivity (d'), a measure of the ability to discriminate true positives from false positives, was significantly lower during the Told-NIC than during the Told-DENIC conditions to targets following cigarette distracters. These results suggest that nicotine-deprived smokers expecting to imminently smoke a cigarette experience greater distraction, particularly to smoking-related stimuli, than when expecting to smoke a denicotinized cigarette.

  7. Sleep and vigilance linked to melanism in wild barn owls.

    PubMed

    Scriba, M F; Rattenborg, N C; Dreiss, A N; Vyssotski, A L; Roulin, A

    2014-10-01

    Understanding the function of variation in sleep requires studies in the natural ecological conditions in which sleep evolved. Sleep has an impact on individual performance and hence may integrate the costs and benefits of investing in processes that are sensitive to sleep, such as immunity or coping with stress. Because dark and pale melanic animals differentially regulate energy homeostasis, immunity and stress hormone levels, the amount and/or organization of sleep may covary with melanin-based colour. We show here that wild, cross-fostered nestling barn owls (Tyto alba) born from mothers displaying more black spots had shorter non-REM (rapid eye movement) sleep bouts, a shorter latency until the occurrence of REM sleep after a bout of wakefulness and more wakefulness bouts. In male nestlings, the same sleep traits also correlated with their own level of spotting. Because heavily spotted male nestlings and the offspring of heavily spotted biological mothers switched sleep-wakefulness states more frequently, we propose the hypothesis that they could be also behaviourally more vigilant. Accordingly, nestlings from mothers displaying many black spots looked more often towards the nest entrance where their parents bring food and towards their sibling against whom they compete. Owlets from heavily spotted mothers might invest more in vigilance, thereby possibly increasing associated costs due to sleep fragmentation. We conclude that different strategies of the regulation of brain activity have evolved and are correlated with melanin-based coloration.

  8. Sleep and vigilance linked to melanism in wild barn owls.

    PubMed

    Scriba, M F; Rattenborg, N C; Dreiss, A N; Vyssotski, A L; Roulin, A

    2014-10-01

    Understanding the function of variation in sleep requires studies in the natural ecological conditions in which sleep evolved. Sleep has an impact on individual performance and hence may integrate the costs and benefits of investing in processes that are sensitive to sleep, such as immunity or coping with stress. Because dark and pale melanic animals differentially regulate energy homeostasis, immunity and stress hormone levels, the amount and/or organization of sleep may covary with melanin-based colour. We show here that wild, cross-fostered nestling barn owls (Tyto alba) born from mothers displaying more black spots had shorter non-REM (rapid eye movement) sleep bouts, a shorter latency until the occurrence of REM sleep after a bout of wakefulness and more wakefulness bouts. In male nestlings, the same sleep traits also correlated with their own level of spotting. Because heavily spotted male nestlings and the offspring of heavily spotted biological mothers switched sleep-wakefulness states more frequently, we propose the hypothesis that they could be also behaviourally more vigilant. Accordingly, nestlings from mothers displaying many black spots looked more often towards the nest entrance where their parents bring food and towards their sibling against whom they compete. Owlets from heavily spotted mothers might invest more in vigilance, thereby possibly increasing associated costs due to sleep fragmentation. We conclude that different strategies of the regulation of brain activity have evolved and are correlated with melanin-based coloration. PMID:25056556

  9. The EUROCET Network: Support for Coding, Vigilance and Surveillance

    PubMed Central

    Mareri, Maura; Filippetti, Marzia; Ghirardini, Angelo; Vespasiano, Francesca; Ciaccio, Paola Di; Nanni Costa, Alessandro

    2011-01-01

    Background In the last years, there have been increasing concerns about the safety and traceability of human tissues and cells in Europe. In order to regulate this part of medical practice, the European Commission issued 3 directives between 2004 and 2006 and endorsed EUROCET to support member states in fulfilling some of their obligations. Mathods EUROCET created a connection with the European Union (EU) Competent Authorities (CAs) and set up a website where lists of the CAs, the authorized Tissue Establishments (TEs) and the activity data are published and updated. Moreover, EUROCET is involved within the Vigilance and Surveillance of Substances of Human Origin (SOHO V&S) project, aiming to support the EU member states in the establishment of vigilance and surveillance systems for tissues and cells. EUROCET is also working with EU stakeholders to develop a common coding system concerning donation and products. Results There are 33 countries in EUROCET and 57 CAs. 3,974 TEs are recorded: 1,108 for tissues, 1,480 for haematopoietic progenitor cells and 1,386 for assisted reproduction. On the website, it is possible to find the 2010 activity data report. Conclusion Based on its cooperation with the CAs, EUROCET represents them in the European network. Nowadays, the EU member states can rely on a web portal and database in order to put the tissue and cell directives into practice. PMID:22403518

  10. [Allergic risk and role of the Allergy Vigilance Network].

    PubMed

    Moneret-Vautrin, Denise-Anne

    2007-01-01

    The recent increase in the incidence of severe anaphylaxis calls for continual assessment of risk factor and dangers associated with food allergy, keeping abreast of changes in the food industry. Allergologists, regulatory bodies and the food industry are all responsible for food safety. The Allergy Vigilance Network, founded by a university research team and comprising 398 French and Belgian allergologists, has developed a three-point strategy. First, reporting cases of severe anaphylaxis of document allergic origin makes it possible to monitor the prevalence of food allergens and to evaluate the quality of management of allergy-related emergencies, thus providing data suitable for estimating the economic burden of anaphylaxis. The second objective of the network is to set up multicenter trials to determine the prevalence of sensitization to risk allergens, such as peanut, lupin and plant pollen, of which transgenic varieties will soon emerge. The third objective is screening and long-term monitoring of dangers related to new foods, ingredients and adjuvant sensitizing factors. Post-marketing monitoring of potential allergic risks arising from genetically modified food is another aim of the network, together with the establishment of a serum bank, following WHO/FAO recommendations. The Allergy Vigilance Network, together with the French National Institute for Food Safety (AFSSA), the Ministry of Consumer Affairs (DGCCRF) and various patient associations, is striving to analyse and deal with dangers related to the allergenicity of natural and modified food proteins.

  11. Fitness for duty: A 3 minute version of the Psychomotor Vigilance Test predicts fatigue related declines in luggage screening performance

    PubMed Central

    Basner, Mathias; Rubinstein, Joshua

    2011-01-01

    Objective To evaluate the ability of a 3-min Psychomotor Vigilance Test (PVT) to predict fatigue related performance decrements on a simulated luggage screening task (SLST). Methods Thirty-six healthy non-professional subjects (mean age 30.8 years, 20 female) participated in a 4 day laboratory protocol including a 34 hour period of total sleep deprivation with PVT and SLST testing every 2 hours. Results Eleven and 20 lapses (355 ms threshold) on the PVT optimally divided SLST performance into high, medium, and low performance bouts with significantly decreasing threat detection performance A′. Assignment to the different SLST performance groups replicated homeostatic and circadian patterns during total sleep deprivation. Conclusions The 3 min PVT was able to predict performance on a simulated luggage screening task. Fitness-for-duty feasibility should now be tested in professional screeners and operational environments. PMID:21912278

  12. Effects of Reproductive Status, Social Rank, Sex and Group Size on Vigilance Patterns in Przewalski's Gazelle

    PubMed Central

    Li, Chunlin; Jiang, Zhigang; Li, Linlin; Li, Zhongqiu; Fang, Hongxia; Li, Chunwang; Beauchamp, Guy

    2012-01-01

    Background Quantifying vigilance and exploring the underlying mechanisms has been the subject of numerous studies. Less attention has focused on the complex interplay between contributing factors such as reproductive status, social rank, sex and group size. Reproductive status and social rank are of particular interest due to their association with mating behavior. Mating activities in rutting season may interfere with typical patterns of vigilance and possibly interact with social rank. In addition, balancing the tradeoff between vigilance and life maintenance may represent a challenge for gregarious ungulate species rutting under harsh winter conditions. We studied vigilance patterns in the endangered Przewalski's gazelle (Procapra przewalskii) during both the rutting and non-rutting seasons to examine these issues. Methodology/Principal Findings Field observations were carried out with focal sampling during rutting and non-rutting season in 2008–2009. Results indicated a complex interplay between reproductive status, social rank, sex and group size in determining vigilance in this species. Vigilance decreased with group size in female but not in male gazelles. Males scanned more frequently and thus spent more time vigilant than females. Compared to non-rutting season, gazelles increased time spent scanning at the expense of bedding in rutting season. During the rutting season, territorial males spent a large proportion of time on rutting activities and were less vigilant than non-territorial males. Although territorial males may share collective risk detection with harem females, we suggest that they are probably more vulnerable to predation because they seemed reluctant to leave rut stands under threats. Conclusions/Significance Vigilance behavior in Przewalski's gazelle was significantly affected by reproductive status, social rank, sex, group size and their complex interactions. These findings shed light on the mechanisms underlying vigilance patterns and

  13. The amplitude of the resting-state fMRI global signal is related to EEG vigilance measures

    PubMed Central

    Wong, Chi Wah; Olafsson, Valur; Tal, Omer; Liu, Thomas T.

    2013-01-01

    In resting-state functional magnetic resonance imaging (fMRI), functional connectivity measures can be influenced by the presence of a strong global component. A widely used pre-processing method for reducing the contribution of this component is global signal regression, in which a global mean time series signal is projected out of the fMRI time series data prior to the computation of connectivity measures. However, the use of global signal regression is controversial because the method can bias the correlation values to have an approximately zero mean and may in some instances create artifactual negative correlations. In addition, while many studies treat the global signal as a non-neural confound that needs to be removed, evidence from electrophysiological and fMRI measures in primates suggests that the global signal may contain significant neural correlates. In this study, we used simultaneously acquired fMRI and electroencephalographic (EEG) measures of resting-state activity to assess the relation between the fMRI global signal and EEG measures of vigilance in humans. We found that the amplitude of the global signal (defined as the standard deviation of the global signal) exhibited a significant negative correlation with EEG vigilance across subjects studied in the eyes-closed condition. In addition, increases in EEG vigilance due to the ingestion of caffeine were significantly associated with both a decrease in global signal amplitude and an increase in the average level of anti-correlation between the default mode network and the task-positive network. PMID:23899724

  14. Vigilance of kit foxes at water sources: a test of competing hypotheses for a solitary carnivore subject to predation.

    PubMed

    Hall, Lucas K; Day, Casey C; Westover, Matthew D; Edgel, Robert J; Larsen, Randy T; Knight, Robert N; McMillan, Brock R

    2013-03-01

    Animals that are potential prey do not respond equally to direct and indirect cues related to risk of predation. Based on differential responses to cues, three hypotheses have been proposed to explain spatial variation in vigilance behavior. The predator-vigilance hypothesis proposes that prey increase vigilance where there is evidence of predators. The visibility-vigilance hypothesis suggests that prey increase vigilance where visibility is obstructed. Alternatively, the refuge-vigilance hypothesis proposes that prey may perceive areas with low visibility (greater cover) as refuges and decrease vigilance. We evaluated support for these hypotheses using the kit fox (Vulpes macrotis), a solitary carnivore subject to intraguild predation, as a model. From 2010 to 2012, we used infrared-triggered cameras to record video of kit fox behavior at water sources in Utah, USA. The refuge-vigilance hypothesis explained more variation in vigilance behavior of kit foxes than the other two hypotheses (AICc model weight=0.37). Kit foxes were less vigilant at water sources with low overhead cover (refuge) obstructing visibility. Based on our results, the predator-vigilance and visibility-vigilance hypotheses may not be applicable to all species of prey. Solitary prey, unlike gregarious prey, may use areas with concealing cover to maximize resource acquisition and minimize vigilance.

  15. In Search of Vigilance: The Problem of Iatrogenically Created Psychological Phenomena

    ERIC Educational Resources Information Center

    Hancock, P. A.

    2013-01-01

    To what extent are identified psychological processes created in laboratories? The present work addresses this issue with reference to one particular realm of behavior: vigilance. Specifically, I argue that the classic vigilance decrement function can be viewed more realistically and advantageously as an "invigilant" increment function. Rather…

  16. Vigilance and Avoidance of Threat in the Eye Movements of Children with Separation Anxiety Disorder

    ERIC Educational Resources Information Center

    In-Albon, Tina; Kossowsky, Joe; Schneider, Silvia

    2010-01-01

    The "vigilance-avoidance" attention pattern is found in anxious adults, who initially gaze more at threatening pictures than nonanxious adults (vigilance), but subsequently gaze less at them than nonanxious adults (avoidance). The present research, using eye tracking methodology, tested whether anxious children show the same pattern. Children with…

  17. Attention/Vigilance in Schizophrenia: Performance Results from a Large Multi-Site Study of the Consortium on the Genetics of Schizophrenia (COGS)

    PubMed Central

    Nuechterlein, Keith H.; Green, Michael F.; Calkins, Monica E.; Greenwood, Tiffany A.; Gur, Raquel E.; Gur, Ruben C.; Lazzeroni, Laura C.; Light, Gregory A.; Radant, Allen D.; Seidman, Larry J.; Siever, Larry J.; Silverman, Jeremy M.; Sprock, Joyce; Stone, William S.; Sugar, Catherine A.; Swerdlow, Neal R.; Tsuang, Debby W.; Tsuang, Ming T.; Turetsky, Bruce I.; Braff, David L.

    2015-01-01

    Attention/vigilance impairments are present in individuals with schizophrenia across psychotic and remitted states and in their first-degree relatives. An important question is whether deficits in attention/vigilance can be consistently and reliably measured across sites varying in many participant demographic, clinical, and functional characteristics, as needed for large-scale genetic studies of endophenotypes. We examined Continuous Performance Test (CPT) data from Phase 2 of the Consortium on the Genetics of Schizophrenia (COGS-2), the largest-scale assessment of cognitive and psychophysiological endophenotypes relevant to schizophrenia. CPT data from 2251 participants from five sites were examined. A perceptual-load vigilance task (the Degraded Stimulus CPT or DS-CPT) and a memory-load vigilance task (CPT - Identical Pairs or CPT-IP) were utilized. Schizophrenia patients performed more poorly than healthy comparison subjects (HCS) across sites, despite significant site differences in participant age, sex, education, and racial distribution. Patient-HCS differences in signal/noise discrimination (d’) in the DS-CPT varied significantly across sites, but averaged a medium effect size. CPT-IP performance showed large patient-HCS differences across sites. Poor CPT performance was independent of or weakly correlated with symptom severity, but was significantly associated with lower educational achievement and functional capacity. Current smoking was associated with poorer CPT-IP d’. Patients taking both atypical and typical antipsychotic medication performed more poorly than those on no or atypical antipsychotic medications, likely reflecting their greater severity of illness. We conclude that CPT deficits in schizophrenia can be reliably detected across sites, are relatively independent of current symptom severity, and are related to functional capacity. PMID:25749017

  18. EDI system definition for a European medical device vigilance system.

    PubMed

    Doukidis, G; Pallikarakis, N; Pangalos, G; Vassilacopoulos, G; Pramataris, K

    1996-01-01

    EDI is expected to be the dominant form of business communication between organizations moving to the Electronic Commerce era of 2000. The healthcare sector is already using EDI in the hospital supply function as well as in the clinical area and the reimbursement process. In this paper, we examine the use of EDI in the healthcare administration sector and more specifically its application to the Medical Device Vigilance System. Firstly, the potential of this approach is examined, followed by the definition of the EDI System Reference Model and the specification of the required system architecture. Each of the architecture's components are then explained in more detail, followed by the most important implementation options relating to them. PMID:9062886

  19. Relapsing Fever: Diagnosis Thanks to a Vigilant Hematology Laboratory.

    PubMed

    Fuchs, Inbal; Tarabin, Salman; Kafka, Michael

    2015-07-01

    Three cases of relapsing fever from southern Israel were diagnosed promptly thanks to vigilance of the hematology laboratory technicians. In this region of Israel, patients presenting with prolonged fever and leukopenia without localizing symptoms are generally suspected of having brucellosis or a rickettsial disease. Pediatric patients with prolonged fever, cytopenias, and negative aforementioned serologies are often hospitalized for further work-up. Because of the policy of performing a manual blood smear when results of the automated blood count demonstrate severe anemia and abnormal platelet and/or white blood cell counts, a diagnosis of tick-borne relapsing fever was confirmed and promptly relayed to the physician. This routine prevented unnecessary examinations and hospitalization days and provided important information to regional epidemiology and public health authorities.

  20. Fast and accurate decisions through collective vigilance in fish shoals

    PubMed Central

    Ward, Ashley J. W.; Herbert-Read, James E.; Sumpter, David J. T.; Krause, Jens

    2011-01-01

    Although it has been suggested that large animal groups should make better decisions than smaller groups, there are few empirical demonstrations of this phenomenon and still fewer explanations of the how these improvements may be made. Here we show that both speed and accuracy of decision making increase with group size in fish shoals under predation threat. We examined two plausible mechanisms for this improvement: first, that groups are guided by a small proportion of high-quality decision makers and, second, that group members use self-organized division of vigilance. Repeated testing of individuals showed no evidence of different decision-making abilities between individual fish. Instead, we suggest that shoals achieve greater decision-making efficiencies through division of labor combined with social information transfer. Our results should prompt reconsideration of how we view cooperation in animal groups with fluid membership. PMID:21262802

  1. Randomized Controlled Trial Comparing Flexible and Continuous Positive Airway Pressure Delivery: Effects on Compliance, Objective and Subjective Sleepiness and Vigilance

    PubMed Central

    Bakker, Jessie; Campbell, Angela; Neill, Alister

    2010-01-01

    Study Objectives: Positive airway pressure (PAP) treatment for obstructive sleep apnea (OSA) can be limited by suboptimal compliance. C-Flex technology (Philips Respironics, PA, USA) reduces pressure during expiration, aiming to improve comfort and therefore compliance. This may be of particular relevance to patients requiring high pressures. Many studies thus far have suffered from design limitations and small sample sizes. This study aimed to compare compliance with C-Flex and CPAP, as well as analyzing objective and subjective sleepiness and vigilance. Design: Three-month, double-blinded, parallel-arm randomized controlled trial. Setting: A university-based sleep laboratory. Patients: 76 consecutive patients with severe OSA (mean ± SD AHI 60.2 ± 32.9 events/hour, ESS 13.6 ± 4.5/24, BMI 35.6 ± 7.8 kg/m2), without significant cardiac, respiratory, psychiatric, or sleep comorbidities. Interventions: Patients were randomized to C-Flex (dip level 2) or CPAP. Measurements and Results: Patients underwent titration with C-Flex/CPAP (mean pressure 11.6 cm H2O). Modified maintenance of wakefulness tests (mod-MWT), psychomotor vigilance tasks (PVT) and questionnaires were administered at baseline and after one and 3 months. Median compliance was 5.51 and 5.89 h/ night in the C-Flex and CPAP groups respectively (P = 0.82). There were no significant differences between groups in terms of PVT reaction time, subjective sleepiness, sleep quality, health-related quality of life, or treatment comfort. There was no significant difference between the groups regarding the change in mod-MWT sleep latency values. Conclusions: In patients with severe OSA both CPAP and C-Flex resulted in substantial improvements in sleepiness, vigilance, and quality of life. The use of C-Flex did not result in greater compliance, and neither treatment appeared superior. Citation: Bakker J; Campbell A; Neill A. Randomized controlled trial comparing flexible and continuous positive airway pressure

  2. The Effects of Social Anxiety and State Anxiety on Visual Attention: Testing the Vigilance-Avoidance Hypothesis.

    PubMed

    Singh, J Suzanne; Capozzoli, Michelle C; Dodd, Michael D; Hope, Debra A

    2015-01-01

    A growing theoretical and research literature suggests that trait and state social anxiety can predict attentional patterns in the presence of emotional stimuli. The current study adds to this literature by examining the effects of state anxiety on visual attention and testing the vigilance-avoidance hypothesis, using a method of continuous visual attentional assessment. Participants were 91 undergraduate college students with high or low trait fear of negative evaluation (FNE), a core aspect of social anxiety, who were randomly assigned to either a high or low state anxiety condition. Participants engaged in a free view task in which pairs of emotional facial stimuli were presented and eye movements were continuously monitored. Overall, participants with high FNE avoided angry stimuli and participants with high state anxiety attended to positive stimuli. Participants with high state anxiety and high FNE were avoidant of angry faces, whereas participants with low state and low FNE exhibited a bias toward angry faces. The study provided partial support for the vigilance-avoidance hypothesis. The findings add to the mixed results in the literature that suggest that both positive and negative emotional stimuli may be important in understanding the complex attention patterns associated with social anxiety. Clinical implications and suggestions for future research are discussed.

  3. Equating tasks and sustaining attention in children and adults: the methodological and theoretical utility of d' matching.

    PubMed

    Laurie-Rose, Cynthia; Bennett-Murphy, Laura; Curtindale, Lori M; Granger, Andrea L; Walker, Heidi B

    2005-02-01

    The present study develops a method to create task equivalency for children and adults in vigilance research. Experiment 1 employed the signal detection index of perceptual sensitivity (d') to calibrate vigilance tasks for 32 children (ages 7-8) and 32 adults. The results of Experiment 1 suggest that task equivalency across groups can be attained, and a vigilance decrement was observed for children. In Experiment 2, the task parameter of event rate was manipulated across two vigils. Again, 32 children (ages 7-8) and 32 adults participated. The results suggest that a reverse event rate effect emerged for both children and adults. In addition, developmental differences in response to the event rate manipulation and with respect to the vigilance decrement emerged: Children benefited less from the manipulation and were more likely to demonstrate a vigilance decrement than were adults. No developmental differences emerged for the sensitivity decrement. The results are explained with reference to how task demands interact with participant arousal, and implications for development and for future research are discussed. PMID:15971689

  4. Maximizing Sensitivity of the Psychomotor Vigilance Test (PVT) to Sleep Loss

    PubMed Central

    Basner, Mathias; Dinges, David F.

    2011-01-01

    Study Objectives: The psychomotor vigilance test (PVT) is among the most widely used measures of behavioral alertness, but there is large variation among published studies in PVT performance outcomes and test durations. To promote standardization of the PVT and increase its sensitivity and specificity to sleep loss, we determined PVT metrics and task durations that optimally discriminated sleep deprived subjects from alert subjects. Design: Repeated-measures experiments involving 10-min PVT assessments every 2 h across both acute total sleep deprivation (TSD) and 5 days of chronic partial sleep deprivation (PSD). Setting: Controlled laboratory environment. Participants: 74 healthy subjects (34 female), aged 22–45 years. Interventions: TSD experiment involving 33 h awake (N = 31 subjects) and a PSD experiment involving 5 nights of 4 h time in bed (N = 43 subjects). Measurements and Results: In a paired t-test paradigm and for both TSD and PSD, effect sizes of 10 different PVT performance outcomes were calculated. Effect sizes were high for both TSD (1.59–1.94) and PSD (0.88–1.21) for PVT metrics related to lapses and to measures of psychomotor speed, i.e., mean 1/RT (response time) and mean slowest 10% 1/RT. In contrast, PVT mean and median RT outcomes scored low to moderate effect sizes influenced by extreme values. Analyses facilitating only portions of the full 10-min PVT indicated that for some outcomes, high effect sizes could be achieved with PVT durations considerably shorter than 10 min, although metrics involving lapses seemed to profit from longer test durations in TSD. Conclusions: Due to their superior conceptual and statistical properties and high sensitivity to sleep deprivation, metrics involving response speed and lapses should be considered primary outcomes for the 10-min PVT. In contrast, PVT mean and median metrics, which are among the most widely used outcomes, should be avoided as primary measures of alertness. Our analyses also suggest

  5. Human disturbances, habitat characteristics and social environment generate sex-specific responses in vigilance of Mediterranean mouflon.

    PubMed

    Benoist, Stéphanie; Garel, Mathieu; Cugnasse, Jean-Marc; Blanchard, Pierrick

    2013-01-01

    In prey species, vigilance is an important part of the decision making process related to predation risk effects. Therefore, understanding the mechanisms shaping vigilance behavior provides relevant insights on factors influencing individual fitness. We investigated the role of extrinsic and intrinsic factors on vigilance behavior in Mediterranean mouflon (Ovis gmelini musimon×Ovis sp.) in a study site spatially and temporally contrasted in human pressures. Both sexes were less vigilant in the wildlife reserve compared to surrounding unprotected areas, except for males during the hunting period. During this period, males tended to be less strictly restricted to the reserve than females what might lead to a pervasive effect of hunting within the protected area, resulting in an increase in male vigilance. It might also be a rutting effect that did not occur in unprotected areas because males vigilance was already maximal in response to human disturbances. In both sexes, yearlings were less vigilant than adults, probably because they traded off vigilance for learning and energy acquisition and/or because they relied on adult experience present in the group. Similarly, non-reproductive females benefited of the vigilance effort provided by reproductive females when belonging to the same group. However, in the absence of reproductive females, non-reproductive females were as vigilant as reproductive females. Increasing group size was only found to reduce vigilance in females (up to 17.5%), not in males. We also showed sex-specific responses to habitat characteristics. Females increased their vigilance when habitat visibility decreased (up to 13.8%) whereas males increased their vigilance when feeding on low quality sites, i.e., when concomitant increase in chewing time can be devoted to vigilance with limited costs. Our global approach was able to disentangle the sex-specific sources of variation in mouflon vigilance and stressed the importance of reserves in managing

  6. Human Disturbances, Habitat Characteristics and Social Environment Generate Sex-Specific Responses in Vigilance of Mediterranean Mouflon

    PubMed Central

    Benoist, Stéphanie; Garel, Mathieu; Cugnasse, Jean-Marc; Blanchard, Pierrick

    2013-01-01

    In prey species, vigilance is an important part of the decision making process related to predation risk effects. Therefore, understanding the mechanisms shaping vigilance behavior provides relevant insights on factors influencing individual fitness. We investigated the role of extrinsic and intrinsic factors on vigilance behavior in Mediterranean mouflon (Ovis gmelini musimon×Ovis sp.) in a study site spatially and temporally contrasted in human pressures. Both sexes were less vigilant in the wildlife reserve compared to surrounding unprotected areas, except for males during the hunting period. During this period, males tended to be less strictly restricted to the reserve than females what might lead to a pervasive effect of hunting within the protected area, resulting in an increase in male vigilance. It might also be a rutting effect that did not occur in unprotected areas because males vigilance was already maximal in response to human disturbances. In both sexes, yearlings were less vigilant than adults, probably because they traded off vigilance for learning and energy acquisition and/or because they relied on adult experience present in the group. Similarly, non-reproductive females benefited of the vigilance effort provided by reproductive females when belonging to the same group. However, in the absence of reproductive females, non-reproductive females were as vigilant as reproductive females. Increasing group size was only found to reduce vigilance in females (up to 17.5%), not in males. We also showed sex-specific responses to habitat characteristics. Females increased their vigilance when habitat visibility decreased (up to 13.8%) whereas males increased their vigilance when feeding on low quality sites, i.e., when concomitant increase in chewing time can be devoted to vigilance with limited costs. Our global approach was able to disentangle the sex-specific sources of variation in mouflon vigilance and stressed the importance of reserves in managing

  7. Human disturbances, habitat characteristics and social environment generate sex-specific responses in vigilance of Mediterranean mouflon.

    PubMed

    Benoist, Stéphanie; Garel, Mathieu; Cugnasse, Jean-Marc; Blanchard, Pierrick

    2013-01-01

    In prey species, vigilance is an important part of the decision making process related to predation risk effects. Therefore, understanding the mechanisms shaping vigilance behavior provides relevant insights on factors influencing individual fitness. We investigated the role of extrinsic and intrinsic factors on vigilance behavior in Mediterranean mouflon (Ovis gmelini musimon×Ovis sp.) in a study site spatially and temporally contrasted in human pressures. Both sexes were less vigilant in the wildlife reserve compared to surrounding unprotected areas, except for males during the hunting period. During this period, males tended to be less strictly restricted to the reserve than females what might lead to a pervasive effect of hunting within the protected area, resulting in an increase in male vigilance. It might also be a rutting effect that did not occur in unprotected areas because males vigilance was already maximal in response to human disturbances. In both sexes, yearlings were less vigilant than adults, probably because they traded off vigilance for learning and energy acquisition and/or because they relied on adult experience present in the group. Similarly, non-reproductive females benefited of the vigilance effort provided by reproductive females when belonging to the same group. However, in the absence of reproductive females, non-reproductive females were as vigilant as reproductive females. Increasing group size was only found to reduce vigilance in females (up to 17.5%), not in males. We also showed sex-specific responses to habitat characteristics. Females increased their vigilance when habitat visibility decreased (up to 13.8%) whereas males increased their vigilance when feeding on low quality sites, i.e., when concomitant increase in chewing time can be devoted to vigilance with limited costs. Our global approach was able to disentangle the sex-specific sources of variation in mouflon vigilance and stressed the importance of reserves in managing

  8. Dolphins maintain cognitive performance during 72 to 120 hours of continuous auditory vigilance.

    PubMed

    Ridgway, Sam; Keogh, Mandy; Carder, Don; Finneran, James; Kamolnick, Tricia; Todd, Mark; Goldblatt, Allen

    2009-05-01

    The present study reports the first use of a choice visual-vocal response time cognitive task, during 72 or 120 h of continuous auditory vigilance. Two adult bottlenose dolphins (Tursiops truncatus), NAY (male) and SAY (female), maintained a very high detection rate (91.1-98.7%) of random 1.5 s goal tones infrequently substituted in a background of frequent 0.5 s equal-amplitude tones over continuous 72 or 120 h sessions. In addition, a choice visual-vocal response time task (CVVRT) tested cognitive performance during night time sessions, when the dolphins would have ordinarily been resting or asleep as we had observed in previous studies. NAY and SAY detected a single-bar, posterior, vertical, green (S1g) or 3-bar, anterior, horizontal, red (S2r) LED light stimulus presented randomly to each eye. They responded with a different vocalization (whistle or pulse burst) to each stimulus (S1g or S2r) presented randomly to left and right eyes. The animals maintained high levels of goal tone detection without signs of sleep deprivation as indicated by behavior, blood indices or marked sleep rebound during 24 h of continuous post-experiment observation. Acoustic goal tone response time (AGTRT) overall did not change during the 72 h (F=0.528, P=0.655) or 120 h (F=0.384, P=0.816) sessions. Nor did CVVRT slow or degrade over the 72 h (F=4.188, P=0.104) or 120 h (F=2.298, P=0.119) AGTRT sessions. PMID:19411545

  9. Training for vigilance: the effect of knowledge of results format and dispositional optimism and pessimism on performance and stress.

    PubMed

    Szalma, James L; Hancock, Peter A; Dember, William N; Warm, Joel S

    2006-02-01

    This study investigated the impact of knowledge of results (KR) format on the performance and stress associated with a vigilance task. Also examined was the effect of the interaction of KR-format (Hit-KR, False Alarm-KR, Miss-KR, and a composite of all three formats) with dispositional optimism and pessimism on performance outcome and reported stress state. Hypotheses based upon a theory of feedback intervention were tested. KR regarding correct detections and the composite-KR (KR regarding correct detections, false alarms, and missed signals) enhanced perceptual sensitivity. However, False Alarm-KR and Miss-KR did not. Contrary to expectations based on the theory, performance was unrelated to the traits across all KR conditions. However, the effects of KR-format on self-reports of stress depended on the individual's level of pessimism and optimism. In addition, KR format and personality affected the multiple dimensions of stress state in different ways.

  10. Sturge-Weber syndrome: Continued vigilance is needed.

    PubMed

    Hassan, Saeed; Babiker, Amir; Bashiri, Fahad A; Hassan, Hamdi H; Husseini, Maha El; Salih, Mustafa A

    2015-01-01

    Sturge-Weber syndrome (SWS) is a non-hereditary congenital disorder due to somatic mosaic mutations in the GNAQ gene. The classical presentation relates to the brain lesion (cerebral angiomatous lesion of leptomeninges, which is responsible for epileptic seizures, hemiparesis and mental retardation), skin lesion (unilateral facial nevus), ocular and oral involvement. We present a 12-year-old boy who was referred to the Division of Pediatric Neurology, King Saud University Medical City, Riyadh, Saudi Arabia with left-sided hemiparesis. Physical examination showed a port wine stain involving the right side of the face, extending to the upper thorax, and enlargement of both the right eye globe and cornea (megalocornea), indicating the presence of glaucoma. Following urgent referral to ophthalmology service, his eye condition improved dramatically post surgery. Neuroradiological investigations, including cranial computed tomography (CT) and magnetic resonance angiography (MRI) revealed the classical brain lesions of SWS, as well as right leptomeningeal choroidal angioma. Ten months later, he developed focal-onset seizures which responded to treatment. His cognition is normal with good school performance. Continued vigilance is needed to identify and manage the complications of SWS. PMID:27493438

  11. Sturge-Weber syndrome: Continued vigilance is needed.

    PubMed

    Hassan, Saeed; Babiker, Amir; Bashiri, Fahad A; Hassan, Hamdi H; Husseini, Maha El; Salih, Mustafa A

    2015-01-01

    Sturge-Weber syndrome (SWS) is a non-hereditary congenital disorder due to somatic mosaic mutations in the GNAQ gene. The classical presentation relates to the brain lesion (cerebral angiomatous lesion of leptomeninges, which is responsible for epileptic seizures, hemiparesis and mental retardation), skin lesion (unilateral facial nevus), ocular and oral involvement. We present a 12-year-old boy who was referred to the Division of Pediatric Neurology, King Saud University Medical City, Riyadh, Saudi Arabia with left-sided hemiparesis. Physical examination showed a port wine stain involving the right side of the face, extending to the upper thorax, and enlargement of both the right eye globe and cornea (megalocornea), indicating the presence of glaucoma. Following urgent referral to ophthalmology service, his eye condition improved dramatically post surgery. Neuroradiological investigations, including cranial computed tomography (CT) and magnetic resonance angiography (MRI) revealed the classical brain lesions of SWS, as well as right leptomeningeal choroidal angioma. Ten months later, he developed focal-onset seizures which responded to treatment. His cognition is normal with good school performance. Continued vigilance is needed to identify and manage the complications of SWS.

  12. Diagnosing obstructive shock: Echocardiography is the third eye of a vigilant intensivist

    PubMed Central

    Lyall, Aditya; Ghosh, Supradip; Mishra, Kirtee

    2016-01-01

    Training in echocardiography is essential for an intensivist. We present a rapidly fatal case of obstructive shock where a vigilant intensivist could diagnose left atrial mass obstructing the mitral inflow as the etiology of shock. PMID:27688631

  13. Diagnosing obstructive shock: Echocardiography is the third eye of a vigilant intensivist.

    PubMed

    Lyall, Aditya; Ghosh, Supradip; Mishra, Kirtee

    2016-09-01

    Training in echocardiography is essential for an intensivist. We present a rapidly fatal case of obstructive shock where a vigilant intensivist could diagnose left atrial mass obstructing the mitral inflow as the etiology of shock. PMID:27688631

  14. Heritability of anti-predatory traits: vigilance and locomotor performance in marmots.

    PubMed

    Blumstein, D T; Lea, A J; Olson, L E; Martin, J G A

    2010-05-01

    Animals must allocate some proportion of their time to detecting predators. In birds and mammals, such anti-predator vigilance has been well studied, and we know that it may be influenced by a variety of intrinsic and extrinsic factors. Despite hundreds of studies focusing on vigilance and suggestions that there are individual differences in vigilance, there have been no prior studies examining its heritability in the field. Here, we present one of the first reports of (additive) genetic variation in vigilance. Using a restricted maximum likelihood procedure, we found that, in yellow-bellied marmots (Marmota flaviventris), the heritability of locomotor ability (h(2)=0.21), and especially vigilance (h(2) = 0.08), is low. These modest heritability estimates suggest great environmental variation or a history of directional selection eliminating genetic variation in these traits. We also found a significant phenotypic (r(P) = -0.09 +/- 0.04, P = 0.024) and a substantial, but not significant, genetic correlation (r(A) = -0.57 +/- 0.28, P = 0.082) between the two traits (slower animals are less vigilant while foraging). We found no evidence of differential survival or longevity associated with particular phenotypes of either trait. The genetic correlation may persist because of environmental heterogeneity and genotype-by-environment interactions maintaining the correlation, or because there are two ways to solve the problem of foraging in exposed areas: be very vigilant and rely on early detection coupled with speed to escape, or reduce vigilance to minimize time spent in an exposed location. Both strategies seem to be equally successful, and this 'locomotor ability-wariness' syndrome may therefore allow slow animals to compensate behaviourally for their impaired locomotor ability. PMID:20298440

  15. The effect of group size on vigilance in a semi-solitary, fossorial marsupial (Lasiorhinus latifrons).

    PubMed

    Descovich, Kristin A; Lisle, Allan T; Johnston, Stephen; Phillips, Clive J C

    2013-11-01

    Prey species that congregate gain protection against predatory attacks and this advantage is often reflected by a reduction in vigilance behaviour by individuals in larger groups. Comparatively few studies have investigated vigilance in solitary animals, but those that have, found that vigilance increases as group size increases because of the threat posed by conspecifics and/or competition for resources. The southern hairy-nosed wombat (Lasiorhinus latifrons) is a large fossorial, nocturnal marsupial that is neither strictly solitary nor gregarious, sharing warren systems with multiple conspecifics. We investigated the effects of conspecific presence on vigilance behaviour in this semi-solitary species. We observed wild-born, adult L. latifrons wombats in three group sizes (Large (1♂, 3♀), Medium (1♂, 2♀) and Small (1♂, 1♀)) in a captive, naturalistic environment that allowed above-ground and den behaviour monitoring. Vigilance behaviours were performed less frequently by wombats in large groups (e.g. scanning, counts/day, Large: 55, Medium: 69, Small: 115, P=0.002) and more frequently as the distance from their nearest conspecific increased (r64=0.30, P= 0.016). Vigilance within burrows was also affected by social influences, with solitary wombats significantly more vigilant than those denning with a conspecific (e.g. scanning: conspecific absent: 0.13/5min, present: 0.03/5min, P<0.0001). It is concluded that the presence of conspecifics reduces vigilance in L. latifrons wombats, even within burrows, and this may partially explain the occurrence of warren sharing in the wild. PMID:24140418

  16. The effect of group size on vigilance in a semi-solitary, fossorial marsupial (Lasiorhinus latifrons).

    PubMed

    Descovich, Kristin A; Lisle, Allan T; Johnston, Stephen; Phillips, Clive J C

    2013-11-01

    Prey species that congregate gain protection against predatory attacks and this advantage is often reflected by a reduction in vigilance behaviour by individuals in larger groups. Comparatively few studies have investigated vigilance in solitary animals, but those that have, found that vigilance increases as group size increases because of the threat posed by conspecifics and/or competition for resources. The southern hairy-nosed wombat (Lasiorhinus latifrons) is a large fossorial, nocturnal marsupial that is neither strictly solitary nor gregarious, sharing warren systems with multiple conspecifics. We investigated the effects of conspecific presence on vigilance behaviour in this semi-solitary species. We observed wild-born, adult L. latifrons wombats in three group sizes (Large (1♂, 3♀), Medium (1♂, 2♀) and Small (1♂, 1♀)) in a captive, naturalistic environment that allowed above-ground and den behaviour monitoring. Vigilance behaviours were performed less frequently by wombats in large groups (e.g. scanning, counts/day, Large: 55, Medium: 69, Small: 115, P=0.002) and more frequently as the distance from their nearest conspecific increased (r64=0.30, P= 0.016). Vigilance within burrows was also affected by social influences, with solitary wombats significantly more vigilant than those denning with a conspecific (e.g. scanning: conspecific absent: 0.13/5min, present: 0.03/5min, P<0.0001). It is concluded that the presence of conspecifics reduces vigilance in L. latifrons wombats, even within burrows, and this may partially explain the occurrence of warren sharing in the wild.

  17. Investigating Differences in Vigilance Tactic Use within and between the Sexes in Eastern Grey Kangaroos

    PubMed Central

    Rieucau, Guillaume; Blanchard, Pierrick; Martin, Julien G. A.; Favreau, François-René; Goldizen, Anne W.; Pays, Olivier

    2012-01-01

    Aggregation is thought to enhance an animal’s security through effective predator detection and the dilution of risk. A decline in individual vigilance as group size increases is commonly reported in the literature and called the group size effect. However, to date, most of the research has only been directed toward examining whether this effect occurs at the population level. Few studies have explored the specific contributions of predator detection and risk dilution and the basis of individual differences in the use of vigilance tactics. We tested whether male and female (non-reproductive or with young) eastern grey kangaroos (Macropus giganteus) adopted different vigilance tactics when in mixed-sex groups and varied in their reliance on predator detection and/or risk dilution as group size changed. This species exhibits pronounced sexual dimorphism with females being much smaller than males, making them differentially vulnerable toward predators. We combined field observations with vigilance models describing the effects of detection and dilution on scanning rates as group size increased. We found that females with and without juveniles relied on predator detection and risk dilution, but the latter adjusted their vigilance to the proportion of females with juveniles within their group. Two models appeared to equally support the data for males suggesting that males, similarly to females, relied on predator detection and risk dilution but may also have adjusted their vigilance according to the proportion of mothers within their group. Differential vulnerability may cause sex differences in vigilance tactic use in this species. The presence of males within a group that do not, or only partially, contribute to predator detection and are less at risk may cause additional security costs to females. Our results call for reexamination of the classical view of the safety advantages of grouping to provide a more detailed functional interpretation of gregariousness. PMID

  18. Investigating differences in vigilance tactic use within and between the sexes in eastern grey kangaroos.

    PubMed

    Rieucau, Guillaume; Blanchard, Pierrick; Martin, Julien G A; Favreau, François-René; Goldizen, Anne W; Pays, Olivier

    2012-01-01

    Aggregation is thought to enhance an animal's security through effective predator detection and the dilution of risk. A decline in individual vigilance as group size increases is commonly reported in the literature and called the group size effect. However, to date, most of the research has only been directed toward examining whether this effect occurs at the population level. Few studies have explored the specific contributions of predator detection and risk dilution and the basis of individual differences in the use of vigilance tactics. We tested whether male and female (non-reproductive or with young) eastern grey kangaroos (Macropus giganteus) adopted different vigilance tactics when in mixed-sex groups and varied in their reliance on predator detection and/or risk dilution as group size changed. This species exhibits pronounced sexual dimorphism with females being much smaller than males, making them differentially vulnerable toward predators. We combined field observations with vigilance models describing the effects of detection and dilution on scanning rates as group size increased. We found that females with and without juveniles relied on predator detection and risk dilution, but the latter adjusted their vigilance to the proportion of females with juveniles within their group. Two models appeared to equally support the data for males suggesting that males, similarly to females, relied on predator detection and risk dilution but may also have adjusted their vigilance according to the proportion of mothers within their group. Differential vulnerability may cause sex differences in vigilance tactic use in this species. The presence of males within a group that do not, or only partially, contribute to predator detection and are less at risk may cause additional security costs to females. Our results call for reexamination of the classical view of the safety advantages of grouping to provide a more detailed functional interpretation of gregariousness.

  19. Adverse Effects of Daylight Saving Time on Adolescents' Sleep and Vigilance

    PubMed Central

    Medina, Diana; Ebben, Matthew; Milrad, Sara; Atkinson, Brianna; Krieger, Ana C.

    2015-01-01

    Study Objectives: Daylight saving time (DST) has been established with the intent to reduce energy expenditure, however unintentional effects on sleep and vigilance have not been consistently measured. The objective of this study was to test the hypothesis that DST adversely affects high school students' sleep and vigilance on the school days following its implementation. Methods: A natural experiment design was used to assess baseline and post-DST differences in objective and subjective measures of sleep and vigilance by actigraphy, sleep diary, sleepiness scale, and psychomotor vigilance testing (PVT). Students were tested during school days immediately preceding and following DST. Results: A total of 40 high school students were enrolled in this study; 35 completed the protocol. Sleep duration declined by an average of 32 minutes on the weeknights post-DST, reflecting a cumulative sleep loss of 2 h 42 min as compared to the baseline week (p = 0.001). This finding was confirmed by sleep diary analyses, reflecting an average sleep loss of 27 min/night (p = 0.004) post-DST. Vigilance significantly deteriorated, with a decline in PVT performance post-DST, resulting in longer reaction times (p < 0.001) and increased lapses (p < 0.001). Increased daytime sleepiness was also demonstrated (p < 0.001). Conclusions: The early March DST onset adversely affected sleep and vigilance in high school students resulting in increased daytime sleepiness. Larger scale evaluations of sleep impairments related to DST are needed to further quantify this problem in the population. If confirmed, measures to attenuate sleep loss post-DST should be implemented. Citation: Medina D, Ebben M, Milrad S, Atkinson B, Krieger AC. Adverse effects of daylight saving time on adolescents' sleep and vigilance. J Clin Sleep Med 2015;11(8):879–884. PMID:25979095

  20. Repression versus sensitization in response to media violence as predictors of cognitive avoidance and vigilance.

    PubMed

    Krahé, Barbara; Möller, Ingrid; Berger, Anja; Felber, Juliane

    2011-02-01

    Repression and sensitization as situational modes of coping with anxiety were examined as predictors of trait measures of cognitive avoidance and vigilance. In this study, 303 undergraduates saw a violent film clip to elicit anxiety. Increases in skin conductance level (SCL) and state anxiety (STA) from baseline were measured to identify repressors (high SCL, low STA) and contrast them with sensitizers (low SCL, high STA) and genuinely low anxious individuals (low SCL, low STA). State anger was also recorded. Trait measures of vigilance and cognitive avoidance were collected 2 weeks earlier. Significant SCL × STA interactions indicated that repressors scored higher on cognitive avoidance and lower on vigilance compared to sensitizers and low anxious participants. Repressors were less likely than sensitizers to report gaze avoidance during the clip. The anger by SCL interaction was nonsignificant, suggesting that repressors and sensitizers differ specifically in the processing of anxiety rather than negative affect in general. PMID:21223268

  1. Psychophysiological Control of Acognitive Task Using Adaptive Automation

    NASA Technical Reports Server (NTRS)

    Freeman, Frederick; Pope, Alan T. (Technical Monitor)

    2001-01-01

    The major focus of the present proposal was to examine psychophysiological variables related to hazardous states of awareness induced by monitoring automated systems. With the increased use of automation in today's work environment, people's roles in the work place are being redefined from that of active participant to one of passive monitor. Although the introduction of automated systems has a number of benefits, there are also a number of disadvantages regarding worker performance. Byrne and Parasuraman have argued for the use of psychophysiological measures in the development and the implementation of adaptive automation. While both performance based and model based adaptive automation have been studied, the use of psychophysiological measures, especially EEG, offers the advantage of real time evaluation of the state of the subject. The current study used the closed-loop system, developed at NASA-Langley Research Center, to control the state of awareness of subjects while they performed a cognitive vigilance task. Previous research in our laboratory, supported by NASA, has demonstrated that, in an adaptive automation, closed-loop environment, subjects perform a tracking task better under a negative than a positive, feedback condition. In addition, this condition produces less subjective workload and larger P300 event related potentials to auditory stimuli presented in a concurrent oddball task. We have also recently shown that the closed-loop system used to control the level of automation in a tracking task can also be used to control the event rate of stimuli in a vigilance monitoring task. By changing the event rate based on the subject's index of arousal, we have been able to produce improved monitoring, relative to various control groups. We have demonstrated in our initial closed-loop experiments with the the vigilance paradigm that using a negative feedback contingency (i.e. increasing event rates when the EEG index is low and decreasing event rates when

  2. Protection from ischemic heart injury by a vigilant heme oxygenase-1 plasmid system.

    PubMed

    Tang, Yao Liang; Tang, Yi; Zhang, Y Clare; Qian, Keping; Shen, Leping; Phillips, M Ian

    2004-04-01

    Although human heme oxygenase-1 (hHO-1) could provide a useful approach for cellular protection in the ischemic heart, constitutive overexpression of hHO-1 may lead to unwanted side effects. To avoid this, we designed a hypoxia-regulated hHO-1 gene therapy system that can be switched on and off. This vigilant plasmid system is composed of myosin light chain-2v promoter and a gene switch that is based on an oxygen-dependent degradation domain from the hypoxia inducible factor-1-alpha. The vector can sense ischemia and switch on the hHO-1 gene system, specifically in the heart. In an in vivo experiment, the vigilant hHO-1 plasmid or saline was injected intramyocardially into myocardial infarction mice or sham operation mice. After gene transfer, expression of hHO-1 was only detected in the ischemic heart treated with vigilant hHO-1 plasmids. Masson trichrome staining showed significantly fewer fibrotic areas in vigilant hHO-1 plasmids-treated mice compared with saline control (43.0%+/-4.8% versus 62.5%+/-3.3%, P<0.01). The reduction of interstitial fibrosis is accompanied by an increase in myocardial hHO-1 expression in peri-infarct border areas, concomitant with higher Bcl-2 levels and lower Bax, Bak, and caspase 3 levels in the ischemic myocardium compared with saline control. By use of a cardiac catheter, heart from vigilant hHO-1 plasmids-treated mice showed improved recovery of contractile and diastolic performance after myocardial infarction compared with saline control. This study documents the beneficial regulation and therapeutic potential of vigilant plasmid-mediated hHO-1 gene transfer. This novel gene transfer strategy can provide cardiac-specific protection from future repeated bouts of ischemic injury.

  3. Task-Dependent Individual Differences in Prefrontal Connectivity

    PubMed Central

    Biswal, Bharat B.; Eldreth, Dana A.; Motes, Michael A.

    2010-01-01

    Recent advances in neuroimaging have permitted testing of hypotheses regarding the neural bases of individual differences, but this burgeoning literature has been characterized by inconsistent results. To test the hypothesis that differences in task demands could contribute to between-study variability in brain-behavior relationships, we had participants perform 2 tasks that varied in the extent of cognitive involvement. We examined connectivity between brain regions during a low-demand vigilance task and a higher-demand digit–symbol visual search task using Granger causality analysis (GCA). Our results showed 1) Significant differences in numbers of frontoparietal connections between low- and high-demand tasks 2) that GCA can detect activity changes that correspond with task-demand changes, and 3) faster participants showed more vigilance-related activity than slower participants, but less visual-search activity. These results suggest that relatively low-demand cognitive performance depends on spontaneous bidirectionally fluctuating network activity, whereas high-demand performance depends on a limited, unidirectional network. The nature of brain-behavior relationships may vary depending on the extent of cognitive demand. High-demand network activity may reflect the extent to which individuals require top-down executive guidance of behavior for successful task performance. Low-demand network activity may reflect task- and performance monitoring that minimizes executive requirements for guidance of behavior. PMID:20064942

  4. Human Activity Dampens the Benefits of Group Size on Vigilance in Khulan (Equus hemionus) in Western China.

    PubMed

    Wang, Mu-Yang; Ruckstuhl, Kathreen E; Xu, Wen-Xuan; Blank, David; Yang, Wei-Kang

    2016-01-01

    Animals receive anti-predator benefits from social behavior. As part of a group, individuals spend less time being vigilant, and vigilance decreases with increasing group size. This phenomenon, called "the many-eyes effect", together with the "encounter dilution effect", is considered among the most important factors determining individual vigilance behavior. However, in addition to group size, other social and environmental factors also influence the degree of vigilance, including disturbance from human activities. In our study, we examined vigilance behavior of Khulans (Equus hemionus) in the Xinjiang Province in western China to test whether and how human disturbance and group size affect vigilance. According to our results, Khulan showed a negative correlation between group size and the percentage time spent vigilant, although this negative correlation depended on the groups' disturbance level. Khulan in the more disturbed area had a dampened benefit from increases in group size, compared to those in the undisturbed core areas. Provision of continuous areas of high-quality habitat for Khulans will allow them to form larger undisturbed aggregations and to gain foraging benefits through reduced individual vigilance, as well as anti-predator benefits through increased probability of predator detection.

  5. Human Activity Dampens the Benefits of Group Size on Vigilance in Khulan (Equus hemionus) in Western China

    PubMed Central

    Wang, Mu-Yang; Ruckstuhl, Kathreen E.; Xu, Wen-Xuan; Blank, David; Yang, Wei-Kang

    2016-01-01

    Animals receive anti-predator benefits from social behavior. As part of a group, individuals spend less time being vigilant, and vigilance decreases with increasing group size. This phenomenon, called “the many-eyes effect”, together with the “encounter dilution effect”, is considered among the most important factors determining individual vigilance behavior. However, in addition to group size, other social and environmental factors also influence the degree of vigilance, including disturbance from human activities. In our study, we examined vigilance behavior of Khulans (Equus hemionus) in the Xinjiang Province in western China to test whether and how human disturbance and group size affect vigilance. According to our results, Khulan showed a negative correlation between group size and the percentage time spent vigilant, although this negative correlation depended on the groups’ disturbance level. Khulan in the more disturbed area had a dampened benefit from increases in group size, compared to those in the undisturbed core areas. Provision of continuous areas of high-quality habitat for Khulans will allow them to form larger undisturbed aggregations and to gain foraging benefits through reduced individual vigilance, as well as anti-predator benefits through increased probability of predator detection. PMID:26756993

  6. Fear of loss of vigilance: development and preliminary validation of a self-report instrument.

    PubMed

    Tsao, Jennie C I; Craske, Michelle G

    2003-01-01

    We describe the development and initial validation of the Fear of Loss of Vigilance Questionnaire (FLOVQ). Recent investigations indicate that individuals with nocturnal panic (NP) demonstrate increased anxiety and panic in response to meditative relaxation and imagined hypnosis, compared to those with daytime panic (DP) only, suggesting that NP individuals fear situations that involve a loss of vigilance (e.g., relaxation, fatigue and altered states of consciousness). The FLOVQ was designed to assess this construct and was tested in five non-clinical samples and one clinical sample. The 14-item instrument demonstrated good internal consistency and test-retest reliability. Non-clinical respondents who experienced NP endorsed greater fear of loss of vigilance than non-panickers; those who only experienced DP did not differ from the other groups. By contrast, on measures of trait and state anxiety, and anxiety sensitivity, both panic groups scored higher than non-panickers, suggesting that these latter measures were related to broader factors pertaining to a general tendency to panic versus a specific factor associated with NP. No group differences were found between NPs and DPs in either the non-clinical or the clinical sample, suggesting that fear of loss of vigilance may be a vulnerability factor for the development of NP and that the FLOVQ has more utility as a research rather than as a clinical instrument.

  7. Persistence of vigilance and flight response behaviour in wild reindeer with varying domestic ancestry.

    PubMed

    Reimers, E; Røed, K H; Colman, J E

    2012-08-01

    Knowledge about changes in behavioural traits related to wildness and tameness is for most mammals lacking, despite the increased trend of using domestic stock to re-establish wild populations into historical ranges. To test for persistence of behavioural traits of wild reindeer (Rangifer tarandus L.) exposed to hunting, we sampled DNA, vigilance and flight responses in wild reindeer herds with varying domestic ancestry. Analyses of 14 DNA microsatellite loci revealed a dichotomous main genetic structure reflecting their native origin, with the Rondane reindeer genetically different from the others and with least differentiation towards the Hardangervidda reindeer. The genetic clustering of the reindeer in Norefjell-Reinsjøfjell, Ottadalen and Forollhogna, together with domestic reindeer, supports a predominant domestic origin of these herds. Despite extensive hunting in all herds, the behavioural measures indicate increasing vigilance, alert and flight responses with increasing genetic dissimilarity with domestic herds. Vigilance frequency and time spent vigilant were higher in Rondane compared to Hardangervidda, which again were higher than herds with a domestic origin. We conclude that previous domestication has preserved a hard wired behavioural trait in some reindeer herds exhibiting less fright responses towards humans that extensive hunting has, but only slightly, altered. This brings novel and relevant knowledge to discussions about genetic diversity of wildlife in general and wild reindeer herds in Norway in specific.

  8. Netizenship Politics: Youth, Anti-Americanism, and Rhetorical Agency in South Korea's 2002 Candlelight Vigils

    ERIC Educational Resources Information Center

    Kang, Jiyeon

    2009-01-01

    This study offers a rhetorical analysis of the 2002 South Korean Candlelight Vigils ["ch'otpul siwi"] with a focus on the role of the Internet in public opinion building, the rise in anti-American sentiment in South Korea, and rhetorical agency residing in the collective. In 2002, two South Korean schoolgirls walking along a rural road near Seoul…

  9. 21 CFR 26.50 - Alert system and exchange of postmarket vigilance reports.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Alert system and exchange of postmarket vigilance reports. 26.50 Section 26.50 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL MUTUAL RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL...

  10. 21 CFR 26.50 - Alert system and exchange of postmarket vigilance reports.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Alert system and exchange of postmarket vigilance reports. 26.50 Section 26.50 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL MUTUAL RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL...

  11. 21 CFR 26.50 - Alert system and exchange of postmarket vigilance reports.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Alert system and exchange of postmarket vigilance reports. 26.50 Section 26.50 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL MUTUAL RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL...

  12. 21 CFR 26.50 - Alert system and exchange of postmarket vigilance reports.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Alert system and exchange of postmarket vigilance reports. 26.50 Section 26.50 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL MUTUAL RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL...

  13. Two-Year-Olds Are Vigilant of Others' Non-Verbal Cues to Credibility

    ERIC Educational Resources Information Center

    Birch, Susan A. J.; Akmal, Nazanin; Frampton, Kristen L.

    2010-01-01

    Data from three experiments provide the first evidence that children, at least as young as age two, are vigilant of others' non-verbal cues to credibility, and flexibly use these cues to facilitate learning. Experiment 1 revealed that 2- and 3-year-olds prefer to learn about objects from someone who appears, through non-verbal cues, to be…

  14. Body vigilance in nonclinical and anxiety disorder samples: structure, correlates, and prediction of health concerns.

    PubMed

    Olatunji, Bunmi O; Deacon, Brett J; Abramowitz, Jonathan S; Valentiner, David P

    2007-12-01

    The Body Vigilance Scale (BVS) is a measure developed to assess one's conscious attendance to internal cues. The present report investigated the structure, correlates, and predictive utility of the BVS in nonclinical (N=442) and anxiety (N=135) disorder samples. The findings of Study 1 suggest that the BVS is 1-dimensional in a nonclinical sample, and Study 2 replicated the factor structure of the BVS in an anxiety disorder sample. Correlations between the BVS and related (i.e., anxiety sensitivity) and unrelated (i.e., social anxiety) variables were consistent with predictions in both studies. Study 2 also showed that body vigilance is primarily elevated in patients with panic disorder relative to other anxiety disorders. Relative elevations in body vigilance were also observed for patients with hypochondriasis and generalized anxiety disorder. The BVS also demonstrated a specific association with medical utilization and health-related safety-seeking behaviors after controlling for related variables in nonclinical and anxiety disorder samples. The implications of our findings for the nature and measurement of body vigilance as a predictor of health concerns in anxiety disorders are considered.

  15. What can the drivers' own description from combined sources provide in an analysis of driver distraction and low vigilance in accident situations?

    PubMed

    Tivesten, Emma; Wiberg, Henrik

    2013-03-01

    Accident data play an important role in vehicle safety development. Accident data sources are generally limited in terms of how much information is provided on driver states and behaviour prior to an accident. However, the precise limitations vary between databases, due to differences in analysis focus and data collection procedures between organisations. If information about a specific accident can be retrieved from more than one data source it should be possible to combine the available information sets to facilitate data from one source to compensate for limitations in the other(s). To investigate the viability of such compensation, this study identified a set of accidents recorded in two different data sources. The first data source investigated was an accident mail survey and the second data source insurance claims documents consisting predominantly of insurance claims completed by the involved road users. An analysis of survey variables was compared to a case analysis including word data derived from the same survey and filed insurance claims documents. For each accident, the added value of having access to more than one source of information was assessed. To limit the scope of this study, three particular topics were investigated: available information on low vigilance (e.g., being drowsy, ill); secondary task distraction (e.g., talking with passengers, mobile phone use); and distraction related to the driving task (e.g., looking for approaching vehicles). Results suggest that for low vigilance and secondary task distraction, a combination of the mail survey and insurance claims documents provide more reliable and detailed pre-crash information than survey variables alone. However, driving related distraction appears to be more difficult to capture. In order to gain a better understanding of the above issues and how frequently they occur in accidents, the data sources and analysis methods suggested here may be combined with other investigation methods such

  16. What can the drivers' own description from combined sources provide in an analysis of driver distraction and low vigilance in accident situations?

    PubMed

    Tivesten, Emma; Wiberg, Henrik

    2013-03-01

    Accident data play an important role in vehicle safety development. Accident data sources are generally limited in terms of how much information is provided on driver states and behaviour prior to an accident. However, the precise limitations vary between databases, due to differences in analysis focus and data collection procedures between organisations. If information about a specific accident can be retrieved from more than one data source it should be possible to combine the available information sets to facilitate data from one source to compensate for limitations in the other(s). To investigate the viability of such compensation, this study identified a set of accidents recorded in two different data sources. The first data source investigated was an accident mail survey and the second data source insurance claims documents consisting predominantly of insurance claims completed by the involved road users. An analysis of survey variables was compared to a case analysis including word data derived from the same survey and filed insurance claims documents. For each accident, the added value of having access to more than one source of information was assessed. To limit the scope of this study, three particular topics were investigated: available information on low vigilance (e.g., being drowsy, ill); secondary task distraction (e.g., talking with passengers, mobile phone use); and distraction related to the driving task (e.g., looking for approaching vehicles). Results suggest that for low vigilance and secondary task distraction, a combination of the mail survey and insurance claims documents provide more reliable and detailed pre-crash information than survey variables alone. However, driving related distraction appears to be more difficult to capture. In order to gain a better understanding of the above issues and how frequently they occur in accidents, the data sources and analysis methods suggested here may be combined with other investigation methods such

  17. Does more sleep matter? Differential effects of NREM- and REM-dominant sleep on sleepiness and vigilance.

    PubMed

    Neu, D; Mairesse, O; Newell, J; Verbanck, P; Peigneux, P; Deliens, G

    2015-05-01

    We investigated effects of NREM and REM predominant sleep periods on sleepiness and psychomotor performances measured with visual analog scales and the psychomotor vigilance task, respectively. After one week of stable sleep-wake rhythms, 18 healthy sleepers slept 3hours of early sleep and 3hours of late sleep, under polysomnographic control, spaced by two hours of sustained wakefulness between sleep periods in a within subjects split-night, sleep interruption protocol. Power spectra analysis was applied for sleep EEG recordings and sleep phase-relative power proportions were computed for six different frequency bands (delta, theta, alpha, sigma, beta and gamma). Both sleep periods presented with similar sleep duration and efficiency. As expected, phasic NREM and REM predominances were obtained for early and late sleep conditions, respectively. Albeit revealing additive effects of total sleep duration, our results showed a systematic discrepancy between psychomotor performances and sleepiness levels. In addition, sleepiness remained stable throughout sustained wakefulness during both conditions, whereas psychomotor performances even decreased after the second sleep period. Disregarding exchanges for frequency bands in NREM or stability in REM, correlations between outcome measures and EEG power proportions further evidenced directional divergence with respect to sleepiness and psychomotor performances, respectively. Showing that the functional correlation pattern changed with respect to early and late sleep condition, the relationships between EEG power and subjective or behavioral outcomes might however essentially be related to total sleep duration rather than to the phasic predominance of REM or NREM sleep.

  18. Task breakdown

    NASA Technical Reports Server (NTRS)

    Pavlich, Jane

    1990-01-01

    The topics concerning the Center for Space Construction (CSC) space construction breakdown structure are presented in viewgraph form. It is concluded that four components describe a task -- effecting, information gathering, analysis, and regulation; uncertainties effect the relative amount of information gathering and analysis that occurs; and that task timing requirements drive the 'location in time' of cognition.

  19. Prediction of Vigilant Attention and Cognitive Performance Using Self-Reported Alertness, Circadian Phase, Hours since Awakening, and Accumulated Sleep Loss.

    PubMed

    Bermudez, Eduardo B; Klerman, Elizabeth B; Czeisler, Charles A; Cohen, Daniel A; Wyatt, James K; Phillips, Andrew J K

    2016-01-01

    Sleep restriction causes impaired cognitive performance that can result in adverse consequences in many occupational settings. Individuals may rely on self-perceived alertness to decide if they are able to adequately perform a task. It is therefore important to determine the relationship between an individual's self-assessed alertness and their objective performance, and how this relationship depends on circadian phase, hours since awakening, and cumulative lost hours of sleep. Healthy young adults (aged 18-34) completed an inpatient schedule that included forced desynchrony of sleep/wake and circadian rhythms with twelve 42.85-hour "days" and either a 1:2 (n = 8) or 1:3.3 (n = 9) ratio of sleep-opportunity:enforced-wakefulness. We investigated whether subjective alertness (visual analog scale), circadian phase (melatonin), hours since awakening, and cumulative sleep loss could predict objective performance on the Psychomotor Vigilance Task (PVT), an Addition/Calculation Test (ADD) and the Digit Symbol Substitution Test (DSST). Mathematical models that allowed nonlinear interactions between explanatory variables were evaluated using the Akaike Information Criterion (AIC). Subjective alertness was the single best predictor of PVT, ADD, and DSST performance. Subjective alertness alone, however, was not an accurate predictor of PVT performance. The best AIC scores for PVT and DSST were achieved when all explanatory variables were included in the model. The best AIC score for ADD was achieved with circadian phase and subjective alertness variables. We conclude that subjective alertness alone is a weak predictor of objective vigilant or cognitive performance. Predictions can, however, be improved by knowing an individual's circadian phase, current wake duration, and cumulative sleep loss. PMID:27019198

  20. Prediction of Vigilant Attention and Cognitive Performance Using Self-Reported Alertness, Circadian Phase, Hours since Awakening, and Accumulated Sleep Loss

    PubMed Central

    Bermudez, Eduardo B.; Klerman, Elizabeth B.; Czeisler, Charles A.; Cohen, Daniel A.; Wyatt, James K.; Phillips, Andrew J. K.

    2016-01-01

    Sleep restriction causes impaired cognitive performance that can result in adverse consequences in many occupational settings. Individuals may rely on self-perceived alertness to decide if they are able to adequately perform a task. It is therefore important to determine the relationship between an individual’s self-assessed alertness and their objective performance, and how this relationship depends on circadian phase, hours since awakening, and cumulative lost hours of sleep. Healthy young adults (aged 18–34) completed an inpatient schedule that included forced desynchrony of sleep/wake and circadian rhythms with twelve 42.85-hour “days” and either a 1:2 (n = 8) or 1:3.3 (n = 9) ratio of sleep-opportunity:enforced-wakefulness. We investigated whether subjective alertness (visual analog scale), circadian phase (melatonin), hours since awakening, and cumulative sleep loss could predict objective performance on the Psychomotor Vigilance Task (PVT), an Addition/Calculation Test (ADD) and the Digit Symbol Substitution Test (DSST). Mathematical models that allowed nonlinear interactions between explanatory variables were evaluated using the Akaike Information Criterion (AIC). Subjective alertness was the single best predictor of PVT, ADD, and DSST performance. Subjective alertness alone, however, was not an accurate predictor of PVT performance. The best AIC scores for PVT and DSST were achieved when all explanatory variables were included in the model. The best AIC score for ADD was achieved with circadian phase and subjective alertness variables. We conclude that subjective alertness alone is a weak predictor of objective vigilant or cognitive performance. Predictions can, however, be improved by knowing an individual’s circadian phase, current wake duration, and cumulative sleep loss. PMID:27019198

  1. Effects of Memory Load and Test Position on Short-Duration Sustained Attention Tasks.

    PubMed

    Laurie-Rose, Cynthia; Frey, Meredith C; Sibata, Erick; Zamary, Amanda

    2015-01-01

    The current study applies a dual-task working memory and vigilance task to examine sustained attention performance and perceived workload in a multi-instrument battery. In Experiment 1 we modified a task developed by Helton and Russell (2011) to examine declines in performance and to assess the effects of its position within a larger battery. Experiment 1 failed to reveal a sensitivity decrement, and test position revealed only spurious influence. Workload scores derived from the NASA-TLX fell at the high end of the scale, with mental and temporal demand receiving the highest ratings. In Experiment 2, we modified the dual task to place more emphasis on attention rather than working memory. Results revealed a significant decline in performance across the vigil for the perceptual sensitivity index A'. Test position (early vs. late) effects appeared with the reaction time variability measure, with performance becoming more variable when the task appeared in the latter half of the battery. Workload scores varied according to position in the battery: Workload scores were higher when the vigilance task appeared in the latter half of the battery. Practical and theoretical implications are discussed.

  2. The Moral, Epistemic, and Mindreading Components of Children's Vigilance towards Deception

    ERIC Educational Resources Information Center

    Mascaro, Olivier; Sperber, Dan

    2009-01-01

    Vigilance towards deception is investigated in 3- to-5-year-old children: (i) In Study 1, children as young as 3 years of age prefer the testimony of a benevolent rather than of a malevolent communicator. (ii) In Study 2, only at the age of four do children show understanding of the falsity of a lie uttered by a communicator described as a liar.…

  3. Dolphins can maintain vigilant behavior through echolocation for 15 days without interruption or cognitive impairment.

    PubMed

    Branstetter, Brian K; Finneran, James J; Fletcher, Elizabeth A; Weisman, Brian C; Ridgway, Sam H

    2012-01-01

    In dolphins, natural selection has developed unihemispheric sleep where alternating hemispheres of their brain stay awake. This allows dolphins to maintain consciousness in response to respiratory demands of the ocean. Unihemispheric sleep may also allow dolphins to maintain vigilant states over long periods of time. Because of the relatively poor visibility in the ocean, dolphins use echolocation to interrogate their environment. During echolocation, dolphin produce clicks and listen to returning echoes to determine the location and identity of objects. The extent to which individual dolphins are able to maintain continuous vigilance through this active sense is unknown. Here we show that dolphins may continuously echolocate and accurately report the presence of targets for at least 15 days without interruption. During a total of three sessions, each lasting five days, two dolphins maintained echolocation behaviors while successfully detecting and reporting targets. Overall performance was between 75 to 86% correct for one dolphin and 97 to 99% correct for a second dolphin. Both animals demonstrated diel patterns in echolocation behavior. A 15-day testing session with one dolphin resulted in near perfect performance with no significant decrement over time. Our results demonstrate that dolphins can continuously monitor their environment and maintain long-term vigilant behavior through echolocation. PMID:23082170

  4. Coordinated vigilance provides evidence for direct reciprocity in coral reef fishes

    PubMed Central

    Brandl, Simon J.; Bellwood, David R.

    2015-01-01

    Reciprocity is frequently assumed to require complex cognitive abilities. Therefore, it has been argued that reciprocity may be restricted to animals that can meet these demands. Here, we provide evidence for the potential presence of direct reciprocity in teleost fishes. We demonstrate that in pairs of coral reef rabbitfishes (f. Siganidae), one fish frequently assumes an upright vigilance position in the water column, while the partner forages in small crevices in the reef substratum. Both behaviours are strongly coordinated and partners regularly alternate their positions, resulting in a balanced distribution of foraging activity. Compared to solitary individuals, fishes in pairs exhibit longer vigilance bouts, suggesting that the help provided to the partner is costly. In turn, fishes in pairs take more consecutive bites and penetrate deeper into crevices than solitary individuals, suggesting that the safety provided by a vigilant partner may outweigh initial costs by increasing foraging efficiency. Thus, the described system appears to meet all of the requirements for direct reciprocity. We argue that the nature of rabbitfish pairs provides favourable conditions for the establishment of direct reciprocity, as continuous interaction with the same partner, simultaneous needs, interdependence, and communication relax the cognitive demands of reciprocal cooperation. PMID:26403250

  5. Coordinated vigilance provides evidence for direct reciprocity in coral reef fishes.

    PubMed

    Brandl, Simon J; Bellwood, David R

    2015-09-25

    Reciprocity is frequently assumed to require complex cognitive abilities. Therefore, it has been argued that reciprocity may be restricted to animals that can meet these demands. Here, we provide evidence for the potential presence of direct reciprocity in teleost fishes. We demonstrate that in pairs of coral reef rabbitfishes (f. Siganidae), one fish frequently assumes an upright vigilance position in the water column, while the partner forages in small crevices in the reef substratum. Both behaviours are strongly coordinated and partners regularly alternate their positions, resulting in a balanced distribution of foraging activity. Compared to solitary individuals, fishes in pairs exhibit longer vigilance bouts, suggesting that the help provided to the partner is costly. In turn, fishes in pairs take more consecutive bites and penetrate deeper into crevices than solitary individuals, suggesting that the safety provided by a vigilant partner may outweigh initial costs by increasing foraging efficiency. Thus, the described system appears to meet all of the requirements for direct reciprocity. We argue that the nature of rabbitfish pairs provides favourable conditions for the establishment of direct reciprocity, as continuous interaction with the same partner, simultaneous needs, interdependence, and communication relax the cognitive demands of reciprocal cooperation.

  6. Dolphins Can Maintain Vigilant Behavior through Echolocation for 15 Days without Interruption or Cognitive Impairment

    PubMed Central

    Branstetter, Brian K.; Finneran, James J.; Fletcher, Elizabeth A.; Weisman, Brian C.; Ridgway, Sam H.

    2012-01-01

    In dolphins, natural selection has developed unihemispheric sleep where alternating hemispheres of their brain stay awake. This allows dolphins to maintain consciousness in response to respiratory demands of the ocean. Unihemispheric sleep may also allow dolphins to maintain vigilant states over long periods of time. Because of the relatively poor visibility in the ocean, dolphins use echolocation to interrogate their environment. During echolocation, dolphin produce clicks and listen to returning echoes to determine the location and identity of objects. The extent to which individual dolphins are able to maintain continuous vigilance through this active sense is unknown. Here we show that dolphins may continuously echolocate and accurately report the presence of targets for at least 15 days without interruption. During a total of three sessions, each lasting five days, two dolphins maintained echolocation behaviors while successfully detecting and reporting targets. Overall performance was between 75 to 86% correct for one dolphin and 97 to 99% correct for a second dolphin. Both animals demonstrated diel patterns in echolocation behavior. A 15-day testing session with one dolphin resulted in near perfect performance with no significant decrement over time. Our results demonstrate that dolphins can continuously monitor their environment and maintain long-term vigilant behavior through echolocation. PMID:23082170

  7. How Preferences For Eager Versus Vigilant Judgment Strategies Affect Self-Serving Conclusions

    PubMed Central

    Molden, Daniel C.; Higgins, E. Tory

    2008-01-01

    People are often motivated to reach self-serving conclusions during judgment. This article examines how such self-serving judgment outcomes are influenced by preferences for different judgment strategies. Two studies tested how preferences for eager (promotion-oriented) versus vigilant (prevention-oriented) judgment strategies affected self-serving explanations for success or failure. Regardless of their performance, those preferring vigilant strategies selectively endorsed a few explanations above others, whereas those preferring eager strategies more evenly endorsed multiple explanations. Furthermore, although the explanations selected by those preferring vigilant strategies were indeed self-serving (emphasizing personal responsibility for success and external circumstances for failure), the more balanced endorsement of multiple explanations by those preferring eager strategies was associated with attenuated self-serving tendencies. Finally, those preferring eager strategies were also less self-serving in their generalization from explanations of current performance to predictions of future performance. The larger implications of these findings for the role of strategic preferences in judgment are discussed. PMID:19727421

  8. Antipredator vigilance of juvenile and adult thirteen-lined ground squirrels and the role of nutritional need.

    PubMed

    Arenz; Leger

    2000-03-01

    Juvenile thirteen-lined ground squirrels, Spermophilus tridecemlineatus, are less vigilant (i.e. they spend less time visually scanning the environment) than adults. To determine whether nutritional need was a potential cause of this difference, we supplemented two groups of free-ranging juveniles during the predispersal stage, while juveniles were still near and around the natal burrows. The high-energy food group (HEF: 11 squirrels) received peanut butter and oats while the low-energy food group (LEF: seven squirrels) received lettuce. Adults (14 squirrels) were also supplemented, but due to their greater home range sizes, it was not feasible to classify them as either HEF or LEF. To evaluate the effect of supplementation on antipredator vigilance, the behavioural act of visually scanning for predators, we videotaped individuals while they were foraging above ground during 5-min observation periods. Each squirrel was observed and weighed during three time periods over 23 days. From the videotape, we extracted measures of time spent vigilant, locomoting and foraging. All three categories of squirrels gained mass over the study period, but the HEF juveniles rapidly exceeded that of the LEF juveniles. Early in the study, LEF and HEF juveniles did not significantly differ in either body mass or time budgets, and, initially, both juvenile groups were similar to adults in the amount of time devoted to vigilance. Later in the study, the behaviour of HEF juveniles closely resembled that of adults (increased time devoted to vigilance and decreased time devoted to foraging), while LEF juveniles decreased vigilance and increased their foraging time. This study indicates that for thirteen-lined ground squirrels the lower vigilance of juveniles is due, at least in part, to the greater nutritional needs of young animals with consequent increases in foraging, which is largely incompatible with vigilance. Copyright 2000 The Association for the Study of Animal Behaviour. PMID

  9. Objective markers for sleep propensity: comparison between the Multiple Sleep Latency Test and the Vigilance Algorithm Leipzig.

    PubMed

    Olbrich, Sebastian; Fischer, Marie M; Sander, Christian; Hegerl, Ulrich; Wirtz, Hubert; Bosse-Henck, Andrea

    2015-08-01

    The regulation of wakefulness is important for high-order organisms. Its dysregulation is involved in the pathomechanism of several psychiatric disorders. Thus, a tool for its objective but little time-consuming assessment would be of importance. The Vigilance Algorithm Leipzig allows the objective measurement of sleep propensity, based on a single resting state electroencephalogram. To compare the Vigilance Algorithm Leipzig with the standard for objective assessment of excessive daytime sleepiness, a four-trial Multiple Sleep Latency Test in 25 healthy subjects was conducted. Between the first two trials, a 15-min, 25-channel resting electroencephalogram was recorded, and Vigilance Algorithm Leipzig was used to classify the sleep propensity (i.e., type of vigilance regulation) of each subject. The results of both methods showed significant correlations with the Epworth Sleepiness Scale (ρ = -0.70; ρ = 0.45, respectively) and correlated with each other (ρ = -0.54). Subjects with a stable electroencephalogram-vigilance regulation yielded significant increased sleep latencies compared with an unstable regulation (multiple sleep latency 898.5 s versus 549.9 s; P = 0.03). Further, Vigilance Algorithm Leipzig classifications allowed the identification of subjects with average sleep latencies <6 min with a sensitivity of 100% and a specificity of 77%. Thus, Vigilance Algorithm Leipzig provides similar information on wakefulness regulation in comparison to the much more cost- and time-consuming Multiple Sleep Latency Test. Due to its high sensitivity and specificity for large sleep propensity, Vigilance Algorithm Leipzig could be an effective and reliable alternative to the Multiple Sleep Latency Test, for example for screening purposes in large cohorts, where objective information about wakefulness regulation is needed.

  10. Vigilance and Activity Time-Budget Adjustments of Wintering Hooded Cranes, Grus monacha, in Human-Dominated Foraging Habitats

    PubMed Central

    Li, Chunlin; Zhou, Lizhi; Xu, Li; Zhao, Niannian; Beauchamp, Guy

    2015-01-01

    Due to loss and degradation of natural wetlands, waterbirds increasingly rely on surrounding human-dominated habitats to obtain food. Quantifying vigilance patterns, investigating the trade-off among various activities, and examining the underlying mechanisms will help us understand how waterbirds adapt to human-caused disturbances. During two successive winters (November-February of 2012–13 and 2013–14), we studied the hooded crane, Grus monacha, in the Shengjin Lake National Nature Reserve (NNR), China, to investigate how the species responds to human disturbances through vigilance and activity time-budget adjustments. Our results showed striking differences in the behavior of the cranes when foraging in the highly disturbed rice paddy fields found in the buffer zone compared with the degraded natural wetlands in the core area of the NNR. Time spent vigilant decreased with flock size and cranes spent more time vigilant in the human-dominated buffer zone. In the rice paddy fields, the birds were more vigilant but also fed more at the expense of locomotion and maintenance activities. Adult cranes spent more time vigilant and foraged less than juveniles. We recommend habitat recovery in natural wetlands and community co-management in the surrounding human-dominated landscape for conservation of the hooded crane and, generally, for the vast numbers of migratory waterbirds wintering in the middle and lower reaches of the Yangtze River floodplain. PMID:25768111

  11. Vigilance and activity time-budget adjustments of wintering hooded cranes, Grus monacha, in human-dominated foraging habitats.

    PubMed

    Li, Chunlin; Zhou, Lizhi; Xu, Li; Zhao, Niannian; Beauchamp, Guy

    2015-01-01

    Due to loss and degradation of natural wetlands, waterbirds increasingly rely on surrounding human-dominated habitats to obtain food. Quantifying vigilance patterns, investigating the trade-off among various activities, and examining the underlying mechanisms will help us understand how waterbirds adapt to human-caused disturbances. During two successive winters (November-February of 2012-13 and 2013-14), we studied the hooded crane, Grus monacha, in the Shengjin Lake National Nature Reserve (NNR), China, to investigate how the species responds to human disturbances through vigilance and activity time-budget adjustments. Our results showed striking differences in the behavior of the cranes when foraging in the highly disturbed rice paddy fields found in the buffer zone compared with the degraded natural wetlands in the core area of the NNR. Time spent vigilant decreased with flock size and cranes spent more time vigilant in the human-dominated buffer zone. In the rice paddy fields, the birds were more vigilant but also fed more at the expense of locomotion and maintenance activities. Adult cranes spent more time vigilant and foraged less than juveniles. We recommend habitat recovery in natural wetlands and community co-management in the surrounding human-dominated landscape for conservation of the hooded crane and, generally, for the vast numbers of migratory waterbirds wintering in the middle and lower reaches of the Yangtze River floodplain.

  12. Vigilance and activity time-budget adjustments of wintering hooded cranes, Grus monacha, in human-dominated foraging habitats.

    PubMed

    Li, Chunlin; Zhou, Lizhi; Xu, Li; Zhao, Niannian; Beauchamp, Guy

    2015-01-01

    Due to loss and degradation of natural wetlands, waterbirds increasingly rely on surrounding human-dominated habitats to obtain food. Quantifying vigilance patterns, investigating the trade-off among various activities, and examining the underlying mechanisms will help us understand how waterbirds adapt to human-caused disturbances. During two successive winters (November-February of 2012-13 and 2013-14), we studied the hooded crane, Grus monacha, in the Shengjin Lake National Nature Reserve (NNR), China, to investigate how the species responds to human disturbances through vigilance and activity time-budget adjustments. Our results showed striking differences in the behavior of the cranes when foraging in the highly disturbed rice paddy fields found in the buffer zone compared with the degraded natural wetlands in the core area of the NNR. Time spent vigilant decreased with flock size and cranes spent more time vigilant in the human-dominated buffer zone. In the rice paddy fields, the birds were more vigilant but also fed more at the expense of locomotion and maintenance activities. Adult cranes spent more time vigilant and foraged less than juveniles. We recommend habitat recovery in natural wetlands and community co-management in the surrounding human-dominated landscape for conservation of the hooded crane and, generally, for the vast numbers of migratory waterbirds wintering in the middle and lower reaches of the Yangtze River floodplain. PMID:25768111

  13. No Effects of Acute Exposure to Wi-Fi Electromagnetic Fields on Spontaneous EEG Activity and Psychomotor Vigilance in Healthy Human Volunteers.

    PubMed

    Zentai, Norbert; Csathó, Árpád; Trunk, Attila; Fiocchi, Serena; Parazzini, Marta; Ravazzani, Paolo; Thuróczy, György; Hernádi, István

    2015-12-01

    Mobile equipment use of wireless fidelity (Wi-Fi) signal modulation has increased exponentially in the past few decades. However, there is inconclusive scientific evidence concerning the potential risks associated with the energy deposition in the brain from Wi-Fi and whether Wi-Fi electromagnetism interacts with cognitive function. In this study we investigated possible neurocognitive effects caused by Wi-Fi exposure. First, we constructed a Wi-Fi exposure system from commercial parts. Dosimetry was first assessed by free space radiofrequency field measurements. The experimental exposure system was then modeled based on real geometry and physical characteristics. Specific absorption rate (SAR) calculations were performed using a whole-body, realistic human voxel model with values corresponding to conventional everyday Wi-Fi exposure (peak SAR10g level was 99.22 mW/kg with 1 W output power and 100% duty cycle). Then, in two provocation experiments involving healthy human volunteers we tested for two hypotheses: 1. Whether a 60 min long 2.4 GHz Wi-Fi exposure affects the spectral power of spontaneous awake electroencephalographic (sEEG) activity (N = 25); and 2. Whether similar Wi-Fi exposure modulates the sustained attention measured by reaction time in a computerized psychomotor vigilance test (PVT) (N = 19). EEG data were recorded at midline electrode sites while volunteers watched a silent documentary. In the PVT task, button press reaction time was recorded. No measurable effects of acute Wi-Fi exposure were found on spectral power of sEEG or reaction time in the psychomotor vigilance test. These results indicate that a single, 60 min Wi-Fi exposure does not alter human oscillatory brain function or objective measures of sustained attention. PMID:26600173

  14. No Effects of Acute Exposure to Wi-Fi Electromagnetic Fields on Spontaneous EEG Activity and Psychomotor Vigilance in Healthy Human Volunteers.

    PubMed

    Zentai, Norbert; Csathó, Árpád; Trunk, Attila; Fiocchi, Serena; Parazzini, Marta; Ravazzani, Paolo; Thuróczy, György; Hernádi, István

    2015-12-01

    Mobile equipment use of wireless fidelity (Wi-Fi) signal modulation has increased exponentially in the past few decades. However, there is inconclusive scientific evidence concerning the potential risks associated with the energy deposition in the brain from Wi-Fi and whether Wi-Fi electromagnetism interacts with cognitive function. In this study we investigated possible neurocognitive effects caused by Wi-Fi exposure. First, we constructed a Wi-Fi exposure system from commercial parts. Dosimetry was first assessed by free space radiofrequency field measurements. The experimental exposure system was then modeled based on real geometry and physical characteristics. Specific absorption rate (SAR) calculations were performed using a whole-body, realistic human voxel model with values corresponding to conventional everyday Wi-Fi exposure (peak SAR10g level was 99.22 mW/kg with 1 W output power and 100% duty cycle). Then, in two provocation experiments involving healthy human volunteers we tested for two hypotheses: 1. Whether a 60 min long 2.4 GHz Wi-Fi exposure affects the spectral power of spontaneous awake electroencephalographic (sEEG) activity (N = 25); and 2. Whether similar Wi-Fi exposure modulates the sustained attention measured by reaction time in a computerized psychomotor vigilance test (PVT) (N = 19). EEG data were recorded at midline electrode sites while volunteers watched a silent documentary. In the PVT task, button press reaction time was recorded. No measurable effects of acute Wi-Fi exposure were found on spectral power of sEEG or reaction time in the psychomotor vigilance test. These results indicate that a single, 60 min Wi-Fi exposure does not alter human oscillatory brain function or objective measures of sustained attention.

  15. The interplay between aerobic metabolism and antipredator performance: vigilance is related to recovery rate after exercise.

    PubMed

    Killen, Shaun S; Reid, Donald; Marras, Stefano; Domenici, Paolo

    2015-01-01

    When attacked by a predator, fish respond with a sudden fast-start motion away from the threat. Although this anaerobically-powered swimming necessitates a recovery phase which is fueled aerobically, little is known about links between escape performance and aerobic traits such as aerobic scope (AS) or recovery time after exhaustive exercise. Slower recovery ability or a reduced AS could make some individuals less likely to engage in a fast-start response or display reduced performance. Conversely, increased vigilance in some individuals could permit faster responses to an attack but also increase energy demand and prolong recovery after anaerobic exercise. We examined how AS and the ability to recover from anaerobic exercise relates to differences in fast-start escape performance in juvenile golden gray mullet at different acclimation temperatures. Individuals were acclimated to either 18, 22, or 26°C, then measured for standard and maximal metabolic rates and AS using intermittent flow respirometry. Anaerobic capacity and the time taken to recover after exercise were also assessed. Each fish was also filmed during a simulated attack to determine response latency, maximum speed and acceleration, and turning rate displayed during the escape response. Across temperatures, individuals with shorter response latencies during a simulated attack are those with the longest recovery time after exhaustive anaerobic exercise. Because a short response latency implies high preparedness to escape, these results highlight the trade-off between the increased vigilance and metabolic demand, which leads to longer recovery times in fast reactors. These results improve our understanding of the intrinsic physiological traits that generate inter-individual variability in escape ability, and emphasize that a full appreciation of trade-offs associated with predator avoidance and energy balance must include energetic costs associated with vigilance and recovery from anaerobic exercise.

  16. The interplay between aerobic metabolism and antipredator performance: vigilance is related to recovery rate after exercise

    PubMed Central

    Killen, Shaun S.; Reid, Donald; Marras, Stefano; Domenici, Paolo

    2015-01-01

    When attacked by a predator, fish respond with a sudden fast-start motion away from the threat. Although this anaerobically-powered swimming necessitates a recovery phase which is fueled aerobically, little is known about links between escape performance and aerobic traits such as aerobic scope (AS) or recovery time after exhaustive exercise. Slower recovery ability or a reduced AS could make some individuals less likely to engage in a fast-start response or display reduced performance. Conversely, increased vigilance in some individuals could permit faster responses to an attack but also increase energy demand and prolong recovery after anaerobic exercise. We examined how AS and the ability to recover from anaerobic exercise relates to differences in fast-start escape performance in juvenile golden gray mullet at different acclimation temperatures. Individuals were acclimated to either 18, 22, or 26°C, then measured for standard and maximal metabolic rates and AS using intermittent flow respirometry. Anaerobic capacity and the time taken to recover after exercise were also assessed. Each fish was also filmed during a simulated attack to determine response latency, maximum speed and acceleration, and turning rate displayed during the escape response. Across temperatures, individuals with shorter response latencies during a simulated attack are those with the longest recovery time after exhaustive anaerobic exercise. Because a short response latency implies high preparedness to escape, these results highlight the trade-off between the increased vigilance and metabolic demand, which leads to longer recovery times in fast reactors. These results improve our understanding of the intrinsic physiological traits that generate inter-individual variability in escape ability, and emphasize that a full appreciation of trade-offs associated with predator avoidance and energy balance must include energetic costs associated with vigilance and recovery from anaerobic exercise

  17. Age differences in arousal and vigilance in California ground squirrels (Spermophilus beecheyi).

    PubMed

    Hanson, M T; Coss, R G

    2001-11-01

    Newly emerged pup, juvenile, and adult California ground squirrels (Spermophilus beecheyi douglasii) were videorecorded at a seminatural field site in northern California. Video data revealed age differences in the budgeting of ground squirrel behavior, habitat use, and physiological arousal as indicated by morphometric analyses of tail piloerection. Adults and juveniles devoted their time to foraging in the open at feeding stations while displaying low to moderate levels of arousal, respectively. Pups remained vigilant on the fringe of covered habitats while displaying comparatively higher levels of arousal. Higher pup arousal may facilitate memory formation during early stages of development. PMID:11745313

  18. Do smoking intensity-related differences in vigilance indicate altered glucocorticoid receptor sensitivity?

    PubMed

    Reuter, Martin; Hennig, Juergen; Netter, Petra

    2004-03-01

    The relationship of critical flicker fusion frequency (CFF) and a pharmacologically induced cortisol suppression by means of dexamethasone (DEX) and metyrapone (MET) was investigated during nicotine deprivation in a between-subjects design in 60 male smokers divided into light, medium and heavy smokers. DEX reduced vigilance in medium smokers and improved it in heavy smokers compared to placebo, whereas MET was more detrimental in heavy smokers. The hypothesis was put forward that the intensity of nicotine consumption is related to differences in glucocorticoid and mineralocorticoid receptor sensitivity.

  19. The Vigil Network: a means of observing landscape change in drainage basins

    USGS Publications Warehouse

    Osterkamp, W.R.; Emmett, W.W.; Leopold, L.B.

    1991-01-01

    Long-term monitoring of geomorphic, hydrological, and biological characteristics of landscapes provides an effective means of relating observed changes to possible causes of the change. Identification of changes in basin characteristics, especially in arid areas where the response to altered climate or land use is generally rapid and readily apparent, might provide the initial direct indications that factors such as global warming and cultural impacts have affected the environment. The Vigil Network is an ever-increasing group of sites and basins used to monitor landscape features with as much as 50 years of documented geomorphic and related observations. -from Authors

  20. OpenVigil FDA – Inspection of U.S. American Adverse Drug Events Pharmacovigilance Data and Novel Clinical Applications

    PubMed Central

    Böhm, Ruwen; von Hehn, Leocadie; Herdegen, Thomas; Klein, Hans-Joachim; Bruhn, Oliver; Petri, Holger; Höcker, Jan

    2016-01-01

    Pharmacovigilance contributes to health care. However, direct access to the underlying data for academic institutions and individual physicians or pharmacists is intricate, and easily employable analysis modes for everyday clinical situations are missing. This underlines the need for a tool to bring pharmacovigilance to the clinics. To address these issues, we have developed OpenVigil FDA, a novel web-based pharmacovigilance analysis tool which uses the openFDA online interface of the Food and Drug Administration (FDA) to access U.S. American and international pharmacovigilance data from the Adverse Event Reporting System (AERS). OpenVigil FDA provides disproportionality analyses to (i) identify the drug most likely evoking a new adverse event, (ii) compare two drugs concerning their safety profile, (iii) check arbitrary combinations of two drugs for unknown drug-drug interactions and (iv) enhance the relevance of results by identifying confounding factors and eliminating them using background correction. We present examples for these applications and discuss the promises and limits of pharmacovigilance, openFDA and OpenVigil FDA. OpenVigil FDA is the first public available tool to apply pharmacovigilance findings directly to real-life clinical problems. OpenVigil FDA does not require special licenses or statistical programs. PMID:27326858

  1. OpenVigil FDA - Inspection of U.S. American Adverse Drug Events Pharmacovigilance Data and Novel Clinical Applications.

    PubMed

    Böhm, Ruwen; von Hehn, Leocadie; Herdegen, Thomas; Klein, Hans-Joachim; Bruhn, Oliver; Petri, Holger; Höcker, Jan

    2016-01-01

    Pharmacovigilance contributes to health care. However, direct access to the underlying data for academic institutions and individual physicians or pharmacists is intricate, and easily employable analysis modes for everyday clinical situations are missing. This underlines the need for a tool to bring pharmacovigilance to the clinics. To address these issues, we have developed OpenVigil FDA, a novel web-based pharmacovigilance analysis tool which uses the openFDA online interface of the Food and Drug Administration (FDA) to access U.S. American and international pharmacovigilance data from the Adverse Event Reporting System (AERS). OpenVigil FDA provides disproportionality analyses to (i) identify the drug most likely evoking a new adverse event, (ii) compare two drugs concerning their safety profile, (iii) check arbitrary combinations of two drugs for unknown drug-drug interactions and (iv) enhance the relevance of results by identifying confounding factors and eliminating them using background correction. We present examples for these applications and discuss the promises and limits of pharmacovigilance, openFDA and OpenVigil FDA. OpenVigil FDA is the first public available tool to apply pharmacovigilance findings directly to real-life clinical problems. OpenVigil FDA does not require special licenses or statistical programs. PMID:27326858

  2. Time-on-task decrements in "steer clear" performance of patients with sleep apnea and narcolepsy

    NASA Technical Reports Server (NTRS)

    Findley, L. J.; Suratt, P. M.; Dinges, D. F.

    1999-01-01

    Loss of attention with time-on-task reflects the increasing instability of the waking state during performance in experimentally induced sleepiness. To determine whether patients with disorders of excessive sleepiness also displayed time-on-task decrements indicative of wake state instability, visual sustained attention performance on "Steer Clear," a computerized simple RT driving simulation task, was compared among 31 patients with untreated sleep apnea, 16 patients with narcolepsy, and 14 healthy control subjects. Vigilance decrement functions were generated by analyzing the number of collisions in each of six four-minute periods of Steer Clear task performance in a mixed-model analysis of variance and linear regression equations. As expected, patients had more Steer Clear collisions than control subjects (p=0.006). However, the inter-subject variability in errors among the narcoleptic patients was four-fold that of the apnea patients, and 100-fold that of the controls volunteers; the variance in errors among untreated apnea patients was 27-times that of controls. The results of transformed collision data revealed main effects for group (p=0.006), time-on-task (p=0.001), and a significant interaction (p=0.022). Control subjects showed no clear evidence of increasing collision errors with time-on-task (adjusted R2=0.22), while apnea patients showed a trend toward vigilance decrement (adjusted R2=0.42, p=0.097), and narcolepsy patients evidenced a robust linear vigilance decrement (adjusted R2=0.87, p=0.004). The association of disorders of excessive somnolence with escalating time-on-task decrements makes it imperative that when assessment of neurobehavioral performance is conducted in patients, it involves task durations and analyses that will evaluate the underlying vulnerability of potentially sleepy patients to decrements over time in tasks that require sustained attention and timely responses, both of which are key components in safe driving performance.

  3. High-peak-power microwave pulses at 2. 37 GHz: No effects on vigilance performance in monkeys. Interim report, February 1988-February 1989

    SciTech Connect

    D'Andrea, J.A.; Knepton, J.; Cobb, B.L.; Klauenberg, B.J.; Merritt, J.H.

    1989-11-02

    The current safety standards for occupational exposure radio frequency and microwave exposure do not limit the peak power of microwave pulses. To evaluate whether short-duration (93 ns) high-peak-power microwave pulses can alter behavioral performance, four rhesus monkeys were exposed to peak powers of 7.02-11.30 kW/cm2 while they performed a vigilance task. The behavior consisted of two components: responding on a variable interval schedule on one lever and to reaction time on a second lever. Correct responding on each lever was signaled by auditory stimuli. Trained monkeys performed the task during exposure to 2.37-GHz microwave pulses delivered concurrently with the auditory signals. The estimated peak whole-body specific absorption rate (SAR) for each pulse was between 582.7 and 937.9 kW/kg (54-87 mJ/kg per pulse). Compared to sham irradiation, significant changes in behavioral performance were not observed.

  4. Neurofeedback in ADHD and insomnia: vigilance stabilization through sleep spindles and circadian networks.

    PubMed

    Arns, Martijn; Kenemans, J Leon

    2014-07-01

    In this review article an overview of the history and current status of neurofeedback for the treatment of ADHD and insomnia is provided. Recent insights suggest a central role of circadian phase delay, resulting in sleep onset insomnia (SOI) in a sub-group of ADHD patients. Chronobiological treatments, such as melatonin and early morning bright light, affect the suprachiasmatic nucleus. This nucleus has been shown to project to the noradrenergic locus coeruleus (LC) thereby explaining the vigilance stabilizing effects of such treatments in ADHD. It is hypothesized that both Sensori-Motor Rhythm (SMR) and Slow-Cortical Potential (SCP) neurofeedback impact on the sleep spindle circuitry resulting in increased sleep spindle density, normalization of SOI and thereby affect the noradrenergic LC, resulting in vigilance stabilization. After SOI is normalized, improvements on ADHD symptoms will occur with a delayed onset of effect. Therefore, clinical trials investigating new treatments in ADHD should include assessments at follow-up as their primary endpoint rather than assessments at outtake. Furthermore, an implication requiring further study is that neurofeedback could be stopped when SOI is normalized, which might result in fewer sessions.

  5. Adult rat vigilance states discrimination by artificial neural networks using a single EEG channel.

    PubMed

    Robert, C; Karasinski, P; Natowicz, R; Limoge, A

    1996-06-01

    Two multilayer neural networks were designed to discriminate vigilance states (waking, paradoxical sleep, and non-REM sleep) in the rat using a single parieto-occipital EEG derivation. After filtering (bandwidth 3.18-25 Hz) and digitization at 512 HZ, the EEG signal was segmented into eight second epochs. Five variables (three statistical, two temporal) were extracted from each epoch. The first network computed an epoch by epoch classification, while the second network also utilized contextual information from contiguous epochs. A specific postprocessing procedure was developed to enhance the vigilance state discrimination of the neural networks designed and especially paradoxical sleep state estimation. The classifications made by the networks (with or without the postprocessing procedure) for six rats were compared to these made by two human experts using EMG and EEG informations on 63,000 epochs. High rates of agreement (> 90%) between humans and neural networks classifications were obtained. In view of its development possibilities and its applicability to other signals, this method could prove of value in biomedical research. PMID:8737892

  6. Better, Stronger, Faster Self-Serving Judgment, Affect Regulation, and the Optimal Vigilance Hypothesis

    PubMed Central

    Roese, Neal J.; Olson, James M.

    2008-01-01

    Self-serving judgments, in which the self is viewed more favorably than other people, are ubiquitous. Their dynamic variation within individuals may be explained in terms of the regulation of affect. Self-serving judgments produce positive emotions, and threat increases self-serving judgments (a compensatory pattern that restores affect to a set point or baseline). Perceived mutability is a key moderator of these judgments; low mutability (i.e., the circumstance is closed to modification) triggers a cognitive response aimed at affect regulation, whereas high mutability (i.e., the circumstance is open to further modification) activates direct behavioral remediation. Threats often require immediate response, whereas positive events do not. Because of this brief temporal window, an active mechanism is needed to restore negative (but not positive) affective shifts back to a set point. Without this active reset, an earlier threat would make the individual less vigilant toward a new threat. Thus, when people are sad, they aim to return their mood to baseline, often via self-serving judgments. We argue that asymmetric homeostasis enables optimal vigilance, which establishes a coherent theoretical account of the role of self-serving judgments in affect regulation. PMID:18552989

  7. Catching and correcting near misses: the collective vigilance and individual accountability trade-off.

    PubMed

    Jeffs, Lianne Patricia; Lingard, Lorelei; Berta, Whitney; Baker, G Ross

    2012-03-01

    Despite the focus on patient safety and quality health care for the last two decades, there is still limited understanding of how interprofessional interactions at an organizational or work unit level influence how clinicians perceive and respond to safety events and errors. Within the rubric of safety events, there has been a growing interest in near misses as precursors to adverse events in health care. Given the interactive nature of the variety of professionals working together in the delivery of health care, understanding how the different clinicians experience and respond to near misses in practice is important. A constructivist grounded theory approach was employed for this study which included semi-structured interviews with 24 participants in a large teaching hospital in Canada. Findings from this study provide a deeper understanding into how different clinicians experience and respond to near misses in clinical practice. This understanding indicates that collective vigilance can potentially create risk by eroding individual professional accountability through reliance on other team members to catch and correct their errors. Further research is needed to explore in more depth the trade-offs between collective vigilance and individual accountability by relying on others to catch and correct the potentially harmful errors and avert negative outcomes. PMID:22214406

  8. Catching and correcting near misses: the collective vigilance and individual accountability trade-off.

    PubMed

    Jeffs, Lianne Patricia; Lingard, Lorelei; Berta, Whitney; Baker, G Ross

    2012-03-01

    Despite the focus on patient safety and quality health care for the last two decades, there is still limited understanding of how interprofessional interactions at an organizational or work unit level influence how clinicians perceive and respond to safety events and errors. Within the rubric of safety events, there has been a growing interest in near misses as precursors to adverse events in health care. Given the interactive nature of the variety of professionals working together in the delivery of health care, understanding how the different clinicians experience and respond to near misses in practice is important. A constructivist grounded theory approach was employed for this study which included semi-structured interviews with 24 participants in a large teaching hospital in Canada. Findings from this study provide a deeper understanding into how different clinicians experience and respond to near misses in clinical practice. This understanding indicates that collective vigilance can potentially create risk by eroding individual professional accountability through reliance on other team members to catch and correct their errors. Further research is needed to explore in more depth the trade-offs between collective vigilance and individual accountability by relying on others to catch and correct the potentially harmful errors and avert negative outcomes.

  9. Group size effect on vigilance: evidence from Tibetan gazelle in Upper Buha River, Qinghai-Tibet Plateau.

    PubMed

    Li, Zhongqiu; Jiang, Zhigang

    2008-05-01

    Tibetan gazelle Procapra picticaudata is a threatened and endemic species to the Qinghai-Tibet Plateau. With the method of group scan sampling, we observed the behaviours of males and females of the gazelle in the two summers of 2005 and 2006, in order to test the group size effect on group vigilance. We found that male gazelles were significantly more vigilant than the females at both group scan level (percentage of individuals scanning during a session) and group scan frequency (percentage of intervals with at least one individual scanning). We also found a negative correlation between group scan level and group size and a positive correlation between group scan frequency and group size, showing the group size effect on vigilance was testified in Tibetan gazelle. The predation factor might be the main driving force for the group size effect. PMID:18215472

  10. Crew Alertness Management on the Flight Deck: Cognitive and Vigilance Performance

    NASA Technical Reports Server (NTRS)

    Dinges, David F.

    1998-01-01

    This project had three broad goals: (1) to identify environmental and organismic risks to performance of long-haul cockpit crews; (2) to assess how cognitive and psychomotor vigilance performance, and subjective measures of alertness, were affected by work-rest schedules typical of long-haul cockpit crews; and (3) to determine the alertness-promoting effectiveness of behavioral and technological countermeasures to fatigue on the flight deck. During the course of the research, a number of studies were completed in cooperation with the NASA Ames Fatigue Countermeasures Program. The publications emerging from this project are listed in a bibliography in the appendix. Progress toward these goals will be summarized below according to the period in which it was accomplished.

  11. Anthrax in injecting drug users: the need for increased vigilance in the clinic.

    PubMed

    Ascough, Stephanie; Altmann, Daniel Martin

    2015-06-01

    The emergence of a previously unrecognized route of Bacillus anthracis infection over the last few years has led to concern: sporadic anthrax outbreaks among heroin users in northern Europe have demonstrated the severe pathology associated with the newly described 'injectional anthrax'. With a high case fatality rate and non-specific early symptoms, this is a novel clinical manifestation of an old disease. Lack of awareness of this syndrome among emergency room clinicians can lead to a delayed diagnosis among heroin users; indeed, for many health workers in developed countries, where infection by B. anthracis is rare, this may be the first time they have encountered anthrax infections. As the putative route of contamination of the heroin supply is potentially ongoing, it is important that clinicians and public health workers remain vigilant for early signs of injectional anthrax.

  12. A simulator study of the interaction of pilot workload with errors, vigilance, and decisions

    NASA Technical Reports Server (NTRS)

    Smith, H. P. R.

    1979-01-01

    A full mission simulation of a civil air transport scenario that had two levels of workload was used to observe the actions of the crews and the basic aircraft parameters and to record heart rates. The results showed that the number of errors was very variable among crews but the mean increased in the higher workload case. The increase in errors was not related to rise in heart rate but was associated with vigilance times as well as the days since the last flight. The recorded data also made it possible to investigate decision time and decision order. These also varied among crews and seemed related to the ability of captains to manage the resources available to them on the flight deck.

  13. Alcohol hangover effects on memory functioning and vigilance performance after an evening of binge drinking.

    PubMed

    Verster, Joris C; van Duin, Danielle; Volkerts, Edmund R; Schreuder, Antonia H C M L; Verbaten, Marinus N

    2003-04-01

    The impairing effects on memory functioning after acute alcohol intoxication in healthy volunteers and after chronic use in alcoholics are well established. However, research determining the next-morning effects of a single episode of binge drinking on memory functioning is scarce. A total of 48 healthy volunteers participated in a single-blind study comprising an evening (baseline) session, followed by a treatment administration (ethanol 1.4 g/kg or placebo), and a morning session. Memory was tested with a word-learning test (including immediate and delayed recall, and recognition). Further, a 45-min Mackworth clock test for measuring vigilance was included (parameters: number of hits and false alarms) and subjective alertness was assessed, to infer whether word-learning test findings reflect sedation or specific memory impairments. Delayed recall in the morning session was significantly worse in the alcohol group when compared to the placebo group (F(1,42)=6.0, p<0.02). In contrast, immediate recall and recognition were unimpaired in the alcohol group. In the morning session, relative to the placebo group, subjective alertness was significantly reduced in the alcohol group before and after the tests (F(1,44)=8.7, p<0.005; F(1,44)=13.3, p&<0.001, respectively). However, in the Mackworth clock test, the alcohol group and placebo group did not differ significantly in the morning session. The specific findings of impaired delayed recall show that memory retrieval processes are significantly impaired during alcohol hangover. Vigilance performance was not significantly affected, indicating that this memory impairment does not reflect sedation.

  14. Validity and sensitivity of a brief psychomotor vigilance test (PVT-B) to total and partial sleep deprivation

    NASA Astrophysics Data System (ADS)

    Basner, Mathias; Mollicone, Daniel; Dinges, David F.

    2011-12-01

    The Psychomotor Vigilance Test (PVT) objectively assesses fatigue-related changes in alertness associated with sleep loss, extended wakefulness, circadian misalignment, and time on task. The standard 10-min PVT is often considered impractical in applied contexts. To address this limitation, we developed a modified brief 3-min version of the PVT (PVT-B). The PVT-B was validated in controlled laboratory studies with 74 healthy subjects (34 female, aged 22-45 years) that participated either in a total sleep deprivation (TSD) study involving 33 h awake ( N=31 subjects) or in a partial sleep deprivation (PSD) protocol involving 5 consecutive nights of 4 h time in bed ( N=43 subjects). PVT and PVT-B were performed regularly during wakefulness. Effect sizes of 5 key PVT outcomes were larger for TSD than PSD and larger for PVT than for PVT-B for all outcomes. Effect size was largest for response speed (reciprocal response time) for both the PVT-B and the PVT in both TSD and PSD. According to Cohen's criteria, effect sizes for the PVT-B were still large (TSD) or medium to large (PSD, except for fastest 10% RT). Compared to the 70% decrease in test duration the 22.7% (range 6.9-67.8%) average decrease in effect size was deemed an acceptable trade-off between duration and sensitivity. Overall, PVT-B performance had faster response times, more false starts and fewer lapses than PVT performance (all p<0.01). After reducing the lapse threshold from 500 to 355 ms for PVT-B, mixed model ANOVAs indicated no differential sensitivity to sleep loss between PVT-B and PVT for all outcome variables (all P>0.15) but the fastest 10% response times during PSD ( P<0.001), and effect sizes increased from 1.38 to 1.49 (TSD) and 0.65 to 0.76 (PSD), respectively. In conclusion, PVT-B tracked standard 10-min PVT performance throughout both TSD and PSD, and yielded medium to large effect sizes. PVT-B may be a useful tool for assessing behavioral alertness in settings where the duration of the 10

  15. Moonlight avoidance in gerbils reveals a sophisticated interplay among time allocation, vigilance and state-dependent foraging.

    PubMed

    Kotler, Burt P; Brown, Joel; Mukherjee, Shomen; Berger-Tal, Oded; Bouskila, Amos

    2010-05-22

    Foraging animals have several tools for managing the risk of predation, and the foraging games between them and their predators. Among these, time allocation is foremost, followed by vigilance and apprehension. Together, their use influences a forager's time allocation and giving-up density (GUD) in depletable resource patches. We examined Allenby's gerbils (Gerbilus andersoni allenbyi) exploiting seed resource patches in a large vivarium under varying moon phases in the presence of a red fox (Vulpes vulpes). We measured time allocated to foraging patches electronically and GUDs from seeds left behind in resource patches. From these, we estimated handling times, attack rates and quitting harvest rates (QHRs). Gerbils displayed greater vigilance (lower attack rates) at brighter moon phases (full < wane < wax < new). Similarly, they displayed higher GUDs at brighter moon phases (wax > full > new > wane). Finally, gerbils displayed higher QHRs at new and waxing moon phases. Differences across moon phases not only reflect changing time allocation and vigilance, but changes in the state of the foragers and their marginal value of energy. Early in the lunar cycle, gerbils rely on vigilance and sacrifice state to avoid risk; later they defend state at the cost of increased time allocation; finally their state can recover as safe opportunities expand. In the predator-prey foraging game, foxes may contribute to these patterns of behaviours by modulating their own activity in response to the opportunities presented in each moon phase.

  16. The Effects of Sleep Debt on Vigilance in Young Drivers: An Education/Research Project in High Schools

    ERIC Educational Resources Information Center

    Lucidi, Fabio; Devoto, Alessandra; Bertini, Mario; Braibanti, Paride; Violani, Cristiano

    2002-01-01

    The vigilance levels of a group of 59 students were assessed in the daytime (9:00-11:00 a.m.) and again early Sunday morning (2:30-5:00 a.m.), and were then compared. Data were collected at the students' schools. The differences in performance impairment associated with different Saturday night social activities and the effect of alcohol…

  17. Detecting Threat-Related Intentional Actions of Others: Effects of Image Quality, Response Mode, and Target Cuing on Vigilance

    ERIC Educational Resources Information Center

    Parasuraman, Raja; de Visser, Ewart; Clarke, Ellen; McGarry, W. Ryan; Hussey, Elizabeth; Shaw, Tyler; Thompson, James C.

    2009-01-01

    Three experiments examined the vigilance performance of participants watching videos depicting intentional actions of an individual's hand reaching for and grasping an object--involving transporting or using either a gun or a hairdryer--in order to detect infrequent threat-related actions. Participants indicated detection of target actions either…

  18. Abrupt onset of disturbed vigilance, bilateral third nerve palsy and masturbating behaviour: a rare presentation of stroke.

    PubMed

    Mondon, Karl; Bonnaud, Isabelle; Debiais, Séverine; Brunault, Paul; Saudeau, Denis; de Toffol, Bertrand; Autret, Alain

    2007-08-01

    The clinical presentation of stroke usually includes sensory-motor impairment, cranial nerve palsies, or cognitive dysfunction. Disorders in behaviour are less frequently seen. The case of a patient with a very disturbing presentation, which included a disturbance in vigilance, bilateral third nerve palsy and masturbating behaviour, is presented. The topography of the lesions and its implications on the deficits observed are discussed.

  19. Does the Vigilance-Avoidance Gazing Behavior of Children with Separation Anxiety Disorder Change after Cognitive-Behavioral Therapy?

    ERIC Educational Resources Information Center

    In-Albon, Tina; Schneider, Silvia

    2012-01-01

    Cognitive biases are of interest in understanding the development of anxiety disorders. They also play a significant role during psychotherapy, where cognitive biases are modified in order to break the vicious cycle responsible for maintaining anxiety disorders. In a previous study, the vigilance-avoidance pattern was shown in children with…

  20. Emotional attachment security as the origin of liberal-conservative differences in vigilance to negative features of the environment.

    PubMed

    Buck, Ross

    2014-06-01

    This commentary advances the hypothesis that differences between liberal and conservative orientations noted in the target article are emotional in nature and caused by differences in attachment security: Conservatives are more vigilant to negative features of the environment because of a general sense of insecurity, whereas liberals are relatively more secure. PMID:24970430

  1. Moonlight avoidance in gerbils reveals a sophisticated interplay among time allocation, vigilance and state-dependent foraging.

    PubMed

    Kotler, Burt P; Brown, Joel; Mukherjee, Shomen; Berger-Tal, Oded; Bouskila, Amos

    2010-05-22

    Foraging animals have several tools for managing the risk of predation, and the foraging games between them and their predators. Among these, time allocation is foremost, followed by vigilance and apprehension. Together, their use influences a forager's time allocation and giving-up density (GUD) in depletable resource patches. We examined Allenby's gerbils (Gerbilus andersoni allenbyi) exploiting seed resource patches in a large vivarium under varying moon phases in the presence of a red fox (Vulpes vulpes). We measured time allocated to foraging patches electronically and GUDs from seeds left behind in resource patches. From these, we estimated handling times, attack rates and quitting harvest rates (QHRs). Gerbils displayed greater vigilance (lower attack rates) at brighter moon phases (full < wane < wax < new). Similarly, they displayed higher GUDs at brighter moon phases (wax > full > new > wane). Finally, gerbils displayed higher QHRs at new and waxing moon phases. Differences across moon phases not only reflect changing time allocation and vigilance, but changes in the state of the foragers and their marginal value of energy. Early in the lunar cycle, gerbils rely on vigilance and sacrifice state to avoid risk; later they defend state at the cost of increased time allocation; finally their state can recover as safe opportunities expand. In the predator-prey foraging game, foxes may contribute to these patterns of behaviours by modulating their own activity in response to the opportunities presented in each moon phase. PMID:20053649

  2. Moonlight avoidance in gerbils reveals a sophisticated interplay among time allocation, vigilance and state-dependent foraging

    PubMed Central

    Kotler, Burt P.; Brown, Joel; Mukherjee, Shomen; Berger-Tal, Oded; Bouskila, Amos

    2010-01-01

    Foraging animals have several tools for managing the risk of predation, and the foraging games between them and their predators. Among these, time allocation is foremost, followed by vigilance and apprehension. Together, their use influences a forager's time allocation and giving-up density (GUD) in depletable resource patches. We examined Allenby's gerbils (Gerbilus andersoni allenbyi) exploiting seed resource patches in a large vivarium under varying moon phases in the presence of a red fox (Vulpes vulpes). We measured time allocated to foraging patches electronically and GUDs from seeds left behind in resource patches. From these, we estimated handling times, attack rates and quitting harvest rates (QHRs). Gerbils displayed greater vigilance (lower attack rates) at brighter moon phases (full < wane < wax < new). Similarly, they displayed higher GUDs at brighter moon phases (wax > full > new > wane). Finally, gerbils displayed higher QHRs at new and waxing moon phases. Differences across moon phases not only reflect changing time allocation and vigilance, but changes in the state of the foragers and their marginal value of energy. Early in the lunar cycle, gerbils rely on vigilance and sacrifice state to avoid risk; later they defend state at the cost of increased time allocation; finally their state can recover as safe opportunities expand. In the predator–prey foraging game, foxes may contribute to these patterns of behaviours by modulating their own activity in response to the opportunities presented in each moon phase. PMID:20053649

  3. On the road to invariant recognition: explaining tradeoff and morph properties of cells in inferotemporal cortex using multiple-scale task-sensitive attentive learning.

    PubMed

    Grossberg, Stephen; Markowitz, Jeffrey; Cao, Yongqiang

    2011-12-01

    Visual object recognition is an essential accomplishment of advanced brains. Object recognition needs to be tolerant, or invariant, with respect to changes in object position, size, and view. In monkeys and humans, a key area for recognition is the anterior inferotemporal cortex (ITa). Recent neurophysiological data show that ITa cells with high object selectivity often have low position tolerance. We propose a neural model whose cells learn to simulate this tradeoff, as well as ITa responses to image morphs, while explaining how invariant recognition properties may arise in stages due to processes across multiple cortical areas. These processes include the cortical magnification factor, multiple receptive field sizes, and top-down attentive matching and learning properties that may be tuned by task requirements to attend to either concrete or abstract visual features with different levels of vigilance. The model predicts that data from the tradeoff and image morph tasks emerge from different levels of vigilance in the animals performing them. This result illustrates how different vigilance requirements of a task may change the course of category learning, notably the critical features that are attended and incorporated into learned category prototypes. The model outlines a path for developing an animal model of how defective vigilance control can lead to symptoms of various mental disorders, such as autism and amnesia.

  4. The Impact of Target Frequency on Intra-Individual Variability in Euthymic Bipolar Disorder: A Comparison of Two Sustained Attention Tasks.

    PubMed

    Moss, Rachel Ann; Finkelmeyer, Andreas; Robinson, Lucy J; Thompson, Jill M; Watson, Stuart; Ferrier, I Nicol; Gallagher, Peter

    2016-01-01

    Greater intra-individual variability (IIV) in reaction time (RT) on a sustained attention task has been reported in patients with bipolar disorder (BD) compared with healthy controls. However, it is unclear whether IIV is task specific, or whether it represents general cross-task impairment in BD. This study aimed to investigate whether IIV occurs in sustained attention tasks with different parameters. Twenty-two patients with BD (currently euthymic) and 17 controls completed two sustained attention tasks on different occasions: a low target frequency (~20%) Vigil continuous performance test (CPT) and a high target frequency (~70%) CPT version A-X (CPT-AX). Variability measures (individual standard deviation and coefficient of variation) were calculated per participant, and ex-Gaussian modeling was also applied. This was supplemented by Vincentile analysis to characterize RT distributions. Results indicated that participants (patients and controls) were generally slower and more variable when completing the Vigil CPT compared with CPT-AX. Significant group differences were also observed in the Vigil CPT, with euthymic BD patients being more variable than controls. This result suggests that IIV in BD demonstrates some degree of task specificity. Further research should incorporate analysis of additional RT distributional models (drift diffusion and fast Fourier transform) to fully characterize the pattern of IIV in BD, as well as its relationship to cognitive processes. PMID:27378954

  5. The Impact of Target Frequency on Intra-Individual Variability in Euthymic Bipolar Disorder: A Comparison of Two Sustained Attention Tasks

    PubMed Central

    Moss, Rachel Ann; Finkelmeyer, Andreas; Robinson, Lucy J.; Thompson, Jill M.; Watson, Stuart; Ferrier, I. Nicol; Gallagher, Peter

    2016-01-01

    Greater intra-individual variability (IIV) in reaction time (RT) on a sustained attention task has been reported in patients with bipolar disorder (BD) compared with healthy controls. However, it is unclear whether IIV is task specific, or whether it represents general cross-task impairment in BD. This study aimed to investigate whether IIV occurs in sustained attention tasks with different parameters. Twenty-two patients with BD (currently euthymic) and 17 controls completed two sustained attention tasks on different occasions: a low target frequency (~20%) Vigil continuous performance test (CPT) and a high target frequency (~70%) CPT version A-X (CPT-AX). Variability measures (individual standard deviation and coefficient of variation) were calculated per participant, and ex-Gaussian modeling was also applied. This was supplemented by Vincentile analysis to characterize RT distributions. Results indicated that participants (patients and controls) were generally slower and more variable when completing the Vigil CPT compared with CPT-AX. Significant group differences were also observed in the Vigil CPT, with euthymic BD patients being more variable than controls. This result suggests that IIV in BD demonstrates some degree of task specificity. Further research should incorporate analysis of additional RT distributional models (drift diffusion and fast Fourier transform) to fully characterize the pattern of IIV in BD, as well as its relationship to cognitive processes. PMID:27378954

  6. Modeling Simple Driving Tasks with a One-Boundary Diffusion Model

    PubMed Central

    Ratcliff, Roger; Strayer, David

    2014-01-01

    A one-boundary diffusion model was applied to the data from two experiments in which subjects were performing a simple simulated driving task. In the first experiment, the same subjects were tested on two driving tasks using a PC-based driving simulator and the psychomotor vigilance test (PVT). The diffusion model fit the response time (RT) distributions for each task and individual subject well. Model parameters were found to correlate across tasks which suggests common component processes were being tapped in the three tasks. The model was also fit to a distracted driving experiment of Cooper and Strayer (2008). Results showed that distraction altered performance by affecting the rate of evidence accumulation (drift rate) and/or increasing the boundary settings. This provides an interpretation of cognitive distraction whereby conversing on a cell phone diverts attention from the normal accumulation of information in the driving environment. PMID:24297620

  7. The scent of wolves: pyrazine analogs induce avoidance and vigilance behaviors in prey.

    PubMed

    Osada, Kazumi; Miyazono, Sadaharu; Kashiwayanagi, Makoto

    2015-01-01

    The common gray wolf (Canis lupus) is an apex predator located at the top of the food chain in the Northern Hemisphere. It preys on rodents, rabbits, ungulates, and many other kinds of mammal. However, the behavioral evidence for, and the chemical basis of, the fear-inducing impact of wolf urine on prey are unclear. Recently, the pyrazine analogs 2, 6-dimethylpyrazine, 2, 3, 5-trimethylpyrazine and 3-ethyl-2, 5-dimethyl pyrazine were identified as kairomones in the urine of wolves. When mice were confronted with a mixture of purified pyrazine analogs, vigilance behaviors, including freezing and excitation of neurons at the accessory olfactory bulb, were markedly increased. Additionally, the odor of the pyrazine cocktail effectively suppressed the approach of deer to a feeding area, and for those close to the feeding area elicited fear-related behaviors such as the "tail-flag," "flight," and "jump" actions. In this review, we discuss the transfer of chemical information from wolf to prey through the novel kairomones identified in wolf urine and also compare the characteristics of wolf kairomones with other predator-produced kairomones that affect rodents. PMID:26500485

  8. Unconscious Vigilance: Worldview Defense Without Adaptations for Terror, Coalition, or Uncertainty Management

    PubMed Central

    Holbrook, Colin; Sousa, Paulo; Hahn-Holbrook, Jennifer

    2012-01-01

    Individuals subtly reminded of death, coalitional challenges, or feelings of uncertainty display exaggerated preferences for affirmations and against criticisms of their cultural in-groups. Terror management, coalitional psychology, and uncertainty management theories postulate this “worldview defense” effect as the output of mechanisms evolved either to allay the fear of death, foster social support, or reduce anxiety by increasing adherence to cultural values. In 4 studies, we report evidence for an alternative perspective. We argue that worldview defense owes to unconscious vigilance, a state of accentuated reactivity to affective targets (which need not relate to cultural worldviews) that follows detection of subtle alarm cues (which need not pertain to death, coalitional challenges, or uncertainty). In Studies 1 and 2, death-primed participants produced exaggerated ratings of worldview-neutral affective targets. In Studies 3 and 4, subliminal threat manipulations unrelated to death, coalitional challenges, or uncertainty evoked worldview defense. These results are discussed as they inform evolutionary interpretations of worldview defense and future investigations of the influence of unconscious alarm on judgment. PMID:21644809

  9. Eager feelings and vigilant reasons: Regulatory focus differences in judging moral wrongs.

    PubMed

    Cornwell, James F M; Higgins, E Tory

    2016-03-01

    For over a decade, moral psychologists have been actively researching the processes underlying moral judgments that are made intuitively without reference to an action's concrete harms or injustice, such as the well-known case of nonprocreative, consensual incest. We suggest that the reason some judge such scenarios as wrong (using intuitive feelings) and others do not (using deliberative reasons) is due to an important motivational distinction. Consistent with this view, across 7 studies, we demonstrate that negative judgments of such moral scenarios are more intense when processed in the promotion focus compared to the prevention focus, and that this is due to differences in whether eager (intuitive feelings) versus vigilant (deliberative reasons) means are employed in judging these moral wrongs. By examining both boundary conditions and possible underlying mechanisms for regulatory focus differences in moral judgment intensity, we expand our understanding of the differences between promotion and prevention regarding how proscriptive judgments are processed, while integrating these differences with existing theories in moral psychology.

  10. Global Scientific Vision With Local Vigilance: Renal Transplantation in Developing Countries

    PubMed Central

    Ardalan, Mohammad Reza

    2014-01-01

    Context: Renal Transplantation is the most effective treatment for patients with end-stage renal disease, which is fortunately available in the developing countries, even for poor people. Nonetheless, the way forward should be the implementation of advanced science of transplantation, allograft monitoring abilities, knowledge about the epidemiology of renal disease in any specific region, awareness about the influence of ethenic and genetic factors immunosuppressant bioavailability, and post-transplant complications all strongly affecting the patients and allograft survival. Evidence Acquisitions: In this process we searched mainly in PubMed, Web of Science and Google Scholar data bases for key words of renal allograft monitoring, post-transplant infections, renal/kidney transplantation and Iran. We followed the cross articles to follow our main idea to find a connection between modern advancement in renal allograft monitoring and our practice in developing countries. Another focus was on the special infectious and non-infection complication that do exist in specific region and need specific considerations. Results: Implementation of modern techniques of immune monitoring, allograft function, awareness about the specific infectious and non-infectious disease in each region improves the quality of renal transplantation. Conclusions: We need to combine the advance scientific vision with local vigilance to achieve the best outcome in renal allograft recipients PMID:25738120

  11. Two-year-olds are vigilant of others' non-verbal cues to credibility.

    PubMed

    Birch, Susan A J; Akmal, Nazanin; Frampton, Kristen L

    2010-03-01

    Data from three experiments provide the first evidence that children, at least as young as age two, are vigilant of others' non-verbal cues to credibility, and flexibly use these cues to facilitate learning. Experiment 1 revealed that 2- and 3-year-olds prefer to learn about objects from someone who appears, through non-verbal cues, to be confident in performing actions on those objects than from someone who appears uncertain when performing actions on those objects. Experiment 2 revealed that when 2-year-olds observe only one model perform a single action, either confidently or unconfidently, they do not use the model's level of confidence in this single instance to influence their learning. Experiment 3 revealed that 2-year-olds will use a single model's level of confidence to guide their learning if they have observed that the model has a history of being either consistently confident or consistently uncertain. These findings reveal that young children selectively alter their learning based on others' non-verbal cues of credibility, and underscore the importance of an early sensitivity to socio-cognitive cues for human learning and development. PMID:20136933

  12. Example of an investigation of an "emergent" phenomenon in addiction vigilance: the case of methylphenidate.

    PubMed

    Micallef, Joëlle; Frauger, Elisabeth; Palmaro, Aurore; Boucherie, Quentin; Lapeyre Mestre, Maryse

    2015-01-01

    Abuse of and addiction to medication are a major public health issue which is evolving fast, in particular in countries like France, one of the largest consumers of medication in Europe. As a single source of information is not generally sufficient to measure a phenomenon as difficult to apprehend as medication-related addiction, as can be seen in the case of methylphenidate, it is essential to mobilise all the tools available, here surveillance programmes developed by the French CEIP Addiction vigilance network, such as suspicious prescriptions indicating possible abuse data (OSIAP) or observatory of illegal or misused psychoactive medications (OPPIDUM), as well as the health insurance databases, and health professional sentinel networks. The latest data available on methylphenidate abuse in France suggests a stabilisation of the phenomenon, which emerged in the Provence-Alpes-Côte-d'Azur (PACA) region in southern France. It also evidences its diffusion to other regions, so that the information needs to be widely relayed, and suggests that health professionals should exercise the greatest caution in the use of this substance, and should look for early signs of its misuse. PMID:25858575

  13. The scent of wolves: pyrazine analogs induce avoidance and vigilance behaviors in prey

    PubMed Central

    Osada, Kazumi; Miyazono, Sadaharu; Kashiwayanagi, Makoto

    2015-01-01

    The common gray wolf (Canis lupus) is an apex predator located at the top of the food chain in the Northern Hemisphere. It preys on rodents, rabbits, ungulates, and many other kinds of mammal. However, the behavioral evidence for, and the chemical basis of, the fear-inducing impact of wolf urine on prey are unclear. Recently, the pyrazine analogs 2, 6-dimethylpyrazine, 2, 3, 5-trimethylpyrazine and 3-ethyl-2, 5-dimethyl pyrazine were identified as kairomones in the urine of wolves. When mice were confronted with a mixture of purified pyrazine analogs, vigilance behaviors, including freezing and excitation of neurons at the accessory olfactory bulb, were markedly increased. Additionally, the odor of the pyrazine cocktail effectively suppressed the approach of deer to a feeding area, and for those close to the feeding area elicited fear-related behaviors such as the “tail-flag,” “flight,” and “jump” actions. In this review, we discuss the transfer of chemical information from wolf to prey through the novel kairomones identified in wolf urine and also compare the characteristics of wolf kairomones with other predator-produced kairomones that affect rodents. PMID:26500485

  14. Anaphylaxis to diclofenac: nine cases reported to the Allergy Vigilance Network in France.

    PubMed

    Picaud, J; Beaudouin, E; Renaudin, J M; Pirson, F; Metz-Favre, C; Dron-Gonzalvez, M; Moneret-Vautrin, D A

    2014-10-01

    Nine cases of diclofenac hypersensitivity recorded by the Allergy Vigilance Network in France from 2002 to 2012 were studied. Data from history, symptoms, skin tests, basophil activation tests, and oral challenge (OC) were recorded. Grade 3 severe anaphylactic reactions occurred in seven cases of nine. IgE-dependent anaphylaxis was confirmed in six cases: positive intradermal tests (n = 4), a syndromic reaction during skin tests (n = 1), and one case with grade 1 reaction and negative skin tests had an anaphylactic shock to the OC. A nonimmune reaction was suspected in one case. An IgE-dependent mechanism may be the predominant cause of adverse reactions to diclofenac. Allergy skin tests must be carried out sequentially at the recommended concentrations. BATs may be helpful because they can support the diagnosis of anaphylaxis. Given the risks of a direct challenge to diclofenac, OC to aspirin should be performed first to exclude a nonimmunologic hypersensitivity to NSAIDs. Tests for specific IgEs to most frequently used NSAIDs such as diclofenac and ibuprofen are urgently needed.

  15. Circadian rhythms (temperature, heart rate, vigilance, mood) of short and long sleepers: effects of sleep deprivation.

    PubMed

    Benoit, O; Foret, J; Merle, B; Reinberg, A

    1981-01-01

    Seven long sleepers (LS) (sleep greater than or equal to 9 h) and seven short sleepers (SS) (sleep less than or equal to 7 h), aged 20 to 23 years, were selected among medical students. They measured their axillary temperature (T), heart rate (HR) and self-estimated their vigilance (V) and mood (M) every 4 h from awakening to bed time during a ten-day control span and during the two sleep deprived nights. Polygraphic sleep recordings were performed on 3 control days and recovery from 24 h (day sleep) or 36 h (night sleep) sleep deprivations. For the 4 variables (T, HR, V and M), group circadian patterns were analyzed by means of the cosinor method for the control span and after both types of sleep deprivation. The acrophases of the 4 variables clustered more in LS than in SS. The acrophases of V and M were found to be more closely related to the sleep/wake rhythm than those of T and HR. Sleep deprivation resulted in a large change of the circadian rhythms in LS but had little effect in SS as indicated by the non detection of most acrophases in LS and the persistence of such acrophases in SS. This difference might be explained by the large interindividual variability of changes induced by the sleep deprivation in LS. Moreover, day sleep recovery was more disturbed in LS than in SS. PMID:7327054

  16. Biological Rhythms Modelisation of Vigilance and Sleep in Microgravity State with COSINOR and Volterra's Kernels Methods

    NASA Astrophysics Data System (ADS)

    Gaudeua de Gerlicz, C.; Golding, J. G.; Bobola, Ph.; Moutarde, C.; Naji, S.

    2008-06-01

    The spaceflight under microgravity cause basically biological and physiological imbalance in human being. Lot of study has been yet release on this topic especially about sleep disturbances and on the circadian rhythms (alternation vigilance-sleep, body, temperature...). Factors like space motion sickness, noise, or excitement can cause severe sleep disturbances. For a stay of longer than four months in space, gradual increases in the planned duration of sleep were reported. [1] The average sleep in orbit was more than 1.5 hours shorter than the during control periods on earth, where sleep averaged 7.9 hours. [2] Alertness and calmness were unregistered yield clear circadian pattern of 24h but with a phase delay of 4h.The calmness showed a biphasic component (12h) mean sleep duration was 6.4 structured by 3-5 non REM/REM cycles. Modelisations of neurophysiologic mechanisms of stress and interactions between various physiological and psychological variables of rhythms have can be yet release with the COSINOR method. [3

  17. Automatic vigilance for negative words in lexical decision and naming: comment on Larsen, Mercer, and Balota (2006).

    PubMed

    Estes, Zachary; Adelman, James S

    2008-08-01

    An automatic vigilance hypothesis states that humans preferentially attend to negative stimuli, and this attention to negative valence disrupts the processing of other stimulus properties. Thus, negative words typically elicit slower color naming, word naming, and lexical decisions than neutral or positive words. Larsen, Mercer, and Balota analyzed the stimuli from 32 published studies, and they found that word valence was confounded with several lexical factors known to affect word recognition. Indeed, with these lexical factors covaried out, Larsen et al. found no evidence of automatic vigilance. The authors report a more sensitive analysis of 1011 words. Results revealed a small but reliable valence effect, such that negative words (e.g., "shark") elicit slower lexical decisions and naming than positive words (e.g., "beach"). Moreover, the relation between valence and recognition was categorical rather than linear; the extremity of a word's valence did not affect its recognition. This valence effect was not attributable to word length, frequency, orthographic neighborhood size, contextual diversity, first phoneme, or arousal. Thus, the present analysis provides the most powerful demonstration of automatic vigilance to date. PMID:18729575

  18. Spanish version of the Pain Vigilance and Awareness Questionnaire: psychometric properties in a sample of women with fibromyalgia.

    PubMed

    Pilar Martínez, M; Miró, Elena; Sánchez, Ana I; Lami, María J; Prados, Germán; Ávila, Daniela

    2015-01-08

    Excessive attention to pain is a common psychological characteristic among people who suffer from chronic pain. The Pain Vigilance and Awareness Questionnaire (PVAQ) is an internationally accepted tool to assess this feature, although there is no validated version of this measure for Spanish people with fibromyalgia. Since this pain syndrome mainly affects women, the aim of this study was to determine the psychometric properties of the PVAQ in Spanish women with fibromyalgia. A group of 242 women diagnosed with fibromyalgia aged between 20 and 66 years participated in the study. The goodness of fit of several structures of the PVAQ reported in previous studies was compared via confirmatory factor analysis. A two-factor solution (active vigilance and passive awareness) of the 9-item shortened version (PVAQ-9) was identified as the most appropriate (RMSEA = .08, NNFI = .96, CFI = .97, GFI = .87). It showed good reliability (internal consistency α = .82), convergent validity and divergent validity (p < .01). The optimal cutoff point for identifying fibromyalgia women with worse daily functioning was a score of 24.5, with a sensitivity of .71 and a specificity of .75. The relevance of vigilance to pain for clinical research in fibromyalgia is discussed.

  19. Exploring the evolution of a trade-off between vigilance and foraging in group-living organisms.

    PubMed

    Olson, Randal S; Haley, Patrick B; Dyer, Fred C; Adami, Christoph

    2015-09-01

    Even though grouping behaviour has been actively studied for over a century, the relative importance of the numerous proposed fitness benefits of grouping remain unclear. We use a digital model of evolving prey under simulated predation to directly explore the evolution of gregarious foraging behaviour according to one such benefit, the 'many eyes' hypothesis. According to this hypothesis, collective vigilance allows prey in large groups to detect predators more efficiently by making alarm signals or behavioural cues to each other, thereby allowing individuals within the group to spend more time foraging. Here, we find that collective vigilance is sufficient to select for gregarious foraging behaviour as long there is not a direct cost for grouping (e.g. competition for limited food resources), even when controlling for confounding factors such as the dilution effect. Furthermore, we explore the role of the genetic relatedness and reproductive strategy of the prey and find that highly related groups of prey with a semelparous reproductive strategy are the most likely to evolve gregarious foraging behaviour mediated by the benefit of vigilance. These findings, combined with earlier studies with evolving digital organisms, further sharpen our understanding of the factors favouring grouping behaviour. PMID:26473039

  20. Exploring the evolution of a trade-off between vigilance and foraging in group-living organisms.

    PubMed

    Olson, Randal S; Haley, Patrick B; Dyer, Fred C; Adami, Christoph

    2015-09-01

    Even though grouping behaviour has been actively studied for over a century, the relative importance of the numerous proposed fitness benefits of grouping remain unclear. We use a digital model of evolving prey under simulated predation to directly explore the evolution of gregarious foraging behaviour according to one such benefit, the 'many eyes' hypothesis. According to this hypothesis, collective vigilance allows prey in large groups to detect predators more efficiently by making alarm signals or behavioural cues to each other, thereby allowing individuals within the group to spend more time foraging. Here, we find that collective vigilance is sufficient to select for gregarious foraging behaviour as long there is not a direct cost for grouping (e.g. competition for limited food resources), even when controlling for confounding factors such as the dilution effect. Furthermore, we explore the role of the genetic relatedness and reproductive strategy of the prey and find that highly related groups of prey with a semelparous reproductive strategy are the most likely to evolve gregarious foraging behaviour mediated by the benefit of vigilance. These findings, combined with earlier studies with evolving digital organisms, further sharpen our understanding of the factors favouring grouping behaviour.

  1. Exploring the evolution of a trade-off between vigilance and foraging in group-living organisms

    PubMed Central

    Olson, Randal S.; Haley, Patrick B.; Dyer, Fred C.; Adami, Christoph

    2015-01-01

    Even though grouping behaviour has been actively studied for over a century, the relative importance of the numerous proposed fitness benefits of grouping remain unclear. We use a digital model of evolving prey under simulated predation to directly explore the evolution of gregarious foraging behaviour according to one such benefit, the ‘many eyes’ hypothesis. According to this hypothesis, collective vigilance allows prey in large groups to detect predators more efficiently by making alarm signals or behavioural cues to each other, thereby allowing individuals within the group to spend more time foraging. Here, we find that collective vigilance is sufficient to select for gregarious foraging behaviour as long there is not a direct cost for grouping (e.g. competition for limited food resources), even when controlling for confounding factors such as the dilution effect. Furthermore, we explore the role of the genetic relatedness and reproductive strategy of the prey and find that highly related groups of prey with a semelparous reproductive strategy are the most likely to evolve gregarious foraging behaviour mediated by the benefit of vigilance. These findings, combined with earlier studies with evolving digital organisms, further sharpen our understanding of the factors favouring grouping behaviour. PMID:26473039

  2. A Vehicle Active Safety Model: Vehicle Speed Control Based on Driver Vigilance Detection Using Wearable EEG and Sparse Representation.

    PubMed

    Zhang, Zutao; Luo, Dianyuan; Rasim, Yagubov; Li, Yanjun; Meng, Guanjun; Xu, Jian; Wang, Chunbai

    2016-01-01

    In this paper, we present a vehicle active safety model for vehicle speed control based on driver vigilance detection using low-cost, comfortable, wearable electroencephalographic (EEG) sensors and sparse representation. The proposed system consists of three main steps, namely wireless wearable EEG collection, driver vigilance detection, and vehicle speed control strategy. First of all, a homemade low-cost comfortable wearable brain-computer interface (BCI) system with eight channels is designed for collecting the driver's EEG signal. Second, wavelet de-noising and down-sample algorithms are utilized to enhance the quality of EEG data, and Fast Fourier Transformation (FFT) is adopted to extract the EEG power spectrum density (PSD). In this step, sparse representation classification combined with k-singular value decomposition (KSVD) is firstly introduced in PSD to estimate the driver's vigilance level. Finally, a novel safety strategy of vehicle speed control, which controls the electronic throttle opening and automatic braking after driver fatigue detection using the above method, is presented to avoid serious collisions and traffic accidents. The simulation and practical testing results demonstrate the feasibility of the vehicle active safety model. PMID:26907278

  3. A Vehicle Active Safety Model: Vehicle Speed Control Based on Driver Vigilance Detection Using Wearable EEG and Sparse Representation

    PubMed Central

    Zhang, Zutao; Luo, Dianyuan; Rasim, Yagubov; Li, Yanjun; Meng, Guanjun; Xu, Jian; Wang, Chunbai

    2016-01-01

    In this paper, we present a vehicle active safety model for vehicle speed control based on driver vigilance detection using low-cost, comfortable, wearable electroencephalographic (EEG) sensors and sparse representation. The proposed system consists of three main steps, namely wireless wearable EEG collection, driver vigilance detection, and vehicle speed control strategy. First of all, a homemade low-cost comfortable wearable brain-computer interface (BCI) system with eight channels is designed for collecting the driver’s EEG signal. Second, wavelet de-noising and down-sample algorithms are utilized to enhance the quality of EEG data, and Fast Fourier Transformation (FFT) is adopted to extract the EEG power spectrum density (PSD). In this step, sparse representation classification combined with k-singular value decomposition (KSVD) is firstly introduced in PSD to estimate the driver’s vigilance level . Finally, a novel safety strategy of vehicle speed control, which controls the electronic throttle opening and automatic braking after driver fatigue detection using the above method, is presented to avoid serious collisions and traffic accidents. The simulation and practical testing results demonstrate the feasibility of the vehicle active safety model. PMID:26907278

  4. Diffusion model for one-choice reaction-time tasks and the cognitive effects of sleep deprivation.

    PubMed

    Ratcliff, Roger; Van Dongen, Hans P A

    2011-07-01

    One-choice reaction-time (RT) tasks are used in many domains, including assessments of motor vehicle driving and assessments of the cognitive/behavioral consequences of sleep deprivation. In such tasks, subjects are asked to respond when they detect the onset of a stimulus; the dependent variable is RT. We present a cognitive model for one-choice RT tasks that uses a one-boundary diffusion process to represent the accumulation of stimulus information. When the accumulated evidence reaches a decision criterion, a response is initiated. This model is distinct in accounting for the RT distributions observed for one-choice RT tasks, which can have long tails that have not been accurately captured by earlier cognitive modeling approaches. We show that the model explains performance on a brightness-detection task (a "simple RT task") and on a psychomotor vigilance test. The latter is used extensively to examine the clinical and behavioral effects of sleep deprivation. For the brightness-detection task, the model explains the behavior of RT distributions as a function of brightness. For the psychomotor vigilance test, it accounts for lapses in performance under conditions of sleep deprivation and for changes in the shapes of RT distributions over the course of sleep deprivation. The model also successfully maps the rate of accumulation of stimulus information onto independently derived predictions of alertness. The model is a unified, mechanistic account of one-choice RT under conditions of sleep deprivation. PMID:21690336

  5. Heart rate variability and cognitive processing: The autonomic response to task demands.

    PubMed

    Luque-Casado, Antonio; Perales, José C; Cárdenas, David; Sanabria, Daniel

    2016-01-01

    This study investigated variations in heart rate variability (HRV) as a function of cognitive demands. Participants completed an execution condition including the psychomotor vigilance task, a working memory task and a duration discrimination task. The control condition consisted of oddball versions (participants had to detect the rare event) of the tasks from the execution condition, designed to control for the effect of the task parameters (stimulus duration and stimulus rate) on HRV. The NASA-TLX questionnaire was used as a subjective measure of cognitive workload across tasks and conditions. Three major findings emerged from this study. First, HRV varied as a function of task demands (with the lowest values in the working memory task). Second, and crucially, we found similar HRV values when comparing each of the tasks with its oddball control equivalent, and a significant decrement in HRV as a function of time-on-task. Finally, the NASA-TLX results showed larger cognitive workload in the execution condition than in the oddball control condition, and scores variations as a function of task. Taken together, our results suggest that HRV is highly sensitive to overall demands of sustained attention over and above the influence of other cognitive processes suggested by previous literature. In addition, our study highlights a potential dissociation between objective and subjective measures of mental workload, with important implications in applied settings.

  6. AAVPG: A vigilant vector where transgene expression is induced by p53

    SciTech Connect

    Bajgelman, Marcio C.; Medrano, Ruan F.V.; Carvalho, Anna Carolina P.V.; Strauss, Bryan E.

    2013-12-15

    Using p53 to drive transgene expression from viral vectors may provide on demand expression in response to physiologic stress, such as hypoxia or DNA damage. Here we introduce AAVPG, an adeno-associated viral (AAV) vector where a p53-responsive promoter, termed PG, is used to control transgene expression. In vitro assays show that expression from the AAVPG-luc vector was induced specifically in the presence of functional p53 (1038±202 fold increase, p<0.001). The AAVPG-luc vector was an effective biosensor of p53 activation in response to hypoxia (4.48±0.6 fold increase in the presence of 250 µM CoCl{sub 2}, p<0.001) and biomechanical stress (2.53±0.4 fold increase with stretching, p<0.05). In vivo, the vigilant nature of the AAVPG-luc vector was revealed after treatment of tumor-bearing mice with doxorubicin (pre-treatment, 3.4×10{sup 5}±0.43×10{sup 5} photons/s; post-treatment, 6.6×10{sup 5}±2.1×10{sup 5} photons/s, p<0.05). These results indicate that the AAVPG vector is an interesting option for detecting p53 activity both in vitro and in vivo. - Highlights: • AAV vector where transgene expression is controlled by the tumor suppressor p53. • The new vector, AAVPG, shown to function as a biosensor of p53 activity, in vitro and in vivo. • The p53 activity monitored by the AAVPG vector is relevant to cancer and other diseases. • AAVPG reporter gene expression was activated upon DNA damage, hypoxia and mechanical stress.

  7. Vigilance states, EEG spectra, and cortical temperature in the guinea pig.

    PubMed

    Tobler, I; Franken, P; Jaggi, K

    1993-06-01

    Vigilance states, electroencephalogram (EEG) power spectra (0.25-25.0 Hz), and cortical temperature (TCRT) were obtained in nine guinea pigs for 24 h in a 12:12-h light-dark (LD 12:12) schedule. Sleep was markedly polyphasic and fragmented and amounted to 32% of recording time, which is a low value compared with sleep in other rodents. There was 6.8% more sleep in the light period than in the dark period. EEG power density in non-rapid eye movement (NREM) sleep showed no significant temporal trend within the light or the dark period. The homeostatic aspects of sleep regulation, as proposed in the two-process model, can account for the slow-wave activity (SWA) pattern also in the guinea pig: The small 24-h amplitude of the sleep-wakefulness pattern resulted in a small, 12% decline of SWA within the light period. In contrast to more distinctly nocturnal rodents, SWA in the dark period was not higher than in the light period. TCRT showed no difference between the light and the dark period. TCRT in REM sleep and waking was higher than TCRT in NREM sleep. TCRT increased after the transition from NREM sleep to either REM sleep or waking, and decreased in the last minute before the transition and after the transition from waking to NREM sleep. Motor activity measured in six animals for 11 days in constant darkness showed no apparent rhythm in three animals and a significant circadian rhythm in three others. Our data support the notion that guinea pigs exhibit only a weak circadian rest-activity rhythm. PMID:8322965

  8. A new likelihood ratio metric for the psychomotor vigilance test and its sensitivity to sleep loss.

    PubMed

    Basner, Mathias; Mcguire, Sarah; Goel, Namni; Rao, Hengyi; Dinges, David F

    2015-12-01

    The Psychomotor Vigilance Test (PVT) is a widely used assay of behavioural alertness sensitive to the effects of sleep loss and circadian misalignment. However, there is currently no accepted PVT composite outcome metric that captures response slowing, attentional lapses and compensatory premature reactions observed typically in sleep-deprived subjects. We developed a novel likelihood ratio metric (LRM) based on relative frequency distributions in 50 categories of reaction times (RT) and false starts in alert and sleep-deprived subjects (acute total sleep deprivation: n = 31 subjects). The LRM had the largest effect size both in a 33-h total sleep deprivation protocol [1.96; 95% confidence interval (CI): 1.61-2.44; followed by response speed 1/RT, effect size 1.93, 95% CI: 1.55-2.65] and in a chronic partial sleep restriction protocol (1.22; 95% CI: 0.96-1.59; followed by response speed 1/RT, effect size 1.21, 95% CI: 0.94-1.59; 5 nights at 4 h sleep per night; n = 43 subjects). LRM scores correlated highly with response speed (R(2 ) = 0.986), and less well with five other common PVT outcome metrics (R(2 ) = 0.111-0.886). In conclusion, the new LRM is a sensitive PVT outcome metric with high statistical power that takes subtle sleep loss-related changes in the distribution of reaction times (including false starts) into account, is not prone to outliers, does not require baseline data and can be calculated and interpreted easily. Congruence between LRM and PVT response speed and their similar effect size rankings support the use of response speed as the primary, most sensitive and most parsimonious standard PVT outcome metric for determining neurobehavioural deficits from sleep loss. PMID:26118830

  9. A resource-control account of sustained attention: evidence from mind-wandering and vigilance paradigms.

    PubMed

    Thomson, David R; Besner, Derek; Smilek, Daniel

    2015-01-01

    Staying attentive is challenging enough when carrying out everyday tasks, such as reading or sitting through a lecture, and failures to do so can be frustrating and inconvenient. However, such lapses may even be life threatening, for example, if a pilot fails to monitor an oil-pressure gauge or if a long-haul truck driver fails to notice a car in his or her blind spot. Here, we explore two explanations of sustained-attention lapses. By one account, task monotony leads to an increasing preoccupation with internal thought (i.e., mind wandering). By another, task demands result in the depletion of information-processing resources that are needed to perform the task. A review of the sustained-attention literature suggests that neither theory, on its own, adequately explains the full range of findings. We propose a novel framework to explain why attention lapses as a function of time-on-task by combining aspects of two different theories of mind wandering: attentional resource (Smallwood & Schooler, 2006) and control failure (McVay & Kane, 2010). We then use our "resource-control" theory to explain performance decrements in sustained-attention tasks. We end by making some explicit predictions regarding mind wandering in general and sustained-attention performance in particular. PMID:25910383

  10. Cognitive Fatigue Influences Time-On-Task during Bodyweight Resistance Training Exercise

    PubMed Central

    Head, James R.; Tenan, Matthew S.; Tweedell, Andrew J.; Price, Thomas F.; LaFiandra, Michael E.; Helton, William S.

    2016-01-01

    Prior investigations have shown measurable performance impairments on continuous physical performance tasks when preceded by a cognitively fatiguing task. However, the effect of cognitive fatigue on bodyweight resistance training exercise task performance is unknown. In the current investigation 18 amateur athletes completed a full body exercise task preceded by either a cognitive fatiguing or control intervention. In a randomized repeated measure design, each participant completed the same exercise task preceded by a 52 min cognitively fatiguing intervention (vigilance) or control intervention (video). Data collection sessions were separated by 1 week. Participants rated the fatigue intervention with a significantly higher workload compared to the control intervention (p < 0.001). Additionally, participants self-reported significantly greater energetic arousal for cognitively fatiguing task (p = 0.02). Cognitive fatigue did not significantly impact number of repetitions completed during the exercise task (p = 0.77); however, when cognitively fatigued, participants had decreased percent time-on-task (57%) relative to the no fatigue condition (60%; p = 0.04). RPE significantly changed over time (p < 0.001), but failed to show significant differences between the cognitive fatigue intervention and control intervention (p > 0.05). There was no statistical difference for heart rate or metabolic expenditure as a function of fatigue intervention during exercise. Cognitively fatigued athletes have decreased time-on-task in bodyweight resistance training exercise tasks.

  11. Cognitive Fatigue Influences Time-On-Task during Bodyweight Resistance Training Exercise

    PubMed Central

    Head, James R.; Tenan, Matthew S.; Tweedell, Andrew J.; Price, Thomas F.; LaFiandra, Michael E.; Helton, William S.

    2016-01-01

    Prior investigations have shown measurable performance impairments on continuous physical performance tasks when preceded by a cognitively fatiguing task. However, the effect of cognitive fatigue on bodyweight resistance training exercise task performance is unknown. In the current investigation 18 amateur athletes completed a full body exercise task preceded by either a cognitive fatiguing or control intervention. In a randomized repeated measure design, each participant completed the same exercise task preceded by a 52 min cognitively fatiguing intervention (vigilance) or control intervention (video). Data collection sessions were separated by 1 week. Participants rated the fatigue intervention with a significantly higher workload compared to the control intervention (p < 0.001). Additionally, participants self-reported significantly greater energetic arousal for cognitively fatiguing task (p = 0.02). Cognitive fatigue did not significantly impact number of repetitions completed during the exercise task (p = 0.77); however, when cognitively fatigued, participants had decreased percent time-on-task (57%) relative to the no fatigue condition (60%; p = 0.04). RPE significantly changed over time (p < 0.001), but failed to show significant differences between the cognitive fatigue intervention and control intervention (p > 0.05). There was no statistical difference for heart rate or metabolic expenditure as a function of fatigue intervention during exercise. Cognitively fatigued athletes have decreased time-on-task in bodyweight resistance training exercise tasks. PMID:27635122

  12. Cognitive Fatigue Influences Time-On-Task during Bodyweight Resistance Training Exercise.

    PubMed

    Head, James R; Tenan, Matthew S; Tweedell, Andrew J; Price, Thomas F; LaFiandra, Michael E; Helton, William S

    2016-01-01

    Prior investigations have shown measurable performance impairments on continuous physical performance tasks when preceded by a cognitively fatiguing task. However, the effect of cognitive fatigue on bodyweight resistance training exercise task performance is unknown. In the current investigation 18 amateur athletes completed a full body exercise task preceded by either a cognitive fatiguing or control intervention. In a randomized repeated measure design, each participant completed the same exercise task preceded by a 52 min cognitively fatiguing intervention (vigilance) or control intervention (video). Data collection sessions were separated by 1 week. Participants rated the fatigue intervention with a significantly higher workload compared to the control intervention (p < 0.001). Additionally, participants self-reported significantly greater energetic arousal for cognitively fatiguing task (p = 0.02). Cognitive fatigue did not significantly impact number of repetitions completed during the exercise task (p = 0.77); however, when cognitively fatigued, participants had decreased percent time-on-task (57%) relative to the no fatigue condition (60%; p = 0.04). RPE significantly changed over time (p < 0.001), but failed to show significant differences between the cognitive fatigue intervention and control intervention (p > 0.05). There was no statistical difference for heart rate or metabolic expenditure as a function of fatigue intervention during exercise. Cognitively fatigued athletes have decreased time-on-task in bodyweight resistance training exercise tasks. PMID:27635122

  13. Quantitative EEG Monitoring of Vigilance: Effects of Sleep Deprivation, Circadian Phase and Sympathetic Activation

    NASA Technical Reports Server (NTRS)

    Dijk, Derk-Jan

    1999-01-01

    Shuttle astronauts typically sleep only 6 to 6.5 hours per day while in orbit. This sleep loss is related to recurrent sleep cycle shifting--due to mission-dependent orbital mechanics and mission duration requirements-- and associated circadian displacement of sleep, the operational demands of space flight, noise and space motion sickness. Such sleep schedules are known to produce poor subjective sleep quality, daytime sleepiness, reduced attention, negative mood, slower reaction times, and impaired daytime alertness. Countermeasures to allow crew members to obtain an adequate amount of sleep and maintain adequate levels of neurobehavioral performance are being developed and investigated. However, it is necessary to develop methods that allow effective and attainable in-flight monitoring of vigilance to evaluate the effectiveness of these countermeasures and to detect and predict online critical decrements in alertness/performance. There is growing evidence to indicate that sleep loss and associated decrements in neurobehavioral function are reflected in the spectral composition of the electroencephalogram (EEG) during wakefulness as well as in the incidence of slow eye movements recorded by the electro-oculogram (EOG). Further-more, our preliminary data indicated that these changes in the EEG during wakefulness are more pronounced when subjects are in a supine posture, which mimics some of the physiologic effects of microgravity. Therefore, we evaluate the following hypotheses: (1) that during a 40-hour period of wakefulness (i.e., one night of total sleep deprivation) neurobehavioral function deteriorates, the incidence of slow eye-movements and EEG power density in the theta frequencies increases especially in frontal areas of the brain; (2) that the sleep deprivation induced deterioration of neurobehavioral function and changes in the incidence of slow eye movements and the spectral composition of the EEG are more pronounced when subjects are in a supine

  14. Local properties of vigilance states: EMD analysis of EEG signals during sleep-waking states of freely moving rats.

    PubMed

    Kumar, Rupesh; Ramaswamy, Ram; Nath Mallick, Birendra

    2013-01-01

    Understanding the inherent dynamics of the EEG associated to sleep-waking can provide insights into its basic neural regulation. By characterizing the local properties of the EEG using power spectrum, empirical mode decomposition (EMD) and Hilbert-spectral analysis, we can examine the dynamics over a range of time-scales. We analyzed rat EEG during wake, NREMS and REMS using these methods. The average instantaneous phase, power spectral density (PSD) of intrinsic mode functions (IMFs) and the energy content in various frequency bands show characteristic changes in each of the vigilance states. The 2nd and 7th IMFs show changes in PSD for wake and REMS, suggesting that those modes may carry wake- and REMS-associated cognitive, conscious and behavior-specific information of an individual even though the EEG may appear similar. The energy content in θ2 (6 Hz-9 Hz) band of the 1st IMF for REMS is larger than that of wake. The decrease in the phase function of IMFs from wake to REMS to NREMS indicates decrease of the mean frequency in these states, respectively. The rate of information processing in waking state is more in the time scale described by the first three IMFs than in REMS state. However, for IMF5-IMF7, the rate is more for REMS than that for wake. We obtained Hilbert-Huang spectral entropy, which is a suitable measure of information processing in each of these state-specific EEG. It is possible to evaluate the complex dynamics of the EEG in each of the vigilance states by applying measures based on EMD and Hilbert-transform. Our results suggest that the EMD based nonlinear measures of the EEG can provide useful estimates of the information possessed by various oscillations associated with the vigilance states. Further, the EMD-based spectral measures may have implications in understanding anatamo-physiological correlates of sleep-waking behavior and clinical diagnosis of sleep-pathology. PMID:24167606

  15. Sex-Related Differences in the Trade-Off between Foraging and Vigilance in a Granivorous Forager

    PubMed Central

    Powolny, Thibaut; Bretagnolle, Vincent; Aguilar, Astrid; Eraud, Cyril

    2014-01-01

    The relationship between intake rate and food density can provide the foundation for models that predict the spatiotemporal distribution of organisms across a range of resource densities. The functional response, describing the relationship between resource density and intake rate is often interpreted mechanistically as the relationships between times spend searching and handling. While several functional response models incorporate anti-predator vigilance (defined here as an interruption of feeding or some other activity to visually scan the environment, directed mainly towards detecting potential predators), the impacts of environmental factors influencing directly anti-predator vigilance remains unclear. We examined the combined effects of different scenarios of predation risk and food density on time allocation between foraging and anti-predator vigilance in a granivorous species. We experimentally exposed Skylarks to various cover heights and seed densities, and measured individual time budget and pecking and intake rates. Our results indicated that time devoted to different activities varied as a function of both seed density and cover height. Foraging time increased with seed density for all cover heights. Conversely, an increased cover height resulted in a decreased foraging time. Contrary to males, the decreased proportion of time spent foraging did not translate into a foraging disadvantage for females. When vegetation height was higher, females maintained similar pecking and intake rates compared to intermediate levels, while males consistently decreased their energy gain. This difference in anti-predator responses suggests a sexually mediated strategy in the food-safety trade-off: when resource density is high a females would adopt a camouflage strategy while an escape strategy would be adopted by males. In other words, males would leave risky-areas, whereas females would stay when resource density is high. Our results suggest that increased predation

  16. Local Properties of Vigilance States: EMD Analysis of EEG Signals during Sleep-Waking States of Freely Moving Rats

    PubMed Central

    Kumar, Rupesh; Ramaswamy, Ram; Nath Mallick, Birendra

    2013-01-01

    Understanding the inherent dynamics of the EEG associated to sleep-waking can provide insights into its basic neural regulation. By characterizing the local properties of the EEG using power spectrum, empirical mode decomposition (EMD) and Hilbert-spectral analysis, we can examine the dynamics over a range of time-scales. We analyzed rat EEG during wake, NREMS and REMS using these methods. The average instantaneous phase, power spectral density (PSD) of intrinsic mode functions (IMFs) and the energy content in various frequency bands show characteristic changes in each of the vigilance states. The 2nd and 7th IMFs show changes in PSD for wake and REMS, suggesting that those modes may carry wake- and REMS-associated cognitive, conscious and behavior-specific information of an individual even though the EEG may appear similar. The energy content in θ2 (6Hz-9Hz) band of the 1st IMF for REMS is larger than that of wake. The decrease in the phase function of IMFs from wake to REMS to NREMS indicates decrease of the mean frequency in these states, respectively. The rate of information processing in waking state is more in the time scale described by the first three IMFs than in REMS state. However, for IMF5-IMF7, the rate is more for REMS than that for wake. We obtained Hilbert-Huang spectral entropy, which is a suitable measure of information processing in each of these state-specific EEG. It is possible to evaluate the complex dynamics of the EEG in each of the vigilance states by applying measures based on EMD and Hilbert-transform. Our results suggest that the EMD based nonlinear measures of the EEG can provide useful estimates of the information possessed by various oscillations associated with the vigilance states. Further, the EMD-based spectral measures may have implications in understanding anatamo-physiological correlates of sleep-waking behavior and clinical diagnosis of sleep-pathology. PMID:24167606

  17. [Like Moses' staff: pathological inheritance as an argument for medical vigilance of consanguine marriage in Mexico, 1870-1900].

    PubMed

    Soriano, Fabricio González

    2009-01-01

    This paper analyzes the discussions in the field of legal medicine in Mexico about the prudence of regulations concerning intermarriage that were decreed in the civil codes for the Federal District of 1871 and 1884. It shows that the heated debate forced the authors of the regulations to struggle for the need for medical vigilance of marriages between relatives, as a preventive measure sustained in a nihilistic vision of the pathological inheritance. The paper concludes by proposing a philosophical analysis that abandons the old fields of the "external" and the "internal".

  18. Recalling academic tasks

    NASA Astrophysics Data System (ADS)

    Draper, Franklin Gno

    This study was focused on what students remembered about five middle school science tasks when they were juniors and seniors in high school. Descriptions of the five tasks were reconstructed from available artifacts and teachers' records, notes and recollections. Three of the five tasks were "authentic" in the sense that students were asked to duplicate the decisions practitioners make in the adult world. The other two tasks were more typical school tasks involving note taking and preparation for a quiz. All five tasks, however, involved use of computers. Students were interviewed to examine what and how well they recalled the tasks and what forms or patterns of recall existed. Analysis of their responses indicated that different kinds of tasks produced different levels of recall. Authentically situated tasks were remembered much better than routine school tasks. Further, authentic tasks centered on design elements were recalled better than those for which design was not as pivotal. Patterns of recall indicated that participants most often recalled the decisions they made, the scenarios of the authentically situated tasks, the consequences of their tasks and the social contexts of the classroom. Task events, in other words, appeared to form a framework upon which students constructed stories of the tasks. The more salient the events, the richer the story, the deeper and more detailed the recall of the task. Thus, authentic tasks appeared to lend themselves to creating stories better than regular school tasks and therefore such tasks were recalled better. Implications of these patterns of recall are discussed with respect to issues of school learning and assessment.

  19. Mean fecal glucocorticoid metabolites are associated with vigilance, whereas immediate cortisol levels better reflect acute anti-predator responses in meerkats.

    PubMed

    Voellmy, Irene K; Goncalves, Ines Braga; Barrette, Marie-France; Monfort, Steven L; Manser, Marta B

    2014-11-01

    Adrenal hormones likely affect anti-predator behavior in animals. With experimental field studies, we first investigated associations between mean fecal glucocorticoid metabolite (fGC) excretion and vigilance and with behavioral responses to alarm call playbacks in free-ranging meerkats (Suricata suricatta). We then tested how vigilance and behavioral responses to alarm call playbacks were affected in individuals administered exogenous cortisol. We found a positive association between mean fGC concentrations and vigilance behavior, but no relationship with the intensity of behavioral responses to alarm calls. However, in response to alarm call playbacks, individuals administered cortisol took slightly longer to resume foraging than control individuals treated with saline solution. Vigilance behavior, which occurs in the presence and absence of dangerous stimuli, serves to detect and avoid potential dangers, whereas responses to alarm calls serve to avoid immediate predation. Our data show that mean fGC excretion in meerkats was associated with vigilance, as a re-occurring anti-predator behavior over long time periods, and experimentally induced elevations of plasma cortisol affected the response to immediate threats. Together, our results indicate an association between the two types of anti-predator behavior and glucocorticoids, but that the underlying mechanisms may differ. Our study emphasizes the need to consider appropriate measures of adrenal activity specific to different contexts when assessing links between stress physiology and different anti-predator behaviors.

  20. Mean fecal glucocorticoid metabolites are associated with vigilance, whereas immediate cortisol levels better reflect acute anti-predator responses in meerkats.

    PubMed

    Voellmy, Irene K; Goncalves, Ines Braga; Barrette, Marie-France; Monfort, Steven L; Manser, Marta B

    2014-11-01

    Adrenal hormones likely affect anti-predator behavior in animals. With experimental field studies, we first investigated associations between mean fecal glucocorticoid metabolite (fGC) excretion and vigilance and with behavioral responses to alarm call playbacks in free-ranging meerkats (Suricata suricatta). We then tested how vigilance and behavioral responses to alarm call playbacks were affected in individuals administered exogenous cortisol. We found a positive association between mean fGC concentrations and vigilance behavior, but no relationship with the intensity of behavioral responses to alarm calls. However, in response to alarm call playbacks, individuals administered cortisol took slightly longer to resume foraging than control individuals treated with saline solution. Vigilance behavior, which occurs in the presence and absence of dangerous stimuli, serves to detect and avoid potential dangers, whereas responses to alarm calls serve to avoid immediate predation. Our data show that mean fGC excretion in meerkats was associated with vigilance, as a re-occurring anti-predator behavior over long time periods, and experimentally induced elevations of plasma cortisol affected the response to immediate threats. Together, our results indicate an association between the two types of anti-predator behavior and glucocorticoids, but that the underlying mechanisms may differ. Our study emphasizes the need to consider appropriate measures of adrenal activity specific to different contexts when assessing links between stress physiology and different anti-predator behaviors. PMID:25218254

  1. Can wild common marmosets (Callithrix jacchus) solve the parallel strings task?

    PubMed

    Halsey, L G; Bezerra, B M; Souto, A S

    2006-07-01

    Patterned string tasks are a test of perceptual capacity and the understanding of means-end connections. Primates can solve complex forms of this task in laboratories. However, this may not indicate the level of such cognition that is commonly employed in the wild, where decision-making time is often short and distractions such as predator avoidance and competition between conspecifics are often prevalent. The current study tests whether wild common marmosets (Callithrix jacchus) can successfully complete the simplest form of the patterned string task, parallel strings, while in their natural environment. Although 12 out of 13 marmosets could successfully complete the task, in previous laboratory-based studies on primates, the errors at this task by all primate species tested were consistently lower than in the present study. This is probably explained by the added difficulties imposed by the natural setting of the task in the present study, exemplified by a significant increase in observed vigilance behaviour by subject animals prior to attempts at the task that were unsuccessful. The undertaking of such tasks by common marmosets in situ probably provides a more reasonable representation of the levels of cognitive capacity expressed by this species in the wild than do laboratory-based studies of the task.

  2. Novel analysis of sleep patterns in rats separates periods of vigilance cycling from long-duration wake events.

    PubMed

    Simasko, Steven M; Mukherjee, Sanjib

    2009-01-23

    Rats are polyphasic sleepers. However, a formal definition of when one sleep episode ends and another begins has not been put forth. In the present study we examine the distribution of wake episode durations and based on this distribution conclude there are multiple components of wake. If the wake episode exceeds 300 s the wake episode is assigned to long-duration wake (LDW), if the episode is less than 300 s it is assigned to brief wake (BW). Further support for this separation was found in close analysis of the EEG power spectrum in BW versus LDW. We then used LDW episodes to separate one sleep episode from another. We term the sleep episodes vigilance cycling (VC) because the rat is cycling between the vigilance states of BW, slow-wave sleep (SWS), and rapid-eye movement sleep (REMS). We find that the characteristics of VC are different in the light period versus the dark period. We further find that as VC episodes progress, SWS pressure lessens, but the amount of time spent in REMS increases. These findings suggest that VC episodes are regulated and meaningful to the sleep behavior of rats. The use of the concepts of LDW and VC provides additional insights into the description of sleep patterns in rats that may be important in the development of a complete description of sleep behavior in this animal. PMID:18835301

  3. Chronic Alcohol Treatment in Rats Alters Sleep by Fragmenting Periods of Vigilance Cycling in the Light Period with Extended Wakenings

    PubMed Central

    Mukherjee, Sanjib; Simasko, Steven M.

    2009-01-01

    Studies have shown that disturbed sleep produced by chronic alcohol abuse in humans can predict relapse drinking after periods of abstinence. How alcohol produces disturbed sleep remains unknown. In this study we used a novel analysis of sleep to examine the effects of alcohol on sleep patterns in rats. This analysis separates waking into multiple components and defines a period labeled vigilance cycling (VC) in which the rat rapidly cycles through various vigilance states. These VC episodes are separated by long duration wake periods (LDW). We find that 6 weeks of alcohol (6% in a liquid diet) caused fragmentation of extended VC episodes that normally occur in the light period. However, total daily amounts of slow-wave sleep (SWS) and rapid-eye movement sleep (REMS) remained constant. The daily amount of wake, SWS, and REMS remained constant because the alcohol treated rats increased the amount of VC in the dark period, and the sleep nature of VC in the dark period became more intense. In addition, we observed more wake and less REMS early in the light period in alcohol treated rats. All effects completely reversed by day 16 of alcohol withdrawal. Comparison of the effects of chronic alcohol to acute alcohol exposure demonstrated the effects of chronic alcohol are due to adaptation and not the acute presence of alcohol. The effects of chronic alcohol treatment in rats mimic the effects reported in humans (REMS suppression, difficulty falling asleep, and difficulty remaining asleep). PMID:19014977

  4. Novel Analysis of Sleep Patterns in Rats Separates Periods of Vigilance Cycling from Long Duration Wake Events

    PubMed Central

    Simasko, Steven M.; Mukherjee, Sanjib

    2009-01-01

    Rats are polyphasic sleepers. However, a formal definition of when one sleep episode ends and another begins has not been put forth. In the present study we examine the distribution of wake episode durations and based on this distribution conclude there are multiple components of wake. If the wake episode exceeds 300 sec the wake episode is assigned to long duration wake (LDW), if the episode is less than 300 sec it is assigned to brief wake (BW). Further support for this separation was found in close analysis of the EEG power spectrum in BW versus LDW. We then used LDW episodes to separate one sleep episode from another. We term the sleep episodes vigilance cycling (VC) because the rat is cycling between the vigilance states of brief wake (BW), slow-wave sleep (SWS), and rapid-eye movement sleep (REMS). We find that the characteristics of VC are different in the light period versus the dark period. We further find that as VC episodes progress, SWS pressure lessens, but the amount of time spent in REMS increases. These findings suggest that VC episodes are regulated and meaningful to the sleep behavior of rats. The use of the concepts of LDW and VC provides additional insights into the description of sleep patterns in rats that may be important in the development of a complete description of sleep behavior in this animal. PMID:18835301

  5. Trait rejection sensitivity is associated with vigilance and defensive response rather than detection of social rejection cues

    PubMed Central

    Kawamoto, Taishi; Nittono, Hiroshi; Ura, Mitsuhiro

    2015-01-01

    Prior studies suggest that psychological difficulties arise from higher trait Rejection Sensitivity (RS)—heightened vigilance and differential detection of social rejection cues and defensive response to. On the other hand, from an evolutionary perspective, rapid and efficient detection of social rejection cues can be considered beneficial. We conducted a survey and an electrophysiological experiment to reconcile this seeming contradiction. We compared the effects of RS and Rejection Detection Capability (RDC) on perceived interpersonal experiences (Study 1) and on neurocognitive processes in response to cues of social rejection (disgusted faces; Study 2). We found that RS and RDC were not significantly related, although RS was positively related to perceived social rejection experiences and RDC was positively related to perceived social inclusion experiences. Event-related brain potentials (ERPs) revealed that higher RS was related to cognitive avoidance (i.e., P1) and heightened motivated attention (i.e., late positive potential: LPP), but not to facial expression encoding (i.e., N170) toward disgusted faces. On the other hand, higher RDC was related to heightened N170 amplitude, but not to P1 and LPP amplitudes. These findings imply that sensitivity to rejection is apparently distinct from the ability to detect social rejection cues and instead reflects intense vigilance and defensive response to those cues. We discussed an alternative explanation of the relationship between RS and RDC from a signal detection perspective. PMID:26483750

  6. Functional Task Test (FTT)

    NASA Technical Reports Server (NTRS)

    Bloomberg, Jacob J.; Mulavara, Ajitkumar; Peters, Brian T.; Rescheke, Millard F.; Wood, Scott; Lawrence, Emily; Koffman, Igor; Ploutz-Snyder, Lori; Spiering, Barry A.; Feeback, Daniel L.; Platts, Steven H.; Stenger, Michael B.; Lee, Stuart M.C.; Arzeno, Natalia; Feiveson, Alan H.; Ryder, Jeffrey; Garcia, Yamil; Guilliams, Mark E.

    2009-01-01

    This slide presentation reviews the Functional Task Test (FTT), an interdisciplinary testing regimen that has been developed to evaluate astronaut postflight functional performance and related physiological changes. The objectives of the project are: (1) to develop a set of functional tasks that represent critical mission tasks for the Constellation Program, (2) determine the ability to perform these tasks after space flight, (3) Identify the key physiological factors that contribute to functional decrements and (4) Use this information to develop targeted countermeasures.

  7. Task Time Tracker

    2013-07-24

    This client-side web app tracks the amount of time spent on arbitrary tasks. It allosw the creation of an unlimited number of arbitrarily named tasks ans via simple interactions, tracks the amount of time spent working on the drfined tasks.

  8. Launching Complex Tasks

    ERIC Educational Resources Information Center

    Jackson, Kara J.; Shahan, Emily C.; Gibbons, Lynsey K.; Cobb, Paul A.

    2012-01-01

    Mathematics lessons can take a variety of formats. In this article, the authors discuss lessons organized around complex mathematical tasks. These lessons usually unfold in three phases. First, the task is introduced to students. Second, students work on solving the task. Third, the teacher "orchestrates" a concluding whole-class discussion in…

  9. Relationship between Reaction Time, Fine Motor Control, and Visual-Spatial Perception on Vigilance and Visual-Motor Tasks in 22q11.2 Deletion Syndrome

    ERIC Educational Resources Information Center

    Howley, Sarah A.; Prasad, Sarah E.; Pender, Niall P.; Murphy, Kieran C.

    2012-01-01

    22q11.2 Deletion Syndrome (22q11DS) is a common microdeletion disorder associated with mild to moderate intellectual disability and specific neurocognitive deficits, particularly in visual-motor and attentional abilities. Currently there is evidence that the visual-motor profile of 22q11DS is not entirely mediated by intellectual disability and…

  10. Grid Task Execution

    NASA Technical Reports Server (NTRS)

    Hu, Chaumin

    2007-01-01

    IPG Execution Service is a framework that reliably executes complex jobs on a computational grid, and is part of the IPG service architecture designed to support location-independent computing. The new grid service enables users to describe the platform on which they need a job to run, which allows the service to locate the desired platform, configure it for the required application, and execute the job. After a job is submitted, users can monitor it through periodic notifications, or through queries. Each job consists of a set of tasks that performs actions such as executing applications and managing data. Each task is executed based on a starting condition that is an expression of the states of other tasks. This formulation allows tasks to be executed in parallel, and also allows a user to specify tasks to execute when other tasks succeed, fail, or are canceled. The two core components of the Execution Service are the Task Database, which stores tasks that have been submitted for execution, and the Task Manager, which executes tasks in the proper order, based on the user-specified starting conditions, and avoids overloading local and remote resources while executing tasks.

  11. Melatonin modulates tonic immobility and vigilance behavioural responses of broiler chickens to lighting regimens during the hot-dry season.

    PubMed

    Sinkalu, Victor Olusegun; Ayo, Joseph O; Adelaiye, Alexander B; Hambolu, Joseph O

    2016-10-15

    Experiments were conducted with the aim of determining the influence of melatonin administration on vigilance and tonic immobility (TI) responses of Marshall broiler chickens. The broiler chickens were reared on different lighting regimens and subjected to heat stress during the hot-dry season. Simple random sampling was used to assign 300 broiler chicks into three groups, comprising 100 broiler chicks each. Group I (12D:12L cycle) was raised under natural photoperiod of 12-h light and 12-h darkness, without melatonin supplementation. Group II (CL) was kept under 24-h continuous lighting, without melatonin administration. Group III (CL+MEL) was raised under 24-h continuous lighting; with melatonin supplementation at 0.5mg/kg per os, via drinking water using a syringe. Beginning from day-old, broiler chickens in group III were individually administered with melatonin once daily for 8weeks at 17:00h. TI was induced by manual restraint, and vigilance elicited at self-righting graded for three days, two weeks apart, in 15 labeled broiler chickens from each of the three groups; at 06:00h, 13:00h and 18:00h, starting from week 4-8. Each broiler chicken was laid on its back in a U-shaped cradle, covered with cloth. Thermal microenvironment parameters of dry bulb temperature (DBT) and relative humidity (RH) were recorded at the experimental site, concurrently during the vigilance and TI tests. Inside the broiler chickens' house, the weekly temperature-humidity index (THI) was lowest at week 4 of the study, with the value of 48.60±0.08°C. At week 4, the relationship between the THI and TI induction attempts was stronger in 12D:12L cycle (r=0.589, P<0.001) than CL (r=0.264, P>0.05) or CL+MEL (r=0.096, P>0.05) broiler chickens. This indicated that the broiler chickens on 12D:12L cycle were more active compared to their melatonin-treated counterparts, apparently due to adverse effects of high DBT and high RH on the broiler chickens during the hot-dry season. The highest

  12. The Correlation between Sex, Age, Educational Background, and Hours of Service on Vigilance Level of ATC Officers in Air Nav Surabaya, Indonesia

    ERIC Educational Resources Information Center

    Saleh, Lalu Muhammad; Suwandi, Tjipto; Hamidah

    2016-01-01

    The vigilance of an Air Traffic Control (ATC) officer determines aviation safety. The number of aviation accidents tends to be increasing in recent years. Aviation accidents may be caused by human errors (i.e. errors made by pilot or ATC officer) or unsafe work condition. Sex, age, educational background, and hours of service might affect…

  13. Automatic vigilance: the attention-grabbing power of approach- and avoidance-related social information.

    PubMed

    Wentura, D; Rothermund, K; Bak, P

    2000-06-01

    The automatic processing of information was investigated, varying valence (positive vs. negative) and relevance (other-relevant traits [ORT] vs. possessor-relevant traits [PRT]; G. Peeters, 1983) of stimuli. ORTs denote unconditionally positive or negative consequences for persons in the social environment of the holder of the trait (e.g., honest, brutal) whereas PRTs denote unconditionally positive or negative consequences for the trait holder (e.g., happy, depressive). In 2 experiments using the Stroop paradigm, larger interference effects were found for ORTs than PRTs. This is due to the behavior-relatedness of ORTs. In a go/no-go lexical decision task (Experiment 3), participants either had to withdraw their finger from a pressed key (i.e., "avoid") or had to press a key (i.e., "approach") if a word was presented. Responses to negative ORTs were relatively faster in the withdraw condition, whereas positive ORTs were relatively faster in the press condition. PMID:10870906

  14. TNFα G308A polymorphism is associated with resilience to sleep deprivation-induced psychomotor vigilance performance impairment in healthy young adults.

    PubMed

    Satterfield, Brieann C; Wisor, Jonathan P; Field, Stephanie A; Schmidt, Michelle A; Van Dongen, Hans P A

    2015-07-01

    Cytokines such as TNFα play an integral role in sleep/wake regulation and have recently been hypothesized to be involved in cognitive impairment due to sleep deprivation. We examined the effect of a guanine to adenine substitution at position 308 in the TNFα gene (TNFα G308A) on psychomotor vigilance performance impairment during total sleep deprivation. A total of 88 healthy women and men (ages 22-40) participated in one of five laboratory total sleep deprivation experiments. Performance on a psychomotor vigilance test (PVT) was measured every 2-3h. The TNFα 308A allele, which is less common than the 308G allele, was associated with greater resilience to psychomotor vigilance performance impairment during total sleep deprivation (regardless of time of day), and also provided a small performance benefit at baseline. The effect of genotype on resilience persisted when controlling for between-subjects differences in age, gender, race/ethnicity, and baseline sleep duration. The TNFα G308A polymorphism predicted less than 10% of the overall between-subjects variance in performance impairment during sleep deprivation. Nonetheless, the differential effect of the polymorphism at the peak of performance impairment was more than 50% of median performance impairment at that time, which is sizeable compared to the effects of other genotypes reported in the literature. Our findings provided evidence for a role of TNFα in the effects of sleep deprivation on psychomotor vigilance performance. Furthermore, the TNFα G308A polymorphism may have predictive potential in a biomarker panel for the assessment of resilience to psychomotor vigilance performance impairment due to sleep deprivation.

  15. TNFα G308A polymorphism is associated with resilience to sleep deprivation-induced psychomotor vigilance performance impairment in healthy young adults

    PubMed Central

    Satterfield, Brieann C.; Wisor, Jonathan P.; Field, Stephanie A.; Schmidt, Michelle A.; Van Dongen, Hans P.A.

    2015-01-01

    Cytokines such as TNFα play an integral role in sleep/wake regulation and have recently been hypothesized to be involved in cognitive impairment due to sleep deprivation. We examined the effect of a guanine to adenine substitution at position 308 in the TNFα gene (TNFα G308A) on psychomotor vigilance performance impairment during total sleep deprivation. A total of 88 healthy women and men (ages 22–40) participated in one of five laboratory total sleep deprivation experiments. Performance on a psychomotor vigilance test (PVT) was measured every 2 to 3 h. The TNFα 308A allele, which is less common than the 308G allele, was associated with greater resilience to psychomotor vigilance performance impairment during total sleep deprivation (regardless of time of day), and also provided a small performance benefit at baseline. The effect of genotype on resilience persisted when controlling for between-subjects differences in age, gender, race/ethnicity, and baseline sleep duration. The TNFα G308A polymorphism predicted less than 10% of the overall between-subjects variance in performance impairment during sleep deprivation. Nonetheless, the differential effect of the polymorphism at the peak of performance impairment was more than 50% of median performance impairment at that time, which is sizeable compared to the effects of other genotypes reported in the literature. Our findings provided evidence for a role of TNFα in the effects of sleep deprivation on psychomotor vigilance performance. Furthermore, the TNFα G308A polymorphism may have predictive potential in a biomarker panel for the assessment of resilience to psychomotor vigilance performance impairment due to sleep deprivation. PMID:25542735

  16. NSI security task: Overview

    NASA Technical Reports Server (NTRS)

    Tencati, Ron

    1991-01-01

    An overview is presented of the NASA Science Internet (NSI) security task. The task includes the following: policies and security documentation; risk analysis and management; computer emergency response team; incident handling; toolkit development; user consulting; and working groups, conferences, and committees.

  17. Task Description Language

    NASA Technical Reports Server (NTRS)

    Simmons, Reid; Apfelbaum, David

    2005-01-01

    Task Description Language (TDL) is an extension of the C++ programming language that enables programmers to quickly and easily write complex, concurrent computer programs for controlling real-time autonomous systems, including robots and spacecraft. TDL is based on earlier work (circa 1984 through 1989) on the Task Control Architecture (TCA). TDL provides syntactic support for hierarchical task-level control functions, including task decomposition, synchronization, execution monitoring, and exception handling. A Java-language-based compiler transforms TDL programs into pure C++ code that includes calls to a platform-independent task-control-management (TCM) library. TDL has been used to control and coordinate multiple heterogeneous robots in projects sponsored by NASA and the Defense Advanced Research Projects Agency (DARPA). It has also been used in Brazil to control an autonomous airship and in Canada to control a robotic manipulator.

  18. [Evoked potentials and vigilance states induced during the course of choice reaction time tests].

    PubMed

    Banquet, J P; Bourzeix, J C; Lesèvre, N

    1979-01-01

    Characteristics of Visual Evoked Potentials (N120, P200, P300) were investigated during choice reaction time situations in a group of 10 subjects practising meditation (E.S.) versus a matched control group (C.S.) During a series of visual stimuli occuring at fixed intervals, with 10% random omissions, the subjects were asked : 1) to respond by a finger displacement to each visual stimulus; 2) to hold on the response to the stimulus and to respond to omission. Both tasks were recorded before and after the practice of meditation or rest for the controls. The intergroup comparison showed that the experimental subjects had faster RT's with less mistakes, and N120 and P200 of larger amplitude and shorter latency. These differencies were significant before and after meditation. The transient effects of meditation or rest, were opposite for the two groups : whereas after meditation the RT's became longer with less mistakes, and the amplitude of P300 larger, after rest there was a decrease of the P300 amplitude and no change in the RT's of the controls. These results are interpreted in terms of selective attention capacity and information processing strategies, A.S.C. being used as a model for the study of these processes.

  19. Spontaneous eyelid closures link vigilance fluctuation with fMRI dynamic connectivity states

    PubMed Central

    Wang, Chenhao; Ong, Ju Lynn; Patanaik, Amiya; Chee, Michael W. L.

    2016-01-01

    Fluctuations in resting-state functional connectivity occur but their behavioral significance remains unclear, largely because correlating behavioral state with dynamic functional connectivity states (DCS) engages probes that disrupt the very behavioral state we seek to observe. Observing spontaneous eyelid closures following sleep deprivation permits nonintrusive arousal monitoring. During periods of low arousal dominated by eyelid closures, sliding-window correlation analysis uncovered a DCS associated with reduced within-network functional connectivity of default mode and dorsal/ventral attention networks, as well as reduced anticorrelation between these networks. Conversely, during periods when participants’ eyelids were wide open, a second DCS was associated with less decoupling between the visual network and higher-order cognitive networks that included dorsal/ventral attention and default mode networks. In subcortical structures, eyelid closures were associated with increased connectivity between the striatum and thalamus with the ventral attention network, and greater anticorrelation with the dorsal attention network. When applied to task-based fMRI data, these two DCS predicted interindividual differences in frequency of behavioral lapsing and intraindividual temporal fluctuations in response speed. These findings with participants who underwent a night of total sleep deprivation were replicated in an independent dataset involving partially sleep-deprived participants. Fluctuations in functional connectivity thus appear to be clearly associated with changes in arousal. PMID:27512040

  20. Spontaneous eyelid closures link vigilance fluctuation with fMRI dynamic connectivity states.

    PubMed

    Wang, Chenhao; Ong, Ju Lynn; Patanaik, Amiya; Zhou, Juan; Chee, Michael W L

    2016-08-23

    Fluctuations in resting-state functional connectivity occur but their behavioral significance remains unclear, largely because correlating behavioral state with dynamic functional connectivity states (DCS) engages probes that disrupt the very behavioral state we seek to observe. Observing spontaneous eyelid closures following sleep deprivation permits nonintrusive arousal monitoring. During periods of low arousal dominated by eyelid closures, sliding-window correlation analysis uncovered a DCS associated with reduced within-network functional connectivity of default mode and dorsal/ventral attention networks, as well as reduced anticorrelation between these networks. Conversely, during periods when participants' eyelids were wide open, a second DCS was associated with less decoupling between the visual network and higher-order cognitive networks that included dorsal/ventral attention and default mode networks. In subcortical structures, eyelid closures were associated with increased connectivity between the striatum and thalamus with the ventral attention network, and greater anticorrelation with the dorsal attention network. When applied to task-based fMRI data, these two DCS predicted interindividual differences in frequency of behavioral lapsing and intraindividual temporal fluctuations in response speed. These findings with participants who underwent a night of total sleep deprivation were replicated in an independent dataset involving partially sleep-deprived participants. Fluctuations in functional connectivity thus appear to be clearly associated with changes in arousal. PMID:27512040

  1. Introducing uninteresting tasks to children: a comparison of the effects of rewards and autonomy support.

    PubMed

    Joussemet, Mireille; Koestner, Richard; Lekes, Natasha; Houlfort, Nathalie

    2004-02-01

    Two experiments compared rewards and autonomy support as methods to promote children's self-regulation for an uninteresting vigilance task. Dependent measures were ratings of positive affect, perception of the task's value, and free-choice engagement. ANOVA results revealed some positive effects associated with autonomy support, whereas no effect for rewards was found in either study. The outcomes of most interest were correlations between free-choice behavior and self-reported measures of affect and value, reflecting the level of integration in self-regulation. As predicted by self-determination theory (Deci & Ryan, 1985, 1991, 2000), rewards were associated with behaviors incongruent from affect and value, whereas autonomy support led to integrated self-regulation. This finding was first detected in Study 1 and later replicated in Study 2. Together, these results point to autonomy support as a beneficial alternative to the common use of rewards.

  2. Can providing feedback on driving behavior and training on parental vigilant care affect male teen drivers and their parents?

    PubMed

    Farah, Haneen; Musicant, Oren; Shimshoni, Yaara; Toledo, Tomer; Grimberg, Einat; Omer, Haim; Lotan, Tsippy

    2014-08-01

    This study focuses on investigating the driving behavior of young novice male drivers during the first year of driving (three months of accompanied driving and the following nine months of solo driving). The study's objective is to examine the potential of various feedback forms on driving to affect young drivers' behavior and to mitigate the transition from accompanied to solo driving. The study examines also the utility of providing parents with guidance on how to exercise vigilant care regarding their teens' driving. Driving behavior was evaluated using data collected by In-Vehicle Data Recorders (IVDR), which document events of extreme g-forces measured in the vehicles. IVDR systems were installed in 242 cars of the families of young male drivers, however, only 217 families of young drivers aged 17-22 (M=17.5; SD=0.8) completed the one year period. The families were randomly allocated into 4 groups: (1) Family feedback: In which all the members of the family were exposed to feedback on their own driving and on that of the other family members; (2) Parental training: in which in addition to the family feedback, parents received personal guidance on ways to enhance vigilant care regarding their sons' driving; (3) Individual feedback: In which family members received feedback only on their own driving behavior (and were not exposed to the data on other family members); (4) CONTROL: Group that received no feedback at all. The feedback was provided to the different groups starting from the solo period, thus, the feedback was not provided during the supervised period. The data collected by the IVDRs was first analyzed using analysis of variance in order to compare the groups with respect to their monthly event rates. Events' rates are defined as the number of events in a trip divided by its duration. This was followed by the development and estimation of random effect negative binomial models that explain the monthly event rates of young drivers and their parents

  3. Text-speak processing and the sustained attention to response task.

    PubMed

    Head, James; Russell, Paul N; Dorahy, Martin J; Neumann, Ewald; Helton, William S

    2012-01-01

    We examined performance in a sustained attention to response task (SART) (Experiment 1) and a more traditionally formatted vigilance task (Experiment 2) using novel word stimuli (text-speak) and normally spelt words. This enabled us to address whether the SART is a better measure of sustained attention or of response strategy, and to investigate the cognitive demands of text-speak processing. In Experiment 1, 72 participants completed a subset (text-speak) and a word SART, as well as a self-reported text experience questionnaire. Those who reported more proficiency and experience with text-speak made more errors on the subset SART, but this appeared to be due to their increase in response speed. This did not occur in the word SART. In Experiment 2, 14 participants completed high No-Go, low-Go (more traditional response format) versions of these tasks to further investigate the cognitive demands of text-speak processing. Response latency increased over periods of watch only for the text-speak task, not for the word task. The results of Experiment 1 support the perspective that the SART is highly sensitive to response strategy, and the results of both experiments together indicate target detection tasks may be a novel way of investigating the cognitive demands of text-speak processing.

  4. Efficient mental workload estimation using task-independent EEG features

    NASA Astrophysics Data System (ADS)

    Roy, R. N.; Charbonnier, S.; Campagne, A.; Bonnet, S.

    2016-04-01

    Objective. Mental workload is frequently estimated by EEG-based mental state monitoring systems. Usually, these systems use spectral markers and event-related potentials (ERPs). To our knowledge, no study has directly compared their performance for mental workload assessment, nor evaluated the stability in time of these markers and of the performance of the associated mental workload estimators. This study proposes a comparison of two processing chains, one based on the power in five frequency bands, and one based on ERPs, both including a spatial filtering step (respectively CSP and CCA), an FLDA classification and a 10-fold cross-validation. Approach. To get closer to a real life implementation, spectral markers were extracted from a short window (i.e. towards reactive systems) that did not include any motor activity and the analyzed ERPs were elicited by a task-independent probe that required a reflex-like answer (i.e. close to the ones required by dead man’s vigilance devices). The data were acquired from 20 participants who performed a Sternberg memory task for 90 min (i.e. 2/6 digits to memorize) inside which a simple detection task was inserted. The results were compared both when the testing was performed at the beginning and end of the session. Main results. Both chains performed significantly better than random; however the one based on the spectral markers had a low performance (60%) and was not stable in time. Conversely, the ERP-based chain gave very high results (91%) and was stable in time. Significance. This study demonstrates that an efficient and stable in time workload estimation can be achieved using task-independent spatially filtered ERPs elicited in a minimally intrusive manner.

  5. Melatonin modulates tonic immobility and vigilance behavioural responses of broiler chickens to lighting regimens during the hot-dry season.

    PubMed

    Sinkalu, Victor Olusegun; Ayo, Joseph O; Adelaiye, Alexander B; Hambolu, Joseph O

    2016-10-15

    Experiments were conducted with the aim of determining the influence of melatonin administration on vigilance and tonic immobility (TI) responses of Marshall broiler chickens. The broiler chickens were reared on different lighting regimens and subjected to heat stress during the hot-dry season. Simple random sampling was used to assign 300 broiler chicks into three groups, comprising 100 broiler chicks each. Group I (12D:12L cycle) was raised under natural photoperiod of 12-h light and 12-h darkness, without melatonin supplementation. Group II (CL) was kept under 24-h continuous lighting, without melatonin administration. Group III (CL+MEL) was raised under 24-h continuous lighting; with melatonin supplementation at 0.5mg/kg per os, via drinking water using a syringe. Beginning from day-old, broiler chickens in group III were individually administered with melatonin once daily for 8weeks at 17:00h. TI was induced by manual restraint, and vigilance elicited at self-righting graded for three days, two weeks apart, in 15 labeled broiler chickens from each of the three groups; at 06:00h, 13:00h and 18:00h, starting from week 4-8. Each broiler chicken was laid on its back in a U-shaped cradle, covered with cloth. Thermal microenvironment parameters of dry bulb temperature (DBT) and relative humidity (RH) were recorded at the experimental site, concurrently during the vigilance and TI tests. Inside the broiler chickens' house, the weekly temperature-humidity index (THI) was lowest at week 4 of the study, with the value of 48.60±0.08°C. At week 4, the relationship between the THI and TI induction attempts was stronger in 12D:12L cycle (r=0.589, P<0.001) than CL (r=0.264, P>0.05) or CL+MEL (r=0.096, P>0.05) broiler chickens. This indicated that the broiler chickens on 12D:12L cycle were more active compared to their melatonin-treated counterparts, apparently due to adverse effects of high DBT and high RH on the broiler chickens during the hot-dry season. The highest

  6. Impact of overnight traffic noise on sleep quality, sleepiness, and vigilant attention in long-haul truck drivers: Results of a pilot study.

    PubMed

    Popp, Roland Fj; Maier, Stefanie; Rothe, Siegfried; Zulley, Jürgen; Crönlein, Tatjana; Wetter, Thomas C; Rupprecht, Rainer; Hajak, Göran

    2015-01-01

    This study aimed to evaluate the impact of traffic noise along the motorway on sleep quality, sleepiness, and vigilant attention in long-haul truck drivers. This was a randomized, crossover, within-subject controlled study. Healthy long-haul truck drivers spent 6 consecutive nights in a real truck berth with full sleep laboratory equipment. During 3 nights, subjects were exposed to replayed traffic noise alongside motorways, whereas the other 3 nights were without traffic noise. Polysomnography was recorded during the nights and numerous sleepiness tests and vigilance examinations were performed during the following standardized working day. Outcome measures were compared between noisy and silent nights using the paired Wilcoxon test. Ten healthy long-haul truck drivers with a mean age of 36.3 ± 7.3 years completed the study as planned. On noisy nights, subjects had greater latencies to the rapid eye movement (REM) phase (90 ± 32 min vs 69 ± 16 min, P = 0.074) and higher percentages of sleep stage 1 (13.7 ± 5.5% vs 11.2 ± 4.4%; P = 0.059). Subjects also rated their sleep quality as having been better during nights without noise (28.1 ± 3.7 vs 30.3 ± 6.2, P = 0.092). The impact of these differences on daytime sleepiness and vigilance was rather low; however, mean Karolinska Sleepiness Scale (KSS) scores measured during the course of the following day were higher on six out of eight occasions after noisy nights. The effects of overnight traffic noise on sleep quality are detectable but unlikely to have any major impact on the vigilant attention and driving performance of long haul-truck drivers with low nocturnal noise sensitivity. This might not be true for subgroups prone to sleeping disorders.

  7. Impact of overnight traffic noise on sleep quality, sleepiness, and vigilant attention in long-haul truck drivers: Results of a pilot study

    PubMed Central

    Popp, Roland FJ; Maier, Stefanie; Rothe, Siegfried; Zulley, Jürgen; Crönlein, Tatjana; Wetter, Thomas C; Rupprecht, Rainer; Hajak, Göran

    2015-01-01

    This study aimed to evaluate the impact of traffic noise along the motorway on sleep quality, sleepiness, and vigilant attention in long-haul truck drivers. This was a randomized, crossover, within-subject controlled study. Healthy long-haul truck drivers spent 6 consecutive nights in a real truck berth with full sleep laboratory equipment. During 3 nights, subjects were exposed to replayed traffic noise alongside motorways, whereas the other 3 nights were without traffic noise. Polysomnography was recorded during the nights and numerous sleepiness tests and vigilance examinations were performed during the following standardized working day. Outcome measures were compared between noisy and silent nights using the paired Wilcoxon test. Ten healthy long-haul truck drivers with a mean age of 36.3 ± 7.3 years completed the study as planned. On noisy nights, subjects had greater latencies to the rapid eye movement (REM) phase (90 ± 32 min vs 69 ± 16 min, P = 0.074) and higher percentages of sleep stage 1 (13.7 ± 5.5% vs 11.2 ± 4.4%; P = 0.059). Subjects also rated their sleep quality as having been better during nights without noise (28.1 ± 3.7 vs 30.3 ± 6.2, P = 0.092). The impact of these differences on daytime sleepiness and vigilance was rather low; however, mean Karolinska Sleepiness Scale (KSS) scores measured during the course of the following day were higher on six out of eight occasions after noisy nights. The effects of overnight traffic noise on sleep quality are detectable but unlikely to have any major impact on the vigilant attention and driving performance of long haul-truck drivers with low nocturnal noise sensitivity. This might not be true for subgroups prone to sleeping disorders. PMID:26572698

  8. "Every shut eye, ain't sleep": The role of racism-related vigilance in racial/ethnic disparities in sleep difficulty.

    PubMed

    Hicken, Margaret T; Lee, Hedwig; Ailshire, Jennifer; Burgard, Sarah A; Williams, David R

    2013-06-01

    Although racial/ethnic disparities in health have been well-characterized in biomedical, public health, and social science research, the determinants of these disparities are still not well-understood. Chronic psychosocial stress related specifically to the American experience of institutional and interpersonal racial discrimination may be an important determinant of these disparities, as a growing literature in separate scientific disciplines documents the adverse health effects of stress and the greater levels of stress experienced by non-White compared to White Americans. However, the empirical literature on the importance of stress for health and health disparities specifically due to racial discrimination, using population-representative data, is still small and mixed. In this paper, we explore the association between a novel measure of racially-salient chronic stress - "racism-related vigilance" - and sleep difficulty. We found that, compared to the White adults in our sample, Black (but not Hispanic) adults reported greater levels of vigilance. This vigilance was positively associated with sleep difficulty to similar degrees for all racial/ethnic groups in our sample (White, Black, Hispanic). Black adults reported greater levels of sleep difficulty compared to White adults. This disparity was slightly attenuated after adjustment for education and income. However, this disparity was completely attenuated after adjustment for racism-related vigilance. We found similar patterns of results for Hispanic compared to White adults, however, the disparities in sleep difficulty were smaller and not statistically significant. Because of the importance of sleep quality to health, our results suggest that the anticipation of and perseveration about racial discrimination is an important determinant of racial disparities in health.

  9. Involved-vigilant parenting and socio-emotional well-being among black youth: the moderating influence of natural mentoring relationships.

    PubMed

    Hurd, Noelle M; Varner, Fatima A; Rowley, Stephanie J

    2013-10-01

    Positive relationships with parents and nonparental adults have the potential to bolster Black adolescents' socio-emotional well-being. Though each type of intergenerational relationship has been linked to more positive youth outcomes, few studies have examined the interactive influences of parenting and natural mentoring relationships on the socio-emotional development of Black youth. In the current study, we examined associations between involved-vigilant parenting and the psychological well-being and social skills of Black early adolescents (n = 259; 58 % female; mean age = 13.56, SD = .96) across types of natural mentoring relationships. Using K-means cluster analysis, we identified two types of mentoring relationships (less connected and more connected) based on relationship length, involvement, closeness, and frequency of contact. Youth with more connected mentoring relationships (n = 123) had higher psychological well-being and social skills than youth with no mentor (n = 64) or less connected mentors (n = 72). Youth without a natural mentor and youth with less connected mentors did not differ in their levels of social skills or psychological well-being. Structural equation modeling was conducted to determine if associations between involved-vigilant parenting and youths' psychological well-being and social skills varied among youth with a more connected mentoring relationship in comparison to youth without a mentor or with a less connected mentor, controlling for participants' gender, age, school, and parental education. The positive associations between involved-vigilant parenting and adolescents' psychological well-being and social skills were weaker among adolescents with a more connected mentoring relationship in comparison to their peers without or with a less connected mentoring relationship. These results suggest that youth may be more strongly influenced by involved-vigilant parenting in the absence of a strongly connected natural mentoring

  10. Task Switching in a Hierarchical Task Structure: Evidence for the Fragility of the Task Repetition Benefit

    ERIC Educational Resources Information Center

    Lien, Mei-Ching; Ruthruff, Eric

    2004-01-01

    This study examined how task switching is affected by hierarchical task organization. Traditional task-switching studies, which use a constant temporal and spatial distance between each task element (defined as a stimulus requiring a response), promote a flat task structure. Using this approach, Experiment 1 revealed a large switch cost of 238 ms.…

  11. Task-specific Dystonias

    PubMed Central

    Torres-Russotto, Diego; Perlmutter, Joel S.

    2009-01-01

    Task-specific dystonias are primary focal dystonias characterized by excessive muscle contractions producing abnormal postures during selective motor activities that often involve highly skilled, repetitive movements. Historically these peculiar postures were considered psychogenic but have now been classified as forms of dystonia. Writer’s cramp is the most commonly identified task-specific dystonia and has features typical of this group of disorders. Symptoms may begin with lack of dexterity during performance of a specific motor task with increasingly abnormal posturing of the involved body part as motor activity continues. Initially, the dystonia may manifest only during the performance of the inciting task, but as the condition progresses it may also occur during other activities or even at rest. Neurological exam is usually unremarkable except for the dystonia-related abnormalities. Although the precise pathophysiology remains unclear, increasing evidence suggests reduced inhibition at different levels of the sensorimotor system. Symptomatic treatment options include oral medications, botulinum toxin injections, neurosurgical procedures, and adaptive strategies. Prognosis may vary depending upon body part involved and specific type of task affected. Further research may reveal new insights into the etiology, pathophysiology, natural history, and improved treatment of these conditions. PMID:18990127

  12. Brief report: manipulation of task difficulty in inhibitory control tasks.

    PubMed

    Lindqvist, Sofia; Thorell, Lisa B

    2009-01-01

    The present study investigated how task difficulty can be manipulated in inhibitory control tasks. Tasks from three widely used task paradigms - a Go/No-Go task, a Stop-Signal task,and a Flanker task - were manipulated on two parameters each (Go/No-Go task: interstimulus interval, prepotency. Stop-signal task: stop-signal-delay, prepotency. Flanker task:number of distractors, size of target stimulus). Participants were 86 children (age 4-6) from a population-based sample. The results showed no significant effects on the Go/No-Go task but both main and interaction effects on the Stop-Signal task and the Flanker task. Together, these findings indicate that task difficulty can be successfully manipulated in inhibitory control tasks. However, the interactive rather than additive effects on performance suggest that the level of one parameter only has the desired effect under certain conditions. This new information about how to manipulate task difficulty is important when adapting tasks for use with children of different ages, as well as when designing training programs for improving inhibitory control among children with ADHD. PMID:18608218

  13. Task-Based Learning: The Interaction between Tasks and Learners.

    ERIC Educational Resources Information Center

    Murphy, Jacky

    2003-01-01

    Investigates the relationship between tasks and learners in task-based learning. Findings suggest that manipulation of task characteristics and conditions may not achieve the intended pedagogic outcomes, and that new ways are needed to focus learners' attention of form without sacrificing the meaning-driven principles of task-based learning.…

  14. Embodied Task Dynamics

    ERIC Educational Resources Information Center

    Simko, Juraj; Cummins, Fred

    2010-01-01

    Movement science faces the challenge of reconciling parallel sequences of discrete behavioral goals with observed fluid, context-sensitive motion. This challenge arises with a vengeance in the speech domain, in which gestural primitives play the role of discrete goals. The task dynamic framework has proved effective in modeling the manner in which…

  15. Biomedical applications engineering tasks

    NASA Technical Reports Server (NTRS)

    Laenger, C. J., Sr.

    1976-01-01

    The engineering tasks performed in response to needs articulated by clinicians are described. Initial contacts were made with these clinician-technology requestors by the Southwest Research Institute NASA Biomedical Applications Team. The basic purpose of the program was to effectively transfer aerospace technology into functional hardware to solve real biomedical problems.

  16. Creating Positive Task Constraints

    ERIC Educational Resources Information Center

    Mally, Kristi K.

    2006-01-01

    Constraints are characteristics of the individual, the task, or the environment that mold and shape movement choices and performances. Constraints can be positive--encouraging proficient movements or negative--discouraging movement or promoting ineffective movements. Physical educators must analyze, evaluate, and determine the effect various…

  17. Chizu Task Mapping Tool

    SciTech Connect

    2014-07-01

    Chizu is a tool for Mapping MPI processes or tasks to physical processors or nodes for optimizing communication performance. It takes the communication graph of a High Performance Computing (HPC) application and the interconnection topology of a supercomputer as input. It outputs a new MPI rand to processor mapping, which can be used when launching the HPC application.

  18. Randomization in robot tasks

    NASA Technical Reports Server (NTRS)

    Erdmann, Michael

    1992-01-01

    This paper investigates the role of randomization in the solution of robot manipulation tasks. One example of randomization is shown by the strategy of shaking a bin holding a part in order to orient the part in a desired stable state with some high probability. Randomization can be useful for mobile robot navigation and as a means of guiding the design process.

  19. Project Echo Task Group

    NASA Technical Reports Server (NTRS)

    1964-01-01

    'A technician assigned to the Project Echo Task Group separates the two hemispheres of the Echo 1 container for inspection. The charge that freed the balloon was placed inside of a ring encircling the canister at its equator.' Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, NASA SP-4308, p. 181.

  20. Job Task Analysis.

    ERIC Educational Resources Information Center

    Clemson Univ., SC.

    This publication consists of job task analyses for jobs in textile manufacturing. Information provided for each job in the greige and finishing plants includes job title, job purpose, and job duties with related educational objectives, curriculum, assessment, and outcome. These job titles are included: yarn manufacturing head overhauler, yarn…

  1. Data Center Tasking.

    ERIC Educational Resources Information Center

    Temares, M. Lewis; Lutheran, Joseph A.

    Operations tasking for data center management is discussed. The original and revised organizational structures of the data center at the University of Miami are also described. The organizational strategy addresses the functions that should be performed by the data center, anticipates the specialized skills required, and addresses personnel…

  2. Planetary image conversion task

    NASA Technical Reports Server (NTRS)

    Martin, M. D.; Stanley, C. L.; Laughlin, G.

    1985-01-01

    The Planetary Image Conversion Task group processed 12,500 magnetic tapes containing raw imaging data from JPL planetary missions and produced an image data base in consistent format on 1200 fully packed 6250-bpi tapes. The output tapes will remain at JPL. A copy of the entire tape set was delivered to US Geological Survey, Flagstaff, Ariz. A secondary task converted computer datalogs, which had been stored in project specific MARK IV File Management System data types and structures, to flat-file, text format that is processable on any modern computer system. The conversion processing took place at JPL's Image Processing Laboratory on an IBM 370-158 with existing software modified slightly to meet the needs of the conversion task. More than 99% of the original digital image data was successfully recovered by the conversion task. However, processing data tapes recorded before 1975 was destructive. This discovery is of critical importance to facilities responsible for maintaining digital archives since normal periodic random sampling techniques would be unlikely to detect this phenomenon, and entire data sets could be wiped out in the act of generating seemingly positive sampling results. Reccomended follow-on activities are also included.

  3. Task 1 quarternary tectonics

    SciTech Connect

    Bell, J.W.

    1994-12-31

    Activities on the task of quarternary tectonics for the Yucca Mountain Site investigations are described. Technical topics include: A preliminary reveiw of Bare Mountain Trench; A preliminary detailed lineament map of the Southwestern part of the proposed repository; A discussion on the 1994 Double Spring Flat, Nevada earthquake; and evidence for temporal clustering.

  4. An Adaptive-Duration Version of the PVT Accurately Tracks Changes in Psychomotor Vigilance Induced by Sleep Restriction

    PubMed Central

    Basner, Mathias; Dinges, David F.

    2012-01-01

    Study Objectives: The Psychomotor Vigilance Test (PVT) is a widely used assay of behavioral alertness sensitive to the effects of sleep loss and circadian misalignment. The standard 10-minute duration of the PVT is often considered impractical for operational or clinical environments. Therefore, we developed and validated an adaptive-duration version of the PVT (PVT-A) that stops sampling once it has gathered enough information to correctly classify PVT performance. Design: Repeated-measures experiments involving 10-minute PVT assessments every 2 hours across both acute total sleep deprivation (TSD) and 5 days of chronic partial sleep deprivation (PSD). Setting: Controlled laboratory environment. Participants: Seventy-four healthy subjects (34 women), aged 22 to 45 years. Interventions: A TSD experiment involving 33 hours awake (n = 31 subjects), and a PSD experiment involving 5 nights of 4 hours time in bed (n = 43 subjects). Measurements and Results: The PVT-A algorithm was trained with 527 TSD test bouts and validated with 880 PSD test bouts. Based on our primary outcome measure “number of lapses (response times ≥ 500 ms) plus false starts (premature responses or response times < 100 ms),” 10-minute PVT performance was classified into high (≤ 5 lapses and false starts), medium (> 5 and ≤ 16 lapses and false starts), or low (> 16 lapses and false starts). The decision threshold for PVT-A termination was set so that at least 95% of training data-set tests were classified correctly and no test was classified incorrectly across 2 performance categories (i.e., high as low or low as high), resulting in an average test duration of 6.0 minutes (SD 2.4 min). In the validation data set, 95.7% of test bouts were correctly classified, and there were no incorrect classifications across 2 categories. Agreement corrected for chance was excellent (κ = 0.92). Across the 3 performance categories, sensitivity averaged 93.7% (range 87.2%-100%), and specificity averaged

  5. Novel Rat Model of Weight Drop-Induced Closed Diffuse Traumatic Brain Injury Compatible with Electrophysiological Recordings of Vigilance States.

    PubMed

    Büchele, Fabian; Morawska, Marta M; Schreglmann, Sebastian R; Penner, Marco; Muser, Markus; Baumann, Christian R; Noain, Daniela

    2016-07-01

    Traumatic brain injury (TBI) is a major cause of persistent disabilities such as sleep-wake disorders (SWD). Rodent studies of SWD after TBI are scarce, however, because of lack of appropriate TBI models reproducing acceleration-deceleration forces and compatible with electroencephalography/myography (EEG/EMG)-based recordings of vigilance states. We therefore adapted the Marmarou impact acceleration model to allow for compatibility with EEG-headset implantation. After implantation of EEG/EMG electrodes, we induced closed TBI by a frontal, angular hit with a weight-drop device (56 rats, weight 2500 g, fall height 25 cm). Subsequently, we tested our model's usefulness for long-term studies on a behavioral, electrophysiological, and histological level. Neurological, motor, and memory deficits were assessed with the neurological severity score, open field, and novel object recognition tests, respectively. EEG/EMG recordings were performed in both Sham (n = 7) and TBI (n = 7) rats before and 1, 7, and 28 days after trauma to evaluate sleep-wake proportions and post-traumatic implant stability. Histological assessments included hematoxylin and eosin staining for parenchymal damage and hemorrhage and amyloid precursor protein staining for diffuse axonal damage. All rats survived TBI without major neurological or motor deficits. Memory function was impaired after TBI at weeks 1, 2, and 3 and recovered at week 4. EEG implants were stable for at least 1 month and enabled qualitative and quantitative sleep analyses. Histological assessments revealed no major bleedings or necrosis but intense diffuse axonal damage after TBI. This approach fulfills major pre-conditions for experimental TBI models and offers a possibility to electrophysiologically study behavioral states before and after trauma.

  6. Task Engagement, Cerebral Blood Flow Velocity, and Diagnostic Monitoring for Sustained Attention

    ERIC Educational Resources Information Center

    Matthews, Gerald; Warm, Joel S.; Reinerman-Jones, Lauren E.; Langheim, Lisa K.; Washburn, David A.; Tripp, Lloyd

    2010-01-01

    Loss of vigilance may lead to impaired performance in various applied settings including military operations, transportation, and industrial inspection. Individuals differ considerably in sustained attention, but individual differences in vigilance have proven to be hard to predict. The dependence of vigilance on workload factors is consistent…

  7. Microprocessor multi-task monitor

    SciTech Connect

    Ludemann, C.A.

    1983-01-01

    This paper describes a multi-task monitor program for microprocessors. Although written for the Intel 8085, it incorporates features that would be beneficial for implementation in other microprocessors used in controlling and monitoring experiments and accelerators. The monitor places permanent programs (tasks) arbitrarily located throughout ROM in a priority ordered queue. The programmer is provided with the flexibility to add new tasks or modified versions of existing tasks, without having to comply with previously defined task boundaries or having to reprogram all of ROM. Scheduling of tasks is triggered by timers, outside stimuli (interrupts), or inter-task communications. Context switching time is of the order of tenths of a milllisecond.

  8. Investigation of the effect of EEG-BCI on the simultaneous execution of flight simulation and attentional tasks.

    PubMed

    Vecchiato, Giovanni; Borghini, Gianluca; Aricò, Pietro; Graziani, Ilenia; Maglione, Anton Giulio; Cherubino, Patrizia; Babiloni, Fabio

    2016-10-01

    Brain-computer interfaces (BCIs) are widely used for clinical applications and exploited to design robotic and interactive systems for healthy people. We provide evidence to control a sensorimotor electroencephalographic (EEG) BCI system while piloting a flight simulator and attending a double attentional task simultaneously. Ten healthy subjects were trained to learn how to manage a flight simulator, use the BCI system, and answer to the attentional tasks independently. Afterward, the EEG activity was collected during a first flight where subjects were required to concurrently use the BCI, and a second flight where they were required to simultaneously use the BCI and answer to the attentional tasks. Results showed that the concurrent use of the BCI system during the flight simulation does not affect the flight performances. However, BCI performances decrease from the 83 to 63 % while attending additional alertness and vigilance tasks. This work shows that it is possible to successfully control a BCI system during the execution of multiple tasks such as piloting a flight simulator with an extra cognitive load induced by attentional tasks. Such framework aims to foster the knowledge on BCI systems embedded into vehicles and robotic devices to allow the simultaneous execution of secondary tasks.

  9. Investigation of the effect of EEG-BCI on the simultaneous execution of flight simulation and attentional tasks.

    PubMed

    Vecchiato, Giovanni; Borghini, Gianluca; Aricò, Pietro; Graziani, Ilenia; Maglione, Anton Giulio; Cherubino, Patrizia; Babiloni, Fabio

    2016-10-01

    Brain-computer interfaces (BCIs) are widely used for clinical applications and exploited to design robotic and interactive systems for healthy people. We provide evidence to control a sensorimotor electroencephalographic (EEG) BCI system while piloting a flight simulator and attending a double attentional task simultaneously. Ten healthy subjects were trained to learn how to manage a flight simulator, use the BCI system, and answer to the attentional tasks independently. Afterward, the EEG activity was collected during a first flight where subjects were required to concurrently use the BCI, and a second flight where they were required to simultaneously use the BCI and answer to the attentional tasks. Results showed that the concurrent use of the BCI system during the flight simulation does not affect the flight performances. However, BCI performances decrease from the 83 to 63 % while attending additional alertness and vigilance tasks. This work shows that it is possible to successfully control a BCI system during the execution of multiple tasks such as piloting a flight simulator with an extra cognitive load induced by attentional tasks. Such framework aims to foster the knowledge on BCI systems embedded into vehicles and robotic devices to allow the simultaneous execution of secondary tasks. PMID:26645694

  10. Task switching in a hierarchical task structure: evidence for the fragility of the task repetition benefit

    NASA Technical Reports Server (NTRS)

    Lien, Mei-Ching; Ruthruff, Eric

    2004-01-01

    This study examined how task switching is affected by hierarchical task organization. Traditional task-switching studies, which use a constant temporal and spatial distance between each task element (defined as a stimulus requiring a response), promote a flat task structure. Using this approach, Experiment 1 revealed a large switch cost of 238 ms. In Experiments 2-5, adjacent task elements were grouped temporally and/or spatially (forming an ensemble) to create a hierarchical task organization. Results indicate that the effect of switching at the ensemble level dominated the effect of switching at the element level. Experiments 6 and 7, using an ensemble of 3 task elements, revealed that the element-level switch cost was virtually absent between ensembles but was large within an ensemble. The authors conclude that the element-level task repetition benefit is fragile and can be eliminated in a hierarchical task organization.

  11. The task force process

    SciTech Connect

    Applegate, J.S.

    1995-01-31

    This paper focuses on the unique aspects of the Fernald Citizens Task Force process that have contributed to a largely successful public participation effort at Fernald. The Fernald Citizens Task Force passed quickly by many procedural issues. Instead, the Task Force concentrated on (a) educating itself about the site, its problems, and possible solutions, and (b) choosing a directed way to approach its mandate: To make recommendations on several {open_quotes}big picture{close_quotes} issues, including future use of the site, cleanup levels, waste disposition, and cleanup priorities. This paper presents the approach used at Fernald for establishing and running a focused site-specific advisory board, the key issues that have been faced, and how these issues were resolved. The success of Fernald in establishing a strong and functioning site-specific advisory board serves as a useful model for other DOE facilities, although the Fernald model is just one of many approaches that can be taken. However, the approach presented here has worked extremely well for Fernald.

  12. Mobile Thread Task Manager

    NASA Technical Reports Server (NTRS)

    Clement, Bradley J.; Estlin, Tara A.; Bornstein, Benjamin J.

    2013-01-01

    The Mobile Thread Task Manager (MTTM) is being applied to parallelizing existing flight software to understand the benefits and to develop new techniques and architectural concepts for adapting software to multicore architectures. It allocates and load-balances tasks for a group of threads that migrate across processors to improve cache performance. In order to balance-load across threads, the MTTM augments a basic map-reduce strategy to draw jobs from a global queue. In a multicore processor, memory may be "homed" to the cache of a specific processor and must be accessed from that processor. The MTTB architecture wraps access to data with thread management to move threads to the home processor for that data so that the computation follows the data in an attempt to avoid L2 cache misses. Cache homing is also handled by a memory manager that translates identifiers to processor IDs where the data will be homed (according to rules defined by the user). The user can also specify the number of threads and processors separately, which is important for tuning performance for different patterns of computation and memory access. MTTM efficiently processes tasks in parallel on a multiprocessor computer. It also provides an interface to make it easier to adapt existing software to a multiprocessor environment.

  13. Generic cognitive adaptations to task interference in task switching.

    PubMed

    Poljac, Edita; Bekkering, Harold

    2009-11-01

    The present study investigated how the activation of previous tasks interferes with the execution of future tasks as a result of temporal manipulations. Color and shape matching tasks were organized in runs of two trials each. The tasks were specified by a cue presented before a task run, cueing only the first trials of each run. Response times (RTs) and error rates were measured for task switching and task repetition conditions. Task interference was varied as a function of response-cue interval (RCI of 300 and 900ms), that is, the interval between the task runs. Keeping the response-stimulus interval within the task runs constant at 300ms allowed the disentangling of the direct effects of RCI manipulation on performance (first trials) from the general effects on performance (both trials in the run). The data showed similar performance improvement due to RCI increase on both trials in the task run. Furthermore, increasing RCI improved both switch and repetition performance to a similar extent. Together, our findings provide further evidence for accounts stressing generic effects of proactive task interference in task switching.

  14. Task-specific effects of reward on task switching.

    PubMed

    Umemoto, Akina; Holroyd, Clay B

    2015-07-01

    Although cognitive control and reinforcement learning have been researched extensively over the last few decades, only recently have studies investigated their interrelationship. An important unanswered question concerns how the control system decides what task to execute and how vigorously to carry out the task once selected. Based on a recent theory of control formulated according to principles of hierarchical reinforcement learning, we asked whether rewards can affect top-down control over task performance at the level of task representation. Participants were rewarded for correctly performing only one of two tasks in a standard task-switching experiment. Reaction times and error rates were lower for the reinforced task compared to the non-reinforced task. Moreover, the switch cost in error rates for the non-reinforced task was significantly larger compared to the reinforced task, especially for trials in which the imperative stimulus afforded different responses for the two tasks, resulting in a "non-paradoxical" asymmetric switch cost. These findings suggest that reinforcement at the task level resulted in greater application of top-down control rather than in stronger stimulus-response pathways for the rewarded task.

  15. Task frequency influences stimulus-driven effects on task selection during voluntary task switching.

    PubMed

    Arrington, Catherine M; Reiman, Kaitlin M

    2015-08-01

    Task selection during voluntary task switching involves both top-down (goal-directed) and bottom-up (stimulus-driven) mechanisms. The factors that shift the balance between these two mechanisms are not well characterized. In the present research, we studied the role that task frequency plays in determining the extent of stimulus-driven task selection. In two experiments, we used the basic paradigm adapted from Arrington (Memory & Cognition, 38, 991-997, 2008), in which the effect of stimulus availability serves as a marker of stimulus-driven task selection. A number and letter appeared on each trial with varying stimulus onset asynchronies, and participants performed either a consonant/vowel or an even/odd judgment. In Experiment 1, participants were instructed as to the relative frequency with which each task was to be performed (i.e., 50/50, 60/40, or 75/25) and were further instructed to make their transitions between tasks unpredictable. In Experiment 2, participants were given no instructions about how to select tasks, resulting in naturally occurring variation in task frequency. With both instructed (Exp. 1) and naturally occurring (Exp. 2) relative task frequencies, the less frequently performed task showed a greater effect of stimulus availability on task selection, suggestive of a larger influence of stimulus-driven mechanisms during task performance for the less frequent task. When goal-directed mechanisms of task choice are engaged less frequently, the relative influence of the stimulus environment increases. PMID:26106057

  16. Comparing features extractors in EEG-based cognitive fatigue detection of demanding computer tasks.

    PubMed

    Rifai Chai; Smith, Mitchell R; Nguyen, Tuan N; Sai Ho Ling; Coutts, Aaron J; Nguyen, Hung T

    2015-01-01

    An electroencephalography (EEG)-based classification system could be used as a tool for detecting cognitive fatigue from demanding computer tasks. The most widely used feature extractor in EEG-based fatigue classification is power spectral density (PSD). This paper investigates PSD and three alternative feature extraction methods, in order to find the best feature extractor for the classification of cognitive fatigue during cognitively demanding tasks. These compared methods are power spectral entropy (PSE), wavelet, and autoregressive (AR). Bayesian neural network was selected as the classifier in this study. The results showed that the use of PSD and PSE methods provide an average accuracy of 60% for each computer task. This finding is slightly improved using the wavelet method which has an average accuracy of 61%. The AR method is the best feature extractor compared with the PSD, PSE and wavelet in this study with accuracy of 75.95% in AX-continuous performance test (AX-CPT), 75.23% in psychomotor vigilance test (PVT) and 76.02% in Stroop task (p-value <; 0.05).

  17. Learner Mining of Pre-Task and Task Input

    ERIC Educational Resources Information Center

    Boston, Jeremy Scott

    2008-01-01

    The findings reported in this article suggest that learners inevitably "mine" wordings contained in pre-task and task materials when performing tasks, even when the teacher did not explicitly draw learner attention to these features. However, this was found to be true only with written materials, and learners did not appear to mine specific…

  18. Maximally Expressive Task Modeling

    NASA Technical Reports Server (NTRS)

    Japp, John; Davis, Elizabeth; Maxwell, Theresa G. (Technical Monitor)

    2002-01-01

    Planning and scheduling systems organize "tasks" into a timeline or schedule. The tasks are defined within the scheduling system in logical containers called models. The dictionary might define a model of this type as "a system of things and relations satisfying a set of rules that, when applied to the things and relations, produce certainty about the tasks that are being modeled." One challenging domain for a planning and scheduling system is the operation of on-board experiment activities for the Space Station. The equipment used in these experiments is some of the most complex hardware ever developed by mankind, the information sought by these experiments is at the cutting edge of scientific endeavor, and the procedures for executing the experiments are intricate and exacting. Scheduling is made more difficult by a scarcity of space station resources. The models to be fed into the scheduler must describe both the complexity of the experiments and procedures (to ensure a valid schedule) and the flexibilities of the procedures and the equipment (to effectively utilize available resources). Clearly, scheduling space station experiment operations calls for a "maximally expressive" modeling schema. Modeling even the simplest of activities cannot be automated; no sensor can be attached to a piece of equipment that can discern how to use that piece of equipment; no camera can quantify how to operate a piece of equipment. Modeling is a human enterprise-both an art and a science. The modeling schema should allow the models to flow from the keyboard of the user as easily as works of literature flowed from the pen of Shakespeare. The Ground Systems Department at the Marshall Space Flight Center has embarked on an effort to develop a new scheduling engine that is highlighted by a maximally expressive modeling schema. This schema, presented in this paper, is a synergy of technological advances and domain-specific innovations.

  19. Silicon material task review

    NASA Technical Reports Server (NTRS)

    Lorenz, J. H.

    1986-01-01

    The objectives of the Flat-plate Solar Array (FSA) Project Silicon Material Task are to evaluate technologies, new and old; to develop the most promising technologies; to establish practicality of the processes to meet production, energy use, and economic criteria; and to develop an information base on impurities in polysilicon and to determine their effects on solar cell performance. The approach involves determining process feasibility, setting milestones for the forced selection of the processes, and establishing the technical readiness of the integrated process.

  20. Quarternary tectonics, Task 1

    SciTech Connect

    Bell, J.W.

    1993-09-30

    Activities conducted for the evaluation of the geology and seismotectonics stability of Yucca Mountain as a potential site for the underground disposal of high-level radioactive wastes continued. Tasks concerned with quaternary tectonics include: scheduling of photography of Little Skull Mountain area; the collection and dating of rock varnish samples from the 1932 Cedar Mountain earthquake area for carbon 14 AMS and cation-ratio analysis; collection of samples for thermoluminescence dating from the 1932 Cedar Mountain earthquake area; mapping of the northern area of Crater Flat; and surveying of the May 17, 1993 Eureka the Valley earthquake area.

  1. Vigilance behaviour of the year-round territorial vicuña (Vicugna vicugna) outside the breeding season: influence of group size, social factors and distance to a water source.

    PubMed

    Torres, M Eugenia Mosca; Puig, Silvia; Novillo, Agustina; Ovejero, Ramiro

    2015-04-01

    We conducted focal observations of vicuña, a year-around territorial mammal, to compare vigilance behaviour between territorial and bachelor males outside the reproductive season. We hypothesized that the time spent vigilant would depend on male social status, considering the potential effects of several variables: sampling year, group size, distances to the nearest neighbour and to a vega (mountain wetland). We fit GLM models to assess how these variables, and their interactions, affected time allocation of territorial and bachelor males. We found non significant differences between territorial and bachelor males in the time devoted to vigilance behaviour. Vigilance of territorial males was influenced by the sampling year and the distance to the vega. In turn, vigilance in bachelor males was influenced mainly by the sampling year, the group size and the distance to the vega. Our results suggest that sampling year and distance to the vega are more important than social factors in conditioning the behaviour of male vicuñas, during the non-reproductive season. Future studies of behaviour in water-dependant ungulates, should consider the influence of water and forage availabilities, and the interactions between group size and other variables.

  2. Atomic Oxygen Task

    NASA Technical Reports Server (NTRS)

    Hadaway, James B.

    1997-01-01

    This report details work performed by the Center for Applied Optics (CAO) at the University of Alabama in Huntsville (UAH) on the contract entitled 'Atomic Oxygen Task' for NASA's Marshall Space Flight Center (contract NAS8-38609, Delivery Order 109, modification number 1). Atomic oxygen effects on exposed materials remain a critical concern in designing spacecraft to withstand exposure in the Low Earth Orbit (LEO) environment. The basic objective of atomic oxygen research in NASA's Materials & Processes (M&P) Laboratory is to provide the solutions to material problems facing present and future space missions. The objective of this work was to provide the necessary research for the design of specialized experimental test configurations and development of techniques for evaluating in-situ space environmental effects, including the effects of atomic oxygen and electromagnetic radiation on candidate materials. Specific tasks were performed to address materials issues concerning accelerated environmental testing as well as specifically addressing materials issues of particular concern for LDEF analysis and Space Station materials selection.

  3. Inhibition in Dot Comparison Tasks

    ERIC Educational Resources Information Center

    Clayton, Sarah; Gilmore, Camilla

    2015-01-01

    Dot comparison tasks are commonly used to index an individual's Approximate Number System (ANS) acuity, but the cognitive processes involved in completing these tasks are poorly understood. Here, we investigated how factors including numerosity ratio, set size and visual cues influence task performance. Forty-four children aged 7-9 years completed…

  4. Task Analysis: A Proactive Paradigm.

    ERIC Educational Resources Information Center

    Cipriano, Robert E.

    A sequential and developmental curriculum design is conceptualized, based on task analysis. Task analysis is a detailed inquiry into actions undertaken in performing specific tasks or jobs. Baseline data form a database on which education and training programs are designed, produced, and evaluated. The following are sources of information for task…

  5. Skill Components of Task Analysis

    ERIC Educational Resources Information Center

    Adams, Anne E.; Rogers, Wendy A.; Fisk, Arthur D.

    2013-01-01

    Some task analysis methods break down a task into a hierarchy of subgoals. Although an important tool of many fields of study, learning to create such a hierarchy (redescription) is not trivial. To further the understanding of what makes task analysis a skill, the present research examined novices' problems with learning Hierarchical Task…

  6. Task-Based Information Searching.

    ERIC Educational Resources Information Center

    Vakkari, Pertti

    2003-01-01

    Reviews studies on the relationship between task performance and information searching by end-users, focusing on information searching in electronic environments and information retrieval systems. Topics include task analysis; task characteristics; search goals; modeling information searching; modeling search goals; information seeking behavior;…

  7. TASK: Let's Have a Party!

    ERIC Educational Resources Information Center

    Rees, James

    2012-01-01

    In this article, the author describes a creative way to demystify contemporary art for students. TASK is artist Oliver Herring's creation, where participants actively interpret instructions found on little pieces of paper--what he calls "tasks." An art classroom has all the key ingredients for a TASK event: (1) people; (2) materials; (3) space;…

  8. Principles of Communicative Task Design.

    ERIC Educational Resources Information Center

    Nunan, David

    The use of the learning task as a basic planning and instructional tool for communicative second language instruction is discussed, and considerations and procedures for designing such tasks are outlined. A task is defined as a piece of classroom work that involves learners in comprehending, manipulating, producing, or interacting in the target…

  9. Word Fluency: A Task Analysis.

    ERIC Educational Resources Information Center

    Laine, Matti

    It is suggested that models of human problem solving are useful in the analysis of word fluency (WF) test performance. In problem-solving terms, WF tasks would require the subject to define and clarify the conditions of the task (task acquisition), select and employ appropriate strategies, and monitor one's performance. In modern neuropsychology,…

  10. Designing Probabilistic Tasks for Kindergartners

    ERIC Educational Resources Information Center

    Skoumpourdi, Chrysanthi; Kafoussi, Sonia; Tatsis, Konstantinos

    2009-01-01

    Recent research suggests that children could be engaged in probability tasks at an early age and task characteristics seem to play an important role in the way children perceive an activity. To this direction in the present article we investigate the role of some basic characteristics of probabilistic tasks in their design and implementation. In…

  11. Component Processes in Task Switching.

    ERIC Educational Resources Information Center

    Meiran, Nachshon; Chorev, Ziv; Sapir, Ayelet

    2000-01-01

    Studied task switching in 4 experiments involving 111 Israeli undergraduates. Results show the preparation for a task switch is not a by-product of general preparation by phasic alertness or predicting target onset and establish reconfiguration as a separate preparatory process. Suggests that there are at least three components of task switching…

  12. Elementary derivative tasks and neural net multiscale analysis of tasks.

    PubMed

    Giraud, B G; Touzeau, A

    2002-01-01

    Formal neurons implementing wavelets have been shown to build nets that are able to approximate any multidimensional task. In this paper, we use a finite number of formal neurons implementing elementary tasks such as "sombrero" responses or even simpler "window" responses, with adjustable widths. We show this to provide a reasonably efficient, practical and robust, multifrequency analysis of tasks. The translation degree of freedom of wavelets is shown to be unnecessary. A training algorithm, optimizing the output task with respect to the widths of the responses, reveals two distinct training modes. The first mode keeps the formal neurons distinct. The other mode induces some of the formal neurons to become identical, with output weights of equal strengths but opposite signs. Hence this latter mode promotes tasks that are derivatives of the elementary tasks with respect to the width parameter. Such results, obtained from optimizations with respect to a width parameter, can be generalized for any other parameters of the elementary tasks.

  13. Task Analysis Technologies at KSC

    NASA Technical Reports Server (NTRS)

    Carstens, Deborah S.

    2003-01-01

    Project objective: (1) Form an integrated team of NASA. USA, Boeing, and Dynacs researches. (2) Create a user friendly software prototype that assists an analyst in performing a human factors process failure modes and effects analysis (HF-PFMEA). (3)Perform four task analyses on center: cargo late access task analysis (NASA/Boeing team); payload test and verification system task analysis (NASA/Boeing team); slammer cover installation operations task analysis (NASA/USA team); ATDC LOX pump acceptance test procedure task analysis (NASA/Dynacs team).

  14. Exploring the role of vision in social foraging: what happens to group size, vigilance, spacing, aggression and habitat use in birds and mammals that forage at night?

    PubMed

    Beauchamp, Guy

    2007-08-01

    I examined the role of vision in social foraging by contrasting group size, vigilance, spacing, aggression and habitat use between day and night in many species of birds and mammals. The literature review revealed that the rate of predation/disturbance was often reduced at night while food was considered more available. Social foraging at night was prevalent in many species suggesting that low light levels at night are not sufficient to prevent the formation and cohesion of animal groups. Group sizes were similar or larger at night than during the day in more than half the bird populations and in the majority of mammal populations. Factors such as calls, feeding noises or smells may contribute to the formation and cohesion of groups at night. Larger numbers of foragers at night may also facilitate the aggregation of more foragers. Vigilance levels were usually lower at night perhaps as a response to the lower predation risk or to the decreased value of scanning for predators that are difficult to locate. Low light levels may also make visual cues that promote aggression less conspicuous, which may be a factor in the lower levels of aggression documented at night. Spacing varied as a function of time of day in response to changes in foraging mode or food availability. Habitats that are avoided during the day were often used at night. Foraging at night presents birds and mammals with a new set of constraints that influence group size, time budgeting and habitat use.

  15. Task directed sensing

    NASA Technical Reports Server (NTRS)

    Firby, R. James

    1990-01-01

    High-level robot control research must confront the limitations imposed by real sensors if robots are to be controlled effectively in the real world. In particular, sensor limitations make it impossible to maintain a complete, detailed world model of the situation surrounding the robot. To address the problems involved in planning with the resulting incomplete and uncertain world models, traditional robot control architectures must be altered significantly. Task-directed sensing and control is suggested as a way of coping with world model limitations by focusing sensing and analysis resources on only those parts of the world relevant to the robot's active goals. The RAP adaptive execution system is used as an example of a control architecture designed to deploy sensing resources in this way to accomplish both action and knowledge goals.

  16. The Effect of Hierarchical Task Representations on Task Selection in Voluntary Task Switching

    ERIC Educational Resources Information Center

    Weaver, Starla M.; Arrington, Catherine M.

    2013-01-01

    The current study explored the potential for hierarchical representations to influence action selection during voluntary task switching. Participants switched between 4 individual task elements. In Experiment 1, participants were encouraged to represent the task elements as grouped within a hierarchy based on experimental manipulations of varying…

  17. AMU NEXRAD Exploitation Task

    NASA Technical Reports Server (NTRS)

    Lambert, Winifred C.; Wheeler, Mark M.

    1997-01-01

    This report documents the results of the Applied Meteorology Unit's NEXRAD Exploitation Task. The objectives of this task are to determine what radar signatures are present prior to and at the time of convection initiation, and to determine radar signatures which will help distinguish whether the ensuing convection will become severe. Radar data from the WSR-88D radar located at NWS Melbourne (WSR-88D/KMLB) were collected between June and September 1995, and 16 convective case studies were analyzed for which the radar was operating during the entire period of interest. All WSR-88D/KMLB products were scrutinized for their utility in detecting convection initiation and severe storm signatures. Through process of elimination, it was found that the 0.5 deg reflectivity product with the lowest reflectivity values displayed is the best product to monitor for convection initiation signatures. Seven meteorological features associated with the initiation of deep convection were identified: the Merritt Island and Indian River convergence zones, interlake convergence, horizontal convective rolls, the sea breeze, storm outflow boundaries, and fires. Their reflectivity values ranged from -5 to 20 dBZ. Of the three severe weather phenomena (winds greater than or equal to 50 kts, tornado, 3/4 inch hail), high wind events due to microbursts were most common in the data set. It was found that the values and trends of composite reflectivity, vertically integrated liquid, and core aspect ratio were key indicators of the potential of a cell to produce a microburst. The data were not analyzed for the other two severe weather phenomena because they rarely occurred during the data collection period. This report also includes suggestions for new WSR-88D products, summaries of ongoing research aimed at creating new products, and explicit recommended procedures for detecting convection initiation and severe storm signatures in the radar data using the currently available technology.

  18. The influence of herd size, conspecific risk, and predation risk on the vigilance of elk (Cervus elaphus) in Yellowstone National Park, and, Interest, learning, and a thematic biology course

    NASA Astrophysics Data System (ADS)

    Lung, Mark A.

    This dissertation is a composite of biological and educational research. The biological research concerns Rocky Mountain elk (Cervus elaphus ) behavior. The educational research presents ideas and findings on the influence of a thematic general biology course on student interest and perception of learning. The dissertation begins with a Preface that attempts to bring the ideas presented in later chapters together. Chapter One is a review of the literature concerning sociality, social behaviors, and elk biology. It summarizes current research literature as a means of introduction to Chapter Two. Chapter Two presents findings concerning the effects of herd size, predation risk, and the risk of being near conspecifics on two behaviors commonly associated with social animals---vigilance and aggression. Vigilance and aggression were measured in elk in Yellowstone National Park in two regions that varied in their presence of elk predators (wolves---Canis lupus, and grizzly bears---Ursus arctos) and in two seasons (spring and fall) that varied in the risks of being near conspecifics. Overall, male and female elk responded very differently. Male elk adjust their vigilance and aggression in response to changes in conspecific risk, but not to changes in predation risk. Female elk adjust their vigilance in response to changes in predation risk, but not to changes in conspecific risk. Males show no response in vigilance to changes in herd size. Non-reproductive females, however, adjust their levels of vigilance with changes in herd size in high risk regions. Interestingly, in the spring, vigilance decreases with increasing herd size, but in the fall, vigilance increases with increasing herd size. Chapter Three presents findings concerning the influence of a thematic course design on student perceptions of interest and teaming in a non-major's biology course (Bins 100: Concepts of Biology). I compared responses on student evaluations from two sections of Bios 100 taught in a

  19. Task Prioritization in Dual-Tasking: Instructions versus Preferences.

    PubMed

    Jansen, Reinier J; van Egmond, René; de Ridder, Huib

    2016-01-01

    The role of task prioritization in performance tradeoffs during multi-tasking has received widespread attention. However, little is known on whether people have preferences regarding tasks, and if so, whether these preferences conflict with priority instructions. Three experiments were conducted with a high-speed driving game and an auditory memory task. In Experiment 1, participants did not receive priority instructions. Participants performed different sequences of single-task and dual-task conditions. Task performance was evaluated according to participants' retrospective accounts on preferences. These preferences were reformulated as priority instructions in Experiments 2 and 3. The results showed that people differ in their preferences regarding task prioritization in an experimental setting, which can be overruled by priority instructions, but only after increased dual-task exposure. Additional measures of mental effort showed that performance tradeoffs had an impact on mental effort. The interpretation of these findings was used to explore an extension of Threaded Cognition Theory with Hockey's Compensatory Control Model. PMID:27391779

  20. Task Prioritization in Dual-Tasking: Instructions versus Preferences

    PubMed Central

    Jansen, Reinier J.; van Egmond, René; de Ridder, Huib

    2016-01-01

    The role of task prioritization in performance tradeoffs during multi-tasking has received widespread attention. However, little is known on whether people have preferences regarding tasks, and if so, whether these preferences conflict with priority instructions. Three experiments were conducted with a high-speed driving game and an auditory memory task. In Experiment 1, participants did not receive priority instructions. Participants performed different sequences of single-task and dual-task conditions. Task performance was evaluated according to participants’ retrospective accounts on preferences. These preferences were reformulated as priority instructions in Experiments 2 and 3. The results showed that people differ in their preferences regarding task prioritization in an experimental setting, which can be overruled by priority instructions, but only after increased dual-task exposure. Additional measures of mental effort showed that performance tradeoffs had an impact on mental effort. The interpretation of these findings was used to explore an extension of Threaded Cognition Theory with Hockey’s Compensatory Control Model. PMID:27391779

  1. Task Prioritization in Dual-Tasking: Instructions versus Preferences.

    PubMed

    Jansen, Reinier J; van Egmond, René; de Ridder, Huib

    2016-01-01

    The role of task prioritization in performance tradeoffs during multi-tasking has received widespread attention. However, little is known on whether people have preferences regarding tasks, and if so, whether these preferences conflict with priority instructions. Three experiments were conducted with a high-speed driving game and an auditory memory task. In Experiment 1, participants did not receive priority instructions. Participants performed different sequences of single-task and dual-task conditions. Task performance was evaluated according to participants' retrospective accounts on preferences. These preferences were reformulated as priority instructions in Experiments 2 and 3. The results showed that people differ in their preferences regarding task prioritization in an experimental setting, which can be overruled by priority instructions, but only after increased dual-task exposure. Additional measures of mental effort showed that performance tradeoffs had an impact on mental effort. The interpretation of these findings was used to explore an extension of Threaded Cognition Theory with Hockey's Compensatory Control Model.

  2. Hypercube matrix computation task

    NASA Technical Reports Server (NTRS)

    Calalo, R.; Imbriale, W.; Liewer, P.; Lyons, J.; Manshadi, F.; Patterson, J.

    1987-01-01

    The Hypercube Matrix Computation (Year 1986-1987) task investigated the applicability of a parallel computing architecture to the solution of large scale electromagnetic scattering problems. Two existing electromagnetic scattering codes were selected for conversion to the Mark III Hypercube concurrent computing environment. They were selected so that the underlying numerical algorithms utilized would be different thereby providing a more thorough evaluation of the appropriateness of the parallel environment for these types of problems. The first code was a frequency domain method of moments solution, NEC-2, developed at Lawrence Livermore National Laboratory. The second code was a time domain finite difference solution of Maxwell's equations to solve for the scattered fields. Once the codes were implemented on the hypercube and verified to obtain correct solutions by comparing the results with those from sequential runs, several measures were used to evaluate the performance of the two codes. First, a comparison was provided of the problem size possible on the hypercube with 128 megabytes of memory for a 32-node configuration with that available in a typical sequential user environment of 4 to 8 megabytes. Then, the performance of the codes was anlyzed for the computational speedup attained by the parallel architecture.

  3. Hypercube matrix computation task

    NASA Technical Reports Server (NTRS)

    Calalo, Ruel H.; Imbriale, William A.; Jacobi, Nathan; Liewer, Paulett C.; Lockhart, Thomas G.; Lyzenga, Gregory A.; Lyons, James R.; Manshadi, Farzin; Patterson, Jean E.

    1988-01-01

    A major objective of the Hypercube Matrix Computation effort at the Jet Propulsion Laboratory (JPL) is to investigate the applicability of a parallel computing architecture to the solution of large-scale electromagnetic scattering problems. Three scattering analysis codes are being implemented and assessed on a JPL/California Institute of Technology (Caltech) Mark 3 Hypercube. The codes, which utilize different underlying algorithms, give a means of evaluating the general applicability of this parallel architecture. The three analysis codes being implemented are a frequency domain method of moments code, a time domain finite difference code, and a frequency domain finite elements code. These analysis capabilities are being integrated into an electromagnetics interactive analysis workstation which can serve as a design tool for the construction of antennas and other radiating or scattering structures. The first two years of work on the Hypercube Matrix Computation effort is summarized. It includes both new developments and results as well as work previously reported in the Hypercube Matrix Computation Task: Final Report for 1986 to 1987 (JPL Publication 87-18).

  4. Task-dependent color discrimination

    NASA Technical Reports Server (NTRS)

    Poirson, Allen B.; Wandell, Brian A.

    1990-01-01

    When color video displays are used in time-critical applications (e.g., head-up displays, video control panels), the observer must discriminate among briefly presented targets seen within a complex spatial scene. Color-discrimination threshold are compared by using two tasks. In one task the observer makes color matches between two halves of a continuously displayed bipartite field. In a second task the observer detects a color target in a set of briefly presented objects. The data from both tasks are well summarized by ellipsoidal isosensitivity contours. The fitted ellipsoids differ both in their size, which indicates an absolute sensitivity difference, and orientation, which indicates a relative sensitivity difference.

  5. Correlates of academic procrastination: discomfort, task aversiveness, and task capability.

    PubMed

    Milgram, N; Marshevsky, S; Sadeh, C

    1995-03-01

    The relationships among five aspects of academic procrastination--behavioral delay, personal upset about the delay, task aversiveness, task capability, and the desire to reduce behavioral delay--were investigated in 10th-grade Israeli students (N = 195). Upset about delay was weakly related to delay itself, and--unlike delay--was strongly related to perceived capability to perform academic tasks and to the desire to change delaying behavior. Students delayed more on academic tasks labeled unpleasant than pleasant, were neutral in between, and were correspondingly more upset about the former than the latter. They more frequently acknowledged reasons for academic procrastination that were less threatening to their self-image (e.g., problems in time management) than reasons that were more threatening (e.g., lack of ability). Interest in reducing delay is related more to self-perceived ability to handle tasks than to time spent procrastinating or reasons given for procrastinating.

  6. Functional Activation during the Rapid Visual Information Processing Task in a Middle Aged Cohort: An fMRI Study.

    PubMed

    Neale, Chris; Johnston, Patrick; Hughes, Matthew; Scholey, Andrew

    2015-01-01

    The Rapid Visual Information Processing (RVIP) task, a serial discrimination task where task performance believed to reflect sustained attention capabilities, is widely used in behavioural research and increasingly in neuroimaging studies. To date, functional neuroimaging research into the RVIP has been undertaken using block analyses, reflecting the sustained processing involved in the task, but not necessarily the transient processes associated with individual trial performance. Furthermore, this research has been limited to young cohorts. This study assessed the behavioural and functional magnetic resonance imaging (fMRI) outcomes of the RVIP task using both block and event-related analyses in a healthy middle aged cohort (mean age = 53.56 years, n = 16). The results show that the version of the RVIP used here is sensitive to changes in attentional demand processes with participants achieving a 43% accuracy hit rate in the experimental task compared with 96% accuracy in the control task. As shown by previous research, the block analysis revealed an increase in activation in a network of frontal, parietal, occipital and cerebellar regions. The event related analysis showed a similar network of activation, seemingly omitting regions involved in the processing of the task (as shown in the block analysis), such as occipital areas and the thalamus, providing an indication of a network of regions involved in correct trial performance. Frontal (superior and inferior frontal gryi), parietal (precuenus, inferior parietal lobe) and cerebellar regions were shown to be active in both the block and event-related analyses, suggesting their importance in sustained attention/vigilance. These networks and the differences between them are discussed in detail, as well as implications for future research in middle aged cohorts. PMID:26488289

  7. Functional Activation during the Rapid Visual Information Processing Task in a Middle Aged Cohort: An fMRI Study

    PubMed Central

    Neale, Chris; Johnston, Patrick; Hughes, Matthew; Scholey, Andrew

    2015-01-01

    The Rapid Visual Information Processing (RVIP) task, a serial discrimination task where task performance believed to reflect sustained attention capabilities, is widely used in behavioural research and increasingly in neuroimaging studies. To date, functional neuroimaging research into the RVIP has been undertaken using block analyses, reflecting the sustained processing involved in the task, but not necessarily the transient processes associated with individual trial performance. Furthermore, this research has been limited to young cohorts. This study assessed the behavioural and functional magnetic resonance imaging (fMRI) outcomes of the RVIP task using both block and event-related analyses in a healthy middle aged cohort (mean age = 53.56 years, n = 16). The results show that the version of the RVIP used here is sensitive to changes in attentional demand processes with participants achieving a 43% accuracy hit rate in the experimental task compared with 96% accuracy in the control task. As shown by previous research, the block analysis revealed an increase in activation in a network of frontal, parietal, occipital and cerebellar regions. The event related analysis showed a similar network of activation, seemingly omitting regions involved in the processing of the task (as shown in the block analysis), such as occipital areas and the thalamus, providing an indication of a network of regions involved in correct trial performance. Frontal (superior and inferior frontal gryi), parietal (precuenus, inferior parietal lobe) and cerebellar regions were shown to be active in both the block and event-related analyses, suggesting their importance in sustained attention/vigilance. These networks and the differences between them are discussed in detail, as well as implications for future research in middle aged cohorts. PMID:26488289

  8. Dimensions of school climate: teachers' or principals' power styles and subjects' propensities to be climate vigilant as related to students' perceptions of satisfaction and of peers' abusive behavior.

    PubMed

    Verhoek-Miller, Nancy; Miller, Duane I; Shirachi, Miyoko; Hoda, Nicholas

    2002-08-01

    Two studies investigated teachers' and principals' power styles as related to college students' retrospective ratings of satisfaction and peers' abusive behavior. One study also investigated retrospective self-perception as related to students' sensitivity to the occurrence of physical and psychological abuse in the school environment. Among the findings were positive correlations between subjects' perceptions that their typical elementary school teacher used referent, legitimate, or expert power styles and subjects' reported satisfaction with their elementary school experience. Small but statistically significant correlations were found suggesting that principals' power style was weakly associated with ratings of psychological abuse in elementary school and physical abuse in middle school. Also, students who rated themselves as intelligent, sensitive, attractive, and depressive had higher ratings of perceived psychological and physical abuse at school. It was concluded that parameters of leaders' power styles and subjects' vigilance might be useful for understanding school climates. Experimentally designed studies are required.

  9. Task Models in the Digital Ocean

    ERIC Educational Resources Information Center

    DiCerbo, Kristen E.

    2014-01-01

    The Task Model is a description of each task in a workflow. It defines attributes associated with that task. The creation of task models becomes increasingly important as the assessment tasks become more complex. Explicitly delineating the impact of task variables on the ability to collect evidence and make inferences demands thoughtfulness from…

  10. Students' Engagement in Literacy Tasks

    ERIC Educational Resources Information Center

    Parsons, Seth A.; Malloy, Jacquelynn A.; Parsons, Allison Ward; Burrowbridge, Sarah Cohen

    2015-01-01

    This article offers insight into what makes literacy tasks engaging or disengaging based on observations of and interviews with students. In a yearlong study of a sixth-grade classroom in a Title I school, students engaged in integrated literacy-social studies instruction. Researchers studied the degree of task openness and the degree to which…

  11. Maximize Student Time on Task

    ERIC Educational Resources Information Center

    Peters, Erin

    2004-01-01

    Student time on task is the most influential factor in student achievement. High motivation and engagement in learning have consistently been linked to increased levels of student success. At the same time, a lack of interest in schoolwork becomes increasingly common in more and more middle school students. To maximize time on task, teachers need…

  12. Creativity, Overinclusion, and Everyday Tasks

    ERIC Educational Resources Information Center

    Ottemiller, Dylan D.; Elliott, Colette Seter; Giovannetti, Tania

    2014-01-01

    This study examined relations between creative thinking and performance on routine, everyday tasks. Results were considered in light of past research on the putative relation between creativity and schizophrenia/psychotic thinking. Thirty healthy undergraduates completed the Alternative Uses Task, a measure of divergent thinking, and the 2 × 3…

  13. Cosmetology Series. Duty Task List.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This document contains the occupational duty/task lists for three occupations in the cosmetology series. Each occupation is divided into a number of duties. A separate page for each duty in the occupation lists the tasks in that duty along with its code number and columns to indicate whether that particular duty has been taught and to provide…

  14. Teachers' Aides: Tasks and Concerns

    ERIC Educational Resources Information Center

    Balderson, James H.; Nixon, Mary

    1976-01-01

    Addresses three questions: (1) What tasks do aides perform? (2) Does training make a difference in the type of tasks aides perform? (3) What are the concerns of aides? (Available from the Department of Educational Administration, The University of Alberta, Edmonton, Alberta, Canada T6G 2G5; $0.50, single copy.) (Author/IRT)

  15. Science 102: This Month's Task

    ERIC Educational Resources Information Center

    Robertson, Bill

    2015-01-01

    This task asks readers to figure out why when you stir a cup of hot liquid and tap on the side of the cup with a spoon, the pitch of sound starts low and ends up high. The solution to last month's tasks relating to the circumference of the Earth and how many stars are in the (visible) sky is also presented.

  16. Drafting Series. Duty Task List.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This task list is intended for use in planning and/or evaluating a competency-based course in drafting. The tasks required to perform the duties of seven types of drafters (i.e., general, architectural, electronic, civil, structural, mechanical, and process pipe drafters) and technical illustrators are outlined. The following are among the duties…

  17. Receptionist: Task List Competency Record.

    ERIC Educational Resources Information Center

    Minnesota Instructional Materials Center, White Bear Lake.

    One of a series of 12 in the secretarial/clerical area, this booklet for the vocational instructor contains a job description for the receptionist, a task list of areas of competency, an occupational tasks competency record (suggested as replacement for the traditional report card), a list of industry representatives and educators involved in…

  18. TASK: Anarchy in the Artroom

    ERIC Educational Resources Information Center

    Schubert, Cynthia; Van Patten, Kelda

    2012-01-01

    Most teenagers do not really like to be told what to do. For that matter, most adults don't either. This article discusses contemporary artist Oliver Herring's TASK, which is an opportunity for participants to bend or define the rules on their own terms. It is about choice, and, for many, it is a dream come true. TASK is controlled chaos that can…

  19. What Makes a Rich Task?

    ERIC Educational Resources Information Center

    Griffin, Pete

    2009-01-01

    A common view seems to be emerging in the mathematics education world at the moment that the development and use of "rich tasks" is a good thing; a "right thing" to do. There are many examples of these "rich tasks" and teachers are encouraged to use them whenever they can. Professional learners don't just accept this uncritically, but question…

  20. Decision paths in complex tasks

    NASA Technical Reports Server (NTRS)

    Galanter, Eugene

    1991-01-01

    Complex real world action and its prediction and control has escaped analysis by the classical methods of psychological research. The reason is that psychologists have no procedures to parse complex tasks into their constituents. Where such a division can be made, based say on expert judgment, there is no natural scale to measure the positive or negative values of the components. Even if we could assign numbers to task parts, we lack rules i.e., a theory, to combine them into a total task representation. We compare here two plausible theories for the amalgamation of the value of task components. Both of these theories require a numerical representation of motivation, for motivation is the primary variable that guides choice and action in well-learned tasks. We address this problem of motivational quantification and performance prediction by developing psychophysical scales of the desireability or aversiveness of task components based on utility scaling methods (Galanter 1990). We modify methods used originally to scale sensory magnitudes (Stevens and Galanter 1957), and that have been applied recently to the measure of task 'workload' by Gopher and Braune (1984). Our modification uses utility comparison scaling techniques which avoid the unnecessary assumptions made by Gopher and Braune. Formula for the utility of complex tasks based on the theoretical models are used to predict decision and choice of alternate paths to the same goal.

  1. Task Switching: A PDP Model

    ERIC Educational Resources Information Center

    Gilbert, Sam J.; Shallice, Tim

    2002-01-01

    When subjects switch between a pair of stimulus-response tasks, reaction time is slower on trial N if a different task was performed on trial N--1. We present a parallel distributed processing (PDP) model that simulates this effect when subjects switch between word reading and color naming in response to Stroop stimuli. Reaction time on "switch…

  2. Electricity Series. Duty Task List.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This task list is intended for use in planning and/or evaluating a competency-based course in electricity. The guide outlines the tasks entailed in 10 different duties typically required of employees in the following occupations: residential electrician apprentice, material handler/supply clerk, maintenance electrician apprentice,…

  3. Putting Mathematical Tasks into Context

    ERIC Educational Resources Information Center

    Nagle, Courtney R.; Styers, Jodie L.

    2015-01-01

    Although many factors affect students' mathematical activity during a lesson, the teacher's selection and implementation of tasks is arguably the most influential in determining the level of student engagement. Mathematical tasks are intended to focus students' attention on a particular mathematical concept and it is the careful developing and…

  4. Welding Series. Duty Task List.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This document contains the occupational duty/task lists for six occupations in the welding series. Each occupation is divided into a number of duties. A separate page for each duty in the occupation lists the tasks in that duty along with its code number and columns to indicate whether that particular duty has been taught and to provide space for…

  5. Horticulture Series. Duty Task List.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This document contains the occupational duty/task lists for 9 occupations in the horticulture series. Each occupation is divided into a number of duties. A separate page for each duty in the occupation lists the tasks in that duty along with its code number and columns to indicate whether that particular duty has been taught and to provide space…

  6. Task Attention Facilitates Learning of Task-Irrelevant Stimuli

    PubMed Central

    Huang, Tsung-Ren; Watanabe, Takeo

    2012-01-01

    Attention plays a fundamental role in visual learning and memory. One highly established principle of visual attention is that the harder a central task is, the more attentional resources are used to perform the task and the smaller amount of attention is allocated to peripheral processing because of limited attention capacity. Here we show that this principle holds true in a dual-task setting but not in a paradigm of task-irrelevant perceptual learning. In Experiment 1, eight participants were asked to identify either bright or dim number targets at the screen center and to remember concurrently presented scene backgrounds. Their recognition performances for scenes paired with dim/hard targets were worse than those for scenes paired with bright/easy targets. In Experiment 2, eight participants were asked to identify either bright or dim letter targets at the screen center while a task-irrelevant coherent motion was concurrently presented in the background. After five days of training on letter identification, participants improved their motion sensitivity to the direction paired with hard/dim targets improved but not to the direction paired with easy/bright targets. Taken together, these results suggest that task-irrelevant stimuli are not subject to the attentional control mechanisms that task-relevant stimuli abide. PMID:22563424

  7. Materials processing in space programs tasks. [NASA research tasks

    NASA Technical Reports Server (NTRS)

    Pentecost, E.

    1981-01-01

    Active research tasks as of the end of fiscal year 1981 of the materials processing in space program, NASA Office of Space and Terrestrial Applications are summarized to provide an overview of the program scope for managers and scientists in industry, university, and government communities. The program, its history, strategy, and overall goal are described the organizational structures and people involved are identified and a list of recent publications is given for each research task. Four categories: Crystal Growth; Solidification of Metals, Alloys, and Composites; Fluids, Transports, and Chemical Processes, and Ultrahigh Vacuum and Containerless Processing Technologies are used to group the tasks. Some tasks are placed in more than one category to insure complete coverage of each category.

  8. Multiple paths in complex tasks

    NASA Technical Reports Server (NTRS)

    Galanter, Eugene; Wiegand, Thomas; Mark, Gloria

    1987-01-01

    The relationship between utility judgments of subtask paths and the utility of the task as a whole was examined. The convergent validation procedure is based on the assumption that measurements of the same quantity done with different methods should covary. The utility measures of the subtasks were obtained during the performance of an aircraft flight controller navigation task. Analyses helped decide among various models of subtask utility combination, whether the utility ratings of subtask paths predict the whole tasks utility rating, and indirectly, whether judgmental models need to include the equivalent of cognitive noise.

  9. Non-image forming effects of illuminance level: Exploring parallel effects on physiological arousal and task performance.

    PubMed

    Huiberts, Laura M; Smolders, Karin C H J; de Kort, Yvonne A W

    2016-10-01

    This study investigated diurnal non-image forming (NIF) effects of illuminance level on physiological arousal in parallel to NIF effects on vigilance and working memory performance. We employed a counterbalanced within-subjects design in which thirty-nine participants (mean age=21.2; SD=2.1; 11 male) completed three 90-min sessions (165 vs. 600lx vs. 1700lx at eye level) either in the morning (N=18) or afternoon (N=21). During each session, participants completed four measurement blocks (incl. one baseline block) each consisting of a 10-min Psychomotor Vigilance Task (PVT) and a Backwards Digit-Span Task (BDST) including easy trials (4-6 digits) and difficult trials (7-8 digits). Heart rate (HR), skin conductance level (SCL) and systolic blood pressure (SBP) were measured continuously. The results revealed significant improvements in performance on the BDST difficult trials under 1700lx vs. 165lx (p=0.01), while illuminance level did not affect performance on the PVT and BDST easy trials. Illuminance level impacted HR and SCL, but not SBP. In the afternoon sessions, HR was significantly higher under 1700lx vs. 165lx during PVT performance (p=0.05), while during BDST performance, HR was only slightly higher under 600 vs. 165lx (p=0.06). SCL was significantly higher under 1700lx vs. 165lx during performance on BDST easy trials (p=0.02) and showed similar, but nonsignificant trends during the PVT and BDST difficult trials. Although both physiology and performance were affected by illuminance level, no consistent pattern emerged with respect to parallel changes in physiology and performance. Rather, physiology and performance seemed to be affected independently, via unique pathways. PMID:27221368

  10. Non-image forming effects of illuminance level: Exploring parallel effects on physiological arousal and task performance.

    PubMed

    Huiberts, Laura M; Smolders, Karin C H J; de Kort, Yvonne A W

    2016-10-01

    This study investigated diurnal non-image forming (NIF) effects of illuminance level on physiological arousal in parallel to NIF effects on vigilance and working memory performance. We employed a counterbalanced within-subjects design in which thirty-nine participants (mean age=21.2; SD=2.1; 11 male) completed three 90-min sessions (165 vs. 600lx vs. 1700lx at eye level) either in the morning (N=18) or afternoon (N=21). During each session, participants completed four measurement blocks (incl. one baseline block) each consisting of a 10-min Psychomotor Vigilance Task (PVT) and a Backwards Digit-Span Task (BDST) including easy trials (4-6 digits) and difficult trials (7-8 digits). Heart rate (HR), skin conductance level (SCL) and systolic blood pressure (SBP) were measured continuously. The results revealed significant improvements in performance on the BDST difficult trials under 1700lx vs. 165lx (p=0.01), while illuminance level did not affect performance on the PVT and BDST easy trials. Illuminance level impacted HR and SCL, but not SBP. In the afternoon sessions, HR was significantly higher under 1700lx vs. 165lx during PVT performance (p=0.05), while during BDST performance, HR was only slightly higher under 600 vs. 165lx (p=0.06). SCL was significantly higher under 1700lx vs. 165lx during performance on BDST easy trials (p=0.02) and showed similar, but nonsignificant trends during the PVT and BDST difficult trials. Although both physiology and performance were affected by illuminance level, no consistent pattern emerged with respect to parallel changes in physiology and performance. Rather, physiology and performance seemed to be affected independently, via unique pathways.

  11. Quantum tasks in Minkowski space

    NASA Astrophysics Data System (ADS)

    Kent, Adrian

    2012-11-01

    The fundamental properties of quantum information and its applications to computing and cryptography have been greatly illuminated by considering information-theoretic tasks that are provably possible or impossible within non-relativistic quantum mechanics. I describe here a general framework for defining tasks within (special) relativistic quantum theory and illustrate it with examples from relativistic quantum cryptography and relativistic distributed quantum computation. The framework gives a unified description of all tasks previously considered and also defines a large class of new questions about the properties of quantum information in relation to Minkowski causality. It offers a way of exploring interesting new fundamental tasks and applications, and also highlights the scope for a more systematic understanding of the fundamental information-theoretic properties of relativistic quantum theory.

  12. Annual Progress report - General Task

    SciTech Connect

    Wesnousky, S.G.

    1993-09-30

    This report provides a summary of progress for the project {open_quotes}Evaluation of the Geologic Relations and Seismotectonic Stability of the Yucca Mountain Area, Nevada Nuclear Waste Site Investigation (NNWSI).{close_quotes} A similar report was previously provided for the period of 1 October 1991 to 30 September 1992. The report initially covers the activities of the General Task and is followed by sections that describe the progress of the other ongoing tasks.

  13. Differentiation of rodent behavioral phenotypes and methylphenidate action in sustained and flexible attention tasks.

    PubMed

    Chu, Richard; Shumsky, Jed; Waterhouse, Barry D

    2016-06-15

    Methyphenidate (MPH) is the primary drug treatment of choice for ADHD. It is also frequently used off-label as a cognitive enhancer by otherwise healthy individuals from all age groups and walks of life. Military personnel, students, and health professionals use MPH illicitly to increase attention and improve workplace performance over extended periods of work activity. Despite the frequency of its use, the efficacy of MPH to enhance cognitive function across individuals and in a variety of circumstances is not well characterized. We sought to better understand MPH׳s cognitive enhancing properties in two different rodent models of attention. We found that MPH could enhance performance in a sustained attention task, but that its effects in this test were subject dependent. More specifically, MPH increased attention in low baseline performing rats but had little to no effect on high performing rats. MPH exerted a similar subject specific effect in a test of flexible attention, i.e. the attention set shifting task. In this test MPH increased behavioral flexibility in animals with poor flexibility but impaired performance in more flexible animals. Overall, our results indicate that the effects of MPH are subject-specific and depend on the baseline level of performance. Furthermore, good performance in in the sustained attention task was correlated with good performance in the flexible attention task; i.e. animals with better vigilance exhibited greater behavioral flexibility. The findings are discussed in terms of potential neurobiological substrates, in particular noradrenergic mechanisms, that might underlie subject specific performance and subject specific responses to MPH. This article is part of a Special Issue entitled SI: Noradrenergic System.

  14. Pay attention to impulsivity: modelling low attentive and high impulsive subtypes of adult ADHD in the 5-choice continuous performance task (5C-CPT) in female rats.

    PubMed

    Tomlinson, Anneka; Grayson, Ben; Marsh, Samuel; Harte, Michael K; Barnes, Samuel A; Marshall, Kay M; Neill, Joanna C

    2014-08-01

    Varying levels of attention and impulsivity deficits are core features of the three subtypes of adult attention deficit-hyperactivity disorder (ADHD). To date, little is known about the neurobiological correlates of these subtypes. Development of a translational animal model is essential to improve our understanding and improve therapeutic strategies. The 5-choice continuous performance task (5C-CPT) in rats can be used to examine different forms of attention and impulsivity. Adult rats were trained to pre-set 5C-CPT criterion and subsequently separated into subgroups according to baseline levels of sustained attention, vigilance, premature responding and response disinhibition in the 5C-CPT. The behavioural subgroups were selected to represent the different subtypes of adult ADHD. Consequently, effects of the clinically used pharmacotherapies (methylphenidate and atomoxetine) were assessed in the different subgroups. Four subgroups were identified: low-attentive (LA), high-attentive (HA), high-impulsive (HI) and low-impulsive (LI). Methylphenidate and atomoxetine produced differential effects in the subgroups. Methylphenidate increased sustained attention and vigilance in LA animals, and reduced premature responding in HI animals. Atomoxetine also improved sustained attention and vigilance in LA animals, and reduced response disinhibition and premature responding in HI animals. This is the first study using adult rats to demonstrate the translational value of the 5C-CPT to select subgroups of rats, which may be used to model the subtypes observed in adult ADHD. Our findings suggest that this as an important paradigm to increase our understanding of the neurobiological underpinnings of adult ADHD-subtypes and their response to pharmacotherapy.

  15. The effect of reduced dopamine D4 receptor expression in the 5-choice continuous performance task: Separating response inhibition from premature responding

    PubMed Central

    Young, Jared W.; Powell, Susan B.; Scott, Christine N.; Zhou, Xianjin; Geyer, Mark A.

    2012-01-01

    Impairments in attention/vigilance and response disinhibition are commonly observed in several neuropsychiatric disorders. Validating animal models could help in developing therapeutics for cognitive deficits and improving functional outcomes in such disorders. The 5-choice continuous performance test (5C-CPT) in mice offers the opportunity to assess vigilance and two forms of impulsivity. Since reduced dopamine D4 receptor (DRD4) function is implicated in several disorders, DRD4 is a potential therapeutic target for cognition enhancement. We trained wildtype (WT), heterozygous (HT), and knockout (KO) mice of the murine Drd4 to perform the 5C-CPT under baseline and variable stimulus duration conditions. To dissect motor impulsivity (premature responding) from behavioral disinhibition (false alarms), we administered the 5-HT2C antagonist SB242084 during an extended inter-trial-interval session. We also examined the preattentive and exploratory profile of these mice in prepulse inhibition (PPI) and the Behavioral Pattern Monitor (BPM). Reduced Drd4 expression in HT mice, as confirmed by quantitative RT-PCR, resulted in response dis-inhibition and impaired 5C-CPT performance, while premature responding was unaffected. Conversely, SB242084 increased premature responding without affecting response inhibition or attentional measures. No genotypic differences were observed in PPI or BPM behavior. Thus, reduced Drd4 expression impairs attentional performance, but not other behaviors associated with neuropsychiatric disorders. Moreover, the use of signal and non-signal stimuli in the 5C-CPT enabled the differentiation of response disinhibition from motor impulsivity in a vigilance task. PMID:21458500

  16. Voluntary Task Switching: Chasing the Elusive Homunculus

    ERIC Educational Resources Information Center

    Arrington, Catherine M.; Logan, Gordon D.

    2005-01-01

    In the voluntary task switching procedure, subjects choose the task to perform on a series of bivalent stimuli, requiring top-down control of task switching. Experiments 1-3 contrasted voluntary task switching and explicit task cuing. Choice behavior showed small, inconsistent effects of external stimulus characteristics, supporting the assumption…

  17. Evaluation of the validity of the Psychology Experiment Building Language tests of vigilance, auditory memory, and decision making

    PubMed Central

    Mueller, Shane T.; Talebzadeh, Sara; Ki, Min Jung

    2016-01-01

    Background. The Psychology Experimental Building Language (PEBL) test battery (http://pebl.sourceforge.net/) is a popular application for neurobehavioral investigations. This study evaluated the correspondence between the PEBL and the non-PEBL versions of four executive function tests. Methods. In one cohort, young-adults (N = 44) completed both the Conner’s Continuous Performance Test (CCPT) and the PEBL CPT (PCPT) with the order counter-balanced. In a second cohort, participants (N = 47) completed a non-computerized (Wechsler) and a computerized (PEBL) Digit Span (WDS or PDS) both Forward and Backward. Participants also completed the Psychological Assessment Resources or the PEBL versions of the Iowa Gambling Task (PARIGT or PEBLIGT). Results. The between-test correlations were moderately high (reaction time r = 0.78, omission errors r = 0.65, commission errors r = 0.66) on the CPT. DS Forward was significantly greater than DS Backward on the WDS (p < .0005) and the PDS (p < .0005). The total WDS score was moderately correlated with the PDS (r = 0.56). The PARIGT and the PEBLIGTs showed a very similar pattern for response times across blocks, development of preference for Advantageous over Disadvantageous Decks, and Deck selections. However, the amount of money earned (score–loan) was significantly higher in the PEBLIGT during the last Block. Conclusions. These findings are broadly supportive of the criterion validity of the PEBL measures of sustained attention, short-term memory, and decision making. Select differences between workalike versions of the same test highlight how detailed aspects of implementation may have more important consequences for computerized testing than has been previously acknowledged. PMID:27014512

  18. Evaluation of the validity of the Psychology Experiment Building Language tests of vigilance, auditory memory, and decision making.

    PubMed

    Piper, Brian; Mueller, Shane T; Talebzadeh, Sara; Ki, Min Jung

    2016-01-01

    Background. The Psychology Experimental Building Language (PEBL) test battery (http://pebl.sourceforge.net/) is a popular application for neurobehavioral investigations. This study evaluated the correspondence between the PEBL and the non-PEBL versions of four executive function tests. Methods. In one cohort, young-adults (N = 44) completed both the Conner's Continuous Performance Test (CCPT) and the PEBL CPT (PCPT) with the order counter-balanced. In a second cohort, participants (N = 47) completed a non-computerized (Wechsler) and a computerized (PEBL) Digit Span (WDS or PDS) both Forward and Backward. Participants also completed the Psychological Assessment Resources or the PEBL versions of the Iowa Gambling Task (PARIGT or PEBLIGT). Results. The between-test correlations were moderately high (reaction time r = 0.78, omission errors r = 0.65, commission errors r = 0.66) on the CPT. DS Forward was significantly greater than DS Backward on the WDS (p < .0005) and the PDS (p < .0005). The total WDS score was moderately correlated with the PDS (r = 0.56). The PARIGT and the PEBLIGTs showed a very similar pattern for response times across blocks, development of preference for Advantageous over Disadvantageous Decks, and Deck selections. However, the amount of money earned (score-loan) was significantly higher in the PEBLIGT during the last Block. Conclusions. These findings are broadly supportive of the criterion validity of the PEBL measures of sustained attention, short-term memory, and decision making. Select differences between workalike versions of the same test highlight how detailed aspects of implementation may have more important consequences for computerized testing than has been previously acknowledged. PMID:27014512

  19. Autoimmune disorders after immunisation with Influenza A/H1N1 vaccines with and without adjuvant: EudraVigilance data and literature review.

    PubMed

    Isai, Alina; Durand, Julie; Le Meur, Steven; Hidalgo-Simon, Ana; Kurz, Xavier

    2012-11-19

    All suspected autoimmune disorders (AID) reported as adverse reactions to EudraVigilance from 1 October 2009 to 31 December 2010 for adjuvanted (Celtura™, Fluval P™, Focetria™ and Pandemrix™) and non-adjuvanted (Cantgrip™, Celvapan™ and Panenza™) pandemic Influenza A/H1N1 vaccines were analysed to determine whether adjuvanted vaccines were associated with higher reporting of AID than non-adjuvanted ones. AID were identified based on the corresponding MedDRA High Level Group Term. Reports of type 1 diabetes mellitus and multiple sclerosis were also included in the analysis. Causality was assessed based on WHO causality assessment for adverse events following immunisation and Brighton Collaboration criteria for Guillain-Barré syndrome (GBS), idiopathic thrombocytopenic purpura and acute disseminated encephalomyelitis. Of the 50,221 adverse reactions received in EudraVigilance for A/H1N1 vaccines (adjuvanted: 46,173, non-adjuvanted: 4048), 314 were AID (adjuvanted: 276, non-adjuvanted: 38). GBS was the AID with the highest number of reports (125, adjuvanted: 109, non-adjuvanted: 16). Reporting ratios as calculated by the percentages of AID amongst all reported adverse reactions were 0.60% (95% CI: 0.53-0.67) and 0.94% (95% CI: 0.64-1.24) for adjuvanted and non-adjuvanted vaccines, and were 0.26% (95% CI: 0.22-0.31) and 0.37% (95% CI: 0.18-0.56) in a restricted analysis based on diagnostic certainty, causal relationship and plausible temporal association. Reporting rates for all reports of AID using the estimated number of vaccinees as denominator were 6.87 (95% CI: 6.06-7.68) and 9.98 (95% CI: 6.81-13.16) per million for adjuvanted and non-adjuvanted vaccines, and 3.01 (95% CI: 2.47-3.55) and 3.94 (95% CI: 1.95-5.94) per million in the restricted analysis. These results do not suggest a difference in the reporting of AID between adjuvanted and non-adjuvanted A/H1N1 vaccines. In a literature review performed on 31 August 2011, GBS was also the AID the

  20. Performance Effects of Display Incogruity in a Digital and Analog Clock Reading Task

    NASA Technical Reports Server (NTRS)

    Comstock, J. Raymond, Jr.; Derks, Peter L.

    2004-01-01

    In an era of increasing automation, it is important to design displays and input devices that minimize human error. In this context, information concerning the human response to the detection of incongruous information is important. Such incongruous information can be operationalized as unexpected (perhaps erroneous) information on which a decision by the human or operation by an automated system is based. In the aviation environment, decision making when faced with inadequate, incomplete, or incongruous information may occur in a failure scenario. An additional challenge facing the human operator in automated environments is maintaining alertness or vigilance. The vigilance issue is of particular concern as a factor that may interact with performance when faced with inadequate, incomplete, or incongruous information. From the literature on eye-scan behavior we know that the time spent looking at a particular display or indicator is a function of the type of information one is trying to discern from the display. For example, quick glances are all it takes for confirming that an indicator is in a normal position or range, whereas a continuous look of several seconds may be required for confirmation that a complex control input is having the desired effect. Important to consider is that while an extended look takes place, visual input from other sources may be missed. Much like an extended look, the interpretation of incongruous information may require extra time. The present experiment was designed to explore the performance consequences of a decision making task when incongruous information was presented. For this experiment a display incongruity was created on a subset of trials of a clock reading laboratory task. Display incongruity was made possible through presentation of 'impossible' times (e.g. 1:65 or 11:90). Subjects made 'same' 'different' decisions and keyboard responses to pairings of Analog-Analog (AA), Digital-Digital (DD), and Analog- Digital (AD

  1. Authentic Tasks Online: A Synergy among Learner, Task, and Technology

    ERIC Educational Resources Information Center

    Herrington, Jan; Reeves, Thomas C.; Oliver, Ron

    2006-01-01

    Fostering synergies amongst "learner," "task," and "technology" to create innovative and immersive distance learning environments runs counter to the widespread practice of incorporating traditional classroom pedagogical strategies into Web-based delivery of courses. The most widely accepted model of online higher education appears to be one of…

  2. Task Lists for Industrial Occupations. Education for Employment Task Lists.

    ERIC Educational Resources Information Center

    Dimmlich, David

    These cluster matrices provide duties and tasks that form the basis of instructional content for secondary, postsecondary, and adult occupational training programs for industrial occupations. Duties and skills are presented for the following: (1) electric home appliance and power tool repairers; (2) office machine/cash register repairer; (3)…

  3. Fractals, Vigilance, and Adolescent Diabetes Management: A Case for When Regulation May Be Difficult to Measure With the Current Medical Standards.

    PubMed

    Butner, Jonathan; Story, T Nathan; Berg, Cynthia A; Wiebe, Deborah J

    2011-02-01

    Temporal patterning in blood glucose (BG) consistent with fractals-how BG follows a repetitive pattern through resolutions of time-was used to examine 2 different samples of adolescents with Type 1 diabetes (10-14 years). Sample 1 contained 10 adolescents with longtime series for accurate estimations of long-term dependencies associated with fractals. The second contained 94 adolescents measured multiple times daily over a 2-week period corresponding to psychosocial measures. In both samples, temporal dependencies in BG showed patterns consistent with fractals. In the second sample, temporal dependencies were associated with indicators of vigilant regulation including adolescents' higher anxiety, mothers' higher monitoring, and intrusive support. The existence of temporal dependencies in BG moderated the relationship between glycosylated hemoglobin (HbA1c) and indicators of low BG risk but not the relationship between HbA1c and high BG risk. These results show how a biomedical indicator may be susceptible to metric issues associated with fractals.

  4. Vigilance against predators induced by eavesdropping on heterospecific alarm calls in a non-vocal lizard Oplurus cuvieri cuvieri (Reptilia: Iguania).

    PubMed

    Ito, Ryo; Mori, Akira

    2010-04-22

    Prey animals can reduce their risk of predation by detecting potential predators before encounters occur. Some animals gain information about nearby predators by eavesdropping on heterospecific alarm calls. Despite having well-developed ears, most lizards do not use vocal information for intraspecific communication, and few studies have shown practical use of the ears in wild lizards. Here, we show that the Madagascan spiny-tailed iguana (Oplurus cuvieri cuvieri) obtains auditory signals for predator detection. The Madagascan spiny-tailed iguana and the Madagascar paradise flycatcher (Terpsiphone mutata) are syntopic inhabitants of the Ampijoroa dry deciduous forest of Madagascar. The iguana and the flycatcher have neither a predator-prey relationship nor resource competition, but they have shared predators such as raptors and snakes. Using playback experiments, we demonstrated that the iguana discriminates mobbing alarm calls of the flycatcher from its songs and then enhances its vigilance behaviour. Our results demonstrate the occurrence of an asymmetrical ecological relationship between the Madagascan spiny-tailed iguana and the paradise flycatcher through eavesdropping on information about the presence of predators. This implies that indirect interspecific interactions through information recognition may be more common than generally thought in an animal community.

  5. Working Memory, Task Switching, and Executive Control in the Task Span Procedure

    ERIC Educational Resources Information Center

    Logan, Gordon D.

    2004-01-01

    Four experiments explored the task span procedure: Subjects received lists of 1-10 task names to remember and then lists of 1-10 stimuli on which to perform the tasks. Task span is the number of tasks performed in order perfectly. Experiment 1 compared the task span with the traditional memory span in 6 practiced subjects and found little…

  6. A synthesized heuristic task scheduling algorithm.

    PubMed

    Dai, Yanyan; Zhang, Xiangli

    2014-01-01

    Aiming at the static task scheduling problems in heterogeneous environment, a heuristic task scheduling algorithm named HCPPEFT is proposed. In task prioritizing phase, there are three levels of priority in the algorithm to choose task. First, the critical tasks have the highest priority, secondly the tasks with longer path to exit task will be selected, and then algorithm will choose tasks with less predecessors to schedule. In resource selection phase, the algorithm is selected task duplication to reduce the interresource communication cost, besides forecasting the impact of an assignment for all children of the current task permits better decisions to be made in selecting resources. The algorithm proposed is compared with STDH, PEFT, and HEFT algorithms through randomly generated graphs and sets of task graphs. The experimental results show that the new algorithm can achieve better scheduling performance.

  7. The Dissipating Task-Repetition Benefit in Cued Task Switching: Task-Set Decay or Temporal Distinctiveness?

    ERIC Educational Resources Information Center

    Horoufchin, Himeh; Philipp, Andrea M.; Koch, Iring

    2011-01-01

    Decay of task-set activation, as commonly assumed in models of task switching, has been thought to be indexed by manipulating the response-to-cue interval (RCI) in a task-cuing paradigm. We propose an alternative account for RCI effects suggesting that episodic task retrieval is modulated by temporal distinctiveness, which we define as the ratio…

  8. Operational assessment of the 5-h on/10-h off watchstanding schedule on a US Navy ship: sleep patterns, mood and psychomotor vigilance performance of crewmembers in the nuclear reactor department.

    PubMed

    Shattuck, Nita Lewis; Matsangas, Panagiotis

    2016-05-01

    We assessed sleep patterns, psychomotor vigilance performance, work demands and mood of 77 crewmembers of USS NIMITZ (CVN-68) on the rotating 5-h on/10-h off (5/10) watchstanding schedule. Within the 3-day cycle of the 5/10, sleep occurred at distinctly different times each day. On two of these days, sailors typically received only brief, 4-h sleep episodes followed by periods of sustained wakefulness (approximately 22 and 20 h). Crewmembers received approximately seven hours of sleep daily, but reported excessive fatigue and dissatisfaction with their schedule. Crewmembers' mood worsened significantly over the course of the underway phase. Psychomotor vigilance performance (reaction times, lapses) was significantly degraded compared to performance when working circadian-aligned schedules. Overall, standing watch on the 5/10 schedule, combined with other work duties, resulted in poor sleep hygiene. Crewmembers on the 5/10 experienced periodic bouts of sustained wakefulness and accrued a significant sleep debt due to extended workdays and circadian-misaligned sleep. Practitioner summary: We assessed crewmembers' sleep patterns, psychomotor vigilance performance and work demands when working a rotating 5-h on/10-h off (5/10) watchstanding schedule. The 5/10, combined with other work duties, resulted in poor sleep hygiene. Crewmembers experienced periodic bouts of sustained wakefulness and accrued a significant sleep debt due to extended workdays and circadian-misaligned sleep.

  9. Operational assessment of the 5-h on/10-h off watchstanding schedule on a US Navy ship: sleep patterns, mood and psychomotor vigilance performance of crewmembers in the nuclear reactor department.

    PubMed

    Shattuck, Nita Lewis; Matsangas, Panagiotis

    2016-05-01

    We assessed sleep patterns, psychomotor vigilance performance, work demands and mood of 77 crewmembers of USS NIMITZ (CVN-68) on the rotating 5-h on/10-h off (5/10) watchstanding schedule. Within the 3-day cycle of the 5/10, sleep occurred at distinctly different times each day. On two of these days, sailors typically received only brief, 4-h sleep episodes followed by periods of sustained wakefulness (approximately 22 and 20 h). Crewmembers received approximately seven hours of sleep daily, but reported excessive fatigue and dissatisfaction with their schedule. Crewmembers' mood worsened significantly over the course of the underway phase. Psychomotor vigilance performance (reaction times, lapses) was significantly degraded compared to performance when working circadian-aligned schedules. Overall, standing watch on the 5/10 schedule, combined with other work duties, resulted in poor sleep hygiene. Crewmembers on the 5/10 experienced periodic bouts of sustained wakefulness and accrued a significant sleep debt due to extended workdays and circadian-misaligned sleep. Practitioner summary: We assessed crewmembers' sleep patterns, psychomotor vigilance performance and work demands when working a rotating 5-h on/10-h off (5/10) watchstanding schedule. The 5/10, combined with other work duties, resulted in poor sleep hygiene. Crewmembers experienced periodic bouts of sustained wakefulness and accrued a significant sleep debt due to extended workdays and circadian-misaligned sleep. PMID:26360772

  10. Task-Based Writing Instruction

    ERIC Educational Resources Information Center

    Bantis, Alexandros

    2010-01-01

    The purpose of this study was to investigate the impact of task-based writing instruction, a communicative language-teaching method, on second language acquisition and differentiation of instruction for English language learners during the independent work time instructional component of the Open Court Reading program. Through student-teacher…

  11. Dimensions of Organizational Task Environments.

    ERIC Educational Resources Information Center

    Dess, Gregory G.; Beard, Donald W.

    1984-01-01

    Reducing Aldrich's codification of organizational task environments from six to three dimensions--munificence (capacity), complexity (homogeneity-heterogeneity, concentration-dispersion), and dynamism (stability-instability, turbulence), the authors use interim and factor analytical techniques to explore each dimension's viability and draw…

  12. American Indian Task Force Report.

    ERIC Educational Resources Information Center

    Mackey, John E., Ed.

    Assuming that the client is central to any service program, the American Indian Task Force examined a national sample of "grass roots" social service organizations and/or individuals and schools of social work to determine the capability of providing relevant social work education to American Indians. Accordingly, the highest priorities…

  13. Tasks Ahead for Indian Education.

    ERIC Educational Resources Information Center

    Yadav, R. K.

    1980-01-01

    Reviews past accomplishments and remaining tasks in Indian education with particular emphasis on the production of technical and professional personnel to match the nation's labor needs and the spread of education to three previously disadvantaged groups: rural populations, women, and the scheduled castes and tribes. (SJL)

  14. Incidental Learning and Task Boundaries

    ERIC Educational Resources Information Center

    Freedberg, Michael; Wagschal, Tana T.; Hazeltine, Eliot

    2014-01-01

    For skill learning processes to be effective, they must encode associations that are inherent to the current task and avoid those that are spurious or particular to training conditions so that learning can transfer to novel situations. Some everyday contexts even require grouped responding to simultaneously presented stimuli. Here we test whether…

  15. Task-driven dictionary learning.

    PubMed

    Mairal, Julien; Bach, Francis; Ponce, Jean

    2012-04-01

    Modeling data with linear combinations of a few elements from a learned dictionary has been the focus of much recent research in machine learning, neuroscience, and signal processing. For signals such as natural images that admit such sparse representations, it is now well established that these models are well suited to restoration tasks. In this context, learning the dictionary amounts to solving a large-scale matrix factorization problem, which can be done efficiently with classical optimization tools. The same approach has also been used for learning features from data for other purposes, e.g., image classification, but tuning the dictionary in a supervised way for these tasks has proven to be more difficult. In this paper, we present a general formulation for supervised dictionary learning adapted to a wide variety of tasks, and present an efficient algorithm for solving the corresponding optimization problem. Experiments on handwritten digit classification, digital art identification, nonlinear inverse image problems, and compressed sensing demonstrate that our approach is effective in large-scale settings, and is well suited to supervised and semi-supervised classification, as well as regression tasks for data that admit sparse representations. PMID:21808090

  16. Task Group 9 Update (Presentation)

    SciTech Connect

    Bosco, N.

    2014-04-01

    This presentation is a brief update of IEC TC82 QA Task Force, Group 9. Presented is an outline of the recently submitted New Work Item Proposal (NWIP) for a Comparative Thermal Cycling Test for CPV Modules to Differentiate Thermal Fatigue Durability.

  17. A Population of Assessment Tasks

    ERIC Educational Resources Information Center

    Daro, Phil; Burkhardt, Hugh

    2012-01-01

    We propose the development of a "population" of high-quality assessment tasks that cover the performance goals set out in the "Common Core State Standards for Mathematics." The population will be published. Tests are drawn from this population as a structured random sample guided by a "balancing algorithm."

  18. Inhibition in Prolonged Work Tasks.

    ERIC Educational Resources Information Center

    van der Ven, A. H. G. S.; And Others

    1989-01-01

    A new model is presented that explains reaction time fluctuations in prolonged work tasks. The model extends the so-called Poisson-Erlang model and accounts for long-term trend effects in the reaction time curve. The model is consistent with Spearman's hypothesis that inhibition increases during work and decreases during rest. (TJH)

  19. TASK ANALYSIS AND TRAINING DESIGN.

    ERIC Educational Resources Information Center

    ANNETT, J.; DUNCAN, K.D.

    PERHAPS THE MAJOR PROBLEM IN TASK ANALYSIS FOR INDUSTRIAL TRAINING IS TO DETERMINE WHAT TO DESCRIBE AND ON WHAT LEVEL OF DETAIL. MANY DIFFERENT LEVELS OF DESCRIPTION MAY BE NEEDED TO ESTIMATE THE COST OF INADEQUATE PERFORMANCE TO A SYSTEM AND THE PROBABILITY OF ADEQUATE PERFORMANCE WITHOUT TRAINING--THE PROBLEM OF IDENTIFYING DIFFICULT COMPONENTS…

  20. Supporting Task-Focused Communication.

    ERIC Educational Resources Information Center

    Lipinski, Hubert; And Others

    The extension of computer based communication to the more task-focused communication required by groups involved in joint problem solving is discussed in this paper. Specifically, it addresses three areas: (1) the aspects of the joint problem solving that are most suited to computer based communication support, (2) the computer based communication…

  1. Task Analysis Inventories. Series II.

    ERIC Educational Resources Information Center

    Wesson, Carl E.

    This second in a series of task analysis inventories contains checklists of work performed in twenty-two occupations. Each inventory is a comprehensive list of work activities, responsibilities, educational courses, machines, tools, equipment, and work aids used and the products produced or services rendered in a designated occupational area. The…

  2. Upper Secondary Students' Task Reasoning

    ERIC Educational Resources Information Center

    Bergqvist, T.; Lithner, J.; Sumpter, L.

    2008-01-01

    Upper secondary students' task solving reasoning was analysed, with a focus on grounds for different strategy choices and implementations. The results indicate that mathematically well-founded considerations were rare. The dominating reasoning types were algorithmic reasoning, where students tried to remember a suitable algorithm, sometimes in a…

  3. Cosmetology: Task Analyses. Competency-Based Education.

    ERIC Educational Resources Information Center

    Henrico County Public Schools, Glen Allen, VA. Virginia Vocational Curriculum Center.

    These task analyses are designed to be used in combination with the "Trade and Industrial Education Service Area Resource" in order to implement competency-based education in the cosmetology program in Virginia. The task analysis document contains the task inventory, suggested task sequence lists, and content outlines for the secondary courses…

  4. An architecture for intelligent task interruption

    NASA Technical Reports Server (NTRS)

    Sharma, D. D.; Narayan, Srini

    1990-01-01

    In the design of real time systems the capability for task interruption is often considered essential. The problem of task interruption in knowledge-based domains is examined. It is proposed that task interruption can be often avoided by using appropriate functional architectures and knowledge engineering principles. Situations for which task interruption is indispensable, a preliminary architecture based on priority hierarchies is described.

  5. Tasks for Easily Modifiable Virtual Environments

    ERIC Educational Resources Information Center

    Swier, Robert

    2014-01-01

    Recent studies of learner interaction in virtual worlds have tended to select basic tasks involving open-ended communication. There is evidence that such tasks are supportive of language acquisition, however it may also be beneficial to consider more complex tasks. Research in task-based learning has identified features such as non-linguistic…

  6. PRESCHOOL CHILDREN'S WILLINGNESS TO TRY DIFFICULT TASKS.

    ERIC Educational Resources Information Center

    STARKWEATHER, ELIZABETH K.

    INSTRUMENTS WERE ADMINISTERED TO PRESCHOOL CHILDREN TO MEASURE THEIR PERFORMANCE ON VARIOUS TASKS. THE INSTRUMENTS WERE (1) A BUTTONING TASK FOR FINE MOTOR COORDINATION, (2) A PUZZLE TASK FOR VISUAL DISCRIMINATION, AND (3) A TARGET GAME FOR GROSS MOTOR COORDINATION. EACH INSTRUMENT CONSISTED OF FIVE TASKS GRADED IN DIFFICULTY, ADJUSTED TO THE…

  7. Serpentine Robots for Inspection Tasks

    SciTech Connect

    Choset, Howie

    2003-09-11

    Serpentine robots are snake like devices that can use their internal degrees of freedom to thread through tightly packed volumes accessing locations that people or conventional machinery cannot. These devices are ideally suited for minimally invasive inspection tasks where the surrounding areas do not have to be disturbed. Applications for these devices are therefore inspection of underground tanks and other storage facilities for classification purposes. This work deals with the design, construction, and control of a serpentine robot. The challenges lie in developing a device that can lift itself in three dimensions, which is necessary for the inspection tasks. The other challenge in control deals with coordinating all of the internal degrees of freedom to exact purposeful motion.

  8. Task-oriented situation recognition

    NASA Astrophysics Data System (ADS)

    Bauer, Alexander; Fischer, Yvonne

    2010-04-01

    From the advances in computer vision methods for the detection, tracking and recognition of objects in video streams, new opportunities for video surveillance arise: In the future, automated video surveillance systems will be able to detect critical situations early enough to enable an operator to take preventive actions, instead of using video material merely for forensic investigations. However, problems such as limited computational resources, privacy regulations and a constant change in potential threads have to be addressed by a practical automated video surveillance system. In this paper, we show how these problems can be addressed using a task-oriented approach. The system architecture of the task-oriented video surveillance system NEST and an algorithm for the detection of abnormal behavior as part of the system are presented and illustrated for the surveillance of guests inside a video-monitored building.

  9. Fuel oil quality task force

    SciTech Connect

    Laisy, J.; Turk, V.

    1997-09-01

    In April, 1996, the R.W. Beckett Corporation became aware of a series of apparently unrelated symptoms that made the leadership of the company concerned that there could be a fuel oil quality problem. A task force of company employees and industry consultants was convened to address the topic of current No. 2 heating oil quality and its effect on burner performance. The task force studied changes in fuel oil specifications and trends in properties that have occurred over the past few years. Experiments were performed at Beckett and Brookhaven National Laboratory to understand the effect of changes in some fuel oil properties. Studies by other groups were reviewed, and field installations were inspected to gain information about the performance of fuel oil that is currently being used in the U.S. and Canada. There was a special concern about the use of red dye in heating oils and the impact of sulfur levels due to the October, 1993 requirement of low sulfur (<0.05%) for on-highway diesel fuel. The results of the task force`s efforts were published in July, 1996. The primary conclusion of the task force was that there is not a crisis or widespread general problem with fuel oil quality. Localized problems that were seen may have been related to refinery practices and/or non-traditional fuel sources. System cleanliness is very important and the cause of many oil burner system problems. Finally, heating oil quality should get ongoing careful attention by Beckett engineering personnel and heating oil industry groups.

  10. Updating Sensory "versus" Task Representations during Task-Switching: Insights from Cognitive Brain Potentials in Humans

    ERIC Educational Resources Information Center

    Perianez, Jose A.; Barcelo, Francisco

    2009-01-01

    Task-cueing studies suggest that the updating of sensory and task representations both contribute to behavioral task-switch costs [Forstmann, B. U., Brass, M., & Koch, I. (2007). "Methodological and empirical issues when dissociating cue-related from task-related processes in the explicit task-cuing procedure." "Psychological Research, 71"(4),…

  11. Learner-Learner Interaction during Collaborative Pragmatic Tasks: The Role of Cognitive and Pragmatic Task Demands

    ERIC Educational Resources Information Center

    Kim, YouJin; Taguchi, Naoko

    2016-01-01

    Previous task complexity studies have suggested that learners produce more negotiation of meaning opportunities during complex tasks than simple tasks (Robinson, 2011). The present study builds on the existing task complexity literature by examining the impact of task complexity and pragmatic situational demands on the number of learning…

  12. Investigating Perfect Timesharing: The Relationship between IM-Compatible Tasks and Dual-Task Performance

    ERIC Educational Resources Information Center

    Halvorson, Kimberly M.; Ebner, Herschel; Hazeltine, Eliot

    2013-01-01

    Why are dual-task costs reduced with ideomotor (IM) compatible tasks (Greenwald & Shulman, 1973; Lien, Proctor & Allen, 2002)? In the present experiments, we first examine three different measures of single-task performance (pure single-task blocks, mixed blocks, and long stimulus onset asynchrony [SOA] trials in dual-task blocks) and two measures…

  13. The Shielding Function of Task Sets and Its Relaxation during Task Switching

    ERIC Educational Resources Information Center

    Dreisbach, Gesine; Wenke, Dorit

    2011-01-01

    The goal of the presented experiments was to investigate the dynamic interplay of task shielding and its relaxation during task switching. Task shielding refers to the finding that single task sets in terms of 2-choice categorization rules help shielding against distraction from irrelevant stimulus attributes. During task switching, this shielding…

  14. Task appraisals, emotions, and performance goal orientation.

    PubMed

    Fisher, Cynthia D; Minbashian, Amirali; Beckmann, Nadin; Wood, Robert E

    2013-03-01

    We predict real-time fluctuations in employees' positive and negative emotions from concurrent appraisals of the immediate task situation and individual differences in performance goal orientation. Task confidence, task importance, positive emotions, and negative emotions were assessed 5 times per day for 3 weeks in an experience sampling study of 135 managers. At the within-person level, appraisals of task confidence, task importance, and their interaction predicted momentary positive and negative emotions as hypothesized. Dispositional performance goal orientation was expected to moderate emotional reactivity to appraisals of task confidence and task importance. The hypothesized relationships were significant in the case of appraisals of task importance. Those high on performance goal orientation reacted to appraisals of task importance with stronger negative and weaker positive emotions than those low on performance goal orientation. PMID:23276116

  15. Attention in a multi-task environment

    NASA Technical Reports Server (NTRS)

    Andre, Anthony D.; Heers, Susan T.

    1993-01-01

    Two experiments used a low fidelity multi-task simulation to investigate the effects of cue specificity on task preparation and performance. Subjects performed a continuous compensatory tracking task and were periodically prompted to perform one of several concurrent secondary tasks. The results provide strong evidence that subjects enacted a strategy to actively divert resources towards secondary task preparation only when they had specific information about an upcoming task to be performed. However, this strategy was not as much affected by the type of task cued (Experiment 1) or its difficulty level (Experiment 2). Overall, subjects seemed aware of both the costs (degraded primary task tracking) and benefits (improved secondary task performance) of cue information. Implications of the present results for computational human performance/workload models are discussed.

  16. The effects of stimulus modality and task integrality: Predicting dual-task performance and workload from single-task levels

    NASA Technical Reports Server (NTRS)

    Hart, S. G.; Shively, R. J.; Vidulich, M. A.; Miller, R. C.

    1986-01-01

    The influence of stimulus modality and task difficulty on workload and performance was investigated. The goal was to quantify the cost (in terms of response time and experienced workload) incurred when essentially serial task components shared common elements (e.g., the response to one initiated the other) which could be accomplished in parallel. The experimental tasks were based on the Fittsberg paradigm; the solution to a SternBERG-type memory task determines which of two identical FITTS targets are acquired. Previous research suggested that such functionally integrated dual tasks are performed with substantially less workload and faster response times than would be predicted by suming single-task components when both are presented in the same stimulus modality (visual). The physical integration of task elements was varied (although their functional relationship remained the same) to determine whether dual-task facilitation would persist if task components were presented in different sensory modalities. Again, it was found that the cost of performing the two-stage task was considerably less than the sum of component single-task levels when both were presented visually. Less facilitation was found when task elements were presented in different sensory modalities. These results suggest the importance of distinguishing between concurrent tasks that complete for limited resources from those that beneficially share common resources when selecting the stimulus modalities for information displays.

  17. 80 FR 27688 - Make-Up Meetings of the Community Preventive Services Task Force (Task Force)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2015-05-14

    ... of systematic reviews on existing research, and issues recommendations. Task Force recommendations... jurisdictions and constituents. The Task Force's recommendations, along with the systematic reviews of the... Force to consider the findings of systematic reviews and issue findings and recommendations. Task...

  18. The BOLD Response during Stroop Task-Like Inhibition Paradigms: Effects of Task Difficulty and Task-Relevant Modality

    ERIC Educational Resources Information Center

    Mitchell, Rachel L. C.

    2005-01-01

    Previous studies of the Stroop task propose two key mediators: the prefrontal and cingulate cortices but hints exist of functional specialization within these regions. This study aimed to examine the effect of task modality upon the prefrontal and cingulate response by examining the response to colour, number, and shape Stroop tasks whilst BOLD…

  19. Task variation versus task repetition for people with profound developmental disabilities: an assessment of preferences.

    PubMed

    Lancioni, G E; O'Reilly, M F; Campodonico, F; Mantini, M

    1998-01-01

    An assessment of preferences between task variation and task repetition with four adults with profound developmental disabilities was implemented. After participants were exposed to both task variation and task repetition conditions, they were allowed to choose between them. Results showed that all participants had strong preferences; three preferred task variation and one task repetition. Aspects of the assessment and use of assessment data for planning daily work conditions were discussed.

  20. Antenna pattern study, task 2

    NASA Technical Reports Server (NTRS)

    Harper, Warren

    1989-01-01

    Two electromagnetic scattering codes, NEC-BSC and ESP3, were delivered and installed on a NASA VAX computer for use by Marshall Space Flight Center antenna design personnel. The existing codes and certain supplementary software were updated, the codes installed on a computer that will be delivered to the customer, to provide capability for graphic display of the data to be computed by the use of the codes and to assist the customer in the solution of specific problems that demonstrate the use of the codes. With the exception of one code revision, all of these tasks were performed.

  1. General Aviation Task Force report

    NASA Technical Reports Server (NTRS)

    1993-01-01

    General aviation is officially defined as all aviation except scheduled airlines and the military. It is the only air transportation to many communities throughout the world. In order to reverse the recent decline in general aviation aircraft produced in the United States, the Task Force recommends that NASA provide the expertise and facilities such as wind tunnels and computer codes for aircraft design. General aviation manufacturers are receptive to NASA's innovations and technological leadership and are expected to be effective users of NASA-generated technologies.

  2. A higher illuminance induces alertness even during office hours: findings on subjective measures, task performance and heart rate measures.

    PubMed

    Smolders, K C H J; de Kort, Y A W; Cluitmans, P J M

    2012-08-20

    Nocturnal white light exposure has shown marked results on subjective and objective indicators of alertness, vitality and mood, yet effects of white light during daytime and under usual office work conditions have not been investigated extensively. The current study employed a mixed-group design (N=32), testing effects of two illuminance levels (200lx or 1000lx at eye level, 4000K) during one hour of morning versus afternoon exposure. In four repeated blocks, subjective reports, objective performance and physiological arousal were measured. Results showed effects of illuminance on subjective alertness and vitality, sustained attention in tasks, and heart rate and heart rate variability. Participants felt less sleepy and more energetic in the high versus the low lighting condition, had shorter reaction times on the psychomotor vigilance task and increased physiological arousal. Effects of illuminance on the subjective measures, as well as those on heart rate were not dependent on time of day or duration of exposure. Performance effects were most pronounced in the morning sessions and towards the end of the one-hour exposure period. The effect on heart rate variability was also most pronounced at the end of the one-hour exposure. The results demonstrate that even under normal, i.e., neither sleep nor light deprived conditions, more intense light can improve feelings of alertness and vitality, as well as objective performance and physiological arousal.

  3. A higher illuminance induces alertness even during office hours: findings on subjective measures, task performance and heart rate measures.

    PubMed

    Smolders, K C H J; de Kort, Y A W; Cluitmans, P J M

    2012-08-20

    Nocturnal white light exposure has shown marked results on subjective and objective indicators of alertness, vitality and mood, yet effects of white light during daytime and under usual office work conditions have not been investigated extensively. The current study employed a mixed-group design (N=32), testing effects of two illuminance levels (200lx or 1000lx at eye level, 4000K) during one hour of morning versus afternoon exposure. In four repeated blocks, subjective reports, objective performance and physiological arousal were measured. Results showed effects of illuminance on subjective alertness and vitality, sustained attention in tasks, and heart rate and heart rate variability. Participants felt less sleepy and more energetic in the high versus the low lighting condition, had shorter reaction times on the psychomotor vigilance task and increased physiological arousal. Effects of illuminance on the subjective measures, as well as those on heart rate were not dependent on time of day or duration of exposure. Performance effects were most pronounced in the morning sessions and towards the end of the one-hour exposure period. The effect on heart rate variability was also most pronounced at the end of the one-hour exposure. The results demonstrate that even under normal, i.e., neither sleep nor light deprived conditions, more intense light can improve feelings of alertness and vitality, as well as objective performance and physiological arousal. PMID:22564492

  4. U.S. Preventive Services Task Force

    MedlinePlus

    ... USPSTF Our Members Conflict of Interest Disclosures Task Force 101 Resources Our Partners Reports to Congress Contact ... effort to make the U.S. Preventive Services Task Force (USPSTF) recommendations clearer and its processes more transparent, ...

  5. Fault-tolerant dynamic task graph scheduling

    SciTech Connect

    Kurt, Mehmet C.; Krishnamoorthy, Sriram; Agrawal, Kunal; Agrawal, Gagan

    2014-11-16

    In this paper, we present an approach to fault tolerant execution of dynamic task graphs scheduled using work stealing. In particular, we focus on selective and localized recovery of tasks in the presence of soft faults. We elicit from the user the basic task graph structure in terms of successor and predecessor relationships. The work stealing-based algorithm to schedule such a task graph is augmented to enable recovery when the data and meta-data associated with a task get corrupted. We use this redundancy, and the knowledge of the task graph structure, to selectively recover from faults with low space and time overheads. We show that the fault tolerant design retains the essential properties of the underlying work stealing-based task scheduling algorithm, and that the fault tolerant execution is asymptotically optimal when task re-execution is taken into account. Experimental evaluation demonstrates the low cost of recovery under various fault scenarios.

  6. Emotional task management: neural correlates of switching between affective and non-affective task-sets

    PubMed Central

    Reeck, Crystal

    2015-01-01

    Although task-switching has been investigated extensively, its interaction with emotionally salient task content remains unclear. Prioritized processing of affective stimulus content may enhance accessibility of affective task-sets and generate increased interference when switching between affective and non-affective task-sets. Previous research has demonstrated that more dominant task-sets experience greater switch costs, as they necessitate active inhibition during performance of less entrenched tasks. Extending this logic to the affective domain, the present experiment examined (a) whether affective task-sets are more dominant than non-affective ones, and (b) what neural mechanisms regulate affective task-sets, so that weaker, non-affective task-sets can be executed. While undergoing functional magnetic resonance imaging, participants categorized face stimuli according to either their gender (non-affective task) or their emotional expression (affective task). Behavioral results were consistent with the affective task dominance hypothesis: participants were slower to switch to the affective task, and cross-task interference was strongest when participants tried to switch from the affective to the non-affective task. These behavioral costs of controlling the affective task-set were mirrored in the activation of a right-lateralized frontostriatal network previously implicated in task-set updating and response inhibition. Connectivity between amygdala and right ventrolateral prefrontal cortex was especially pronounced during cross-task interference from affective features. PMID:25552571

  7. Be Vigilant on Financial Statements.

    ERIC Educational Resources Information Center

    Freed, DeBow

    2002-01-01

    Highlights areas on university's financial statements that warrant careful review by trustees and suggests ways they can check to see whether an institution's financial statements are clear and valid indicators of its financial status. (EV)

  8. Academic Freedom Requires Constant Vigilance

    ERIC Educational Resources Information Center

    Emery, Kim

    2009-01-01

    Traditionally, academic freedom has been understood as an individual right and a negative liberty. As William Tierney and Vincente Lechuga explain, "Academic freedom, although an institutional concept, was vested in the individual professor." The touchstone document on academic freedom, the American Association of University Professor's (AAUP)…

  9. Managing Multiple Tasks in Complex, Dynamic Environments

    NASA Technical Reports Server (NTRS)

    Freed, Michael; Null, Cynthia H. (Technical Monitor)

    1998-01-01

    Sketchy planners are designed to achieve goals in realistically complex, time-pressured, and uncertain task environments. However, the ability to manage multiple, potentially interacting tasks in such environments requires extensions to the functionality these systems typically provide. This paper identifies a number of factors affecting how interacting tasks should be prioritized, interrupted, and resumed, and then describes a sketchy planner called APEX that takes account of these factors when managing multiple tasks.

  10. An overview of task order 10

    SciTech Connect

    Rousculp, Christopher L

    2011-01-12

    Task Order 10 formalizes a collaboration in high explosive pulsed power (HEPP) experiments between LANL and VNIIEF. The focus is the VNIIEF disk explosive magnetic generator (DEMG) technology. The task order outlines a sequence of tasks and deliverables culminating in an experiment which takes place in the US utilizing US explosives and a Russian DEMG. This talk summarizes task order 10. It gives a brief history and present status in terms of the proposed high pressure EOS experiment (ALT-3).

  11. Environmental heat stress enhances mental fatigue during sustained attention task performing: evidence from an ASL perfusion study.

    PubMed

    Qian, Shaowen; Li, Min; Li, Guoying; Liu, Kai; Li, Bo; Jiang, Qingjun; Li, Li; Yang, Zhen; Sun, Gang

    2015-03-01

    This study was to investigate the potential enhancing effect of heat stress on mental fatigue progression during sustained attention task using arterial spin labeling (ASL) imaging. Twenty participants underwent two thermal exposures in an environmental chamber: normothermic (NT) condition (25°C, 1h) and hyperthermic (HT) condition (50°C, 1h). After thermal exposure, they performed a twenty-minute psychomotor vigilance test (PVT) in the scanner. Behavioral analysis revealed progressively increasing subjective fatigue ratings and reaction time as PVT progressed. Moreover, heat stress caused worse performance. Perfusion imaging analyses showed significant resting-state cerebral blood flow (CBF) alterations after heat exposure. Specifically, increased CBF mainly gathered in thalamic-brainstem area while decreased CBF predominantly located in fronto-parietal areas, anterior cingulate cortex, posterior cingulate cortex, and medial frontal cortex. More importantly, diverse CBF distributions and trend of changes between both conditions were observed as the fatigue level progressed during subsequent PVT task. Specifically, higher CBF and enhanced rising trend were presented in superior parietal lobe, precuneus, posterior cingulate cortex and anterior cingulate cortex, while lower CBF or inhibited rising trend was found in dorsolateral frontal cortex, medial frontal cortex, inferior parietal lobe and thalamic-brainstem areas. Furthermore, the decrease of post-heat resting-state CBF in fronto-parietal cortex was correlated with subsequent slower reaction time, suggesting prior disturbed resting-state CBF might be indicator of performance potential and fatigue level in following task. These findings may provide proof for such a view: heat stress has a potential fatigue-enhancing effect when individual is performing highly cognition-demanding attention task.

  12. Task Variables in Mathematical Problem Solving.

    ERIC Educational Resources Information Center

    Goldin, Gerald A., Ed.; McClintock, C. Edwin, Ed.

    A framework for research in problem solving is provided by categorizing and defining variables describing problem tasks. A model is presented in an article by Kulm for the classification of task variables into broad categories. The model attempts to draw realtionships between these categories of task variables and the stages of problem solving…

  13. Task Analysis: A Top-Down Approach.

    ERIC Educational Resources Information Center

    Harmon, Paul

    1983-01-01

    This approach to task analysis includes descriptions of (1) inputs, outputs, and jobs; (2) flow of materials and decisions between jobs; (3) inputs, major tasks, and outputs of each job; (4) sequence of steps for major tasks; (5) heuristics/algorithms for each sequence step; and (6) information needed to use heuristics algorithms. (EAO)

  14. Task Difficulty in Oral Speech Act Production

    ERIC Educational Resources Information Center

    Taguchi, Naoko

    2007-01-01

    This study took a pragmatic approach to examining the effects of task difficulty on L2 oral output. Twenty native English speakers and 59 Japanese students of English at two different proficiency levels produced speech acts of requests and refusals in a role play task. The task had two situation types based on three social variables:…

  15. Mathematics and Science Task Force Report.

    ERIC Educational Resources Information Center

    Wisconsin Univ., Green Bay. Inst. for Learning Partnership.

    This document presents a report from the Mathematics and Science Task Force. The Task Force held its initial meeting on January 27, 1999 to develop essential competencies in content knowledge and pedagogy in four areas: (1) elementary mathematics; (2) secondary mathematics; (3) elementary science; and (4) secondary science. Initially Task Force…

  16. Emergency Medical Technician Series. Duty Task List.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This document contains the occupational duty/task lists for 12 duties in the occupation of emergency medical technician. Each duty is divided into a number of tasks. A separate page for each duty lists the task with its code number and columns to indicate whether that particular duty has been taught and to provide space for comments. The 12 duties…

  17. Task Switching Effects in Anticipation Timing

    ERIC Educational Resources Information Center

    Fairbrother, Jeffrey T.; Brueckner, Sebastian

    2008-01-01

    To understand how task switching affects human performance, there is a need to investigate how it influences the performance of tasks other than those involving bivalent stimulus categorization. The purpose of this study, therefore, was to investigate the effects of task switching on anticipation timing performance, which typically requires…

  18. Working Memory Costs of Task Switching

    ERIC Educational Resources Information Center

    Liefooghe, Baptist; Barrouillet, Pierre; Vandierendonck, Andre; Camos, Valerie

    2008-01-01

    Although many accounts of task switching emphasize the importance of working memory as a substantial source of the switch cost, there is a lack of evidence demonstrating that task switching actually places additional demands on working memory. The present study addressed this issue by implementing task switching in continuous complex span tasks…

  19. Linking Task Analysis with Student Learning.

    ERIC Educational Resources Information Center

    Sherman, Thomas M.; Wildman, Terry M.

    An examination of task analysis from several perspectives in order to identify some of its purposes and advantages reveals that, as the interest in learning theory has shifted from a predominately behavioral perspective to a more cognitive orientation, the purpose of task analysis has also shifted. Formerly the purpose of task analysis was to aid…

  20. Human Performance on the Temporal Bisection Task

    ERIC Educational Resources Information Center

    Kopec, Charles D.; Brody, Carlos D.

    2010-01-01

    The perception and processing of temporal information are tasks the brain must continuously perform. These include measuring the duration of stimuli, storing duration information in memory, recalling such memories, and comparing two durations. How the brain accomplishes these tasks, however, is still open for debate. The temporal bisection task,…

  1. Task Proficiency and L1 Private Speech

    ERIC Educational Resources Information Center

    Yamada, Minako

    2005-01-01

    There is a growing volume of research on task-based language use; however, the nature of "task proficiency" has not yet been clearly defined. In order to gain new insights, this study examines the relationship between the process of communication in an L2 and a task outcome by analysing lexical density, as obtained from the pattern of a…

  2. Critical Issues in Telecollaborative Task Design

    ERIC Educational Resources Information Center

    O'Dowd, R.; Waire, P.

    2009-01-01

    In this article we examine how instructors make decisions about task design in telecollaboration and the factors that influence these decisions during the actual implementation of the tasks. We begin with a review of the recent literature of online intercultural exchanges to identify and describe a typology of 12 different types of tasks and task…

  3. The Potential of Statement-Posing Tasks

    ERIC Educational Resources Information Center

    Yang, Kai-Lin

    2010-01-01

    This communication aims at revealing the potential of statement-posing tasks to facilitate students' thinking and strategies of understanding proof. Besides outlining the background of statement-posing tasks, four points were advanced as potential benefits of the tasks: (1) focusing on the logic of arguments in addition to the meaning of…

  4. TASK-1 and TASK-3 may form heterodimers in human atrial cardiomyocytes.

    PubMed

    Rinné, Susanne; Kiper, Aytug K; Schlichthörl, Günter; Dittmann, Sven; Netter, Michael F; Limberg, Sven H; Silbernagel, Nicole; Zuzarte, Marylou; Moosdorf, Rainer; Wulf, Hinnerk; Schulze-Bahr, Eric; Rolfes, Caroline; Decher, Niels

    2015-04-01

    TASK-1 channels have emerged as promising drug targets against atrial fibrillation, the most common arrhythmia in the elderly. While TASK-3, the closest relative of TASK-1, was previously not described in cardiac tissue, we found a very prominent expression of TASK-3 in right human auricles. Immunocytochemistry experiments of human right auricular cardiomyocytes showed that TASK-3 is primarily localized at the plasma membrane. Single-channel recordings of right human auricles in the cell-attached mode, using divalent-cation-free solutions, revealed a TASK-1-like channel with a single-channel conductance of about 30pS. While homomeric TASK-3 channels were not found, we observed an intermediate single-channel conductance of about 55pS, possibly reflecting the heteromeric channel formed by TASK-1 and TASK-3. Subsequent experiments with TASK-1/TASK-3 tandem channels or with co-expressed TASK-1 and TASK-3 channels in HEK293 cells or Xenopus oocytes, supported that the 55pS channels observed in right auricles have electrophysiological characteristics of TASK-1/TASK-3 heteromers. In addition, co-expression experiments and single-channel recordings suggest that heteromeric TASK-1/TASK-3 channels have a predominant surface expression and a reduced affinity for TASK-1 blockers. In summary, the evidence for heteromeric TASK-1/TASK-3 channel complexes together with an altered pharmacologic response to TASK-1 blockers in vitro is likely to have further impact for studies isolating ITASK-1 from cardiomyocytes and for the development of drugs specifically targeting TASK-1 in atrial fibrillation treatment.

  5. Return to Flight Task Group

    NASA Technical Reports Server (NTRS)

    2005-01-01

    It has been 29 months since Columbia was lost over East Texas in February 2003. Seven months after the accident, the Columbia Accident Investigation Board (CAIB) released the first volume of its final report, citing a variety of technical, managerial, and cultural issues within NASA and the Space Shuttle Program. To their credit, NASA offered few excuses, embraced the report, and set about correcting the deficiencies noted by the accident board. Of the 29 recommendations issued by the CAIB, 15 were deemed critical enough that the accident board believed they should be implemented prior to returning the Space Shuttle to flight. Some of these recommendations were relatively easy, most were straightforward, a few bordered on the impossible, and others were largely overcome by events, particularly the decision by the President to retire the Space Shuttle by 2010. The Return to Flight Task Group (RTF TG, or simply, the Task Group) was chartered by the NASA Administrator in July 2003 to provide an independent assessment of the implementation of the 15 CAIB return-to-flight recommendations. An important observation must be stated up-front: neither the CAIB nor the RTF TG believes that all risk can be eliminated from Space Shuttle operations; nor do we believe that the Space Shuttle is inherently unsafe. What the CAIB and RTF TG do believe, however, is that NASA and the American public need to understand the risks associated with space travel, and that NASA must make every reasonable effort to minimize such risk. Since the release of the CAIB report, NASA and the Space Shuttle Program expended enormous effort and resources toward correcting the causes of the accident and preparing to fly again. Relative to the 15 specific recommendations that the CAIB indicated should be implemented prior to returning to flight, NASA has met or exceeded most of them the Task Group believes that NASA met the intent of the CAIB for 12 of these recommendations. The remaining three

  6. Autonomous organization of grasping tasks

    NASA Technical Reports Server (NTRS)

    Fiorini, Paolo; Chang, Jeffrey

    1989-01-01

    This paper describes an architecture for the control of robotic devices, and in particular of anthropomorphic hands, characterized by a hierarchical structure in which every level of the architecture contains data and control function with varying degree of abstraction. Bottom levels of the hierarchy interface directly with sensors and actuators, and process raw data and motor commands. Higher levels perform more symbolic types of tasks, such as application of Boolean rules and general planning operations. The implementation of the layer has to be consistent with the type of operation and its requirements for real time control. One implementation of the rule level, with a Boolean artificial neural network which would have a response time sufficient for producing reflex corrective action at the actuator level is presented.

  7. The numerical distance effect is task dependent.

    PubMed

    Goldfarb, Liat; Henik, Avishai; Rubinsten, Orly; Bloch-David, Yafit; Gertner, Limor

    2011-11-01

    Number comparison tasks produce a distance effect e.g., Moyer & Landauer (Nature 215: 1519-1520, 1967). It has been suggested that this effect supports the existence of semantic mental representations of numbers. In a matching task, a distance effect also appears, which suggests that the effect has an automatic semantic component. Recently, Cohen (Psychonomic Bulletin & Review 16: 332-336, 2009) suggested that in both automatic and intentional tasks, the distance effect might reflect not a semantic number representation, but a physical similarity between digits. The present article (1) compares the distance effect in the automatic matching task with that in the intentional number comparison task and suggests that, in the latter, the distance effect does include an additional semantic component; and (2) indicates that the distance effect in the standard automatic matching task is questionable and that its appearance in previous matching tasks was based on the specific analysis and design that were applied.

  8. Is a "Complex" Task Really Complex? Validating the Assumption of Cognitive Task Complexity

    ERIC Educational Resources Information Center

    Sasayama, Shoko

    2016-01-01

    In research on task-based learning and teaching, it has traditionally been assumed that differing degrees of cognitive task complexity can be inferred through task design and/or observations of differing qualities in linguistic production elicited by second language (L2) communication tasks. Without validating this assumption, however, it is…

  9. Is Performance in Task-Cuing Experiments Mediated by Task Set Selection or Associative Compound Retrieval?

    ERIC Educational Resources Information Center

    Forrest, Charlotte L. D.; Monsell, Stephen; McLaren, Ian P. L.

    2014-01-01

    Task-cuing experiments are usually intended to explore control of task set. But when small stimulus sets are used, they plausibly afford learning of the response associated with a combination of cue and stimulus, without reference to tasks. In 3 experiments we presented the typical trials of a task-cuing experiment: a cue (colored shape) followed,…

  10. Task Results Processing for the Needs of Task-Oriented Design Environments

    ERIC Educational Resources Information Center

    Zheliazkova, Irina; Kolev, R.

    2008-01-01

    This paper presents learners' task results gathered by means of an example task-oriented environment for knowledge testing and processed by EXCEL. The processing is domain- and task-independent and includes automatic calculation of several important task and session's parameters, drawing specific graphics, generating tables, and analyzing the…

  11. The Effect of a Workload-Preview on Task-Prioritization and Task-Performance

    ERIC Educational Resources Information Center

    Minotra, Dev

    2012-01-01

    With increased volume and sophistication of cyber attacks in recent years, maintaining situation awareness and effective task-prioritization strategy is critical to the task of cybersecurity analysts. However, high levels of mental-workload associated with the task of cybersecurity analyst's limits their ability to prioritize tasks.…

  12. How to Correct a Task Error: Task-Switch Effects Following Different Types of Error Correction

    ERIC Educational Resources Information Center

    Steinhauser, Marco

    2010-01-01

    It has been proposed that switch costs in task switching reflect the strengthening of task-related associations and that strengthening is triggered by response execution. The present study tested the hypothesis that only task-related responses are able to trigger strengthening. Effects of task strengthening caused by error corrections were…

  13. Cue-Independent Task-Specific Representations in Task Switching: Evidence from Backward Inhibition

    ERIC Educational Resources Information Center

    Altmann, Erik M.

    2007-01-01

    The compound-cue model of cognitive control in task switching explains switch cost in terms of a switch of task cues rather than of a switch of tasks. The present study asked whether the model generalizes to Lag 2 repetition cost (also known as backward inhibition), a related effect in which the switch from B to A in ABA task sequences is costlier…

  14. Investigating perfect timesharing: the relationship between IM-compatible tasks and dual-task performance.

    PubMed

    Halvorson, Kimberly M; Ebner, Herschel; Hazeltine, Eliot

    2013-04-01

    Why are dual-task costs reduced with ideomotor (IM) compatible tasks (Greenwald & Shulman, 1973; Lien, Proctor & Allen, 2002)? In the present experiments, we first examine three different measures of single-task performance (pure single-task blocks, mixed blocks, and long stimulus onset asynchrony [SOA] trials in dual-task blocks) and two measures of dual-task performance (simultaneous stimulus presentation blocks and simultaneous stimulus presentation trials in blocks with mixed SOAs), and show that these different measures produce different estimates of the cost. Next we examine whether the near elimination of costs can be explained by assuming that one or both of the tasks bypasses capacity-limited central operations. The results indicate that both tasks must be IM-compatible to nearly eliminate the dual-task costs, suggesting that the relationship between the tasks plays a critical role in overlapping performance. PMID:22866763

  15. On the importance of Task 1 and error performance measures in PRP dual-task studies

    PubMed Central

    Strobach, Tilo; Schütz, Anja; Schubert, Torsten

    2015-01-01

    The psychological refractory period (PRP) paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and Task 2) are presented with variable stimulus onset asynchronies (SOAs) and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e., decreasing SOAs do not increase reaction times (RTs) and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates) show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/or error rates in Task 1). This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects. PMID:25904890

  16. Assessing the Cost of Task Switching with a Three-Task Paradigm

    NASA Technical Reports Server (NTRS)

    Remington, Roger W.; Ruthruff, Eric; Johnston, James C.; Connors, Mary M. (Technical Monitor)

    1998-01-01

    To study task switching when subjects need not inhibit inappropriate responses, we examine tasks with non-overlapping stimulus sets (e.g. color patches and uncolored letters). A new three-task paradigm permits the dissociation of several otherwise confounded variables. We find that performance declines monotonically with increasing time since last performance of a task. Adjusting for the effects of this factor permits a fresh assessment of the relationship between task expectancy and recency (Ruthruff, Remington & Johnston, 1996).

  17. Tool and Task Analysis Guide for Vocational Welding (150 Tasks). Performance Based Vocational Education.

    ERIC Educational Resources Information Center

    John H. Hinds Area Vocational School, Elwood, IN.

    This book contains a task inventory, a task analysis of 150 tasks from that inventory, and a tool list for performance-based welding courses in the state of Indiana. The task inventory and tool list reflect 28 job titles found in Indiana. In the first part of the guide, tasks are listed by these domains: carbon-arc, electron beam, G.M.A.W., gas…

  18. Task 7: ADPAC User's Manual

    NASA Technical Reports Server (NTRS)

    Hall, E. J.; Topp, D. A.; Delaney, R. A.

    1996-01-01

    The overall objective of this study was to develop a 3-D numerical analysis for compressor casing treatment flowfields. The current version of the computer code resulting from this study is referred to as ADPAC (Advanced Ducted Propfan Analysis Codes-Version 7). This report is intended to serve as a computer program user's manual for the ADPAC code developed under Tasks 6 and 7 of the NASA Contract. The ADPAC program is based on a flexible multiple- block grid discretization scheme permitting coupled 2-D/3-D mesh block solutions with application to a wide variety of geometries. Aerodynamic calculations are based on a four-stage Runge-Kutta time-marching finite volume solution technique with added numerical dissipation. Steady flow predictions are accelerated by a multigrid procedure. An iterative implicit algorithm is available for rapid time-dependent flow calculations, and an advanced two equation turbulence model is incorporated to predict complex turbulent flows. The consolidated code generated during this study is capable of executing in either a serial or parallel computing mode from a single source code. Numerous examples are given in the form of test cases to demonstrate the utility of this approach for predicting the aerodynamics of modem turbomachinery configurations.

  19. Task-focused modeling in automated agriculture

    NASA Astrophysics Data System (ADS)

    Vriesenga, Mark R.; Peleg, K.; Sklansky, Jack

    1993-01-01

    Machine vision systems analyze image data to carry out automation tasks. Our interest is in machine vision systems that rely on models to achieve their designed task. When the model is interrogated from an a priori menu of questions, the model need not be complete. Instead, the machine vision system can use a partial model that contains a large amount of information in regions of interest and less information elsewhere. We propose an adaptive modeling scheme for machine vision, called task-focused modeling, which constructs a model having just sufficient detail to carry out the specified task. The model is detailed in regions of interest to the task and is less detailed elsewhere. This focusing effect saves time and reduces the computational effort expended by the machine vision system. We illustrate task-focused modeling by an example involving real-time micropropagation of plants in automated agriculture.

  20. Task-level control for autonomous robots

    NASA Technical Reports Server (NTRS)

    Simmons, Reid

    1994-01-01

    Task-level control refers to the integration and coordination of planning, perception, and real-time control to achieve given high-level goals. Autonomous mobile robots need task-level control to effectively achieve complex tasks in uncertain, dynamic environments. This paper describes the Task Control Architecture (TCA), an implemented system that provides commonly needed constructs for task-level control. Facilities provided by TCA include distributed communication, task decomposition and sequencing, resource management, monitoring and exception handling. TCA supports a design methodology in which robot systems are developed incrementally, starting first with deliberative plans that work in nominal situations, and then layering them with reactive behaviors that monitor plan execution and handle exceptions. To further support this approach, design and analysis tools are under development to provide ways of graphically viewing the system and validating its behavior.

  1. Cognate effects in bilingual language comprehension tasks.

    PubMed

    Yudes, Carolina; Macizo, Pedro; Bajo, Teresa

    2010-05-12

    We examined cognate effects when late fluent Spanish/English bilingual speakers undergoing event-related potential recordings performed two tasks on word pairs. In an association decision task, participants decided whether or not pairs of Spanish words were related in meaning. In a translation decision task, they reported whether English target words were correct translations of Spanish primes. In both the tasks, word primes were either cognates or noncognates. In the translation decision task, faster and more accurate responses were associated with reduced N400 amplitudes in word pairs featuring a cognate. However, cognates did not modulate performance or event-related potentials in the association decision task. The results suggest that language coactivation in bilingual speakers is modulated by cognitive context.

  2. A task control architecture for autonomous robots

    NASA Technical Reports Server (NTRS)

    Simmons, Reid; Mitchell, Tom

    1990-01-01

    An architecture is presented for controlling robots that have multiple tasks, operate in dynamic domains, and require a fair degree of autonomy. The architecture is built on several layers of functionality, including a distributed communication layer, a behavior layer for querying sensors, expanding goals, and executing commands, and a task level for managing the temporal aspects of planning and achieving goals, coordinating tasks, allocating resources, monitoring, and recovering from errors. Application to a legged planetary rover and an indoor mobile manipulator is described.

  3. Predictive performance models and multiple task performance

    NASA Technical Reports Server (NTRS)

    Wickens, Christopher D.; Larish, Inge; Contorer, Aaron

    1989-01-01

    Five models that predict how performance of multiple tasks will interact in complex task scenarios are discussed. The models are shown in terms of the assumptions they make about human operator divided attention. The different assumptions about attention are then empirically validated in a multitask helicopter flight simulation. It is concluded from this simulation that the most important assumption relates to the coding of demand level of different component tasks.

  4. The time line of threat processing and vagal withdrawal in response to a self-threatening stressor in cognitive avoidant copers: evidence for vigilance-avoidance theory.

    PubMed

    Schwerdtfeger, Andreas; Derakshan, Nazanin

    2010-07-01

    Using a spatial cueing paradigm with emotional and neutral facial expressions as cues, we examined early and late patterns of information processing in cognitive avoidant coping (CAV). Participants were required to detect a target that appeared either in the same location as the cue (valid) or in a different location (invalid). Cue-target onset asynchrony (CTOA) was manipulated to be short (250 ms) or long (750 ms). CAV was associated with early facilitation and faster disengagement from angry faces. No effects were found for happy or neutral faces. After completing the spatial cueing task, participants prepared and delivered a public speech and heart rate variability (HRV) was recorded. Disengagement from angry faces was related to a decrease in HRV in response to this task. Together, these data suggest that CAV is related to early engagement followed by disengagement from threat-related cues that might impact physiological stress responses.

  5. The functional neuroanatomy of multitasking: combining dual tasking with a short term memory task.

    PubMed

    Deprez, Sabine; Vandenbulcke, Mathieu; Peeters, Ron; Emsell, Louise; Amant, Frederic; Sunaert, Stefan

    2013-09-01

    Insight into the neural architecture of multitasking is crucial when investigating the pathophysiology of multitasking deficits in clinical populations. Presently, little is known about how the brain combines dual-tasking with a concurrent short-term memory task, despite the relevance of this mental operation in daily life and the frequency of complaints related to this process, in disease. In this study we aimed to examine how the brain responds when a memory task is added to dual-tasking. Thirty-three right-handed healthy volunteers (20 females, mean age 39.9 ± 5.8) were examined with functional brain imaging (fMRI). The paradigm consisted of two cross-modal single tasks (a visual and auditory temporal same-different task with short delay), a dual-task combining both single tasks simultaneously and a multi-task condition, combining the dual-task with an additional short-term memory task (temporal same-different visual task with long delay). Dual-tasking compared to both individual visual and auditory single tasks activated a predominantly right-sided fronto-parietal network and the cerebellum. When adding the additional short-term memory task, a larger and more bilateral frontoparietal network was recruited. We found enhanced activity during multitasking in components of the network that were already involved in dual-tasking, suggesting increased working memory demands, as well as recruitment of multitask-specific components including areas that are likely to be involved in online holding of visual stimuli in short-term memory such as occipito-temporal cortex. These results confirm concurrent neural processing of a visual short-term memory task during dual-tasking and provide evidence for an effective fMRI multitasking paradigm.

  6. Guessing versus Choosing an Upcoming Task

    PubMed Central

    Kleinsorge, Thomas; Scheil, Juliane

    2016-01-01

    We compared the effects of guessing vs. choosing an upcoming task. In a task-switching paradigm with four tasks, two groups of participants were asked to either guess or choose which task will be presented next under otherwise identical conditions. The upcoming task corresponded to participants’ guesses or choices in 75 % of the trials. However, only participants in the Choosing condition were correctly informed about this, whereas participants in the Guessing condition were told that tasks were determined at random. In the Guessing condition, we replicated previous findings of a pronounced reduction of switch costs in case of incorrect guesses. This switch cost reduction was considerably less pronounced with denied choices in the Choosing condition. We suggest that in the Choosing condition, the signaling of prediction errors associated with denied choices is attenuated because a certain proportion of denied choices is consistent with the overall representation of the situation as conveyed by task instructions. In the Guessing condition, in contrast, the mismatch of guessed and actual task is resolved solely on the level of individual trials by strengthening the representation of the actual task. PMID:27047423

  7. Guessing versus Choosing an Upcoming Task.

    PubMed

    Kleinsorge, Thomas; Scheil, Juliane

    2016-01-01

    We compared the effects of guessing vs. choosing an upcoming task. In a task-switching paradigm with four tasks, two groups of participants were asked to either guess or choose which task will be presented next under otherwise identical conditions. The upcoming task corresponded to participants' guesses or choices in 75 % of the trials. However, only participants in the Choosing condition were correctly informed about this, whereas participants in the Guessing condition were told that tasks were determined at random. In the Guessing condition, we replicated previous findings of a pronounced reduction of switch costs in case of incorrect guesses. This switch cost reduction was considerably less pronounced with denied choices in the Choosing condition. We suggest that in the Choosing condition, the signaling of prediction errors associated with denied choices is attenuated because a certain proportion of denied choices is consistent with the overall representation of the situation as conveyed by task instructions. In the Guessing condition, in contrast, the mismatch of guessed and actual task is resolved solely on the level of individual trials by strengthening the representation of the actual task. PMID:27047423

  8. Reasoning About Grasping From Task Descriptions

    NASA Astrophysics Data System (ADS)

    Liu, Huan; Iberall, Thea; Berkey, George A.

    1989-03-01

    The advent of multiple degree of freedom, dextrous robot hands has made robot hand control more complicated. Besides the existing problem of finding a suitable grasping position and ap-proach orientation, it is now necessary to decide the appropriate hand shape to use for a given task. In order to deal with this additional complexity, we focus on how to represent prehensile tasks for mapping task descriptions into suitable hand shapes, positions and orientations. A generic robot hand control system GeSAM is being implemented to refine task descriptions into suitable dextrous robot hand shapes using Knowledge Craft on a TI lisp machine.

  9. Dual-Task Processing When Task 1 Is Hard and Task 2 Is Easy: Reversed Central Processing Order?

    ERIC Educational Resources Information Center

    Leonhard, Tanja; Fernandez, Susana Ruiz; Ulrich, Rolf; Miller, Jeff

    2011-01-01

    Five psychological refractory period (PRP) experiments were conducted with an especially time-consuming first task (Experiments 1, 3, and 5: mental rotation; Experiments 2 and 4: memory scanning) and with equal emphasis on the first task and on the second (left-right tone judgment). The standard design with varying stimulus onset asynchronies…

  10. Muon Collider Task Force Report

    SciTech Connect

    Ankenbrandt, C.; Alexahin, Y.; Balbekov, V.; Barzi, E.; Bhat, C.; Broemmelsiek, D.; Bross, A.; Burov, A.; Drozhdin, A.; Finley, D.; Geer, S.; /Fermilab /Argonne /Brookhaven /Jefferson Lab /LBL, Berkeley /MUONS Inc., Batavia /UCLA /UC, Riverside /Mississippi U.

    2007-12-01

    Muon Colliders offer a possible long term path to lepton-lepton collisions at center-of-mass energies {radical}s {ge} 1 TeV. In October 2006 the Muon Collider Task Force (MCTF) proposed a program of advanced accelerator R&D aimed at developing the Muon Collider concept. The proposed R&D program was motivated by progress on Muon Collider design in general, and in particular, by new ideas that have emerged on muon cooling channel design. The scope of the proposed MCTF R&D program includes muon collider design studies, helical cooling channel design and simulation, high temperature superconducting solenoid studies, an experimental program using beams to test cooling channel RF cavities and a 6D cooling demonstration channel. The first year of MCTF activities are summarized in this report together with a brief description of the anticipated FY08 R&D activities. In its first year the MCTF has made progress on (1) Muon Collider ring studies, (2) 6D cooling channel design and simulation studies with an emphasis on the HCC scheme, (3) beam preparations for the first HPRF cavity beam test, (4) preparations for an HCC four-coil test, (5) further development of the MANX experiment ideas and studies of the muon beam possibilities at Fermilab, (6) studies of how to integrate RF into an HCC in preparation for a component development program, and (7) HTS conductor and magnet studies to prepare for an evaluation of the prospects for of an HTS high-field solenoid build for a muon cooling channel.

  11. TASK 2: QUENCH ZONE SIMULATION

    SciTech Connect

    Fusselman, Steve

    2015-09-30

    Aerojet Rocketdyne (AR) has developed an innovative gasifier concept incorporating advanced technologies in ultra-dense phase dry feed system, rapid mix injector, and advanced component cooling to significantly improve gasifier performance, life, and cost compared to commercially available state-of-the-art systems. A key feature of the AR gasifier design is the transition from the gasifier outlet into the quench zone, where the raw syngas is cooled to ~ 400°C by injection and vaporization of atomized water. Earlier pilot plant testing revealed a propensity for the original gasifier outlet design to accumulate slag in the outlet, leading to erratic syngas flow from the outlet. Subsequent design modifications successfully resolved this issue in the pilot plant gasifier. In order to gain greater insight into the physical phenomena occurring within this zone, AR developed a cold flow simulation apparatus with Coanda Research & Development with a high degree of similitude to hot fire conditions with the pilot scale gasifier design, and capable of accommodating a scaled-down quench zone for a demonstration-scale gasifier. The objective of this task was to validate similitude of the cold flow simulation model by comparison of pilot-scale outlet design performance, and to assess demonstration scale gasifier design feasibility from testing of a scaled-down outlet design. Test results did exhibit a strong correspondence with the two pilot scale outlet designs, indicating credible similitude for the cold flow simulation device. Testing of the scaled-down outlet revealed important considerations in the design and operation of the demonstration scale gasifier, in particular pertaining to the relative momentum between the downcoming raw syngas and the sprayed quench water and associated impacts on flow patterns within the quench zone. This report describes key findings from the test program, including assessment of pilot plant configuration simulations relative to actual

  12. Materials processing in space tasks. WBS task 5.4: Generic tasks

    NASA Technical Reports Server (NTRS)

    Crull, Robert

    1994-01-01

    This task encompassed a wide range of activities related to materials processing in space. For example, all aspects of the space station's flight and ground based systems design were assessed for the Office of Advanced Concepts and Technology (OACT) Space Processing Division Office. Activities for that organization also included the consolidation of space processing payload requirements for the space station and the development of an OACT payload operations plan. Similar duties were performed for the MSFC Payload Project Office. The SPACECOM database was used to conduct preliminary design studies for microgravity payload carriers and to conduct assessments of materials processing technology. Concepts for the Advanced Protein Crystal Growth Facility (APCGF) were developed. Materials processing vent products were analyzed and a furnace facility filter concept was developed using those studies. A preliminary design for a space station aluminum payload rack was developed. Analysis was conducted to characterize the acceleration environment onboard the space shuttle. Equipment for two fluid experiment apparatus was designed and manufactured for the Space Science Laboratory. The Fluids and Materials Experiments (FAME) data base was expanded. Also, Mir payload integration, technology transfer, and spacelab-to-space station transition studies were conducted.

  13. SOCIAL MEDIA MINING SHARED TASK WORKSHOP.

    PubMed

    Sarker, Abeed; Nikfarjam, Azadeh; Gonzalez, Graciela

    2016-01-01

    Social media has evolved into a crucial resource for obtaining large volumes of real-time information. The promise of social media has been realized by the public health domain, and recent research has addressed some important challenges in that domain by utilizing social media data. Tasks such as monitoring flu trends, viral disease outbreaks, medication abuse, and adverse drug reactions are some examples of studies where data from social media have been exploited. The focus of this workshop is to explore solutions to three important natural language processing challenges for domain-specific social media text: (i) text classification, (ii) information extraction, and (iii) concept normalization. To explore different approaches to solving these problems on social media data, we designed a shared task which was open to participants globally. We designed three tasks using our in-house annotated Twitter data on adverse drug reactions. Task 1 involved automatic classification of adverse drug reaction assertive user posts; Task 2 focused on extracting specific adverse drug reaction mentions from user posts; and Task 3, which was slightly ill-defined due to the complex nature of the problem, involved normalizing user mentions of adverse drug reactions to standardized concept IDs. A total of 11 teams participated, and a total of 24 (18 for Task 1, and 6 for Task 2) system runs were submitted. Following the evaluation of the systems, and an assessment of their innovation/novelty, we accepted 7 descriptive manuscripts for publication--5 for Task 1 and 2 for Task 2. We provide descriptions of the tasks, data, and participating systems in this paper.

  14. Control and Interference in Task Switching--A Review

    ERIC Educational Resources Information Center

    Kiesel, Andrea; Steinhauser, Marco; Wendt, Mike; Falkenstein, Michael; Jost, Kerstin; Philipp, Andrea M.; Koch, Iring

    2010-01-01

    The task-switching paradigm offers enormous possibilities to study cognitive control as well as task interference. The current review provides an overview of recent research on both topics. First, we review different experimental approaches to task switching, such as comparing mixed-task blocks with single-task blocks, predictable task-switching…

  15. Sequencing Writing Tasks on the Basis of Their Cognitive Demands.

    ERIC Educational Resources Information Center

    Sternglass, Marilyn

    An examination of student papers from three universities on the same tasks revealed that expository writing tasks were less demanding cognitively than argumentative writing tasks and that argumentative writing tasks were less demanding than speculative tasks. Another finding was that when students were able to translate a generalized task into…

  16. What Writing Tasks Do TESOL Professors Require?

    ERIC Educational Resources Information Center

    Cho, Hyonsuk

    2014-01-01

    Previous studies about writing assignments in higher education have explained that the library research paper, report on experiment, summary, and article/book review were the most common writing assignment tasks assigned across disciplines. No previous studies have explored writing tasks in the TESOL discipline at a national level. In this study…

  17. Improving Closing Task Completion in a Drugstore

    ERIC Educational Resources Information Center

    Fante, Rhiannon; Davis, Ora L.; Kempt, Vivian

    2013-01-01

    A within-subject ABAB reversal design was utilized to investigate the effects of graphic feedback and goal setting on employee closing task completion. Goal setting was contingent upon baseline performance and graphic feedback was posted weekly. It was found that goal setting and graphic feedback improved employee closing task completion.…

  18. Students' Views of Example Generation Tasks

    ERIC Educational Resources Information Center

    Breen, Sinead; O'Shea, Ann; Pfeiffer, Kirsten

    2016-01-01

    We report here on students' views of example generation tasks assigned to them in two first year undergraduate Calculus courses. The design and use of such tasks was undertaken as part of a project which aimed to afford students opportunities to develop their thinking skills and their conceptual understanding. In interviews with 10 students, we…

  19. The Ultimate Developmental Task in Adolescent Literature.

    ERIC Educational Resources Information Center

    Abrahamson, Richard F.

    The significance of adolescent literature has been judged on the basis of the developmental tasks encountered by the main character. One writer has identified eight developmental tasks that teenagers must undertake as they move toward adulthood: discovering one's sex role in our culture, developing relationships with peers, achieving an easy…

  20. Occupational Food Service Series. Duty Task List.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This document contains the occupational duty/task lists for six occupations in the occupational food service series. Each occupation is divided into three to eight duties. A separate page for each duty in the occupation lists the tasks in that duty along with its code number and columns to indicate whether that particular duty has been taught and…

  1. Cross Cultural Task Cards: Social Studies.

    ERIC Educational Resources Information Center

    Quinn, Jeanette; Carty, Elaine

    Twenty cross-cultural learning tasks focus on concepts developed through units on food, clothing, shelter, and natural resources. The tasks progress from simple to complex. They focus on concepts and vocabulary on culture, beginning with a discussion of housing and clothing and concluding with discussions on slavery and the Bill of Rights. Each…

  2. Using ADA Tasks to Simulate Operating Equipment

    NASA Technical Reports Server (NTRS)

    DeAcetis, Louis A.; Schmidt, Oron; Krishen, Kumar

    1990-01-01

    A method of simulating equipment using ADA tasks is discussed. Individual units of equipment are coded as concurrently running tasks that monitor and respond to input signals. This technique has been used in a simulation of the space-to-ground Communications and Tracking subsystem of Space Station Freedom.

  3. Posing Cognitively Demanding Tasks to All Students

    ERIC Educational Resources Information Center

    Lambert, Rachel; Stylianou, Despina A.

    2013-01-01

    Cognitively demanding tasks (CDT) (Stein et al. 2000) are necessary for the development of students' mathematical reasoning skills. Research is unequivocal on the importance of giving students opportunities to engage in such tasks. Although current reform efforts call for mathematics learning for "all" students, learners who…

  4. Auto Mechanics Series. Duty Task List.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This document contains the occupational duty/task lists for eight occupations in the auto mechanics series. Each occupation is divided into a number of duties. A separate page for each duty in the occupation lists the tasks in that duty along with its code number and columns to indicate whether that particular duty has been taught and to provide…

  5. Educational Office Personnel: Task List Competency Record.

    ERIC Educational Resources Information Center

    Minnesota Instructional Materials Center, White Bear Lake.

    One of 12 in the secretarial/clerical area, this booklet for vocational instructor contains a job description for educational office personnel, a task list of areas of competency, an occupational tasks competency record (suggested as replacement for the traditional report card), a list of industry representatives and educators involved in…

  6. Associate Degree Standards. Task Force Report.

    ERIC Educational Resources Information Center

    Minnesota Higher Education Coordinating Board, St. Paul.

    Developed by the Minnesota Higher Education Coordinating Board's (MHECB's) Task Force on Associate Degree Standards, this report recommends standards for all associate degrees granted by Minnesota post-secondary institutions. Chapter I provides introductory and background information on the creation and legislative charge of the task force and…

  7. Brief Family Therapy: A Metaphorical Task.

    ERIC Educational Resources Information Center

    de Shazer, Steve

    1980-01-01

    Presents a therapeutic procedure designed to prescribe the family's troublesome behavior pattern. A complement precedes delivering a task assignment. The metaphorical task redefines the serious complaint pattern into only one of the many options a family has for dealing with each other. A case study is presented. (Author/BEF)

  8. Task based synthesis of serial manipulators

    PubMed Central

    Patel, Sarosh; Sobh, Tarek

    2015-01-01

    Computing the optimal geometric structure of manipulators is one of the most intricate problems in contemporary robot kinematics. Robotic manipulators are designed and built to perform certain predetermined tasks. There is a very close relationship between the structure of the manipulator and its kinematic performance. It is therefore important to incorporate such task requirements during the design and synthesis of the robotic manipulators. Such task requirements and performance constraints can be specified in terms of the required end-effector positions, orientations and velocities along the task trajectory. In this work, we present a comprehensive method to develop the optimal geometric structure (DH parameters) of a non-redundant six degree of freedom serial manipulator from task descriptions. In this work we define, develop and test a methodology to design optimal manipulator configurations based on task descriptions. This methodology is devised to investigate all possible manipulator configurations that can satisfy the task performance requirements under imposed joint constraints. Out of all the possible structures, the structures that can reach all the task points with the required orientations are selected. Next, these candidate structures are tested to see whether they can attain end-effector velocities in arbitrary directions within the user defined joint constraints, so that they can deliver the best kinematic performance. Additionally least power consuming configurations are also identified. PMID:26257946

  9. Diesel Mechanics Series. Duty Task List.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This document contains the occupational duty/task lists for 11 occupations in the diesel mechanics series. Each occupation is divided into a number of duties. A separate page for each duty in the occupation lists the tasks in that duty along with its code number and columns to indicate whether that particular duty has been taught and to provide…

  10. Industrial Occupations. Education for Employment Task Lists.

    ERIC Educational Resources Information Center

    Lake County Area Vocational Center, Grayslake, IL.

    The duties and tasks found in these task lists form the basis of instructional content for secondary, postsecondary, and adult occupational training programs for industrial occupations. The industrial occupations are divided into eight clusters. The clusters and occupations are: construction cluster (bricklayer, carpenter, building maintenance…

  11. Regulative Loops, Step Loops and Task Loops

    ERIC Educational Resources Information Center

    VanLehn, Kurt

    2016-01-01

    This commentary suggests a generalization of the conception of the behavior of tutoring systems, which the target article characterized as having an outer loop that was executed once per task and an inner loop that was executed once per step of the task. A more general conception sees these two loops as instances of regulative loops, which…

  12. Agricultural Occupations. Education for Employment Task Lists.

    ERIC Educational Resources Information Center

    Lake County Area Vocational Center, Grayslake, IL.

    The duties and tasks found in these task lists form the basis of instructional content for secondary, postsecondary, and adult occupational training programs for agricultural occupations. The agricultural occupations are divided into three clusters. The clusters and occupations are: agricultural business and management cluster…

  13. Metacognition in Monkeys during an Oculomotor Task

    ERIC Educational Resources Information Center

    Middlebrooks, Paul G.; Sommer, Marc A.

    2011-01-01

    This study investigated whether rhesus monkeys show evidence of metacognition in a reduced, visual oculomotor task that is particularly suitable for use in fMRI and electrophysiology. The 2-stage task involved punctate visual stimulation and saccadic eye movement responses. In each trial, monkeys made a decision and then made a bet. To earn…

  14. Mathematically Rich, Investigative Tasks for Teaching Algebra

    ERIC Educational Resources Information Center

    Day, Lorraine

    2015-01-01

    A challenge for teachers is to incorporate the Standards for Mathematical Practice (CCSSI 2010) throughout their teaching of mathematics so that the Common Core Standards do not revert back to a purely content-driven curriculum. One way to achieve this is through the use of mathematically rich, investigative tasks. These tasks encourage students…

  15. What Is Task-Centered Learning?

    ERIC Educational Resources Information Center

    Francom, Gregory M.; Gardner, Joel

    2014-01-01

    Many recent models of learning and instruction center learning on real-world tasks and problems to support knowledge application and transfer. Of the many different approaches to centering learning on real-world tasks and problems, one main area in recent literature attempts to balance the efficiency of adequate learner support with the…

  16. Residential Carpentry Series. Duty Task List.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This document contains the occupational duty/task lists for nine occupations in the residential carpentry series. Each occupation is divided into a number of duties. A separate page for each duty in the occupation lists the tasks in that duty along with its code number and columns to indicate whether that particular duty has been taught and to…

  17. Investigating Quadrilaterals as an Ongoing Task

    ERIC Educational Resources Information Center

    Richardson, Kerri; Schwartz, Catherine Stein; Reynolds, Anne

    2010-01-01

    In this article we discuss an open-ended problem involving quadrilaterals that we continually offer each semester. The task has been posed to undergraduate and graduate students in methods and problem solving classes. The task involves drawing all possible four sided figures with corners at the dots. A four by four array of dots is included in the…

  18. Task 5: Architecture sensitivity to STME performance

    NASA Astrophysics Data System (ADS)

    Schnackel, J. A.

    1992-09-01

    This document was prepared for Task 5: Architecture Sensitivity to Space Transportation Main Engine (STME) Performance. Information provided in this report documents the architecture sensitivities with respect to STME performance parameters. Suggested STME thrust level was driven by Task 5 sensitivities and Task 4 vehicle configurations. Recommendations on STME thrust level are presented in this report. Sensitivities to STME parameters and vehicle system parameters were evaluated. Design of Experiment (DOE) approaches were used to understand the relative importance of each parameter. Suggested sensitivity parameters and their respective ranges were provided to the Task 5 lead. Our recommendation on analysis approach for the sensitivities was a central composite faced design. Task 5 sensitivities should be updated following final Task 4 architecture recommendations. A suggested analysis approach is provided in the analysis section of this report (Part C, Appendix I, Analysis). This analysis approach was used on Advanced Launch System (ALS) Phase 2 to improve the evaluation of alternate engine designs and vehicle subsystem evaluations. It is suggested that the analysis approach outlined in Part C be utilized to update Task when final Task 4 architecture information is available. Contents of this submittal include: Part A, Narrative Summary; Part B, View Graphs with facing page text; Part C, Appendix I, Analysis Part C, Appendix II, Data.

  19. Aircraft Mechanics Series. Duty Task List.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This task list is intended for use in planning and/or evaluating a competency-based course in aircraft mechanics. The guide outlines the tasks entailed in 24 different duties typically required of employees in the following occupations: airframe mechanic, power plant mechanic, aircraft mechanic, aircraft sheet metal worker, aircraft electrician,…

  20. Instructional Objectives: Selecting and Devising Tasks

    ERIC Educational Resources Information Center

    Mileff, Milo

    2013-01-01

    In the present paper and the discussion that follows, the author presents aspects of test construction and a careful description of instructional objectives. Constructing tests involves several stages such as describing language objectives, selecting appropriate test task, devising and assembling test tasks, and devising a scoring system for…

  1. Concurrent Cognitive Task Modulates Coordination Dynamics

    ERIC Educational Resources Information Center

    Pellecchia, Geraldine L.; Shockley, Kevin; Turvey, M. T.

    2005-01-01

    Does a concurrent cognitive task affect the dynamics of bimanual rhythmic coordination? In-phase coordination was performed under manipulations of phase detuning and movement frequency and either singly or in combination with an arithmetic task. Predicted direction-specific shifts in stable relative phase from 0 degrees due to detuning and…

  2. Shaping Academic Task Engagement with Percentile Schedules

    ERIC Educational Resources Information Center

    Athens, Elizabeth S.; Vollmer, Timothy R.; St. Peter Pipkin, Claire C.

    2007-01-01

    The purpose of this study was to examine the use of percentile schedules as a method of quantifying the shaping procedure in an educational setting. We compared duration of task engagement during baseline measurements for 4 students to duration of task engagement during a percentile schedule. As a secondary purpose, we examined the influence on…

  3. Optimization: Old Dogs and New Tasks

    ERIC Educational Resources Information Center

    Kaplan, Jennifer J.; Otten, Samuel

    2012-01-01

    This article introduces an optimization task with a ready-made motivating question that may be paraphrased as follows: "Are you smarter than a Welsh corgi?" The authors present the task along with descriptions of the ways in which two groups of students approached it. These group vignettes reveal as much about the nature of calculus students'…

  4. Using Perceptrons to Explore the Reorientation Task

    ERIC Educational Resources Information Center

    Dawson, Michael R. W.; Kelly, Debbie M.; Spetch, Marcia L.; Dupuis, Brian

    2010-01-01

    The reorientation task is a paradigm that has been used extensively to study the types of information used by humans and animals to navigate in their environment. In this task, subjects are reinforced for going to a particular location in an arena that is typically rectangular in shape. The subject then has to find that location again after being…

  5. A Bilingual Advantage in Task Switching

    ERIC Educational Resources Information Center

    Prior, Anat; MacWhinney, Brian

    2010-01-01

    This study investigated the possibility that lifelong bilingualism may lead to enhanced efficiency in the ability to shift between mental sets. We compared the performance of monolingual and fluent bilingual college students in a task-switching paradigm. Bilinguals incurred reduced switching costs in the task-switching paradigm when compared with…

  6. Ecology and Task Structures in Adventure Education

    ERIC Educational Resources Information Center

    Zmudy, Mark H.; Curtner-Smith, Matthew D.; Steffen, Jeff

    2009-01-01

    Many of the characteristics of effective physical education lessons have been discovered by sport pedagogy researchers by employing what has become known as the ecological or task structures perspective. The purpose of this study was to describe the task structures and ecology that existed in two consecutive 7-day summer adventure camps run by an…

  7. Machine Tool Series. Duty Task List.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This task list is intended for use in planning and/or evaluating a competency-based course to prepare machine tool, drill press, grinding machine, lathe, mill, and/or power saw operators. The listing is divided into six sections, with each one outlining the tasks required to perform the duties that have been identified for the given occupation.…

  8. The Keck Task Library (KTL)

    NASA Technical Reports Server (NTRS)

    Lupton, W. F.; Conrad, A. R.

    1992-01-01

    KTL is a set of routines which eases the job of writing applications which must interact with a variety of underlying sub-systems (known as services). A typical application is an X Window user interface coordinating telescope and instruments. In order to connect to a service, application code specifies a service name--typically an instrument name--and a style, which defines the way in which the application will interact with the service. Two styles are currently supported: keyword, where the application reads and writes named keywords and the resulting inter-task message traffic is hidden; and message, where the application deals directly with messages. The keyword style is intended mainly for user interfaces, and the message style is intended mainly for lower-level applications. KTL applications are event driven: a typical application first connects to all its desired services, then expresses interest in specified events. The application then enters an event dispatch loop in which it waits for events and calls the appropriate service's event-handling routine. Each event is associated with a call-back routine which is invoked when the event occurs. Call-back routines may (and typically do) interact with other sub-systems and KTL provides the means of doing so without blocking the application (vital for X Window user interfaces). This approach is a marriage of ideas culled from the X window, ADAM, Keck instrument, and Keck telescope control systems. A novel feature of KTL is that it knows nothing about any services or styles. Instead it defines a generic set of routines which must be implemented by all services and styles (essentially open(), ioctl(), read(), write(), event(), and close()) and activates sharable libraries at run-time. Services have been implemented (in both keyword and message styles) for HIRES (the Keck high resolution echelle spectrograph built by Lick Observatory), LWS (the Keck long wavelength spectrometer built by UC San Diego), and the Keck

  9. Working memory effects in speeded RSVP tasks.

    PubMed

    Gil-Gómez de Liaño, Beatriz; Potter, Mary C; Rodríguez, Carmen

    2014-01-01

    The present paper examines the effects of memory contents and memory load in rapid serial visual presentation (RSVP) speeded tasks, trying to explain previous inconsistent results. We used a one target (Experiment 1) and a two-target (Experiment 2) RSVP task with a concurrent memory load of one or four items, in a dual-task paradigm. A relation between material in working memory and the target in the RSVP impaired the identification of the target. In Experiments 3 and 4, the single task was to determine whether any information in memory matched the target in the RSVP, while varying the memory load. A match was detected faster than a non-match, although only when there was some distance between targets in the RSVP (Experiment 4). The results suggest that memory contents automatically capture attention, slowing processing when the memory contents are irrelevant to the task, and speeding processing when they are relevant.

  10. Task mapping for non-contiguous allocations.

    SciTech Connect

    Leung, Vitus Joseph; Bunde, David P.; Ebbers, Johnathan; Price, Nicholas W.; Swank, Matthew.; Feer, Stefan P.; Rhodes, Zachary D.

    2013-02-01

    This paper examines task mapping algorithms for non-contiguously allocated parallel jobs. Several studies have shown that task placement affects job running time for both contiguously and non-contiguously allocated jobs. Traditionally, work on task mapping either uses a very general model where the job has an arbitrary communication pattern or assumes that jobs are allocated contiguously, making them completely isolated from each other. A middle ground between these two cases is the mapping problem for non-contiguous jobs having a specific communication pattern. We propose several task mapping algorithms for jobs with a stencil communication pattern and evaluate them using experiments and simulations. Our strategies improve the running time of a MiniApp by as much as 30% over a baseline strategy. Furthermore, this improvement increases markedly with the job size, demonstrating the importance of task mapping as systems grow toward exascale.

  11. MULTITASK FEATURE SELECTION WITH TASK DESCRIPTORS.

    PubMed

    Bellón, Víctor; Stoven, Véronique; Azencott, Chloé-Agathe

    2016-01-01

    Machine learning applications in precision medicine are severely limited by the scarcity of data to learn from. Indeed, training data often contains many more features than samples. To alleviate the resulting statistical issues, the multitask learning framework proposes to learn different but related tasks jointly, rather than independently, by sharing information between these tasks. Within this framework, the joint regularization of model parameters results in models with few non-zero coefficients and that share similar sparsity patterns. We propose a new regularized multitask approach that incorporates task descriptors, hence modulating the amount of information shared between tasks according to their similarity. We show on simulated data that this method outperforms other multitask feature selection approaches, particularly in the case of scarce data. In addition, we demonstrate on peptide MHC-I binding data the ability of the proposed approach to make predictions for new tasks for which no training data is available. PMID:26776192

  12. Learning to Model Task-Oriented Attention

    PubMed Central

    Zou, Xiaochun; Zhao, Xinbo; Wang, Jian; Yang, Yongjia

    2016-01-01

    For many applications in graphics, design, and human computer interaction, it is essential to understand where humans look in a scene with a particular task. Models of saliency can be used to predict fixation locations, but a large body of previous saliency models focused on free-viewing task. They are based on bottom-up computation that does not consider task-oriented image semantics and often does not match actual eye movements. To address this problem, we collected eye tracking data of 11 subjects when they performed some particular search task in 1307 images and annotation data of 2,511 segmented objects with fine contours and 8 semantic attributes. Using this database as training and testing examples, we learn a model of saliency based on bottom-up image features and target position feature. Experimental results demonstrate the importance of the target information in the prediction of task-oriented visual attention. PMID:27247561

  13. Robot Task Commander with Extensible Programming Environment

    NASA Technical Reports Server (NTRS)

    Hart, Stephen W (Inventor); Yamokoski, John D. (Inventor); Wightman, Brian J (Inventor); Dinh, Duy Paul (Inventor); Gooding, Dustin R (Inventor)

    2014-01-01

    A system for developing distributed robot application-level software includes a robot having an associated control module which controls motion of the robot in response to a commanded task, and a robot task commander (RTC) in networked communication with the control module over a network transport layer (NTL). The RTC includes a script engine(s) and a GUI, with a processor and a centralized library of library blocks constructed from an interpretive computer programming code and having input and output connections. The GUI provides access to a Visual Programming Language (VPL) environment and a text editor. In executing a method, the VPL is opened, a task for the robot is built from the code library blocks, and data is assigned to input and output connections identifying input and output data for each block. A task sequence(s) is sent to the control module(s) over the NTL to command execution of the task.

  14. Task-specific dystonia: pathophysiology and management.

    PubMed

    Sadnicka, Anna; Kassavetis, Panagiotis; Pareés, Isabel; Meppelink, Anne Marthe; Butler, Katherine; Edwards, Mark

    2016-09-01

    Task-specific dystonia is a form of isolated focal dystonia with the peculiarity of being displayed only during performance of a specific skilled motor task. This distinctive feature makes task-specific dystonia a particularly mysterious and fascinating neurological condition. In this review, we cover phenomenology and its increasingly broad-spectrum risk factors for the disease, critically review pathophysiological theories and evaluate current therapeutic options. We conclude by highlighting the unique features of task-specific dystonia within the wider concept of dystonia. We emphasise the central contribution of environmental risk factors, and propose a model by which these triggers may impact on the motor control of skilled movement. By viewing task-specific dystonia through this new lens which considers the disorder a modifiable disorder of motor control, we are optimistic that research will yield novel therapeutic avenues for this highly motivated group of patients.

  15. Working memory effects in speeded RSVP tasks.

    PubMed

    Gil-Gómez de Liaño, Beatriz; Potter, Mary C; Rodríguez, Carmen

    2014-01-01

    The present paper examines the effects of memory contents and memory load in rapid serial visual presentation (RSVP) speeded tasks, trying to explain previous inconsistent results. We used a one target (Experiment 1) and a two-target (Experiment 2) RSVP task with a concurrent memory load of one or four items, in a dual-task paradigm. A relation between material in working memory and the target in the RSVP impaired the identification of the target. In Experiments 3 and 4, the single task was to determine whether any information in memory matched the target in the RSVP, while varying the memory load. A match was detected faster than a non-match, although only when there was some distance between targets in the RSVP (Experiment 4). The results suggest that memory contents automatically capture attention, slowing processing when the memory contents are irrelevant to the task, and speeding processing when they are relevant. PMID:23397260

  16. The Task Is Not Enough: Processing Approaches to Task-Based Performance

    ERIC Educational Resources Information Center

    Skehan, Peter; Xiaoyue, Bei; Qian, Li; Wang, Zhan

    2012-01-01

    This article reports on three research studies, all of which concern second language task performance. The first focuses on planning, and compares on-line and strategic planning as well as task repetition. The second study examines the role of familiarity on task performance, and compares this with conventional strategic planning. The third study…

  17. Task Inventory Construction. Evaluation of the Marine Corps Task Analysis Program. Technical Report No. 14.

    ERIC Educational Resources Information Center

    Kishi, Akemi

    To aid in the construction of effective task analysis inventories, this technical report discusses: (1) an optimum questionnaire length that adequately covers Marine tasks without unduly fatiguing respondents; (2) procedures for the phrasing of task statements to avoid ambiguities and be understandable to as broad a range of Marines as is…

  18. The Effects of Self-Esteem and Task Perception on Goal Setting, Efficacy, and Task Performance.

    ERIC Educational Resources Information Center

    Tang, Thomas Li-Ping; Reynolds, David Bryan

    This study examined the effects of self-esteem and task perception on goal setting, efficacy, and task performance in 52 recreational dart throwers who were members of two dart organizations. Task perception was manipulated by asking each dart thrower to compete against self, a difficult competitor, and an easy competitor on the same dart game.…

  19. Stimulus-based priming of task choice during voluntary task switching.

    PubMed

    Arrington, Catherine M; Weaver, Starla M; Pauker, Rachel L

    2010-07-01

    Two voluntary task-switching experiments probed the influence of previous exposures to stimuli and categorizations of these stimuli on task choice during subsequent exposures to the same stimuli. Subjects performed origin and size judgments under standard voluntary task-switching instructions to perform the tasks equally often in a random order. Both when subjects voluntarily selected the task on the first exposure (Experiment 1) and when the experimenter manipulated the task on the first exposure (Experiment 2), subjects chose to perform the same task on subsequent exposures significantly more often than would be expected on the basis of the instructions to perform tasks in a random order. Presentation of a previously encountered stimulus may result in the retrieval of a stimulus-task binding or event file that biases task selection as well as task readiness. The pattern of data across the 2 experiments suggests that stimulus-based priming influences task choice through both retrieval of episodes within the context of the experiment and semantic memory mechanisms.

  20. The Unconscious Allocation of Cognitive Resources to Task-Relevant and Task-Irrelevant Thoughts

    ERIC Educational Resources Information Center

    Kuldas, Seffetullah; Hashim, Shahabuddin; Ismail, Hairul Nizam; Samsudin, Mohd Ali; Bakar, Zainudin Abu

    2014-01-01

    Conscious allocation of cognitive resources to task-relevant thoughts is necessary for learning. However, task-irrelevant thoughts often associated with fear of failure can enter the mind and interfere with learning. Effects like this prompt the question of whether or not learners consciously shift their cognitive resources from task-relevant to…