WorldWideScience

Sample records for reward-based performance decrements

  1. Age-related decrements in cycling and running performance ...

    African Journals Online (AJOL)

    South African Journal of Sports Medicine ... This study examined age-related decrements in athletic performance during running and cycling activities. ... These findings establish a trend that there is 'accelerated' aging during running which can perhaps be attributed to the increased weight-bearing stress on the muscles ...

  2. Protection against radiation-induced performance decrement in mice

    International Nuclear Information System (INIS)

    Mukherjee, S.K.; Pant, Kanchan; Goel, H.C.; Jain, Viney

    1997-01-01

    Recognizing that there is lack of information on the effects of low-level ionizing radiations and the modifying role of radioprotectors, an attempt has been made in this study to explore the relationship between impairment of spatial learning and low level of radiation exposure. A radial arm maze was utilised to evaluate radiation-induced behavioural alterations and performance decrement in mice. Immediately after whole body exposure to gamma radiation (absorbed dose, 1 Gy) significant perturbations in the learned behaviour of the animals were observed. The regular control movement became irregular and the food consumption time was reduced appreciably (40%). Recovery took place in four days. If diltiazem (7 mg/kg b.w.), a Ca 2+ channel blocker and a radioprotector, was administered i.p. 20-30 min prior to irradiation, radiation-induced behavioural abnormalities were reduced. Mechanisms underlying protection by diltiazem against radiation-induced performance decrement observed in the present study need to be investigated. (author). 23 refs., 2 figs

  3. Decrement in manual arm performance during whole body cooling.

    Science.gov (United States)

    Giesbrecht, G G; Bristow, G K

    1992-12-01

    Six subjects performed three manual arm tasks: 1) prior to immersion in 8 degrees C water; 2) soon after immersion to the neck, but prior to any decrease in core temperature; and 3) every 15 min until core temperatures decreased 2-4.5 degrees C. The tasks were speed of flexion and extension of the fingers, handgrip strength and manual dexterity. There was no immediate effect of cold immersion; however, all scores decreased significantly after core temperature decreased 0.5 degrees C. Further decrease in core temperature was associated with a progressive impairment of performance, although at a slower rate than during the first 0.5 degrees C decrease. Flexion and extension of the fingers was affected relatively more than handgrip strength or manual dexterity. Decrement in performance is a result of peripheral cooling on sensorimotor function with a probable additional effect of central cooling on cerebral function.

  4. Delayed match-to-sample early performance decrement in monkeys after 60Co irradiation

    International Nuclear Information System (INIS)

    Bruner, A.; Bogo, V.; Jones, R.K.

    1975-01-01

    Sixteen monkeys were trained on a delayed match-to-sample task (DMTS) based on shock avoidance and irradiated with single, whole-body exposures of from 396 to 2000 rad 60 Co (midbody dose) at between 163 and 233 rad/min. Pre- to post-irradiation performance changes were assessed using a penalty-scaling measure which differentially weighted incorrect responses, response omissions, and error-omission sequences. Thirteen of the animals displayed early performance decrement, including five incapacitations, at lower doses (less than 1000 rad) than heretofore found effective. This was considered a function of task complexity, measurement sensitivity, and gamma effectiveness. The minimum effective midbody dose for inducing decrement using the DMTS task was estimated to be on the order of 500 rad. The nature of early, transient performance decrement seems to reflect more of an inability to perform than an inability to perform correctly

  5. Hot and Hypoxic Environments Inhibit Simulated Soccer Performance and Exacerbate Performance Decrements When Combined

    Science.gov (United States)

    Aldous, Jeffrey W. F.; Chrismas, Bryna C. R.; Akubat, Ibrahim; Dascombe, Ben; Abt, Grant; Taylor, Lee

    2016-01-01

    The effects of heat and/or hypoxia have been well-documented in match-play data. However, large match-to-match variation for key physical performance measures makes environmental inferences difficult to ascertain from soccer match-play. Therefore, the present study aims to investigate the hot (HOT), hypoxic (HYP), and hot-hypoxic (HH) mediated-decrements during a non-motorized treadmill based soccer-specific simulation. Twelve male University soccer players completed three familiarization sessions and four randomized crossover experimental trials of the intermittent Soccer Performance Test (iSPT) in normoxic-temperate (CON: 18°C 50% rH), HOT (30°C; 50% rH), HYP (1000 m; 18°C 50% rH), and HH (1000 m; 30°C; 50% rH). Physical performance and its performance decrements, body temperatures (rectal, skin, and estimated muscle temperature), heart rate (HR), arterial blood oxygen saturation (SaO2), perceived exertion, thermal sensation (TS), body mass changes, blood lactate, and plasma volume were all measured. Performance decrements were similar in HOT and HYP [Total Distance (−4%), High-speed distance (~−8%), and variable run distance (~−12%) covered] and exacerbated in HH [total distance (−9%), high-speed distance (−15%), and variable run distance (−15%)] compared to CON. Peak sprint speed, was 4% greater in HOT compared with CON and HYP and 7% greater in HH. Sprint distance covered was unchanged (p > 0.05) in HOT and HYP and only decreased in HH (−8%) compared with CON. Body mass (−2%), temperatures (+2–5%), and TS (+18%) were altered in HOT. Furthermore, SaO2 (−8%) and HR (+3%) were changed in HYP. Similar changes in body mass and temperatures, HR, TS, and SaO2 were evident in HH to HOT and HYP, however, blood lactate (p physical performance during iSPT. Future interventions should address the increases in TS and body temperatures, to attenuate these decrements on soccer performance. PMID:26793122

  6. Impact of window decrement rate on TCP performance in an adhoc network

    Science.gov (United States)

    Suherman; Hutasuhut, Arief T. W.; Badra, Khaldun; Al-Akaidi, Marwan

    2017-09-01

    Transmission control protocol (TCP) is a reliable transport protocol handling end to end connection in TCP/IP stack. It works well in copper or optical fibre link, but experiences increasing delay in wireless network. Further, TCP experiences multiple retransmissions due to higher collision probability within wireless network. The situation may get worsen in an ad hoc network. This paper examines the impact half window or window reduction rate to the overall TCP performances. The evaluation using NS-2 simulator shows that the smaller the window decrement rate results the smaller end to end delay. Delay is reduced to 17.05% in average when window decrement rate decreases. Average jitter also decreases 4.15%, while packet loss is not affected.

  7. Nursing Performance and Mobile Phone Use: Are Nurses Aware of Their Performance Decrements?

    Science.gov (United States)

    McBride, Deborah; LeVasseur, Sandra A; Li, Dongmei

    2015-04-23

    Prior research has documented the effect of concurrent mobile phone use on medical care. This study examined the extent of hospital registered nurses' awareness of their mobile-phone-associated performance decrements. The objective of this study was to compare self-reported performance with reported observed performance of others with respect to mobile phone use by hospital registered nurses. In March 2014, a previously validated survey was emailed to the 10,978 members of the Academy of Medical Surgical Nurses. The responses were analyzed using a two-proportion z test (alpha=.05, two-tailed) to examine whether self-reported and observed rates of error were significantly different. All possible demographic and employment confounders which could potentially contribute to self-reported and observed performance errors were tested for significance. Of the 950 respondents, 825 (8.68%, 825/950) met the inclusion criteria for analysis. The representativeness of the sample relative to the US nursing workforce was assessed using a two-proportion z test. This indicated that sex and location of primary place of employment (urban/rural) were represented appropriately in the study sample. Respondents in the age groups 55 years old were overrepresented. Whites, American Indians/Alaskan natives, and Native Hawaiian or Pacific Islanders were underrepresented, while Hispanic and multiple/other ethnicities were overrepresented. It was decided to report the unweighted, rather than the weighted survey data, with the recognition that the results, while valuable, may not be generalizable to the entire US registered nursing workforce. A significant difference was found between registered nurses' self-reported and observed rates of errors associated with concurrent mobile phone use in following three categories (1) work performance (z=-26.6142, Pmobile phone use by nurses at work was a serious distraction; always (13%, 107/825), often (29.6%, 244/825), sometimes (44.6%, 368/825), rarely

  8. Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J.C.; Ibrahim, S.R.; Brincker, Rune

    Abstraet Thispaper demansirates how to use the Random Decrement (RD) technique for identification o flinear structures subjected to ambient excitation. The theory behind the technique will be presented and guidelines how to choose the different variables will be given. This is done by introducing...

  9. Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Ibrahim, S. R.; Brincker, Rune

    This paper demonstrates how to use the Random Decrement (RD) technique for identification of linear structures subjected to ambient excitation. The theory behind the technique will be presented and guidelines how to choose the different variables will be given. This is done by introducing a new...

  10. Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Ibrahim, R.; Brincker, Rune

    1998-01-01

    This paper demonstrates how to use the Random Decrement (RD) technique for identification of linear structures subjected to ambient excitation. The theory behind the technique will be presented and guidelines how to choose the different variables will be given. This is done by introducing a new...

  11. Sleep deprivation and time-on-task performance decrement in the rat psychomotor vigilance task.

    Science.gov (United States)

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

    2015-03-01

    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. 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. The study was conducted in an academic research vivarium. 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. Rats performed the rPVT for 30 min at baseline and after 24 h total sleep deprivation by gentle handling. 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. The rPVT manifests similarities to the hPVT in global performance outcomes, but not in post-sleep deprivation effects of time on task and response-stimulus interval. © 2015 Associated Professional Sleep Societies, LLC.

  12. Choking under pressure: The neuropsychological mechanisms for incentives induced performance decrements

    Directory of Open Access Journals (Sweden)

    Rongjun eYu

    2015-02-01

    Full Text Available In contrast to the assumption of efficiency wage models, which state that wage incentives should be positively correlated with productivity, high incentives may produce performance decrements in real life scenarios. Such a choking under pressure phenomenon exemplifies how psychological stress can profoundly shape human behavior, for good or for bad. Previous theories suggest that individual choking under pressure because that high pressure may distract individuals’ attention away from the task (the distraction account, raise the attention paid to step-by-step skill processes (the explicit monitoring account, or elevate the arousal in general (the over-arousal account. Recent neuroimaging studies have shown that several brain regions implicated in motivation and top-down control of attention also play a key role in stress-induced choking, supporting for the over-arousal and distraction theories of choking. This review aims to identify psychological factors that determine choking and the neural underpinnings of these processes. Insights into how incentives influence performance may aid engineering training regimens and interventions that equip individuals to better handle high-stakes-induced psychological stress, and to thrive under stress.

  13. Instant messaging addiction among teenagers in China: shyness, alienation, and academic performance decrement.

    Science.gov (United States)

    Huang, Hanyun; Leung, Louis

    2009-12-01

    This exploratory research proposes the concept of instant messaging (IM) addiction and examines (a) whether IM addiction exists among Chinese teenagers and, if so, who the addicts are, what their symptoms are, and to what extent they are addicted; (b) whether psychological variables such as shyness and alienation can predict IM use or addiction among teenagers; and (c) whether IM use or IM addiction can impair the academic performance of teenagers. Using Young's classic definition of Internet addiction, results of a stratified random sample of 330 teenagers in China in 2007 found 95.8% of participants use IM, and 9.8% of them can be classified as IM addicts. Factor analysis identified four major IM addiction symptoms among teenagers: preoccupation with IM, loss of relationships due to overuse, loss of control, and escape. Results also showed that shyness and alienation from family, peers, and school are significantly and positively associated with levels of IM addiction. As expected, both the level of IM use and level of IM addiction are significantly linked to teenagers' academic performance decrement.

  14. Memory load as a cognitive antidote to performance decrements in data entry.

    Science.gov (United States)

    Chapman, Mary J; Healy, Alice F; Kole, James A

    2016-10-01

    In two experiments, subjects trained in data entry, typing one 4-digit number at a time. At training, subjects either typed the numbers immediately after they appeared (immediate) or typed the previous number from memory while viewing the next number (delayed). In Experiment 2 stimulus presentation time was limited and either nothing or a space (gap) was inserted between the second and third digits. In both experiments after training, all subjects completed a test with no gap and typed numbers immediately. Training with a memory load improved speed across training blocks (Experiment 1) and eliminated the decline in accuracy across training blocks (Experiment 2), thus serving as a cognitive antidote to performance decrements. An analysis of each keystroke revealed different underlying processes and strategies for the two training conditions, including when encoding took place. Chunking (in which the first and last two digits are treated separately) was more evident in the immediate than in the delayed condition and was exaggerated with a gap, even at test when there was no gap. These results suggest that such two-digit chunking is due to stimulus encoding and motor planning processes as well as memory, and those processes transferred from training to testing.

  15. Understanding Performance Decrements in a Letter-Canceling Task: Overcoming Habits or Inhibition of Reading.

    Science.gov (United States)

    Myers, Larry; Downie, Steven; Taylor, Grant; Marrington, Jessica; Tehan, Gerald; Ireland, Michael J

    2018-01-01

    The importance of self-regulation in human behavior is readily apparent and diverse theoretical accounts for explaining self-regulation failures have been proposed. Typically, these accounts are based on a sequential task methodology where an initial task is presented to deplete self-regulatory resources, and carryover effects are then examined on a second outcome task. In the aftermath of high profile replication failures using a popular letter-crossing task as a means of depleting self-regulatory resources and subsequent criticisms of that task, current research into self-control is currently at an impasse. This is largely due to the lack of empirical research that tests explicit assumptions regarding the initial task. One such untested assumption is that for resource depletion to occur, the initial task must first establish an habitual response and then this habitual response must be inhibited, with behavioral inhibition being the causal factor in inducing depletion. This study reports on four experiments exploring performance on a letter-canceling task, where the rules for target identification remained constant but the method of responding differed (Experiment 1) and the coherence of the text was manipulated (Experiments 1-4). Experiment 1 established that habit forming and behavioral inhibition did not produce any performance decrement when the targets were embedded in random letter strings. Experiments 2-4 established that target detection was sensitive to language characteristics and the coherence of the background text, suggesting that participants' automatic reading processes is a key driver of performance in the letter-e task.

  16. Decrements in knee extensor and flexor strength are associated with performance fatigue during simulated basketball game-play in adolescent, male players.

    Science.gov (United States)

    Scanlan, Aaron T; Fox, Jordan L; Borges, Nattai R; Delextrat, Anne; Spiteri, Tania; Dalbo, Vincent J; Stanton, Robert; Kean, Crystal O

    2018-04-01

    This study quantified lower-limb strength decrements and assessed the relationships between strength decrements and performance fatigue during simulated basketball. Ten adolescent, male basketball players completed a circuit-based, basketball simulation. Sprint and jump performance were assessed during each circuit, with knee flexion and extension peak concentric torques measured at baseline, half-time, and full-time. Decrement scores were calculated for all measures. Mean knee flexor strength decrement was significantly (P jump fatigue during the entire game. Lower-limb strength decrements may exert an important influence on performance fatigue during basketball activity in adolescent, male players. Consequently, training plans should aim to mitigate lower-limb fatigue to optimise sprint and jump performance during game-play.

  17. Risk of Performance Decrement and Crew Illness Due to an Inadequate Food System

    Science.gov (United States)

    Douglas, Grace L.; Cooper, Maya; Bermudez-Aguirre, Daniela; Sirmons, Takiyah

    2016-01-01

    evidence for the Risk of Performance Decrement and Crew Illness Due to an Inadequate Food System and the gaps in relation to exploration, as identified by the NASA Human Research Program (HRP). The research reviewed here indicates strategies to establish methods, technologies, and requirements that increase food stability, support adequate nutrition, quality, and variety, enable supplementation with grow-pick-and-eat salad crops, ensure safety, and reduce resource use. Obtaining the evidence to establish an adequate food system is essential, as the resources allocated to the food system may be defined based on the data relating nutritional stability and food quality requirements to crew performance and health.

  18. Risk of Adverse Health Outcomes and Decrements in Performance Due to In-flight Medical Conditions

    Science.gov (United States)

    Antonsen,Erik

    2017-01-01

    The drive to undertake long-duration space exploration missions at greater distances from Earth gives rise to many challenges concerning human performance under extreme conditions. At NASA, the Human Research Program (HRP) has been established to investigate the specific risks to astronaut health and performance presented by space exploration, in addition to developing necessary countermeasures and technology to reduce risk and facilitate safer, more productive missions in space (NASA Human Research Program 2009). The HRP is divided into five subsections, covering behavioral health, space radiation, habitability, and other areas of interest. Within this structure is the ExMC Element, whose research contributes to the overall development of new technologies to overcome the challenges of expanding human exploration and habitation of space. The risk statement provided by the HRP to the ExMC Element states: "Given that medical conditions/events will occur during human spaceflight missions, there is a possibility of adverse health outcomes and decrements in performance in mission and for long term health" (NASA Human Research Program 2016). Within this risk context, the Exploration Medical Capabilities (ExMC) Element is specifically concerned with establishing evidenced-based methods of monitoring and maintaining astronaut health. Essential to completing this task is the advancement in techniques that identify, prevent, and treat any health threats that may occur during space missions. The ultimate goal of the ExMC Element is to develop and demonstrate a pathway for medical system integration into vehicle and mission design to mitigate the risk of medical issues. Integral to this effort is inclusion of an evidence-based medical and data handling system appropriate for long-duration, exploration-class missions. This requires a clear Concept of Operations, quantitative risk metrics or other tools to address changing risk throughout a mission, and system scoping and system

  19. Physiological correlates of stress-induced decrements in human perceptual performance.

    Science.gov (United States)

    1993-11-01

    Stress-induced changes in human performance have been thought to result from alterations in the "multidimensional arousal state" of the individual, as indexed by alterations in the physiological and psychological mechanisms controlling performance. I...

  20. Work performance decrements are associated with Australian working conditions, particularly the demand to work longer hours.

    Science.gov (United States)

    Holden, Libby; Scuffham, Paul A; Hilton, Michael F; Vecchio, Nerina N; Whiteford, Harvey A

    2010-03-01

    To demonstrate the importance of including a range of working conditions in models exploring the association between health- and work-related performance. The Australian Work Outcomes Research Cost-benefit study cross-sectional screening data set was used to explore health-related absenteeism and work performance losses on a sample of approximately 78,000 working Australians, including available demographic and working condition factors. Data collected using the World Health Organization Health and Productivity Questionnaire were analyzed with negative binomial logistic regression and multinomial logistic regressions for absenteeism and work performance, respectively. Hours expected to work, annual wage, and job insecurity play a vital role in the association between health- and work-related performance for both work attendance and self-reported work performance. Australian working conditions are contributing to both absenteeism and low work performance, regardless of health status.

  1. Decrements in Human Performance During 72-84 Hours of Sustained Operations

    National Research Council Canada - National Science Library

    Castellani, John W; Nindl, Bradley C; Lieberman, Harris R; Montain, Scott J

    2006-01-01

    ...). On the previous week, subjects were not sleep deprived or in a negative energy balance (CONTROL week). Subjects completed a battery of physical and cognitive performance tests and a cold-air test on each week at various time points...

  2. Mathematical Modeling of Physical and Cognitive Performance Decrement from Mechanical and Inhalation Insults

    National Research Council Canada - National Science Library

    Stuhmiller, James H; Bykanova, Lucy; Chan, Philemon; Dang, Xinglai; Fournier, Adam; Long, Diane W; Lu, Zi; Masiello, Paul; Ng, Laurel; Niu, Eugene

    2006-01-01

    This report summarizes the first year of a 5-year program to develop physiologically and biomechanically based mathematical models that will allow the estimation of physical and cognitive performance...

  3. Mathematical Modeling of Physical and Cognitive Performance Decrement from Mechanical and Inhalation Insults

    Science.gov (United States)

    2009-12-01

    12  2.1.5  The effect of hypoxia and carboxyhemoglobin concentration on exercise performance in goats...B.L., Ng, L., and Stuhmiller, J.H. “The effects of hypoxia and carboxyhemoglobin concentration on a ‘phenomenological’ model’s recovery parameter...State. 2.1.5 The effect of hypoxia and carboxyhemoglobin concentration on exercise performance in goats The purpose of this study was to quantify if

  4. Exercise as Countermeasure for Decrements of Performance and Mood During Long-Term Confinement

    Science.gov (United States)

    Schneider, Stefan; Piacentini, Maria F.; Meeusen, Romain; Brummer, Vera; Struder, Heiko K.

    2008-06-01

    In order to prepare for crewed exploratory missions to Moon and Mars, currently ESA is participating in two isolation studies, MARS 500 and on the antarctis station CONCORDIA. The aim of the present study is to identify exercise as a countermeasure to confinement addicted changes in mood. It is planned (1) to look at influences of exercise on the serotonergic system, which is known to have mood regulating effects and (2) to record changes in brain cortical activity due to exercise. Mood and performance tests will be carried out several times during the confinement. We hypothesize that impairments in mood due to the isolated and confined environment together with a lack of physical exercise lead to decreases in mental and perceptual motor performance whereas physical exercise linked with an activation of the serotonergic system will improve mood and therefore performance irrespectively of the environmental restrictions.

  5. Can We Predict Cognitive Performance Decrements Due to Sleep Loss and the Recuperative Effects of Caffeine

    Science.gov (United States)

    2015-10-14

    the integrated UMP would provide another step toward the development of a wearable computer-based system or smartphone app that considers an......mail.mil ABSTRACT Warfighters are often subjected to challenging sleep/wake schedules that hinder their cognitive performance. Countermeasures

  6. CONTRIBUTION OF COGNITIVE INTERFERENCE TO DECREMENTS IN WALKING PERFORMANCE IN HEMODIALYSIS PATIENTS

    Directory of Open Access Journals (Sweden)

    Ken Wilund

    2012-06-01

    These data indicate that walking impairments in hemodialysis patients are not due exclusively to declines in physical function, but that cognitive-motor interference also plays a significant role. This has significant clinical importance, as therapies designed to improve walking performance and physical function, such as nutritional and exercise interventions, may need to be augmented with cognitive training in order to have maximum benefits.

  7. cfDNA as an Earlier Predictor of Exercise-Induced Performance Decrement Related to Muscle Damage.

    Science.gov (United States)

    Andreatta, Michely V; Curty, Victor M; Coutinho, João Victor S; Santos, Miguel Ângelo A; Vassallo, Paula F; de Sousa, Nuno F; Barauna, Valério G

    2017-11-28

    The aims of this study were: a) to evaluate whether cell-free DNA (cfDNA) levels increase immediately after an acute light and heavy resistance exercise (RE) bout, and b) to whether cfDNA levels are associated with functional muscle capacity until 48hrs after exercise session. Twenty healthy volunteers performed 3 sets of the leg press resistance exercise with 80% of 1RM (RE80) or 40% of 1RM (RE40) with similar exercise volume. Blood lactate was measured after completion of the 3 sets. Creatine kinase (CK), cfDNA and jump performance were evaluated before (pre) exercise, immediately post-exercise (Post-0) and every 24hrs until 48hrs. Lactate concentration increased similarly in both groups (RE40, 4.0±1.3mmol/L; RE80, 4.8±1.3mmol/L). No changes were observed in squat jump and countermovement jump performance after RE40, however both jumps remained reduced until 48h in RE80 group. CK concentration increased post-24h only in the RE80 group (Pre: 128.8±73.7U/L to Post-24h: 313.8±116.4U/L). cfDNA concentration increased post-0h only in the RE80 group (Pre, 249.8±82.3ng/mL; Post-0h, 406.3±67.2ng/mL). There was a negative correlation between post-0h cfDNA concentration and post-24h squat jump (r=-0.521; p=0.01) and post-0h cfDNA concentration and post-24h countermovement jump (r=-0.539; p=0.01). cfDNA increases in responsive to RE intensity even when not performed until exhaustion. cfDNA measured immediately after RE is a promising biomarker for muscle performance decrement until 48hrs of a RE bout.

  8. Risk of Performance Decrements and Adverse Health Outcomes Resulting from Sleep Loss, Circadian Desynchronization, and Work Overload

    Science.gov (United States)

    Flynn-Evans, Erin; Gregory, Kevin; Arsintescu, Lucia; Whitmire, Alexandra

    2016-01-01

    Sleep loss, circadian desynchronization, and work overload occur to some extent for ground and flight crews, prior to and during spaceflight missions. Ground evidence indicates that such risk factors may lead to performance decrements and adverse health outcomes, which could potentially compromise mission objectives. Efforts are needed to identify the environmental and mission conditions that interfere with sleep and circadian alignment, as well as individual differences in vulnerability and resiliency to sleep loss and circadian desynchronization. Specifically, this report highlights a collection of new evidence to better characterize the risk and reveals new gaps in this risk as follows: Sleep loss is apparent during spaceflight. Astronauts consistently average less sleep during spaceflight relative to on the ground. The causes of this sleep loss remain unknown, however ground-based evidence suggests that the sleep duration of astronauts is likely to lead to performance impairment and short and long-term health consequences. Further research is needed in this area in order to develop screening tools to assess individual astronaut sleep need in order to quantify the magnitude of sleep loss during spaceflight; current and planned efforts in BHP's research portfolio address this need. In addition, it is still unclear whether the conditions of spaceflight environment lead to sleep loss or whether other factors, such as work overload lead to the reduced sleep duration. Future data mining efforts and continued data collection on the ISS will help to further characterize factors contributing to sleep loss. Sleep inertia has not been evaluated during spaceflight. Ground-based studies confirm that it takes two to four hours to achieve optimal performance after waking from a sleep episode. Sleep inertia has been associated with increased accidents and reduced performance in operational environments. Sleep inertia poses considerable risk during spaceflight when emergency

  9. Immediate changes in estimated cardiac output and vascular resistance after 60Co exposure in monkeys: implication for performance decrement

    International Nuclear Information System (INIS)

    Bruner, A.

    1977-01-01

    Aortic blood flow velocity, blood pressure, and heart rate were recorded in 12 unanesthetized, nonperforming monkeys during exposure to 1000 rad 60 Co at 129--164 rad/min. The first postradiation changes were seen within 3--4 min of the exposure's start and included tachycardia, a transient hypotension secondary to a loss in peripheral resistance, and a brief increase followed by a decrease to subnormal levels in cardiac output. The lowest cardiac output occurred between 10 and 20 min postexposure while blood pressure and peripheral resistance were recovering. It was proposed that the concurrent combination of low cardiac output, low blood pressure, and supranormal peripheral resistance might sufficiently attenuate cerebral perfusion temporarily to account for the transient behavioral decrements often seen during this time. Histamine release was postulated as responsible for this vascular shock syndrome

  10. Use of the accelerating rotarod for assessment of motor performance decrement induced by potential anticonvulsant compounds in nerve agent poisoning. (Reannouncement with new availability information)

    Energy Technology Data Exchange (ETDEWEB)

    Capacio, B.R.; Harris, L.W.; Anderson, D.R.; Lennox, W.J.; Gales, V.

    1992-12-31

    The accelerating rotarod was used to assess motor performance decrement in rats after administration of candidate anticonvulsant compounds (acetazolamide, amitriptyline, chlordiazepoxide, diazepan, diazepam-lysine, lorazepam, loprazolam, midazolam, phenobarbital and scopolamine) against nerve agent poisoning. AH compounds were tested as the commercially available injectable preparation except for diazepam-lysine and loprazolam, which are not FDA approved. A peak effect time, as well as a dose to decrease performance time by 50% from control (PDD50), was determined. The calculated PDD50 (micrometer ol/kg) values and peak effect tunes were midazolam, 1.16 at 15 min; loprazolam, 1.17 at 15 min; diazepam-lysine, 4.17 at 30 min; lorazepwn, 4.98 at 15 min; diazepam, 5.27 at 15 min; phenobarbital, 101.49 at 45 min; chlordiazepoxide, 159.21 at 30 min; scopolamine, amitriptyline and acetazolamide did not demonstrate a performance decrement at any of the doses tested. The PDD50 values were compared with doses which have been utilized against nerve agent-induced convulsions or published ED50 values from standard anticonvulsant screening tests (maximal electroshock MES and subcutaneous pentylenetetrazol (scMET)). I serve agents, anticonvulsants, diazepam, accelerating rotarod, motor performance.

  11. Decrement in operant performance produced by NMDA receptor antagonists in the rat: tolerance and cross-tolerance.

    Science.gov (United States)

    Dravolina, O A; Zvartau, E E; Bespalov, A Y

    2000-04-01

    Current perspectives on the clinical use of NMDA receptor antagonists infer repeated administration schedules for the management of different pathological states. The development of tolerance and cross-tolerance between different NMDA receptor antagonists may be an important factor contributing to the clinical efficacy of these drugs. The present study aimed to characterize the development of tolerance and cross-tolerance to the ability of various site-selective NMDA receptor antagonists to produce a decrement of operant responding (multiple extinction 9 s fixed-interval 1-s schedule of water reinforcement). Acute administration of D-CPPen (SDZ EAA 494; 1-5.6 mg/kg), dizocilpine (MK-801; 0.03-0.3 mg/kg), memantine (0.3-17 mg/kg), ACEA-1021 (10-56 mg/kg), and eliprodil (1-30 mg/kg) differentially affected operant responding. Both increases and decreases in response rates and accuracy of responding were observed. Repeated preexposure to D-CPPen (5.6 mg/kg, once a day for 7 days) attenuated a behavioral disruption produced by an acute challenge with D-CPPen or ACEA-1021, but potentiated the effects of dizocilpine, memantine, and eliprodil. Based on the present results, one can suggest that the repeated administration of a competitive NMDA receptor antagonist differentially affects the functional activity of various sites on NMDA receptor complex.

  12. Random Decrement Based FRF Estimation

    DEFF Research Database (Denmark)

    Brincker, Rune; Asmussen, J. C.

    to speed and quality. The basis of the new method is the Fourier transformation of the Random Decrement functions which can be used to estimate the frequency response functions. The investigations are based on load and response measurements of a laboratory model of a 3 span bridge. By applying both methods...... that the Random Decrement technique is based on a simple controlled averaging of time segments of the load and response processes. Furthermore, the Random Decrement technique is expected to produce reliable results. The Random Decrement technique will reduce leakage, since the Fourier transformation...

  13. Random Decrement Based FRF Estimation

    DEFF Research Database (Denmark)

    Brincker, Rune; Asmussen, J. C.

    1997-01-01

    to speed and quality. The basis of the new method is the Fourier transformation of the Random Decrement functions which can be used to estimate the frequency response functions. The investigations are based on load and response measurements of a laboratory model of a 3 span bridge. By applying both methods...... that the Random Decrement technique is based on a simple controlled averaging of time segments of the load and response processes. Furthermore, the Random Decrement technique is expected to produce reliable results. The Random Decrement technique will reduce leakage, since the Fourier transformation...

  14. Impairment of probabilistic reward-based learning in schizophrenia.

    Science.gov (United States)

    Weiler, Julia A; Bellebaum, Christian; Brüne, Martin; Juckel, Georg; Daum, Irene

    2009-09-01

    Recent models assume that some symptoms of schizophrenia originate from defective reward processing mechanisms. Understanding the precise nature of reward-based learning impairments might thus make an important contribution to the understanding of schizophrenia and the development of treatment strategies. The present study investigated several features of probabilistic reward-based stimulus association learning, namely the acquisition of initial contingencies, reversal learning, generalization abilities, and the effects of reward magnitude. Compared to healthy controls, individuals with schizophrenia exhibited attenuated overall performance during acquisition, whereas learning rates across blocks were similar to the rates of controls. On the group level, persons with schizophrenia were, however, unable to learn the reversal of the initial reward contingencies. Exploratory analysis of only the subgroup of individuals with schizophrenia who showed significant learning during acquisition yielded deficits in reversal learning with low reward magnitudes only. There was further evidence of a mild generalization impairment of the persons with schizophrenia in an acquired equivalence task. In summary, although there was evidence of intact basic processing of reward magnitudes, individuals with schizophrenia were impaired at using this feedback for the adaptive guidance of behavior.

  15. Risk of Performance and Behavioral Health Decrements Due to Inadequate Cooperation, Coordination, Communication, and Psychosocial Adaptation within a Team

    Science.gov (United States)

    Landon, Lauren Blackwell; Vessey, William B.; Barrett, Jamie D.

    2015-01-01

    A team is defined as: "two or more individuals who interact socially and adaptively, have shared or common goals, and hold meaningful task interdependences; it is hierarchically structured and has a limited life span; in it expertise and roles are distributed; and it is embedded within an organization/environmental context that influences and is influenced by ongoing processes and performance outcomes" (Salas, Stagl, Burke, & Goodwin, 2007, p. 189). From the NASA perspective, a team is commonly understood to be a collection of individuals that is assigned to support and achieve a particular mission. Thus, depending on context, this definition can encompass both the spaceflight crew and the individuals and teams in the larger multi-team system who are assigned to support that crew during a mission. The Team Risk outcomes of interest are predominantly performance related, with a secondary emphasis on long-term health; this is somewhat unique in the NASA HRP in that most Risk areas are medically related and primarily focused on long-term health consequences. In many operational environments (e.g., aviation), performance is assessed as the avoidance of errors. However, the research on performance errors is ambiguous. It implies that actions may be dichotomized into "correct" or "incorrect" responses, where incorrect responses or errors are always undesirable. Researchers have argued that this dichotomy is a harmful oversimplification, and it would be more productive to focus on the variability of human performance and how organizations can manage that variability (Hollnagel, Woods, & Leveson, 2006) (Category III1). Two problems occur when focusing on performance errors: 1) the errors are infrequent and, therefore, difficult to observe and record; and 2) the errors do not directly correspond to failure. Research reveals that humans are fairly adept at correcting or compensating for performance errors before such errors result in recognizable or recordable failures

  16. Age-related decrements in dual-task performance: Comparison of different mobility and cognitive tasks. A cross sectional study.

    Science.gov (United States)

    Brustio, Paolo Riccardo; Magistro, Daniele; Zecca, Massimiliano; Rabaglietti, Emanuela; Liubicich, Monica Emma

    2017-01-01

    This cross-sectional study investigated the age-related differences in dual-task performance both in mobility and cognitive tasks and the additive dual-task costs in a sample of older, middle-aged and young adults. 74 older adults (M = 72.63±5.57 years), 58 middle-aged adults (M = 46.69±4.68 years) and 63 young adults (M = 25.34±3.00 years) participated in the study. Participants performed different mobility and subtraction tasks under both single- and dual-task conditions. Linear regressions, repeated-measures and one-way analyses of covariance were used, The results showed: significant effects of the age on the dual and mobility tasks (ptask costs (pperformance under dual-task conditions in all groups (pperformance in the older group (ptask activity affected mobility and cognitive performance, especially in older adults who showed a higher dual-task cost, suggesting that dual-tasks activities are affected by the age and consequently also mobility and cognitive tasks are negatively influenced.

  17. Reward-based spatial crowdsourcing with differential privacy preservation

    Science.gov (United States)

    Xiong, Ping; Zhang, Lefeng; Zhu, Tianqing

    2017-11-01

    In recent years, the popularity of mobile devices has transformed spatial crowdsourcing (SC) into a novel mode for performing complicated projects. Workers can perform tasks at specified locations in return for rewards offered by employers. Existing methods ensure the efficiency of their systems by submitting the workers' exact locations to a centralised server for task assignment, which can lead to privacy violations. Thus, implementing crowsourcing applications while preserving the privacy of workers' location is a key issue that needs to be tackled. We propose a reward-based SC method that achieves acceptable utility as measured by task assignment success rates, while efficiently preserving privacy. A differential privacy model ensures rigorous privacy guarantee, and Laplace noise is introduced to protect workers' exact locations. We then present a reward allocation mechanism that adjusts each piece of the reward for a task using the distribution of the workers' locations. Through experimental results, we demonstrate that this optimised-reward method is efficient for SC applications.

  18. Strategies for reward-based crowdfunding campaigns

    Directory of Open Access Journals (Sweden)

    Sascha Kraus

    2016-01-01

    Full Text Available Crowdfunding represents an alternative way of funding entrepreneurial ventures – and is attracting a high amount of interest in research as well as practice. Against this background, this paper analyzes reward-based crowdfunding campaign strategies and their communication tools. To do this, 446 crowdfunding projects were gathered and empirically analyzed. Three different paths of successful crowdfunding projects could be identified and are described in detail. Practical implications of crowdfunding strategies are derived, and are dependent on the required sales effort and the project added value. The terms communicator, networker and self-runner are created for this crowdfunding strategy and filled with practical examples. This paper contributes to the literature in different ways: first, it sheds more light on the developing concept of crowdfunding, with an overview of current academic discussions on crowdfunding. Furthermore, the analysis of success factors for crowdfunding initiatives adds to an emerging area of research and allows entrepreneurs to extract best practice examples for increasing the probability of successful crowdfunding projects under consideration of the key influencing factors of communication.

  19. Probiotic Streptococcus thermophilus FP4 and Bifidobacterium breve BR03 Supplementation Attenuates Performance and Range-of-Motion Decrements Following Muscle Damaging Exercise

    Directory of Open Access Journals (Sweden)

    Ralf Jäger

    2016-10-01

    Full Text Available Probiotics have immunomodulatory effects. However, little is known about the potential benefit of probiotics on the inflammation subsequent to strenuous exercise. In a double-blind, randomized, placebo controlled, crossover design separated by a 21-day washout, 15 healthy resistance-trained men ingested an encapsulated probiotic Streptococcus (S. thermophilus FP4 and Bifidobacterium (B. breve BR03 at 5 bn live cells (AFU concentration each, or a placebo, daily for 3 weeks prior to muscle-damaging exercise (ClinicalTrials.gov NCT02520583. Isometric strength, muscle soreness, range of motion and girth, and blood interleukin-6 (IL-6 and creatine kinase (CK concentrations were measured from pre- to 72 h post-exercise. Statistical analysis was via mixed models and magnitude-based inference to the standardized difference. Probiotic supplementation resulted in an overall decrease in circulating IL-6, which was sustained to 48 h post-exercise. In addition, probiotic supplementation likely enhanced isometric average peak torque production at 24 to 72 h into the recovery period following exercise (probiotic–placebo point effect ±90% CI: 24 h, 11% ± 7%; 48 h, 12% ± 18%; 72 h, 8% ± 8%. Probiotics also likely moderately increased resting arm angle at 24 h (2.4% ± 2.0% and 48 h (1.9% ± 1.9% following exercise, but effects on soreness and flexed arm angle and CK were unclear. These data suggest that dietary supplementation with probiotic strains S. thermophilus FP4 and B. breve BR03 attenuates performance decrements and muscle tension in the days following muscle-damaging exercise.

  20. Probiotic Streptococcus thermophilus FP4 and Bifidobacterium breve BR03 Supplementation Attenuates Performance and Range-of-Motion Decrements Following Muscle Damaging Exercise.

    Science.gov (United States)

    Jäger, Ralf; Purpura, Martin; Stone, Jason D; Turner, Stephanie M; Anzalone, Anthony J; Eimerbrink, Micah J; Pane, Marco; Amoruso, Angela; Rowlands, David S; Oliver, Jonathan M

    2016-10-14

    Probiotics have immunomodulatory effects. However, little is known about the potential benefit of probiotics on the inflammation subsequent to strenuous exercise. In a double-blind, randomized, placebo controlled, crossover design separated by a 21-day washout, 15 healthy resistance-trained men ingested an encapsulated probiotic Streptococcus ( S. ) thermophilus FP4 and Bifidobacterium ( B. ) breve BR03 at 5 bn live cells (AFU) concentration each, or a placebo, daily for 3 weeks prior to muscle-damaging exercise (ClinicalTrials.gov NCT02520583). Isometric strength, muscle soreness, range of motion and girth, and blood interleukin-6 (IL-6) and creatine kinase (CK) concentrations were measured from pre- to 72 h post-exercise. Statistical analysis was via mixed models and magnitude-based inference to the standardized difference. Probiotic supplementation resulted in an overall decrease in circulating IL-6, which was sustained to 48 h post-exercise. In addition, probiotic supplementation likely enhanced isometric average peak torque production at 24 to 72 h into the recovery period following exercise (probiotic-placebo point effect ±90% CI: 24 h, 11% ± 7%; 48 h, 12% ± 18%; 72 h, 8% ± 8%). Probiotics also likely moderately increased resting arm angle at 24 h (2.4% ± 2.0%) and 48 h (1.9% ± 1.9%) following exercise, but effects on soreness and flexed arm angle and CK were unclear. These data suggest that dietary supplementation with probiotic strains S. thermophilus FP4 and B. breve BR03 attenuates performance decrements and muscle tension in the days following muscle-damaging exercise.

  1. Combining Correlation-Based and Reward-Based Learning in Neural Control for Policy Improvement

    DEFF Research Database (Denmark)

    Manoonpong, Poramate; Kolodziejski, Christoph; Wörgötter, Florentin

    2013-01-01

    Classical conditioning (conventionally modeled as correlation-based learning) and operant conditioning (conventionally modeled as reinforcement learning or reward-based learning) have been found in biological systems. Evidence shows that these two mechanisms strongly involve learning about...... associations. Based on these biological findings, we propose a new learning model to achieve successful control policies for artificial systems. This model combines correlation-based learning using input correlation learning (ICO learning) and reward-based learning using continuous actor–critic reinforcement...... learning (RL), thereby working as a dual learner system. The model performance is evaluated by simulations of a cart-pole system as a dynamic motion control problem and a mobile robot system as a goal-directed behavior control problem. Results show that the model can strongly improve pole balancing control...

  2. Chewing gum moderates the vigilance decrement.

    OpenAIRE

    Morgan, K.; Johnson, A.J.; Miles, C..

    2014-01-01

    We examine the impact of chewing gum on a Bakan-type vigilance task that requires the continual updating of short-term order memory. Forty participants completed a 30-min auditory Bakan-task either with, or without, the requirement to chew gum. Self-rated measures of mood were taken both pre- and post-task. As expected, the vigilance task produced a time-dependent performance decrement indexed via decreases in target detections and lengthened correct reaction times (RTs), and a reduction in p...

  3. Estimation of Correlation Functions by Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune

    This paper illustrates how correlation functions can be estimated by the random decrement technique. Several different formulations of the random decrement technique, estimating the correlation functions are considered. The speed and accuracy of the different formulations of the random decrement...... and the length of the correlation functions. The accuracy of the estimates with respect to the theoretical correlation functions and the modal parameters are both investigated. The modal parameters are extracted from the correlation functions using the polyreference time domain technique....

  4. The role of memory representation in the vigilance decrement.

    Science.gov (United States)

    Caggiano, Daniel M; Parasuraman, Raja

    2004-10-01

    Working memory load is critically important for the overall level of performance on vigilance tasks. However, its role in a key aspect of vigilance-sensitivity decrement over time-is unclear. We used a dual-task procedure in which either a spatial or a nonspatial working memory task was performed simultaneously with a spatial vigilance task for 20 min. Sensitivity in the vigilance task declined over time when the concurrent task involved spatial working memory. In contrast, there was no sensitivity decrement with a nonspatial working memory task. The results provide the first evidence of a specific role for working memory representation in vigilance decrement. The findings are also consistent with a multiple resource theory in which separate resources for memory representation and cognitive control operations are differentially susceptible to depletion over time, depending on the demands of the task at hand.

  5. The reward-based eating drive scale: a self-report index of reward-based eating.

    Directory of Open Access Journals (Sweden)

    Elissa S Epel

    Full Text Available Why are some individuals more vulnerable to persistent weight gain and obesity than are others? Some obese individuals report factors that drive overeating, including lack of control, lack of satiation, and preoccupation with food, which may stem from reward-related neural circuitry. These are normative and common symptoms and not the sole focus of any existing measures. Many eating scales capture these common behaviors, but are confounded with aspects of dysregulated eating such as binge eating or emotional overeating. Across five studies, we developed items that capture this reward-based eating drive (RED. Study 1 developed the items in lean to obese individuals (n = 327 and examined changes in weight over eight years. In Study 2, the scale was further developed and expert raters evaluated the set of items. Study 3 tested psychometric properties of the final 9 items in 400 participants. Study 4 examined psychometric properties and race invariance (n = 80 women. Study 5 examined psychometric properties and age/gender invariance (n = 381. Results showed that RED scores correlated with BMI and predicted earlier onset of obesity, greater weight fluctuations, and greater overall weight gain over eight years. Expert ratings of RED scale items indicated that the items reflected characteristics of reward-based eating. The RED scale evidenced high internal consistency and invariance across demographic factors. The RED scale, designed to tap vulnerability to reward-based eating behavior, appears to be a useful brief tool for identifying those at higher risk of weight gain over time. Given the heterogeneity of obesity, unique brief profiling of the reward-based aspect of obesity using a self-report instrument such as the RED scale may be critical for customizing effective treatments in the general population.

  6. Application of Vector Triggering Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Ibrahim, S. R.; Brincker, Rune

    result is a Random Decrement function from each measurement. In traditional Random Decrement estimation the triggering condition is a scalar condition, which should only be fulfilled in a single measurement. In vector triggering Random Decrement the triggering condition is a vector condition......This paper deals with applications of the vector triggering Random Decrement technique. This technique is new and developed with the aim of minimizing estimation time and identification errors. The theory behind the technique is discussed in an accompanying paper. The results presented...... in this paper should be regarded as a further documentation of the technique. The key point in Random Decrement estimation is the formulation of a triggering condition. If the triggering condition is fulfilled a time segment from each measurement is picked out and averaged with previous time segments. The final...

  7. Application of Vector Triggering Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Ibrahim, S. R.; Brincker, Rune

    1997-01-01

    result is a Random Decrement function from each measurement. In traditional Random Decrement estimation the triggering condition is a scalar condition, which should only be fulfilled in a single measurement. In vector triggering Random Decrement the triggering condition is a vector condition......This paper deals with applications of the vector triggering Random Decrement technique. This technique is new and developed with the aim of minimizing estimation time and identification errors. The theory behind the technique is discussed in an accompanying paper. The results presented...... in this paper should be regarded as a further documentation of the technique. The key point in Random Decrement estimation is the formulation of a triggering condition. If the triggering condition is fulfilled a time segment from each measurement is picked out and averaged with previous time segments. The final...

  8. Chewing gum moderates the vigilance decrement.

    Science.gov (United States)

    Morgan, Kate; Johnson, Andrew J; Miles, Christopher

    2014-05-01

    We examine the impact of chewing gum on a Bakan-type vigilance task that requires the continual updating of short-term order memory. Forty participants completed a 30-min auditory Bakan-task either with, or without, the requirement to chew gum. Self-rated measures of mood were taken both pre- and post-task. As expected, the vigilance task produced a time-dependent performance decrement indexed via decreases in target detections and lengthened correct reaction times (RTs), and a reduction in post-task self-rated alertness scores. The declines in both performance and subjective alertness were attenuated in the chewing-gum group. In particular, correct RTs were significantly shorter following the chewing of gum in the latter stages of the task. Additionally, the gradients of decline for target detection and incline for correct RTs were both attenuated for the chewing-gum group. These findings are consistent with the data of Tucha and Simpson (2011), Appetite, 56, 299-301, who showed beneficial effects of chewing gum in the latter stages of a 30 min visual attention task, and extend their data to a task that necessitates the continuous updating of order memory. It is noteworthy that our data contradict the claim (Kozlov, Hughes, & Jones, 2012, Q. J. Exp. Psychology, 65, 501-513) that chewing gum negatively impacts short-term memory task performance. © 2013 The British Psychological Society.

  9. Neurocognitive decrements are present in intellectually superior schizophrenia

    Directory of Open Access Journals (Sweden)

    Anja eVaskinn

    2014-05-01

    Full Text Available Data suggests that individuals with schizophrenia (SZ and superior intelligence can present without specific neurocognitive deficits. However, neurocognitive decrements, defined as worse cognition than expected, have been reported in practically all schizophrenia cases. This study investigated if neurocognitive decrements are present in intellectually superior SZ by comparing the neuropsychological profile of SZ cases with IQ-matched healthy controls (HC across intellectual level. Participants with SZ and HCs were stratified into three IQ-groups; intellectually low (IQ 80-95; SZ n = 65 & HC n = 13, intellectually normal (IQ = 100-115; SZ n = 111 & HC n = 115 and intellectually superior (IQ > 120; SZ n = 20 & HC n = 50. A repeated measures multivariate analysis of co-variance compared performance on eight selected neuropsychological tests across IQ-strata and diagnostic group. Differences in clinical characteristics and social functioning in SZ across IQ-strata were investigated with multivariate and univariate analyses of variance. Intellectually superior SZ participants scored within normal limits, but had neurocognitive decrements compared to superior HCs. Decrements were of the same magnitude as in the low and normal IQ-strata. Levels of functional impairments and clinical characteristics in participants with SZ did not differ significantly across IQ-strata. Results indicate that neurocognitive decrements are present in intellectually superior SZ to the same extent as in intellectually low and intellectually normal SZ, supporting the notion that SZ is a neurocognitive disorder. Similar levels of social functional deficits and clinical symptoms suggest similar disease processes in SZ across intellectual level.

  10. The role of memory representation in the vigilance decrement

    OpenAIRE

    CAGGIANO, DANIEL M.; PARASURAMAN, RAJA

    2004-01-01

    Working memory load is critically important for the overall level of performance on vigilance tasks. However, its role in a key aspect of vigilance—sensitivity decrement over time—is unclear. We used a dual-task procedure in which either a spatial or a nonspatial working memory task was performed simultaneously with a spatial vigilance task for 20 min. Sensitivity in the vigilance task declined over time when the concurrent task involved spatial working memory. In contrast, there was no sensi...

  11. Financing Target and Resale Pricing in Reward-Based Crowdfunding

    Directory of Open Access Journals (Sweden)

    Lei Xu

    2018-04-01

    Full Text Available Resale is an effective tool for reward-based crowdfunding creators to make more profit after crowdfunding successfully. On the one hand, funds raised during the crowdfunding affect the resale pricing as a capital constraint; on the other hand, backers’ strategic purchasing behavior in the resale stage can also disturb the creator’s financing target decision-making through affecting resale pricing. In view of this, this paper builds a two-stage crowdfunding model to examine the interaction between the financing target and resale pricing in the presence of strategic backers. The results show that a lower financing amount leads to higher prices in the resale stage due to the rationing effect, and suppresses price volatility due to strategic purchasing behavior. In contrast, a higher financing amount enables the creator to build a large capacity, which does not restrict the resale prices and profit. Besides, in the context of high unit production cost or high backer patience level, there is no need for the creator to set a high financing target at the risk of crowdfunding failure.

  12. Profitable Nonprofits? Reward-Based Crowdfunding in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Makýšová Lucia

    2017-12-01

    Full Text Available This paper deals with crowdfunding as a new and alternative mechanism of nonprofit funding which has thus far attracted little scholarly attention in the Czech context. It focuses on the factors that affect a campaign’s overfunding rate and determines whether these factors are consistent among different forms of project creators. A comprehensive analysis of reward-based crowdfunding in the Czech Republic was conducted based on the data from 617 projects using the Czech crowdfunding platform Hithit that were categorized according to the status of the project creator. Using binary logistic regression, a statistic estimation on an overall sample and on a sample of purely nonprofit projects was executed in order to observe if the outcomes diff er. Th e key empirical finding is that NGOs tend to raise fewer additional funds than other forms of project creators. Except for certain specific factors, the effects of the examined factors were consistent across all samples. Th is new and innovative approach to resource insufficiency by using alternative funding sources presents an important and unexplored research gap in the (post- transitive context of nonprofit sector studies, enabling a view of policy implications for Czech NGOs.

  13. Identification of System Parameters by the Random Decrement Technique

    DEFF Research Database (Denmark)

    Brincker, Rune; Kirkegaard, Poul Henning; Rytter, Anders

    -Walker equations and finally least square fitting of the theoretical correlation function. The results are compared to the results of fitting an Auto Regressive Moving Average(ARMA) model directly to the system output. All investigations are performed on the simulated output from a single degree-off-freedom system......The aim of this paper is to investigate and illustrate the possibilities of using correlation functions estimated by the Random Decrement Technique as a basis for parameter identification. A two-stage system identification method is used: first the correlation functions are estimated by the Random...... Decrement technique and then the system parameters are identified from the correlation function estimates. Three different techniques are used in the parameters identification process: a simple non-paramatic method, estimation of an Auto Regressive(AR) model by solving an overdetermined set of Yule...

  14. A new semantic vigilance task: vigilance decrement, workload, and sensitivity to dual-task costs.

    Science.gov (United States)

    Epling, Samantha L; Russell, Paul N; Helton, William S

    2016-01-01

    Cognitive resource theory is a common explanation for both the performance decline in vigilance tasks, known as the vigilance decrement, and the limited ability to perform multiple tasks simultaneously. The limited supply of cognitive resources may be utilized faster than they are replenished resulting in a performance decrement, or may need to be allocated among multiple tasks with some performance cost. Researchers have proposed both domain-specific, for example spatial versus verbal processing resources, and domain general cognitive resources. One challenge in testing the domain specificity of cognitive resources in vigilance is the current lack of difficult semantic vigilance tasks which reliably produce a decrement. In the present research, we investigated whether the vigilance decrement was found in a new abbreviated semantic discrimination vigilance task, and whether there was a performance decrement in said vigilance task when paired with a word recall task, as opposed to performed individually. As hypothesized, a vigilance decrement in the semantic vigilance task was found in both the single-task and dual-task conditions, along with reduced vigilance performance in the dual-task condition and reduced word recall in the dual-task condition. This is consistent with cognitive resource theory. The abbreviated semantic vigilance task will be a useful tool for researchers interested in determining the specificity of cognitive resources utilized in vigilance tasks.

  15. An Effective Privacy Architecture to Preserve User Trajectories in Reward-Based LBS Applications

    Directory of Open Access Journals (Sweden)

    A S M Touhidul Hasan

    2018-02-01

    Full Text Available How can training performance data (e.g., running or walking routes be collected, measured, and published in a mobile program while preserving user privacy? This question is becoming important in the context of the growing use of reward-based location-based service (LBS applications, which aim to promote employee training activities and to share such data with insurance companies in order to reduce the healthcare insurance costs of an organization. One of the main concerns of such applications is the privacy of user trajectories, because the applications normally collect user locations over time with identities. The leak of the identified trajectories often results in personal privacy breaches. For instance, a trajectory would expose user interest in places and behaviors in time by inference and linking attacks. This information can be used for spam advertisements or individual-based assaults. To the best of our knowledge, no existing studies can be directly applied to solve the problem while keeping data utility. In this paper, we identify the personal privacy problem in a reward-based LBS application and propose privacy architecture with a bounded perturbation technique to protect user’s trajectory from the privacy breaches. Bounded perturbation uses global location set (GLS to anonymize the trajectory data. In addition, the bounded perturbation will not generate any visiting points that are not possible to visit in real time. The experimental results on real-world datasets demonstrate that the proposed bounded perturbation can effectively anonymize location information while preserving data utility compared to the existing methods.

  16. State-based versus reward-based motivation in younger and older adults.

    Science.gov (United States)

    Worthy, Darrell A; Cooper, Jessica A; Byrne, Kaileigh A; Gorlick, Marissa A; Maddox, W Todd

    2014-12-01

    Recent decision-making work has focused on a distinction between a habitual, model-free neural system that is motivated toward actions that lead directly to reward and a more computationally demanding goal-directed, model-based system that is motivated toward actions that improve one's future state. In this article, we examine how aging affects motivation toward reward-based versus state-based decision making. Participants performed tasks in which one type of option provided larger immediate rewards but the alternative type of option led to larger rewards on future trials, or improvements in state. We predicted that older adults would show a reduced preference for choices that led to improvements in state and a greater preference for choices that maximized immediate reward. We also predicted that fits from a hybrid reinforcement-learning model would indicate greater model-based strategy use in younger than in older adults. In line with these predictions, older adults selected the options that maximized reward more often than did younger adults in three of the four tasks, and modeling results suggested reduced model-based strategy use. In the task where older adults showed similar behavior to younger adults, our model-fitting results suggested that this was due to the utilization of a win-stay-lose-shift heuristic rather than a more complex model-based strategy. Additionally, within older adults, we found that model-based strategy use was positively correlated with memory measures from our neuropsychological test battery. We suggest that this shift from state-based to reward-based motivation may be due to age related declines in the neural structures needed for more computationally demanding model-based decision making.

  17. External Goal Setting in Reward-Based Crowdfunding - Inventor, Marathoner, Sprinter and Extreme Sprinter

    OpenAIRE

    Haug, Jonas; Haslum, Mikkel Hilde

    2016-01-01

    Purpose In recent years, crowdfunding has emerged as a popular method to finance entrepreneurial ventures. Entrepreneurs appeal directly to the general public, e.g. the crowd, for help getting their innovative ideas off the ground. Within the world of reward-based crowdfunding, the authors of how to -literature (practitioners) and the authors of theoretical reward-based crowdfunding literature (theoreticians) disagree on strategies for setting the external (i.e. public) funding goal. ...

  18. Statistical Theory of the Vector Random Decrement Technique

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune; Ibrahim, S. R.

    1999-01-01

    decays. Due to the speed and/or accuracy of the Vector Random Decrement technique, it was introduced as an attractive alternative to the Random Decrement technique. In this paper, the theory of the Vector Random Decrement technique is extended by applying a statistical description of the stochastic...

  19. The cognitive effects and decrements following concussion

    Directory of Open Access Journals (Sweden)

    Tracey Covassin

    2010-05-01

    Full Text Available Tracey Covassin, Robert J ElbinMichigan State University, Department of Kinesiology, East Lansing, MI, USAAbstract: Sports-related concussion is an injury that continues to receive attention from both the popular media and sports medicine community. The many different symptom presentations and cognitive decrements that follow concussions, have made this injury difficult to detect and manage. Furthermore, concussed athletes should not always be entrusted to appropriately self-report their concussion symptoms; therefore the burden falls on the clinician and coach. Recent management recommendations call for using a multi-faceted approach to managing concussion, which consists of neurocognitive testing before (ie, baseline/preseason and after injury. In addition age, sex, and previous history of concussion have been found to influence the risk and recovery from this injury.Keywords: cognitive function, neurocognitive testing, concussion

  20. Ambient Modal Testing of the Vestvej Bridge using Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune; Rytter, A.

    This paper presents an ambient vibration study of the Vestvej Bridge. The bridge is a typically Danish two-span concrete bridge which crosses a highway. The purpose of the study is to perform a pre-investigation of the dynamic behavior to obtain information for the design of a demonstration project...... concerning application of vibration based inspection of bridges. The data analysis process of ambient vribration testing of bridges has traditionally been based on auto and cross spectral densities estimated using an FFT algorithm. In the pre-analysis state the spectral densities are all averaged to obtain...... measurements might have a low signal to noise ratio. Thus, it might be difficult clearly to identify physical modes from the spectral densities. The Random Decrement (RD) technique is another method to perform the data analysis process in the time domain only. It is basically a very simple and very easily...

  1. Ambient Modal Testing of the Vestvej Bridge using Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune; Rytter, A.

    1998-01-01

    This paper presents an ambient vibration study of the Vestvej Bridge. The bridge is a typically Danish two-span concrete bridge which crosses a highway. The purpose of the study is to perform a pre-investigation of the dynamic behavior to obtain information for the design of a demonstration project...... concerning application of vibration based inspection of bridges. The data analysis process of ambient vribration testing of bridges has traditionally been based on auto and cross spectral densities estimated using an FFT algorithm. In the pre-analysis state the spectral densities are all averaged to obtain...... measurements might have a low signal to noise ratio. Thus, it might be difficult clearly to identify physical modes from the spectral densities. The Random Decrement (RD) technique is another method to perform the data analysis process in the time domain only. It is basically a very simple and very easily...

  2. Neural correlates of reward-based spatial learning in persons with cocaine dependence.

    Science.gov (United States)

    Tau, Gregory Z; Marsh, Rachel; Wang, Zhishun; Torres-Sanchez, Tania; Graniello, Barbara; Hao, Xuejun; Xu, Dongrong; Packard, Mark G; Duan, Yunsuo; Kangarlu, Alayar; Martinez, Diana; Peterson, Bradley S

    2014-02-01

    Dysfunctional learning systems are thought to be central to the pathogenesis of and impair recovery from addictions. The functioning of the brain circuits for episodic memory or learning that support goal-directed behavior has not been studied previously in persons with cocaine dependence (CD). Thirteen abstinent CD and 13 healthy participants underwent MRI scanning while performing a task that requires the use of spatial cues to navigate a virtual-reality environment and find monetary rewards, allowing the functional assessment of the brain systems for spatial learning, a form of episodic memory. Whereas both groups performed similarly on the reward-based spatial learning task, we identified disturbances in brain regions involved in learning and reward in CD participants. In particular, CD was associated with impaired functioning of medial temporal lobe (MTL), a brain region that is crucial for spatial learning (and episodic memory) with concomitant recruitment of striatum (which normally participates in stimulus-response, or habit, learning), and prefrontal cortex. CD was also associated with enhanced sensitivity of the ventral striatum to unexpected rewards but not to expected rewards earned during spatial learning. We provide evidence that spatial learning in CD is characterized by disturbances in functioning of an MTL-based system for episodic memory and a striatum-based system for stimulus-response learning and reward. We have found additional abnormalities in distributed cortical regions. Consistent with findings from animal studies, we provide the first evidence in humans describing the disruptive effects of cocaine on the coordinated functioning of multiple neural systems for learning and memory.

  3. Vascular Risk Factors and Diseases Modulate Deficits of Reward-Based Reversal Learning in Acute Basal Ganglia Stroke.

    Directory of Open Access Journals (Sweden)

    Ulla K Seidel

    Full Text Available Besides motor function, the basal ganglia have been implicated in feedback learning. In patients with chronic basal ganglia infarcts, deficits in reward-based reversal learning have previously been described.We re-examined the acquisition and reversal of stimulus-stimulus-reward associations and acquired equivalence in eleven patients with acute basal ganglia stroke (8 men, 3 women; 57.8±13.3 years, whose performance was compared eleven healthy subjects of comparable age, sex distribution and education, who were recruited outside the hospital. Eleven hospitalized patients with a similar vascular risk profile as the stroke patients but without stroke history served as clinical control group.In a neuropsychological assessment 7±3 days post-stroke, verbal and spatial short-term and working memory and inhibition control did not differ between groups. Compared with healthy subjects, control patients with vascular risk factors exhibited significantly reduced performance in the reversal phase (F[2,30] = 3.47; p = 0.044; post-hoc comparison between risk factor controls and healthy controls: p = 0.030, but not the acquisition phase (F[2,30] = 1.01; p = 0.376 and the acquired equivalence (F[2,30] = 1.04; p = 0.367 tasks. In all tasks, the performance of vascular risk factor patients closely resembled that of basal ganglia stroke patients. Correlation studies revealed a significant association of the number of vascular risk factors with reversal learning (r = -0.33, p = 0.012, but not acquisition learning (r = -0.20, p = 0.121 or acquired equivalence (r = -0.22, p = 0.096.The previously reported impairment of reward-based learning may be attributed to vascular risk factors and associated diseases, which are enriched in stroke patients. This study emphasizes the necessity of appropriate control subjects in cognition studies.

  4. Reward-based spatial learning in unmedicated adults with obsessive-compulsive disorder.

    Science.gov (United States)

    Marsh, Rachel; Tau, Gregory Z; Wang, Zhishun; Huo, Yuankai; Liu, Ge; Hao, Xuejun; Packard, Mark G; Peterson, Bradley S; Simpson, H Blair

    2015-04-01

    The authors assessed the functioning of mesolimbic and striatal areas involved in reward-based spatial learning in unmedicated adults with obsessive-compulsive disorder (OCD). Functional MRI blood-oxygen-level-dependent response was compared in 33 unmedicated adults with OCD and 33 healthy, age-matched comparison subjects during a reward-based learning task that required learning to use extramaze cues to navigate a virtual eight-arm radial maze to find hidden rewards. The groups were compared in their patterns of brain activation associated with reward-based spatial learning versus a control condition in which rewards were unexpected because they were allotted pseudorandomly to experimentally prevent learning. Both groups learned to navigate the maze to find hidden rewards, but group differences in neural activity during navigation and reward processing were detected in mesolimbic and striatal areas. During navigation, the OCD group, unlike the healthy comparison group, exhibited activation in the left posterior hippocampus. Unlike healthy subjects, participants in the OCD group did not show activation in the left ventral putamen and amygdala when anticipating rewards or in the left hippocampus, amygdala, and ventral putamen when receiving unexpected rewards (control condition). Signal in these regions decreased relative to baseline during unexpected reward receipt among those in the OCD group, and the degree of activation was inversely associated with doubt/checking symptoms. Participants in the OCD group displayed abnormal recruitment of mesolimbic and ventral striatal circuitry during reward-based spatial learning. Whereas healthy comparison subjects exhibited activation in this circuitry in response to the violation of reward expectations, unmedicated OCD participants did not and instead over-relied on the posterior hippocampus during learning. Thus, dopaminergic innervation of reward circuitry may be altered, and future study of anterior/posterior hippocampal

  5. Modelling comonotonic group-life under dependent decrement causes

    OpenAIRE

    Wang, Dabuxilatu

    2011-01-01

    Comonotonicity had been a extreme case of dependency between random variables. This article consider an extension of single life model under multiple dependent decrement causes to the case of comonotonic group-life.

  6. Challenges in the Detection of Working Memory and Attention Decrements among Overweight Adolescent Girls.

    Science.gov (United States)

    Bauer, Lance O; Manning, Kevin J

    2016-01-01

    The present study is unique in employing unusually difficult attention and working memory tasks to reveal subtle cognitive decrements among overweight/obese adolescents. It evaluated novel measures of background electroencephalographic (EEG) activity during one of the tasks and tested correlations of these and other measures with psychological and psychiatric predictors of obesity maintenance or progression. Working memory and sustained attention tasks were presented to 158 female adolescents who were rated on dichotomous (body mass index percentile working memory task. During the sustained attention task, overweight/obese adolescents exhibited more EEG frontal beta power as well as greater intraindividual variability in reaction time and beta power across task periods than their normal-weight peers. Secondary analyses showed that frontal beta power during the sustained attention task was positively correlated with anxiety, panic, borderline personality features, drug abuse, and loss of control over food intake. The findings suggest that working memory and sustained attention decrements do exist among overweight/obese adolescent girls. The reliable detection of the decrements may depend on the difficulty of the tasks as well as the manner in which performance and brain activity are measured. Future studies should examine the relevance of these decrements to dietary education efforts and treatment response. © 2016 S. Karger AG, Basel.

  7. Model Seleksi Premi Asuransi Jiwa Dwiguna untuk Kasus Multiple Decrement

    OpenAIRE

    Cita, Devi Ramana; Pane, Rolan; ', Harison

    2015-01-01

    This article discusses a select survival model for the case of multiple decrements in evaluating endowment life insurance premium for person currently aged ( + ) years, who is selected at age with ℎ years selection period. The case of multiple decrements in this case is limited to two cases. The calculation of the annual premium is done by prior evaluating of the single premium, and the present value of annuity depends on theconstant force assumption.

  8. OXYGEN UPTAKE KINETICS DURING INCREMENTAL- AND DECREMENTAL-RAMP CYCLE ERGOMETRY

    Directory of Open Access Journals (Sweden)

    Fadıl Özyener

    2011-09-01

    Full Text Available The pulmonary oxygen uptake (VO2 response to incremental-ramp cycle ergometry typically demonstrates lagged-linear first-order kinetics with a slope of ~10-11 ml·min-1·W-1, both above and below the lactate threshold (ӨL, i.e. there is no discernible VO2 slow component (or "excess" VO2 above ӨL. We were interested in determining whether a reverse ramp profile would yield the same response dynamics. Ten healthy males performed a maximum incremental -ramp (15-30 W·min-1, depending on fitness. On another day, the work rate (WR was increased abruptly to the incremental maximum and then decremented at the same rate of 15-30 W.min-1 (step-decremental ramp. Five subjects also performed a sub-maximal ramp-decremental test from 90% of ӨL. VO2 was determined breath-by-breath from continuous monitoring of respired volumes (turbine and gas concentrations (mass spectrometer. The incremental-ramp VO2-WR slope was 10.3 ± 0.7 ml·min-1·W-1, whereas that of the descending limb of the decremental ramp was 14.2 ± 1.1 ml·min-1·W-1 (p < 0.005. The sub-maximal decremental-ramp slope, however, was only 9. 8 ± 0.9 ml·min-1·W-1: not significantly different from that of the incremental-ramp. This suggests that the VO2 response in the supra-ӨL domain of incremental-ramp exercise manifest not actual, but pseudo, first-order kinetics

  9. Modal Analysis Based on the Random Decrement Transform

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune; Ibrahim, S. R.

    of this paper is to present a state-of-the-art description of the Random Decrement technique where the statistical theory is outlined and examples are given. But also new results such as estimation of frequency response functions and quality assessment are introduced. Special attention is given......During the last years several papers utilizing the Random Decrement transform as a basis for extraction of modal parameters from the response of linear systems subjected to unknown ambient loads have been presented. Although the Random Decrement technique was developed in a decade starting from...... the introduktion in 1968 the technique seems still to be attractive. This is probably due to the simplicity and the speed of the algorithm and the fact that the theory of the technique has been extended by introducing statistical measures such as correlation functions or spectral densities. The purpose...

  10. Two spatiotemporally distinct value systems shape reward-based learning in the human brain.

    Science.gov (United States)

    Fouragnan, Elsa; Retzler, Chris; Mullinger, Karen; Philiastides, Marios G

    2015-09-08

    Avoiding repeated mistakes and learning to reinforce rewarding decisions is critical for human survival and adaptive actions. Yet, the neural underpinnings of the value systems that encode different decision-outcomes remain elusive. Here coupling single-trial electroencephalography with simultaneously acquired functional magnetic resonance imaging, we uncover the spatiotemporal dynamics of two separate but interacting value systems encoding decision-outcomes. Consistent with a role in regulating alertness and switching behaviours, an early system is activated only by negative outcomes and engages arousal-related and motor-preparatory brain structures. Consistent with a role in reward-based learning, a later system differentially suppresses or activates regions of the human reward network in response to negative and positive outcomes, respectively. Following negative outcomes, the early system interacts and downregulates the late system, through a thalamic interaction with the ventral striatum. Critically, the strength of this coupling predicts participants' switching behaviour and avoidance learning, directly implicating the thalamostriatal pathway in reward-based learning.

  11. Motion-Induced Blindness Using Increments and Decrements of Luminance

    Directory of Open Access Journals (Sweden)

    Stine Wm Wren

    2017-10-01

    Full Text Available Motion-induced blindness describes the disappearance of stationary elements of a scene when other, perhaps non-overlapping, elements of the scene are in motion. We measured the effects of increment (200.0 cd/m2 and decrement targets (15.0 cd/m2 and masks presented on a grey background (108.0 cd/m2, tapping into putative ON- and OFF-channels, on the rate of target disappearance psychophysically. We presented two-frame motion, which has coherent motion energy, and dynamic Glass patterns and dynamic anti-Glass patterns, which do not have coherent motion energy. Using the method of constant stimuli, participants viewed stimuli of varying durations (3.1 s, 4.6 s, 7.0 s, 11 s, or 16 s in a given trial and then indicated whether or not the targets vanished during that trial. Psychometric function midpoints were used to define absolute threshold mask duration for the disappearance of the target. 95% confidence intervals for threshold disappearance times were estimated using a bootstrap technique for each of the participants across two experiments. Decrement masks were more effective than increment masks with increment targets. Increment targets were easier to mask than decrement targets. Distinct mask pattern types had no effect, suggesting that perceived coherence contributes to the effectiveness of the mask. The ON/OFF dichotomy clearly carries its influence to the level of perceived motion coherence. Further, the asymmetry in the effects of increment and decrement masks on increment and decrement targets might lead one to speculate that they reflect the ‘importance’ of detecting decrements in the environment.

  12. A Dynamic Connectome Supports the Emergence of Stable Computational Function of Neural Circuits through Reward-Based Learning.

    Science.gov (United States)

    Kappel, David; Legenstein, Robert; Habenschuss, Stefan; Hsieh, Michael; Maass, Wolfgang

    2018-01-01

    Synaptic connections between neurons in the brain are dynamic because of continuously ongoing spine dynamics, axonal sprouting, and other processes. In fact, it was recently shown that the spontaneous synapse-autonomous component of spine dynamics is at least as large as the component that depends on the history of pre- and postsynaptic neural activity. These data are inconsistent with common models for network plasticity and raise the following questions: how can neural circuits maintain a stable computational function in spite of these continuously ongoing processes, and what could be functional uses of these ongoing processes? Here, we present a rigorous theoretical framework for these seemingly stochastic spine dynamics and rewiring processes in the context of reward-based learning tasks. We show that spontaneous synapse-autonomous processes, in combination with reward signals such as dopamine, can explain the capability of networks of neurons in the brain to configure themselves for specific computational tasks, and to compensate automatically for later changes in the network or task. Furthermore, we show theoretically and through computer simulations that stable computational performance is compatible with continuously ongoing synapse-autonomous changes. After reaching good computational performance it causes primarily a slow drift of network architecture and dynamics in task-irrelevant dimensions, as observed for neural activity in motor cortex and other areas. On the more abstract level of reinforcement learning the resulting model gives rise to an understanding of reward-driven network plasticity as continuous sampling of network configurations.

  13. Advances in Computational High-Resolution Mechanical Spectroscopy HRMS Part I: Logarithmic Decrement

    International Nuclear Information System (INIS)

    Majewski, M; Magalas, L B; Piłat, A

    2012-01-01

    The comparison between different methods used to compute the logarithmic decrement in high-resolution mechanical spectroscopy (HRMS) is analyzed. The performance of parametric OMI method (Optimization in Multiple Intervals) and interpolated discrete Fourier transform (IpDFT) methods are investigated as a function of the sampling frequency used to digitize free decaying oscillations in low-frequency resonant mechanical spectrometers. It is clearly demonstrated that a new Yoshida-Magalas (YM) method is the most powerful IpDFT-based method which outperforms the standard Yoshida (Y) method and other DFT-based methods. Four IpDFT methods and the OMI method are carefully analyzed as a function of the sampling frequency. The results presented in this work clearly show that the relative error in the estimation of the logarithmic decrement depends both on the length of free decaying signal and on the sampling frequency. The effect of the sampling frequency was not yet reported in the literature. The performance of different methods used in the computations of the logarithmic decrement can be listed in the following order: (1) the OMI, (2) the Yoshida-Magalas YM, (3) the Yoshida-Magalas YMC, and finally (4) the Yoshida Y.

  14. Reinforcement learning signals in the human striatum distinguish learners from nonlearners during reward-based decision making.

    Science.gov (United States)

    Schönberg, Tom; Daw, Nathaniel D; Joel, Daphna; O'Doherty, John P

    2007-11-21

    The computational framework of reinforcement learning has been used to forward our understanding of the neural mechanisms underlying reward learning and decision-making behavior. It is known that humans vary widely in their performance in decision-making tasks. Here, we used a simple four-armed bandit task in which subjects are almost evenly split into two groups on the basis of their performance: those who do learn to favor choice of the optimal action and those who do not. Using models of reinforcement learning we sought to determine the neural basis of these intrinsic differences in performance by scanning both groups with functional magnetic resonance imaging. We scanned 29 subjects while they performed the reward-based decision-making task. Our results suggest that these two groups differ markedly in the degree to which reinforcement learning signals in the striatum are engaged during task performance. While the learners showed robust prediction error signals in both the ventral and dorsal striatum during learning, the nonlearner group showed a marked absence of such signals. Moreover, the magnitude of prediction error signals in a region of dorsal striatum correlated significantly with a measure of behavioral performance across all subjects. These findings support a crucial role of prediction error signals, likely originating from dopaminergic midbrain neurons, in enabling learning of action selection preferences on the basis of obtained rewards. Thus, spontaneously observed individual differences in decision making performance demonstrate the suggested dependence of this type of learning on the functional integrity of the dopaminergic striatal system in humans.

  15. Impaired Flexible Reward-Based Decision-Making in Binge Eating Disorder: Evidence from Computational Modeling and Functional Neuroimaging.

    Science.gov (United States)

    Reiter, Andrea M F; Heinze, Hans-Jochen; Schlagenhauf, Florian; Deserno, Lorenz

    2017-02-01

    Despite its clinical relevance and the recent recognition as a diagnostic category in the DSM-5, binge eating disorder (BED) has rarely been investigated from a cognitive neuroscientific perspective targeting a more precise neurocognitive profiling of the disorder. BED patients suffer from a lack of behavioral control during recurrent binge eating episodes and thus fail to adapt their behavior in the face of negative consequences, eg, high risk for obesity. To examine impairments in flexible reward-based decision-making, we exposed BED patients (n=22) and matched healthy individuals (n=22) to a reward-guided decision-making task during functional resonance imaging (fMRI). Performing fMRI analysis informed via computational modeling of choice behavior, we were able to identify specific signatures of altered decision-making in BED. On the behavioral level, we observed impaired behavioral adaptation in BED, which was due to enhanced switching behavior, a putative deficit in striking a balance between exploration and exploitation appropriately. This was accompanied by diminished activation related to exploratory decisions in the anterior insula/ventro-lateral prefrontal cortex. Moreover, although so-called model-free reward prediction errors remained intact, representation of ventro-medial prefrontal learning signatures, incorporating inference on unchosen options, was reduced in BED, which was associated with successful decision-making in the task. On the basis of a computational psychiatry account, the presented findings contribute to defining a neurocognitive phenotype of BED.

  16. Random Decrement and Regression Analysis of Traffic Responses of Bridges

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Ibrahim, S. R.; Brincker, Rune

    1996-01-01

    The topic of this paper is the estimation of modal parameters from ambient data by applying the Random Decrement technique. The data fro the Queensborough Bridge over the Fraser River in Vancouver, Canada have been applied. The loads producing the dynamic response are ambient, e. g. wind, traffic...

  17. Random Decrement and Regression Analysis of Traffic Responses of Bridges

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Ibrahim, S. R.; Brincker, Rune

    The topic of this paper is the estimation of modal parameters from ambient data by applying the Random Decrement technique. The data from the Queensborough Bridge over the Fraser River in Vancouver, Canada have been applied. The loads producing the dynamic response are ambient, e.g. wind, traffic...

  18. Vector Triggering Random Decrement for High Identification Accuracy

    DEFF Research Database (Denmark)

    Ibrahim, S. R.; Asmussen, J. C.; Brincker, Rune

    Using the Random Decrement (RD) technique to obtain free response estimates and combining this with time domain modal identification methods to obtain the poles and the mode shapes is acknowledged as a fast and accurate way of analysing measured responses of structures subject to ambient loads. W...

  19. Response-only modal identification using random decrement algorithm with time-varying threshold level

    International Nuclear Information System (INIS)

    Lin, Chang Sheng; Tseng, Tse Chuan

    2014-01-01

    Modal Identification from response data only is studied for structural systems under nonstationary ambient vibration. The topic of this paper is the estimation of modal parameters from nonstationary ambient vibration data by applying the random decrement algorithm with time-varying threshold level. In the conventional random decrement algorithm, the threshold level for evaluating random dec signatures is defined as the standard deviation value of response data of the reference channel. The distortion of random dec signatures may be, however, induced by the error involved in noise from the original response data in practice. To improve the accuracy of identification, a modification of the sampling procedure in random decrement algorithm is proposed for modal-parameter identification from the nonstationary ambient response data. The time-varying threshold level is presented for the acquisition of available sample time history to perform averaging analysis, and defined as the temporal root-mean-square function of structural response, which can appropriately describe a wide variety of nonstationary behaviors in reality, such as the time-varying amplitude (variance) of a nonstationary process in a seismic record. Numerical simulations confirm the validity and robustness of the proposed modal-identification method from nonstationary ambient response data under noisy conditions.

  20. Reward-based training of recurrent neural networks for cognitive and value-based tasks.

    Science.gov (United States)

    Song, H Francis; Yang, Guangyu R; Wang, Xiao-Jing

    2017-01-13

    Trained neural network models, which exhibit features of neural activity recorded from behaving animals, may provide insights into the circuit mechanisms of cognitive functions through systematic analysis of network activity and connectivity. However, in contrast to the graded error signals commonly used to train networks through supervised learning, animals learn from reward feedback on definite actions through reinforcement learning. Reward maximization is particularly relevant when optimal behavior depends on an animal's internal judgment of confidence or subjective preferences. Here, we implement reward-based training of recurrent neural networks in which a value network guides learning by using the activity of the decision network to predict future reward. We show that such models capture behavioral and electrophysiological findings from well-known experimental paradigms. Our work provides a unified framework for investigating diverse cognitive and value-based computations, and predicts a role for value representation that is essential for learning, but not executing, a task.

  1. Effects of frequency and duration on psychometric functions for detection of increments and decrements in sinusoids in noise.

    Science.gov (United States)

    Moore, B C; Peters, R W; Glasberg, B R

    1999-12-01

    Psychometric functions for detecting increments or decrements in level of sinusoidal pedestals were measured for increment and decrement durations of 5, 10, 20, 50, 100, and 200 ms and for frequencies of 250, 1000, and 4000 Hz. The sinusoids were presented in background noise intended to mask spectral splatter. A three-interval, three-alternative procedure was used. The results indicated that, for increments, the detectability index d' was approximately proportional to delta I/I. For decrements, d' was approximately proportional to delta L. The slopes of the psychometric functions increased (indicating better performance) with increasing frequency for both increments and decrements. For increments, the slopes increased with increasing increment duration up to 200 ms at 250 and 1000 Hz, but at 4000 Hz they increased only up to 50 ms. For decrements, the slopes increased for durations up to 50 ms, and then remained roughly constant, for all frequencies. For a center frequency of 250 Hz, the slopes of the psychometric functions for increment detection increased with duration more rapidly than predicted by a "multiple-looks" hypothesis, i.e., more rapidly than the square root of duration, for durations up to 50 ms. For center frequencies of 1000 and 4000 Hz, the slopes increased less rapidly than predicted by a multiple-looks hypothesis, for durations greater than about 20 ms. The slopes of the psychometric functions for decrement detection increased with decrement duration at a rate slightly greater than the square root of duration, for durations up to 50 ms, at all three frequencies. For greater durations, the increase in slope was less than proportional to the square root of duration. The results were analyzed using a model incorporating a simulated auditory filter, a compressive nonlinearity, a sliding temporal integrator, and a decision device based on a template mechanism. The model took into account the effects of both the external noise and an assumed internal

  2. Identification of System Parameters by the Random Decrement Technique

    DEFF Research Database (Denmark)

    Brincker, Rune; Kirkegaard, Poul Henning; Rytter, Anders

    1991-01-01

    -Walker equations and finally, least-square fitting of the theoretical correlation function. The results are compared to the results of fitting an Auto Regressive Moving Average (ARMA) model directly to the system output from a single-degree-of-freedom system loaded by white noise.......The aim of this paper is to investigate and illustrate the possibilities of using correlation functions estimated by the Random Decrement Technique as a basis for parameter identification. A two-stage system identification system is used: first, the correlation functions are estimated by the Random...... Decrement Technique, and then the system parameters are identified from the correlation function estimates. Three different techniques are used in the parameter identification process: a simple non-parametric method, estimation of an Auto Regressive (AR) model by solving an overdetermined set of Yule...

  3. Deep brain stimulation of the subthalamic nucleus improves reward-based decision-learning in Parkinson's disease

    NARCIS (Netherlands)

    van Wouwe, N.C.; Ridderinkhof, K.R.; van den Wildenberg, W.P.M.; Band, G.P.H.; Abisogun, A.; Elias, W.J.; Frysinger, R.; Wylie, S.A.

    2011-01-01

    Recently, the subthalamic nucleus (STN) has been shown to be critically involved in decision-making, action selection, and motor control. Here we investigate the effect of deep brain stimulation (DBS) of the STN on reward-based decision-learning in patients diagnosed with Parkinson's disease (PD).

  4. Deep brain stimulation of the subthalamic nucleus improves reward-based decision-learning in Parkinson’s disease

    NARCIS (Netherlands)

    Wouwe, N.C. van; Ridderinkhof, K.R.; Wildenberg, W.P.M. van den; Band, G.P.H.; Abisogun, A.; Elias, W.J.; Frysinger, R.; Wylie, S.A.

    2011-01-01

    Recently, the subthalamic nucleus (STN) has been shown to be critically involved in decision-making, action selection, and motor control. Here we investigate the effect of deep brain stimulation (DBS) of the STN on reward-based decision-learning in patients diagnosed with Parkinson’s disease (PD).

  5. Methodological issues underlying multiple decrement life table analysis.

    Science.gov (United States)

    Mode, C J; Avery, R C; Littman, G S; Potter, R G

    1977-02-01

    In this paper, the actuarial method of multiple decrement life table analysis of censored, longitudinal data is examined. The discussion is organized in terms of the first segment of usage of an intrauterine device. Weaknesses of the actuarial approach are pointed out, and an alternative approach, based on the classical model of competing risks, is proposed. Finally, the actuarial and the alternative method of analyzing censored data are compared, using data from the Taichung Medical Study on Intrauterine Devices.

  6. Baseline frontostriatal-limbic connectivity predicts reward-based memory formation.

    Science.gov (United States)

    Hamann, Janne M; Dayan, Eran; Hummel, Friedhelm C; Cohen, Leonardo G

    2014-12-01

    Reward mediates the acquisition and long-term retention of procedural skills in humans. Yet, learning under rewarded conditions is highly variable across individuals and the mechanisms that determine interindividual variability in rewarded learning are not known. We postulated that baseline functional connectivity in a large-scale frontostriatal-limbic network could predict subsequent interindividual variability in rewarded learning. Resting-state functional MRI was acquired in two groups of subjects (n = 30) who then trained on a visuomotor procedural learning task with or without reward feedback. We then tested whether baseline functional connectivity within the frontostriatal-limbic network predicted memory strength measured immediately, 24 h and 1 month after training in both groups. We found that connectivity in the frontostriatal-limbic network predicted interindividual variability in the rewarded but not in the unrewarded learning group. Prediction was strongest for long-term memory. Similar links between connectivity and reward-based memory were absent in two control networks, a fronto-parieto-temporal language network and the dorsal attention network. The results indicate that baseline functional connectivity within the frontostriatal-limbic network successfully predicts long-term retention of rewarded learning. © 2014 Wiley Periodicals, Inc.

  7. Reward-based behaviors and emotional processing in human with narcolepsy-cataplexy

    Directory of Open Access Journals (Sweden)

    Sophie eBayard

    2013-05-01

    Full Text Available ajor advances in the past decade have led a better understanding of the pathophysiology of narcolepsy with cataplexy caused by the early loss of hypothalamic hypocretin neurons. Although a role for hypocretin in the regulation of sleep/wakefulness state is widely recognized, other functions, not necessarily related to arousal, have been identified. Hence, the hypocretin system enhances signaling in the mesolimbic pathways regulating reward processing, emotion and mood regulation, and addiction. Although studies on hypocretin-deficient mice have shown that hypocretin plays an essential role in reward-seeking, depression-like behavior and addiction, results in human narcolepsy remained subject to debate. Most of studies revealed that hypocretin-deficient narcolepsy patients either drug-free or medicated with psychostimulant had preferences towards risky choices in a decision-making task under ambiguity together with higher frequency of depressive symptoms and binge eating disorder compared to controls. However, human studies mostly reported the lack of association with pathological impulsivity and gambling, and substance and alcohol abuse in the context of narcolepsy-cataplexy. Prospective larger studies are required to confirm these findings in drug-free and medicated patients with narcolepsy. Inclusion of patients with other central hypersomnias without hypocretin deficiency will provide answer to the major question of the role of the hypocretin system in reward-based behaviors and emotional processing in humans.

  8. Impact of a Rewards-Based Incentive Program on Promoting Fruit and Vegetable Purchases

    Science.gov (United States)

    Phipps, Etienne J.; Braitman, Leonard E.; Stites, Shana D.; Singletary, S. Brook; Wallace, Samantha L.; Hunt, Lacy; Axelrod, Saul; Glanz, Karen; Uplinger, Nadine

    2015-01-01

    Objectives. We assessed the impact of a rewards-based incentive program on fruit and vegetable purchases by low-income families. Methods. We conducted a 4-phase prospective cohort study with randomized intervention and wait-listed control groups in Philadelphia, Pennsylvania, in December 2010 through October 2011. The intervention provided a rebate of 50% of the dollar amount spent on fresh or frozen fruit and vegetables, reduced to 25% during a tapering phase, then eliminated. Primary outcome measures were number of servings of fruit and of vegetables purchased per week. Results. Households assigned to the intervention purchased an average of 8 (95% confidence interval [CI] = 1.5, 16.9) more servings of vegetables and 2.5 (95% CI = 0.3, 9.5) more servings of fruit per week than did control households. In longitudinal price-adjusted analyses, when the incentive was reduced and then discontinued, the amounts purchased were similar to baseline. Conclusions. Investigation of the financial costs and potential benefits of incentive programs to supermarkets, government agencies, and other stakeholders is needed to identify sustainable interventions. PMID:24625144

  9. Estimation of Correlation Functions by the Random Decrement Technique

    DEFF Research Database (Denmark)

    Brincker, Rune; Krenk, Steen; Jensen, Jakob Laigaard

    responses simulated by two SDOF ARMA models loaded by the same bandlimited white noise. The speed and the accuracy of the RDD technique is compared to the Fast Fourier Transform (FFT) technique. The RDD technique does not involve multiplications, but only additions. Therefore, the technique is very fast......The Random Decrement (RDD) Technique is a versatile technique for characterization of random signals in the time domain. In this paper a short review of the theoretical basis is given, and the technique is illustrated by estimating auto-correlation functions and cross-correlation functions on modal...

  10. Estimation of Correlation Functions by the Random Decrement Technique

    DEFF Research Database (Denmark)

    Brincker, Rune; Krenk, Steen; Jensen, Jacob Laigaard

    1991-01-01

    responses simulated by two SDOF ARMA models loaded by the same band-limited white noise. The speed and the accuracy of the RDD technique is compared to the Fast Fourier Transform (FFT) technique. The RDD technique does not involve multiplications, but only additions. Therefore, the technique is very fast......The Random Decrement (RDD) Technique is a versatile technique for characterization of random signals in the time domain. In this paper a short review of the theoretical basis is given, and the technique is illustrated by estimating auto-correlation functions and cross-correlation functions on modal...

  11. Estimation of Correlation Functions by the Random Decrement Technique

    DEFF Research Database (Denmark)

    Brincker, Rune; Krenk, Steen; Jensen, Jakob Laigaard

    1992-01-01

    responses simulated by two SDOF ARMA models loaded by the same bandlimited white noise. The speed and the accuracy of the RDD technique is compared to the Fast Fourier Transform (FFT) technique. The RDD technique does not involve multiplications, but only additions. Therefore, the technique is very fast......The Random Decrement (RDD) Technique is a versatile technique for characterization of random signals in the time domain. In this paper a short review of the theoretical basis is given, and the technique is illustrated by estimating auto-correlation functions and cross-correlation functions on modal...

  12. The Economic and Social Effects of Reward Based Crowdfunded Technology Projects on the Metropolitan New York Community

    OpenAIRE

    Arboleda, Edwin

    2016-01-01

    Does reward based crowdfunding provide benefits to the local communities where the crowdfunding projects are based from? Drawing from qualitative Data from 14 interviews with successfully funded Kickstarter projects as well as secondary sources, this research looked to quantify the socioeconomic benefits from local based crowdfunding projects. Financial, social, networking and volunteering Data was collected as part of the interviews that were conducted via telephone, email or video confere...

  13. Resistance to extinction, generalization decrement, and conditioned reinforcement.

    Science.gov (United States)

    Dulaney, Alana E; Bell, Matthew C

    2008-06-01

    This study investigated generalization decrement during an extinction resistance-to-change test for pigeon key pecking using a two-component multiple schedule with equal variable-interval 3-min schedules and different reinforcer amounts (one component presented 2-s access to reinforcement and the other 8s). After establishing baseline responding, subjects were assigned to one of the two extinction conditions: hopper stimuli (hopper and hopper light were activated but no food was available) or Control (inactive hopper and hopper light). Responding in the 8-s component was more resistant to extinction than responding in the 2-s component, the hopper stimuli group was more resistant to extinction compared to the Control group, and an interaction between amount of reinforcement, extinction condition, and session block was present. This finding supports generalization decrement as a factor that influences resistance to extinction. Hopper-time data (the amount of time subjects spent with their heads in the hopper) were compared to resistance-to-change data in an investigation of the role of conditioned reinforcement on resistance to change.

  14. A modified random decrement technique for modal identification from nonstationary ambient response data only

    International Nuclear Information System (INIS)

    Lin, Chang Sheng; Chiang, Dar Yun

    2012-01-01

    Modal identification is considered from response data of structural system under nonstationary ambient vibration. In a previous paper, we showed that by assuming the ambient excitation to be nonstationary white noise in the form of a product model, the nonstationary response signals can be converted into free-vibration data via the correlation technique. In the present paper, if the ambient excitation can be modeled as a nonstationary white noise in the form of a product model, then the nonstationary cross random decrement signatures of structural response evaluated at any fixed time instant are shown theoretically to be proportional to the nonstationary cross-correlation functions. The practical problem of insufficient data samples available for evaluating nonstationary random decrement signatures can be approximately resolved by first extracting the amplitude-modulating function from the response and then transforming the nonstationary responses into stationary ones. Modal-parameter identification can then be performed using the Ibrahim time-domain technique, which is effective at identifying closely spaced modes. The theory proposed can be further extended by using the filtering concept to cover the case of nonstationary color excitations. Numerical simulations confirm the validity of the proposed method for identification of modal parameters from nonstationary ambient response data

  15. A computer program for multiple decrement life table analyses.

    Science.gov (United States)

    Poole, W K; Cooley, P C

    1977-06-01

    Life table analysis has traditionally been the tool of choice in analyzing distribution of "survival" times when a parametric form for the survival curve could not be reasonably assumed. Chiang, in two papers [1,2] formalized the theory of life table analyses in a Markov chain framework and derived maximum likelihood estimates of the relevant parameters for the analyses. He also discussed how the techniques could be generalized to consider competing risks and follow-up studies. Although various computer programs exist for doing different types of life table analysis [3] to date, there has not been a generally available, well documented computer program to carry out multiple decrement analyses, either by Chiang's or any other method. This paper describes such a program developed by Research Triangle Institute. A user's manual is available at printing costs which supplements the contents of this paper with a discussion of the formula used in the program listing.

  16. Programmed gradient descent biosorption of strontium ions by Saccaromyces cerevisiae and ashing analysis: A decrement solution for nuclide and heavy metal disposal

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Mingxue [Life Science and Engineering College, Southwest University of Science and Technology, Mianyang, 621010 (China); Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education of China, Mianyang, 621010 (China); Dong, Faqin, E-mail: fqdong@swust.edu.cn [Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education of China, Mianyang, 621010 (China); Zhang, Wei [Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education of China, Mianyang, 621010 (China); Nie, Xiaoqin [Fundamental Science on Nuclear Wastes and Environmental Safety Laboratory, Mianyang, 621010 (China); Sun, Shiyong [Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education of China, Mianyang, 621010 (China); Wei, Hongfu; Luo, Lang; Xiang, Sha; Zhang, Gege [Life Science and Engineering College, Southwest University of Science and Technology, Mianyang, 621010 (China)

    2016-08-15

    Highlights: • A programmed gradient descent biosorption process was designed. • The adsorption and bioaccumulation quantity of strontium ions by yeast cell were measured. • The decrement of biosorbents after biosorption by ashing was analyzed. • A technological flow process of decrement solution for waste disposal was proposed. - Abstract: One of the waste disposal principles is decrement. The programmed gradient descent biosorption of strontium ions by Saccaromyces cerevisiae regarding bioremoval and ashing process for decrement were studied in present research. The results indicated that S. cerevisiae cells showed valid biosorption for strontium ions with greater than 90% bioremoval efficiency for high concentration strontium ions under batch culture conditions. The S. cerevisiae cells bioaccumulated approximately 10% of strontium ions in the cytoplasm besides adsorbing 90% strontium ions on cell wall. The programmed gradient descent biosorption presented good performance with a nearly 100% bioremoval ratio for low concentration strontium ions after 3 cycles. The ashing process resulted in a huge volume and weight reduction ratio as well as enrichment for strontium in the ash. XRD results showed that SrSO{sub 4} existed in ash. Simulated experiments proved that sulfate could adjust the precipitation of strontium ions. Finally, we proposed a technological flow process that combined the programmed gradient descent biosorption and ashing, which could yield great decrement and allow the supernatant to meet discharge standard. This technological flow process may be beneficial for nuclides and heavy metal disposal treatment in many fields.

  17. Carotid flow pulsatility is higher in women with greater decrement in gait speed during multi-tasking.

    Science.gov (United States)

    Gonzales, Joaquin U; James, C Roger; Yang, Hyung Suk; Jensen, Daniel; Atkins, Lee; Al-Khalil, Kareem; O'Boyle, Michael

    2017-05-01

    Central arterial hemodynamics is associated with cognitive impairment. Reductions in gait speed during walking while performing concurrent tasks known as dual-tasking (DT) or multi-tasking (MT) is thought to reflect the cognitive cost that exceeds neural capacity to share resources. We hypothesized that central vascular function would associate with decrements in gait speed during DT or MT. Gait speed was measured using a motion capture system in 56 women (30-80y) without mild-cognitive impairment. Dual-tasking was considered walking at a fast-pace while balancing a tray. Multi-tasking was the DT condition plus subtracting by serial 7's. Applanation tonometry was used for measurement of aortic stiffness and central pulse pressure. Doppler-ultrasound was used to measure blood flow velocity and β-stiffness index in the common carotid artery. The percent change in gait speed was larger for MT than DT (14.1±11.2 vs. 8.7±9.6%, p decrement (third tertile) as compared to women with less decrement (first tertile) in gait speed during MT after adjusting for age, gait speed, and task error. Carotid pulse pressure and β-stiffness did not contribute to these tertile differences. Elevated carotid flow pulsatility and resistance are characteristics found in healthy women that show lower cognitive capacity to walk and perform multiple concurrent tasks. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Progressive decrement PWM algorithm for minimum mean square error inverter output voltage

    International Nuclear Information System (INIS)

    Ghaeb, J.A.; Smadi, M.A.; Ababneh, M.

    2011-01-01

    Highlights: → The main contribution of this work is to provide a better performance for the power inverter operation. → The proposed technique splits the determined original pulse-width of an inverter operation in to many pulses. → The new approach extends the central pulse and shrinks the exterior pulses. → This is leading to an inverter output cycle close to the sinusoidal form of fewer harmonics. - Abstract: The paper proposes two modulation techniques for the power inverter. These new techniques are named progressive decrement PWM algorithm (PDPA) and progressive increment PWM algorithm (PIPA). Both techniques take the determined original pulse-width of an inverter operation and split it to many pulses. In the PDPA technique, the largest width is given to the middle pulse and the width of the boundary pulses is reduced progressively starting from the first boundary-pulse toward the last boundary-pulse. In the PIPA technique, there is a gradual increment instead of decrement. The two techniques have been proved that it can maintain the original pulse-width of the inverter operation. The new approach PDPA extends the central pulse and shrinks the exterior pulses, leading to an inverter output cycle close to the sinusoidal form of fewer harmonic contents. Simulation results are performed to evaluate the performances of the proposed techniques: PDPA and PIPA and to compare them with the well known methods. The main contribution of the proposed PDPA technique is that it provides a better performance for the most harmonic orders compared to the well established sinusoidal PWM technique.

  19. Models of brachial to finger pulse wave distortion and pressure decrement

    NARCIS (Netherlands)

    Gizdulich, P.; Prentza, A.; Wesseling, K.H.

    1997-01-01

    Objective: To model the pulse wave distortion and pressure decrement occurring between brachial and finger arteries. Distortion reversion and decrement correction were also our aims. Methods: Brachial artery pressure was recorded intra-arterially and finger pressure was recorded non-invasively by

  20. Digital-to-analog device for continuous detection of neutron damping decrement in logging

    International Nuclear Information System (INIS)

    Sokolov, Yu.I.; Zinchenko, A.I.; Rudenko, Eh.L.

    1976-01-01

    Algorithms are analyzed for a continuous detection of the damping decrement (DD) of the thermal neutron density in time, characterizing absorptive and diffusion properties of a bed; an an automated measuring device has been developed. The design of a digital calculator involving reguired mathematical and logical operations in the DD measurement by the specified algorithms necessitated the use of a system of elements with a diode-transistor RC logic. Following laboratory tests the mock-up of the calculator was subjected to borehole tests as part of the pulsed neutron logging apparatus of the IGN-4 type. A continuous detection of the DD reciprocal with a parallel recording of the differential and integral curves of pulsed neutron-neutron logging has been performed. The borehole tests revealed the efficiency of the new device and the possibility of its use together with the apparatus of the IGN-4 type

  1. Early decrements in bone density after completion of neoadjuvant chemotherapy in pediatric bone sarcoma patients

    Directory of Open Access Journals (Sweden)

    Hardes Jendrik

    2010-12-01

    Full Text Available Abstract Background Bone mineral density (BMD accrual during childhood and adolescence is important for attaining peak bone mass. BMD decrements have been reported in survivors of childhood bone sarcomas. However, little is known about the onset and development of bone loss during cancer treatment. The objective of this cross-sectional study was to evaluate BMD in newly diagnosed Ewing's and osteosarcoma patients by means of dual-energy x-ray absorptiometry (DXA after completion of neoadjuvant chemotherapy. Methods DXA measurements of the lumbar spine (L2-4, both femora and calcanei were performed perioperatively in 46 children and adolescents (mean age: 14.3 years, range: 8.6-21.5 years. Mean Z-scores, areal BMD (g/cm2, calculated volumetric BMD (g/cm3 and bone mineral content (BMC, g were determined. Results Lumbar spine mean Z-score was -0.14 (95% CI: -0.46 to 0.18, areal BMD was 1.016 g/cm2 (95% CI: 0.950 to 1.082 and volumetric BMD was 0.330 g/cm3 (95% CI: 0.314 to 0.347 which is comparable to healthy peers. For patients with a lower extremity tumor (n = 36, the difference between the affected and non-affected femoral neck was 12.1% (95% CI: -16.3 to -7.9 in areal BMD. The reduction of BMD was more pronounced in the calcaneus with a difference between the affected and contralateral side of 21.7% (95% CI: -29.3 to -14.0 for areal BMD. Furthermore, significant correlations for femoral and calcaneal DXA measurements were found with Spearman-rho coefficients ranging from ρ = 0.55 to ρ = 0.80. Conclusions The tumor disease located in the lower extremity in combination with offloading recommendations induced diminished BMD values, indicating local osteopenia conditions. However, the results revealed no significant decrements of lumbar spine BMD in pediatric sarcoma patients after completion of neoadjuvant chemotherapy. Nevertheless, it has to be taken into account that bone tumor patients may experience BMD decrements or secondary osteoporosis

  2. Relating lab to life: Decrements in attention over time predict math productivity among children with ADHD.

    Science.gov (United States)

    Fosco, Whitney D; Hawk, Larry W

    2017-02-01

    A child's ability to sustain attention over time (AOT) is critical in attention-deficit/hyperactivity disorder (ADHD), yet no prior work has examined the extent to which a child's decrement in AOT on laboratory tasks relates to clinically-relevant behavior. The goal of this study is to provide initial evidence for the criterion validity of laboratory assessments of AOT. A total of 20 children with ADHD (7-12 years of age) who were enrolled in a summer treatment program completed two lab attention tasks (a continuous performance task and a self-paced choice discrimination task) and math seatwork. Analyses focused on relations between attention task parameters and math productivity. Individual differences in overall attention (OA) measures (averaged across time) accounted for 23% of the variance in math productivity, supporting the criterion validity of lab measures of attention. The criterion validity was enhanced by consideration of changes in AOT. Performance on all laboratory attention measures deteriorated as time-on-task increased, and individual differences in the decrement in AOT accounted for 40% of the variance in math productivity. The only variable to uniquely predict math productivity was from the self-paced choice discrimination task. This study suggests that attention tasks in the lab do predict a clinically-relevant target behavior in children with ADHD, supporting their use as a means to study attention processes in a controlled environment. Furthermore, this prediction is improved when attention is examined as a function of time-on-task and when the attentional demands are consistent between lab and life contexts.

  3. Incentivizing healthy eating in children: An investigation of the "ripple" and "temporal" effects of a reward-based intervention.

    Science.gov (United States)

    Toossi, Saied

    2017-10-01

    Although previous studies have established the effectiveness of using small reward-based incentives in inducing the choice and consumption of healthier foods among children, little is known about their impact outside of experimental settings or their effectiveness over time when administered daily. This paper presents the results of a field experiment conducted to provide insight on these matters. The study employs a removed treatment within-subject design and was conducted at a summer program catering to low-income children between the ages of 5 and 12. The month long experiment-wherein participants were offered a small prize for choosing a fruit cup for dessert after lunch in lieu of cookies-involved 23 children between the ages of 5 and 8. Corroborating existing studies, the introduction of small reward-based incentives in this context was found to induce large increases in the number of children choosing the healthy dessert options after lunch, but disaggregating the results by week and day suggests that their impact diminished over time. Attempts to ascertain their effect outside of experimental settings did not indicate that the introduction of rewards had any adverse effects, but also did not provide definitive conclusions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. A tribute to Charlie Chaplin: Induced positive affect improves reward-based decision-learning in Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    K. Richard eRidderinkhof

    2012-06-01

    Full Text Available Reward-based decision-learning refers to the process of learning to select those actions that lead to rewards while avoiding actions that lead to punishments. This process, known to rely on dopaminergic activity in striatal brain regions, is compromised in Parkinson’s disease (PD. We hypothesized that such decision-learning deficits are alleviated by induced positive affect, which is thought to incur transient boosts in midbrain and striatal dopaminergic activity. Computational measures of probabilistic reward-based decision-learning were determined for 51 patients diagnosed with PD. Previous work has shown these measures to rely on the nucleus caudatus (outcome evaluation during the early phases of learning and the putamen (reward prediction during later phases of learning. We observed that induced positive affect facilitated learning, through its effects on reward prediction rather than outcome evaluation. Viewing a few minutes of comedy clips served to remedy dopamine-related problems in putamen-based frontostriatal circuitry and, consequently, in learning to predict which actions will yield reward.

  5. Noise masking of S-cone increments and decrements.

    Science.gov (United States)

    Wang, Quanhong; Richters, David P; Eskew, Rhea T

    2014-11-12

    S-cone increment and decrement detection thresholds were measured in the presence of bipolar, dynamic noise masks. Noise chromaticities were the L-, M-, and S-cone directions, as well as L-M, L+M, and achromatic (L+M+S) directions. Noise contrast power was varied to measure threshold Energy versus Noise (EvN) functions. S+ and S- thresholds were similarly, and weakly, raised by achromatic noise. However, S+ thresholds were much more elevated by S, L+M, L-M, L- and M-cone noises than were S- thresholds, even though the noises consisted of two symmetric chromatic polarities of equal contrast power. A linear cone combination model accounts for the overall pattern of masking of a single test polarity well. L and M cones have opposite signs in their effects upon raising S+ and S- thresholds. The results strongly indicate that the psychophysical mechanisms responsible for S+ and S- detection, presumably based on S-ON and S-OFF pathways, are distinct, unipolar mechanisms, and that they have different spatiotemporal sampling characteristics, or contrast gains, or both. © 2014 ARVO.

  6. Use of EEG workload indices for diagnostic monitoring of vigilance decrement.

    Science.gov (United States)

    Kamzanova, Altyngul T; Kustubayeva, Almira M; Matthews, Gerald

    2014-09-01

    A study was run to test which of five electroencephalographic (EEG) indices was most diagnostic of loss of vigilance at two levels of workload. EEG indices of alertness include conventional spectral power measures as well as indices combining measures from multiple frequency bands, such as the Task Load Index (TLI) and the Engagement Index (El). However, it is unclear which indices are optimal for early detection of loss of vigilance. Ninety-two participants were assigned to one of two experimental conditions, cued (lower workload) and uncued (higher workload), and then performed a 40-min visual vigilance task. Performance on this task is believed to be limited by attentional resource availability. EEG was recorded continuously. Performance, subjective state, and workload were also assessed. The task showed a vigilance decrement in performance; cuing improved performance and reduced subjective workload. Lower-frequency alpha (8 to 10.9 Hz) and TLI were most sensitive to the task parameters. The magnitude of temporal change was larger for lower-frequency alpha. Surprisingly, higher TLI was associated with superior performance. Frontal theta and El were influenced by task workload only in the final period of work. Correlational data also suggested that the indices are distinct from one another. Lower-frequency alpha appears to be the optimal index for monitoring vigilance on the task used here, but further work is needed to test how diagnosticity of EEG indices varies with task demands. Lower-frequency alpha may be used to diagnose loss of operator alertness on tasks requiring vigilance.

  7. Towards a cognitive robotics methodology for reward-based decision-making: dynamical systems modelling of the Iowa Gambling Task

    Science.gov (United States)

    Lowe, Robert; Ziemke, Tom

    2010-09-01

    The somatic marker hypothesis (SMH) posits that the role of emotions and mental states in decision-making manifests through bodily responses to stimuli of import to the organism's welfare. The Iowa Gambling Task (IGT), proposed by Bechara and Damasio in the mid-1990s, has provided the major source of empirical validation to the role of somatic markers in the service of flexible and cost-effective decision-making in humans. In recent years the IGT has been the subject of much criticism concerning: (1) whether measures of somatic markers reveal that they are important for decision-making as opposed to behaviour preparation; (2) the underlying neural substrate posited as critical to decision-making of the type relevant to the task; and (3) aspects of the methodological approach used, particularly on the canonical version of the task. In this paper, a cognitive robotics methodology is proposed to explore a dynamical systems approach as it applies to the neural computation of reward-based learning and issues concerning embodiment. This approach is particularly relevant in light of a strongly emerging alternative hypothesis to the SMH, the reversal learning hypothesis, which links, behaviourally and neurocomputationally, a number of more or less complex reward-based decision-making tasks, including the 'A-not-B' task - already subject to dynamical systems investigations with a focus on neural activation dynamics. It is also suggested that the cognitive robotics methodology may be used to extend systematically the IGT benchmark to more naturalised, but nevertheless controlled, settings that might better explore the extent to which the SMH, and somatic states per se, impact on complex decision-making.

  8. Reassessment of the relationship between M-protein decrement and survival in multiple myeloma.

    OpenAIRE

    Palmer, M.; Belch, A.; Hanson, J.; Brox, L.

    1989-01-01

    The relationship between percentage M-protein decrement and survival is assessed in 134 multiple myeloma patients. The correlation did not achieve statistical significance (P = 0.069). Multivariate analysis using the Cox proportional hazards model, including a number of previously recognised prognostic factors, showed only percentage M-protein decrement, creatinine and haemoglobin to be significantly correlated with survival. However, the R'-statistic for each of these variables was low, indi...

  9. Reward-based learning under hardware constraints - Using a RISC processor embedded in a neuromorphic substrate

    Directory of Open Access Journals (Sweden)

    Simon eFriedmann

    2013-09-01

    Full Text Available In this study, we propose and analyze in simulations a new, highly flexible method of imple-menting synaptic plasticity in a wafer-scale, accelerated neuromorphic hardware system. Thestudy focuses on globally modulated STDP, as a special use-case of this method. Flexibility isachieved by embedding a general-purpose processor dedicated to plasticity into the wafer. Toevaluate the suitability of the proposed system, we use a reward modulated STDP rule in a spiketrain learning task. A single layer of neurons is trained to fire at specific points in time withonly the reward as feedback. This model is simulated to measure its performance, i.e. the in-crease in received reward after learning. Using this performance as baseline, we then simulatethe model with various constraints imposed by the proposed implementation and compare theperformance. The simulated constraints include discretized synaptic weights, a restricted inter-face between analog synapses and embedded processor, and mismatch of analog circuits. Wefind that probabilistic updates can increase the performance of low-resolution weights, a simpleinterface between analog synapses and processor is sufficient for learning, and performance isinsensitive to mismatch. Further, we consider communication latency between wafer and theconventional control computer system that is simulating the environment. This latency increasesthe delay, with which the reward is sent to the embedded processor. Because of the time continu-ous operation of the analog synapses, delay can cause a deviation of the updates as compared tothe not delayed situation. We find that for highly accelerated systems latency has to be kept to aminimum. This study demonstrates the suitability of the proposed implementation to emulatethe selected reward modulated STDP learning rule. It is therefore an ideal candidate for imple-mentation in an upgraded version of the wafer-scale system developed within the BrainScaleSproject.

  10. Generalization decrement and not overshadowing by associative competition among pairs of landmarks in a navigation task.

    Science.gov (United States)

    Chamizo, Victoria D; Rodríguez, Clara A; Espinet, Alfredo; Mackintosh, N J

    2012-07-01

    When they are trained in a Morris water maze to find a hidden platform, whose location is defined by a number of equally spaced visual landmarks round the circumference of the pool, rats are equally able to find the platform when tested with any two of the landmarks (Prados, & Trobalon, 1998; Rodrigo, Chamizo, McLaren, & Mackintosh, 1997). This suggests that none of the landmarks was completely overshadowed by any of the others. In Experiment 1 one pair of groups was trained with four equally salient visual landmarks spaced at equal intervals around the edge of the pool, while a second pair was trained with two landmarks only, either relatively close to or far from the hidden platform. After extensive training, both male and female rats showed a reciprocal overshadowing effect: on a test with two landmarks only (either close to or far from the platform), rats trained with four landmarks spent less time in the platform quadrant than those trained with only two. Experiment 2 showed that animals trained with two landmarks and then tested with four also performed worse on test than those trained and tested with two landmarks only. This suggests that generalization decrement, rather than associative competition, provides a sufficient explanation for the overshadowing observed in Experiment 1. Experiment 3 provided a within-experiment replication of the results of Experiments 1 and 2. Finally, Experiment 4 showed that rats trained with a configuration of two landmarks learn their identity.

  11. Effects of a peer modelling and rewards-based intervention to increase fruit and vegetable consumption in children.

    Science.gov (United States)

    Lowe, C F; Horne, P J; Tapper, K; Bowdery, M; Egerton, C

    2004-03-01

    To measure children's consumption of, and liking for, fruit and vegetables and how these are altered by a peer modelling and rewards-based intervention. In this initial evaluation of the programme, children's consumption of fruit and vegetables were compared within and across baseline and intervention phases. Three primary schools in England and Wales. In total, 402 children, aged from 4 to 11 y. Over 16 days, children watched six video adventures featuring heroic peers (the Food Dudes) who enjoy eating fruit and vegetables, and received small rewards for eating these foods themselves. Fruit and vegetable consumption was measured (i) in school at lunchtime and snacktime using a five-point observation scale, with inter-rated reliability and weighed validation tests; and (ii) at home using parental recall. A questionnaire measured children's liking for fruit and vegetables before and after the intervention. Consumption during the intervention was significantly higher than during baseline at lunchtime and at snacktime (PASDA, Co-operative Group, Safeway, Sainsbury, Somerfield, Tesco and Birds Eye Wall's.

  12. Reassessment of the relationship between M-protein decrement and survival in multiple myeloma.

    Science.gov (United States)

    Palmer, M.; Belch, A.; Hanson, J.; Brox, L.

    1989-01-01

    The relationship between percentage M-protein decrement and survival is assessed in 134 multiple myeloma patients. The correlation did not achieve statistical significance (P = 0.069). Multivariate analysis using the Cox proportional hazards model, including a number of previously recognised prognostic factors, showed only percentage M-protein decrement, creatinine and haemoglobin to be significantly correlated with survival. However, the R'-statistic for each of these variables was low, indicating that their prognostic power is weak. We conclude that neither the percentage M-protein decrement nor the response derived from it can be used as an accurate means of assessing the efficacy of treatment in myeloma. Mature survival data alone should be used for this purpose. PMID:2757916

  13. Reassessment of the relationship between M-protein decrement and survival in multiple myeloma.

    Science.gov (United States)

    Palmer, M; Belch, A; Hanson, J; Brox, L

    1989-01-01

    The relationship between percentage M-protein decrement and survival is assessed in 134 multiple myeloma patients. The correlation did not achieve statistical significance (P = 0.069). Multivariate analysis using the Cox proportional hazards model, including a number of previously recognised prognostic factors, showed only percentage M-protein decrement, creatinine and haemoglobin to be significantly correlated with survival. However, the R'-statistic for each of these variables was low, indicating that their prognostic power is weak. We conclude that neither the percentage M-protein decrement nor the response derived from it can be used as an accurate means of assessing the efficacy of treatment in myeloma. Mature survival data alone should be used for this purpose.

  14. Influence of dynamic dislocation drag on amplitude dependences of damping decrement and modulus defect in lead

    International Nuclear Information System (INIS)

    Soifer, Y.M.; Golosovskii, M.A.; Kobelev, N.P.

    1981-01-01

    A study was made of the amplitude dependences of the damping decrement and the modulus defect in lead at low temperatures at frequencies of 100 kHz and 5 MHz. It was shown that in pure lead at high frequencies a change in the amplitude dependences of the damping decrement and the modulus defect under the superconducting transition is due mainly to the change in the losses caused by the dynamic drag of dislocations whereas in measurements at low frequencies the influence of the superconducting transition is due to the change in the conditions of dislocation unpinning from point defects. The influence of the dynamic dislocation drag on the amplitude dependences of the damping decrement and the modulus defect is calculated and a method is presented for experimental estimation of the contribution of dynamic effects to the amplitude-dependent internal friction

  15. Multiple variables explain the variability in the decrement in VO2max during acute hypobaric hypoxia.

    Science.gov (United States)

    Robergs, R A; Quintana, R; Parker, D L; Frankel, C C

    1998-06-01

    We used multiple regression analyses to determine the relationships between the decrement in sea level (SL, 760 Torr) VO2max during hypobaric hypoxia (HH) and variables that could alter or be related to the decrement in VO2max. HH conditions consisted of 682 Torr, 632 Torr, and 566 Torr, and the measured independent variables were SL-VO2max, SL lactate threshold (SL-LT), the change in hemoglobin saturation at VO2max between 760 and 566 Torr (delta SaO2max), lean body mass (LBM), and gender. Male (N = 14) and female (N = 14) subjects of varied fitness, training status, and residential altitude (1,640-2,460 m) completed cycle ergometry tests of VO2max at each HH condition under randomized and single-blinded conditions. VO2max decreased significantly from 760 Torr after 682 Torr (approximately 915 m) (3.5 +/- 0.9 to 3.4 +/- 0.8 L.min-1, P = 0.0003). Across all HH conditions, the slope of the relative decrement in VO2max (%VO2max) during HH was -9.2%/100 mm Hg (-8.1%/1000 m) with an initial decrease from 100% estimated to occur below 705 Torr (610 m). Step-wise multiple regression revealed that SL-VO2max, SL-LT, delta SaO2max, LBM, and gender each significantly combined to account for 89.03% of the variance in the decrement in VO2max (760-566 Torr) (P decrement in VO2max during HH. The unique variance explanation afforded by SL-LT, LBM, and gender suggests that issues pertaining to oxygen diffusion within skeletal muscle may add to the explanation of between subjects variability in the decrement in VO2max during HH.

  16. Neuromodulatory Adaptive Combination of Correlation-based Learning in Cerebellum and Reward-based Learning in Basal Ganglia for Goal-directed Behavior Control

    DEFF Research Database (Denmark)

    Dasgupta, Sakyasingha; Wörgötter, Florentin; Manoonpong, Poramate

    2014-01-01

    Goal-directed decision making in biological systems is broadly based on associations between conditional and unconditional stimuli. This can be further classified as classical conditioning (correlation-based learning) and operant conditioning (reward-based learning). A number of computational...... and experimental studies have well established the role of the basal ganglia in reward-based learning, where as the cerebellum plays an important role in developing specific conditioned responses. Although viewed as distinct learning systems, recent animal experiments point toward their complementary role...... in behavioral learning, and also show the existence of substantial two-way communication between these two brain structures. Based on this notion of co-operative learning, in this paper we hypothesize that the basal ganglia and cerebellar learning systems work in parallel and interact with each other. We...

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

    Directory of Open Access Journals (Sweden)

    Micheline eMaire

    2014-03-01

    Full Text Available 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 behavioural vulnerability.

  18. Improvement of Frequency Domain Output Only Modal Identification from the Application of the Random Decrement Technique

    DEFF Research Database (Denmark)

    Rodrigues, J.; Brincker, Rune; Andersen, P.

    2004-01-01

    This paper explores the idea of estimating the spectral densities as the Fourier transform of the random decrement functions for the application of frequency domain output-only modal identification methods. The gains in relation to the usual procedure of computing the spectral densities directly...

  19. Calculation of the mean scattering angle, the logarithmic decrement and its mean square

    International Nuclear Information System (INIS)

    Bersillon, O.; Caput, B.

    1984-06-01

    The calculation of the mean scattering angle, the logarithmic decrement and its mean square, starting from the Legendre polynomial expansion coefficients of the relevant elastic scattering angular distribution, is numerically studied with different methods, one of which is proposed for the usual determination of these quantities which are present in the evaluated data files ENDF [fr

  20. On the search for an appropriate metric for reaction time to suprathreshold increments and decrements.

    Science.gov (United States)

    Vassilev, Angel; Murzac, Adrian; Zlatkova, Margarita B; Anderson, Roger S

    2009-03-01

    Weber contrast, DeltaL/L, is a widely used contrast metric for aperiodic stimuli. Zele, Cao & Pokorny [Zele, A. J., Cao, D., & Pokorny, J. (2007). Threshold units: A correct metric for reaction time? Vision Research, 47, 608-611] found that neither Weber contrast nor its transform to detection-threshold units equates human reaction times in response to luminance increments and decrements under selective rod stimulation. Here we show that their rod reaction times are equated when plotted against the spatial luminance ratio between the stimulus and its background (L(max)/L(min), the larger and smaller of background and stimulus luminances). Similarly, reaction times to parafoveal S-cone selective increments and decrements from our previous studies [Murzac, A. (2004). A comparative study of the temporal characteristics of processing of S-cone incremental and decremental signals. PhD thesis, New Bulgarian University, Sofia, Murzac, A., & Vassilev, A. (2004). Reaction time to S-cone increments and decrements. In: 7th European conference on visual perception, Budapest, August 22-26. Perception, 33, 180 (Abstract).], are better described by the spatial luminance ratio than by Weber contrast. We assume that the type of stimulus detection by temporal (successive) luminance discrimination, by spatial (simultaneous) luminance discrimination or by both [Sperling, G., & Sondhi, M. M. (1968). Model for visual luminance discrimination and flicker detection. Journal of the Optical Society of America, 58, 1133-1145.] determines the appropriateness of one or other contrast metric for reaction time.

  1. Models of brachial to finger pulse wave distortion and pressure decrement.

    Science.gov (United States)

    Gizdulich, P; Prentza, A; Wesseling, K H

    1997-03-01

    To model the pulse wave distortion and pressure decrement occurring between brachial and finger arteries. Distortion reversion and decrement correction were also our aims. Brachial artery pressure was recorded intra-arterially and finger pressure was recorded non-invasively by the Finapres technique in 53 adult human subjects. Mean pressure was subtracted from each pressure waveform and Fourier analysis applied to the pulsations. A distortion model was estimated for each subject and averaged over the group. The average inverse model was applied to the full finger pressure waveform. The pressure decrement was modelled by multiple regression on finger systolic and diastolic levels. Waveform distortion could be described by a general, frequency dependent model having a resonance at 7.3 Hz. The general inverse model has an anti-resonance at this frequency. It converts finger to brachial pulsations thereby reducing average waveform distortion from 9.7 (s.d. 3.2) mmHg per sample for the finger pulse to 3.7 (1.7) mmHg for the converted pulse. Systolic and diastolic level differences between finger and brachial arterial pressures changed from -4 (15) and -8 (11) to +8 (14) and +8 (12) mmHg, respectively, after inverse modelling, with pulse pressures correct on average. The pressure decrement model reduced both the mean and the standard deviation of systolic and diastolic level differences to 0 (13) and 0 (8) mmHg. Diastolic differences were thus reduced most. Brachial to finger pulse wave distortion due to wave reflection in arteries is almost identical in all subjects and can be modelled by a single resonance. The pressure decrement due to flow in arteries is greatest for high pulse pressures superimposed on low means.

  2. Critical Assessment Of The Issues In The Application Of Hilbert Transform To Compute The Logarithmic Decrement

    Directory of Open Access Journals (Sweden)

    Majewski M.

    2015-06-01

    Full Text Available The parametric OMI (Optimization in Multiple Intervals, the Yoshida-Magalas (YM and a novel Hilbert-twin (H-twin methods are advocated for computing the logarithmic decrement in the field of internal friction and mechanical spectroscopy of solids. It is shown that dispersion in experimental points results mainly from the selection of the computing methods, the number of oscillations, and noise. It is demonstrated that conventional Hilbert transform method suffers from high dispersion in internal friction values. It is unequivocally demonstrated that the Hilbert-twin method, which yields a ‘true envelope’ for exponentially damped harmonic oscillations is superior to conventional Hilbert transform method. The ‘true envelope’ of free decaying strain signals calculated from the Hilbert-twin method yields excellent estimation of the logarithmic decrement in metals, alloys, and solids.

  3. The multiple decrement life table: a unifying framework for cause-of-death analysis in ecology.

    Science.gov (United States)

    Carey, James R

    1989-01-01

    The multiple decrement life table is used widely in the human actuarial literature and provides statistical expressions for mortality in three different forms: i) the life table from all causes-of-death combined; ii) the life table disaggregated into selected cause-of-death categories; and iii) the life table with particular causes and combinations of causes eliminated. The purpose of this paper is to introduce the multiple decrement life table to the ecological literature by applying the methods to published death-by-cause information on Rhagoletis pomonella. Interrelations between the current approach and conventional tools used in basic and applied ecology are discussed including the conventional life table, Key Factor Analysis and Abbott's Correction used in toxicological bioassay.

  4. Critical Assessment Of The Issues In The Application Of Hilbert Transform To Compute The Logarithmic Decrement

    OpenAIRE

    Majewski M.; Magalas L.B.

    2015-01-01

    The parametric OMI (Optimization in Multiple Intervals), the Yoshida-Magalas (YM) and a novel Hilbert-twin (H-twin) methods are advocated for computing the logarithmic decrement in the field of internal friction and mechanical spectroscopy of solids. It is shown that dispersion in experimental points results mainly from the selection of the computing methods, the number of oscillations, and noise. It is demonstrated that conventional Hilbert transform method suffers from high dispersion in in...

  5. Fast concurrent array-based stacks, queues and deques using fetch-and-increment-bounded, fetch-and-decrement-bounded and store-on-twin synchronization primitives

    Science.gov (United States)

    Chen, Dong; Gara, Alana; Heidelberger, Philip; Kumar, Sameer; Ohmacht, Martin; Steinmacher-Burow, Burkhard; Wisniewski, Robert

    2014-09-16

    Implementation primitives for concurrent array-based stacks, queues, double-ended queues (deques) and wrapped deques are provided. In one aspect, each element of the stack, queue, deque or wrapped deque data structure has its own ticket lock, allowing multiple threads to concurrently use multiple elements of the data structure and thus achieving high performance. In another aspect, new synchronization primitives FetchAndIncrementBounded (Counter, Bound) and FetchAndDecrementBounded (Counter, Bound) are implemented. These primitives can be implemented in hardware and thus promise a very fast throughput for queues, stacks and double-ended queues.

  6. Critical Review of Selected Components of RIPD (Radiation-Induced Performance Decrement)

    Science.gov (United States)

    2012-12-01

    The response of the emetic centers elicits the signs and symptoms of UG distress. The levels of A are converted to a measure of severity of emesis ...Mean n Mean n developmen ms as emes cally and ph y need an a emesis bec antifying it i odel f cell loss in rotracted rad he lethal/po n, the prolif...210. Andrews, P.L.R., and Horn C.C., 2006. “Signals for nausea and emesis : Implications for models of upper gastrointestinal diseases,” Auton

  7. Quantifying the determinants of decremental response in critical ventricular tachycardia substrate.

    Science.gov (United States)

    Beheshti, Mohammadali; Nayyar, Sachin; Magtibay, Karl; Massé, Stéphane; Porta-Sanchez, Andreu; Haldar, Shouvik; Bhaskaran, Abhishek; Vigmond, Edward; Nanthakumar, Kumaraswamy

    2018-05-28

    Decremental response evoked with extrastimulation (DEEP) is a useful tool for determining diastolic return path of ventricular tachycardia (VT). Though a targeted VT ablation is feasible with this approach, determinants of DEEP response have not been studied OBJECTIVES: To elucidate the effects of clinically relevant factors, specifically, the proximity of the stimulation site to the arrhythmogenic scar, stimulation wave direction, number of channels open in the scar, size of the scar and number of extra stimuli on decrement and entropy of DEEP potentials. In a 3-dimensional bi-domain simulation of human ventricular tissue (TNNP cell model), an irregular subendocardial myopathic region was generated. An irregular channel of healthy tissue with five potential entry branches was shaped into the myopathic region. A bipolar electrogram was derived from two electrodes positioned in the centre of the myopathic region. Evoked delays between far-field and local Electrogram (EGM) following an extrastimulus (S1-S2, 500-350 ms) were measured as the stimulation site, channel branches, and inexcitable tissue size were altered. Stimulation adjacent to the inexcitable tissue from the side opposite to the point-of-entry produces longest DEEP delay. The DEEP delay shortens when the stimulation point is farther away from the scar, and it decreases maximally when stimulation is done from a site beside a conduction barrier. Entropy increases with S2 when stimulation site is from farther away. An unprotected channel structure with multiple side-branch openings had shorter DEEP delay compared to a protected channel structure with a paucity of additional side-branch openings and a point-of-entry on the side opposite to the pacing source. Addition of a second shorter extrastimulus did not universally lead to higher DEEP delay CONCLUSIONS: Location and direction of the wavefront in relation to scar entry and size of scar determine the degree of evoked response while the number of

  8. Estimation of the Coefficient of Restitution of Rocking Systems by the Random Decrement Technique

    DEFF Research Database (Denmark)

    Brincker, Rune; Demosthenous, Milton; Manos, George C.

    1994-01-01

    The aim of this paper is to investigate the possibility of estimating an average damping parameter for a rocking system due to impact, the so-called coefficient of restitution, from the random response, i.e. when the loads are random and unknown, and the response is measured. The objective...... is to obtain an estimate of the free rocking response from the measured random response using the Random Decrement (RDD) Technique, and then estimate the coefficient of restitution from this free response estimate. In the paper this approach is investigated by simulating the response of a single degree...

  9. The Commonality Between Approaches to Determine Jump Fatigue During Basketball Activity in Junior Players: In-Game Versus Across-Game Decrements.

    Science.gov (United States)

    Scanlan, Aaron T; Fox, Jordan L; Borges, Nattai R; Dalbo, Vincent J

    2017-02-01

    Declines in high-intensity activity during game play (in-game approach) and performance tests measured pre- and postgame (across-game approach) have been used to assess player fatigue in basketball. However, a direct comparison of these approaches is not available. Consequently, this study examined the commonality between in- and across-game jump fatigue during simulated basketball game play. Australian, state-level, junior male basketball players (n = 10; 16.6 ± 1.1 y, 182.4 ± 4.3 cm, 68.3 ± 10.2 kg) completed 4 × 10-min standardized quarters of simulated basketball game play. In-game jump height during game play was measured using video analysis, while across-game jump height was determined pre-, mid-, and postgame play using an in-ground force platform. Jump height was determined using the flight-time method, with jump decrement calculated for each approach across the first half, second half, and entire game. A greater jump decrement was apparent for the in-game approach than for the across-game approach in the first half (37.1% ± 11.6% vs 1.7% ± 6.2%; P = .005; d = 3.81, large), while nonsignificant, large differences were evident between approaches in the second half (d = 1.14) and entire game (d = 1.83). Nonsignificant associations were evident between in-game and across-game jump decrement, with shared variances of 3-26%. Large differences and a low commonality were observed between in- and across-game jump fatigue during basketball game play, suggesting that these approaches measure different constructs. Based on our findings, it is not recommended that basketball coaches use these approaches interchangeably to monitor player fatigue across the season.

  10. Ghrelin signaling in the ventral tegmental area mediates both reward-based feeding and fasting-induced hyperphagia on high-fat diet.

    Science.gov (United States)

    Wei, X J; Sun, B; Chen, K; Lv, B; Luo, X; Yan, J Q

    2015-08-06

    Ghrelin is a potent orexigenic hormone that acts in the central nervous system to stimulate food intake via the growth hormone secretagogue receptor (GHSR) that is abundantly expressed in the ventral tegmental area (VTA). Not only does ghrelin modulate feeding behavior via a homeostatic mechanism, but numerous studies have identified ghrelin as a key regulator of reward-based hedonic feeding behaviors. Nutritional states influence ghrelin and GHSR expression as well as the behavioral sensitivity to reward-inducing stimuli. In the current study, we examined the role of ghrelin at the VTA level in food intake in two different nutritional states, satiety and hunger, by using a restricted feeding model. In this model, rats were conditioned to a daily 3-h (h) feeding session on standard chow for 10days and a high-fat diet (HFD) was supplied either in the third hour after 2h of chow diet intake, or at the beginning of a daily meal on the test day. We found that intra-VTA microinjection of 1, 2, and 4μg of ghrelin, induced a dose-related increase of 1h of reward-based feeding on HFD in sated rats, as well as a 24-h body weight gain. The overconsumption stimulated by ghrelin could be attenuated by 10μg of direct infusion of the ghrelin receptor antagonist D-Lys3-GHRP-6 into the VTA. Moreover, our data showed that the injection of 1, 2, and 4μg of ghrelin in the VTA, enhanced fasting-induced hyperphagia on HFD in a dose-related manner following a 21-h food restriction as well as a 24-h body weight gain. Conversely, hyperphagia on HFD that is potentiated by ghrelin could be blocked by pretreatment with a 10-μg D-Lys3-GHRP-6 intra-VTA microinjection. Collectively, these data demonstrate that ghrelin signaling at the VTA level mediates both reward-based eating and fasting-induced hyperphagia and provides a primary target for the control of the intake of rewarding food. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  11. Planning Decrements in Healthy Aging: Mediation Effects of Fluid Reasoning and Working Memory Capacity.

    Science.gov (United States)

    Köstering, Lena; Leonhart, Rainer; Stahl, Christoph; Weiller, Cornelius; Kaller, Christoph P

    2016-03-01

    Although age-related differences in planning ability are well known, their cognitive foundations remain a matter of contention. To elucidate the specific processes underlying planning decrements in older age, the relative contributions of fluid reasoning, working memory (WM) capacity, and processing speed to accuracy on the Tower of London (TOL) planning task were investigated. Mediation analyses were used to relate overall and search depth-related TOL accuracy from older (N = 106; 60-89 years) and younger adults (N = 69; 18-54 years) to age and measures of fluid reasoning, WM capacity, and speed. For overall planning, fluid abilities mediated the effects of age, WM capacity, and speed in older adults. By contrast, fluid abilities and WM capacity mediated each other in younger adults. For planning accuracy under low demands on the depth of search, WM capacity was specifically important in older age, whereas younger adults recruited both WM capacity and fluid reasoning. Under high search-depth-demands, fluid abilities underlay the cognitive operations critical for resolving move interdependencies in both age groups. Fluid abilities and WM capacity undergo significant changes from younger to older age in their unique contribution to planning, which might represent a mechanism whereby planning decrements in older age are brought about. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. An analysis of decrements in vital capacity as an index of pulmonary oxygen toxicity.

    Science.gov (United States)

    Harabin, A L; Homer, L D; Weathersby, P K; Flynn, E T

    1987-09-01

    Decrements in vital capacity (% delta VC) were proposed by the Pennsylvania group in the early 1970s as an index of O2-induced lung damage. These workers used the combined effects of PO2 and time of exposure to develop recommendations to limit expected % delta VC. Adopting this general approach, we fitted human pulmonary O2 toxicity data to the hyperbolic equation % delta VC = Bs.(PO2 - B1).(time)B3 using a nonlinear least squares analysis. In addition to the data considered in 1970, our analysis included new data available from the literature. The best fit was obtained when 1) an individual slope parameter, Bs, was estimated for each subject instead of an average slope; 2) PO2 asymptote B1 = 0.38 ATA; and 3) exponent B3 = 1.0. Wide individual variation imposed large uncertainty on any % delta VC prediction. A 12-h exposure to a PO2 of 1 ATA would be expected to yield a median VC decrement of 4%. The 80% confidence limits, however, included changes from +1.0 and -12% delta VC. Until an improved index of pulmonary O2 toxicity is developed, a simplified expression % delta VC = -0.011.(PO2 - 0.5).time (PO2 in ATA and time in min) can be used to predict a median response with little loss in predictability. The limitations of changes in VC as an index are discussed.

  13. Neuromodulatory adaptive combination of correlation-based learning in cerebellum and reward-based learning in basal ganglia for goal-directed behavior control.

    Science.gov (United States)

    Dasgupta, Sakyasingha; Wörgötter, Florentin; Manoonpong, Poramate

    2014-01-01

    Goal-directed decision making in biological systems is broadly based on associations between conditional and unconditional stimuli. This can be further classified as classical conditioning (correlation-based learning) and operant conditioning (reward-based learning). A number of computational and experimental studies have well established the role of the basal ganglia in reward-based learning, where as the cerebellum plays an important role in developing specific conditioned responses. Although viewed as distinct learning systems, recent animal experiments point toward their complementary role in behavioral learning, and also show the existence of substantial two-way communication between these two brain structures. Based on this notion of co-operative learning, in this paper we hypothesize that the basal ganglia and cerebellar learning systems work in parallel and interact with each other. We envision that such an interaction is influenced by reward modulated heterosynaptic plasticity (RMHP) rule at the thalamus, guiding the overall goal directed behavior. Using a recurrent neural network actor-critic model of the basal ganglia and a feed-forward correlation-based learning model of the cerebellum, we demonstrate that the RMHP rule can effectively balance the outcomes of the two learning systems. This is tested using simulated environments of increasing complexity with a four-wheeled robot in a foraging task in both static and dynamic configurations. Although modeled with a simplified level of biological abstraction, we clearly demonstrate that such a RMHP induced combinatorial learning mechanism, leads to stabler and faster learning of goal-directed behaviors, in comparison to the individual systems. Thus, in this paper we provide a computational model for adaptive combination of the basal ganglia and cerebellum learning systems by way of neuromodulated plasticity for goal-directed decision making in biological and bio-mimetic organisms.

  14. The Atacama Cosmology Telescope: Detection or Sunyaev-Zel'Dovich Decrement in Groups and Clusters Associated with Luminous Red Galaxies

    Science.gov (United States)

    Hand, Nick; Appel, John William; Battaglia, Nick; Bond, J. Richard; Das, Sudeep; Devlin, Mark J.; Dunkley, Joanna; Dunner, Rolando; Essinger-Hileman, Thomas; Fowler, Joseph W.; hide

    2010-01-01

    We present a detection of the Sunyaev-Zel'dovich (SZ) decrement associated with the Luminous Red Galaxy (LRG) sample of the Sloan Digital Sky Survey. The SZ data come from 148 GHz maps of the equatorial region made by the Atacama Cosmology Telescope (ACT). The LRG sample is divided by luminosity into four bins, and estimates for the central Sunyaev-Zel'dovich temperature decrement are calculated through a stacking process. We detect and account for a bias of the SZ signal due to weak radio sources. We use numerical simulations to relate the observed decrement to Y(sub 200) and clustering properties to relate the galaxy luminosity bins to mass. We also use a relation between BCG luminosity and cluster mass based on stacked gravitational lensing measurements to estimate the characteristic halo masses. The masses are found to be in the range approx.10(exp 13) - 10(exp 14)/h Stellar Mass, a lower range than has been previously probed.

  15. Submitting to defeat: social anxiety, dominance threat, and decrements in testosterone.

    Science.gov (United States)

    Maner, Jon K; Miller, Saul L; Schmidt, Norman B; Eckel, Lisa A

    2008-08-01

    Although theory suggests a link between social anxiety and social dominance, direct empirical evidence for this link is limited. The present experiment tested the hypothesis that socially anxious individuals, particularly men, would respond to a social-dominance threat by exhibiting decrements in their testosterone levels, an endocrinological change that typically reflects pronounced social submission in humans and other animals. Participants were randomly assigned to either win or lose a rigged face-to-face competition with a confederate. Although no zero-order relationship between social anxiety and level of testosterone was observed, testosterone levels showed a pronounced drop among socially anxious men who lost the competition. No significant changes were observed in nonanxious men or in women. This research provides novel insight into the nature and consequences of social anxiety, and also illustrates the utility of integrating social psychological theory with endocrinological approaches to psychological science.

  16. Fast vigilance decrement in closed head injury patients as reflected by the mismatch negativity (MMN).

    Science.gov (United States)

    Kaipio, M L; Novitski, N; Tervaniemi, M; Alho, K; Ohman, J; Salonen, O; Näätänen, R

    2001-05-25

    Event-related potentials (ERPs) were measured from 24 chronic closed head injury (CHI) patients and 18 age- and education-matched controls. The oddball paradigm was applied while subjects were watching a silent movie. The standard (p=0.8) sound of 75 ms duration had a basic frequency of 500 Hz with harmonic partials of 1000 Hz and 1500 Hz, whereas these frequencies for the pitch deviant were each 10% higher. The frequencies of the duration deviant matched with those of the standard but was 25 ms in duration. The MMN (mismatch negativity), generated by the brain's automatic auditory change-detector mechanism, was elicited by both deviants. No significant differences in the MMN latency or amplitude for either pitch or duration deviants were found between the groups. However, the MMN amplitude for the pitch deviant decreased in the patient group during the experiment considerably faster than in controls, suggesting a faster vigilance decrement in the patients.

  17. Comparisons of PRD [power-reactivity-decrements] components for various EBR-II configurations

    International Nuclear Information System (INIS)

    Meneghetti, D.; Kucera, D.A.

    1986-01-01

    Comparison of detailed calculations of contributions by region and component of the power-reactivity-decrements (PRD) for four differing loading configurations of the Experimental Breeder Reactor-II (EBR-II) are given. The linear components and Doppler components are calculated. The non-linear (primarily subassembly bowing) components are deduced by differences relative to measured total PRD values. Variations in linear components range from about 10% to as much as about 100% depending upon the component. The deduced non-linear components differ both in magnitude and sign as functions of reactor power. Effects of differing assumptions of the nature of the fuel-to-clad interactions upon the PRD components are also calculated

  18. Age-related decrements in bone mineral density in women over 65

    Science.gov (United States)

    Steiger, P.; Cummings, S. R.; Black, D. M.; Spencer, N. E.; Genant, H. K.

    1992-01-01

    Age-related changes in bone density contribute to the risk of fractures. To describe the relationship between age and bone mass in elderly women, we studied a large cohort of women over age 65 years who were recruited from population-based lists in four cities in the United States. Bone density in g/cm2 was measured by single-photon absorptiometry (SPA) and dual x-ray absorptiometry (DXA) at the distal and proximal radius, the calcaneus, the lumbar spine, and the proximal femur. Centralized data collection was used to control data quality and consistency. We found a strong inverse relationship between bone density and age for most sites. Decrements in bone density between women aged 65-69 years and women 85 years and older exceeded 16% in all regions except the spine, where the difference between the two age groups was 6%. Ward's triangle and the calcaneus exhibited the largest decrements, with 26 and 21%, respectively. The estimates of annual changes in bone mineral density by linear regression at sites other than the spine ranged from -0.82% at the femoral neck and trochanter to -1.30% at Ward's triangle. Correlations between the different regions ranged from r = 0.51 between the proximal radius and Ward's triangle to r = 0.66 between the distal radius and calcaneus. We conclude that the inverse relationship between age and bone mass measured by absorptiometry techniques in white women continues into the ninth decade of life. The relationship is strongest for bone density of Ward's triangle and the calcaneus and weakest for the spine.

  19. Reward-based learning under hardware constraints-using a RISC processor embedded in a neuromorphic substrate.

    Science.gov (United States)

    Friedmann, Simon; Frémaux, Nicolas; Schemmel, Johannes; Gerstner, Wulfram; Meier, Karlheinz

    2013-01-01

    In this study, we propose and analyze in simulations a new, highly flexible method of implementing synaptic plasticity in a wafer-scale, accelerated neuromorphic hardware system. The study focuses on globally modulated STDP, as a special use-case of this method. Flexibility is achieved by embedding a general-purpose processor dedicated to plasticity into the wafer. To evaluate the suitability of the proposed system, we use a reward modulated STDP rule in a spike train learning task. A single layer of neurons is trained to fire at specific points in time with only the reward as feedback. This model is simulated to measure its performance, i.e., the increase in received reward after learning. Using this performance as baseline, we then simulate the model with various constraints imposed by the proposed implementation and compare the performance. The simulated constraints include discretized synaptic weights, a restricted interface between analog synapses and embedded processor, and mismatch of analog circuits. We find that probabilistic updates can increase the performance of low-resolution weights, a simple interface between analog synapses and processor is sufficient for learning, and performance is insensitive to mismatch. Further, we consider communication latency between wafer and the conventional control computer system that is simulating the environment. This latency increases the delay, with which the reward is sent to the embedded processor. Because of the time continuous operation of the analog synapses, delay can cause a deviation of the updates as compared to the not delayed situation. We find that for highly accelerated systems latency has to be kept to a minimum. This study demonstrates the suitability of the proposed implementation to emulate the selected reward modulated STDP learning rule. It is therefore an ideal candidate for implementation in an upgraded version of the wafer-scale system developed within the BrainScaleS project.

  20. Using rewards-based incentives to increase purchase of fruit and vegetables in lower-income households: design and start-up of a randomized trial.

    Science.gov (United States)

    Phipps, Etienne J; Wallace, Samantha L; Stites, Shana D; Uplinger, Nadine; Brook Singletary, S; Hunt, Lacy; Axelrod, Saul; Glanz, Karen; Braitman, Leonard E

    2013-05-01

    To report the design and baseline results of a rewards-based incentive to promote purchase of fruit and vegetables by lower-income households. A four-phase randomized trial with wait-listed controls. In a pilot study, despite inadequate study coupon use, purchases of fresh fruit (but not vegetables) increased, but with little maintenance. In the present study, credits on the study store gift card replace paper coupons and a tapering phase is added. The primary outcome is the number of servings of fresh and frozen fruit and vegetables purchased per week. A large full-service supermarket located in a predominantly minority community in Philadelphia, Pennsylvania, USA. Fifty-eight households, with at least one child living in the home. During the baseline period, households purchased an average of 3·7 servings of fresh vegetables and an average of less than 1 serving of frozen vegetables per week. Households purchased an average of 1·9 servings of fresh fruit per week, with little to no frozen fruit purchases. Overall, the range of fresh and frozen produce purchased during this pre-intervention period was limited. At baseline, produce purchases were small and of limited variety. The study will contribute to understanding the impact of financial incentives on increasing the purchases of healthier foods by lower-income populations.

  1. Hilbert-Twin – A Novel Hilbert Transform-Based Method To Compute Envelope Of Free Decaying Oscillations Embedded In Noise, And The Logarithmic Decrement In High-Resolution Mechanical Spectroscopy HRMS

    Directory of Open Access Journals (Sweden)

    Magalas L.B.

    2015-06-01

    Full Text Available In this work, we present a novel Hilbert-twin method to compute an envelope and the logarithmic decrement, δ, from exponentially damped time-invariant harmonic strain signals embedded in noise. The results obtained from five computing methods: (1 the parametric OMI (Optimization in Multiple Intervals method, two interpolated discrete Fourier transform-based (IpDFT methods: (2 the Yoshida-Magalas (YM method and (3 the classic Yoshida (Y method, (4 the novel Hilbert-twin (H-twin method based on the Hilbert transform, and (5 the conventional Hilbert transform (HT method are analyzed and compared. The fundamental feature of the Hilbert-twin method is the efficient elimination of intrinsic asymmetrical oscillations of the envelope, aHT (t, obtained from the discrete Hilbert transform of analyzed signals. Excellent performance in estimation of the logarithmic decrement from the Hilbert-twin method is comparable to that of the OMI and YM for the low- and high-damping levels. The Hilbert-twin method proved to be robust and effective in computing the logarithmic decrement and the resonant frequency of exponentially damped free decaying signals embedded in experimental noise. The Hilbert-twin method is also appropriate to detect nonlinearities in mechanical loss measurements of metals and alloys.

  2. Discovery of Variable Hydrogen Balmer Absorption Lines with Inverse Decrement in PG 1411+442

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xi-Heng; Pan, Xiang; Zhang, Shao-Hua; Sun, Lu-Ming; Ji, Tuo; Liu, Bo; Zhou, Hong-Yan [Polar Research Institute of China, Jinqiao Road 451, Shanghai 200136 (China); Wang, Jian-Guo [Yunnan Observatories, Chinese Academy of Sciences, Kunming, Yunnan 650011 (China); Yang, Chen-Wei; Jiang, Ning, E-mail: zhouhongyan@pric.org.cn, E-mail: shixiheng@pric.org.cn [Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China)

    2017-07-01

    We present new optical spectra of the well-known broad absorption line (BAL) quasar PG 1411+442, using the DBSP spectrograph at the Palomar 200 inch telescope in 2014 and 2017 and the YFOSC spectrograph at the Lijiang 2.4 m telescope in 2015. A blueshifted narrow absorption line system is clearly revealed in 2014 and 2015 consisting of hydrogen Balmer series and metastable He i lines. The velocity of these lines is similar to the centroid velocity of the UV BALs, suggesting that both originate from the outflow. The Balmer lines vary significantly between the two observations and vanished in 2017. They were also absent in the archived spectra obtained before 2001. The variation is thought to be driven by photoionization change. Besides, the absorption lines show inversed Balmer decrement, i.e., the apparent optical depths of higher-order Balmer absorption lines are larger than those of lower-order lines, which is inconsistent with the oscillator strengths of the transitions. We suggest that such anomalous line ratios can be naturally explained by the thermal structure of a background accretion disk, which allows the obscured part of the disk to contribute differently to the continuum flux at different wavelengths. High-resolution spectroscopic and photometric monitoring would be very useful to probe the structure of the accretion disk as well as the geometry and physical conditions of the outflow.

  3. Nebular dust and extinction in ionized nebulae i.. the Balmer decrement

    International Nuclear Information System (INIS)

    Mathis, J.S.

    1983-01-01

    Many astronomical objects contain plasma with internal or surrounding dust. The extinction of H II regions can be determined from the H#betta#/Hα flux ratio, and also from the H#betta#/radio fluxes. The two determinations almost always disagree by large factors (typically, approx.3), with the (H#betta#/Hα) extinction being smaller. This is shown to be a consequence of the albedo of dust at Hα being smaller than that of H#betta#, so that the destruction of Hα by dust is larger than for constant albedo. If the difference in albedo is ignored, one interprets the lower Hα flux as being caused by a small optical depth in dust. Simple models for the geometry of the dust and emitting gas are discussed: spherical models with dust mixed with the ionized gas, and also a slab of absorbing dust overlying the nebula. The two geometries give similar results for the Balmer decrements, so geometry does not strongly enter the final results. The conclusion that albedo (Hα) 8000 A). Recommendations for dereddening emission-line objects are presented and should be applicable to planetary nebulae, active galactic nuclei, or quasi-stellar objects as well as to H II regions

  4. High protein diets do not attenuate decrements in testosterone and IGF-I during energy deficit.

    Science.gov (United States)

    Henning, Paul C; Margolis, Lee M; McClung, James P; Young, Andrew J; Pasiakos, Stefan M

    2014-05-01

    Energy deficit (ED) diminishes fat-free mass (FFM) with concomitant reductions in anabolic hormone secretion. A modest increase in protein to recommended dietary allowance (RDA) levels during ED minimally attenuates decrements in insulin-like growth factor-I (IGF-I). The impact of dietary protein above the RDA on circulating anabolic hormones and their relationships with FFM in response to ED are not well described. Thirty-three adults were assigned diets providing protein at 0.8 (RDA), 1.6 (2×-RDA), and 2.4 (3×-RDA) g/kg/d for 31days. Testosterone, sex-hormone binding globulin (SHBG) and IGF-I system components were assessed after a 10-day period of weight-maintenance (WM) and after a 21-day period of ED (40%) achieved by an increase in energy expenditure and decreased energy intake. Associations between the change in FFM and anabolic hormone levels were determined. As compared to WM and regardless of dietary protein intake, total and free testosterone, total IGF-I, and acid-labile subunit decreased (Phormones or IGF-I system components measured. Changes in FFM in response to ED were negatively associated with acid-labile subunit (ALS) (r=-0.62, Phormone concentrations. Published by Elsevier Inc.

  5. Putting the brakes on the "drive to eat": Pilot effects of naltrexone and reward based eating on food cravings among obese women

    Science.gov (United States)

    Mason, Ashley E.; Laraia, Barbara; Daubenmier, Jennifer; Hecht, Frederick M.; Lustig, Robert H.; Puterman, Eli; Adler, Nancy; Dallman, Mary; Kiernan, Michaela; Gearhardt, Ashley N.; Epel, Elissa S.

    2015-01-01

    Purpose Obese individuals vary in their experience of food cravings and tendency to engage in reward-driven eating, both of which can be modulated by the neural reward system rather than physiological hunger. We examined two predictions in a sample of obese women: (1) whether opioidergic blockade reduced food-craving intensity, and (2) whether opioidergic blockade reduced an association between food-craving intensity and reward-driven eating, which is a trait-like index of three factors (lack of control over eating, lack of satiation, preoccupation with food). Methods Forty-four obese, pre-menopausal women completed the Reward-based Eating Drive (RED) scale at study start and daily food-craving intensity on 5 days on which they ingested either a pill-placebo (2 days), a 25mg naltrexone dose (1 day), or a standard 50mg naltrexone dose (2 days). Results Craving intensity was similar under naltrexone and placebo doses. The association between food-craving intensity and reward-driven eating significantly differed between placebo and 50mg naltrexone doses. Reward-driven eating and craving intensity were significantly positively associated under both placebo doses. As predicted, opioidergic blockade (for both doses 25mg and 50mg naltrexone) reduced this positive association between reward-driven eating and craving intensity to non-significance. Conclusions Opioidergic blockade did not reduce craving intensity; however, blockade reduced an association between trait-like reward-driven eating and daily food-craving intensity, and may help identify an important endophenotype within obesity. PMID:26164674

  6. [Multiple decrement tables of changes in the marital status of the population of Poland (1982-1984)].

    Science.gov (United States)

    Kedelski, M; Golata, E

    1986-01-01

    Official Polish data for the period 1982-1984 are used to construct multiple decrement tables of changes in marital status for the population of a hypothetical cohort over the course of its life history. The data are analyzed separately by sex with respect to the probabilities of change in marital status, the characteristics of the life cycle, and the expectation of life by marital status category. (SUMMARY IN ENG AND RUS)

  7. Supplemental Tyrosine and Vigilance Performance in a Normoxic Hypobaric Environment

    National Research Council Canada - National Science Library

    Maresh, Ryan

    2001-01-01

    .... The less control the individual has over these stresses, the greater the decrement. The decrease in performance, particularly mental performance, results from a depletion of catecholamines within the brain...

  8. Using multiple decrement models to estimate risk and morbidity from specific AIDS illnesses. Multicenter AIDS Cohort Study (MACS).

    Science.gov (United States)

    Hoover, D R; Peng, Y; Saah, A J; Detels, R R; Day, R S; Phair, J P

    A simple non-parametric approach is developed to simultaneously estimate net incidence and morbidity time from specific AIDS illnesses in populations at high risk for death from these illnesses and other causes. The disease-death process has four-stages that can be recast as two sandwiching three-state multiple decrement processes. Non-parametric estimation of net incidence and morbidity time with error bounds are achieved from these sandwiching models through modification of methods from Aalen and Greenwood, and bootstrapping. An application to immunosuppressed HIV-1 infected homosexual men reveals that cytomegalovirus disease, Kaposi's sarcoma and Pneumocystis pneumonia are likely to occur and cause significant morbidity time.

  9. 奖励式众筹平台与项目发起人的演化博弈%Analysis of the evolutionary game of reward-based crowdfunding platforms and entrepreneurs

    Institute of Scientific and Technical Information of China (English)

    邓必腾; 赵征

    2017-01-01

    To investigate the selection mechanism of the reward-based crowdfunding platform operation mode,a game model was developed by employing the evolutionary game theory.With this model the evolutionary dynamic stability of the selection for every stakeholder''s strategy was analyzed,and critical factors that determine the selection mechanism of the reward-based crowdfunding platform operation mode were explored by means of numerical simulation.The main result indicates that the key factor influencing the selection mechanism contains the following five dimensions: entrepreneurs'' demand for financing,crowdfunding platform service rates,service efficiency of the crowdfunding platform,opportunity cost of the crowdfunding platform to provide high quality services and government regulation of the reward-based crowdfunding market.%为研究奖励式众筹平台运作模式选择行为的决策机理,运用演化博弈理论的分析方法,构建奖励式众筹模式下奖励式众筹平台与项目发起人策略行为的演化博弈模型,对各利益主体策略的选择进行了演化动态稳定性分析,并通过数值仿真探求影响奖励式众筹平台运作模式选择的关键因素.研究表明:项目发起人的融资需求量,众筹平台收取的服务费率,众筹平台提供高服务的效率,众筹平台提供高服务的机会成本以及政府对众筹行业的监管程度是影响奖励式众筹平台运作模式的关键因素.

  10. Topographical distribution of decrements and recovery in muscarinic receptors from rat brains repeatedly exposed to sublethal doses of soman

    International Nuclear Information System (INIS)

    Churchill, L.; Pazdernik, T.L.; Jackson, J.L.; Nelson, S.R.; Samson, F.E.; McDonough, J.H. Jr.

    1984-01-01

    [3H]Quinuclidinyl benzilate binding to rat brain muscarinic receptors decreased after repeated exposure to soman, a potent organophosphorus cholinesterase inhibitor. The topographical distribution of this decrement was analyzed by quantitative receptor autoradiography. After 4 weeks of soman, three times a week, quinuclidinyl benzilate binding decreased to 67 to 80% of control in frontal and parietal cortex, caudate-putamen, lateral septum, hippocampal body, dentate gyrus, superior colliculus, nucleus of the fifth nerve, and central grey. Minor or no decreases were observed in thalamic or hypothalamic nuclei, reticular formation, pontine nuclei, inferior colliculus, nucleus of the seventh nerve, and cerebellum. Scatchard analyses of saturation curves using frontal cortex sections from soman-treated rats revealed a decrease in maximal quinuclidinyl benzilate binding from that in control rats and a return toward control levels by 24 days without any significant change in affinity. These brain areas showing significant decrements in muscarinic receptors recovered with a similar time course. An estimate of the time for 50% recovery for some of the brain areas was 14 days for superior colliculus, 16 days for cortex, and 19 days for hippocampal body. The application of quantitative receptor autoradiography to analyze receptor alterations has been valuable in localizing the telencephalon as a region more susceptible to change in receptor concentration

  11. Estimating increment-decrement life tables with multiple covariates from panel data: the case of active life expectancy.

    Science.gov (United States)

    Land, K C; Guralnik, J M; Blazer, D G

    1994-05-01

    A fundamental limitation of current multistate life table methodology-evident in recent estimates of active life expectancy for the elderly-is the inability to estimate tables from data on small longitudinal panels in the presence of multiple covariates (such as sex, race, and socioeconomic status). This paper presents an approach to such an estimation based on an isomorphism between the structure of the stochastic model underlying a conventional specification of the increment-decrement life table and that of Markov panel regression models for simple state spaces. We argue that Markov panel regression procedures can be used to provide smoothed or graduated group-specific estimates of transition probabilities that are more stable across short age intervals than those computed directly from sample data. We then join these estimates with increment-decrement life table methods to compute group-specific total, active, and dependent life expectancy estimates. To illustrate the methods, we describe an empirical application to the estimation of such life expectancies specific to sex, race, and education (years of school completed) for a longitudinal panel of elderly persons. We find that education extends both total life expectancy and active life expectancy. Education thus may serve as a powerful social protective mechanism delaying the onset of health problems at older ages.

  12. Topographical distribution of decrements and recovery in muscarinic receptors from rat brains repeatedly exposed to sublethal doses of soman

    Energy Technology Data Exchange (ETDEWEB)

    Churchill, L.; Pazdernik, T.L.; Jackson, J.L.; Nelson, S.R.; Samson, F.E.; McDonough, J.H. Jr.

    1984-08-01

    (3H)Quinuclidinyl benzilate binding to rat brain muscarinic receptors decreased after repeated exposure to soman, a potent organophosphorus cholinesterase inhibitor. The topographical distribution of this decrement was analyzed by quantitative receptor autoradiography. After 4 weeks of soman, three times a week, quinuclidinyl benzilate binding decreased to 67 to 80% of control in frontal and parietal cortex, caudate-putamen, lateral septum, hippocampal body, dentate gyrus, superior colliculus, nucleus of the fifth nerve, and central grey. Minor or no decreases were observed in thalamic or hypothalamic nuclei, reticular formation, pontine nuclei, inferior colliculus, nucleus of the seventh nerve, and cerebellum. Scatchard analyses of saturation curves using frontal cortex sections from soman-treated rats revealed a decrease in maximal quinuclidinyl benzilate binding from that in control rats and a return toward control levels by 24 days without any significant change in affinity. These brain areas showing significant decrements in muscarinic receptors recovered with a similar time course. An estimate of the time for 50% recovery for some of the brain areas was 14 days for superior colliculus, 16 days for cortex, and 19 days for hippocampal body. The application of quantitative receptor autoradiography to analyze receptor alterations has been valuable in localizing the telencephalon as a region more susceptible to change in receptor concentration.

  13. Effects of the NMDA receptor antagonist, D-CPPene, on sensitization to the operant decrement produced by naloxone in morphine-treated rats.

    Science.gov (United States)

    Bespalov, A Y; Medvedev, I O; Sukhotina, I A; Zvartau, E E

    2001-04-01

    Sensitization to the rate-decreasing effects of opioid antagonists induced by acute pretreatment with opioid agonists has been suggested to reflect initial changes in opioid systems that underlie physical dependence. Glutamate receptors are implicated in the development and expression of opioid dependence, and antagonists acting at the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors have been shown repeatedly to attenuate the severity of opioid withdrawal. The present study evaluated the ability of a competitive NMDA receptor antagonist, D-CPPene (SDZ EAA 494; 3-(2-carboxypiperazin-4-yl)-1-propenyl-1-phosphonic acid), to affect morphine-induced sensitization to naloxone in rats trained to lever-press on a multiple-trial, fixed-ratio 10 schedule of food reinforcement. D-CPPene (0.3-3 mg/kg) was administered either 4 h or 30 min prior to the test session. Morphine (10 mg/kg) or its vehicle was administered 4 h before naloxone challenge (0.3-3 mg/kg). D-CPPene failed to prevent morphine-induced potentiation of the naloxone-produced decrement in operant performance. Thus, these results suggest that agonist-induced sensitization to behavioral effects of opioid antagonists may be insensitive to NMDA receptor blockade.

  14. Risk of Adverse Health Outcomes & Decrements in Performance due to Inflight Medical Conditions: ExMC Pharmacy Research Plan

    Science.gov (United States)

    Antonsen, Erik

    2016-01-01

    The Exploration Medical Capabilities (ExMC) Element of NASA's Human Research Program is charged with identifying medical capabilities that can address the challenges of prevention, diagnosis, and treatment of disease and injuries that could occur during exploration missions beyond Earth's orbit. Faced with the obstacle of access to in-flight medical care, and limitations of vehicle space, time, and communications; it is necessary to prioritize what medical consumables are manifested for the flight, and which medical conditions are addressed. Studies of astronaut health establish the incidence of common and high risk medical conditions that require medical intervention during long-duration exploration missions. In 2000, the Institute of Medicine (IOM) convened a committee of experts, Committee on Creating a Vision for Space Medicine during Travel beyond Earth Orbit, to examine the issues surrounding astronaut health and safety for long duration space missions. Two themes run throughout the committee's final report: (1) that not enough is known about the risks to human health during long-duration missions beyond Earth's orbit or about what can effectively mitigate those risks to enable humans to travel and work safely in the environment of deep space and (2) that everything reasonable should be done to gain the necessary information before humans are sent on missions of space exploration (IOM, 2001). Although several spaceflight focused pharmaceutical research studies have been conducted, few have provided sufficient data regarding medication usage or potency changes during spaceflight. The Du pharmaceutical stability study assessed medications flown on space shuttles to and from the International Space Station (ISS) from 2006 until 2008; of which some medications were still viable beyond their expiration dates (Du et al, 2011). However, as with many spaceflight studies, the small 'n' associated with this study limits the ability to draw strong conclusions from it. Dr. Wotring and others have recently published articles containing information regarding medication usage, indications, and efficacy gleaned from spaceflight records (Wotring et al, 2015, 2016; Barger et al, 2014; Basner and Dinges, 2014). Although some conclusions can be drawn from these studies, the inability to fully quantify medication usage, indications, side effects, and effectiveness, limits insight as to which medications should be prioritized for further research.

  15. [Effect of vitamin D receptor gene polymorphism and lifestyle on bone mineral density and bone mineral density decrement rate].

    Science.gov (United States)

    Yamagata, Z; Miyamura, T; Iijima, S; Asaka, A

    1995-12-01

    The effects of genetic and environmental factors on bone mineral density (BMD) were investigated in 108 healthy Japanese women. Of the 108 subjects, BMD (from the second to forth lumbar vertebrae) was measured in 1992 in 103, in 1993 in 100, and in both years in 95 by dual energy X-ray absorptiometry. Vitamin D receptor (VDR) gene polymorphism in intron 8 was used as a genetic marker. Information on menstruation, health status, lifestyle, quantities of nutrient intake and frequencies of food intake was obtained by questionnaire. The frequency of allele B (825bp), whose polymerase chain reaction (PCR) products cannot be cut with BsmI, was 0.259 and the frequency of allele b (650bp), whose PCR products can be cut with BsmI, was 0.741. The subjects in our study obeyed the Hardy-Weinberg law. While the frequency of allele B was 0.448 in European whites as reported by Morrison et al, it was 0.259 in our Japanese subjects, suggesting a racial difference. Z score values (average value 0, standard deviation 1) increased in the order BB, Bb and bb. This result indicates that allele B is associated with the lower BMD in Japanese, as in European whites. The BMD decrement rate increased in the order bb, Bb and BB, indicating that VDR gene polymorphism may be a regulatory factor for losing BMD. Most of lifestyle variables, calcium intake and vitamin D intake were not correlated with BMD, but the food frequency score (which was defined as values weighted in each of three food categories obtained by factor analysis) was significantly correlated with BMD. Multiple regression analysis showed significant influences of years after menopause, the food frequency score and VDR genotype on BMD. VDR genotype and years after menopause influenced the BMD decrement rate significantly in multiple regression analysis. Neither a relationship between BMD and calcium intake nor between BMD and vitamin D intake by VDR genotype was found. These results suggest that the VDR gene is a genetic factor

  16. Source of the violet depression in carbon stars (a study of the Balmer decrement in carbon L.P.V.s)

    International Nuclear Information System (INIS)

    Orlati, M.A.

    1985-01-01

    In an effort to determine the nature of the agent(s) of the violet depression in N-type stars through the behavior of their Balmer decrement, slit spectrograms of two C, one CS, two S (all reported to have the violet depression) and one M type LPVs were repeatedly taken between May 1983 and November 1984. The observed phase related changes in the Balmer decrement exclude the possibility that the absorbers are circumstellar because the emission region in the best-observed star is seen to rise through the opacity source. The exact nature and number of kinds of absorbers remains to be determined

  17. Joint Economic Lot Sizing Optimization in a Supplier-Buyer Inventory System When the Supplier Offers Decremental Temporary Discounts

    Directory of Open Access Journals (Sweden)

    Diana Puspita Sari

    2012-02-01

    Full Text Available This research discusses mathematical models of joint economic lot size optimization in a supplier-buyer inventory system in a situation when the supplier offers decremental temporary discounts during a sale period. Here, the sale period consists of n phases and the phases of discounts offered descend as much as the number of phases. The highest discount will be given when orders are placed in the first phase while the lowest one will be given when they are placed in the last phase. In this situation, the supplier attempts to attract the buyer to place orders as early as possible during the sale period. The buyers will respon these offers by ordering a special quantity in one of the phase. In this paper, we propose such a forward buying model with discount-proportionally-distributed time phases. To examine the behaviour of the proposed model, we conducted numerical experiments. We assumed that there are three phases of discounts during the sale period. We then compared the total joint costs of special order placed in each phase for two scenarios. The first scenario is the case of independent situation – there is no coordination between the buyer and the supplie-, while the second scenario is the opposite one, the coordinated model. Our results showed the coordinated model outperform the independent model in terms of producing total joint costs. We finally conducted a sensitivity analyzis to examine the other behaviour of the proposed model. Keywords: supplier-buyer inventory system, forward buying model, decremental temporary discounts, joint economic lot sizing, optimization.

  18. Increments in insulin sensitivity during intensive treatment are closely correlated with decrements in glucocorticoid receptor mRNA in skeletal muscle from patients with Type II diabetes

    DEFF Research Database (Denmark)

    Vestergaard, H; Bratholm, P; Christensen, N J

    2001-01-01

    decreased significantly after intensive insulin treatment. A close correlation was found between increments in glucose uptake during intensive treatment and decrements in skeletal muscle total GCR mRNA (r=0.95, Pmultiple regression analysis), and between glucose uptake and alpha/alpha 2 GCR m RNA...

  19. Transient receptor potential cation channel A1 (TRPA1) mediates decrements in cardiac mechanical function and dysrhythmia caused by a single air pollution exposure in mice

    Science.gov (United States)

    This work, which will be presented at SOT 2014, demonstrates that a single exposure to either ozone or acrolein causes decrements in cardiac function and altered electrical activity (i.e. arrhythmia). The results suggest that this effect is mediated by the airway sensor TRPA1. ...

  20. A cGMP-dependent protein kinase gene, foraging, modifies habituation-like response decrement of the giant fiber escape circuit in Drosophila.

    Science.gov (United States)

    Engel, J E; Xie, X J; Sokolowski, M B; Wu, C F

    2000-01-01

    The Drosophila giant fiber jump-and-flight escape response is a model for genetic analysis of both the physiology and the plasticity of a sensorimotor behavioral pathway. We previously established the electrically induced giant fiber response in intact tethered flies as a model for habituation, a form of nonassociative learning. Here, we show that the rate of stimulus-dependent response decrement of this neural pathway in a habituation protocol is correlated with PKG (cGMP-Dependent Protein Kinase) activity and foraging behavior. We assayed response decrement for natural and mutant rover and sitter alleles of the foraging (for) gene that encodes a Drosophila PKG. Rover larvae and adults, which have higher PKG activities, travel significantly farther while foraging than sitters with lower PKG activities. Response decrement was most rapid in genotypes previously shown to have low PKG activities and sitter-like foraging behavior. We also found differences in spontaneous recovery (the reversal of response decrement during a rest from stimulation) and a dishabituation-like phenomenon (the reversal of response decrement evoked by a novel stimulus). This electrophysiological study in an intact animal preparation provides one of the first direct demonstrations that PKG can affect plasticity in a simple learning paradigm. It increases our understanding of the complex interplay of factors that can modulate the sensitivity of the giant fiber escape response, and it defines a new adult-stage phenotype of the foraging locus. Finally, these results show that behaviorally relevant neural plasticity in an identified circuit can be influenced by a single-locus genetic polymorphism existing in a natural population of Drosophila.

  1. A combination of routine blood analytes predicts fitness decrement in elderly endurance athletes.

    Directory of Open Access Journals (Sweden)

    Helmuth Haslacher

    Full Text Available Endurance sports are enjoying greater popularity, particularly among new target groups such as the elderly. Predictors of future physical capacities providing a basis for training adaptations are in high demand. We therefore aimed to estimate the future physical performance of elderly marathoners (runners/bicyclists using a set of easily accessible standard laboratory parameters. To this end, 47 elderly marathon athletes underwent physical examinations including bicycle ergometry and a blood draw at baseline and after a three-year follow-up period. In order to compile a statistical model containing baseline laboratory results allowing prediction of follow-up ergometry performance, the cohort was subgrouped into a model training (n = 25 and a test sample (n = 22. The model containing significant predictors in univariate analysis (alanine aminotransferase, urea, folic acid, myeloperoxidase and total cholesterol presented with high statistical significance and excellent goodness of fit (R2 = 0.789, ROC-AUC = 0.951±0.050 in the model training sample and was validated in the test sample (ROC-AUC = 0.786±0.098. Our results suggest that standard laboratory parameters could be particularly useful for predicting future physical capacity in elderly marathoners. It hence merits further research whether these conclusions can be translated to other disciplines or age groups.

  2. Measuring vigilance decrement using computer vision assisted eye tracking in dynamic naturalistic environments.

    Science.gov (United States)

    Bodala, Indu P; Abbasi, Nida I; Yu Sun; Bezerianos, Anastasios; Al-Nashash, Hasan; Thakor, Nitish V

    2017-07-01

    Eye tracking offers a practical solution for monitoring cognitive performance in real world tasks. However, eye tracking in dynamic environments is difficult due to high spatial and temporal variation of stimuli, needing further and thorough investigation. In this paper, we study the possibility of developing a novel computer vision assisted eye tracking analysis by using fixations. Eye movement data is obtained from a long duration naturalistic driving experiment. Source invariant feature transform (SIFT) algorithm was implemented using VLFeat toolbox to identify multiple areas of interest (AOIs). A new measure called `fixation score' was defined to understand the dynamics of fixation position between the target AOI and the non target AOIs. Fixation score is maximum when the subjects focus on the target AOI and diminishes when they gaze at the non-target AOIs. Statistically significant negative correlation was found between fixation score and reaction time data (r =-0.2253 and pdecrement, the fixation score decreases due to visual attention shifting away from the target objects resulting in an increase in the reaction time.

  3. The influence of wall orientation and exterior surface solar absorptivity on time lag and decrement factor in the Greek region

    Energy Technology Data Exchange (ETDEWEB)

    Kontoleon, K.J.; Eumorfopoulou, E.A. [Department of Civil Engineering, Laboratory of Building Construction and Physics, Aristotle University of Thessaloniki (A.U.Th.), Gr-541 24 Thessaloniki (Greece)

    2008-07-15

    The aim of this study is to determine how time lag and decrement factor are affected by wall orientation and exterior surface solar absorptivity, for specific climatic conditions. Their influence forms a non-sinusoidal periodical forcing function that simulates suitably the outdoor temperature fluctuations. This novel approach, allows the predictability of building's thermal response in an efficient way. The investigation is carried out for various insulated opaque wall formations comprising typical material elements, during the summer period in the mild Greek region. This study that allows proper building planning procedures, at the very early stages of the envelope design, presents great importance. The analysed configurations are assumed to have an orientation that corresponds to each compass point. In addition, the solar absorptivity of surface coatings is assumed to be varying from 0 to 1. The transient thermal analysis is obtained via a thermal circuit that models accurately the fundamental heat transfer mechanisms on both boundaries and through the multi-layered wall configurations. Moreover, the mathematical formulation and solution of this lumped model is achieved in discrete time steps by adopting the non-linear nodal method. The simulation results are focused on the single and combined effects of orientation and solar absorptivity on the dynamic thermal characteristics of various wall configurations. (author)

  4. Real time wide area radiation surveillance system (REWARD) based on 3d silicon and (CD,ZN)Te for neutron and gamma-ray detection

    Science.gov (United States)

    Disch, C.

    2014-09-01

    Mobile surveillance systems are used to find lost radioactive sources and possible nuclear threats in urban areas. The REWARD collaboration [1] aims to develop such a complete radiation monitoring system that can be installed in mobile or stationary setups across a wide area. The scenarios include nuclear terrorism threats, lost radioactive sources, radioactive contamination and nuclear accidents. This paper will show the performance capabilities of the REWARD system in different scnarios. The results include both Monte Carlo simulations as well as neutron and gamma-ray detection performances in terms of efficiency and nuclide identification. The outcomes of several radiation mapping survey with the entire REWARD system will also be presented.

  5. Decrements in health-related quality of life associated with gender nonconformity among U.S. adolescents and young adults.

    Science.gov (United States)

    Gordon, Allegra R; Krieger, Nancy; Okechukwu, Cassandra A; Haneuse, Sebastien; Samnaliev, Mihail; Charlton, Brittany M; Austin, S Bryn

    2017-08-01

    Gender nonconformity, that is, transgressing conventionally "masculine" vs. "feminine" characteristics, is often stigmatized. Stigmatization and discrimination are social stressors that raise risk of adverse mental and physical health outcomes and may drive health inequities. However, little is known about the relationship between such social stressors and health-related quality of life (HRQOL). This paper aimed to examine associations between perceived gender nonconformity and HRQOL in a cohort of U.S. adolescents and young adults. Using data from 8408 participants (18-31 years) in the U.S. Growing Up Today Study (93% white, 88% middle-to-high income), we estimated risk ratios (RRs) for the association of gender nonconformity (three levels: highly gender conforming, moderately conforming, and gender nonconforming) and HRQOL using the EuroQol questionnaire (EQ-5D-5L). Models were adjusted for demographic characteristics, including sexual orientation identity. Gender nonconformity was independently associated with increased risk of having problems with mobility [RR (95% confidence interval): 1.76 (1.16, 2.68)], usual activities [2.29 (1.67, 3.13)], pain or discomfort [1.59, (1.38, 1.83)], and anxiety or depression [1.72 (1.39, 2.13)], after adjusting for sexual orientation and demographic characteristics. Decrements in health utility by gender nonconformity were observed: compared to persons who were highly gender conforming, mean health utility was lower for the moderately gender conforming [beta (SE): -0.011 (.002)] and lowest for the most gender nonconforming [-0.034 (.005)]. In our study, HRQOL exhibited inequities by gender nonconformity. Future studies, including in more diverse populations, should measure the effect of gender-related harassment, discrimination, and violence victimization on health and HRQOL.

  6. Mice haploinsufficient for Map2k7, a gene involved in neurodevelopment and risk for schizophrenia, show impaired attention, a vigilance decrement deficit and unstable cognitive processing in an attentional task: impact of minocycline.

    Science.gov (United States)

    Openshaw, R L; Thomson, D M; Penninger, J M; Pratt, J A; Morris, B J

    2017-01-01

    Members of the c-Jun N-terminal kinase (JNK) family of mitogen-activated protein (MAP) kinases, and the upstream kinase MKK7, have all been strongly linked with synaptic plasticity and with the development of the neocortex. However, the impact of disruption of this pathway on cognitive function is unclear. In the current study, we test the hypothesis that reduced MKK7 expression is sufficient to cause cognitive impairment. Attentional function in mice haploinsufficient for Map2k7 (Map2k7 +/- mice) was investigated using the five-choice serial reaction time task (5-CSRTT). Once stable performance had been achieved, Map2k7 +/- mice showed a distinctive attentional deficit, in the form of an increased number of missed responses, accompanied by a more pronounced decrement in performance over time and elevated intra-individual reaction time variability. When performance was reassessed after administration of minocycline-a tetracycline antibiotic currently showing promise for the improvement of attentional deficits in patients with schizophrenia-signs of improvement in attentional performance were detected. Overall, Map2k7 haploinsufficiency causes a distinctive pattern of cognitive impairment strongly suggestive of an inability to sustain attention, in accordance with those seen in psychiatric patients carrying out similar tasks. This may be important for understanding the mechanisms of cognitive dysfunction in clinical populations and highlights the possibility of treating some of these deficits with minocycline.

  7. Using Real-Time Lexical Indicators to Detect Performance Decrements in Spaceflight Teams: A Methodology to Dynamically Monitor Cognitive, Emotional, and Social Mechanisms That Influence Performance

    Data.gov (United States)

    National Aeronautics and Space Administration — To date, we have collected data from HERA Campaign 1 (C1M1 – C1M4), HERA Campaign 2 (C2M1 – C2M4), and NEEMO18. The Year 1 effort was to conduct a proof-of-concept...

  8. Strategies for reward-based crowdfunding campaigns

    DEFF Research Database (Denmark)

    Kraus, Sascha; Richter, Christian; Brem, Alexander

    2016-01-01

    - cussions on crowdfunding. Furthermore, the analysis of success factors for crowdfunding initiatives adds to an emerging area of research and allows entrepreneurs to extract best practice examples for increasing the probability of successful crowdfunding projects under consideration of the key influencing...

  9. Anxiety and Academic Reading Performance among Malay ESL Learners

    Science.gov (United States)

    Mohd. Zin, Zuhana; Rafik-Galea, Shameem

    2010-01-01

    Research into the factors that contribute to reading performance decrement in L2 reading among ESL university students is still being extensively researched in the context of ELT. This is because successful academic performance is highly dependent on good reading ability. While it is widely accepted that poor reading performance is due to lack of…

  10. Delayed radiation injury of gut-exposed and gut-shielded mice. I. The decrement in resistance to continuous gamma-ray stress

    International Nuclear Information System (INIS)

    Spalding, J.F.; Archuleta, R.F.; London, J.E.; Prine, J.R.

    1977-02-01

    Two mouse strains (RF/J and C57B1/6J) were exposed to x-ray doses totaling 400, 800, or 1200 rad. Total doses were given in 200-rad fractions at 7-day intervals to the whole body, gut only, or gut shielded. Animals treated as above (conditioned) were divided into 2 groups to form a two-part investigation. X-ray-conditioned and control mice were subjected to a continuous gamma-ray stress (challenge exposure) 28 days after the last x-ray dose. Delayed injury was measured as a reduction in mean after-survival (MAS) time and was observed in whole-body, gut-conditioned, and gut-shielded groups. The cause of death was attributed to hemopoietic hypoplasia in all groups. MAS reduction in all conditioned groups in both strains was linear with dose within the dose range used. Delayed injury per volume dose (measured as a reduction in MAS) was independent of the tissue initially conditioned with an acute dose of x rays. Thus, delayed injury per unit weight of gut tissue exposed was equal to that of either whole-body or gut-shielded radiation injury. Comparative weight loss observations during the continuous gamma-ray challenge exposure revealed a decrement in metabolic processes associated with body weight maintenance. This decrement was seen in all x-ray-conditioned groups

  11. Cost sharing and HEDIS performance.

    Science.gov (United States)

    Chernew, Michael; Gibson, Teresa B

    2008-12-01

    Physicians, health plans, and health systems are increasingly evaluated and rewarded based on Health Plan Effectiveness Data and Information Set (HEDIS) and HEDIS-like performance measures. Concurrently, employers and health plans continue to try to control expenditures by increasing out-of-pocket costs for patients. The authors use fixed-effect logit models to assess how rising copayment rates for physician office visits and prescription drugs affect performance on HEDIS measures. Findings suggest that the increase in copayment rates lowers performance scores, demonstrating the connection between financial aspects of plan design and quality performance, and highlighting the potential weakness of holding plans and providers responsible for performance when payers and benefit plan managers also influence performance. Yet the effects are not consistent across all domains and, in many cases, are relatively modest in magnitude. This may reflect the HEDIS definitions and suggests that more sensitive measures may capture the impact of benefit design changes on performance.

  12. Influence of internal and external boundary conditions on the decrement factor and time lag heat flux of building walls in steady periodic regime

    International Nuclear Information System (INIS)

    Mazzeo, D.; Oliveti, G.; Arcuri, N.

    2016-01-01

    Highlights: • Dynamic behaviour of building walls subjected to sinusoidal and actual loadings. • The joint action of more temperature and heat flux loadings has been considered. • Dynamic parameters were defined by the internal and external fluctuating heat flux. • Use of the Total Harmonic Distortion to determine the number of harmonics required. • Study of the influence of external and internal loadings on dynamic parameters. - Abstract: The dynamic behaviour of opaque components of the building envelope in steady periodic regime is investigated using parameters defined by the fluctuating heat flux that is transferred in the wall. The use of the heat flux allows for the joint action of the loadings that characterise both the outdoor environment and the indoor air-conditioned environment to be taken into account. The analysis was developed in sinusoidal conditions to determine the frequency response of the wall and in non-sinusoidal conditions to identify the actual dynamic behaviour of the wall. The use of non-dimensional periodic thermal transmittance is proposed for the sinusoidal analysis in order to evaluate the decrement factor and the time lag that the heat flux undergoes in crossing the wall as well as the efficiency of heat storage. In the presence of non-sinusoidal loadings, the identification of the dynamic behaviour of the wall is obtained using several dynamic parameters: the decrement factor in terms of energy, defined as the ratio between the energy in a semi-period entering and exiting the wall; the decrement factor and the time lag in terms of heat flux, considering the maximum peak and the minimum peak. These parameters allow for the identification of how the form of the heat flux trend crossing the wall is modified. The number of harmonics to be considered for an accurate representation of heat fluxes is determined by means of the introduction of the Total Harmonic Distortion (THD), which quantifies the distortion of a non

  13. Spanish genetic admixture is associated with larger V(O2) max decrement from sea level to 4338 m in Peruvian Quechua.

    Science.gov (United States)

    Brutsaert, Tom D; Parra, Esteban J; Shriver, Mark D; Gamboa, Alfredo; Palacios, Jose-Antonio; Rivera, Maria; Rodriguez, Ivette; León-Velarde, Fabiola

    2003-08-01

    Quechua in the Andes may be genetically adapted to altitude and able to resist decrements in maximal O2 consumption in hypoxia (DeltaVo2 max). This hypothesis was tested via repeated measures of Vo2 max (sea level vs. 4338 m) in 30 men of mixed Spanish and Quechua origins. Individual genetic admixture level (%Spanish ancestry) was estimated by using ancestry-informative DNA markers. Genetic admixture explained a significant proportion of the variability in DeltaVo2 max after control for covariate effects, including sea level Vo2 max and the decrement in arterial O2 saturation measured at Vo2 max (DeltaSpO2 max) (R2 for admixture and covariate effects approximately 0.80). The genetic effect reflected a main effect of admixture on DeltaVo2 max (P = 0.041) and an interaction between admixture and DeltaSpO2 max (P = 0.018). Admixture predicted DeltaVo2 max only in subjects with a large DeltaSpO2 max (P = 0.031). In such subjects, DeltaVo2 max was 12-18% larger in a subgroup of subjects with high vs. low Spanish ancestry, with least squares mean values (+/-SE) of 739 +/- 71 vs. 606 +/- 68 ml/min, respectively. A trend for interaction (P = 0.095) was also noted between admixture and the decrease in ventilatory threshold at 4338 m. As previously, admixture predicted DeltaVo2 max only in subjects with a large decrease in ventilatory threshold. These findings suggest that the genetic effect on DeltaVo2 max depends on a subject's aerobic fitness. Genetic effects may be more important (or easier to detect) in athletic subjects who are more likely to show gas-exchange impairment during exercise. The results of this study are consistent with the evolutionary hypothesis and point to a better gas-exchange system in Quechua.

  14. The Combined Effect of Cold and Moisture on Manual Performance.

    Science.gov (United States)

    Ray, Matthew; Sanli, Elizabeth; Brown, Robert; Ennis, Kerri Ann; Carnahan, Heather

    2018-02-01

    Objective The aim of this study was to investigate the combined effect of cold and moisture on manual performance and tactile sensitivity. Background People working in the ocean environment often perform manual work in cold and wet conditions. Although the independent effects of cold and moisture on hand function are known, their combined effect has not been investigated. Method Participants completed sensory (Touch-Test, two-point discrimination) and motor (Purdue Pegboard, Grooved Pegboard, reef knot untying) tests in the following conditions: dry hand, wet hand, cold hand, and cold and wet hand. Results For the Purdue Pegboard and knot untying tasks, the greatest decrement in performance was observed in the cold-and-wet-hand condition, whereas the decrements seen in the cold-hand and wet-hand conditions were similar. In the Grooved Pegboard task, the performance decrements exhibited in the cold-and-wet-hand condition and the cold-hand condition were similar, whereas no decrement was observed in the wet-hand condition. Tactile sensitivity was reduced in the cold conditions for the Touch-Test but not the two-point discrimination test. The combined effect of cold and moisture led to the largest performance decrements except when intrinsic object properties helped with grasp maintenance. The independent effects of cold and moisture on manual performance were comparable. Application Tools and equipment for use in the cold ocean environment should be designed to minimize the effects of cold and moisture on manual performance by including object properties that enhance grasp maintenance and minimize the fine-dexterity requirements.

  15. Muscular activity and torque of the foot dorsiflexor muscles during decremental isometric test: A cross-sectional study.

    Science.gov (United States)

    Ruiz-Muñoz, Maria; González-Sánchez, Manuel; Martín-Martín, Jaime; Cuesta-Vargas, Antonio I

    2017-06-01

    To analyse the torque variation level that could be explained by the muscle activation (EMG) amplitude of the three major foot dorsiflexor muscles (tibialis anterior (TA), extensor digitorum longus (EDL), extensor hallucis longus (EHL)) during isometric foot dorsiflexion at different intensities. In a cross-sectional study, forty-one subjects performed foot dorsiflexion at 100%, 75%, 50% and 25% of maximal voluntary contractions (MVC) with the hip and knee flexed 90° and the ankle in neutral position (90° between leg and foot). Three foot dorsiflexions were performed for each intensity. Outcome variables were: maximum (100% MVC) and relative torque (75%, 50%, 25% MVC), maximum and relative EMG amplitude. A linear regression analysis was calculated for each intensity of the isometric foot dorsiflexion. The degree of torque variation (dependent variable) from the independent variables explain (EMG amplitude of the three major foot dorsiflexor muscles) the increases when the foot dorsiflexion intensity is increased, with values of R 2 that range from 0.194 (during 25% MVC) to 0.753 (during 100% MVC). The reliability of the outcome variables was excellent. The EMG amplitude of the three main foot dorsiflexors exhibited more variance in the dependent variable (torque) when foot dorsiflexion intensity increases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Estimation of the vibration decrement of an offshore wind turbine support structure caused by its interaction with soil

    Energy Technology Data Exchange (ETDEWEB)

    Versteijlen, W.G; Metrikine, A.; Hoving, J.S.; Smidt, E.H.; De Vries, W.E. [Department Hydraulic Engineering, Faculty of Civil Engineering and Geosciences, Delft University of Technology TUD, Delft (Netherlands)

    2012-01-15

    In today's cutting costs environment in the offshore wind industry, significant achievements can be made with a better assessment of dynamic soil-pile interaction. Of the main damping mechanisms active at an OWT (offshore wind turbine), least is known about soil damping. The values for this contribution used in the industry today - mostly calculated analogously to a study performed in 1980 - are expected to be on the low side. More research on the topic is recommended. Presence of more damping than currently assumed, would signify that the (often) design driving fatigue damage accumulation is lower than assumed. This would justify designing more light-weight structures using less construction steel, or allowing for longer (insured) OWT lifetimes then the now applied 20 years. Both these measures significantly decrease costs of offshore wind. This paper evaluates measured signals of twelve 'rotorstop' - test on an OWT at Dong Energy owned - Burbo Banks windfarm. The vibration decay was measured with an accelerometer and strain gauges along the tower. A simplistic analytical model has been developed enabling analyses of the measured signals. Two main modal shapes were identified with similar shape, but deviating amplitudes in the soil profile. The large difference in damping that exists between the vibrations of these modes is attributed to the difference in influence that the soil can have on these vibrations. The found effect of soil on the damping of this particular OWT is significantly larger than the order of magnitude used in the industry today.

  17. DNA polymerase β decrement triggers death of olfactory bulb cells and impairs olfaction in a mouse model of Alzheimer's disease.

    Science.gov (United States)

    Misiak, Magdalena; Vergara Greeno, Rebeca; Baptiste, Beverly A; Sykora, Peter; Liu, Dong; Cordonnier, Stephanie; Fang, Evandro F; Croteau, Deborah L; Mattson, Mark P; Bohr, Vilhelm A

    2017-02-01

    Alzheimer's disease (AD) involves the progressive degeneration of neurons critical for learning and memory. In addition, patients with AD typically exhibit impaired olfaction associated with neuronal degeneration in the olfactory bulb (OB). Because DNA base excision repair (BER) is reduced in brain cells during normal aging and AD, we determined whether inefficient BER due to reduced DNA polymerase-β (Polβ) levels renders OB neurons vulnerable to degeneration in the 3xTgAD mouse model of AD. We interrogated OB histopathology and olfactory function in wild-type and 3xTgAD mice with normal or reduced Polβ levels. Compared to wild-type control mice, Polβ heterozygous (Polβ +/- ), and 3xTgAD mice, 3xTgAD/Polβ +/- mice exhibited impaired performance in a buried food test of olfaction. Polβ deficiency did not affect the proliferation of OB neural progenitor cells in the subventricular zone. However, numbers of newly generated neurons were reduced by approximately 25% in Polβ +/- and 3xTgAD mice, and by over 60% in the 3xTgAD/Polβ +/- mice compared to wild-type control mice. Analyses of DNA damage and apoptosis revealed significantly greater degeneration of OB neurons in 3xTgAD/Polβ +/- mice compared to 3xTgAD mice. Levels of amyloid β-peptide (Aβ) accumulation in the OB were similar in 3xTgAD and 3xTgAD/Polβ +/- mice, and cultured Polβ-deficient neurons exhibited increased vulnerability to Aβ-induced death. Olfactory deficit is an early sign in human AD, but the mechanism is not yet understood. Our findings in a new AD mouse model demonstrate that diminution of BER can endanger OB neurons, and suggest a mechanism underlying early olfactory impairment in AD. © 2016 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  18. PERFORMANCE

    Directory of Open Access Journals (Sweden)

    M Cilli

    2014-10-01

    Full Text Available This study aimed to investigate the kinematic and kinetic changes when resistance is applied in horizontal and vertical directions, produced by using different percentages of body weight, caused by jumping movements during a dynamic warm-up. The group of subjects consisted of 35 voluntary male athletes (19 basketball and 16 volleyball players; age: 23.4 ± 1.4 years, training experience: 9.6 ± 2.7 years; height: 177.2 ± 5.7 cm, body weight: 69.9 ± 6.9 kg studying Physical Education, who had a jump training background and who were training for 2 hours, on 4 days in a week. A dynamic warm-up protocol containing seven specific resistance movements with specific resistance corresponding to different percentages of body weight (2%, 4%, 6%, 8%, 10% was applied randomly on non consecutive days. Effects of different warm-up protocols were assessed by pre-/post- exercise changes in jump height in the countermovement jump (CMJ and the squat jump (SJ measured using a force platform and changes in hip and knee joint angles at the end of the eccentric phase measured using a video camera. A significant increase in jump height was observed in the dynamic resistance warm-up conducted with different percentages of body weight (p 0.05. In jump movements before and after the warm-up, while no significant difference between the vertical ground reaction forces applied by athletes was observed (p>0.05, in some cases of resistance, a significant reduction was observed in hip and knee joint angles (p<0.05. The dynamic resistance warm-up method was found to cause changes in the kinematics of jumping movements, as well as an increase in jump height values. As a result, dynamic warm-up exercises could be applicable in cases of resistance corresponding to 6-10% of body weight applied in horizontal and vertical directions in order to increase the jump performance acutely.

  19. Setting individualized positive end-expiratory pressure level with a positive end-expiratory pressure decrement trial after a recruitment maneuver improves oxygenation and lung mechanics during one-lung ventilation.

    Science.gov (United States)

    Ferrando, Carlos; Mugarra, Ana; Gutierrez, Andrea; Carbonell, Jose Antonio; García, Marisa; Soro, Marina; Tusman, Gerardo; Belda, Francisco Javier

    2014-03-01

    We investigated whether individualized positive end-expiratory pressure (PEEP) improves oxygenation, ventilation, and lung mechanics during one-lung ventilation compared with standardized PEEP. Thirty patients undergoing thoracic surgery were randomly allocated to the study or control group. Both groups received an alveolar recruitment maneuver at the beginning and end of one-lung ventilation. After the alveolar recruitment maneuver, the control group had their lungs ventilated with a 5 cm·H2O PEEP, while the study group had their lungs ventilated with an individualized PEEP level determined by a PEEP decrement trial. Arterial blood samples, lung mechanics, and volumetric capnography were recorded at multiple timepoints throughout the procedure. The individualized PEEP values in study group were higher than the standardized PEEP values (10 ± 2 vs 5 cm·H2O; P decrement trial than with a standardized 5 cm·H2O of PEEP.

  20. The effects of stereotypes and observer pressure on athletic performance.

    Science.gov (United States)

    Krendl, Anne; Gainsburg, Izzy; Ambady, Nalini

    2012-02-01

    Although the effects of negative stereotypes and observer pressure on athletic performance have been well researched, the effects of positive stereotypes on performance, particularly in the presence of observers, is not known. In the current study, White males watched a video either depicting Whites basketball players as the best free throwers in the NBA (positive stereotype), Black basketball players as the best free throwers in the NBA (negative stereotype), or a neutral sports video (control). Participants then shot a set of free throws, during which half the participants were also videotaped (observer condition), whereas the other half were not (no observer condition). Results demonstrated that positive stereotypes improved free throw performance, but only in the no observer condition. Interestingly, observer pressure interacted with the positive stereotype to lead to performance decrements. In the negative stereotype condition, performance decrements were observed both in the observer and no observer conditions.

  1. A Multiple Decrement Life Table Reveals That Host Plant Resistance and Parasitism Are Major Causes of Mortality for the Wheat Stem Sawfly.

    Science.gov (United States)

    Buteler, Micaela; Peterson, Robert K D; Hofland, Megan L; Weaver, David K

    2015-12-01

    This study investigated the dynamics of parasitism, host plant resistance, pathogens, and predation on the demography of wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), developing in susceptible (hollow stem) and resistant (solid stem) wheat hosts. This study is also the first to investigate the prevalence and impact of cannibalism on wheat stem sawfly mortality. Wheat stem sawflies were sampled in two commercial wheat fields over 4 yr from the egg stage through adult emergence, and multiple decrement life tables were constructed and analyzed. Cannibalism, host plant resistance, or unknown factors were the most prevalent factors causing egg mortality. Summer mortality of prediapause larvae ranged from 28 to 84%, mainly due to parasitism by Bracon cephi (Gahan) and Bracon lissogaster Muesebeck, cannibalism, and host plant resistance. Winter mortality ranged from 6 to 54% of the overwintering larvae, mainly due to unknown factors or pathogens. Cannibalism is a major cause of irreplaceable mortality because it is absolute, with only a single survivor in every multiple infested stem. Subsequent to obligate cannibalism, mortality of feeding larvae due to host plant resistance was lower in hollow stem wheat than in solid stem wheat. Mortality from host plant resistance was largely irreplaceable. Irreplaceable mortality due to parasitoids was greater in hollow stem wheat than in solid stem wheat. Host plant resistance due to stem solidness and parasitism in hollow stems cause substantial mortality in populations of actively feeding larvae responsible for all crop losses. Therefore, enhancing these mortality factors is vital to effective integrated pest management of wheat stem sawfly. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Site Characterization in the Urban Area of Tijuana, B. C., Mexico by Means of: H/V Spectral Ratios, Spectral Analysis of Surface Waves, and Random Decrement Method

    Science.gov (United States)

    Tapia-Herrera, R.; Huerta-Lopez, C. I.; Martinez-Cruzado, J. A.

    2009-05-01

    Results of site characterization for an experimental site in the metropolitan area of Tijuana, B. C., Mexico are presented as part of the on-going research in which time series of earthquakes, ambient noise, and induced vibrations were processed with three different methods: H/V spectral ratios, Spectral Analysis of Surface Waves (SASW), and the Random Decrement Method, (RDM). Forward modeling using the wave propagation stiffness matrix method (Roësset and Kausel, 1981) was used to compute the theoretical SH/P, SV/P spectral ratios, and the experimental H/V spectral ratios were computed following the conventional concepts of Fourier analysis. The modeling/comparison between the theoretical and experimental H/V spectral ratios was carried out. For the SASW method the theoretical dispersion curves were also computed and compared with the experimental one, and finally the theoretical free vibration decay curve was compared with the experimental one obtained with the RDM. All three methods were tested with ambient noise, induced vibrations, and earthquake signals. Both experimental spectral ratios obtained with ambient noise as well as earthquake signals agree quite well with the theoretical spectral ratios, particularly at the fundamental vibration frequency of the recording site. Differences between the fundamental vibration frequencies are evident for sites located at alluvial fill (~0.6 Hz) and at sites located at conglomerate/sandstones fill (0.75 Hz). Shear wave velocities for the soft soil layers of the 4-layer discrete soil model ranges as low as 100 m/s and up to 280 m/s. The results with the SASW provided information that allows to identify low velocity layers, not seen before with the traditional seismic methods. The damping estimations obtained with the RDM are within the expected values, and the dominant frequency of the system also obtained with the RDM correlates within the range of plus-minus 20 % with the one obtained by means of the H/V spectral

  3. Age-Related Changes in Brain Activation Underlying Single- and Dual-Task Performance: Visuomanual Drawing and Mental Arithmetic

    Science.gov (United States)

    Van Impe, A.; Coxon, J. P.; Goble, D. J.; Wenderoth, N.; Swinnen, S. P.

    2011-01-01

    Depending on task combination, dual-tasking can either be performed successfully or can lead to performance decrements in one or both tasks. Interference is believed to be caused by limitations in central processing, i.e. structural interference between the neural activation patterns associated with each task. In the present study, single- and…

  4. Can we detect non-functional overreaching in young elite soccer players and middle-long distance runners using field performance tests?

    NARCIS (Netherlands)

    Schmikli, S. L.; Brink, M. S.; de Vries, W. R.; Backx, F. J. G.

    Objective To study whether field performance tests can make a valid distinction between non-functionally overreaching (NFO) athletes and control athletes. Design Monthly field performance tests were used to determine a performance decrement (PD) throughout a season. Athletes with a minimum of 1

  5. Six-dimensional muon beam cooling using a homogeneous absorber: Concepts, beam dynamics, cooling decrements, and equilibrium emittances in a helical dipole channel

    Directory of Open Access Journals (Sweden)

    Yaroslav Derbenev

    2005-04-01

    describing six-dimensional cooling in this channel are also derived, including explicit expressions for cooling decrements and equilibrium emittances.

  6. Habitability and Performance Issues for Long Duration Space Flights

    Science.gov (United States)

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

    1997-01-01

    Advancing technology, coupled with the desire to explore space has resulted in increasingly longer manned space missions. Although the Long Duration Space Flights (LDSF) have provided a considerable amount of scientific research on human ability to function in extreme environments, findings indicate long duration missions take a toll on the individual, both physiologically and psychologically. These physiological and psychological issues manifest themselves in performance decrements; and could lead to serious errors endangering the mission, spacecraft and crew. The purpose of this paper is to document existing knowledge of the effects of LDSF on performance, habitability, and workload and to identify and assess potential tools designed to address these decrements as well as propose an implementation plan to address the habitability, performance and workload issues.

  7. Mild Traumatic Brain Injury and Dynamic Simulated Shooting Performance

    Science.gov (United States)

    2016-02-01

    differences between tasks. All pairwise comparisons were adjusted with a Sidak correction for multiple comparisons. TLX scores 0 5 10 15 20 25 30 35...research at multiple sites. Specific to the question of MTBI-related balance, we recommend that future studies seek, when feasible, to quantify body sway...higher ratings of perceived workload. In addition, the alternate analyses yielded some preliminary evidence of shooting performance decrements

  8. Human Performance in Continuous Operations. Volume 3. Technical Documentation

    Science.gov (United States)

    1980-03-01

    completed for the U. S. Commander, V Corps. Artillery, by Manning (1978). Manning collected information which bears on the following three questions: 0 Can...performance data were not collected in these pre- liminary studies. Field Studies of Continuous Tank OperationsLI __ _ _ __ _ _ _ To simulate a combat...on routine, monotonous tasks tends A show rapid and severe decrement after peri- odk of more than 24 hours without sleep. I Increasing task complexity

  9. Treadmill Exercise with Increased Body Loading Enhances Post Flight Functional Performance

    Science.gov (United States)

    Bloomberg, J. J.; Batson, C. D.; Buxton, R. E.; Feiveson, A. H.; Kofman, I. S.; Laurie, S.; Lee, S. M. C.; Miller, C. A.; Mulavara, A. P.; Peters, B. T.; hide

    2014-01-01

    The goals of the Functional Task Test (FTT) study were to determine the effects of space flight on functional tests that are representative of high priority exploration mission tasks and to identify the key underlying physiological factors that contribute to decrements in performance. Ultimately this information will be used to assess performance risks and inform the design of countermeasures for exploration class missions. We have previously shown that for Shuttle, ISS and bed rest subjects functional tasks requiring a greater demand for dynamic control of postural equilibrium (i.e. fall recovery, seat egress/obstacle avoidance during walking, object translation, jump down) showed the greatest decrement in performance. Functional tests with reduced requirements for postural stability (i.e. hatch opening, ladder climb, manual manipulation of objects and tool use) showed little reduction in performance. These changes in functional performance were paralleled by similar decrements in sensorimotor tests designed to specifically assess postural equilibrium and dynamic gait control. The bed rest analog allows us to investigate the impact of axial body unloading in isolation on both functional tasks and on the underlying physiological factors that lead to decrements in performance and then compare them with the results obtained in our space flight study. These results indicate that body support unloading experienced during space flight plays a central role in postflight alteration of functional task performance. Given the importance of body-support loading we set out to determine if there is a relationship between the load experienced during inflight treadmill exercise (produced by a harness and bungee system) and postflight functional performance. ISS crewmembers (n=13) were tested using the FTT protocol before and after 6 months in space. Crewmembers were tested three times before flight, and on 1, 6, and 30 days after landing. To determine how differences in body

  10. Reward-based Crowdfunding : Case ASMO-charger

    OpenAIRE

    Tonttila, Juho

    2016-01-01

    This thesis focuses on studying a rising global financing phenomenon called crowdfunding. The aim of this work is to find out what kind of a financing method crowdfunding is and how it can be used by individuals and start-up companies for gathering capital. Work also focuses on clarifying what exactly crowdfunding is and how does it work because the subject is quite new and the information about it is still scarce. The work itself is based on literal sources and analysis of the informatio...

  11. Evolving Neural Turing Machines for Reward-based Learning

    DEFF Research Database (Denmark)

    Greve, Rasmus Boll; Jacobsen, Emil Juul; Risi, Sebastian

    2016-01-01

    An unsolved problem in neuroevolution (NE) is to evolve artificial neural networks (ANN) that can store and use information to change their behavior online. While plastic neural networks have shown promise in this context, they have difficulties retaining information over longer periods of time...... version of the double T-Maze, a complex reinforcement-like learning problem. In the T-Maze learning task the agent uses the memory bank to display adaptive behavior that normally requires a plastic ANN, thereby suggesting a complementary and effective mechanism for adaptive behavior in NE....

  12. The Effects of Noise on Performance

    Science.gov (United States)

    1989-06-01

    Performance" by C. S. Harris in W. D. Ward (Ed.) Proceedings of the International Congress on Noise as a Public Health Problem (EPA 550/9-73-008), 1973, U.S...141a duration tracking for primary task. Suggestion 35 at 1-9s Intervals Secondary task-response ot addivity for secondary 55 time task decrement. 95...In G. Rossi (Ed.) Pro eedings of the Fourth International Congress on Noise as a Public Health Problem, Vol- 2. Milan: Centro Ricerche e Studi

  13. Differentiating anxiety forms and their role in academic performance from primary to secondary school

    OpenAIRE

    Carey, E; Devine, A; Hill, F; Szűcs, Denes

    2017-01-01

    INTRODUCTION: Individuals with high levels of mathematics anxiety are more likely to have other forms of anxiety, such as general anxiety and test anxiety, and tend to have some math performance decrement compared to those with low math anxiety. However, it is unclear how the anxiety forms cluster in individuals, or how the presence of other anxiety forms influences the relationship between math anxiety and math performance. METHOD: We measured math anxiety, test anxiety, general anxiety and ...

  14. 2014 Behavioral Health and Performance Standing Review Panel

    Science.gov (United States)

    Steinberg, Susan; Leon, Gloria; Dimsdale, Joel; Balkin, Thomas; Bono, Joyce; Caldwell, John; Joiner, Thomas; Paulus, Martin; Zaccaro, Stephen

    2015-01-01

    The 2014 Behavioral Health and Performance (BHP) Standing Review Panel (from here on referred to as the SRP) met for a site visit in Houston, TX on December 17 - 18, 2014. The SRP reviewed the updated research plan for the Risk of Performance Errors Due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness, and Work Overload (Sleep Risk) and also received a status update on the Risk of Adverse Behavioral Conditions and Psychiatric Disorders (BMed Risk) and the Risk of Performance Decrements Due to Inadequate Cooperation, Coordination, Communication, and Psychosocial Adaptation within a Team (Team Risk).

  15. Lorazepam induces multiple disturbances in selective attention: attentional overload, decrement in target processing efficiency, and shifts in perceptual discrimination and response bias.

    Science.gov (United States)

    Michael, George Andrew; Bacon, Elisabeth; Offerlin-Meyer, Isabelle

    2007-09-01

    There is a general consensus that benzodiazepines affect attentional processes, yet only few studies have tried to investigate these impairments in detail. The purpose of the present study was to investigate the effects of a single dose of Lorazepam on performance in a target cancellation task with important time constraints. We measured correct target detections and correct distractor rejections, misses and false positives. The results show that Lorazepam produces multiple kinds of shifts in performance, which suggests that it impairs multipLe processes: (a) the evolution of performance over time was not the same between the placebo and the Lorazepam groups, with the Lorazepam affecting performance quite early after the beginning of the test. This is suggestive of a depletion of attentional resources during sequential attentional processing; (b) Lorazepam affected differently target and distractor processing, with target detection being the most impaired; (c) misses were more frequent under Lorazepam than under placebo, but no such difference was observed as far as false positives were concerned. Signal detection analyses showed that Lorazepam (d) decreased perceptual discrimination, and (e) reliably increased response bias. Our results bring new insights on the multiple effects of Lorazepam on selective attention which, when combined, may have deleterious effects on human performance.

  16. Effects of objectifying gaze on female cognitive performance: The role of flow experience and internalization of beauty ideals.

    Science.gov (United States)

    Guizzo, Francesca; Cadinu, Mara

    2017-06-01

    Although previous research has demonstrated that objectification impairs female cognitive performance, no research to date has investigated the mechanisms underlying such decrement. Therefore, we tested the role of flow experience as one mechanism leading to performance decrement under sexual objectification. Gaze gender was manipulated by having male versus female experimenters take body pictures of female participants (N = 107) who then performed a Sustained Attention to Response Task. As predicted, a moderated mediation model showed that under male versus female gaze, higher internalization of beauty ideals was associated with lower flow, which in turn decreased performance. The implications of these results are discussed in relation to objectification theory and strategies to prevent sexually objectifying experiences. © 2016 The British Psychological Society.

  17. 3α-androstanediol, but not testosterone, attenuates age-related decrements in cognitive, anxiety, and depressive behavior of male rats

    Directory of Open Access Journals (Sweden)

    Cheryl A Frye

    2010-04-01

    Full Text Available Some hippocampally-influenced affective and/or cognitive processes decline with aging. The role of androgens in this process is of interest. Testosterone (T is aromatized to estrogen, and reduced to dihydrotestosterone (DHT, which is converted to 5α-androstane, 3α, 17α-diol (3α-diol. To determine the extent to which some age-related decline in hippocampally-influenced behaviors may be due to androgens, we examined the effects of variation in androgen levels due to age, gonadectomy, and androgen replacement on cognitive (inhibitory avoidance, Morris water maze and affective (defensive freezing, forced swim behavior among young (4-months, middle-aged (13-months, and aged (24-months male rats. Plasma and hippocampal levels of androgens were determined. In experiment 1, comparisons were made between 4-, 13-, and 24-month old rats that were intact or gonadectomized (GDX and administered a T-filled or empty silastic capsule. There was age-related decline in performance of the inhibitory avoidance, water maze, defensive freezing, and forced swim tasks, and hippocampal 3α-diol levels. Chronic, long-term (1-4 weeks T-replacement reversed the effects of GDX in 4- and 13-month old, but not 24-month old, rats in the inhibitory avoidance task. Experiments 2 and 3 assessed whether acute subcutaneous T or 3α-diol, respectively, could reverse age-associated decline in performance. 3α-diol, but not T, compared to vehicle, improved performance in the inhibitory avoidance, water maze, forced swim, and defensive freezing tasks, irrespective of age. Thus, age is associated with a decrease in 3α-diol production and 3α-diol administration reinstates cognitive and affective performance of aged male rats.

  18. Performance in a 12-hour, 300-rad profile

    International Nuclear Information System (INIS)

    Yochmowitz, M.G.; Brown, G.C.

    1977-01-01

    A discrete behavioral task was initiated to study the effects of a 300-rad variable dose rate exposure profile upon positively (food reward) and negatively (mild shock) reinforced groups of primates. Animals performed the task for 12 h. Performance decrements were readily apparent in 2 of 8 shock and 2 of 7 food animals, while delayed reaction times were found in 3 of 8 shock and 3 of 7 food animals. Of the 7 food animals, 4 exhibited emesis, while 1 of 8 shock animals vomited. Such information is useful to military planners who need guidelines to indicate potential aircrew nuclear vulnerability and survivability

  19. Operational stressors on physical performance in special operators and countermeasures to improve performance: a review of the literature.

    Science.gov (United States)

    O'Hara, Reginald; Henry, Amy; Serres, Jennifer; Russell, Dawn; Locke, Robert

    2014-01-01

    Military training in elite warfighters (e.g., U.S. Army Rangers, Navy SEALs, and U.S. Air Force Battlefield Airmen) is challenging and requires mental and physical capabilities that are akin to that of professional athletes. However, unlike professional athletes, the competitive arena is the battlefield, with winning and losing replaced by either life or death. The rigors of both physical training and prolonged deployments without adequate rest and food intake can compromise physical performance. Therefore, the primary purpose of this effort was to identify occupational stressors on the physical performance of Special Operators during training and while on missions. The secondary purpose was to suggest specific countermeasures to reduce or prevent significant decrements in physical performance and reduce musculoskeletal injuries. A search of the literature for 2000?2012 was performed using the Air Force Institute of Technology search engines (i.e., PubMed and ProQuest). There were 29 articles located and selected that specifically addressed the primary and secondary purposes of this literature review. The remaining 32 of 61 referenced articles were reviewed after initial review of the primary literature. This review indicates that operational stress (e.g., negative energy balance, high-energy expenditure, sleep deprivation, environmental extremes, heavy load carriage, etc.) associated with rigorous training and sustained operations negatively affects hormonal levels, lean muscle mass, and physical performance of Special Operators. The number of musculoskeletal injuries also increases as a result of these stressors. Commanders may use simple field tests to assess physical decrements before and during deployment to effectively plan for missions. Specific countermeasures for these known decrements are lacking in the scientific literature. Therefore, future researchers should focus on studying specific physical training programs, equipment, and other methods to

  20. The effects of monitoring environment on problem-solving performance.

    Science.gov (United States)

    Laird, Brian K; Bailey, Charles D; Hester, Kim

    2018-01-01

    While effective and efficient solving of everyday problems is important in business domains, little is known about the effects of workplace monitoring on problem-solving performance. In a laboratory experiment, we explored the monitoring environment's effects on an individual's propensity to (1) establish pattern solutions to problems, (2) recognize when pattern solutions are no longer efficient, and (3) solve complex problems. Under three work monitoring regimes-no monitoring, human monitoring, and electronic monitoring-114 participants solved puzzles for monetary rewards. Based on research related to worker autonomy and theory of social facilitation, we hypothesized that monitored (versus non-monitored) participants would (1) have more difficulty finding a pattern solution, (2) more often fail to recognize when the pattern solution is no longer efficient, and (3) solve fewer complex problems. Our results support the first two hypotheses, but in complex problem solving, an interaction was found between self-assessed ability and the monitoring environment.

  1. CD21+ (B2 antigen+) cell decrement and CD4+CD29+ (helper-inducer) cell increment suggest an activation of cell immune reactivity in multiple sclerosis.

    Science.gov (United States)

    Gambi, D; Porrini, A M; Giampietro, A; Macor, S

    1991-08-01

    Two-color flow cytometric analysis on peripheral blood lymphocytes of 35 untreated multiple sclerosis (MS) patients, 17 other medical disease (OMD) patients and 14 healthy control (HC) subjects was performed to evaluate the levels of different T and B cell subpopulations. In MS patients we observed an increase in CD4+CD29+ helper-inducer cells but this increase was not related to the different phases of the disease. We hypothesize that this change is related to the reduction of CD21+ cells expressing B2 antigen, a 140 kDa molecule disappearing after B cell activation. An increased level of CD4+CD45RA- (helper-inducer-like cells) and a reduction of CD4+CD29- (suppressor-inducer-like cells) were also present in our patients. These findings demonstrate an immune 'disequilibrium' in MS, which is linked with an increased level of CD25+ cells expressing the interleukin-2 (IL-2) receptor. IL-2, besides being a T cell growth factor, is also a B cell growth factor. These data let us hypothesize that an activation of the immune response is present in MS.

  2. Predicting High-Power Performance in Professional Cyclists.

    Science.gov (United States)

    Sanders, Dajo; Heijboer, Mathieu; Akubat, Ibrahim; Meijer, Kenneth; Hesselink, Matthijs K

    2017-03-01

    To assess if short-duration (5 to ~300 s) high-power performance can accurately be predicted using the anaerobic power reserve (APR) model in professional cyclists. Data from 4 professional cyclists from a World Tour cycling team were used. Using the maximal aerobic power, sprint peak power output, and an exponential constant describing the decrement in power over time, a power-duration relationship was established for each participant. To test the predictive accuracy of the model, several all-out field trials of different durations were performed by each cyclist. The power output achieved during the all-out trials was compared with the predicted power output by the APR model. The power output predicted by the model showed very large to nearly perfect correlations to the actual power output obtained during the all-out trials for each cyclist (r = .88 ± .21, .92 ± .17, .95 ± .13, and .97 ± .09). Power output during the all-out trials remained within an average of 6.6% (53 W) of the predicted power output by the model. This preliminary pilot study presents 4 case studies on the applicability of the APR model in professional cyclists using a field-based approach. The decrement in all-out performance during high-intensity exercise seems to conform to a general relationship with a single exponential-decay model describing the decrement in power vs increasing duration. These results are in line with previous studies using the APR model to predict performance during brief all-out trials. Future research should evaluate the APR model with a larger sample size of elite cyclists.

  3. Thoracic Hemisection in Rats Results in Initial Recovery Followed by a Late Decrement in Locomotor Movements, with Changes in Coordination Correlated with Serotonergic Innervation of the Ventral Horn

    Science.gov (United States)

    Leszczyńska, Anna N.; Majczyński, Henryk; Wilczyński, Grzegorz M.; Sławińska, Urszula; Cabaj, Anna M.

    2015-01-01

    Lateral thoracic hemisection of the rodent spinal cord is a popular model of spinal cord injury, in which the effects of various treatments, designed to encourage locomotor recovery, are tested. Nevertheless, there are still inconsistencies in the literature concerning the details of spontaneous locomotor recovery after such lesions, and there is a lack of data concerning the quality of locomotion over a long time span after the lesion. In this study, we aimed to address some of these issues. In our experiments, locomotor recovery was assessed using EMG and CatWalk recordings and analysis. Our results showed that after hemisection there was paralysis in both hindlimbs, followed by a substantial recovery of locomotor movements, but even at the peak of recovery, which occurred about 4 weeks after the lesion, some deficits of locomotion remained present. The parameters that were abnormal included abduction, interlimb coordination and speed of locomotion. Locomotor performance was stable for several weeks, but about 3–4 months after hemisection secondary locomotor impairment was observed with changes in parameters, such as speed of locomotion, interlimb coordination, base of hindlimb support, hindlimb abduction and relative foot print distance. Histological analysis of serotonergic innervation at the lumbar ventral horn below hemisection revealed a limited restoration of serotonergic fibers on the ipsilateral side of the spinal cord, while on the contralateral side of the spinal cord it returned to normal. In addition, the length of these fibers on both sides of the spinal cord correlated with inter- and intralimb coordination. In contrast to data reported in the literature, our results show there is not full locomotor recovery after spinal cord hemisection. Secondary deterioration of certain locomotor functions occurs with time in hemisected rats, and locomotor recovery appears partly associated with reinnervation of spinal circuitry by serotonergic fibers. PMID

  4. Performance Enhancements Under Dual-task Conditions

    Science.gov (United States)

    Kramer, A. F.; Wickens, C. D.; Donchin, E.

    1984-01-01

    Research on dual-task performance has been concerned with delineating the antecedent conditions which lead to dual-task decrements. Capacity models of attention, which propose that a hypothetical resource structure underlies performance, have been employed as predictive devices. These models predict that tasks which require different processing resources can be more successfully time shared than tasks which require common resources. The conditions under which such dual-task integrality can be fostered were assessed in a study in which three factors likely to influence the integrality between tasks were manipulated: inter-task redundancy, the physical proximity of tasks and the task relevant objects. Twelve subjects participated in three experimental sessions in which they performed both single and dual-tasks. The primary task was a pursuit step tracking task. The secondary tasks required the discrimination between different intensities or different spatial positions of a stimulus. The results are discussed in terms of a model of dual-task integrality.

  5. Cognitive Performance in Operational Environments

    Science.gov (United States)

    Russo, Michael; McGhee, James; Friedler, Edna; Thomas, Maria

    2005-01-01

    Optimal cognition during complex and sustained operations is a critical component for success in current and future military operations. "Cognitive Performance, Judgment, and Decision-making" (CPJD) is a newly organized U.S. Army Medical Research and Materiel Command research program focused on sustaining operational effectiveness of Future Force Warriors by developing paradigms through which militarily-relevant, higher-order cognitive performance, judgment, and decision-making can be assessed and sustained in individuals, small teams, and leaders of network-centric fighting units. CPJD evaluates the impact of stressors intrinsic to military operational environments (e.g., sleep deprivation, workload, fatigue, temperature extremes, altitude, environmental/physiological disruption) on military performance, evaluates noninvasive automated methods for monitoring and predicting cognitive performance, and investigates pharmaceutical strategies (e.g., stimulant countermeasures, hypnotics) to mitigate performance decrements. This manuscript describes the CPJD program, discusses the metrics utilized to relate militarily applied research findings to academic research, and discusses how the simulated combat capabilities of a synthetic battle laboratory may facilitate future cognitive performance research.

  6. Health impact from lead: IQ decrement

    Energy Technology Data Exchange (ETDEWEB)

    Easterly, C

    1994-07-01

    The effects of lead, once it is in the body, are the same no matter how it enters. Exposure to lead is especially dangerous for unborn children, with high levels associated with premature birth and low birth weight. Young children are at risk because they swallow lead when they put toys or other objects soiled with lead-containing dirt in their mouths. A greater proportion of the lead ingested by children enters their bodies than enters the bodies of adults. For infants and young children, lead exposure has been shown in some studies to decrease intelligence (IQ) scores, slow growth, and cause hearing problems. These effects can last as children get older and can be permanent. Realistic risk assessment for lead-induced neurobehavioral deficit in environmentally exposed children must stem from consistent results from independent studies, as well as the documentation of dose-response relationships. At present, studies investigating such effects have not been definitive. However, taken as a whole, there is growing support for the absence of a threshold for adverse effects in exposed children. Summary of selected recent studies and the obtained data are analyzed.

  7. Health impact from lead: IQ decrement

    International Nuclear Information System (INIS)

    Easterly, C.

    1994-01-01

    The effects of lead, once it is in the body, are the same no matter how it enters. Exposure to lead is especially dangerous for unborn children, with high levels associated with premature birth and low birth weight. Young children are at risk because they swallow lead when they put toys or other objects soiled with lead-containing dirt in their mouths. A greater proportion of the lead ingested by children enters their bodies than enters the bodies of adults. For infants and young children, lead exposure has been shown in some studies to decrease intelligence (IQ) scores, slow growth, and cause hearing problems. These effects can last as children get older and can be permanent. Realistic risk assessment for lead-induced neurobehavioral deficit in environmentally exposed children must stem from consistent results from independent studies, as well as the documentation of dose-response relationships. At present, studies investigating such effects have not been definitive. However, taken as a whole, there is growing support for the absence of a threshold for adverse effects in exposed children. Summary of selected recent studies and the obtained data are analyzed

  8. DUST EXTINCTION FROM BALMER DECREMENTS OF STAR-FORMING GALAXIES AT 0.75 {<=} z {<=} 1.5 WITH HUBBLE SPACE TELESCOPE/WIDE-FIELD-CAMERA 3 SPECTROSCOPY FROM THE WFC3 INFRARED SPECTROSCOPIC PARALLEL SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez, A.; Siana, B.; Masters, D. [Department of Physics and Astronomy, University of California Riverside, Riverside, CA 92521 (United States); Henry, A. L.; Martin, C. L. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Scarlata, C.; Bedregal, A. G. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Malkan, M.; Ross, N. R. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095 (United States); Atek, H.; Colbert, J. W. [Spitzer Science Center, Caltech, Pasadena, CA 91125 (United States); Teplitz, H. I.; Rafelski, M. [Infrared Processing and Analysis Center, Caltech, Pasadena, CA 91125 (United States); McCarthy, P.; Hathi, N. P.; Dressler, A. [Observatories of the Carnegie Institution for Science, Pasadena, CA 91101 (United States); Bunker, A., E-mail: albertod@ucr.edu [Department of Physics, Oxford University, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom)

    2013-02-15

    Spectroscopic observations of H{alpha} and H{beta} emission lines of 128 star-forming galaxies in the redshift range 0.75 {<=} z {<=} 1.5 are presented. These data were taken with slitless spectroscopy using the G102 and G141 grisms of the Wide-Field-Camera 3 (WFC3) on board the Hubble Space Telescope as part of the WFC3 Infrared Spectroscopic Parallel survey. Interstellar dust extinction is measured from stacked spectra that cover the Balmer decrement (H{alpha}/H{beta}). We present dust extinction as a function of H{alpha} luminosity (down to 3 Multiplication-Sign 10{sup 41} erg s{sup -1}), galaxy stellar mass (reaching 4 Multiplication-Sign 10{sup 8} M {sub Sun }), and rest-frame H{alpha} equivalent width. The faintest galaxies are two times fainter in H{alpha} luminosity than galaxies previously studied at z {approx} 1.5. An evolution is observed where galaxies of the same H{alpha} luminosity have lower extinction at higher redshifts, whereas no evolution is found within our error bars with stellar mass. The lower H{alpha} luminosity galaxies in our sample are found to be consistent with no dust extinction. We find an anti-correlation of the [O III] {lambda}5007/H{alpha} flux ratio as a function of luminosity where galaxies with L {sub H{alpha}} < 5 Multiplication-Sign 10{sup 41} erg s{sup -1} are brighter in [O III] {lambda}5007 than H{alpha}. This trend is evident even after extinction correction, suggesting that the increased [O III] {lambda}5007/H{alpha} ratio in low-luminosity galaxies is likely due to lower metallicity and/or higher ionization parameters.

  9. Performance Trends During Sleep Deprivation on a Tilt-Based Control Task.

    Science.gov (United States)

    Bolkhovsky, Jeffrey B; Ritter, Frank E; Chon, Ki H; Qin, Michael

    2018-07-01

    Understanding human behavior under the effects of sleep deprivation allows for the mitigation of risk due to reduced performance. To further this goal, this study investigated the effects of short-term sleep deprivation using a tilt-based control device and examined whether existing user models accurately predict targeting performance. A task in which the user tilts a surface to roll a ball into a target was developed to examine motor performance. A model was built to predict human performance for this task under various levels of sleep deprivation. Every 2 h, 10 subjects completed the task until they reached 24 h of wakefulness. Performance measurements of this task, which were based on Fitts' law, included movement time, task throughput, and time intercept. The model predicted significant performance decrements over the 24-h period with an increase in movement time (R2 = 0.61), a decrease in throughput (R2 = 0.57), and an increase in time intercept (R2 = 0.60). However, it was found that in experimental trials there was no significant change in movement time (R2 = 0.11), throughput (R2 = 0.15), or time intercept (R2 = 0.27). The results found were unexpected as performance decrement is frequently reported during sleep deprivation. These findings suggest a reexamination of the initial thought of sleep loss leading to a decrement in all aspects of performance.Bolkovsky JB, Ritter FE, Chon KH, Qin M. Performance trends during sleep deprivation on a tilt-based control task. Aerosp Med Hum Perform. 2018; 89(7):626-633.

  10. Functional Task Test: 1. Sensorimotor changes Associated with Postflight Alterations in Astronaut Functional Task Performance

    Science.gov (United States)

    Bloomberg, J. J.; Arzeno, N. H.; Buxton, R. E.; Feiveson, A. H.; Kofman, I. S.; Lee, S. M. C.; Miller, C. A.; Mulavara, A. P.; Platts, S. H.; Peters, B. T.; hide

    2011-01-01

    Space flight is known to cause alterations in multiple physiological systems including changes in sensorimotor, cardiovascular, and neuromuscular systems. These changes may affect a crewmember s ability to perform critical mission tasks immediately after landing on a planetary surface. The overall goal of this project is to determine the effects of space flight on functional tests that are representative of high priority exploration mission tasks and to identify the key underlying physiological factors that contribute to decrements in performance. This presentation will focus on the sensorimotor contributions to postflight functional performance.

  11. Mortalidade diferencial por causas, São Paulo, Brasil, 1970: tábuas de vida de múltiplo decremento Mortality differentials classified according to cause of death, S. Paulo, Brazil, 1970: multiple decrement life tables

    Directory of Open Access Journals (Sweden)

    Sabina Léa Davidson Gotlieb

    1981-08-01

    Full Text Available Foram feitas considerações sobre tábua de vida de múltiplo decremento, com o objetivo de avaliar a magnitude da atuação de alguns grupos de agravos à saúde nas probabilidades de morte, de sobrevivência e nas esperanças de vida dos residentes no município de São Paulo (Brasil, em 1970. A esperança de vida ao nascer foi igual a 60,12 anos no sexo masculino e 67,21 anos no sexo feminino. Os principais grupos de doenças em função dos ganhos que propiciariam à esperança de vida ao nascer, caso não tivessem sido fator de risco de morte, foram: no sexo masculino - cardiovasculares; infecciosas e parasitárias; acidentes, envenenamentos e violências e os tumores malignos; no sexo feminino - cardiovasculares; infecciosas e parasitárias; tumores malignos e os acidentes, envenenamentos e violências. Levantou-se a hipótese de que o padrão de mortalidade no município de São Paulo, em 1970, refletiria a existência de problemas de saúde de uma população formada por setores distintos onde coexistiriam condições típicas adversas à saúde, ora de regiões consideradas desenvolvidas, ora de regiões em desenvolvimento.General considerations about multiple decrement life tables are made to evaluate the impact of some diseases and other causes of death on the probabilities of death and survival and on the life expectancy of the inhabitants of the City of S. Paulo, Brazil, in 1970. The male life expectancy calculated was 60.12 years, and the female, 67.21. The main groups of causes of death, classified by the gains, were: for males - cardiovascular diseases, infectious and parasitic diseases, accidents, poisonings and violences and neoplasms; for women - cardiovascular diseases, infectious and parasitic diseases, neoplasms and accidents, poisonings, and violence. A dichotomous population could be considered as an explanatory hypothesis for the pattern of mortality prevailling in 1970 in S. Paulo; that is, the patterns probably

  12. Effect of milk on team sport performance after exercise-induced muscle damage.

    Science.gov (United States)

    Cockburn, Emma; Bell, Phillip G; Stevenson, Emma

    2013-08-01

    Exercise-induced muscle damage (EIMD) leads to increases in intramuscular proteins observed in the blood stream and delayed onset of muscle soreness, but crucial for athletes are the decrements in muscle performance observed. Previous research has demonstrated that carbohydrate-protein supplements limit these decrements; however, they have primarily used isokinetic dynamometry, which has limited applicability to dynamic sport settings. Therefore, the aim of this study was to investigate the effects of a carbohydrate-protein milk supplement consumed after muscle-damaging exercise on performance tests specific to field-based team sports. Two independent groups of seven males consumed either 500 mL of milk or a control immediately after muscle-damaging exercise. Passive and active delayed onset of muscle soreness, creatine kinase, myoglobin, countermovement jump height, reactive strength index, 15-m sprint, and agility time were assessed before and 24, 48, and 72 h after EIMD. The Loughborough Intermittent Shuttle Test was also performed before and 48 h after EIMD. At 48 h, milk had a possible benefit for limiting increases in 10-m sprint time and a likely benefit of attenuating increases in mean 15-m sprint time during the Loughborough Intermittent Shuttle Test. At 72 h, milk had a possible benefit for limiting increases in 15-m sprint time and a likely benefit for the attenuation of increases in agility time. All other effects for measured variables were unclear. The consumption of milk limits decrements in one-off sprinting and agility performance and the ability to perform repeated sprints during the physiological simulation of field-based team sports.

  13. Relationship Between Skating Economy and Performance During a Repeated-Shift Test in Elite and Subelite Ice Hockey Players.

    Science.gov (United States)

    Lamoureux, Nicholas R; Tomkinson, Grant R; Peterson, Benjamin J; Fitzgerald, John S

    2018-04-01

    Lamoureux, NR, Tomkinson, GR, Peterson, BJ, and Fitzgerald, JS. Relationship between skating economy and performance during a repeated-shift test in elite and subelite ice hockey players. J Strength Cond Res 32(4): 1109-1113, 2018-The purpose of this study was to determine the importance of skating economy to fatigue during repeated high-intensity efforts of a simulated ice hockey shift. Forty-five collegiate and Junior A male ice hockey players (aged 18-24 years) performed a continuous graded exercise test using a skate treadmill. Breath-by-breath data for oxygen consumption (V[Combining Dot Above]O2) and respiratory exchange ratio were collected and used to derive energy expenditure (EE) averaged over the final 10 seconds of each stage. Economy was determined as the slope of the regression line relating V[Combining Dot Above]O2 and EE against skating speed separately. Participants also completed 8 bouts of maximal ice skating through a course designed to simulate typical shift, with timing gates determining first half, second half, and total fatigue decrement, calculated by a percent decrement score. Partial correlation was used to determine the association between economy measures and decrement during the repeated-shift test. Twenty-six participants met inclusion criteria and were included in data analysis. Skating economy measures (both relative V[Combining Dot Above]O2 and EE) were very likely moderate positive correlates of total fatigue decrement (r [95% confidence interval]: V[Combining Dot Above]O2, 0.46 [0.09, 0.72] and EE, 0.44, [0.06, 0.71]) but not with first or second gate decrement. Our results indicate that skating economy plays an important role in fatigue resistance over repeated on-ice sprints designed to simulate a typical shift. This supports the use of technical skating coaching and training techniques to enhance skating economy as a means of improving ice hockey performance.

  14. Isolated effects of peripheral arm and central body cooling on arm performance.

    Science.gov (United States)

    Giesbrecht, G G; Wu, M P; White, M D; Johnston, C E; Bristow, G K

    1995-10-01

    Whole body cooling impairs manual arm performance. The independent contributions of local (peripheral) and/or whole body (central) cooling are not known. Therefore, a protocol was developed in which the arm and the rest of the body could be independently cooled. Biceps temperature (Tmus), at a depth of 20 mm, and esophageal temperature (Tes) were measured. Six subjects were immersed to the clavicles in a tank (body tank) of water under 3 conditions: 1) cold body-cold arm (CB-CA); 2) warm body-cold arm (WB-CA); and 3) cold body-warm arm (CB-WA). In the latter two conditions, subjects placed their dominant arm in a separate (arm) tank. Water temperature (Tw) in each tank was independently controlled. In conditions requiring cold body and/or cold arm, Tw in the appropriate tanks was 8 degrees C. In conditions requiring warm body and/or warm arm, Tw in the appropriate tanks was adjusted between 29 and 38 degrees C to maintain body/arm temperature at baseline values. A battery of 6 tests, requiring fine or gross motor movements, were performed immediately before immersion and after 15, 45, and 70 minutes of immersion. In CB-CA, Tes decreased from an average of 37.2 to 35.6 degrees C and Tmus decreased from 34.6 to 22.0 degrees C. In WB-CA, Tmus decreased to 18.1 degrees C (Tes = 37.1 degrees C), and in CB-WA, Tes decreased to 35.8 degrees C (Tmus = 34.5 degrees C). By the end of immersion, there were significant decrements (43-85%) in the performance of all tests in CB-CA and WB-CA (p body and/or the arm elicits large decrements in finger, hand and arm performance. The decrements are due almost entirely to the local effects of arm tissue cooling.

  15. Heat stress, gastrointestinal permeability and interleukin-6 signaling - Implications for exercise performance and fatigue.

    Science.gov (United States)

    Vargas, Nicole; Marino, Frank

    2016-01-01

    Exercise in heat stress exacerbates performance decrements compared to normothermic environments. It has been documented that the performance decrements are associated with reduced efferent drive from the central nervous system (CNS), however, specific factors that contribute to the decrements are not completely understood. During exertional heat stress, blood flow is preferentially distributed away from the intestinal area to supply the muscles and brain with oxygen. Consequently, the gastrointestinal barrier becomes increasingly permeable, resulting in the release of lipopolysaccharides (LPS, endotoxin) into the circulation. LPS leakage stimulates an acute-phase inflammatory response, including the release of interleukin (IL)-6 in response to an increasingly endotoxic environment. If LPS translocation is too great, heat shock, neurological dysfunction, or death may ensue. IL-6 acts initially in a pro-inflammatory manner during endotoxemia, but can attenuate the response through signaling the hypothalamic pituitary adrenal (HPA)-axis. Likewise, IL-6 is believed to be a thermoregulatory sensor in the gut during the febrile response, hence highlighting its role in periphery - to - brain communication. Recently, IL-6 has been implicated in signaling the CNS and influencing perceptions of fatigue and performance during exercise. Therefore, due to the cascade of events that occur during exertional heat stress, it is possible that the release of LPS and exacerbated response of IL-6 contributes to CNS modulation during exertional heat stress. The purpose of this review is to evaluate previous literature and discuss the potential role for IL-6 during exertional heat stress to modulate performance in favor of whole body preservation.

  16. The effects of practice with MP3 players on driving performance.

    Science.gov (United States)

    Chisholm, S L; Caird, J K; Lockhart, J

    2008-03-01

    This study examined the effects of repeated iPod interactions on driver performance to determine if performance decrements decreased with practice. Nineteen younger drivers (mean age=19.4, range 18-22) participated in a seven session study in the University of Calgary Driving Simulator (UCDS). Drivers encountered a number of critical events on the roadways while interacting with an iPod including a pedestrian entering the roadway, a vehicle pullout, and a lead vehicle braking. Measures of hazard response, vehicle control, eye movements, and secondary task performance were analyzed. Increases in perception response time (PRT) and collisions were found while drivers were performing the difficult iPod tasks, which involved finding a specific song within the song titles menu. Over the course of the six experimental sessions, driving performance improved in all conditions. Difficult iPod interactions significantly increased the amount of visual attention directed into the vehicle above that of the baseline condition. With practice, slowed responses to driving hazards while interacting with the iPod declined somewhat, but a decrement still remained relative to the baseline condition. The multivariate results suggest that access to difficult iPod tasks while vehicles are in motion should be curtailed.

  17. Cold acclimation and cognitive performance: A review.

    Science.gov (United States)

    Jones, Douglas M; Bailey, Stephen P; Roelands, Bart; Buono, Michael J; Meeusen, Romain

    2017-12-01

    Athletes, occupational workers, and military personnel experience cold temperatures through cold air exposure or cold water immersion, both of which impair cognitive performance. Prior work has shown that neurophysiological pathways may be sensitive to the effects of temperature acclimation and, therefore, cold acclimation may be a potential strategy to attenuate cold-induced cognitive impairments for populations that are frequently exposed to cold environments. This review provides an overview of studies that examine repeated cold stress, cold acclimation, and measurements of cognitive performance to determine whether or not cold acclimation provides beneficial protection against cold-induced cognitive performance decrements. Studies included in this review assessed cognitive measures of reaction time, attention, logical reasoning, information processing, and memory. Repeated cold stress, with or without evidence of cold acclimation, appears to offer no added benefit of improving cognitive performance. However, research in this area is greatly lacking and, therefore, it is difficult to draw any definitive conclusions regarding the use of cold acclimation to improve cognitive performance during subsequent cold exposures. Given the current state of minimal knowledge on this topic, athletes, occupational workers, and military commands looking to specifically enhance cognitive performance in cold environments would likely not be advised to spend the time and effort required to become acclimated to cold. However, as more knowledge becomes available in this area, recommendations may change. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Neural mechanisms underlying paradoxical performance for monetary incentives are driven by loss aversion.

    Science.gov (United States)

    Chib, Vikram S; De Martino, Benedetto; Shimojo, Shinsuke; O'Doherty, John P

    2012-05-10

    Employers often make payment contingent on performance in order to motivate workers. We used fMRI with a novel incentivized skill task to examine the neural processes underlying behavioral responses to performance-based pay. We found that individuals' performance increased with increasing incentives; however, very high incentive levels led to the paradoxical consequence of worse performance. Between initial incentive presentation and task execution, striatal activity rapidly switched between activation and deactivation in response to increasing incentives. Critically, decrements in performance and striatal deactivations were directly predicted by an independent measure of behavioral loss aversion. These results suggest that incentives associated with successful task performance are initially encoded as a potential gain; however, when actually performing a task, individuals encode the potential loss that would arise from failure. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Effects of scopolamine and dextroamphetamine on human performance

    Science.gov (United States)

    Schmedtje, John F., Jr.; Oman, Charles M.; Letz, Richard; Baker, Edward L.

    1988-01-01

    The effects of two drugs used to prevent symptoms of motion sickness in the operational environment were examined in this study of human performance as measured by computer-based tests of cognitive and psychomotor skills. Each subject was exposed repetitively to five tests: symbol-digit substitution, simple reaction time, pattern recognition, digit span memory, and pattern memory. Although there have been previous reports of decreases in human performance in similar testing with higher dosages of scopolamine or dextroamphetamine, no significant decrements were observed with the operational-level combined dose used in this study (0.4 mg oral scopolamine and 5.0 mg oral dextroamphetamine.) The controversy over the use of combination drug therapy in this environnment is discussed along with the indications for further research based on the findings.

  20. Acute Effects of Two Different Resistance Circuit Training Protocols on Performance and Perceived Exertion in Semiprofessional Basketball Players.

    Science.gov (United States)

    Freitas, Tomás T; Calleja-González, Julio; Alarcón, Francisco; Alcaraz, Pedro E

    2016-02-01

    This study aimed to investigate the acute effects of two different resistance circuit training protocols on basketball players' physical and technical performance and rating of perceived exertion (RPE). In a repeated-measures, crossover experimental design, 9 semiprofessional basketball players performed a Power Circuit Training (PCT; 45% 1RM) and a High-Resistance Circuit Training (HRC; 6RM), on consecutive weeks. Vertical and horizontal jump performance, 3-points shooting accuracy, repeated-sprint ability (RSA), agility, and upper body power output were measured before and after training. The RPE was assessed 20 minutes after resistance training. One-way repeated-measures analysis of variance showed performance decrements in vertical jump height and peak power, horizontal jump distance, 3-points percentage, bench-press power output, RSA total and ideal time, and agility T-Test at total time following HRC, but not PCT (p ≤ 0.05). The RPE was higher in HRC compared with PCT. The results of this study indicated that HRC was perceived as being harder and produced higher fatigue levels, which in turn lowered acute performance. However, low-to-moderate intensity loads did not negatively affect performance. Thus, completing a PCT session may be the most appropriate option before a practice or game as it avoids acute-resistance-training-induced performance decrements. However, if the objective of the basketball session is to develop or perfect technical skills during fatiguing conditions, HRC may be the more suitable option.

  1. The antecedents of satisfaction with pay in teams: do performance-based compensation and autonomy keep team-members satisfied?

    Directory of Open Access Journals (Sweden)

    Ana-Maria Godeanu

    2012-06-01

    Full Text Available This paper aims to investigate the effects performance-based compensation and autonomy on satisfaction with pay in the context of team working. I develop a complex perspective that considers the influence of different monetary and non-monetary rewards on satisfaction with pay. Drawing from the agency theory, equity theory and theory of cooperation I predict that both piece rates and team-based rewards are associated with higher pay satisfaction. Moreover, I claim that both individual and team-based autonomy contribute to increased satisfaction with pay. Using a cross-sectional dataset of randomly selected European employees who are asked about specific working and living conditions, results confirm that both productivity-based rewards and autonomy are important for employee satisfaction. Managers should know when to introduce rewards based only on individual merits and when to give to use autonomy as a buffer to compensate for the potential lack of fairness in the payment system.

  2. Satiated with belongingness? Effects of acceptance, rejection, and task framing on self-regulatory performance.

    Science.gov (United States)

    DeWall, C Nathan; Baumeister, Roy F; Vohs, Kathleen D

    2008-12-01

    Seven experiments showed that the effects of social acceptance and social exclusion on self-regulatory performance depend on the prospect of future acceptance. Excluded participants showed decrements in self-regulation, but these decrements were eliminated if the self-regulation task was ostensibly a diagnostic indicator of the ability to get along with others. No such improvement was found when the task was presented as diagnostic of good health. Accepted participants, in contrast, performed relatively poorly when the task was framed as a diagnostic indicator of interpersonally attractive traits. Furthermore, poor performance among accepted participants was not due to self-handicapping or overconfidence. Offering accepted participants a cash incentive for self-regulating eliminated the self-regulation deficits. These findings provide evidence that the need to belong fits standard motivational patterns: Thwarting the drive intensifies it, whereas satiating it leads to temporary reduction in drive. Accepted people are normally good at self-regulation but are unwilling to exert the effort to self-regulate if self-regulation means gaining the social acceptance they have already obtained.

  3. Performing Performance Design Anglonationally

    DEFF Research Database (Denmark)

    2016-01-01

    Video recording of pecha kucha style bricolage aural enactment of an international version of performance design......Video recording of pecha kucha style bricolage aural enactment of an international version of performance design...

  4. Iron nutrition and premenopausal women: effects of poor iron status on physical and neuropsychological performance.

    Science.gov (United States)

    McClung, James P; Murray-Kolb, Laura E

    2013-01-01

    Iron is a nutritionally essential trace element that functions through incorporation into proteins and enzymes, many of which contribute to physical and neuropsychological performance. Poor iron status, including iron deficiency (ID; diminished iron stores) and iron deficiency anemia (IDA; poor iron stores and diminished hemoglobin), affects billions of people worldwide. This review focuses on physical and neuropsychological outcomes associated with ID and IDA in premenopausal women, as the prevalence of ID and IDA is often greater in premenopausal women than other population demographics. Recent studies addressing the physiological effects of poor iron status on physical performance, including work productivity, voluntary activity, and athletic performance, are addressed. Similarly, the effects of iron status on neurological performance, including cognition, affect, and behavior, are summarized. Nutritional countermeasures for the prevention of poor iron status and the restoration of decrements in performance outcomes are described.

  5. Unifying practice schedules in the timescales of motor learning and performance.

    Science.gov (United States)

    Verhoeven, F Martijn; Newell, Karl M

    2018-06-01

    In this article, we elaborate from a multiple time scales model of motor learning to examine the independent and integrated effects of massed and distributed practice schedules within- and between-sessions on the persistent (learning) and transient (warm-up, fatigue) processes of performance change. The timescales framework reveals the influence of practice distribution on four learning-related processes: the persistent processes of learning and forgetting, and the transient processes of warm-up decrement and fatigue. The superposition of the different processes of practice leads to a unified set of effects for massed and distributed practice within- and between-sessions in learning motor tasks. This analysis of the interaction between the duration of the interval of practice trials or sessions and parameters of the introduced time scale model captures the unified influence of the between trial and session scheduling of practice on learning and performance. It provides a starting point for new theoretically based hypotheses, and the scheduling of practice that minimizes the negative effects of warm-up decrement, fatigue and forgetting while exploiting the positive effects of learning and retention. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Identification of Resilient Individuals and Those at Risk for Performance Deficits under Stress

    Directory of Open Access Journals (Sweden)

    Brent eWinslow

    2015-09-01

    Full Text Available Human task performance is affected by exposure to physiological and psychological stress. The ability to measure the physiological response to stressors and correlate that to task performance could be used to identify resilient individuals or those at risk for stress-related performance decrements. Accomplishing this prior to performance under severe stress or the development of clinical stress disorders could facilitate focused preparation such as tailoring training to individual needs. Here we measure the effects of stress on physiological response and performance through behavior, physiological sensors, and subjective ratings, and identify which individuals are at risk for stress-related performance decrements. Participants performed military-relevant training tasks under stress in a virtual environment, with autonomic and hypothalamic-pituitary-adrenal axis (HPA reactivity analyzed. Self-reported stress, as well as physiological indices of stress, increased in the group pre-exposed to socioevaluative stress. Stress response was effectively captured via electrodermal and cardiovascular measures of heart rate and skin conductance level. A resilience classification algorithm was developed based upon physiological reactivity, which correlated with baseline unstressed physiological and self-reported stress values. Outliers were identified in the experimental group that had a significant mismatch between self-reported stress and salivary cortisol. Baseline stress measurements were predictive of individual resilience to stress, including the impact stress had on physiological reactivity and performance. Such an approach may have utility in identifying individuals at risk for problems performing under severe stress. Continuing work has focused on adapting this method for military personnel, and assessing the utility of various coping and decision-making strategies on performance and physiological stress.

  7. Identification of resilient individuals and those at risk for performance deficits under stress.

    Science.gov (United States)

    Winslow, Brent D; Carroll, Meredith B; Martin, Jonathan W; Surpris, Glenn; Chadderdon, George L

    2015-01-01

    Human task performance is affected by exposure to physiological and psychological stress. The ability to measure the physiological response to stressors and correlate that to task performance could be used to identify resilient individuals or those at risk for stress-related performance decrements. Accomplishing this prior to performance under severe stress or the development of clinical stress disorders could facilitate focused preparation such as tailoring training to individual needs. Here we measure the effects of stress on physiological response and performance through behavior, physiological sensors, and subjective ratings, and identify which individuals are at risk for stress-related performance decrements. Participants performed military-relevant training tasks under stress in a virtual environment, with autonomic and hypothalamic-pituitary-adrenal axis (HPA) reactivity analyzed. Self-reported stress, as well as physiological indices of stress, increased in the group pre-exposed to socioevaluative stress. Stress response was effectively captured via electrodermal and cardiovascular measures of heart rate and skin conductance level. A resilience classification algorithm was developed based upon physiological reactivity, which correlated with baseline unstressed physiological and self-reported stress values. Outliers were identified in the experimental group that had a significant mismatch between self-reported stress and salivary cortisol. Baseline stress measurements were predictive of individual resilience to stress, including the impact stress had on physiological reactivity and performance. Such an approach may have utility in identifying individuals at risk for problems performing under severe stress. Continuing work has focused on adapting this method for military personnel, and assessing the utility of various coping and decision-making strategies on performance and physiological stress.

  8. Human manual control performance in hyper-gravity.

    Science.gov (United States)

    Clark, Torin K; Newman, Michael C; Merfeld, Daniel M; Oman, Charles M; Young, Laurence R

    2015-05-01

    Hyper-gravity provides a unique environment to study how misperceptions impact control of orientation relative to gravity. Previous studies have found that static and dynamic roll tilts are perceptually overestimated in hyper-gravity. The current investigation quantifies how this influences control of orientation. We utilized a long-radius centrifuge to study manual control performance in hyper-gravity. In the dark, subjects were tasked with nulling out a pseudo-random roll disturbance on the cab of the centrifuge using a rotational hand controller to command their roll rate in order to remain perceptually upright. The task was performed in 1, 1.5, and 2 G's of net gravito-inertial acceleration. Initial performance, in terms of root-mean-square deviation from upright, degraded in hyper-gravity relative to 1 G performance levels. In 1.5 G, initial performance degraded by 26 % and in 2 G, by 45 %. With practice, however, performance in hyper-gravity improved to near the 1 G performance level over several minutes. Finally, pre-exposure to one hyper-gravity level reduced initial performance decrements in a different, novel, hyper-gravity level. Perceptual overestimation of roll tilts in hyper-gravity leads to manual control performance errors, which are reduced both with practice and with pre-exposure to alternate hyper-gravity stimuli.

  9. Representation of the Physiological Factors Contributing to Postflight Changes in Functional Performance Using Motion Analysis Software

    Science.gov (United States)

    Parks, Kelsey

    2010-01-01

    Astronauts experience changes in multiple physiological systems due to exposure to the microgravity conditions of space flight. To understand how changes in physiological function influence functional performance, a testing procedure has been developed that evaluates both astronaut postflight functional performance and related physiological changes. Astronauts complete seven functional and physiological tests. The objective of this project is to use motion tracking and digitizing software to visually display the postflight decrement in the functional performance of the astronauts. The motion analysis software will be used to digitize astronaut data videos into stick figure videos to represent the astronauts as they perform the Functional Tasks Tests. This project will benefit NASA by allowing NASA scientists to present data of their neurological studies without revealing the identities of the astronauts.

  10. The Impact of Interpersonal Discrimination and Stress on Health and Performance for Early Career STEM Academicians

    Science.gov (United States)

    O’Brien, Katharine R.; McAbee, Samuel T.; Hebl, Michelle R.; Rodgers, John R.

    2016-01-01

    The present study examines the consequences of perceived interpersonal discrimination on stress, health, and performance in a sample of 210 science, technology, engineering, and mathematics (STEM) academicians. Using a path model, we test the relation that perceived interpersonal discrimination has on stress and the relation of stress to physical health maladies and on current and future performance. In so doing, we assess the link between discrimination and decrements in performance over time. Additionally, we test supervisor social support as a moderator of the discrimination–stress relation. Findings support relations between perceived interpersonal discrimination and stress, which in turn relates to declines in physical health and performance outcomes. Moreover, supervisory support is shown to mitigate the influence of interpersonal discrimination on stress in STEM academicians. PMID:27199848

  11. Summary of Research Issues in Behavior and Performance in Isolated and Confined Extreme (ICE) Environments

    Science.gov (United States)

    Palinkas, Lawrence A.

    2000-01-01

    The papers presented in this section describe changes in behavior and performance in various isolated and confined extreme (ICE) environments, including Antarctic expeditions and research stations, space simulators and isolation chambers, and submarines. Each of these environments possesses characteristics that are in some way analogous to those found on long-duration space missions. Despite differences in length of mission, characteristics of mission personnel or crew, and characteristics in the physical environment, the various ICE environments described in this collection of papers appear to produce similar changes in behavior and performance. These changes include increased disturbances of mood, increased rates of psychiatric disorder, increased interpersonal tension, and a disruption of circadian rhythms. However, these environments do not inherently produce decrements in performance. Palinkas and colleagues suggest that prolonged exposure to the isolation and confinement in the Antarctic can actually have positive or "salutogenic" effects as well, evidenced by a decrease in mood disturbances and increase in performance measures.

  12. The impact of interpersonal discrimination and stress on health and performance for early career STEM academicians

    Directory of Open Access Journals (Sweden)

    Katharine Ridgway O'Brien

    2016-04-01

    Full Text Available The present study examines the consequences of perceived interpersonal discrimination on stress, health, and performance in a sample of 210 STEM academicians. Using a path model, we test the relation that perceived interpersonal discrimination has on stress and the relation of stress to physical health maladies and on current and future performance. In so doing, we assess the link between discrimination and decrements in performance over time. Additionally, we test supervisor social support as a moderator of the discrimination–stress relation. Findings support relations between perceived interpersonal discrimination and stress, which in turn relates to declines in physical health and performance outcomes. Moreover, supervisory support is shown to mitigate the influence of interpersonal discrimination on stress in STEM academicians.

  13. High-performance sport, marijuana, and cannabimimetics.

    Science.gov (United States)

    Hilderbrand, Richard L

    2011-11-01

    The prohibition on use of cannabinoids in sporting competitions has been widely debated and continues to be a contentious issue. Information continues to accumulate on the adverse health effects of smoked marijuana and the decrement of performance caused by the use of cannabinoids. The objective of this article is to provide an overview of cannabinoids and cannabimimetics that directly or indirectly impact sport, the rules of sport, and performance of the athlete. This article reviews some of the history of marijuana in Olympic and Collegiate sport, summarizes the guidelines by which a substance is added to the World Anti-Doping Agency Prohibited List, and updates information on the pharmacologic effects of cannabinoids and their mechanism of action. The recently marketed cannabimimetics Spice and K2 are included in the discussion as they activate the same receptors as are activated by THC. The article also provides a view as to why the World Anti-Doping Agency prohibits cannabinoid or cannabimimetic use incompetition and should continue to do so.

  14. The effects of Ramadan intermittent fasting on athletic performance: recommendations for the maintenance of physical fitness.

    Science.gov (United States)

    Chaouachi, Anis; Leiper, John B; Chtourou, Hamdi; Aziz, Abdul Rashid; Chamari, Karim

    2012-01-01

    The behavioural modifications that accompany Ramadan intermittent fasting (RIF) are usually associated with some alterations in the metabolic, physiological, and psychological responses of athletes that may affect sport performance. Muslim athletes who are required to train and/or compete during the month-long, diurnal fast must adopt coping strategies that allow them to maintain physical fitness and motivation if they are to perform at the highest level. This updated review aims to present the current state of knowledge of the effects of RIF on training and performance, focusing on key-factors that contribute to the effects of Ramadan on exercise performance: energy restriction, sleep deprivation, circadian rhythm perturbation, dehydration, and alterations in the training load. The available literature contain few studies that have examined the effects of RIF on physical performance in athletes and, to date, the results are inconclusive, so the effects of RIF on competition outcomes are not at present wholly understood. The diverse findings probably indicate individual differences in the adaptability and self-generated coping strategies of athletes during fasting and training. However, the results of the small number of well-controlled studies that have examined the effects of Ramadan on athletic performance suggest that few aspects of physical fitness are negatively affected, and where decrements are observed these are usually modest. Subjective feelings of fatigue and other mood indicators are often cited as implying additional stress on the athlete throughout Ramadan, but most studies show that these factors may not result in decreases in performance and that perceived exercise intensity is unlikely to increase to any significant degree. Current evidence from good, well-controlled research supports the conclusion that athletes who maintain their total energy and macronutrient intake, training load, body composition, and sleep length and quality are unlikely to

  15. Does ovulation affect performance in tennis players?

    Science.gov (United States)

    Otaka, Machiko; Chen, Shu-Man; Zhu, Yong; Tsai, Yung-Shen; Tseng, Ching-Yu; Fogt, Donovan L; Lim, Boon-Hooi; Huang, Chih-Yang; Kuo, Chia-Hua

    2018-01-01

    Scientific data on the performance of collegiate female tennis players during the menstrual phases are scarce. Double-blind, counter-balanced, crossover trials were conducted to examine whether tennis performance was affected during menstruation, with and without dehydroepiandrosterone sulfate (DHEA-S) supplementation. Ten Division 1 collegiate tennis players (aged 18-22 years) were evenly assigned into placebo-supplemented and DHEA-supplemented (25 mg/day) trials. Treatments were exchanged among the participants after a 28-day washout. Tennis serve performance was assessed on the first day of menstrual bleeding (day 0/28) and on days 7, 14 and 21. Mood state was unaltered during the menstrual cycles in both trials. The lowest tennis serve performance score (speed times accuracy) occurred on day 14 (P=0.06 vs day 0; P=0.01 vs day 21) in both placebo and DHEA trials. Decreased performance on day 14 was explained by decreased accuracy (P=0.03 vs day 0/28; P=0.01 vs day 21), but not velocity itself. Isometric hip strength, but not quadriceps strength, was moderately lower on day 14 (P=0.08). Increasing plasma DHEA-S (by ~65%) during the DHEA-supplemented trial had no effects on mood state, sleep quality or tennis serve performance. We have shown that menses does not affect serve performance of collegiate tennis players. However, the observed decrement in the accuracy of serve speed near ovulation warrants further investigation.

  16. The effects of fatigue on performance in simulated nursing work.

    Science.gov (United States)

    Barker, Linsey M; Nussbaum, Maury A

    2011-09-01

    Fatigue is associated with increased rates of medical errors and healthcare worker injuries, yet existing research in this sector has not considered multiple dimensions of fatigue simultaneously. This study evaluated hypothesised causal relationships between mental and physical fatigue and performance. High and low levels of mental and physical fatigue were induced in 16 participants during simulated nursing work tasks in a laboratory setting. Task-induced changes in fatigue dimensions were quantified using both subjective and objective measures, as were changes in performance on physical and mental tasks. Completing the simulated work tasks increased total fatigue, mental fatigue and physical fatigue in all experimental conditions. Higher physical fatigue adversely affected measures of physical and mental performance, whereas higher mental fatigue had a positive effect on one measure of mental performance. Overall, these results suggest causal effects between manipulated levels of mental and physical fatigue and task-induced changes in mental and physical performance. STATEMENT OF RELEVANCE: Nurse fatigue and performance has implications for patient and provider safety. Results from this study demonstrate the importance of a multidimensional view of fatigue in understanding the causal relationships between fatigue and performance. The findings can guide future work aimed at predicting fatigue-related performance decrements and designing interventions.

  17. Physiological Factors Contributing to Postflight Changes in Functional Performance

    Science.gov (United States)

    Bloomberg, J. J.; Feedback, D. L.; Feiverson, A. H.; Lee, S. M. C.; Mulavara, A. P.; Peters, B. T.; Platts, S. H.; Reschke, M. F.; Ryder, J.; Spiering, B. A.; hide

    2009-01-01

    Astronauts experience alterations in multiple physiological systems due to exposure to the microgravity conditions of space flight. These physiological changes include sensorimotor disturbances, cardiovascular deconditioning and loss of muscle mass and strength. These changes might affect the ability of crewmembers to perform critical mission tasks immediately after landing on lunar and Martian surfaces. To date, changes in functional performance have not been systematically studied or correlated with physiological changes. To understand how changes in physiological function impact functional performance an interdisciplinary pre/postflight testing regimen (Functional Task Test, FTT) has been developed that systematically evaluates both astronaut postflight functional performance and related physiological changes. The overall objectives of the FTT are to: Develop a set of functional tasks that represent critical mission tasks for Constellation. Determine the ability to perform these tasks after flight. Identify the key physiological factors that contribute to functional decrements. Use this information to develop targeted countermeasures. The functional test battery was designed to address high priority tasks identified by the Constellation program as critical for mission success. The set of functional tests making up the FTT include the: 1) Seat Egress and Walk Test, 2) Ladder Climb Test, 3) Recovery from Fall/Stand Test, 4) Rock Translation Test, 5) Jump Down Test, 6) Torque Generation Test, and 7) Construction Activity Board Test. Corresponding physiological measures include assessments of postural and gait control, dynamic visual acuity, fine motor control, plasma volume, orthostatic intolerance, upper and lower body muscle strength, power, fatigue, control and neuromuscular drive. Crewmembers will perform both functional and physiological tests before and after short (Shuttle) and long-duration (ISS) space flight. Data will be collected on R+0 (Shuttle only), R

  18. Smoked marijuana attenuates performance and mood disruptions during simulated night shift work.

    Science.gov (United States)

    Keith, Diana R; Gunderson, Erik W; Haney, Margaret; Foltin, Richard W; Hart, Carl L

    2017-09-01

    Individuals who work nonstandard schedules, such as rotating or night shifts, are more susceptible to workplace injuries, performance decrements, and reduced productivity. This population is also almost twice as likely to use illicit drugs as individuals working a standard day shift. The purpose of this study was to examine the effects of smoked marijuana on performance, mood, and sleep during simulated shift work. Ten experienced marijuana smokers completed this 23-day, within-participant residential study. They smoked a single marijuana cigarette (0, 1.9, 3.56% Δ 9 -THC) one hour after waking for three consecutive days under two shift conditions: day shift and night shift. Shifts alternated three times during the study, and shift conditions were separated by an 'off' day. When participants smoked placebo cigarettes, psychomotor performance and subjective-effect ratings were altered during the night shift compared to the day shift: performance (e.g., vigilance) and a few subjective ratings were decreased (e.g., "Self-Confident"), whereas other ratings were increased (e.g., "Tired"). Objective and subjective measures of sleep were also disrupted, but to a lesser extent. Marijuana attenuated some performance, mood, and sleep disruptions: participants performed better on vigilance tasks, reported being less miserable and tired and sleep a greater number of minutes. Limited negative effects of marijuana were noted. These data demonstrate that abrupt shift changes produce performance, mood, and sleep decrements during night shift work and that smoked marijuana containing low to moderate Δ 9 -THC concentrations can offset some of these effects in frequent marijuana smokers. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Reward-based hypertension control by a synthetic brain-dopamine interface.

    Science.gov (United States)

    Rössger, Katrin; Charpin-El Hamri, Ghislaine; Fussenegger, Martin

    2013-11-05

    Synthetic biology has significantly advanced the design of synthetic trigger-controlled devices that can reprogram mammalian cells to interface with complex metabolic activities. In the brain, the neurotransmitter dopamine coordinates communication with target neurons via a set of dopamine receptors that control behavior associated with reward-driven learning. This dopamine transmission has recently been suggested to increase central sympathetic outflow, resulting in plasma dopamine levels that correlate with corresponding brain activities. By functionally rewiring the human dopamine receptor D1 (DRD1) via the second messenger cyclic adenosine monophosphate (cAMP) to synthetic promoters containing cAMP response element-binding protein 1(CREB1)-specific cAMP-responsive operator modules, we have designed a synthetic dopamine-sensitive transcription controller that reversibly fine-tunes specific target gene expression at physiologically relevant brain-derived plasma dopamine levels. Following implantation of circuit-transgenic human cell lines insulated by semipermeable immunoprotective microcontainers into mice, the designer device interfaced with dopamine-specific brain activities and produced a systemic expression response when the animal's reward system was stimulated by food, sexual arousal, or addictive drugs. Reward-triggered brain activities were able to remotely program peripheral therapeutic implants to produce sufficient amounts of the atrial natriuretic peptide, which reduced the blood pressure of hypertensive mice to the normal physiologic range. Seamless control of therapeutic transgenes by subconscious behavior may provide opportunities for treatment strategies of the future.

  20. A Reward-Based Behavioral Platform to Measure Neural Activity during Head-Fixed Behavior

    Directory of Open Access Journals (Sweden)

    Andrew H. Micallef

    2017-05-01

    Full Text Available Understanding the neural computations that contribute to behavior requires recording from neurons while an animal is behaving. This is not an easy task as most subcellular recording techniques require absolute head stability. The Go/No-Go sensory task is a powerful decision-driven task that enables an animal to report a binary decision during head-fixation. Here we discuss how to set up an Ardunio and Python based platform system to control a Go/No-Go sensory behavior paradigm. Using an Arduino micro-controller and Python-based custom written program, a reward can be delivered to the animal depending on the decision reported. We discuss the various components required to build the behavioral apparatus that can control and report such a sensory stimulus paradigm. This system enables the end user to control the behavioral testing in real-time and therefore it provides a strong custom-made platform for probing the neural basis of behavior.

  1. Feasibility and impact study of a reward-based mobile application to improve adolescents' snacking habits.

    Science.gov (United States)

    De Cock, Nathalie; Van Lippevelde, Wendy; Vangeel, Jolien; Notebaert, Melissa; Beullens, Kathleen; Eggermont, Steven; Deforche, Benedicte; Maes, Lea; Goossens, Lien; Verbeken, Sandra; Moens, Ellen; Vervoort, Leentje; Braet, Caroline; Huybregts, Lieven; Kolsteren, Patrick; Van Camp, John; Lachat, Carl

    2018-04-02

    Adolescents' snacking habits are driven by both explicit reflective and implicit hedonic processes. Hedonic pathways and differences in sensitivity to food rewards in addition to reflective determinants should be considered. The present study evaluated the feasibility and impact of a mobile phone-delivered intervention, incorporating explicit reflective and implicit rewarding strategies, on adolescents' snack intake. Adolescents (n 988; mean age 14·9 (sd 0·70) years, 59·4 % boys) completed a non-randomized clustered controlled trial. Adolescents (n 416) in the intervention schools (n 3) were provided with the intervention application for four weeks, while adolescents (n 572) in the control schools (n 3) followed the regular curriculum. Outcomes were differences in healthy snacking ratio and key determinants (awareness, intention, attitude, self-efficacy, habits and knowledge). Process evaluation data were collected via questionnaires and through log data of the app. No significant positive intervention effects on the healthy snack ratio (b=-3·52 (se 1·82), P>0·05) or targeted determinants were observed. Only 268 adolescents started using the app, of whom only fifty-five (20·5 %) still logged in after four weeks. Within the group of users, higher exposure to the app was not significantly associated with positive intervention effects. App satisfaction ratings were low in both high and low user groups. Moderation analyses revealed small positive intervention effects on the healthy snack ratio in high compared with low reward-sensitive boys (b=1·38 (se 0·59), P<0·05). The intervention was not able to improve adolescents' snack choices, due to low reach and exposure. Future interventions should consider multicomponent interventions, teacher engagement, exhaustive participatory app content development and tailoring.

  2. Dose Dependent Dopaminergic Modulation of Reward-Based Learning in Parkinson's Disease

    Science.gov (United States)

    van Wouwe, N. C.; Ridderinkhof, K. R.; Band, G. P. H.; van den Wildenberg, W. P. M.; Wylie, S. A.

    2012-01-01

    Learning to select optimal behavior in new and uncertain situations is a crucial aspect of living and requires the ability to quickly associate stimuli with actions that lead to rewarding outcomes. Mathematical models of reinforcement-based learning to select rewarding actions distinguish between (1) the formation of stimulus-action-reward…

  3. Effect of the insulation materials filling on the thermal performance of sintered hollow bricks under the air-conditioning intermittent operation

    Directory of Open Access Journals (Sweden)

    Chaoping Hou

    2018-06-01

    Full Text Available Wall insulation performance is an important factor affecting building energy consumption and indoor comfortable level. This study proposes that the insulation materials are filled into the cavities of the sintered hollow brick to replace the single insulation layer. The physical models of typical walls were built by the hollow bricks filled with expanding polystyrene board (EPS in cavities and wall thermal performance is numerically analyzed by the Finite Volume Method under air-conditioning intermittent operation, which conforms to the actual operation rules of air-conditioning. Results show that filling EPS in cavities is beneficial to improve the thermal performance of the bricks, and the larger the EPS filling ratio, the higher the thermal performance improvement. The EPS filling ratio increase has the higher sensitivity on inner surface heat flow under the low EPS filling ratio, and filling EPS in the external cavities is optimum with the decrement rate 5.92% higher than filling EPS in internal cavities for the EPS filling ratio of 20%, while filling EPS in internal and external cavities simultaneously is optimum with decrement rate 2.45%–6.87% higher than that with filling EPS in the internal cavities for the EPS filling ratio of 40%–80%. Keywords: Insulation filling ratio, Insulation filling location, Thermal performance, Sintered hollow bricks

  4. Evaluating Suit Fit Using Performance Degradation

    Science.gov (United States)

    Margerum, Sarah E.; Cowley, Matthew; Harvill, Lauren; Benson, Elizabeth; Rajulu, Sudhakar

    2011-01-01

    The Mark III suit has multiple sizes of suit components (arm, leg, and gloves) as well as sizing inserts to tailor the fit of the suit to an individual. This study sought to determine a way to identify the point an ideal suit fit transforms into a bad fit and how to quantify this breakdown using mobility-based physical performance data. This study examined the changes in human physical performance via degradation of the elbow and wrist range of motion of the planetary suit prototype (Mark III) with respect to changes in sizing and as well as how to apply that knowledge to suit sizing options and improvements in suit fit. The methods implemented in this study focused on changes in elbow and wrist mobility due to incremental suit sizing modifications. This incremental sizing was within a range that included both optimum and poor fit. Suited range of motion data was collected using a motion analysis system for nine isolated and functional tasks encompassing the elbow and wrist joints. A total of four subjects were tested with motions involving both arms simultaneously as well as the right arm only. The results were then compared across sizing configurations. The results of this study indicate that range of motion may be used as a viable parameter to quantify at what stage suit sizing causes a detriment in performance; however the human performance decrement appeared to be based on the interaction of multiple joints along a limb, not a single joint angle. The study was able to identify a preliminary method to quantify the impact of size on performance and to develop a means to gauge tolerances around optimal size. More work is needed to improve the assessment of optimal fit and to compensate for multiple joint interactions.

  5. Sleep Disordered Breathing and Academic Performance: A Meta-analysis.

    Science.gov (United States)

    Galland, Barbara; Spruyt, Karen; Dawes, Patrick; McDowall, Philippa S; Elder, Dawn; Schaughency, Elizabeth

    2015-10-01

    Sleep-disordered breathing (SDB) in children is associated with daytime functioning decrements in cognitive performance and behavioral regulation. Studies addressing academic achievement are underrepresented. This study aimed to evaluate the strength of the relationships between SDB and achievement in core domains and general school performance. Data sources included PubMed, Web of Science, CINAHL, and PsycINFO. Studies of school-aged children investigating the relationships between SDB and academic achievement were selected for inclusion in a systematic literature review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data extracted were converted into standardized mean differences; effect sizes (ES) and statistics were calculated by using random-effects models. Heterogeneity tests (I(2)) were conducted. Of 488 studies, 16 met eligibility criteria. SDB was significantly associated with poorer academic performance for core academic domains related to language arts (ES -0.31; P performance. Variable definitions of both academic performance and SDB likely contributed to the heterogeneity among published investigations. Clear links between SDB and poorer academic performance in school-age children are demonstrated. ES statistics were in the small to medium range, but nevertheless the findings serve to highlight to parents, teachers, and clinicians that SDB in children may contribute to academic difficulties some children face. Copyright © 2015 by the American Academy of Pediatrics.

  6. Effects of caloric restriction and overnight fasting on cycling endurance performance.

    Science.gov (United States)

    Ferguson, Lisa M; Rossi, Kelly A; Ward, Emily; Jadwin, Emily; Miller, Todd A; Miller, Wayne C

    2009-03-01

    In addition to aerobic endurance and anaerobic capacity, high power-to-weight ratio (PWR) is important for cycling performance. Cyclists often try to lose weight before race season to improve body composition and optimize PWR. Research has demonstrated body fat-reducing benefits of exercise after fasting overnight. We hypothesized that fasted-state exercise in calorie-restricted trained cyclists would not result in performance decrements and that their PWR would improve significantly. We also hypothesized that substrate use during fasted-state submaximal endurance cycling would shift to greater reliance on fat. Ten trained, competitive cyclists completed a protocol consisting of baseline testing, 3 weeks of caloric restriction (CR), and post-CR testing. The testing sessions measured pre- and post-CR values for resting metabolic rate (RMR), body composition, VO2, PWR and power-to-lean weight ratio (PLWR), and power output, as well as 2-hour submaximal cycling performance, rating of perceived exertion (RPE), and respiratory exchange ratio (RER). There were no significant differences between baseline and post-CR for submaximal trial RER, power output, VO2, RMR, VO2max, or workload at VO2max. However, RPE was significantly lower, and PWR was significantly higher post-CR, whereas RER did not change. The cyclists' PWR and body composition improved significantly, and their overall weight, fat weight, and body fat percentage decreased. Lean mass was maintained. The cyclists' RPE decreased significantly during 2 hours of submaximal cycling post-CR, and there was no decrement in submaximal or maximal cycling performance after 3 weeks of CR combined with overnight fasting. Caloric restriction (up to 40% for 3 weeks) and exercising after fasting overnight can improve a cyclist's PWR without compromising endurance cycling performance.

  7. Cold-Blooded Attention: Finger Temperature Predicts Attentional Performance.

    Science.gov (United States)

    Vergara, Rodrigo C; Moënne-Loccoz, Cristóbal; Maldonado, Pedro E

    2017-01-01

    Thermal stress has been shown to increase the chances of unsafe behavior during industrial and driving performances due to reductions in mental and attentional resources. Nonetheless, establishing appropriate safety standards regarding environmental temperature has been a major problem, as modulations are also be affected by the task type, complexity, workload, duration, and previous experience with the task. To bypass this attentional and thermoregulatory problem, we focused on the body rather than environmental temperature. Specifically, we measured tympanic, forehead, finger and environmental temperatures accompanied by a battery of attentional tasks. We considered a 10 min baseline period wherein subjects were instructed to sit and relax, followed by three attentional tasks: a continuous performance task (CPT), a flanker task (FT) and a counting task (CT). Using multiple linear regression models, we evaluated which variable(s) were the best predictors of performance. The results showed a decrement in finger temperature due to instruction and task engagement that was absent when the subject was instructed to relax. No changes were observed in tympanic or forehead temperatures, while the environmental temperature remained almost constant for each subject. Specifically, the magnitude of the change in finger temperature was the best predictor of performance in all three attentional tasks. The results presented here suggest that finger temperature can be used as a predictor of alertness, as it predicted performance in attentional tasks better than environmental temperature. These findings strongly support that peripheral temperature can be used as a tool to prevent unsafe behaviors and accidents.

  8. Cold-Blooded Attention: Finger Temperature Predicts Attentional Performance

    Directory of Open Access Journals (Sweden)

    Rodrigo C. Vergara

    2017-09-01

    Full Text Available Thermal stress has been shown to increase the chances of unsafe behavior during industrial and driving performances due to reductions in mental and attentional resources. Nonetheless, establishing appropriate safety standards regarding environmental temperature has been a major problem, as modulations are also be affected by the task type, complexity, workload, duration, and previous experience with the task. To bypass this attentional and thermoregulatory problem, we focused on the body rather than environmental temperature. Specifically, we measured tympanic, forehead, finger and environmental temperatures accompanied by a battery of attentional tasks. We considered a 10 min baseline period wherein subjects were instructed to sit and relax, followed by three attentional tasks: a continuous performance task (CPT, a flanker task (FT and a counting task (CT. Using multiple linear regression models, we evaluated which variable(s were the best predictors of performance. The results showed a decrement in finger temperature due to instruction and task engagement that was absent when the subject was instructed to relax. No changes were observed in tympanic or forehead temperatures, while the environmental temperature remained almost constant for each subject. Specifically, the magnitude of the change in finger temperature was the best predictor of performance in all three attentional tasks. The results presented here suggest that finger temperature can be used as a predictor of alertness, as it predicted performance in attentional tasks better than environmental temperature. These findings strongly support that peripheral temperature can be used as a tool to prevent unsafe behaviors and accidents.

  9. The Influence of Hand Immersion Duration on Manual Performance.

    Science.gov (United States)

    Ray, Matthew; Sanli, Elizabeth; Brown, Robert; Ennis, Kerri Ann; Carnahan, Heather

    2017-08-01

    To investigate the effect of hand immersion duration on manipulative ability and tactile sensitivity. Individuals in maritime settings often work with hands that have been immersed in water. Although research has shown that hand immersion duration differentially impacts skin adhesion and tactile sensitivity, the effect of hand immersion on manipulative ability has not been directly tested. Given how critical manipulative ability is for the safety and performance of those working at sea, the effect of hand immersion duration on manual performance was investigated. Tests of manipulative ability (Purdue Pegboard, Grooved Pegboard, reef knot untying) and tactile sensitivity (Touch-Test) were completed following no-exposure, short-exposure, and long-exposure hand immersions in thermoneutral water. Compared to the no immersion condition, the Purdue Pegboard performance was reduced in both immersion conditions (short exposure, -11%; long exposure, -8%). A performance decrement was only observed in the short exposure condition (+15% in time to complete task) for the reef knot untying task. There were no statistical differences in the Grooved Pegboard or Touch-Test scores between exposure conditions. Immersing the hands in water decreases manipulative ability except for when object properties reduce the slipperiness between the hand and object. Manual performance in a wet environment may be conserved by designing tools and objects with edges and textures that can offset the slipperiness of wet hands. To maintain safety, the time requirements for working with wet hands needs to be considered.

  10. The 5-choice continuous performance test: evidence for a translational test of vigilance for mice.

    Directory of Open Access Journals (Sweden)

    Jared W Young

    Full Text Available 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.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.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.

  11. The reliability and validity of a soccer-specific nonmotorised treadmill simulation (intermittent soccer performance test).

    Science.gov (United States)

    Aldous, Jeffrey W F; Akubat, Ibrahim; Chrismas, Bryna C R; Watkins, Samuel L; Mauger, Alexis R; Midgley, Adrian W; Abt, Grant; Taylor, Lee

    2014-07-01

    This study investigated the reliability and validity of a novel nonmotorised treadmill (NMT)-based soccer simulation using a novel activity category called a "variable run" to quantify fatigue during high-speed running. Twelve male University soccer players completed 3 familiarization sessions and 1 peak speed assessment before completing the intermittent soccer performance test (iSPT) twice. The 2 iSPTs were separated by 6-10 days. The total distance, sprint distance, and high-speed running distance (HSD) were 8,968 ± 430 m, 980 ± 75 m and 2,122 ± 140 m, respectively. No significant difference (p > 0.05) was found between repeated trials of the iSPT for all physiological and performance variables. Reliability measures between iSPT1 and iSPT2 showed good agreement (coefficient of variation: 0.80). Furthermore, the variable run phase showed HSD significantly decreased (p ≤ 0.05) in the last 15 minutes (89 ± 6 m) compared with the first 15 minutes (85 ± 7 m), quantifying decrements in high-speed exercise compared with the previous literature. This study validates the iSPT as a NMT-based soccer simulation compared with the previous match-play data and is a reliable tool for assessing and monitoring physiological and performance variables in soccer players. The iSPT could be used in a number of ways including player rehabilitation, understanding the efficacy of nutritional interventions, and also the quantification of environmentally mediated decrements on soccer-specific performance.

  12. Short-term memory and dual task performance

    Science.gov (United States)

    Regan, J. E.

    1982-01-01

    Two hypotheses concerning the way in which short-term memory interacts with another task in a dual task situation are considered. It is noted that when two tasks are combined, the activity of controlling and organizing performance on both tasks simultaneously may compete with either task for a resource; this resource may be space in a central mechanism or general processing capacity or it may be some task-specific resource. If a special relationship exists between short-term memory and control, especially if there is an identity relationship between short-term and a central controlling mechanism, then short-term memory performance should show a decrement in a dual task situation. Even if short-term memory does not have any particular identity with a controlling mechanism, but both tasks draw on some common resource or resources, then a tradeoff between the two tasks in allocating resources is possible and could be reflected in performance. The persistent concurrence cost in memory performance in these experiments suggests that short-term memory may have a unique status in the information processing system.

  13. Effects on Task Performance and Psychophysiological Measures of Performance During Normobaric Hypoxia Exposure

    Science.gov (United States)

    Stephens, Chad; Kennedy, Kellie; Napoli, Nicholas; Demas, Matthew; Barnes, Laura; Crook, Brenda; Williams, Ralph; Last, Mary Carolyn; Schutte, Paul

    2017-01-01

    Human-autonomous systems have the potential to mitigate pilot cognitive impairment and improve aviation safety. A research team at NASA Langley conducted an experiment to study the impact of mild normobaric hypoxia induction on aircraft pilot performance and psychophysiological state. A within-subjects design involved non-hypoxic and hypoxic exposures while performing three 10-minute tasks. Results indicated the effect of 15,000 feet simulated altitude did not induce significant performance decrement but did produce increase in perceived workload. Analyses of psychophysiological responses evince the potential of biomarkers for hypoxia onset. This study represents on-going work at NASA intending to add to the current knowledge of psychophysiologically-based input to automation to increase aviation safety. Analyses involving coupling across physiological systems and wavelet transforms of cortical activity revealed patterns that can discern between the simulated altitude conditions. Specifically, multivariate entropy of ECG/Respiration components were found to be significant predictors (pTask performance was not appreciably impacted by the effect of 15,000 feet simulated altitude. Analyses of psychophysiological responses evince the potential of biomarkers for mild hypoxia onset.The potential for identifying shifts in underlying cortical and physiological systems could serve as a means to identify the onset of deteriorated cognitive state. Enabling such assessment in future flightdecks could permit increasingly autonomous systems-supported operations. Augmenting human operator through assessment of cognitive impairment has the potential to further improve operator performance and mitigate human error in safety critical contexts. This study represents ongoing work at NASA intending to add to the current knowledge of psychophysiologically-based input to automation to increase aviation safety.

  14. Impact of time on task on ADHD patient's performances in a virtual classroom.

    Science.gov (United States)

    Bioulac, Stéphanie; Lallemand, Stéphanie; Rizzo, Albert; Philip, Pierre; Fabrigoule, Colette; Bouvard, Manuel Pierre

    2012-09-01

    Use of virtual reality tool is interesting for the evaluation of Attention Deficit/Hyperactivity Disorder (ADHD) patients. The virtual environment offers the opportunity to administer controlled task like the typical neuropsychological tools, but in an environment much more like standard classroom. Previous studies showed that a virtual classroom was able to distinguish performances of children with and without ADHD, but the evolution of performances over time has not been explored. The aim of this work was to study time on task effects on performances of ADHD children compared to controls in a virtual classroom (VC). 36 boys aged from 7 to 10 years completed the virtual classroom task. We compared the performance of the children diagnosed with ADHD with those of the control children. We also compared attentional performances recorded in the virtual classroom with measures of the Continuous Performance Test (CPT II). Our results showed that patients differ from control subjects in term of time effect on performances. If controls sustained performances over time in the virtual reality task, ADHD patients showed a significant performance decrement over time. Performances at the VC correlated with CPT II measures. ADHD children are vulnerable to a time on task effect on performances which could explain part of their difficulties. Virtual reality is a reliable method to test ADHD children ability to sustain performances over time. Copyright © 2012 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  15. The movement kinematics and learning strategies associated with adopting different foci of attention during both acquisition and anxious performance.

    Directory of Open Access Journals (Sweden)

    Gavin Peter Lawrence

    2012-11-01

    Full Text Available Research suggests that implicit strategies adopted during learning help prevent breakdown of automatic processes and subsequent performance decrements associated with the presence of pressure. According to the Constrained Action Hypothesis, automaticity of movement is promoted when adopting an external focus of attention. The purpose of the current experiment was to investigate if learning with an external focus of attention can enhance performance under subsequent pressure situations through promoting implicit learning and automaticity. Since previous research has generally used outcome measures of performance, the current study adopted measures of movement production. Specifically, we calculated within subject variability in trajectory velocity and distance travelled every 10% of movement time. This detailed kinematic analysis allowed investigation into some of the previously unexplored mechanisms responsible for the benefits of adopting an external focus of attention. Novice participants performed a 2.5m golf putt. Following a pre-test, participants were randomly assigned to one of three focus groups (internal, external, control. Participants then completed 400 acquisition trials over two consecutive days before being subjected to both a low-anxiety and high-anxiety transfer test. Dependent variables included variability, number of successful putts and mean radial error. Results revealed that variability was greater in the internal compared to the external and control groups. Putting performance revealed that all groups increased performance following acquisition. However, only the control group demonstrated a decrement in performance in the high-anxiety transfer test. These findings suggest that adopting an appropriate focus of attention during learning can prevent choking; with an external focus inhibiting the breakdown of automatic processes and an internal focus acting as a self-focus learning strategy and thus desensitizing individuals

  16. The Functional Task Test (FTT): An Interdisciplinary Testing Protocol to Investigate the Factors Underlying Changes in Astronaut Functional Performance

    Science.gov (United States)

    Bloomberg, J. J.; Lawrence, E. L.; Arzeno, N. M.; Buxton, R. E.; Feiveson, A. H.; Kofman, I. S.; Lee, S. M. C.; Mulavara, A. P.; Peters, B. T.; Platts. S. H.; hide

    2011-01-01

    Exposure to space flight causes adaptations in multiple physiological systems including changes in sensorimotor, cardiovascular, and neuromuscular systems. These changes may affect a crewmember s ability to perform critical mission tasks immediately after landing on a planetary surface. The overall goal of this project is to determine the effects of space flight on functional tests that are representative of high priority exploration mission tasks and to identify the key underlying physiological factors that contribute to decrements in performance. To achieve this goal we developed an interdisciplinary testing protocol (Functional Task Test, FTT) that evaluates both astronaut functional performance and related physiological changes. Functional tests include ladder climbing, hatch opening, jump down, manual manipulation of objects and tool use, seat egress and obstacle avoidance, recovery from a fall and object translation tasks. Physiological measures include assessments of postural and gait control, dynamic visual acuity, fine motor control, plasma volume, orthostatic intolerance, upper- and lower-body muscle strength, power, endurance, control, and neuromuscular drive. Crewmembers perform this integrated test protocol before and after short (Shuttle) and long-duration (ISS) space flight. Data are collected on two sessions before flight, on landing day (Shuttle only) and 1, 6 and 30 days after landing. Preliminary results from both Shuttle and ISS crewmembers indicate decrement in performance of the functional tasks after both short and long-duration space flight. On-going data collection continues to improve the statistical power required to map changes in functional task performance to alterations in physiological systems. The information obtained from this study will be used to design and implement countermeasures that specifically target the physiological systems most responsible for the altered functional performance associated with space flight.

  17. Estimating low-bias frequency response using random decrement

    DEFF Research Database (Denmark)

    Brincker, Rune; Brandt, Anders

    2011-01-01

    It is well known that in order to minimize the influence of leakage bias in frequency response function (FRF) estimates, smooth windows should be applied in the FFT processing. It is also normal practice to use self windowing excitation signals whenever possible. However, in many cases FRFs have...

  18. Decrements in Intrinsic Motivation among Rewarded and Observer Subjects.

    Science.gov (United States)

    Morgan, Mark

    1983-01-01

    Two studies examined the extent to which overjustification effects in five- and ten-year-old subjects can be explained in terms of expectations deriving from the offer of a reward by the experimenter. (Author/MP)

  19. Age-related decrements in cycling and running perfor- mance

    African Journals Online (AJOL)

    Enrique

    12. Skeletal muscle force output capaci- ty remains stable until about the age of 45 years, and then decreases by ~ 10 -15% each decade from the age of about. 50 years.7,10,19. Despite these negative consequences associated with aging ...

  20. Disentangling the cognitive components supporting Austin Maze performance in left versus right temporal lobe epilepsy.

    Science.gov (United States)

    Hocking, Julia; Thomas, Hannah J; Dzafic, Ilvana; Williams, Rebecca J; Reutens, David C; Spooner, Donna M

    2013-12-01

    Neuropsychological tests requiring patients to find a path through a maze can be used to assess visuospatial memory performance in temporal lobe pathology, particularly in the hippocampus. Alternatively, they have been used as a task sensitive to executive function in patients with frontal lobe damage. We measured performance on the Austin Maze in patients with unilateral left and right temporal lobe epilepsy (TLE), with and without hippocampal sclerosis, compared to healthy controls. Performance was correlated with a number of other neuropsychological tests to identify the cognitive components that may be associated with poor Austin Maze performance. Patients with right TLE were significantly impaired on the Austin Maze task relative to patients with left TLE and controls, and error scores correlated with their performance on the Block Design task. The performance of patients with left TLE was also impaired relative to controls; however, errors correlated with performance on tests of executive function and delayed recall. The presence of hippocampal sclerosis did not have an impact on maze performance. A discriminant function analysis indicated that the Austin Maze alone correctly classified 73.5% of patients as having right TLE. In summary, impaired performance on the Austin Maze task is more suggestive of right than left TLE; however, impaired performance on this visuospatial task does not necessarily involve the hippocampus. The relationship of the Austin Maze task with other neuropsychological tests suggests that differential cognitive components may underlie performance decrements in right versus left TLE. © 2013.

  1. Environmental Performance

    DEFF Research Database (Denmark)

    Svabo, Connie; Lindelof, Anja Mølle

    from the perspective of time and liveness as experienced in art on environmental performance discussing how environmental performances frame the temporality of the world. The paper engages with contemporary examples of environmental performances from various disciplines (sound, video, television...

  2. Effects of alcohol on automated and controlled driving performances.

    Science.gov (United States)

    Berthelon, Catherine; Gineyt, Guy

    2014-05-01

    Alcohol is the most frequently detected substance in fatal automobile crashes, but its precise mode of action is not always clear. The present study was designed to establish the influence of blood alcohol concentration as a function of the complexity of the scenarios. Road scenarios implying automatic or controlled driving performances were manipulated in order to identify which behavioral parameters were deteriorated. A single blind counterbalanced experiment was conducted on a driving simulator. Sixteen experienced drivers (25.3 ± 2.9 years old, 8 men and 8 women) were tested with 0, 0.3, 0.5, and 0.8 g/l of alcohol. Driving scenarios varied: road tracking, car following, and an urban scenario including events inspired by real accidents. Statistical analyses were performed on driving parameters as a function of alcohol level. Automated driving parameters such as standard deviation of lateral position measured with the road tracking and car following scenarios were impaired by alcohol, notably with the highest dose. More controlled parameters such as response time to braking and number of crashes when confronted with specific events (urban scenario) were less affected by the alcohol level. Performance decrement was greater with driving scenarios involving automated processes than with scenarios involving controlled processes.

  3. Adaptation and learning: characteristic time scales of performance dynamics.

    Science.gov (United States)

    Newell, Karl M; Mayer-Kress, Gottfried; Hong, S Lee; Liu, Yeou-Teh

    2009-12-01

    A multiple time scales landscape model is presented that reveals structures of performance dynamics that were not resolved in the traditional power law analysis of motor learning. It shows the co-existence of separate processes during and between practice sessions that evolve in two independent dimensions characterized by time scales that differ by about an order of magnitude. Performance along the slow persistent dimension of learning improves often as much and sometimes more during rest (memory consolidation and/or insight generation processes) than during a practice session itself. In contrast, the process characterized by the fast, transient dimension of adaptation reverses direction between practice sessions, thereby significantly degrading performance at the beginning of the next practice session (warm-up decrement). The theoretical model fits qualitatively and quantitatively the data from Snoddy's [Snoddy, G. S. (1926). Learning and stability. Journal of Applied Psychology, 10, 1-36] classic learning study of mirror tracing and other averaged and individual data sets, and provides a new account of the processes of change in adaptation and learning. 2009 Elsevier B.V. All rights reserved.

  4. Kicking velocity and physical, technical, tactical match performance for U18 female football players - effect of a new ball

    DEFF Research Database (Denmark)

    Andersen, Thomas B; Bendiksen, Mads; Pedersen, Jens M

    2012-01-01

    the new ball (NB) compared with the standard ball (SB) in a laboratory testing situation (23.2±0.4 vs. 22.4±0.3 ms(-1); p.05), but lower-limb muscular RPE was lower with NB (4.2±0.4 vs. 5.2±0.3; p.05). High-intensity running decreased (p.05). In conclusion, physiological demands were high in youth female...... football games, and decrements in running performance occurred towards the end of games. The players kicked faster and reported lower muscular exertion during games played with a lighter smaller ball, but locomotor activities, heart rate and overall technical-tactical game performance remained unaffected....

  5. Visual and flight performance recovery after PRK or LASIK in helicopter pilots.

    Science.gov (United States)

    Van de Pol, Corina; Greig, Joanna L; Estrada, Art; Bissette, Gina M; Bower, Kraig S

    2007-06-01

    Refractive surgery, specifically photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK), is becoming more accepted in the military environment. Determination of the impact on visual performance in the more demanding aviation environment was the impetus for this study. A prospective evaluation of 20 Black Hawk pilots pre-surgically and at 1 wk, 1 mo, and 6 mo postsurgery was conducted to assess both PRK and LASIK visual and flight performance outcomes on the return of aviators to duty. Of 20 pilots, 19 returned to flight status at 1 mo after surgery; 1 PRK subject was delayed due to corneal haze and subjective visual symptoms. Improvements were seen under simulator night and night vision goggle flight after LASIK; no significant changes in flight performance were measured in the aircraft. Results indicated a significantly faster recovery of all visual performance outcomes 1 wk after LASIK vs. PRK, with no difference between procedures at 1 and 6 mo. Low contrast acuity and contrast sensitivity only weakly correlated to flight performance in the early post-operative period. Overall flight performance assessed in this study after PRK and LASIK was stable or improved from baseline, indicating a resilience of performance despite measured decrements in visual performance, especially in PRK. More visually demanding flight tasks may be impacted by subtle changes in visual performance. Contrast tests are more sensitive to the effects of refractive surgical intervention and may prove to be a better indicator of visual recovery for return to flight status.

  6. Environmental Performance

    DEFF Research Database (Denmark)

    Lindelof, Anja Mølle; Schmidt, Ulrik; Svabo, Connie

    2017-01-01

    Do ants and grasshoppers perform? Do clouds, plants and melting ice? Do skyscrapers, traffic jams and computer vira? And what happens to our understanding of liveness if that is the case? This chapter takes ongoing theoretical disputes about the nature of live performance in performance studies...... as its starting point to investigate liveness within a specific kind of contemporary performance: ‘environmental performances’. Environmental performances are arts practices that take environmental processes as their focus by framing activities of non-human performers such as clouds, wind and weeds - key...

  7. System reliability, performance and trust in adaptable automation.

    Science.gov (United States)

    Chavaillaz, Alain; Wastell, David; Sauer, Jürgen

    2016-01-01

    The present study examined the effects of reduced system reliability on operator performance and automation management in an adaptable automation environment. 39 operators were randomly assigned to one of three experimental groups: low (60%), medium (80%), and high (100%) reliability of automation support. The support system provided five incremental levels of automation which operators could freely select according to their needs. After 3 h of training on a simulated process control task (AutoCAMS) in which the automation worked infallibly, operator performance and automation management were measured during a 2.5-h testing session. Trust and workload were also assessed through questionnaires. Results showed that although reduced system reliability resulted in lower levels of trust towards automation, there were no corresponding differences in the operators' reliance on automation. While operators showed overall a noteworthy ability to cope with automation failure, there were, however, decrements in diagnostic speed and prospective memory with lower reliability. Copyright © 2015. Published by Elsevier Ltd.

  8. Beyond Performance: A Motivational Experiences Model of Stereotype Threat

    Science.gov (United States)

    Thoman, Dustin B.; Smith, Jessi L.; Brown, Elizabeth R.; Chase, Justin; Lee, Joo Young K.

    2013-01-01

    The contributing role of stereotype threat (ST) to learning and performance decrements for stigmatized students in highly evaluative situations has been vastly documented and is now widely known by educators and policy makers. However, recent research illustrates that underrepresented and stigmatized students’ academic and career motivations are influenced by ST more broadly, particularly through influences on achievement orientations, sense of belonging, and intrinsic motivation. Such a focus moves conceptualizations of ST effects in education beyond the influence on a student’s performance, skill level, and feelings of self-efficacy per se to experiencing greater belonging uncertainty and lower interest in stereotyped tasks and domains. These negative experiences are associated with important outcomes such as decreased persistence and domain identification, even among students who are high in achievement motivation. In this vein, we present and review support for the Motivational Experience Model of ST, a self-regulatory model framework for integrating research on ST, achievement goals, sense of belonging, and intrinsic motivation to make predictions for how stigmatized students’ motivational experiences are maintained or disrupted, particularly over long periods of time. PMID:23894223

  9. Acute Ingestion of Caffeinated Chewing Gum Improves Repeated Sprint Performance of Team Sport Athletes With Low Habitual Caffeine Consumption.

    Science.gov (United States)

    Evans, Mark; Tierney, Peter; Gray, Nicola; Hawe, Greg; Macken, Maria; Egan, Brendan

    2018-04-23

    The effects of acute ingestion of caffeine on short-duration high-intensity performance are equivocal, while studies of novel modes of delivery and the efficacy of low doses of caffeine are warranted. The aims of the present study were to investigate the effect of acute ingestion of caffeinated chewing gum on repeated sprint performance (RSP) in team sport athletes, and whether habitual caffeine consumption alters the ergogenic effect, if any, on RSP. A total of 18 male team sport athletes undertook four RSP trials using a 40-m maximum shuttle run test, which incorporates 10 × 40-m sprints with 30 s between the start of each sprint. Each participant completed two familiarization sessions, followed by caffeine (CAF; caffeinated chewing gum; 200 mg caffeine) and placebo (PLA; noncaffeinated chewing gum) trials in a randomized, double-blind manner. RSP, assessed by sprint performance decrement (%), did not differ (p = .209; effect size = 0.16; N = 18) between CAF (5.00 ± 2.84%) and PLA (5.43 ± 2.68%). Secondary analysis revealed that low habitual caffeine consumers (130 mg/day, n = 6; 3.98 ± 2.57% vs. 3.80 ± 1.79%, respectively; p = .684; effect size = 0.08). The data suggest that a low dose of caffeine in the form of caffeinated chewing gum attenuates the sprint performance decrement during RSP by team sport athletes with low, but not moderate-to-high, habitual consumption of caffeine.

  10. Performing Identities

    DEFF Research Database (Denmark)

    von Wallpach, Sylvia; Hemetsberger, Andrea; Espersen, Peter

    2017-01-01

    performative approaches to branding, this study applies a performativity theory perspective. Brand performances—encompassing playing and liking, basement building and showcasing, creating and innovating, community building and facilitating, storytelling, missionizing, and marketplace developing—exhibit generic...

  11. Dj Performance

    DEFF Research Database (Denmark)

    Dj Performance at a late concert at The Hub, Plymouth, in support of Sileni, Superconductor and others.......Dj Performance at a late concert at The Hub, Plymouth, in support of Sileni, Superconductor and others....

  12. Performance analysis

    International Nuclear Information System (INIS)

    2008-05-01

    This book introduces energy and resource technology development business with performance analysis, which has business division and definition, analysis of current situation of support, substance of basic plan of national energy, resource technique development, selection of analysis index, result of performance analysis by index, performance result of investigation, analysis and appraisal of energy and resource technology development business in 2007.

  13. Visual determinants of reduced performance on the Stroop color-word test in normal aging individuals.

    Science.gov (United States)

    van Boxtel, M P; ten Tusscher, M P; Metsemakers, J F; Willems, B; Jolles, J

    2001-10-01

    It is unknown to what extent the performance on the Stroop color-word test is affected by reduced visual function in older individuals. We tested the impact of common deficiencies in visual function (reduced distant and close acuity, reduced contrast sensitivity, and color weakness) on Stroop performance among 821 normal individuals aged 53 and older. After adjustment for age, sex, and educational level, low contrast sensitivity was associated with more time needed on card I (word naming), red/green color weakness with slower card 2 performance (color naming), and reduced distant acuity with slower performance on card 3 (interference). Half of the age-related variance in speed performance was shared with visual function. The actual impact of reduced visual function may be underestimated in this study when some of this age-related variance in Stroop performance is mediated by visual function decrements. It is suggested that reduced visual function has differential effects on Stroop performance which need to be accounted for when the Stroop test is used both in research and in clinical settings. Stroop performance measured from older individuals with unknown visual status should be interpreted with caution.

  14. Performance following a first professional concussion among National Basketball Association players.

    Science.gov (United States)

    Yengo-Kahn, Aaron M; Zuckerman, Scott L; Stotts, Jeff; Zalneraitis, Brian H; Gardner, Ryan M; Kerr, Zachary Y; Solomon, Gary S

    2016-09-01

    Basketball is a physical game played on a hardwood floor among high-jumping athletes at risk for injury. It is currently unknown how sport-related concussion (SRC) affects player performance after injury among professional basketball players. The objective of this study was to explore the impact of SRC on basketball performance among National Basketball Association (NBA) players. A retrospective, archival cohort study was performed that compared NBA player performance following concussion to pre-concussive performance. A comprehensive NBA injury database, compiled from publically available sources, was queried for NBA players who suffered concussion from 2005-06 to 2014-15 (10 seasons). Intra-and inter-player analyses were performed against a matched control group of players who missed playing time for personal reasons. Following application of inclusion/exclusion criteria and a matching process, 51 concussed players and 51 control players were included in analysis. There were no statistically significant decrements in baseline to post-concussion performance metrics in intra-player or player vs. controls after 5 return games. Our findings suggest that at the NBA level, an athlete's performance in the initial 5 games following injury does not suffer from the after-effects of concussive injury. These results may be useful in counseling professional athletes following a concussion.

  15. Performative Work

    DEFF Research Database (Denmark)

    Beunza, Daniel; Ferraro, Fabrizio

    2018-01-01

    by attending to the normative and regulative associations of the device. We theorize this route to performativity by proposing the concept of performative work, which designates the necessary institutional work to enable translation and the subsequent adoption of the device. We conclude by considering...... the implications of performative work for the performativity and the institutional work literatures.......Callon’s performativity thesis has illuminated how economic theories and calculative devices shape markets, but has been challenged for its neglect of the organizational, institutional and political context. Our seven-year qualitative study of a large financial data company found that the company...

  16. Body Unloading Associated with Space Flight and Bed-rest Impacts Functional Performance

    Science.gov (United States)

    Bloomberg, J. J.; Ballard, K. L.; Batson, C. D.; Buxton, R. E.; Feiveson, A. H.; Kofman, I. S.; Lee, S. M. C.; Miller, C. A.; Mulavara, A. P.; Peters, B. T.; hide

    2014-01-01

    The goal of the Functional Task Test study is to determine the effects of space flight on functional tests that are representative of high priority exploration mission tasks and to identify the key underlying physiological factors that contribute to decrements in performance. Ultimately this information will be used to assess performance risks and inform the design of countermeasures for exploration class missions. We are currently conducting studies on both ISS crewmembers and on subjects experiencing 70 days of 6 degrees head-down bed-rest as an analog for space flight. Bed-rest provides the opportunity for us to investigate the role of prolonged axial body unloading in isolation from the other physiological effects produced by exposure to the microgravity environment of space flight. This allows us to parse out the contribution of the body unloading component on functional performance. In this on-going study both ISS crewmembers and bed-rest subjects were tested using an interdisciplinary protocol that evaluated functional performance and related physiological changes before and after 6 months in space and 70 days of 6? head-down bed-rest, respectively. Functional tests included ladder climbing, hatch opening, jump down, manual manipulation of objects and tool use, seat egress and obstacle avoidance, recovery from a fall, and object translation tasks. Crewmembers were tested three times before flight, and on 1, 6 and 30 days after landing. Bed-rest subjects were tested three times before bed-rest and immediately after getting up from bed-rest as well as 1, 6 and 12 days after reambulation. A comparison of bed-rest and space flight data showed a significant concordance in performance changes across all functional tests. Tasks requiring a greater demand for dynamic control of postural equilibrium (i.e. fall recovery, seat egress/obstacle avoidance during walking, object translation, jump down) showed the greatest decrement in performance. Functional tests with

  17. Gender & performance

    NARCIS (Netherlands)

    Röttger, K.; Buchheim, E.; Groot, M.; Jonker, E.; Müller-Schirmer, A.; de Vos, M.; Walhout, E.; van der Zande, H.

    2012-01-01

    This Yearbook for Women’s History (Jaarboek voor Vrouwengeschiedenis) examines the theme of gender and performance. It is supervised by guest editor Kati Röttger, professor in Theatre Studies at the University of Amsterdam. The term performance - a temporary and active presentation, expression, or

  18. Performing compliance

    DEFF Research Database (Denmark)

    Wimmelmann, Camilla Lawaetz

    2017-01-01

    the local policy workers front-staged some practices in the implementation process and back-staged others. The local policy workers deliberately performed ‘guideline compliance’ by using information control and impression management techniques. The findings suggest that local guideline compliance should...... be regarded as a staged performance in which deliberate techniques are used to produce and manage certain impressions of compliance....

  19. School Performance

    Science.gov (United States)

    Lamas, Héctor A.

    2015-01-01

    The school performance study of students is, due to its relevance and complexity, one of the issues of major controversy in the educational research, and it has been given special attention in the last decades. This study is intended to show a conceptual approach to the school performance construct, contextualizing the reality in the regular basic…

  20. Fabrication and Performance of a Lithium X-Ray Lens

    Science.gov (United States)

    Young, Kristina; Khounsary, Ali; Jansen, Andrew N.; Dufresne, Eric M.; Nash, Philip

    2007-01-01

    Compound refractive lenses (CRLs) are arrays of concave lenses whose simple design and ease in implementation and alignment make them an attractive optic to focus x-rays. Factors considered in designing CRLs include lens material, fabrication, and assembly. Lithium is a desirable material because it provides the largest index of refraction decrement per unit absorption length of any solid elements. Lithium is a difficult material to handle and fabricate because it is rather malleable and more importantly, it reacts with moisture, and to a lesser extent, with oxygen and nitrogen in air. It also tends to adhere to molds and dies. We report on the fabrication and performance of a parabolic lithium lens consisting of 32 lenslets. Lenslets are fabricated in a precision press using an indenter with a parabolic profile and a 100 μm tip radius. The indenter is made of stainless steel and is figured using a computer numerically controlled (CNC) machine. The lens is designed to have a 1.7 m focal length at 10 keV energy. In an experiment conducted at the Advanced Photon Source (APS), a 0.5 mm × 0.5 mm monochromatic undulator beam strikes the lens. A focal length of 1.71, a focal spot size of 24 μm × 34 μm, and a peak intensity gain of over 18 are obtained.

  1. Fabrication and Performance of a Lithium X-Ray Lens

    International Nuclear Information System (INIS)

    Young, Kristina; Khounsary, Ali; Jansen, Andrew N.; Dufresne, Eric M.; Nash, Philip

    2007-01-01

    Compound refractive lenses (CRLs) are arrays of concave lenses whose simple design and ease in implementation and alignment make them an attractive optic to focus x-rays. Factors considered in designing CRLs include lens material, fabrication, and assembly. Lithium is a desirable material because it provides the largest index of refraction decrement per unit absorption length of any solid elements. Lithium is a difficult material to handle and fabricate because it is rather malleable and more importantly, it reacts with moisture, and to a lesser extent, with oxygen and nitrogen in air. It also tends to adhere to molds and dies.We report on the fabrication and performance of a parabolic lithium lens consisting of 32 lenslets. Lenslets are fabricated in a precision press using an indenter with a parabolic profile and a 100 μm tip radius. The indenter is made of stainless steel and is figured using a computer numerically controlled (CNC) machine. The lens is designed to have a 1.7 m focal length at 10 keV energy. In an experiment conducted at the Advanced Photon Source (APS), a 0.5 mm x 0.5 mm monochromatic undulator beam strikes the lens. A focal length of 1.71, a focal spot size of 24 μm x 34 μm, and a peak intensity gain of over 18 are obtained

  2. Aesthetic Performance

    DEFF Research Database (Denmark)

    Landgrebe, Jeanette

    2013-01-01

    -verbal actions, gaze orientation, active and static interactional strategies and props. From the data investigated, it seems that the performance act is divided into different stages which each calls for different strategies: the group's initiation of the entire performance act reveals that the group stand out......This article deals with how an aesthetic performance is enacted and coordinated by a performance group attracting attention and engaging commuters in a public space. Multimodal interactional resources and the way they are coordinated by interactants are investigated, and include verbal and non...... as uncoordinated and it may have a significance for whether the 'street' performers manage to stay in character or not. Once attention from commuters is obtained, a continued gaze from these commuters opens up for subsequent interaction, which then ultimately may result in the successful handing over of a card...

  3. Organizational Performance

    Directory of Open Access Journals (Sweden)

    Renata Peregrino de Brito

    2016-01-01

    Full Text Available This paper presents a theoretical and empirical analysis of the relationship between human resource management (HRM and organizational performance. Theoretically, we discuss the importance of HRM for the development of resources and its impact on business performance. Empirically, we evaluated articles published on Brazilian academic journals that addressed such relationships. The results showed a lack of studies conducted at this intersection. From the universe of 2,469 articles, only 16 (0.6% sought to relate HRM and organizational performance. We observed a dominance of isolated HR practices, which does not consider HRM as a system, and of operational performance measures, relative to financial and efficiency variables. Most studies show a positive relationship between HRM practices and performance, in line with the literature. However, we point out some methodological issues, such as the difficulty of isolating the HR practices from its context, the failure to consider the temporality of this relationship, and the comparison between companies from different industries.

  4. School Performance

    Directory of Open Access Journals (Sweden)

    Héctor A. Lamas

    2015-03-01

    Full Text Available The school performance study of students is, due to its relevance and complexity, one of the issues of major controversy in the educational research, and it has been given special attention in the last decades. This study is intended to show a conceptual approach to the school performance construct, contextualizing the reality in the regular basic education classrooms. The construct of learning approaches is presented as one of the factors that influences the school performance of students. Besides, an outlook of the empirical research works related to variables that are presented as relevant when explaining the reason for a specific performance in students is shown. Finally, some models and techniques allowing an appropriate study of school performance are presented.

  5. Study on Performance Shaping Factors (PSFs) Quantification Method in Human Reliability Analysis (HRA)

    International Nuclear Information System (INIS)

    Kim, Ar Ryum; Jang, Inseok Jang; Seong, Poong Hyun; Park, Jinkyun; Kim, Jong Hyun

    2015-01-01

    The purpose of HRA implementation is 1) to achieve the human factor engineering (HFE) design goal of providing operator interfaces that will minimize personnel errors and 2) to conduct an integrated activity to support probabilistic risk assessment (PRA). For these purposes, various HRA methods have been developed such as technique for human error rate prediction (THERP), simplified plant analysis risk human reliability assessment (SPAR-H), cognitive reliability and error analysis method (CREAM) and so on. In performing HRA, such conditions that influence human performances have been represented via several context factors called performance shaping factors (PSFs). PSFs are aspects of the human's individual characteristics, environment, organization, or task that specifically decrements or improves human performance, thus respectively increasing or decreasing the likelihood of human errors. Most HRA methods evaluate the weightings of PSFs by expert judgment and explicit guidance for evaluating the weighting is not provided. It has been widely known that the performance of the human operator is one of the critical factors to determine the safe operation of NPPs. HRA methods have been developed to identify the possibility and mechanism of human errors. In performing HRA methods, the effect of PSFs which may increase or decrease human error should be investigated. However, the effect of PSFs were estimated by expert judgment so far. Accordingly, in order to estimate the effect of PSFs objectively, the quantitative framework to estimate PSFs by using PSF profiles is introduced in this paper

  6. The effects of voice and manual control mode on dual task performance

    Science.gov (United States)

    Wickens, C. D.; Zenyuh, J.; Culp, V.; Marshak, W.

    1986-01-01

    Two fundamental principles of human performance, compatibility and resource competition, are combined with two structural dichotomies in the human information processing system, manual versus voice output, and left versus right cerebral hemisphere, in order to predict the optimum combination of voice and manual control with either hand, for time-sharing performance of a dicrete and continuous task. Eight right handed male subjected performed a discrete first-order tracking task, time-shared with an auditorily presented Sternberg Memory Search Task. Each task could be controlled by voice, or by the left or right hand, in all possible combinations except for a dual voice mode. When performance was analyzed in terms of a dual-task decrement from single task control conditions, the following variables influenced time-sharing efficiency in diminishing order of magnitude, (1) the modality of control, (discrete manual control of tracking was superior to discrete voice control of tracking and the converse was true with the memory search task), (2) response competition, (performance was degraded when both tasks were responded manually), (3) hemispheric competition, (performance degraded whenever two tasks were controlled by the left hemisphere) (i.e., voice or right handed control). The results confirm the value of predictive models invoice control implementation.

  7. Performance managenemt

    DEFF Research Database (Denmark)

    Jacobi, Claus Brygger

    This paper attempts to identify barriers that prevent performance management from being genuinely result-based. By observing what happened when a Danish workfare reform was implemented by applying performance management, it becomes apparent that there exists internal decouplings on and between two...... levels; a decoupling between the monitoring/evaluation of established performance indicators and the revising of these for policy-making on future interventions, and a decoupling between the strategic political/administrative level and operational street-level, inhibiting its adaption to local...

  8. A Monetary Reward Alters Pacing but Not Performance in Competitive Cyclists.

    Science.gov (United States)

    Skorski, Sabrina; Thompson, Kevin G; Keegan, Richard J; Meyer, Tim; Abbiss, Chris R

    2017-01-01

    Money has frequently been used as an extrinsic motivator since it is assumed that humans are willing to invest more effort for financial reward. However, the influence of a monetary reward on pacing and performance in trained athletes is not well-understood. Therefore, the aim of this study was to analyse the influence of a monetary reward in well-trained cyclists on their pacing and performance during short and long cycling time trials (TT). Twentythree cyclists (6 ♀, 17 ♂) completed 4 self-paced time trials (TTs, 2 short: 4 km and 6 min; 2 long: 20 km and 30 min); in a randomized order. Participants were separated into parallel, non-randomized "rewarded" and "non-rewarded" groups. Cyclists in the rewarded group received a monetary reward based on highest mean power output across all TTs. Cyclists in the non-rewarded group did not receive a monetary reward. Overall performance was not significantly different between groups in short or long TTs ( p > 0.48). Power output showed moderatly lower effect sizes at comencement of the short TTs ( P meandiff = 36.6 W; d > 0.44) and the 20 km TT ( P meandiff = 22.6 W; d = 0.44) in the rewarded group. No difference was observed in pacing during the 30 min TT ( p = 0.95). An external reward seems to have influenced pacing at the commencement of time trials. Participants in the non-rewarded group adopted a typical parabolic shaped pattern, whereas participants in the rewarded group started trials more conservatively. Results raise the possibility that using money as an extrinsic reward may interfere with regulatory processes required for effective pacing.

  9. A Monetary Reward Alters Pacing but Not Performance in Competitive Cyclists

    Directory of Open Access Journals (Sweden)

    Sabrina Skorski

    2017-09-01

    Full Text Available Money has frequently been used as an extrinsic motivator since it is assumed that humans are willing to invest more effort for financial reward. However, the influence of a monetary reward on pacing and performance in trained athletes is not well-understood. Therefore, the aim of this study was to analyse the influence of a monetary reward in well-trained cyclists on their pacing and performance during short and long cycling time trials (TT. Twentythree cyclists (6 ♀, 17 ♂ completed 4 self-paced time trials (TTs, 2 short: 4 km and 6 min; 2 long: 20 km and 30 min; in a randomized order. Participants were separated into parallel, non-randomized “rewarded” and “non-rewarded” groups. Cyclists in the rewarded group received a monetary reward based on highest mean power output across all TTs. Cyclists in the non-rewarded group did not receive a monetary reward. Overall performance was not significantly different between groups in short or long TTs (p > 0.48. Power output showed moderatly lower effect sizes at comencement of the short TTs (Pmeandiff = 36.6 W; d > 0.44 and the 20 km TT (Pmeandiff = 22.6 W; d = 0.44 in the rewarded group. No difference was observed in pacing during the 30 min TT (p = 0.95. An external reward seems to have influenced pacing at the commencement of time trials. Participants in the non-rewarded group adopted a typical parabolic shaped pattern, whereas participants in the rewarded group started trials more conservatively. Results raise the possibility that using money as an extrinsic reward may interfere with regulatory processes required for effective pacing.

  10. Performative Environments

    DEFF Research Database (Denmark)

    Thomsen, Bo Stjerne

    2008-01-01

    The paper explores how performative architecture can act as a collective environment localizing urban flows and establishing public domains through the integration of pervasive computing and animation techniques. The NoRA project introduces the concept of ‘performative environments,' focusing on ...... of local interactions and network behaviour, building becomes social infrastructure and prompts an understanding of architectural structures as quasiobjects, which can retain both variation and recognisability in changing social constellations.......The paper explores how performative architecture can act as a collective environment localizing urban flows and establishing public domains through the integration of pervasive computing and animation techniques. The NoRA project introduces the concept of ‘performative environments,' focusing...

  11. Effects of Aging on Musical Performance in Professional Orchestral Musicians.

    Science.gov (United States)

    Kenny, Dianna T; Driscoll, Tim; Ackermann, Bronwen J

    2018-03-01

    The physical and psychological demands of playing a musical instrument are likely to be affected by age-related decline in function, including physical, cognitive, psychological, and organ-related changes. However, the complex neurophysiological demands of playing a musical instrument may delay many normal aging-related changes. This study compared professional classical musicians of different ages, using a range of physical and psychological measures, to discover how increasing age might affect work performance and to identify possible risk and protective factors for physical and psychological health as the musicians age. 377 professional orchestral musicians from eight Australian orchestras (70% response rate), ages 18 to 68 yrs (mean 42.1). Multiple standardized physical and psychological tools were used to evaluate the impact of age on a range of physical and mental health variables. Age was not statistically associated with frequency or severity of performance-related musculoskeletal disorders, ratings of perceived exertion, QuickDASH scores, use of beta-blockers, workplace satisfaction, and most psychological tests. Differences were observed on SPIN (social anxiety) scores, with lowest scores in the oldest age group (10.66 in 55+ yrs vs 17.83 in 18-30 yrs, p=0.016). Older musicians had higher BMIs and fewer practice sessions per day than younger musicians and also were more likely to consume alcohol on 5+ days/wk (44% vs 9%, p=0.003). Advancing age does not appear to exert undue negative impacts on physical and psychological health or performance capacity of professional orchestral musicians. However, dwindling numbers in the older age groups may suggest a "survivor" effect, whereby those who develop significant age-related decrements may cease professional performance at earlier ages. Longitudinal studies on the professional trajectories of professional orchestral musicians are needed to explore this question further.

  12. Influence of AlGaN/GaN superlattice inserted structure on the performance of InGaN/GaN multiple quantum well light emitting diodes

    International Nuclear Information System (INIS)

    Wang, C.-L.; Tsai, M.-C.; Gong, J.-R.; Liao, W.-T.; Lin, P.-Y.; Yen, K.-Y.; Chang, C.-C.; Lin, H.-Y.; Hwang, S.-K.

    2007-01-01

    Investigations were conducted to explore the effect of Al 0.3 Ga 0.7 N/GaN short-period superlattice (SPSL)-inserted structures in the GaN under layer on the performance of In 0.2 Ga 0.8 N/GaN multiple quantum well (MQW) light emitting diodes (LEDs). The Al 0.3 Ga 0.7 N/GaN SPSL-inserted LEDs were found to exhibit improved materials and device characteristics including decrements in ideality factor and reverse leakage current. The results of etch pit counts reveal that SPSL-induced threading dislocation density reduction in the SPSL-inserted In 0.2 Ga 0.8 N/GaN MQW LED structures enables the improved LED performance

  13. Exposure to Psychological Aggression at Work and Job Performance: The Mediating Role of Job Attitudes and Personal Health.

    Science.gov (United States)

    Schat, Aaron; Frone, Michael R

    2011-01-01

    Despite the growing literature on workplace aggression and the importance of employee performance at work, few studies have examined the relation between workplace aggression and job performance. The purpose of this study was to investigate the relations between psychological aggression at work and two forms of job performance (task performance and contextual performance) and potential mediators of these relations. Based on Conservation of Resources theory and prior research, a model was developed and tested in which overall job attitudes (i.e., job satisfaction and organizational commitment) and overall personal health (i.e., physical and psychological health) fully mediate the relations between exposure to psychological aggression at work and both task performance and contextual performance. Data were obtained from a national probability sample of US workers (N = 2376) and the model was tested using structural equation modelling. The results supported the hypothesized model, demonstrating that exposure to psychological aggression at work negatively predicted both task performance and contextual performance, and that these relations were explained by decrements in job attitudes and health associated with exposure to psychological aggression at work.

  14. Encoding vs. retention: differential effects of cue manipulation on working memory performance in schizophrenia.

    Science.gov (United States)

    Javitt, Daniel C; Rabinowicz, Esther; Silipo, Gail; Dias, Elisa C

    2007-03-01

    Deficits in working memory performance are among the most widely replicated findings in schizophrenia. Roles of encoding vs. memory retention in working memory remain unresolved. The present study evaluated working memory performance in schizophrenia using an AX-type continuous performance test (AX-CPT) paradigm. Participants included 48 subjects with schizophrenia and 27 comparison subjects. Behavior was obtained in 3 versions of the task, which differed based upon ease of cue interoperability. In a simple cue version of the task, cue letters were replaced with red or green circles. In the complex cue version, letter/color conjunctions served as cues. In the base version of the task, patients showed increased rates of false alarms to invalidly cued targets, similar to prior reports. However, when the cue stimuli were replaced with green or red circles to ease interpretation, patients showed similar false alarm rates to controls. When feature conjunction cues were used, patients were also disproportionately affected relative to controls. No significant group by interstimulus interval interaction effects were observed in either the simple or complex cue conditions, suggesting normal retention of information even in the presence of overall performance decrements. These findings suggest first, that cue manipulation disproportionately affects AX-CPT performance in schizophrenia and, second, that substantial behavioral deficits may be observed on working memory tasks even in the absence of disturbances in mnemonic retention.

  15. The disruptive effects of pain on complex cognitive performance and executive control.

    Directory of Open Access Journals (Sweden)

    Edmund Keogh

    Full Text Available Pain interferes and disrupts attention. What is less clear is how pain affects performance on complex tasks, and the strategies used to ensure optimal outcomes. The aim of the current study was to examine the effect of pain on higher-order executive control processes involved in managing complex tasks. Sixty-two adult volunteers (40 female completed two computer-based tasks: a breakfast making task and a word generation puzzle. Both were complex, involving executive control functions, including goal-directed planning and switching. Half of those recruited performed the tasks under conditions of thermal heat pain, and half with no accompanying pain. Whilst pain did not affect central performance on either task, it did have indirect effects. For the breakfast task, pain resulted in a decreased ability to multitask, with performance decrements found on the secondary task. However, no effects of pain were found on the processes thought to underpin this task. For the word generation puzzle, pain did not affect task performance, but did alter subjective accounts of the processes used to complete the task; pain affected the perceived allocation of time to the task, as well as switching perceptions. Sex differences were also found. When studying higher-order cognitive processes, pain-related interference effects are varied, and may result in subtle or indirect changes in cognition.

  16. The disruptive effects of pain on complex cognitive performance and executive control.

    Science.gov (United States)

    Keogh, Edmund; Moore, David J; Duggan, Geoffrey B; Payne, Stephen J; Eccleston, Christopher

    2013-01-01

    Pain interferes and disrupts attention. What is less clear is how pain affects performance on complex tasks, and the strategies used to ensure optimal outcomes. The aim of the current study was to examine the effect of pain on higher-order executive control processes involved in managing complex tasks. Sixty-two adult volunteers (40 female) completed two computer-based tasks: a breakfast making task and a word generation puzzle. Both were complex, involving executive control functions, including goal-directed planning and switching. Half of those recruited performed the tasks under conditions of thermal heat pain, and half with no accompanying pain. Whilst pain did not affect central performance on either task, it did have indirect effects. For the breakfast task, pain resulted in a decreased ability to multitask, with performance decrements found on the secondary task. However, no effects of pain were found on the processes thought to underpin this task. For the word generation puzzle, pain did not affect task performance, but did alter subjective accounts of the processes used to complete the task; pain affected the perceived allocation of time to the task, as well as switching perceptions. Sex differences were also found. When studying higher-order cognitive processes, pain-related interference effects are varied, and may result in subtle or indirect changes in cognition.

  17. Performance assessment

    International Nuclear Information System (INIS)

    Doe, T.

    1985-01-01

    The purpose of performance assessment is to show that the repository is expected to serve its stated function - disposing of radioactive waste safely both during operation and for the postclosure period. Performance assessment is a straightforward concept, but its application may be very complicated. The concept of performance assessment has been clarified by the Nuclear Regulatory Commission (NRC) in their Draft Generic Technical Position on Licensing Assessment Methodology for High-Level Waste Geologic Repositories (NRC, 1984). This document has gone a long way toward defining the criteria that the NRC will use to determine whether or not information from site characterization is adequate to meet the regulations of the Nuclear Regulatory Commission and the Environmental Protection Agency (EPA). A favorable determination is required for issuance of a construction authorization, which is the first major regulatory requirement for developing a working repository. It is, therefore, essential that a research program be developed that not only resolves the outstanding technical issues, but also does it in such a way that the results are clearly applicable to the formal performance assessment and licensing procedures. The definitions of performance assessment are reviewed and the current NRC thinking is summarized

  18. Performative Silences

    DEFF Research Database (Denmark)

    Dupret, Katia

    2018-01-01

    static nor neutral. It has performative effects. Silencing as an act, rather than a noun, is conceptualised as a central ‘configurating actor’ of change. Through the description of minute details from a videotaped supervision session in the mental healthcare sector, it is shown how different performative...... configurations of silence makes people relate to each other in new ways and influence new work practices. In spite of its somewhat immaterial connotations, using an Actor-Network Theory approach to organization studies, silencing is conceptualised as both a means and an effect of change efforts, which are socio...

  19. Performing Brexit

    DEFF Research Database (Denmark)

    Adler-Nissen, Rebecca; Galpin, Charlotte; Rosamond, Ben

    2017-01-01

    constructed from the outside. Brexit signifies more than the technical complexities of the UK withdrawing from the European Union. It works both as a promise of a different future and performatively to establish a particular past. Brexit works as a frame with potential to shape perceptions in three domains...

  20. Performance Design

    DEFF Research Database (Denmark)

    Svabo, Connie

    Contribution to conference: Art and Presence The emerging field of Performance Design is unfolded as a bastard form of research/art/design/practice, with shapeshifting, monstruous, hybrid and transformational qualities. The potential for presencing, which emerges out of momentarily transgressing...

  1. Operator performance on the night shift: phases 1 and 2

    International Nuclear Information System (INIS)

    Morisseau, Dolores; Beere, Barnaby; Collier, Steve

    1999-04-01

    The objective of the project on operator performance on the night shift is to determine the effects of circadian rhythms on higher order cognitive processes. The project had two preliminary phases. Subjects were operators from the Halden Boiling Water Reactor, (Phase 1: 7 male operators and shift leaders, aged 26 to 35; Phase 2: 8 male operators and shift leaders, aged 26 to 53). The majority of the operators were the same for both studies. The preliminary work established that Norwegian operators' circadian rhythms fall within universal population norms and, thus, they are suitable subjects for such experiments. During Phase 1, two self-assessment instruments, the Stanford Sleepiness Scale (SSS) and the Global Vigour and Affect Scale (GVA), were administered every hour on all three shifts at the reactor. During Phase 2, three tests from the Walter Reed Performance Assessment Battery were administered at the beginning, middle, and end of each of the three shifts at the reactor. The tests (Serial Add-Subtract, Two-Column Addition, and Logical Reasoning) were administered using a hand-held computer. Both phases were conducted during regular work shifts for one complete shift rota (six weeks). ANOVA with two repeated measures showed that self-reported sleepiness on the night shift, sleepiness with respect to hours into the shift, and the interaction between them all reached statistical significance at p<.001. Data analyses (ANOVA) from Phase 2 indicate that the main effect of SHIFTNO (morning, afternoon, evening) on response times was significant (p<.002); the interaction between SHIFTNO and TINSHIFT (hours into shift) was also significant (p<.009). None of the effects on correctness of response was significant (Phase 2). While correctness of response was not significant for routine cognitive measures, the significant, progressive slowing of response times on the night shift reinforces the concern for possible performance decrements on the night shift. Thus, it

  2. Enhanced emotional interference on working memory performance in adults with ADHD.

    Science.gov (United States)

    Marx, Ivo; Domes, Gregor; Havenstein, Carolin; Berger, Christoph; Schulze, Lars; Herpertz, Sabine C

    2011-09-01

    Subjects with attention-deficit/hyperactivity disorder (ADHD) suffer from both executive dysfunction and deficits in emotion regulation. However, up to now, there has been no research demonstrating a clear impact of emotional dysregulation on cognitive performance in subjects with ADHD. Male and female adults with ADHD (n=39) and gender- and IQ-matched control subjects (n=40) performed an emotional working memory task (n-back task). In the background of the task, we presented neutral and negative stimuli varied in emotional saliency (negative pictures with low saliency, negative pictures with high saliency), but subjects were instructed to ignore these pictures and to process the working memory task as quickly and as accurately as possible. Compared to control subjects, ADHD patients showed both a general working memory deficit and enhanced distractability by emotionally salient stimuli in terms of lower n-back performance accuracy. In particular, while controls showed impaired WM performance when presented with highly arousing negative background pictures, a comparable decrement was observed in the ADHD group already with lowly arousing pictures. Our results suggest that difficulties in suppressing attention towards emotionally laden stimuli might result from deficient executive control in ADHD.

  3. Inhibition of hippocampal aromatization impairs spatial memory performance in a male songbird.

    Science.gov (United States)

    Bailey, David J; Ma, Chunqi; Soma, Kiran K; Saldanha, Colin J

    2013-12-01

    Recent studies have revealed the presence and regulation of aromatase at the vertebrate synapse, and identified a critical role played by presynaptic estradiol synthesis in the electrophysiological response to auditory and other social cues. However, if and how synaptic aromatization affects behavior remains to be directly tested. We have exploited 3 characteristics of the zebra finch hippocampus (HP) to test the role of synaptocrine estradiol provision on spatial memory function. Although the zebra finch HP contains abundant aromatase transcripts and enzyme activity, immunocytochemical studies reveal widespread pre- and postsynaptic, but sparse to undetectable somal, localization of this enzyme. Further, the superficial location of the avian HP makes possible the more exclusive manipulation of its neurochemical characteristics without perturbation of the neuropil and the resultant induction of astroglial aromatase. Last, as in other vertebrates, the HP is critical for spatial memory performance in this species. Here we report that local inhibition of hippocampal aromatization impairs spatial memory performance in an ecologically valid food-finding task. Local aromatase inhibition also resulted in lower levels of estradiol in the HP, but not in adjacent brain areas, and was achieved without the induction of astroglial aromatase. The observed decrement in acquisition and subsequent memory performance as a consequence of lowered aromatization was similar to that achieved by lesioning this locus. Thus, hippocampal aromatization, much of which is achieved at the synapse in this species, is critical for spatial memory performance.

  4. Non-Pharmacological Countermeasure to Decrease Landing Sickness and Improve Functional Performance

    Science.gov (United States)

    Rosenberg, M. J. F.; Kreutzberg, G. A.; Galvan-Garza, R. C.; Mulavara, A. P.; Reschke, M. F.

    2017-01-01

    Upon return from long-duration spaceflight, 100% of crewmembers experience motion sickness (MS) symptoms. The interactions between crewmembers' adaptation to a gravitational transition, the performance decrements resulting from MS and/or use of promethazine (PMZ), and the constraints imposed by mission task demands could significantly challenge and limit an astronaut's ability to perform functional tasks during gravitational transitions. Stochastic resonance (SR) is "noise benefit": adding noise to a system might increase the information (examples to the left and above). Stochastic vestibular stimulation (SVS), or low levels of noise applied to the vestibular system, improves balance and locomotor performance (Goel et al. 2015, Mulavara et al. 2011, 2015). In hemi-lesioned rat models, Samoudi et al. 2012 found that SVS increased GABA release on the lesioned, but not the intact side. Activation of the GABA pathway is important in modulating MS and promoting adaptability (Cohen 2008) and was seen to reverse MS symptoms in rats after unilateral labyrinthectomy (Magnusson et al. 2000). Thus, SVS could be used to promote GABA pathways to reduce MS and promote adaptability, eliminate the need for PMZ or other performance-inhibiting drugs.

  5. The Nursing Performance Instrument: Exploratory and Confirmatory Factor Analyses in Registered Nurses.

    Science.gov (United States)

    Sagherian, Knar; Steege, Linsey M; Geiger-Brown, Jeanne; Harrington, Donna

    2018-04-01

    The optimal performance of nurses in healthcare settings plays a critical role in care quality and patient safety. Despite this importance, few measures are provided in the literature that evaluate nursing performance as an independent construct from competencies. The nine-item Nursing Performance Instrument (NPI) was developed to fill this gap. The aim of this study was to examine and confirm the underlying factor structure of the NPI in registered nurses. The design was cross-sectional, using secondary data collected between February 2008 and April 2009 for the "Fatigue in Nursing Survey" (N = 797). The sample was predominantly dayshift female nurses working in acute care settings. Using Mplus software, exploratory and confirmatory factor analyses were applied to the NPI data, which were divided into two equal subsamples. Multiple fit indices were used to evaluate the fit of the alternative models. The three-factor model was determined to fit the data adequately. The factors that were labeled as "physical/mental decrements," "consistent practice," and "behavioral change" were moderately to strongly intercorrelated, indicating good convergent validity. The reliability coefficients for the subscales were acceptable. The NPI consists of three latent constructs. This instrument has the potentialto be used as a self-monitoring instrument that addressesnurses' perceptions of performance while providing patient care.

  6. Memory performance in abstinent 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") users.

    Science.gov (United States)

    Groth-Marnat, Gary; Howchar, Hennedy; Marsh, Ali

    2007-02-01

    Research with animals and humans has suggested that acute and subacute use of 3,4-methylenedioxymethamphetamine (MDMA "ecstasy") may lead to memory impairment. However, research is limited by (1) low power due to small sample sizes, (2) the possible confound of polydrug use, and (3) the failure to consider intelligence as a covariate. The present study compared the memory performance on the Wechsler Memory Scale-III of 26 abstinent (2-wk. minimum) recreational MDMA users with 26 abstinent (2-wk. minimum) recreational polydrug users. Despite significantly greater polydrug use amongst these MDMA users, no significant group differences in memory were observed. Regression of total lifetime amount of MDMA use also did not predict memory performance after accounting for intelligence. In addition, the length of time since abstinence (at least 2 wk.) was not associated with an increase in memory performance. Greater total lifetime cocaine use, rather than total lifetime MDMA use, was significantly associated with greater decrements in General Memory and Delayed Verbal Memory performance.

  7. Urban performances

    DEFF Research Database (Denmark)

    Samson, Kristine

    2012-01-01

    Through three different urban performances, the paper investigates how, when and under which circumstances urban space is transformed and distorted from its every day use and power relations. Distortion is an annual street festival in Copenhagen with the objective to distort the functional city...... creates an intensive space for the empowerment and liberation of the body. Occupy Wall street and its action in the autumn 2001 is the ultimate example of how urban political performances intensifies and transform every day spaces. Through examples of how OWS tactically appropriates and transforms urban...... space, I seek to show how representational space, for instance the public square, is transformed and distorted by heterogeneous and unforeseen modes of operating. Despite differing in their goal and outset, I wish to unfold an alternative to urban transformation practices in planning and architecture...

  8. Performative securitization

    DEFF Research Database (Denmark)

    Philipsen, Lise

    2018-01-01

    This piece develops a performative take on securitization theory. It argues that rather than seeing authority as a prerequisite for speaking security, we need to zoom in on how speaking security can be used to claim authority. Such acts of claiming authority are crucial to understand the current...... challenged and changed. Two, following Butler, we must open up who can speak security, seeing how speaking security can be used to take authority, rather than seeing authority as a precondition for speaking security....

  9. ORELA performance

    International Nuclear Information System (INIS)

    Lewis, T.A.

    1976-04-01

    The most recent information concerning the performance of ORELA that would be of interest to experimenters is presented. Included are characteristics of the beam in terms of both time and intensity and descriptions of systems routinely used to monitor these beam characteristics. For example, with klystron power and maximum electron gun output current at nominal values and for pulse repetition rates in the range above 800 pps, output beam energies per pulse vary from 5 J for 2.5 nsec-wide pulses to approximately 32 J for 10 nsec pulses and 65 J for 40 nsec pulses

  10. Brain mechanisms of self-control: A neurocognitive investigation of reward-based action control and error awareness

    NARCIS (Netherlands)

    Harsay, H.A.

    2014-01-01

    Motivation and the ability to detect errors are critical for the interaction with our environment. They provide us with the opportunity to engage in purposive, persistent and corrective behavior, and to take the consequences of our actions into account. Diminished motivation and error awareness have

  11. From conflict management to reward-based decision making: actors and critics in primate medial frontal cortex.

    Science.gov (United States)

    Silvetti, Massimo; Alexander, William; Verguts, Tom; Brown, Joshua W

    2014-10-01

    The role of the medial prefrontal cortex (mPFC) and especially the anterior cingulate cortex has been the subject of intense debate for the last decade. A number of theories have been proposed to account for its function. Broadly speaking, some emphasize cognitive control, whereas others emphasize value processing; specific theories concern reward processing, conflict detection, error monitoring, and volatility detection, among others. Here we survey and evaluate them relative to experimental results from neurophysiological, anatomical, and cognitive studies. We argue for a new conceptualization of mPFC, arising from recent computational modeling work. Based on reinforcement learning theory, these new models propose that mPFC is an Actor-Critic system. This system is aimed to predict future events including rewards, to evaluate errors in those predictions, and finally, to implement optimal skeletal-motor and visceromotor commands to obtain reward. This framework provides a comprehensive account of mPFC function, accounting for and predicting empirical results across different levels of analysis, including monkey neurophysiology, human ERP, human neuroimaging, and human behavior. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. The alcoholic brain: neural bases of impaired reward-based decision-making in alcohol use disorders.

    Science.gov (United States)

    Galandra, Caterina; Basso, Gianpaolo; Cappa, Stefano; Canessa, Nicola

    2018-03-01

    Neuroeconomics is providing insights into the neural bases of decision-making in normal and pathological conditions. In the neuropsychiatric domain, this discipline investigates how abnormal functioning of neural systems associated with reward processing and cognitive control promotes different disorders, and whether such evidence may inform treatments. This endeavor is crucial when studying different types of addiction, which share a core promoting mechanism in the imbalance between impulsive subcortical neural signals associated with immediate pleasurable outcomes and inhibitory signals mediated by a prefrontal reflective system. The resulting impairment in behavioral control represents a hallmark of alcohol use disorders (AUDs), a chronic relapsing disorder characterized by excessive alcohol consumption despite devastating consequences. This review aims to summarize available magnetic resonance imaging (MRI) evidence on reward-related decision-making alterations in AUDs, and to envision possible future research directions. We review functional MRI (fMRI) studies using tasks involving monetary rewards, as well as MRI studies relating decision-making parameters to neurostructural gray- or white-matter metrics. The available data suggest that excessive alcohol exposure affects neural signaling within brain networks underlying adaptive behavioral learning via the implementation of prediction errors. Namely, weaker ventromedial prefrontal cortex activity and altered connectivity between ventral striatum and dorsolateral prefrontal cortex likely underpin a shift from goal-directed to habitual actions which, in turn, might underpin compulsive alcohol consumption and relapsing episodes despite adverse consequences. Overall, these data highlight abnormal fronto-striatal connectivity as a candidate neurobiological marker of impaired choice in AUDs. Further studies are needed, however, to unveil its implications in the multiple facets of decision-making.

  13. Physical Performance Across the Adult Life Span: Correlates With Age and Physical Activity.

    Science.gov (United States)

    Hall, Katherine S; Cohen, Harvey J; Pieper, Carl F; Fillenbaum, Gerda G; Kraus, William E; Huffman, Kim M; Cornish, Melissa A; Shiloh, Andrew; Flynn, Christy; Sloane, Richard; Newby, L Kristin; Morey, Miriam C

    2017-04-01

    A number of large-scale population studies have provided valuable information about physical performance in aged individuals; however, there is little information about trajectories of function and associations with age across the adult life span. We developed a mobility-focused physical performance screener designed to be appropriate for the adult life span. The physical performance battery includes measures of mobility, strength, endurance, and balance. Physical activity (PA) was assessed with accelerometry. We examined age-related trends in physical performance and PA, and the relationship between physical performance and PA across the age range (30-90+), by decade, in 775 participants enrolled in the study 2012-2014. Physical performance was worse with increasing age decade. Although men performed better than women across all ages, the decrement by age group was similar between genders. Worsening physical performance was observed as early as the fifth decade for chair stands and balance and in the sixth decade for gait speed and aerobic endurance. The number and strength of significant associations between physical performance and PA increased with greater age: the greatest number of significant associations was seen in the 60-79 age groups, with fewer reported in the 30-59 and 80-90+ age groups. More PA was associated with better physical function. These results emphasize the importance of a life span approach to studies of function and aging. This work points to the need for a physical performance screener that spans across adulthood as a clinical tool for identifying functional decline. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Gait performance is not influenced by working memory when walking at a self-selected pace.

    Science.gov (United States)

    Grubaugh, Jordan; Rhea, Christopher K

    2014-02-01

    Gait performance exhibits patterns within the stride-to-stride variability that can be indexed using detrended fluctuation analysis (DFA). Previous work employing DFA has shown that gait patterns can be influenced by constraints, such as natural aging or disease, and they are informative regarding a person's functional ability. Many activities of daily living require concurrent performance in the cognitive and gait domains; specifically working memory is commonly engaged while walking, which is considered dual-tasking. It is unknown if taxing working memory while walking influences gait performance as assessed by DFA. This study used a dual-tasking paradigm to determine if performance decrements are observed in gait or working memory when performed concurrently. Healthy young participants (N = 16) performed a working memory task (automated operation span task) and a gait task (walking at a self-selected speed on a treadmill) in single- and dual-task conditions. A second dual-task condition (reading while walking) was included to control for visual attention, but also introduced a task that taxed working memory over the long term. All trials involving gait lasted at least 10 min. Performance in the working memory task was indexed using five dependent variables (absolute score, partial score, speed error, accuracy error, and math error), while gait performance was indexed by quantifying the mean, standard deviation, and DFA α of the stride interval time series. Two multivariate analyses of variance (one for gait and one for working memory) were used to examine performance in the single- and dual-task conditions. No differences were observed in any of the gait or working memory dependent variables as a function of task condition. The results suggest the locomotor system is adaptive enough to complete a working memory task without compromising gait performance when walking at a self-selected pace.

  15. Performance of

    Directory of Open Access Journals (Sweden)

    Naema A. Ali

    2015-09-01

    Full Text Available Soil collapse occurs when increased moisture causes chemical or physical bonds between the soil particles to weaken, which allows the structure of the soil to collapse. Collapsible soils are generally low-density, fine-grained combinations of clay and sand left by mudflows that have dried, leaving tiny air pockets. When the soil is dry, the cemented materials are strong enough to bond the sand particles together. When natural soil becomes wet, moisture alters the cementation structure and the soil’s strength is compromised, causing collapse or subsidence. Based on soil type and density, the potential for encountering collapsible soils throughout most of the project alignment is low. Conditions in arid and semi-arid climates like Borg El Arab, near Alexandria Egypt favor the formation of the most problematic collapsible soils. The behavior and performance of compacted sand replacement over treated collapsible soil by pre-wetting and compaction are investigated in the current study. Field investigation was performed in the form of plate loading tests conducted on compacted sand replacement over improved collapsible soil. Field plate load tests program was developed to explore the effect of compacted sand replacement thickness on collapsibility potential. Treated collapsible soil was replaced with imported cohesionless soil with variable thickness up to footing width. Results proved that the improvement of collapsible soils by sand/crushed stone replacement is possible to control/mitigate their risk potentials against sudden settlement when exposed to water. Replacement soil increases the rate and reduces the amount of footing settlement. For compacted collapsible soils, partial replacement by compacted sand/crushed stone layers decreases collapsibility potential risk. Results also, introduce the development of practical, economical and environmentally safe geochemical methods for collapsible soil stabilization and collapsible risk mitigation.

  16. Autopilot, Mind Wandering, and the Out of the Loop Performance Problem.

    Science.gov (United States)

    Gouraud, Jonas; Delorme, Arnaud; Berberian, Bruno

    2017-01-01

    To satisfy the increasing demand for safer critical systems, engineers have integrated higher levels of automation, such as glass cockpits in aircraft, power plants, and driverless cars. These guiding principles relegate the operator to a monitoring role, increasing risks for humans to lack system understanding. The out of the loop performance problem arises when operators suffer from complacency and vigilance decrement; consequently, when automation does not behave as expected, understanding the system or taking back manual control may be difficult. Close to the out of the loop problem, mind wandering points to the propensity of the human mind to think about matters unrelated to the task at hand. This article reviews the literature related to both mind wandering and the out of the loop performance problem as it relates to task automation. We highlight studies showing how these phenomena interact with each other while impacting human performance within highly automated systems. We analyze how this proximity is supported by effects observed in automated environment, such as decoupling, sensory attention, and cognitive comprehension decrease. We also show that this link could be useful for detecting out of the loop situations through mind wandering markers. Finally, we examine the limitations of the current knowledge because many questions remain open to characterize interactions between out of the loop, mind wandering, and automation.

  17. Coordination and collective performance: Cooperative goals boost interpersonal synchrony and task outcomes

    Directory of Open Access Journals (Sweden)

    Jamie S. Allsop

    2016-09-01

    Full Text Available Whether it be a rugby team or a rescue crew, ensuring peak group performance is a primary goal during collective activities. In reality however, groups often suffer from productivity losses that can lead to less than optimal outputs. Where researchers have focused on this problem, inefficiencies in the way team members coordinate their efforts has been identified as one potent source of productivity decrements. Here we set out to explore whether performance on a simple object movement task is shaped by the spontaneous emergence of interpersonally coordinated behavior. Forty-six pairs of participants were instructed to either compete or cooperate in order to empty a container of approximately 100 small plastic balls as quickly and accurately as possible. Each trial was recorded to video and a frame-differencing approach was employed to estimate between-person coordination. The results revealed that cooperative pairs coordinated to a greater extent than their competitive counterparts. Furthermore, coordination, as well as movement regularity were positively related to accuracy, an effect that was most prominent when the task was structured such that opportunities to coordinate were restricted. These findings are discussed with regard to contemporary theories of coordination and collective performance.

  18. Cardiac reactivity and preserved performance under stress: two sides of the same coin?

    Science.gov (United States)

    Pattyn, Nathalie; Mairesse, Olivier; Cortoos, Aisha; Morais, José; Soetens, Eric; Roelands, Bart; van den Nest, Annick; Kolinsky, Régine

    2014-07-01

    In the present experiment, cognitive control under stress was investigated using a real-life paradigm, namely an evaluation flight for military student pilots. The magnitude of cognitive interference on color-word, numerical and emotional Stroop paradigms was studied during a baseline recording and right before the test flight. Cardio-respiratory parameters were simultaneously assessed during rest and the performance of the Stroop tasks. Cognitive data suggested a different speed/accuracy trade-off under stress, and no modulation of the interference effect for color words or numerical stimuli. However, we observed a major increase in error rates for specific emotional stimuli related to the evaluation situation in the stress condition. The increase in cognitive interference from emotional stimuli, expressed as an increase in error rates, was correlated to the decreased cardiac reactivity to challenge in the stress situation. This relationship is discussed in the framework of Sanders' (1983) model of stress and performance. In terms of future research, this link warrants a fruitful lead to be followed for investigating the causal mechanism of performance decrements under the influence of stress. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Visual performance on detection tasks with double-targets of the same and different difficulty.

    Science.gov (United States)

    Chan, Alan H S; Courtney, Alan J; Ma, C W

    2002-10-20

    This paper reports a study of measurement of horizontal visual sensitivity limits for 16 subjects in single-target and double-targets detection tasks. Two phases of tests were conducted in the double-targets task; targets of the same difficulty were tested in phase one while targets of different difficulty were tested in phase two. The range of sensitivity for the double-targets test was found to be smaller than that for single-target in both the same and different target difficulty cases. The presence of another target was found to affect performance to a marked degree. Interference effect of the difficult target on detection of the easy one was greater than that of the easy one on the detection of the difficult one. Performance decrement was noted when correct percentage detection was plotted against eccentricity of target in both the single-target and double-targets tests. Nevertheless, the non-significant correlation found between the performance for the two tasks demonstrated that it was impossible to predict quantitatively ability for detection of double targets from the data for single targets. This indicated probable problems in generalizing data for single target visual lobes to those for multiple targets. Also lobe area values obtained from measurements using a single-target task cannot be applied in a mathematical model for situations with multiple occurrences of targets.

  20. Autopilot, Mind Wandering, and the Out of the Loop Performance Problem

    Directory of Open Access Journals (Sweden)

    Jonas Gouraud

    2017-10-01

    Full Text Available To satisfy the increasing demand for safer critical systems, engineers have integrated higher levels of automation, such as glass cockpits in aircraft, power plants, and driverless cars. These guiding principles relegate the operator to a monitoring role, increasing risks for humans to lack system understanding. The out of the loop performance problem arises when operators suffer from complacency and vigilance decrement; consequently, when automation does not behave as expected, understanding the system or taking back manual control may be difficult. Close to the out of the loop problem, mind wandering points to the propensity of the human mind to think about matters unrelated to the task at hand. This article reviews the literature related to both mind wandering and the out of the loop performance problem as it relates to task automation. We highlight studies showing how these phenomena interact with each other while impacting human performance within highly automated systems. We analyze how this proximity is supported by effects observed in automated environment, such as decoupling, sensory attention, and cognitive comprehension decrease. We also show that this link could be useful for detecting out of the loop situations through mind wandering markers. Finally, we examine the limitations of the current knowledge because many questions remain open to characterize interactions between out of the loop, mind wandering, and automation.

  1. Driving monotonous routes in a train simulator: the effect of task demand on driving performance and subjective experience.

    Science.gov (United States)

    Dunn, Naomi; Williamson, Ann

    2012-01-01

    Although monotony is widely recognised as being detrimental to performance, its occurrence and effects are not yet well understood. This is despite the fact that task-related characteristics, such as monotony and low task demand, have been shown to contribute to performance decrements over time. Participants completed one of two simulated train-driving scenarios. Both were highly monotonous and differed only in terms of the level of cognitive demand required (i.e. low demand or high demand). These results highlight the seriously detrimental effects of the combination of monotony and low task demands and clearly show that even a relatively minor increase in cognitive demand can mitigate adverse monotony-related effects on performance for extended periods of time. Monotony is an inherent characteristic of transport industries, including rail, aviation and road transport, which can have adverse impact on safety, reliability and efficiency. This study highlights possible strategies for mitigating these adverse effects. Practitioner Summary: This study provides evidence for the importance of cognitive demand in mitigating monotony-related effects on performance. The results have clear implications for the rapid onset of performance deterioration in low demand monotonous tasks and demonstrate that these detrimental performance effects can be overcome with simple solutions, such as making the task more cognitively engaging.

  2. Increased default-mode variability is related to reduced task-performance and is evident in adults with ADHD

    Directory of Open Access Journals (Sweden)

    Athanasia M. Mowinckel

    2017-01-01

    Full Text Available Insufficient suppression and connectivity of the default mode network (DMN is a potential mediator of cognitive dysfunctions across various disorders, including attention deficit/hyperactivity disorder (ADHD. However, it remains unclear if alterations in sustained DMN suppression, variability and connectivity during prolonged cognitive engagement are implicated in adult ADHD pathophysiology, and to which degree methylphenidate (MPH remediates any DMN abnormalities. This randomized, double-blinded, placebo-controlled, cross-over clinical trial of MPH (clinicaltrials.gov/ct2/show/NCT01831622 explored large-scale brain network dynamics in 20 adults with ADHD on and off MPH, compared to 27 healthy controls, while performing a reward based decision-making task. DMN task-related activation, variability, and connectivity were estimated and compared between groups and conditions using independent component analysis, dual regression, and Bayesian linear mixed models. The results show that the DMN exhibited more variable activation patterns in unmedicated patients compared to healthy controls. Group differences in functional connectivity both between and within functional networks were evident. Further, functional connectivity between and within attention and DMN networks was sensitive both to task performance and case-control status. MPH altered within-network connectivity of the DMN and visual networks, but not between-network connectivity or temporal variability. This study thus provides novel fMRI evidence of reduced sustained DMN suppression in adults with ADHD during value-based decision-making, a pattern that was not alleviated by MPH. We infer from multiple analytical approaches further support to the default mode interference hypothesis, in that higher DMN activation variability is evident in adult ADHD and associated with lower task performance.

  3. Simulated astigmatism impairs academic-related performance in children.

    Science.gov (United States)

    Narayanasamy, Sumithira; Vincent, Stephen J; Sampson, Geoff P; Wood, Joanne M

    2015-01-01

    Astigmatism is an important refractive condition in children. However, the functional impact of uncorrected astigmatism in this population is not well established, particularly with regard to academic performance. This study investigated the impact of simulated bilateral astigmatism on academic-related tasks before and after sustained near work in children. Twenty visually normal children (mean age: 10.8 ± 0.7 years; six males and 14 females) completed a range of standardised academic-related tests with and without 1.50 D of simulated bilateral astigmatism (with both academic-related tests and the visual condition administered in a randomised order). The simulated astigmatism was induced using a positive cylindrical lens while maintaining a plano spherical equivalent. Performance was assessed before and after 20 min of sustained near work, during two separate testing sessions. Academic-related measures included a standardised reading test (the Neale Analysis of Reading Ability), visual information processing tests (Coding and Symbol Search subtests from the Wechsler Intelligence Scale for Children) and a reading-related eye movement test (the Developmental Eye Movement test). Each participant was systematically assigned either with-the-rule (WTR, axis 180°) or against-the-rule (ATR, axis 90°) simulated astigmatism to evaluate the influence of axis orientation on any decrements in performance. Reading, visual information processing and reading-related eye movement performance were all significantly impaired by both simulated bilateral astigmatism (p  0.05). Simulated astigmatism led to a reduction of between 5% and 12% in performance across the academic-related outcome measures, but there was no significant effect of the axis (WTR or ATR) of astigmatism (p > 0.05). Simulated bilateral astigmatism impaired children's performance on a range of academic-related outcome measures irrespective of the orientation of the astigmatism. These findings have

  4. Defining the Physiological Factors that Contribute to Postflight Changes in Functional Performance

    Science.gov (United States)

    Bloomberg, J. J.; Arzeno, N.; Buxton, R.; Feiveson, A. H.; Kofman, I.; Lawrence, E.; Lee, S. M. C.; Mulavara, A. P.; Peters, B. T.; Platts, S. H.; hide

    2009-01-01

    Astronauts experience alterations in multiple physiological systems due to exposure to the microgravity conditions of space flight. These physiological changes include sensorimotor disturbances, cardiovascular deconditioning and loss of muscle mass and strength. These changes might affect the ability of crewmembers to perform critical mission tasks immediately after landing on lunar and Martian surfaces. To date, changes in functional performance have not been systematically studied or correlated with physiological changes. To understand how changes in physiological function impact functional performance an interdisciplinary pre/postflight testing regimen (Functional Task Test, FTT) has been developed that systematically evaluates both astronaut postflight functional performance and related physiological changes. The overall objective of the FTT is to identify the key underlying physiological factors that contribute to performance of functional tests that are representative of critical mission tasks. This study will identify which physiological systems contribute the most to impaired performance on each functional test. This will allow us to identify the physiological systems that play the largest role in decrement in functional performance. Using this information we can then design and implement countermeasures that specifically target the physiological systems most responsible for the altered functional performance associated with space flight. The functional test battery was designed to address high priority tasks identified by the Constellation program as critical for mission success. The set of functional tests making up the FTT include the: 1) Seat Egress and Walk Test, 2) Ladder Climb Test, 3) Recovery from Fall/Stand Test, 4) Rock Translation Test, 5) Jump Down Test, 6) Torque Generation Test, and 7) Construction Activity Board Test. Corresponding physiological measures include assessments of postural and gait control, dynamic visual acuity, fine motor

  5. Effects of Information Availability on Command-and-Control Decision Making: Performance, Trust, and Situation Awareness.

    Science.gov (United States)

    Marusich, Laura R; Bakdash, Jonathan Z; Onal, Emrah; Yu, Michael S; Schaffer, James; O'Donovan, John; Höllerer, Tobias; Buchler, Norbou; Gonzalez, Cleotilde

    2016-03-01

    We investigated how increases in task-relevant information affect human decision-making performance, situation awareness (SA), and trust in a simulated command-and-control (C2) environment. Increased information is often associated with an improvement of SA and decision-making performance in networked organizations. However, previous research suggests that increasing information without considering the task relevance and the presentation can impair performance. We used a simulated C2 task across two experiments. Experiment 1 varied the information volume provided to individual participants and measured the speed and accuracy of decision making for task performance. Experiment 2 varied information volume and information reliability provided to two participants acting in different roles and assessed decision-making performance, SA, and trust between the paired participants. In both experiments, increased task-relevant information volume did not improve task performance. In Experiment 2, increased task-relevant information volume reduced self-reported SA and trust, and incorrect source reliability information led to poorer task performance and SA. These results indicate that increasing the volume of information, even when it is accurate and task relevant, is not necessarily beneficial to decision-making performance. Moreover, it may even be detrimental to SA and trust among team members. Given the high volume of available and shared information and the safety-critical and time-sensitive nature of many decisions, these results have implications for training and system design in C2 domains. To avoid decrements to SA, interpersonal trust, and decision-making performance, information presentation within C2 systems must reflect human cognitive processing limits and capabilities. © 2016, Human Factors and Ergonomics Society.

  6. Reduced memory and attention performance in a population-based sample of young adults with a moderate lifetime use of cannabis, ecstasy and alcohol.

    Science.gov (United States)

    Indlekofer, F; Piechatzek, M; Daamen, M; Glasmacher, C; Lieb, R; Pfister, H; Tucha, O; Lange, K W; Wittchen, H U; Schütz, C G

    2009-07-01

    Regular use of illegal drugs is suspected to cause cognitive impairments. Two substances have received heightened attention: 3,4-methylenedioxymethamphetamine (MDMA or 'ecstasy') and delta-9-tetrahydrocannabinol (THC or 'cannabis'). Preclinical evidence, as well as human studies examining regular ecstasy consumers, indicated that ecstasy use may have negative effects on learning, verbal memory and complex attentional functions. Cannabis has also been linked to symptoms of inattention and deficits in learning and memory. Most of the published studies in this field of research recruited participants by means of newspaper advertisements or by using word-of-mouth strategies. Because participants were usually aware that their drug use was critical to the research design, this awareness may have caused selection bias or created expectation effects. Focussing on attention and memory, this study aimed to assess cognitive functioning in a community-based representative sample that was derived from a large-scale epidemiological study. Available data concerning drug use history allowed sampling of subjects with varying degrees of lifetime drug experiences. Cognitive functioning was examined in 284 young participants, between 22 and 34 years. In general, their lifetime drug experience was moderate. Participants completed a neuropsychological test battery, including measures for verbal learning, memory and various attentional functions. Linear regression analysis was performed to investigate the relationship between cognitive functioning and lifetime experience of drug use. Ecstasy and cannabis use were significantly related to poorer episodic memory function in a dose-related manner. For attentional measures, decrements of small effect sizes were found. Error measures in tonic and phasic alertness tasks, selective attention task and vigilance showed small but significant effects, suggesting a stronger tendency to experience lapses of attention. No indication for differences in

  7. The efiect of sevoflurane induction on the myocardial performance ...

    African Journals Online (AJOL)

    single numeric value and correlates well with conventional haemodynamic measures .... significant decrement of the IVCT (–3.37; p-value 0.0005). Isovolumic .... with invasive measurement of ventricular function in a porcine model. J Am Soc ...

  8. Jump-Down Performance Alterations after Space Flight

    Science.gov (United States)

    Reschke, M. F.; Kofman, I. S.; Cerisano, J. M.; Fisher, E. A.; Peters, B. T.; Miller, C. A.; Harm, D. L.; Bloomberg, J. J.

    2011-01-01

    INTRODUCTION: Successful jump performance requires functional coordination of visual, vestibular, and somatosensory systems, which are affected by prolonged exposure to microgravity. Astronauts returning from space flight exhibit impaired ability to coordinate effective landing strategies when jumping from a platform to the ground. This study compares jump strategies used by astronauts before and after flight, changes to those strategies within a test session, and recoveries in jump-down performance parameters across several postflight test sessions. These data were obtained as part of an ongoing interdisciplinary study (Functional Task Test, FTT) designed to evaluate both astronaut postflight functional performance and related physiological changes. METHODS: Seven astronauts from short-duration (Shuttle) and three from long-duration (International Space Station) flights performed 3 two-footed jumps from a platform 30 cm high onto a force plate that measured the ground reaction forces and center-of-pressure displacement from the landings. Neuromuscular activation data were collected from the medial gastrocnemius and anterior tibialis of both legs using surface electromyography electrodes. Two load cells in the platform measured the load exerted by each foot during the takeoff phase of the jump. Data were collected in 2 preflight sessions, on landing day (Shuttle only), and 1, 6, and 30 days after flight. RESULTS: Postural settling time was significantly increased on the first postflight test session and many of the astronauts tested were unable to maintain balance on their first jump landing but recovered by the third jump, showing a learning progression in which performance improvements could be attributed to adjustments in takeoff or landing strategy. Jump strategy changes were evident in reduced air time (time between takeoff and landing) and also in increased asymmetry in foot latencies on takeoff. CONCLUSIONS: The test results revealed significant decrements

  9. Infant speech-sound discrimination testing: effects of stimulus intensity and procedural model on measures of performance.

    Science.gov (United States)

    Nozza, R J

    1987-06-01

    Performance of infants in a speech-sound discrimination task (/ba/ vs /da/) was measured at three stimulus intensity levels (50, 60, and 70 dB SPL) using the operant head-turn procedure. The procedure was modified so that data could be treated as though from a single-interval (yes-no) procedure, as is commonly done, as well as if from a sustained attention (vigilance) task. Discrimination performance changed significantly with increase in intensity, suggesting caution in the interpretation of results from infant discrimination studies in which only single stimulus intensity levels within this range are used. The assumptions made about the underlying methodological model did not change the performance-intensity relationships. However, infants demonstrated response decrement, typical of vigilance tasks, which supports the notion that the head-turn procedure is represented best by the vigilance model. Analysis then was done according to a method designed for tasks with undefined observation intervals [C. S. Watson and T. L. Nichols, J. Acoust. Soc. Am. 59, 655-668 (1976)]. Results reveal that, while group data are reasonably well represented across levels of difficulty by the fixed-interval model, there is a variation in performance as a function of time following trial onset that could lead to underestimation of performance in some cases.

  10. Word Memory Test Performance Across Cognitive Domains, Psychiatric Presentations, and Mild Traumatic Brain Injury.

    Science.gov (United States)

    Rowland, Jared A; Miskey, Holly M; Brearly, Timothy W; Martindale, Sarah L; Shura, Robert D

    2017-05-01

    The current study addressed two aims: (i) determine how Word Memory Test (WMT) performance relates to test performance across numerous cognitive domains and (ii) evaluate how current psychiatric disorders or mild traumatic brain injury (mTBI) history affects performance on the WMT after excluding participants with poor symptom validity. Participants were 235 Iraq and Afghanistan-era veterans (Mage = 35.5) who completed a comprehensive neuropsychological battery. Participants were divided into two groups based on WMT performance (Pass = 193, Fail = 42). Tests were grouped into cognitive domains and an average z-score was calculated for each domain. Significant differences were found between those who passed and those who failed the WMT on the memory, attention, executive function, and motor output domain z-scores. WMT failure was associated with a larger performance decrement in the memory domain than the sensation or visuospatial-construction domains. Participants with a current psychiatric diagnosis or mTBI history were significantly more likely to fail the WMT, even after removing participants with poor symptom validity. Results suggest that the WMT is most appropriate for assessing validity in the domains of attention, executive function, motor output and memory, with little relationship to performance in domains of sensation or visuospatial-construction. Comprehensive cognitive batteries would benefit from inclusion of additional performance validity tests in these domains. Additionally, symptom validity did not explain higher rates of WMT failure in individuals with a current psychiatric diagnosis or mTBI history. Further research is needed to better understand how these conditions may affect WMT performance. Published by Oxford University Press 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  11. Assessing air medical crew real-time readiness to perform critical tasks.

    Science.gov (United States)

    Braude, Darren; Goldsmith, Timothy; Weiss, Steven J

    2011-01-01

    Air medical transport has had problems with its safety record, attributed in part to human error. Flight crew members (FCMs) must be able to focus on critical safety tasks in the context of a stressful environment. Flight crew members' cognitive readiness (CR) to perform their jobs may be affected by sleep deprivation, personal problems, high workload, and use of alcohol and drugs. The current study investigated the feasibility of using a computer-based cognitive task to assess FCMs' readiness to perform their job. The FCMs completed a short questionnaire to evaluate their physiologic and psychological state at the beginning and end of each shift. The FCMs then performed 3 minutes of a computer-based cognitive task called synthetic work environment (SYNWIN test battery). Task performance was compared with the questionnaire variables using correlation and regression analysis. Differences between the beginning and end of each shift were matched and compared using a paired Students t test. SYNWIN performance was significantly worse at the end of a shift compared with the beginning of the shift (p = 0.028) primarily because of decrement in the memory component. The SYNWIN composite scores were negatively correlated to degree of irritability felt by the participant, both before (r = -0.25) and after (r = -0.34) a shift and were significantly correlated with amount of sleep (0.22), rest (0.30), and life satisfaction (0.30). Performance by FCMs on a simple, rapid, computer-based psychological test correlates well with self-reported sleep, rest, life satisfaction, and irritability. Although further studies are warranted, these findings suggest that assessment of the performance of FCMs on a simple, rapid, computer-based, multitasking battery is feasible as an approach to determine their readiness to perform critical safety tasks through the SYNWIN task battery.

  12. Effects of Non-Driving Related Task Modalities on Takeover Performance in Highly Automated Driving.

    Science.gov (United States)

    Wandtner, Bernhard; Schömig, Nadja; Schmidt, Gerald

    2018-04-01

    Aim of the study was to evaluate the impact of different non-driving related tasks (NDR tasks) on takeover performance in highly automated driving. During highly automated driving, it is allowed to engage in NDR tasks temporarily. However, drivers must be able to take over control when reaching a system limit. There is evidence that the type of NDR task has an impact on takeover performance, but little is known about the specific task characteristics that account for performance decrements. Thirty participants drove in a simulator using a highly automated driving system. Each participant faced five critical takeover situations. Based on assumptions of Wickens's multiple resource theory, stimulus and response modalities of a prototypical NDR task were systematically manipulated. Additionally, in one experimental group, the task was locked out simultaneously with the takeover request. Task modalities had significant effects on several measures of takeover performance. A visual-manual texting task degraded performance the most, particularly when performed handheld. In contrast, takeover performance with an auditory-vocal task was comparable to a baseline without any task. Task lockout was associated with faster hands-on-wheel times but not altered brake response times. Results showed that NDR task modalities are relevant factors for takeover performance. An NDR task lockout was highly accepted by the drivers and showed moderate benefits for the first takeover reaction. Knowledge about the impact of NDR task characteristics is an enabler for adaptive takeover concepts. In addition, it might help regulators to make decisions on allowed NDR tasks during automated driving.

  13. Dip-Coating Process Engineering and Performance Optimization for Three-State Electrochromic Devices

    Science.gov (United States)

    Wu, Lu; Yang, Dejiang; Fei, Lixun; Huang, Yue; Wu, Fang; Sun, Yiling; Shi, Jiayuan; Xiang, Yong

    2017-06-01

    Titanium dioxide (TiO2) nanoparticles were modified onto fluorine-doped tin oxide (FTO) via dip-coating technique with different nanoparticle sizes, lifting speeds, precursor concentrations, and dipping numbers. Electrodeposition-based electrochromic device with reversible three-state optical transformation (transparent, mirror, and black) was fabricated subsequently by sandwiching a suitable amount of gel electrolyte between modified FTO electrode and flat FTO electrode. Correlation between dip-coating process engineering, morphological features of TiO2 thin films, i.e., thickness and roughness, as well as performance of electrochromic devices, i.e., optical contrast, switching time, and cycling stability, were investigated. The modified device exhibits high optical contrast of 57%, the short coloration/bleaching switching time of 6 and 20 s, and excellent cycling stability after 1500 cycles of only 27% decrement rate by adjusting dip-coating processes engineering. The results in this study will provide valuable guidance for rational design of the electrochromic device with satisfactory performance.

  14. Influence of carbohydrate supplementation on skill performance during a soccer match simulation.

    Science.gov (United States)

    Russell, Mark; Benton, David; Kingsley, Michael

    2012-07-01

    This study investigated the influence of carbohydrate supplementation on skill performance throughout exercise that replicates soccer match-play. Experimentation was conducted in a randomised, double-blind and cross-over study design. After familiarization, 15 professional academy soccer players completed a soccer match simulation incorporating passing, dribbling and shooting on two separate occasions. Participants received a 6% carbohydrate-electrolyte solution (CHO) or electrolyte solution (PL). Precision, success rate, ball speed and an overall index (speed-precision-success; SPS) were determined for all skills. Blood samples were taken at rest, immediately before exercise, every 15 min during exercise (first half: 15, 30 and 45 min; second half: 60, 75 and 90 min), and 10 min into the half time (half-time). Carbohydrate supplementation influenced shooting (time×treatment interaction: pinteraction: pCarbohydrate supplementation attenuated decrements in shooting performance during simulated soccer match-play; however, further research is warranted to optimise carbohydrate supplementation regimes for high-intensity intermittent sports. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  15. Functional asymmetries in early learning during right, left, and bimanual performance in right-handed subjects.

    Science.gov (United States)

    Aznárez-Sanado, Maite; Fernández-Seara, Maria A; Loayza, Francis R; Pastor, Maria A

    2013-03-01

    To elucidate differences in activity and connectivity during early learning due to the performing hand. Twenty right-handed subjects were recruited. The neural correlates of explicit visuospatial learning executed with the right, the left hand, and bimanually were investigated using functional magnetic resonance imaging. Connectivity analyses were carried out using the psychophysiological interactions model, considering right and left anterior putamen as index regions. A common neural network was found for the three tasks during learning. Main activity increases were located in posterior cingulate cortex, supplementary motor area, parietal cortex, anterior putamen, and cerebellum (IV-V), whereas activity decrements were observed in prefrontal regions. However, the left hand task showed a greater recruitment of left hippocampal areas when compared with the other tasks. In addition, enhanced connectivity between the right anterior putamen and motor cortical and cerebellar regions was found for the left hand when compared with the right hand task. An additional recruitment of brain regions and increased striato-cortical and striato-cerebellar functional connections is needed when early learning is performed with the nondominant hand. In addition, access to brain resources during learning may be directed by the dominant hand in the bimanual task. Copyright © 2012 Wiley Periodicals, Inc.

  16. Sustained attention performance during sleep deprivation associates with instability in behavior and physiologic measures at baseline.

    Science.gov (United States)

    Chua, Eric Chern-Pin; Yeo, Sing-Chen; Lee, Ivan Tian-Guang; Tan, Luuan-Chin; Lau, Pauline; Cai, Shiwei; Zhang, Xiaodong; Puvanendran, Kathiravelu; Gooley, Joshua J

    2014-01-01

    To identify baseline behavioral and physiologic markers that associate with individual differences in sustained attention during sleep deprivation. In a retrospective study, ocular, electrocardiogram, and electroencephalogram (EEG) measures were compared in subjects who were characterized as resilient (n = 15) or vulnerable (n = 15) to the effects of total sleep deprivation on sustained attention. Chronobiology and Sleep Laboratory, Duke-NUS Graduate Medical School Singapore. Healthy volunteers aged 22-32 years from the general population. Subjects were kept awake for at least 26 hours under constant environmental conditions. Every 2 hours, sustained attention was assessed using a 10-minute psychomotor vigilance task (PVT). During baseline sleep and recovery sleep, EEG slow wave activity was similar in resilient versus vulnerable subjects, suggesting that individual differences in vulnerability to sleep loss were not related to differences in homeostatic sleep regulation. Rather, irrespective of time elapsed since wake, subjects who were vulnerable to sleep deprivation exhibited slower and more variable PVT response times, lower and more variable heart rate, and higher and more variable EEG spectral power in the theta frequency band (6.0-7.5 Hz). Performance decrements in sustained attention during sleep deprivation associate with instability in behavioral and physiologic measures at baseline. Small individual differences in sustained attention that are present at baseline are amplified during prolonged wakefulness, thus contributing to large between-subjects differences in performance and sleepiness.

  17. Differentiating anxiety forms and their role in academic performance from primary to secondary school.

    Science.gov (United States)

    Carey, Emma; Devine, Amy; Hill, Francesca; Szűcs, Dénes

    2017-01-01

    Individuals with high levels of mathematics anxiety are more likely to have other forms of anxiety, such as general anxiety and test anxiety, and tend to have some math performance decrement compared to those with low math anxiety. However, it is unclear how the anxiety forms cluster in individuals, or how the presence of other anxiety forms influences the relationship between math anxiety and math performance. We measured math anxiety, test anxiety, general anxiety and mathematics and reading performance in 1720 UK students (year 4, aged 8-9, and years 7 and 8, aged 11-13). We conducted latent profile analysis of students' anxiety scores in order to examine the developmental change in anxiety profiles, the demographics of each anxiety profile and the relationship between profiles and academic performance. Anxiety profiles appeared to change in specificity between the two age groups studied. Only in the older students did clusters emerge with specifically elevated general anxiety or academic anxiety (test and math anxiety). Our findings suggest that boys are slightly more likely than girls to have elevated academic anxieties relative to their general anxiety. Year 7/8 students with specifically academic anxiety show lower academic performance than those who also have elevated general anxiety. There may be a developmental change in the specificity of anxiety and gender seems to play a strong role in determining one's anxiety profile. The anxiety profiles present in our year 7/8 sample, and their relationships with math performance, suggest a bidirectional relationship between math anxiety and math performance.

  18. The effect of the Ramadan fast on physical performance and dietary habits in adolescent soccer players.

    Science.gov (United States)

    Meckel, Yoav; Ismaeel, Aobeida; Eliakim, Alon

    2008-04-01

    The purpose of this study was to examine the effect of the Ramadan fast on performance capacities, dietary habits, and the daily behavioral patterns in adolescent (14-16-year-old) soccer players. Nineteen male players performed a series of fitness tests before and at the end of Ramadan fast. Caloric intake, physical activity pattern and sleep habits were evaluated during the week before the Ramadan fast and during the last week of the Ramadan fast. The fast resulted in a significant reduction in aerobic capacity [3,000 m run time (mean +/- SD): 812.8 +/- 73.3 s vs. 819.9 +/- 73.4 s, P performance decrement: 9.0 +/- 1.5% vs. 9.5 +/- 1.7%, P performance (44.8 +/- 4.5 cm vs. 44.0 +/- 4.5 cm, P performance (7.38 +/- 0.25 s vs. 7.40 +/- 0.26 s, P = 0.20) or agility (4 x 10 m shuttle run time: 9.53 +/- 0.35 s vs. 9.55 +/- 0.37 s, P = 0.26). Daily intense physical activity was significantly reduced during Ramadan (6.4 +/- 0.2 h/week vs. 4.5 +/- 0.1 h/week, P sleeping hours (8.6 +/- 0.7 h/day vs. 8.6 +/- 0.5 h/day, P = 0.80) between Ramadan and a regular month. The results indicate that Ramadan fasting can lead to a significant decrease in athletic performance capacities. The decrease in performance does not necessarily relate to changes in caloric intake and sleeping hours during the fast.

  19. Differentiating anxiety forms and their role in academic performance from primary to secondary school.

    Directory of Open Access Journals (Sweden)

    Emma Carey

    Full Text Available Individuals with high levels of mathematics anxiety are more likely to have other forms of anxiety, such as general anxiety and test anxiety, and tend to have some math performance decrement compared to those with low math anxiety. However, it is unclear how the anxiety forms cluster in individuals, or how the presence of other anxiety forms influences the relationship between math anxiety and math performance.We measured math anxiety, test anxiety, general anxiety and mathematics and reading performance in 1720 UK students (year 4, aged 8-9, and years 7 and 8, aged 11-13. We conducted latent profile analysis of students' anxiety scores in order to examine the developmental change in anxiety profiles, the demographics of each anxiety profile and the relationship between profiles and academic performance.Anxiety profiles appeared to change in specificity between the two age groups studied. Only in the older students did clusters emerge with specifically elevated general anxiety or academic anxiety (test and math anxiety. Our findings suggest that boys are slightly more likely than girls to have elevated academic anxieties relative to their general anxiety. Year 7/8 students with specifically academic anxiety show lower academic performance than those who also have elevated general anxiety.There may be a developmental change in the specificity of anxiety and gender seems to play a strong role in determining one's anxiety profile. The anxiety profiles present in our year 7/8 sample, and their relationships with math performance, suggest a bidirectional relationship between math anxiety and math performance.

  20. Beta-hydroxy-beta-methylbutyrate (HMB) ameliorates age-related deficits in water maze performance, especially in male rats.

    Science.gov (United States)

    Kougias, Daniel G; Hankosky, Emily R; Gulley, Joshua M; Juraska, Janice M

    2017-03-01

    Beta-hydroxy-beta-methylbutyrate (HMB) is commonly supplemented to maintain muscle in elderly and clinical populations and has potential as a nootropic. Previously, we have shown that in both male and female rats, long-term HMB supplementation prevents age-related dendritic shrinkage within the medial prefrontal cortex (mPFC) and improves cognitive flexibility and working memory performance that are both age- and sex-specific. In this study, we further explore the cognitive effects by assessing visuospatial learning and memory with the Morris water maze. Female rats were ovariectomized at 11months of age to model human menopause. At 12months of age, male and female rats received relatively short- or long-term (1- or 7-month) dietary HMB (450mg/kg/dose) supplementation twice a day prior to testing. Spatial reference learning and memory was assessed across four days in the water maze with four trials daily and a probe trial on the last day. Consistent with previous work, there were age-related deficits in water maze performance in both sexes. However, these deficits were ameliorated in HMB-treated males during training and in both sexes during probe trial performance. Thus, HMB supplementation prevented the age-related decrement in water maze performance, especially in male rats. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Characteristics of radiation-induced performance changes in bar-press avoidance with and without a preshock warning cue

    International Nuclear Information System (INIS)

    Burghardt, W.F. Jr.; Hunt, W.A.

    1989-01-01

    Rats were trained to perform one of three tasks in which responses on a lever delayed the onset of footshock for 20 sec. One task provided a warning tone beginning 15 sec after the last response on the lever and lasting for 5 sec just prior to the presentation of a shock (fixed-interval signalled avoidance), while a second task provided no external cues (unsignalled avoidance). The third task was similar to the fixed-interval signalled avoidance task, except that the warning tone preceding shock began at varying intervals after the last response on the lever (variable-interval signalled avoidance). Animals trained on the signalled avoidance paradigms received fewer shocks than those on the unsignalled avoidance paradigm. After 10 krads of gamma radiation, animals performing on either task with cues were less able to avoid shock, although they recovered somewhat over a 90-min period. The animals not provided cues also experienced more shocks during the first 10 min after irradiation but were relatively less affected in performing the task. Response rates on the bar and the patterns of responding on these tasks were not significantly different after irradiation, except that animals responded after the onset of shock more often after irradiation than before. These results suggest that rats will continue to effectively use task related cues after irradiation, but that the relative degree of behavioral decrement may depend on the initial level of performance or possibly the complexity of the task

  2. Effect of load carriage and natural terrain conditions on cognitive performance in desert environments.

    Science.gov (United States)

    Bhattacharyya, Debojyoti; Pal, Madhusudan; Chatterjee, Tirthankar; Majumdar, Dhurjati

    2017-10-01

    Correct decision making is a critical component of cognitive performance of a soldier, which may be influenced by the load carriage and terrain conditions during their deployment in desert environment. The present study was aimed to investigate the effects of loads and terrain conditions on the cognitive performance in a group of twelve healthy heat acclimatized infantry soldiers under natural desert environment. The soldiers participated in a 10min walking trial during carrying no load and also carrying 10.7, 21.4 and 30kg at two terrain conditions viz., sandy and hard. We studied attention, memory and executive function, which are having immense functional importance in military operations. Standardized cognitive test battery was applied to the participants after carrying each magnitude of load at each terrain. Baseline cognitive performance was recorded on a separate day and was compared with the performances recorded after the load carriage trials. An attempt was made to reveal the relationship between physiological workload (relative workload) and cognitive performance at the point of completion of load carriage trials. Load, terrains and load×terrain interaction did not produce any significant effect (p>0.05) on the cognitive performance. Attention and relative workload were found significantly correlated at hard terrain under no load, 21.4kg and 30kg. Significant correlation was found between executive function and relative workload at hard terrain under no load. Carrying upto 30kg load for 10min at 3.5-4kmph walking speed resulted in improvement in attention at sandy terrain, decrement in memory at both sandy and hard terrains and improvement in executive function at sandy terrain. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Impact of monetary incentives on cognitive performance and error monitoring following sleep deprivation.

    Science.gov (United States)

    Hsieh, Shulan; Li, Tzu-Hsien; Tsai, Ling-Ling

    2010-04-01

    To examine whether monetary incentives attenuate the negative effects of sleep deprivation on cognitive performance in a flanker task that requires higher-level cognitive-control processes, including error monitoring. Twenty-four healthy adults aged 18 to 23 years were randomly divided into 2 subject groups: one received and the other did not receive monetary incentives for performance accuracy. Both subject groups performed a flanker task and underwent electroencephalographic recordings for event-related brain potentials after normal sleep and after 1 night of total sleep deprivation in a within-subject, counterbalanced, repeated-measures study design. Monetary incentives significantly enhanced the response accuracy and reaction time variability under both normal sleep and sleep-deprived conditions, and they reduced the effects of sleep deprivation on the subjective effort level, the amplitude of the error-related negativity (an error-related event-related potential component), and the latency of the P300 (an event-related potential variable related to attention processes). However, monetary incentives could not attenuate the effects of sleep deprivation on any measures of behavior performance, such as the response accuracy, reaction time variability, or posterror accuracy adjustments; nor could they reduce the effects of sleep deprivation on the amplitude of the Pe, another error-related event-related potential component. This study shows that motivation incentives selectively reduce the effects of total sleep deprivation on some brain activities, but they cannot attenuate the effects of sleep deprivation on performance decrements in tasks that require high-level cognitive-control processes. Thus, monetary incentives and sleep deprivation may act through both common and different mechanisms to affect cognitive performance.

  4. Team performance in networked supervisory control of unmanned air vehicles: effects of automation, working memory, and communication content.

    Science.gov (United States)

    McKendrick, Ryan; Shaw, Tyler; de Visser, Ewart; Saqer, Haneen; Kidwell, Brian; Parasuraman, Raja

    2014-05-01

    Assess team performance within a net-worked supervisory control setting while manipulating automated decision aids and monitoring team communication and working memory ability. Networked systems such as multi-unmanned air vehicle (UAV) supervision have complex properties that make prediction of human-system performance difficult. Automated decision aid can provide valuable information to operators, individual abilities can limit or facilitate team performance, and team communication patterns can alter how effectively individuals work together. We hypothesized that reliable automation, higher working memory capacity, and increased communication rates of task-relevant information would offset performance decrements attributed to high task load. Two-person teams performed a simulated air defense task with two levels of task load and three levels of automated aid reliability. Teams communicated and received decision aid messages via chat window text messages. Task Load x Automation effects were significant across all performance measures. Reliable automation limited the decline in team performance with increasing task load. Average team spatial working memory was a stronger predictor than other measures of team working memory. Frequency of team rapport and enemy location communications positively related to team performance, and word count was negatively related to team performance. Reliable decision aiding mitigated team performance decline during increased task load during multi-UAV supervisory control. Team spatial working memory, communication of spatial information, and team rapport predicted team success. An automated decision aid can improve team performance under high task load. Assessment of spatial working memory and the communication of task-relevant information can help in operator and team selection in supervisory control systems.

  5. Stereotype threat in classroom settings: the interactive effect of domain identification, task difficulty and stereotype threat on female students' maths performance.

    Science.gov (United States)

    Keller, Johannes

    2007-06-01

    Stereotype threat research revealed that negative stereotypes can disrupt the performance of persons targeted by such stereotypes. This paper contributes to stereotype threat research by providing evidence that domain identification and the difficulty level of test items moderate stereotype threat effects on female students' maths performance. The study was designed to test theoretical ideas derived from stereotype threat theory and assumptions outlined in the Yerkes-Dodson law proposing a nonlinear relationship between arousal, task difficulty and performance. Participants were 108 high school students attending secondary schools. Participants worked on a test comprising maths problems of different difficulty levels. Half of the participants learned that the test had been shown to produce gender differences (stereotype threat). The other half learned that the test had been shown not to produce gender differences (no threat). The degree to which participants identify with the domain of maths was included as a quasi-experimental factor. Maths-identified female students showed performance decrements under conditions of stereotype threat. Moreover, the stereotype threat manipulation had different effects on low and high domain identifiers' performance depending on test item difficulty. On difficult items, low identifiers showed higher performance under threat (vs. no threat) whereas the reverse was true in high identifiers. This interaction effect did not emerge on easy items. Domain identification and test item difficulty are two important factors that need to be considered in the attempt to understand the impact of stereotype threat on performance.

  6. The influence of age and mild cognitive impairment on associative memory performance and underlying brain networks.

    Science.gov (United States)

    Oedekoven, Christiane S H; Jansen, Andreas; Keidel, James L; Kircher, Tilo; Leube, Dirk

    2015-12-01

    Associative memory is essential to everyday activities, such as the binding of faces and corresponding names to form single bits of information. However, this ability often becomes impaired with increasing age. The most important neural substrate of associative memory is the hippocampus, a structure crucially implicated in the pathogenesis of Alzheimer's disease (AD). The main aim of this study was to compare neural correlates of associative memory in healthy aging and mild cognitive impairment (MCI), an at-risk state for AD. We used fMRI to investigate differences in brain activation and connectivity between young controls (n = 20), elderly controls (n = 32) and MCI patients (n = 21) during associative memory retrieval. We observed lower hippocampal activation in MCI patients than control groups during a face-name recognition task, and the magnitude of this decrement was correlated with lower associative memory performance. Further, increased activation in precentral regions in all older adults indicated a stronger involvement of the task positive network (TPN) with age. Finally, functional connectivity analysis revealed a stronger link of hippocampal and striatal components in older adults in comparison to young controls, regardless of memory impairment. In elderly controls, this went hand-in-hand with a stronger activation of striatal areas. Increased TPN activation may be linked to greater reliance on cognitive control in both older groups, while increased functional connectivity between the hippocampus and the striatum may suggest dedifferentiation, especially in elderly controls.

  7. Testing the count rate performance of the scintillation camera by exponential attenuation: Decaying source; Multiple filters

    International Nuclear Information System (INIS)

    Adams, R.; Mena, I.

    1988-01-01

    An algorithm and two fortrAN programs have been developed to evaluate the count rate performance of scintillation cameras from count rates reduced exponentially, either by a decaying source or by filtration. The first method is used with short-lived radionuclides such as 191 /sup m/Ir or 191 /sup m/Au. The second implements a National Electrical Manufacturers' Association (NEMA) protocol in which the count rate from a source of 191 /sup m/Tc is attenuated by a varying number of copper filters stacked over it. The count rate at each data point is corrected for deadtime loss after assigning an arbitrary deadtime (tau). A second-order polynomial equation is fitted to the logarithms of net count rate values: ln(R) = A+BT+CT 2 where R is the net corrected count rate (cps), and T is the elapsed time (or the filter thickness in the NEMA method). Depending on C, tau is incremented or decremented iteratively, and the count rate corrections and curve fittings are repeated until C approaches zero, indicating a correct value of the deadtime (tau). The program then plots the measured count rate versus the corrected count rate values

  8. The assessment of chronic health conditions on work performance, absence, and total economic impact for employers.

    Science.gov (United States)

    Collins, James J; Baase, Catherine M; Sharda, Claire E; Ozminkowski, Ronald J; Nicholson, Sean; Billotti, Gary M; Turpin, Robin S; Olson, Michael; Berger, Marc L

    2005-06-01

    The objective of this study was to determine the prevalence and estimate total costs for chronic health conditions in the U.S. workforce for the Dow Chemical Company (Dow). Using the Stanford Presenteeism Scale, information was collected from workers at five locations on work impairment and absenteeism based on self-reported "primary" chronic health conditions. Survey data were merged with employee demographics, medical and pharmaceutical claims, smoking status, biometric health risk factors, payroll records, and job type. Almost 65% of respondents reported having one or more of the surveyed chronic conditions. The most common were allergies, arthritis/joint pain or stiffness, and back or neck disorders. The associated absenteeism by chronic condition ranged from 0.9 to 5.9 hours in a 4-week period, and on-the-job work impairment ranged from a 17.8% to 36.4% decrement in ability to function at work. The presence of a chronic condition was the most important determinant of the reported levels of work impairment and absence after adjusting for other factors (P < 0.000). The total cost of chronic conditions was estimated to be 10.7% of the total labor costs for Dow in the United States; 6.8% was attributable to work impairment alone. For all chronic conditions studied, the cost associated with performance based work loss or "presenteeism" greatly exceeded the combined costs of absenteeism and medical treatment combined.

  9. Influence of tow duration on catch performance of trawl survey in the Mediterranean Sea.

    Directory of Open Access Journals (Sweden)

    Antonello Sala

    Full Text Available The aim of this study was to assess the effect of tow duration on catch per unit of swept area (CPUE, trawl catch performance, and the proportion of the species caught in a trawl survey. Longer tows are expected to have a greater probability of catching species. An average of 26 species were caught in the first 30 minutes, whereas only about one additional species was caught in the next 30 minutes in longer tows. The shorter tows involved a decrement in catch weight for 11 of the 12 target species sampled, demonstrating that tow duration did affect catch per unit of swept area CPUE. The shorter tows were associated with a significant reduction of the overall CPUE in terms of weight of the main target species and of the total catch (circa 60%. The same strong reduction of around 70% was found in particular for European hake (Merluccius merluccius and surmullet (Mullus spp and 50% for Nephrops (Nephrops norvegicus. The shorter tows were less efficient in catching large-sized hake, surmullet, Nephrops, Atlantic horse mackerel (Trachurus trachurus, and poor cod (Trisopterus minutus, even though the difference was significant only for Nephrops. Regardless of the p-value statistic, these findings suggest that the continuity of survey time series would be severely impaired by changing tow duration. Further work is required to explore a way to reduce tow duration without reducing CPUE.

  10. Experimental investigation on the thermal performance of a closed oscillating heat pipe in thermal management

    Science.gov (United States)

    Rao, Zhonghao; Wang, Qingchao; Zhao, Jiateng; Huang, Congliang

    2017-10-01

    To investigate the thermal performance of the closed oscillating heat pipe (OHP) as a passive heat transfer device in thermal management system, the gravitation force, surface tension, cooling section position and inclination angle were discussed with applied heating power ranging from 5 to 65 W. The deionized water was chosen as the working fluid and liquid-filling ratio was 50 ± 5%. The operation of the OHP mainly depends on the phase change of the working fluid. The working fluid within the OHP was constantly evaporated and cooled. The results show that the movement of the working fluid was similar to the forced damped mechanical vibration, it has to overcome the capillary resistance force and the stable oscillation should be that the OHP could successful startup. The oscillation frequency slowed and oscillation amplitude decreased when the inclination angle of the OHP increased. However, the thermal resistance increased. With the increment of the heating power, the average temperature of the evaporation and condensation section would be close. If the heating power was further increased, dry-out phenomenon within the OHP would appeared. With the decrement of the L, the start-up heating power also decreased and stable oscillation would be formed.

  11. Precooling leg muscle improves intermittent sprint exercise performance in hot, humid conditions.

    Science.gov (United States)

    Castle, Paul C; Macdonald, Adam L; Philp, Andrew; Webborn, Anthony; Watt, Peter W; Maxwell, Neil S

    2006-04-01

    We used three techniques of precooling to test the hypothesis that heat strain would be alleviated, muscle temperature (Tmu) would be reduced, and as a result there would be delayed decrements in peak power output (PPO) during exercise in hot, humid conditions. Twelve male team-sport players completed four cycling intermittent sprint protocols (CISP). Each CISP consisted of twenty 2-min periods, each including 10 s of passive rest, 5 s of maximal sprint against a resistance of 7.5% body mass, and 105 s of active recovery. The CISP, preceded by 20 min of no cooling (Control), precooling via an ice vest (Vest), cold water immersion (Water), and ice packs covering the upper legs (Packs), was performed in hot, humid conditions (mean +/- SE; 33.7 +/- 0.3 degrees C, 51.6 +/- 2.2% relative humidity) in a randomized order. The rate of heat strain increase during the CISP was faster in Control than Water and Packs (P body or whole body cooling.

  12. In-situ Elevated Temperature Mechanical Performance of MWCNT/epoxy Nanocomposite

    Directory of Open Access Journals (Sweden)

    Bhanu Pratap Singh

    2017-03-01

    Full Text Available The present investigation has been focused on the effects of multi-walled carbon nanotube (MWCNT addition on the mechanical performance of epoxy under different in-service elevated temperature environments. Room temperature flexural test results revealed that addition of 0.1 wt. % MWCNT into epoxy resin resulted in modulus and strength enhancement of 21 % and 9 % respectively. With increase in service temperature, significant decrement in both modulus and strength was noticed for both materials (neat epoxy and MWCNT/epoxy nanocomposite, but the rate of degradation was found to be quite drastic for the nanocomposite. At 90 °C temperature, the CNT/epoxy nanocomposite exhibited inferior modulus and strength, which are 41 % and 59 % lower than neat epoxy respectively. The variation trend in elastic modulus with temperature obtained from both flexural testing and DMA for both these materials was also analyzed. It was found that addition of 0.1 % CNT in the epoxy reduced the glass transition temperature by about 16°C.

  13. Chronic repetitive reaching and grasping results in decreased motor performance and widespread tissue responses in a rat model of MSD.

    Science.gov (United States)

    Barbe, Mary F; Barr, Ann E; Gorzelany, Irene; Amin, Mamta; Gaughan, John P; Safadi, Fayez F

    2003-01-01

    This study investigated changes in motor skills and tissues of the upper extremity (UE) with regard to injury and inflammatory reactions resulting from performance of a voluntary forelimb repetitive reaching and grasping task in rats. Rats reached for food at a rate of 4 reaches/min, 2 h/day, and 3 days/week for up to 8 weeks during which reach rate, task duration and movement strategies were observed. UE tissues were collected bilaterally at weekly time points of 3-8 weeks and examined for morphological changes. Serum was tested for levels of interleukin-1alpha (IL-1) protein. The macrophage-specific antibody, ED1, was used to identify infiltrating macrophages and the ED2 antibody was used to identify resident macrophages. Rats were unable to maintain baseline reach rate in weeks 5 and 6 of task performance. Alternative patterns of movement emerged. Fraying of tendon fibrils was observed after 6 weeks in the mid-forelimb. After 4 weeks, a general elevation of ED1-IR macrophages were seen in all tissues examined bilaterally including the contralateral, uninvolved forelimb and hindlimbs. Significantly more resident macrophages were seen at 6 and 8 weeks in the reach limb. At 8 weeks, serum levels of IL-1alpha increased significantly above week 0. Our results demonstrate that performance of repetitive tasks elicits motor decrements, signs of injury and a cellular and tissue responses associated with inflammation.

  14. Chronic sleep curtailment, even without extended (>16-h) wakefulness, degrades human vigilance performance.

    Science.gov (United States)

    McHill, Andrew W; Hull, Joseph T; Wang, Wei; Czeisler, Charles A; Klerman, Elizabeth B

    2018-05-21

    Millions of individuals routinely remain awake for more than 18 h daily, which causes performance decrements. It is unknown if these functional impairments are the result of that extended wakefulness or from the associated shortened sleep durations. We therefore examined changes in objective reaction time performance and subjective alertness in a 32-d inpatient protocol in which participants were scheduled to wakefulness durations below 16 h while on a 20-h "day," with randomization into standard sleep:wake ratio (1:2) or chronic sleep restriction (CSR) ratio (1:3.3) conditions. This protocol allowed determination of the contribution of sleep deficiency independent of extended wakefulness, since individual episodes of wakefulness in the CSR condition were only 15.33 h in duration (less than the usual 16 h of wakefulness in a 24-h day) and sleep episodes were 4.67 h in duration each cycle. We found that chronic short sleep duration, even without extended wakefulness, doubled neurobehavioral reaction time performance and increased lapses of attention fivefold, yet did not uniformly decrease self-reported alertness. Further, these impairments in neurobehavioral performance were worsened during the circadian night and were not recovered during the circadian day, indicating that the deleterious effect from the homeostatic buildup of CSR is expressed even during the circadian promotion of daytime arousal. These findings reveal a fundamental aspect of human biology: Chronic insufficient sleep duration equivalent to 5.6 h of sleep opportunity per 24 h impairs neurobehavioral performance and self-assessment of alertness, even without extended wakefulness.

  15. Performance Management or Performance Based Management?

    OpenAIRE

    Cristina PROTOPOPESCU

    2013-01-01

    In this paper we present some considerations about performance and performance management. Starting with the challenge of defining the performance concept, we intend to establish if „performance management” can be a new management system or it is just a sophisticated term for a HR strategy in order to improve the performance of teams and individuals. We also try to discuss the conection between performance management and management by objectives. Whether or not it is exageratted to talk about...

  16. Age-associated declines in muscle mass, strength, power, and physical performance: impact on fear of falling and quality of life.

    Science.gov (United States)

    Trombetti, A; Reid, K F; Hars, M; Herrmann, F R; Pasha, E; Phillips, E M; Fielding, R A

    2016-02-01

    This 3-year longitudinal study among older adults showed that declining muscle mass, strength, power, and physical performance are independent contributing factors to increased fear of falling, while declines of muscle mass and physical performance contribute to deterioration of quality of life. Our findings reinforce the importance of preserving muscle health with advancing age. The age-associated loss of skeletal muscle quantity and function are critical determinants of independent physical functioning in later life. Longitudinal studies investigating how decrements in muscle components of sarcopenia impact fear of falling (FoF) and quality of life (QoL) in older adults are lacking. Twenty-six healthy older subjects (age, 74.1 ± 3.7; Short Physical Performance Battery (SPPB) score ≥10) and 22 mobility-limited older subjects (age, 77.2 ± 4.4; SPPB score ≤9) underwent evaluations of lower extremity muscle size and composition by computed tomography, strength and power, and physical performance at baseline and after 3-year follow-up. The Falls Efficacy Scale (FES) and Short Form-36 questionnaire (SF-36) were also administered at both timepoints to assess FoF and QoL, respectively. At 3-year follow-up, muscle cross-sectional area (CSA) (p < 0.013) and power decreased (p < 0.001), while intermuscular fat infiltration increased (p < 0.001). These decrements were accompanied with a longer time to complete 400 m by 22 ± 46 s (p < 0.002). Using linear mixed-effects regression models, declines of muscle CSA, strength and power, and SPPB score were associated with increased FES score (p < 0.05 for each model). Reduced physical component summary score of SF-36 over follow-up was independently associated with decreased SPPB score (p < 0.020), muscle CSA (p < 0.046), and increased 400 m walk time (p < 0.003). In older adults with and without mobility limitations, declining muscle mass, strength, power, and physical

  17. Aerial Rotation Effects on Vertical Jump Performance Among Highly Skilled Collegiate Soccer Players.

    Science.gov (United States)

    Barker, Leland A; Harry, John R; Dufek, Janet S; Mercer, John A

    2017-04-01

    Barker, LA, Harry, JR, Dufek, JS, and Mercer, JA. Aerial rotation effects on vertical jump performance among highly skilled collegiate soccer players. J Strength Cond Res 31(4): 932-938, 2017-In soccer matches, jumps involving rotations occur when attempting to head the ball for a shot or pass from set pieces, such as corner kicks, goal kicks, and lob passes. However, the 3-dimensional ground reaction forces used to perform rotational jumping tasks are currently unknown. Therefore, the purpose of this study was to compare bilateral, 3-dimensional, and ground reaction forces of a standard countermovement jump (CMJ0) with those of a countermovement jump with a 180° rotation (CMJ180) among Division-1 soccer players. Twenty-four participants from the soccer team of the University of Nevada performed 3 trials of CMJ0 and CMJ180. Dependent variables included jump height, downward and upward phase times, vertical (Fz) peak force and net impulse relative to mass, and medial-lateral and anterior-posterior force couple values. Statistical significance was set a priori at α = 0.05. CMJ180 reduced jump height, increased the anterior-posterior force couple in the downward and upward phases, and increased upward peak Fz (p ≤ 0.05). All other variables were not significantly different between groups (p > 0.05). However, we did recognize that downward peak Fz trended lower in the CMJ0 condition (p = 0.059), and upward net impulse trended higher in the CMJ0 condition (p = 0.071). It was concluded that jump height was reduced during the rotational jumping task, and rotation occurred primarily via AP ground reaction forces through the entire countermovement jump. Coaches and athletes may consider additional rotational jumping in their training programs to mediate performance decrements during rotational jump tasks.

  18. Assessment of Spatial Navigation and Docking Performance During Simulated Rover Tasks

    Science.gov (United States)

    Wood, S. J.; Dean, S. L.; De Dios, Y. E.; Moore, S. T.

    2010-01-01

    INTRODUCTION: Following long-duration exploration transits, pressurized rovers will enhance surface mobility to explore multiple sites across Mars and other planetary bodies. Multiple rovers with docking capabilities are envisioned to expand the range of exploration. However, adaptive changes in sensorimotor and cognitive function may impair the crew s ability to safely navigate and perform docking tasks shortly after transition to the new gravitoinertial environment. The primary goal of this investigation is to quantify post-flight decrements in spatial navigation and docking performance during a rover simulation. METHODS: Eight crewmembers returning from the International Space Station will be tested on a motion simulator during four pre-flight and three post-flight sessions over the first 8 days following landing. The rover simulation consists of a serial presentation of discrete tasks to be completed within a scheduled 10 min block. The tasks are based on navigating around a Martian outpost spread over a 970 sq m terrain. Each task is subdivided into three components to be performed as quickly and accurately as possible: (1) Perspective taking: Subjects use a joystick to indicate direction of target after presentation of a map detailing current orientation and location of the rover with the task to be performed. (2) Navigation: Subjects drive the rover to the desired location while avoiding obstacles. (3) Docking: Fine positioning of the rover is required to dock with another object or align a camera view. Overall operator proficiency will be based on how many tasks the crewmember can complete during the 10 min time block. EXPECTED RESULTS: Functionally relevant testing early post-flight will develop evidence regarding the limitations to early surface operations and what countermeasures are needed. This approach can be easily adapted to a wide variety of simulated vehicle designs to provide sensorimotor assessments for other operational and civilian populations.

  19. School performance in children with type 1 diabetes: a contemporary population-based study.

    Science.gov (United States)

    Cooper, Matthew N; McNamara, Kaitrin A R; de Klerk, Nicholas H; Davis, Elizabeth A; Jones, Timothy W

    2016-03-01

    Our aim was to examine the school performance of children with type 1 diabetes in comparison to their peers, exploring changes over time, and the impact of clinical factors on school performance. The study included data on 666 children with type 1 diabetes from the Western Australia Children's Diabetes Database. (WACDD), a population-based registry, and 3260 school and school year matched non-diabetic children. Records from the National Assessment Program - Literacy and Numeracy (NAPLAN) (2008-2011), which examines four educational outcome domains and is administered annually to all years 3, 5, 7, and 9 children in Australia, were sourced for both groups. Clinical data were obtained for the children with diabetes from the WACDD. No significant difference was observed between those with type 1 diabetes and their peers, across any of the tested domains and school years analysed. No decline over time was observed, and no decline following diagnosis was observed. Type 1 diabetes was associated with decreased school attendance, 3% fewer days attended per year. Poorer glycaemic control [higher haemoglobin A1c (HbA1c)] was associated with a lower test score [0.2-0.3 SD per 1% (10.9 mmol/mol) increase in HbA1c], and with poorer attendance [1.8% decrease per 1% (10.9 mmol/mol) increase in HbA1c]. No association was observed with history of severe hypoglycaemia, diabetic ketoacidosis or age of onset and school test scores. These results suggest that type 1 diabetes is not associated with a significant decrement in school performance, as assessed by NAPLAN. The association of poorer glycaemic control with poorer school performance serves as further evidence for clinicians to focus on improving glycaemic control. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Foam Rolling for Delayed-Onset Muscle Soreness and Recovery of Dynamic Performance Measures

    Science.gov (United States)

    Pearcey, Gregory E. P.; Bradbury-Squires, David J.; Kawamoto, Jon-Erik; Drinkwater, Eric J.; Behm, David G.; Button, Duane C.

    2015-01-01

    Context: After an intense bout of exercise, foam rolling is thought to alleviate muscle fatigue and soreness (ie, delayed-onset muscle soreness [DOMS]) and improve muscular performance. Potentially, foam rolling may be an effective therapeutic modality to reduce DOMS while enhancing the recovery of muscular performance. Objective: To examine the effects of foam rolling as a recovery tool after an intense exercise protocol through assessment of pressure-pain threshold, sprint time, change-of-direction speed, power, and dynamic strength-endurance. Design: Controlled laboratory study. Setting: University laboratory. Patients or Other Participants: A total of 8 healthy, physically active males (age = 22.1 ± 2.5 years, height = 177.0 ± 7.5 cm, mass = 88.4 ± 11.4 kg) participated. Intervention(s): Participants performed 2 conditions, separated by 4 weeks, involving 10 sets of 10 repetitions of back squats at 60% of their 1-repetition maximum, followed by either no foam rolling or 20 minutes of foam rolling immediately, 24, and 48 hours postexercise. Main Outcome Measure(s): Pressure-pain threshold, sprint speed (30-m sprint time), power (broad-jump distance), change-of-direction speed (T-test), and dynamic strength-endurance. Results: Foam rolling substantially improved quadriceps muscle tenderness by a moderate to large amount in the days after fatigue (Cohen d range, 0.59 to 0.84). Substantial effects ranged from small to large in sprint time (Cohen d range, 0.68 to 0.77), power (Cohen d range, 0.48 to 0.87), and dynamic strength-endurance (Cohen d = 0.54). Conclusions: Foam rolling effectively reduced DOMS and associated decrements in most dynamic performance measures. PMID:25415413

  1. Variable School Start Times and Middle School Student's Sleep Health and Academic Performance.

    Science.gov (United States)

    Lewin, Daniel S; Wang, Guanghai; Chen, Yao I; Skora, Elizabeth; Hoehn, Jessica; Baylor, Allison; Wang, Jichuan

    2017-08-01

    Improving sleep health among adolescents is a national health priority and implementing healthy school start times (SSTs) is an important strategy to achieve these goals. This study leveraged the differences in middle school SST in a large district to evaluate associations between SST, sleep health, and academic performance. This cross-sectional study draws data from a county-wide surveillance survey. Participants were three cohorts of eighth graders (n = 26,440). The school district is unique because SST ranged from 7:20 a.m. to 8:10 a.m. Path analysis and probit regression were used to analyze associations between SST and self-report measures of weekday sleep duration, grades, and homework controlling for demographic variables (sex, race, and socioeconomic status). The independent contributions of SST and sleep duration to academic performance were also analyzed. Earlier SST was associated with decreased sleep duration (χ 2  = 173, p academic performance, and academic effort. Path analysis models demonstrated the independent contributions of sleep duration, SST, and variable effects for demographic variables. This is the first study to evaluate the independent contributions of SST and sleep to academic performance in a large sample of middle school students. Deficient sleep was prevalent, and the earliest SST was associated with decrements in sleep and academics. These findings support the prioritization of policy initiatives to implement healthy SST for younger adolescents and highlight the importance of sleep health education disparities among race and gender groups. Copyright © 2017 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  2. Understanding protocol performance: impact of test performance.

    Science.gov (United States)

    Turner, Robert G

    2013-01-01

    This is the second of two articles that examine the factors that determine protocol performance. The objective of these articles is to provide a general understanding of protocol performance that can be used to estimate performance, establish limits on performance, decide if a protocol is justified, and ultimately select a protocol. The first article was concerned with protocol criterion and test correlation. It demonstrated the advantages and disadvantages of different criterion when all tests had the same performance. It also examined the impact of increasing test correlation on protocol performance and the characteristics of the different criteria. To examine the impact on protocol performance when individual tests in a protocol have different performance. This is evaluated for different criteria and test correlations. The results of the two articles are combined and summarized. A mathematical model is used to calculate protocol performance for different protocol criteria and test correlations when there are small to large variations in the performance of individual tests in the protocol. The performance of the individual tests that make up a protocol has a significant impact on the performance of the protocol. As expected, the better the performance of the individual tests, the better the performance of the protocol. Many of the characteristics of the different criteria are relatively independent of the variation in the performance of the individual tests. However, increasing test variation degrades some criteria advantages and causes a new disadvantage to appear. This negative impact increases as test variation increases and as more tests are added to the protocol. Best protocol performance is obtained when individual tests are uncorrelated and have the same performance. In general, the greater the variation in the performance of tests in the protocol, the more detrimental this variation is to protocol performance. Since this negative impact is increased as

  3. Prevention of vision loss protects against age-related impairment in learning and memory performance in DBA/2J mice.

    Science.gov (United States)

    Wong, Aimée A; Brown, Richard E

    2013-01-01

    The DBA/2J mouse is a model of pigmentary glaucoma in humans as it shows age-related increases in intraocular pressure (IOP), retinal ganglion cell death and visual impairment. Previously, we showed that visual ability declines from 9 to 12 months of age and visual impairment is correlated with poor learning and memory performance in visuo-spatial tasks but not in tasks that do not depend on visual cues. To test the "sensory impairment" hypothesis of aging, which postulates that sensory impaired individuals are disadvantaged in their performance on psychometric tests as a direct result of difficulties in sensory perception, we treated DBA/2J mice with a conventional glaucoma medication used in humans (Timoptic-XE, 0.00, 0.25, or 0.50%) daily from 9 weeks to 12 months of age to determine whether prevention of vision loss prevented the decline in visuo-spatial learning and memory performance. At all ages tested (3, 6, 9, and 12 months of age), mice treated with Timoptic-XE (0.25 and 0.50%) maintained a high level of performance, while 12 month old control mice (0.00%) exhibited impaired performance in visually-dependent, but not non-visual tasks. These results demonstrate that when sensory function is preserved, cognitive performance is normalized. Thus, as in many aging humans, DBA/2J mice show age-related decrements in performance on visually presented cognitive tests, not because of cognitive impairment but as a direct consequence of poor visual ability. Our results demonstrate that age-related impairment in performance in visuo-spatial tasks in DBA/2J mice can be prevented by the preservation of visual ability.

  4. Prevention of vision loss protects against age-related impairment in learning and memory performance in DBA/2J mice

    Directory of Open Access Journals (Sweden)

    Aimee eWong

    2013-09-01

    Full Text Available The DBA/2J mouse is a model of pigmentary glaucoma in humans as it shows age‐related increases in intraocular pressure, retinal ganglion cell death and visual impairment. Previously, we showed that visual ability declines from 9 ‐12 months of age and visual impairment is correlated with poor learning and memory performance in visuo‐spatial tasks but not in tasks that do not depend on visual cues. To test the sensory impairment hypothesis of aging, which postulates that sensory impaired individuals are disadvantaged in their performance on psychometric tests as a direct result of difficulties in sensory perception, we treated DBA/2J mice with a conventional glaucoma medication used in humans (Timoptic‐XE, 0.00, 0.25 or 0.50% daily from 9 weeks to 12 months of age to determine whether prevention of vision loss prevented the decline in visuo-spatial learning and memory performance. At all ages tested (3, 6, 9 and 12 months of age, mice treated with Timoptic-XE (0.25 and 0.50% maintained a high level of performance, while 12 month old control mice (0.00% exhibited impaired performance in visually‐dependent, but not non‐visual tasks. These results demonstrate that when sensory function is preserved, cognitive performance is normalized. Thus, as in many aging humans, DBA/2J mice show age-related decrements in performance on visually presented cognitive tests, not because of cognitive impairment but as a direct consequence of poor visual ability. Our results demonstrate that age-related impairment in performance in visuo-spatial tasks in DBA/2J mice can be prevented by the preservation of visual ability.

  5. Textiles Performance Testing Facilities

    Data.gov (United States)

    Federal Laboratory Consortium — The Textiles Performance Testing Facilities has the capabilities to perform all physical wet and dry performance testing, and visual and instrumental color analysis...

  6. Fifteen-hour day shifts have little effect on the performance of taskwork by anaesthesia trainees during uncomplicated clinical simulation.

    Science.gov (United States)

    Garden, A L; Robinson, B J; Kappus, L J; Macleod, I; Gander, P H

    2012-11-01

    Shiftwork and work-hour limits for junior doctors are now well established in hospital work patterns. In order to ensure that trainees have adequate exposure to daytime elective surgical procedures, there is a tendency to have long shifts that include an after-hours component. However, long shifts can cause performance decrement due to time-on-task fatigue. In addition, shifts that encroach upon sleep time result in sleep loss. Using a high-fidelity patient simulation environment, we undertook a randomised, controlled trial to examine fatigue effects. A within-subjects comparison was used to evaluate the effect of 15-hour day shifts on the performance of 12 anaesthesia registrars. Preoperative assessment, machine check and taskwork using 42 task categories were evaluated. In both conditions, there was failure to meet current guidelines for preoperative evaluation or machine check, and when fatigued there was a 'trend' (P=0.06) to a reduction in the number of items in the machine check. With increase in time awake, there was an increase in time taken for explanation to the patient, an increase in mean duration of explanation to the patient, more time looking at the intravenous line or fluids when multi-tasking but less time adjusting the intravenous fluid. These effects are minor during routine uncomplicated induction of anaesthesia, but further investigation is needed to examine fatigue effects during non-routine circumstances.

  7. Influence of P300 latency jitter on event related potential-based brain-computer interface performance

    Science.gov (United States)

    Aricò, P.; Aloise, F.; Schettini, F.; Salinari, S.; Mattia, D.; Cincotti, F.

    2014-06-01

    Objective. Several ERP-based brain-computer interfaces (BCIs) that can be controlled even without eye movements (covert attention) have been recently proposed. However, when compared to similar systems based on overt attention, they displayed significantly lower accuracy. In the current interpretation, this is ascribed to the absence of the contribution of short-latency visual evoked potentials (VEPs) in the tasks performed in the covert attention modality. This study aims to investigate if this decrement (i) is fully explained by the lack of VEP contribution to the classification accuracy; (ii) correlates with lower temporal stability of the single-trial P300 potentials elicited in the covert attention modality. Approach. We evaluated the latency jitter of P300 evoked potentials in three BCI interfaces exploiting either overt or covert attention modalities in 20 healthy subjects. The effect of attention modality on the P300 jitter, and the relative contribution of VEPs and P300 jitter to the classification accuracy have been analyzed. Main results. The P300 jitter is higher when the BCI is controlled in covert attention. Classification accuracy negatively correlates with jitter. Even disregarding short-latency VEPs, overt-attention BCI yields better accuracy than covert. When the latency jitter is compensated offline, the difference between accuracies is not significant. Significance. The lower temporal stability of the P300 evoked potential generated during the tasks performed in covert attention modality should be regarded as the main contributing explanation of lower accuracy of covert-attention ERP-based BCIs.

  8. Comparative investigation of novel hetero gate dielectric and drain engineered charge plasma TFET for improved DC and RF performance

    Science.gov (United States)

    Yadav, Dharmendra Singh; Verma, Abhishek; Sharma, Dheeraj; Tirkey, Sukeshni; Raad, Bhagwan Ram

    2017-11-01

    Tunnel-field-effect-transistor (TFET) has emerged as one of the most prominent devices to replace conventional MOSFET due to its ability to provide sub-threshold slope below 60 mV/decade (SS ≤ 60 mV/decade) and low leakage current. Despite this, TFETs suffer from ambipolar behavior, lower ON-state current, and poor RF performance. To address these issues, we have introduced drain and gate work function engineering with hetero gate dielectric for the first time in charge plasma based doping-less TFET (DL TFET). In this, the usage of dual work functionality over the drain region significantly reduces the ambipolar behavior of the device by varying the energy barrier at drain/channel interface. Whereas, the presence of dual work function at the gate terminal increases the ON-state current (ION). The combined effect of dual work function at the gate and drain electrode results in the increment of ON-state current (ION) and decrement of ambipolar conduction (Iambi) respectively. Furthermore, the incorporation of hetero gate dielectric along with dual work functionality at the drain and gate electrode provides an overall improvement in the performance of the device in terms of reduction in ambipolarity, threshold voltage and sub-threshold slope along with improved ON-state current and high frequency figures of merit.

  9. The Augmented Performer and the Performative Augmentation

    DEFF Research Database (Denmark)

    Kallionpaa, Maria; Gasselseder, Hans-Peter

    2016-01-01

    Composers, performers, and listeners usually regard musical compositions as unchangeable entities, which limits the composition techniques and decreases the originality of performers ́ interpretations, thus leading to a stagnation of classical music culture. The significance and possibilities of ...

  10. High performance work practices, innovation and performance

    DEFF Research Database (Denmark)

    Jørgensen, Frances; Newton, Cameron; Johnston, Kim

    2013-01-01

    Research spanning nearly 20 years has provided considerable empirical evidence for relationships between High Performance Work Practices (HPWPs) and various measures of performance including increased productivity, improved customer service, and reduced turnover. What stands out from......, and Africa to examine these various questions relating to the HPWP-innovation-performance relationship. Each paper discusses a practice that has been identified in HPWP literature and potential variables that can facilitate or hinder the effects of these practices of innovation- and performance...

  11. Effect of Ramadan intermittent fasting on aerobic and anaerobic performance and perception of fatigue in male elite judo athletes.

    Science.gov (United States)

    Chaouachi, Anis; Coutts, Aaron J; Chamari, Karim; Wong, Del P; Chaouachi, Mustapha; Chtara, Moktar; Roky, Rachida; Amri, Mohamed

    2009-12-01

    The aim of the present study was to evaluate the influence of the Ramadan intermittent fast (RIF) on aerobic and anaerobic exercise performance in elite judo athletes (Judokas) maintaining their usual training loads. Physical performance tests (squat jump [SJ]), countermovement jump [CMJ], 30-second repeated jump, 30-m sprint, and the multistage fitness test) and fatigue scores were measured in 15 elite Judokas on 4 occasions: before Ramadan (T1), at the beginning of Ramadan (T2), at the end of Ramadan (T3) and 3 weeks after Ramadan. Results showed that 30-m sprint performance, multistage shuttle run test, SJ, and CMJ did not change during Ramadan. However, average power during the 30-second repeated jump test was slightly lower at the end of Ramadan (22.4 +/- 2.3 W/kg; P Ramadan (23.4 +/- 2.3 W/kg). There was a minor reduction of 1.3 kg in body mass and an increase in total fatigue scores (T2, 19 +/- 5; T3, 16 +/- 4; both P Ramadan in comparison with the control period (T1, 12 +/- 3). These results show that the RIF has little effect on aerobic performance and on very short duration sprinting and jumping test performance in elite Judokas. Additionally, experienced athletes can maintain both sufficient energy intake and normal training loads during the RIF. The slight reduction in the 30-second jump test may be associated with reduced central drive and body mass. Collectively, these results suggest that the RIF has little effect on the performance of experienced Judokas, but Muslim athletes who train during the RIF should carefully periodize their training load and monitor their food intake and fatigue levels to avoid performance decrements.

  12. Do baseline executive functions mediate prospective memory performance under a moderate dose of alcohol?

    Directory of Open Access Journals (Sweden)

    James Hugo Smith-Spark

    2016-08-01

    Full Text Available Prospective memory (PM is memory for delayed intentions. While deleterious effects of acute doses of alcohol on PM have been documented previously using between-subjects comparisons, the current study adopted a single blind placebo-controlled within-subjects design to explore whether the extent to which alcohol-related impairments in PM are mediated by executive functions (EFs. To this end, 52 male social drinkers with no history of substance-related treatment were tested using two parallel versions of a clinical measure of PM (the Memory for Intentions Test; Raskin, Buckheit & Sherrod, 2010, and a battery of EF measures. Testing took place on two occasions, with the order of administration of the alcohol and placebo conditions being fully counterbalanced. Overall, PM was worse under alcohol and participants showed deficits on five of the six subscales making up the clinical test. Hierarchical multiple regression analyses demonstrated that EFs did not predict PM performance decrements overall but did predict performance when time cues were presented and when verbal responses were required. Phonemic fluency was the strongest of the EF predictors; a greater capacity to gain controlled access to information in long-term memory predicted a smaller difference between placebo- and alcohol-related performance on both the time cue and verbal response scales. Prospective memory is crucial to compliance with, and response to, both therapy programmes and alcohol harm prevention campaigns. The results indicate that individual differences in cognitive function need to be taken into account when designing such interventions in order to increase their effectiveness.

  13. Effect Of Plyometric Training On Vertical Jump Performance And Neuromuscular Adaptation In Volleyball Player

    Directory of Open Access Journals (Sweden)

    Dara Hosseini

    2012-12-01

    Full Text Available The purpose of this study was to examine the effectiveness of 12-week plyometric training on vertical jump performance (Vj, maximal surface EMG, M-wave amplitude, Mwave latency, and nerve conduction velocity (NCV in men volleyball player. Thirty junior high school volleyball players' volunteers (age: 17.53 0.74; Height: 177.67 3.14; Weight: 61.31 5.32 were divided into plyometric training [PT] (n=15 and control group[c] (n=15. PT group trained so.w' but C group didn't participate in this training. Both groups were pre- and post tested in EMG, M-wave parameters, NCV and Vj test. Tow way ANOVA (group*time interaction and Bonferroni post hoes test demonstrated significant differences (P<0.05 in PT group of pre to post test in VJ performance (9.67 % and in M-wave latency 16.55 % t ; nerve conduction velocity 14.19 % t ; there is no significant differences in IEMG (4.6 5 % J, and M-wave amplitude (20.91 % t , but there is no significant improvement during this period in control group. Comparison between groups after 12wk showed that there was a significant improvement in Latency (16.74 % J, and NCV (19.10% t in PT group during the course of the study than C group (P<0.05. based on the results of this study, it is possible to conclude that coaches and trainers consider PT as a strategy for increasing volleyball players' explosive performance that this may have taken place in neuromuscular responses such as; optimizing motor unites (MU pattern, optimizing MUs recruitment, augmentation in nerve conduction velocity, decrement in reflex excitability of the motor pool.

  14. Do Baseline Executive Functions Mediate Prospective Memory Performance under a Moderate Dose of Alcohol?

    Science.gov (United States)

    Smith-Spark, James H; Moss, Antony C; Dyer, Kyle R

    2016-01-01

    Prospective memory (PM) is memory for delayed intentions. While deleterious effects of acute doses of alcohol on PM have been documented previously using between-subjects comparisons, the current study adopted a single blind placebo-controlled within-subjects design to explore whether the extent to which alcohol-related impairments in PM are mediated by executive functions (EFs). To this end, 52 male social drinkers with no history of substance-related treatment were tested using two parallel versions of a clinical measure of PM (the Memory for Intentions Test; Raskin et al., 2010), and a battery of EF measures. Testing took place on two occasions, with the order of administration of the alcohol and placebo conditions being fully counterbalanced. Overall, PM was worse under alcohol and participants showed deficits on five of the six subscales making up the clinical test. Hierarchical multiple regression analyses demonstrated that EFs did not predict PM performance decrements overall but did predict performance when time cues were presented and when verbal responses were required. Phonemic fluency was the strongest of the EF predictors; a greater capacity to gain controlled access to information in long-term memory predicted a smaller difference between placebo- and alcohol-related performance on both the time cue and verbal response scales. PM is crucial to compliance with, and response to, both therapy programs and alcohol harm prevention campaigns. The results indicate that individual differences in cognitive function need to be taken into account when designing such interventions in order to increase their effectiveness.

  15. The effects of black tea and other beverages on aspects of cognition and psychomotor performance.

    Science.gov (United States)

    Hindmarch, I; Quinlan, P T; Moore, K L; Parkin, C

    1998-10-01

    Nineteen healthy volunteers ingested 400 ml black tea, coffee, caffeinated water, decaffeinated tea or plain water on three occasions through the day (0900, 1400 and 1900 hours). A 2 x 2 factorial design with caffeine (0, 100 mg) and beverage type (water, tea) was employed, with coffee (100 mg caffeine) as a positive internal control, based on a five-way crossover. A psychometric test battery comprising critical flicker fusion (CFF), choice reaction time (CRT), short-term memory (STM) and subjective sedation (LARS) was performed at regular intervals throughout the day, and intensively so immediately following each beverage. Consumption of tea compared to water was associated with transient improvements in performance (CFF) within 10 min of ingestion and was not affected by the time of day. Caffeine ingestion was associated with a rapid (10 min) and persistent reduction in subjective sedation values (LARS), again independent of time of day, but did not acutely alter CFF threshold. Over the whole day, consumption of tea rather than water, and of caffeinated compared to decaffeinated beverages, largely prevented the steady decline in alertness (LARS) and cognitive capacity observed with water ingestion. The effects of tea and coffee were similar on all measures, except that tea consumption was associated with less variation in CFF over the whole day. No significant treatment effects were apparent in the data for the STM. Tea ingestion is associated with rapid increases in alertness and information processing capacity and tea drinking throughout the day largely prevents the diurnal pattern of performance decrements found with the placebo (no caffeine) condition. It appears that the effects of tea and coffee were not entirely due to caffeine per se; other factors either intrinsic to the beverage (e.g. sensory attributes or the presence of other biologically active substances) or of a psychological nature (e.g. expectancy) are likely to play a significant role in

  16. Long Duration Head Down Tilt Bed Rest and Spaceflight Effects on Neurocognitive Performance: Extent, Longevity and Neural Bases

    Science.gov (United States)

    Seidler, R. D.; Mulavara, A. P.; Koppelmans, V.; Cassady, K.; Yuan, P.; Kofman, I. S.; De Dios, Y. E.; Riascos-Castaneda, R. F.; Wood, S. J.; Bloomberg, J. J.

    2017-01-01

    We have recently completed a long duration head down tilt bed rest (HDBR) study in which we performed structural and functional magnetic resonance brain imaging to identify the relationships between changes in neurocognitive function and neural structural alterations in a spaceflight analog environment. We are also collecting the same measures in crewmembers prior to and following a six month International Space Station mission. We will present data demonstrating that bed rest resulted in functional mobility and balance deterioration with recovery post-HDBR. We observed numerous changes in brain structure, function, and connectivity relative to a control group which were associated with pre to post bed rest changes in sensorimotor function. For example, gray matter volume (GMv) increased in posterior parietal areas and decreased in frontal regions. GMv increases largely overlapped with fluid decreases and vice versa. Larger increases in precentral gyrus (M1)/ postcentral gyrus (S1+2) GMv and fluid decreases were associated with smaller balance decrements. Vestibular activation in the bilateral insular cortex increased with bed rest and subsequently recovered. Larger increases in vestibular activation in multiple brain regions were associated with greater decrements in balance and mobility. We found connectivity increases between left M1 with right S1+2 and the superior parietal lobule, and right vestibular cortex with the cerebellum. Decreases were observed between right Lobule VIII with right S1+2 and the supramarginal gyrus, right posterior parietal cortex (PPC) with occipital regions, and the right superior posterior fissure with right Crus I and II. Connectivity strength between left M1 and right S1+2/superior parietal lobule increased the most in individuals that exhibited the least balance impairments. In sum, we observed HDBR-related changes in measures of brain structure, function, and network connectivity, which correlated with indices of sensorimotor

  17. Effects of 3-Day Serial Sodium Bicarbonate Loading on Performance and Physiological Parameters During a Simulated Basketball Test in Female University Players.

    Science.gov (United States)

    Delextrat, Anne; MacKessy, Sinead; Arceo-Rendon, Luis; Scanlan, Aaron; Ramsbottom, Roger; Calleja-González, Julio

    2018-01-18

    The aim of this study was to investigate the effect of 3-day serial sodium bicarbonate ingestion on repeated sprint and jump performance. Fifteen female university basketball players (23.3±3.4 years; 173.1±5.8 cm; 65.8±6.3 kg; 23.6±4.9% body fat) ingested 0.4 g·kg -1 of body mass of sodium bicarbonate or placebo for 3 days (split in 3 equal daily doses), before completing a simulated basketball exercise. Sprint and circuit times, jump heights, performance decrements and gastrointestinal (GI) side effects were recorded during the test and blood lactate concentration was measured pre- and post-test. Sodium bicarbonate supplementation led to significant decreases in mean sprint times (1.34±0.23 vs. 1.70±0.41 s, p=0.008, 95% CI: -0.54 to -0.10 s) and mean circuit times (30.6±2.0 vs. 31.3±2.0 s, p=0.044) and significantly greater mean jump height (26.8 (range 25.2-34.2) vs. 26.0 (range 25.6-33.6) cm, p=0.013) compared to placebo. Performance decrement was significantly less for sprints with sodium bicarbonate compared to placebo (9.9 (range 3.4-37.0) vs. 24.7 (range 4.1-61.3) %, p=0.013), but not different for jumps (13.1±4.5 vs. 12.5±.3.1%, p=0.321) between conditions. No differences in GI side effects were noted between conditions. Significantly greater post-exercise blood lactate concentrations were measured in the sodium bicarbonate condition compared to the placebo condition (8.2±2.8 vs. 6.6±2.4 mmol.L -1 , p=0.010). This study is the first to show that serial loading of sodium bicarbonate is effective for basketball players to improve repeated sprint and jump performance during competition, or withstand greater training load during practice sessions without any GI side effects.

  18. Visual Performance Challenges to Low-Frequency Perturbations After Long-Duration Space Flight, and Countermeasure Development

    Science.gov (United States)

    Mulavara, Ajitkumar; Wood, Scott; Fiedler, Matthew; Kofman, Igor; Kulecz, Walter B.; Miller, Chris; Peters, Brian; Serrador, Jorge; Cohen, Helen; Reschke, Millard; hide

    2010-01-01

    Astronauts experience sensorimotor disturbances after long-duration space flight. After a water landing, crewmembers may need to egress the vehicle within a few minutes for safety and operational reasons in various sea state conditions. Exposure to even low-frequency motions induced by sea conditions surrounding a vessel can cause significant motor control problems affecting critical functions. The first objective of this study was to document human visual performance during simulated wave motion below 2.0 Hz. We examined the changes in accuracy and reaction time when subjects performed a visual target acquisition task in which the location of the target was offset vertically during horizontal rotation at an oscillating frequency of 0.8 Hz. The main finding was that both accuracy and reaction time varied as a function of target location, with greater performance decrements occurring when vertical targets were acquired at perturbing frequencies of 0.8 Hz in the horizontal plane. A second objective was to develop a countermeasure, base d on stochastic resonance (SR), to enhance sensorimotor capabilities with the aim of facilitating rapid adaptation to gravitational transitions after long-duration space flight. SR is a mechanism by which noise can enhance the response of neural systems to relevant sensory signals. Recent studies have shown that applying imperceptible stochastic electrical stimulation to the vestibular system (SVS) significantly improved balance and oculomotor responses. This study examined the effectiveness of SVS on improving balance performance. Subjects performed a standard balance task while bipolar SVS was applied to the vestibular system using constant current stimulation through electrodes placed over the mastoid process. The main finding of this study was that balance performance with the application of SR showed significant improvement in the range of 10%-25%. Ultimately an SR-based countermeasure might be fielded either as preflight training

  19. Performing surgery: commonalities with performers outside medicine

    Directory of Open Access Journals (Sweden)

    Roger Lister Kneebone

    2016-08-01

    Full Text Available This paper argues for the inclusion of surgery within the canon of performance science. The world of medicine presents rich, complex but relatively under-researched sites of performance. Performative aspects of clinical practice are overshadowed by a focus on the processes and outcomes of medical care, such as diagnostic accuracy and the results of treatment. The primacy of this ‘clinical’ viewpoint - framed by clinical professionals as the application of medical knowledge - hides resonances with performance in other domains. Yet the language of performance is embedded in the culture of surgery - surgeons ‘perform’ operations, work in an operating ‘theatre’ and use ‘instruments’. This paper asks what might come into view if we take this performative language at face value and interrogate surgery from the perspective of performance science. It addresses the following questions: 1.To what extent and in what ways can surgical practice (both consultation and operation be considered as performance?2.How does comparison with two domains domains of non-surgical performance (close-up magic and puppetry illuminate understanding of surgical practice as performance?3.In what ways might including surgery within the canon of performance studies enrich the field of performance science?Two detailed case studies over 5 years with magicians (71.5 hours contact time and puppeteers (50.5 hours contact time identified performative aspects of surgical practice from the perspectives of professionals (as individuals or in groups and audiences. Physical simulation provided a means for non-clinicians to access and experience elements of the surgical world, acting as a prompt for discussion. Thematic analysis was used to establish themes and sub-themes.Key themes were: 1 clinical consultation can be viewed as ‘close-up live performance with a very small audience’ and 2 operative surgery can be viewed as ‘reading bodies within a dextrous team

  20. Display rules versus display autonomy: emotion regulation, emotional exhaustion, and task performance in a call center simulation.

    Science.gov (United States)

    Goldberg, Lori Sideman; Grandey, Alicia A

    2007-07-01

    "Service with a smile" is satisfying for the customer, but such display rules may be costly to the employee and the organization. Most previous research on such costs has used self-reported and cross-sectional designs. The authors use an experimental approach to test tenets of resource depletion theories; specifically, whether the self-regulation of emotions required by display rules depletes energy and attentional resources during a service encounter. Using a call center simulation with three "customer" interactions, the authors found that participants given positive display rules (e.g., be enthusiastic and hide frustration) reported more postsimulation exhaustion and made more errors on the order form compared to those with display autonomy. Customer hostility during one of the calls also increased exhaustion overall and the number of errors during that specific call, though proposed interactions with display rules were not supported. Surface-level emotion regulation, but not deep-level, was the mechanism for the energy depletion effect of display rules, while display rules had a direct effect on performance decrements. Theoretical and practical implications for display rules as part of job requirements are discussed. Copyright 2007 APA

  1. A comparison of the effects of transcranial direct current stimulation and caffeine on vigilance and cognitive performance during extended wakefulness.

    Science.gov (United States)

    McIntire, Lindsey K; McKinley, R Andy; Goodyear, Chuck; Nelson, Justin

    2014-01-01

    Sleep deprivation from extended duty hours is a common complaint for many occupations. Caffeine is one of the most common countermeasures used to combat fatigue. However, the benefits of caffeine decline over time and with chronic use. Our objective was to evaluate the efficacy of anodal transcranial direct current stimulation (tDCS) applied to the pre-frontal cortex at 2 mA for 30 min to remediate the effects of sleep deprivation and to compare the behavioral effects of tDCS with those of caffeine. Three groups of 10 participants each received either active tDCS with placebo gum, caffeine gum with sham tDCS, or sham tDCS with placebo gum during 30 h of extended wakefulness. Our results show that tDCS prevented a decrement in vigilance and led to better subjective ratings for fatigue, drowsiness, energy, and composite mood compared to caffeine and control in sleep-deprived individuals. Both the tDCS and caffeine produced similar improvements in latencies on a short-term memory task and faster reaction times in a psychomotor task when compared to the placebo group. Interestingly, changes in accuracy for the tDCS group were not correlated to changes in mood; whereas, there was a relationship for the caffeine and sham groups. Our data suggest that tDCS could be a useful fatigue countermeasure and may be more beneficial than caffeine since boosts in performance and mood last several hours. Published by Elsevier Inc.

  2. Java Performance Mysteries

    Directory of Open Access Journals (Sweden)

    Maldikar Pranita

    2016-01-01

    The contributions of this paper are (1 Observing Java performance mysteries in the cloud, (2 Identifying the sources of performance mysteries, and (3 Obtaining optimal and reproducible performance data.

  3. LTBP bridge performance primer.

    Science.gov (United States)

    2013-12-01

    "The performance of bridges is critical to the overall performance of the highway transportation system in the United States. However, many critical aspects of bridge performance are not well understood. The reasons for this include the extreme diver...

  4. Distributed performance counters

    Science.gov (United States)

    Davis, Kristan D; Evans, Kahn C; Gara, Alan; Satterfield, David L

    2013-11-26

    A plurality of first performance counter modules is coupled to a plurality of processing cores. The plurality of first performance counter modules is operable to collect performance data associated with the plurality of processing cores respectively. A plurality of second performance counter modules are coupled to a plurality of L2 cache units, and the plurality of second performance counter modules are operable to collect performance data associated with the plurality of L2 cache units respectively. A central performance counter module may be operable to coordinate counter data from the plurality of first performance counter modules and the plurality of second performance modules, the a central performance counter module, the plurality of first performance counter modules, and the plurality of second performance counter modules connected by a daisy chain connection.

  5. Control mechanism to prevent correlated message arrivals from degrading signaling no. 7 network performance

    Science.gov (United States)

    Kosal, Haluk; Skoog, Ronald A.

    1994-04-01

    Signaling System No. 7 (SS7) is designed to provide a connection-less transfer of signaling messages of reasonable length. Customers having access to user signaling bearer capabilities as specified in the ANSI T1.623 and CCITT Q.931 standards can send bursts of correlated messages (e.g., by doing a file transfer that results in the segmentation of a block of data into a number of consecutive signaling messages) through SS7 networks. These message bursts with short interarrival times could have an adverse impact on the delay performance of the SS7 networks. A control mechanism, Credit Manager, is investigated in this paper to regulate incoming traffic to the SS7 network by imposing appropriate time separation between messages when the incoming stream is too bursty. The credit manager has a credit bank where credits accrue at a fixed rate up to a prespecified credit bank capacity. When a message arrives, the number of octets in that message is compared to the number of credits in the bank. If the number of credits is greater than or equal to the number of octets, then the message is accepted for transmission and the number of credits in the bank is decremented by the number of octets. If the number of credits is less than the number of octets, then the message is delayed until enough credits are accumulated. This paper presents simulation results showing delay performance of the SS7 ISUP and TCAP message traffic with a range of correlated message traffic, and control parameters of the credit manager (i.e., credit generation rate and bank capacity) are determined that ensure the traffic entering the SS7 network is acceptable. The results show that control parameters can be set so that for any incoming traffic stream there is no detrimental impact on the SS7 ISUP and TCAP message delay, and the credit manager accepts a wide range of traffic patterns without causing significant delay.

  6. The effect of ramadan fasting on physical performances, mood state and perceived exertion in young footballers.

    Science.gov (United States)

    Chtourou, Hamdi; Hammouda, Omar; Souissi, Hichem; Chamari, Karim; Chaouachi, Anis; Souissi, Nizar

    2011-09-01

    This study was designed to assess the effects of Ramadan fasting on the profile of mood state and perceived exertion in young soccer players and aerobic and anaerobic performances during the Yo-Yo, repeated sprint ability (RSA) and the Wingate tests. Twenty junior male soccer players completed the Yo-Yo, the RSA, and the Wingate tests on three different occasions: one-week before Ramadan (BR), the second week (SWR) and the fourth week (ER) of Ramadan. The total distance (TD) covered and the estimated maximal aerobic velocity (MAV) during the Yo-Yo test were recorded. During the RSA test, peak power (PP) during each sprint, the percentage of decrement of PP (PD) and total work (Wtotal) were calculated. During the Wingate test, peak (P(peak)) and mean (P(mean)) powers and fatigue index (FI) were recorded. TD and MAV (P=0.01) during the Yo-Yo test and PP (P=0.01, P=0.004, P=0.001, P=0.01, P=0.03 for sprints 1, 2, 3, 4, and 5, respectively) and Wtotal (P=0.02) during the RSA test were significantly higher during BR than ER. Furthermore, muscle fatigue during the RSA test increased significantly from BR to ER (P=0.01). P(peak) and P(mean) during the Wingate test decreased significantly from BR to SWR and ER (PRamadan in comparison with BR. The present study suggests that both aerobic and anaerobic performances during the Yo-Yo, the RSA and the Wingate tests were affected by Ramadan fasting in young soccer players.

  7. Protein catabolism in pregnant snakes (Epicrates cenchria maurus Boidae) compromises musculature and performance after reproduction.

    Science.gov (United States)

    Lourdais, O; Brischoux, F; DeNardo, D; Shine, R

    2004-07-01

    In many species the high energetic demands of reproduction induce a negative energy balance, and thus females must rely on tissue catabolism to complete the reproductive process. Previous works have shown that both fat and protein are energy resources during prolonged fasting in vertebrates. While many ecological studies on energy costs of reproduction have focused on variations in fat stores, the impact of protein investment on the female has not been thoroughly investigated. Notably, as there is no specialized storage form for proteins, intense catabolism is likely to entail structural (musculature) loss that may compromise maternal physical performance after reproduction. Measurements on captive rainbow boas ( Epicrates cenchria maurus) confirm that reproducing females undergo significant protein catabolism (as indicated by elevated plasma uric acid levels) and show considerable musculature loss during gestation (as detected by reduced width of the epaxial muscles). Protein mobilization entailed a significant functional loss that was illustrated by decrements in tests of strength and constriction after parturition. In wild situations, such effects are likely to decrease the snakes' ability to forage and apprehend prey. Hence, the time period needed to recover from reproduction can be extended not only because the female must compensate losses of both fat stores and functional muscle, but also because the ability to do so may be compromised. Performance alteration is likely to be of equal or greater importance than reduced energy stores in the physiological mediation of elevated post-reproduction mortality rates and infrequent reproductive bouts (e.g. biannual or triannual), two common ecological traits of female snakes.

  8. Communication through Performance: Hausa Performance Art ...

    African Journals Online (AJOL)

    The human voice is a natural instrument with a natural capability. Thus, speech with the aid of performance and music has been combined since earliest times to communicate valuable insights into human nature and universal themes of life. Such themes include life, death, good and evil. This paper examined performance ...

  9. Effects of alcohol (BAC 0.5‰) and ecstasy (MDMA 100 mg) on simulated driving performance and traffic safety.

    Science.gov (United States)

    Veldstra, Janet L; Brookhuis, Karel A; de Waard, Dick; Molmans, Barbara H W; Verstraete, Alain G; Skopp, Gisela; Jantos, Ricarda

    2012-08-01

    An increasing number of fatal road-accidents have been reported in which ecstasy was found in the blood of drivers. Although, ecstasy is frequently found to have been used in combination with alcohol, studies on the acute effects of ecstasy co-administered with alcohol on driving performance are relatively rare. The present study was designed to establish the extent of driver impairment as a consequence of ecstasy or combined ecstasy and alcohol use as compared to driving under the influence of 0.3‰, 0.5‰ and 0.8‰ alcohol. Furthermore, subjective performance was also assessed. Alcohol and ecstasy mainly influenced automated driving performance such as lateral and speed control. However, small to no effects of the substances were found on more complex driving behaviour. Overall, variance within the different driving measures was high especially when participants were treated with 3.4-methylenedioxy-methamphetamine (MDMA) and alcohol. Furthermore, equivalence testing showed that combined use may lead to impaired driving for some, but not all, drivers. Participants rated their own performance to be slightly worse than normal in both studies. Since driving was actually seriously deteriorated, this was a falsely positive assessment of their condition. The dissociation between subjective perceptions and objective performance decrements are important notions for traffic safety since this may affect a driver's judgement of whether or not it is safe to drive. For example, an intoxicated individual might decide to drive because the feelings of alertness caused by MDMA cloud the impairing effects of other drugs such as alcohol, thereby creating a potentially serious risk for traffic safety.

  10. Biomonitoring of physiological status and cognitive performance of underway submariners undergoing a novel watch-standing schedule

    Science.gov (United States)

    Duplessis, C. A.; Cullum, M. E.; Crepeau, L. J.

    2005-05-01

    Submarine watch-standers adhere to a 6 hour-on, 12 hour-off (6/12) watch-standing schedule, yoking them to an 18-hr day, engendering circadian desynchronization and chronic sleep deprivation. Moreover, the chronic social crowding, shift work, and confinement of submarine life provide additional stressors known to correlate with elevated secretory immunoglobulin A (sIgA) and cortisol levels, reduced performance, immunologic dysfunction, malignancies, infections, gastrointestinal illness, coronary disease, anxiety, and depression. We evaluated an alternative, compressed, fixed work schedule designed to enhance circadian rhythm entrainment, sleep hygiene, performance, and health on 10 underway submariners, who followed the alternative and 6/12 schedules for approximately 2 weeks each. We measured subjects" sleep, cognitive performance, and salivary biomarker levels. Pilot analysis of the salivary data on one subject utilizing ELISA suggests elevated biomarker levels of stress. Average PM cortisol levels were 0.2 μg/L (normal range: nondetectable - 0.15 μg/L), and mean sIgA levels were 562 μg/ml (normal range: 100-500 μg/ml). Future research exploiting real-time salivary bioassays, via fluorescent polarimetry technology, identified by the Office of Naval Research (ONR) as a future Naval requirement, allows researchers to address correlations between stress-induced elaboration of salivary biomarkers with physiological and performance decrements, thereby fostering insight into the underway submariner"s psychoimmunological status. This may help identify strategies that enhance resilience to stressors. Specifically, empirically-based modeling can identify optimal watch-standing schedules and stress-mitigating procedures -- within the operational constraints of the submarine milieu and the mission --that foster improved circadian entrainment and reduced stress reactivity, enhancing physiological health, operational performance, safety, and job satisfaction.

  11. Wellness, fatigue and physical performance acclimatisation to a 2-week soccer camp at 3600 m (ISA3600)

    Science.gov (United States)

    Buchheit, Martin; Simpson, Ben M; Garvican-Lewis, Laura A; Hammond, Kristal; Kley, Marlen; Schmidt, Walter F; Aughey, Robert J; Soria, Rudy; Sargent, Charli; Roach, Gregory D; Claros, Jesus C Jimenez; Wachsmuth, Nadine; Gore, Christopher J; Bourdon, Pitre C

    2013-01-01

    Objectives To examine the time course of wellness, fatigue and performance during an altitude training camp (La Paz, 3600 m) in two groups of either sea-level (Australian) or altitude (Bolivian) native young soccer players. Methods Wellness and fatigue were assessed using questionnaires and resting heart rate (HR) and HR variability. Physical performance was assessed using HR responses to a submaximal run, a Yo-Yo Intermittent recovery test level 1 (Yo-YoIR1) and a 20 m sprint. Most measures were performed daily, with the exception of Yo-YoIR1 and 20 m sprints, which were performed near sea level and on days 3 and 10 at altitude. Results Compared with near sea level, Australians had moderate-to-large impairments in wellness and Yo-YoIR1 relative to the Bolivians on arrival at altitude. The acclimatisation of most measures to altitude was substantially slower in Australians than Bolivians, with only Bolivians reaching near sea-level baseline high-intensity running by the end of the camp. Both teams had moderately impaired 20 m sprinting at the end of the camp. Exercise HR had large associations (r>0.5–0.7) with changes in Yo-YoIR1 in both groups. Conclusions Despite partial physiological and perceptual acclimatisation, 2 weeks is insufficient for restoration of physical performance in young sea-level native soccer players. Because of the possible decrement in 20 m sprint time, a greater emphasis on speed training may be required during and after altitude training. The specific time course of restoration for each variable suggests that they measure different aspects of acclimatisation to 3600 m; they should therefore be used in combination to assess adaptation to altitude. PMID:24282195

  12. Examination of Communication Delays on Team Performance: Utilizing the International Space Station (ISS) as a Test Bed for Analog Research

    Science.gov (United States)

    Keeton, K. E.; Slack, K, J.; Schmidt, L. L.; Ploutz-Snyder, R.; Baskin, P.; Leveton, L. B.

    2011-01-01

    Operational conjectures about space exploration missions of the future indicate that space crews will need to be more autonomous from mission control and operate independently. This is in part due to the expectation that communication quality between the ground and exploration crews will be more limited and delayed. Because of potential adverse effects on communication quality, both researchers and operational training and engineering experts have suggested that communication delays and the impact these delays have on the quality of communications to the crew will create performance decrements if crews are not given adequate training and tools to support more autonomous operations. This presentation will provide an overview of a research study led by the Behavioral Health and Performance Element (BHP) of the NASA Human Research Program that examines the impact of implementing a communication delay on ISS on individual and team factors and outcomes, including performance and related perceptions of autonomy. The methodological design, data collection efforts, and initial results of this study to date will be discussed . The results will focus on completed missions, DRATS and NEEMO15. Lessons learned from implementing this study within analog environments will also be discussed. One lesson learned is that the complexities of garnishing a successful data collection campaign from these high fidelity analogs requires perseverance and a strong relationship with operational experts. Results of this study will provide a preliminary understanding of the impact of communication delays on individual and team performance as well as an insight into how teams perform and interact in a space-like environment . This will help prepare for implementation of communication delay tests on the ISS, targeted for Increment 35/36.

  13. Prognostic Performance Metrics

    Data.gov (United States)

    National Aeronautics and Space Administration — This chapter presents several performance metrics for offline evaluation of prognostics algorithms. A brief overview of different methods employed for performance...

  14. Declines in swimming performance with age: a longitudinal study of Masters swimming champions

    Directory of Open Access Journals (Sweden)

    Rubin RT

    2013-03-01

    , the individual profiles indicated performance better than the world record data; these swimmers achieved their times after the world record data were collected in 2005–2006. Conclusion: Declining physiological functional capacity occurs with advancing age, and this is reflected in the performance decrements of aging Masters swimmers. Individual swimmers show different performance trajectories with aging, declines being mitigated by practice, which improves both physiological capacity and swimming technique, particularly in the early years of participation. The longitudinal data of this study indicate that individuals can participate in high-intensity swimming over several decades, competitively improving over those decades until, in some instances, they become world record holders for their age groups. Keywords: physiological functional capacity, geriatric health

  15. Performance na contemporaneidade

    Directory of Open Access Journals (Sweden)

    Yiftah Peled

    2012-01-01

    Full Text Available Analisam-se aqui projetos de arte contemporânea, identificando estratégias de incorporação, deslocamento e participação do público que remetem a uma ampliação da arte da performance. O estudo propõe termos para definir tais estratégias como: performance animada, ready-made performático, performance do agente ficcional, dinâmicas e trocas entre estados de performance, performance íntima e performance interna.

  16. Performance and brain electrical activity during prolonged confinement.

    Science.gov (United States)

    Lorenz, B; Lorenz, J; Manzey, D

    1996-01-01

    A subset of the AGARD-STRES battery including memory search, unstable tracking, and a combination of both tasks (dual-task), was applied repeatedly to the four chamber crew members before, during, and after the 60-day isolation period of EXEMSI. Five ground control group members served as a control group. A subjective state questionnaire was also included. The results were subjected to a quantitative single-subject analysis. Electroencephalograms (EEG) were recorded to permit correlation of changes in task performance with changes in the physiological state. Evaluation of the EEG focused on spectral parameters of spontaneous EEG waves. No physiological data were collected from the control group. Significant decrements in tracking ability were observed in the chamber crew. The time course of these effects followed a triphasic pattern with initial deterioration, intermediate recovery to pre-isolation baseline scores after the first half of the isolation period, and a second deterioration towards the end. None of the control group subjects displayed such an effect. Memory search (speed and accuracy) was only occasionally impaired during isolation, but the control group displayed a similar pattern of changes. It is suggested that a state of decreased alertness causes tracking deterioration, which leads to a reduced efficiency of sustained cue utilization. The assumption of low alertness was further substantiated by higher fatigue ratings by the chamber crew compared to those of the control group. Analysis of the continuous EEG recordings revealed that only two subjects produced reliable alpha wave activity (8-12 Hz) over Pz and, to a much smaller extent, Fz-theta wave activity (5-7 Hz) during task performance. In both subjects Pz-alpha power decreased consistently under task conditions involving single-task and dual-task tracking. Fz-theta activity was increased more by single-task and dual-task memory search than by single-task tracking. The alpha attenuation appears

  17. A Fatigue Management System for Sustained Military Operations

    National Research Council Canada - National Science Library

    Storm, William F

    2008-01-01

    .... The findings demonstrated significant decrements in cognitive performance when suddenly awakened while sleeping under the influence of zolpidem but not melatonin, Performance and polysomnography...

  18. Human Computer Music Performance

    OpenAIRE

    Dannenberg, Roger B.

    2012-01-01

    Human Computer Music Performance (HCMP) is the study of music performance by live human performers and real-time computer-based performers. One goal of HCMP is to create a highly autonomous artificial performer that can fill the role of a human, especially in a popular music setting. This will require advances in automated music listening and understanding, new representations for music, techniques for music synchronization, real-time human-computer communication, music generation, sound synt...

  19. Repeated Sprint Ability in Elite Water Polo Players and Swimmers and its Relationship to Aerobic and Anaerobic Performance

    Directory of Open Access Journals (Sweden)

    Yoav Meckel

    2013-12-01

    Full Text Available The purpose of this study was to determine indices of swimming repeated sprint ability (RSA in 19 elite water polo players compared to 16 elite swimmers during a repeated sprint swimming test (RST, and to examine the relationships between these indices and aerobic and anaerobic performance capabilities in both groups. Indices of RSA were determined by the ideal sprint time (IS, the total sprint time (TS, and the performance decrement (PD recorded during an 8 x 15-m swimming RST. Single long - (800-m and short-(25-m distance swim tests were used to determined indices of aerobic and anaerobic swimming capabilities, respectively. The water polo players exhibited lower RSA swimming indices, as well as lower scores in the single short and long swim distances, compared to the swimmers. Significant relationships were found between the 25- m swim results and the IS and the TS, but not the PD of both the swimmers and the water polo players. No significant relationships were found between the 800-m swim results and any of the RSA indices in either the swimmers or the water polo players. No significant relationships were found between the 25-m and the 800-m swim results in either the swimmers or the water polo players. The results indicate that swimmers posses better RSA as well as higher anaerobic and aerobic capabilities, as reflected by the single short- and long-distance swim tests, compared to water polo players. The results also indicate that, as for running and cycling, repeated sprint swim performance is strongly related to single sprint performance.

  20. Relationships between maximal strength of lower limb, anthropometric characteristics and fundamental explosive performance in handball players.

    Science.gov (United States)

    Hermassi, Souhail; Chelly, Mohamed Souhaiel; Wagner, Herbert; Fieseler, Georg; Schulze, Stephan; Delank, Karl-Stefan; Shephard, Roy J; Schwesig, René

    2018-02-14

     The purpose of this study was to examine relationships between lower body muscular strength, anthropometric characteristics and several measures of explosive performance in elite team-handball players.  22 male elite team-handball players (age: 19.1 ± 1.7 years) were studied during the competitive season. Standard anthropometric and body composition measures included body mass index, lower limb and thigh muscle volume, and body fat percentage. Maximal leg strength was determined by a one-repetition maximum (1-RM) half back-squat. Vertical jump performance was assessed using a squat jump (SJ) and a counter movement jump (CMJ). Repeated shuttle-sprint ability (RSA) was tested by 6 (2 × 15 m) shuttle sprints with 20 s of active recovery intervals. The best time in a single shuttle sprint (30m; RSA best ), fastest total time (RSA TT ) and RSA test performance decrement (RSA dec ) were recorded. Agility was measured using a modified T-half test (MAT). Throwing velocities of jump shooting and 3-step throwing were recorded by digital video camera.  The explained variance of 1-RM half-back-squats ranged from 0.2 % (RSA% Fatigue Index) to 70.1 % (CMJ). Four out of 8 variables (RSA Best Time, CMJ, SJ, throwing velocity of jump shoot) demonstrated an r 2  > 0.5. Jump performances seemed closely related to 1-RM half-back-squats. Furthermore, 1-RM half-back-squats were positively correlated with leg and thigh muscle volumes (r = 0.652, r = 0.768).  The anthropometric characteristics and some physical performance tests are closely related to the maximal strength performance of handball players. Coaches should focus on maximal strength training programs for the lower limbs when seeking improvements in the throwing velocity and jump performance of handball players. © Georg Thieme Verlag KG Stuttgart · New York.

  1. Effects of in-season short-term aerobic and high-intensity interval training program on repeated sprint ability and jump performance in handball players.

    Science.gov (United States)

    Hermassi, Souhail; Ingebrigtsen, Jørgen; Schwesig, René; Fieseler, Georg; Delank, Karl-Stefan; Chamari, Karim; Shephard, Roy J; Chelly, Mohamed-Souhaiel

    2018-01-01

    This study examined the effects of a 7-week in-season aerobic and high-intensity interval-training program on performance tests linked to successful handball play (e.g., repeated sprint and jumping ability). Thirty participants (age 17.0±1.2 years, body mass 81.1±3.4 kg, height 1.82±0.07 m) performed a Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1), a squat (SJ) and a Countermovement Jump Test (CMJ), as well as a repeated Sprint Ability Test (RSA). From this, maximal aerobic speed (MAS, reached at the end of the Yo-Yo IR1), jumping ability, best time in a single sprint trial (RSAbest), total time (RSATT) and the performance decrement (RSAdec) during all sprints were calculated. Later, subjects were randomly assigned to a control group (CG; N.=15) performing their normal training schedule (5 weekly sessions of ~90 minutes of handball training) or an experimental group (EG; N.=15). The EG performed two 30 min sessions per week of high-intensity aerobic exercises at 100-130% of MAS in addition to their normal training schedule. A significant improvement in MAS (d=4.1), RSAbest (d=1.9), RSATT (d=1.5) and RSAdec (d=2.3) after the training period was demonstrated. Also, significant interaction effects (time x group) were found for all parameters as the EG significantly improved performances in all tests after training. The greatest interaction effects were observed in MAS (η2=0.811) and CMJ (η2=0.759). No relevant changes in test performances were found in the CG (mean d=-0.02). These results indicate that individually speed-controlled aerobic and interval training is effective for improving specific handball performance.

  2. Body mass index predicts selected physical fitness attributes but is not associated with performance on military relevant tasks in U.S. Army Soldiers.

    Science.gov (United States)

    Pierce, Joseph R; DeGroot, David W; Grier, Tyson L; Hauret, Keith G; Nindl, Bradley C; East, Whitfield B; McGurk, Michael S; Jones, Bruce H

    2017-11-01

    Army body composition standards are based upon validated criteria; however, certain field-expedient methodologies (e.g., weight-for-height, body mass index [BMI]) may disqualify individuals from service who may otherwise excel on physical performance and military-relevant tasks. The purpose was to assess soldier physical performance and military-specific task/fitness performance stratified by BMI. Cross-sectional observational study. Male (n=275) and female (n=46) soldiers performed a wide-array of physical fitness tests and military-specific tasks, including the Army physical fitness test (APFT). Within-sex performance data were analyzed by BMI tertile stratification or by Army Body Composition Program (ABCP) weight-for-height (calculated BMI) screening standards using ANOVA/Tukey post-hoc or independent t-tests, respectively. BMI stratification (higher vs. lower BMI) was associated with significant improvements in muscular strength and power, but also with decrements in speed/agility in male and female soldiers. Within the military specific tasks, a higher BMI was associated with an increased APFT 2-Mile Run time; however, performance on a 1600-m Loaded March or a Warrior Task and Battle Drill obstacle course was not related to BMI in either sex. Male and Female soldiers who did not meet ABCP screening standards demonstrated a slower 2-Mile Run time; however, not meeting the ABCP BMI standard only affected a minimal number (∼6%) of soldiers' ability to pass the APFT. Military body composition standards require a careful balance between physical performance, health, and military readiness. Allowances should be considered where tradeoffs exist between body composition classifications and performance on physical tasks with high military relevance. Published by Elsevier Ltd.

  3. Exposure to Cooking Fumes and Acute Reversible Decrement in Lung Functional Capacity

    Directory of Open Access Journals (Sweden)

    Masoud Neghab

    2017-10-01

    Full Text Available Background: Being exposed to cooking fumes, kitchen workers are occupationally at risk of multiple respiratory hazards. No conclusive evidence exists as to whether occupational exposure to these fumes is associated with acute and chronic pulmonary effects and symptoms of respiratory diseases. Objective: To quantify the exposure levels and evaluate possible chronic and acute pulmonary effects associated with exposure to cooking fumes. Methods: In this cross-sectional study, 60 kitchen workers exposed to cooking fumes and 60 unexposed employees were investigated. The prevalence of respiratory symptoms among these groups was determined through completion of a standard questionnaire. Pulmonary function parameters were also measured before and after participants' work shift. Moreover, air samples were collected and analyzed to quantify their aldehyde, particle, and volatile organic contents. Results: The mean airborne concentrations of formaldehyde, acetaldehyde, and acrolein was 0.45 (SD 0.41, 0.13 (0.1, and 1.56 (0.41 mg/m3, respectively. The mean atmospheric concentrations of PM1, PM2.5, PM7, PM10, and total volatile organic compounds (TVOCs was 3.31 (2.6, 12.21 (5.9, 44.16 (16.6, 57 (21.55 μg/m3, and 1.31 (1.11 mg/m3, respectively. All respiratory symptoms were significantly (p<0.05 more prevalent in exposed group. No significant difference was noted between the pre-shift mean of spirometry parameters of exposed and unexposed group. However, exposed workers showed cross-shift decrease in most spirometry parameters, significantly lower than the pre-shift values and those of the comparison group. Conclusion: Exposure to cooking fumes is associated with a significant increase in the prevalence of respiratory symptoms as well as acute reversible decrease in lung functional capacity.

  4. Silicosis and lung function decrements among female ceramic workers in Italy.

    Science.gov (United States)

    Forastiere, Francesco; Goldsmith, David F; Sperati, Alessandra; Rapiti, Elisabetta; Miceli, Maria; Cavariani, Fulvio; Perucci, Carlo A

    2002-11-01

    It is well known that male ceramic workers have elevated risks of chronic silicosis. The objective of this study was to assess whether female ceramic workers also have an increased risk of silicosis and whether these women have decreased lung function related to silica exposure. Ceramic workers from Civitacastellana, Italy, were enrolled in health surveillance during the 1970s. A total of 642 women were under surveillance; a respiratory monitoring program was conducted from 1974 to 1987, with follow-up through 1991 that included annual chest radiography and measurement of lung function. Radiography findings were defined as silicosis if the chest films were > or =1/0 with small, rounded opacities. Multiple linear regression models for repeated measures (generalized estimating equations) were run to evaluate associations of forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV(1)) with years of exposure and radiograph opacities. Nine cases of silicosis were identified on the basis of radiographic evidence. Silicosis risk was not associated with smoking but was related to employment before 1970 and demonstrated a dose-response gradient for years of exposure. FVC and FEV(1) both showed significant (p associations with duration of exposure and with positive radiography findings. The results for female ceramic workers are consistent with those for male employees regarding exposure to fibrogenic dusts.

  5. Exposure to Cooking Fumes and Acute Reversible Decrement in Lung Functional Capacity.

    Science.gov (United States)

    Neghab, Masoud; Delikhoon, Mahdieh; Norouzian Baghani, Abbas; Hassanzadeh, Jafar

    2017-10-01

    Being exposed to cooking fumes, kitchen workers are occupationally at risk of multiple respiratory hazards. No conclusive evidence exists as to whether occupational exposure to these fumes is associated with acute and chronic pulmonary effects and symptoms of respiratory diseases. To quantify the exposure levels and evaluate possible chronic and acute pulmonary effects associated with exposure to cooking fumes. In this cross-sectional study, 60 kitchen workers exposed to cooking fumes and 60 unexposed employees were investigated. The prevalence of respiratory symptoms among these groups was determined through completion of a standard questionnaire. Pulmonary function parameters were also measured before and after participants' work shift. Moreover, air samples were collected and analyzed to quantify their aldehyde, particle, and volatile organic contents. The mean airborne concentrations of formaldehyde, acetaldehyde, and acrolein was 0.45 (SD 0.41), 0.13 (0.1), and 1.56 (0.41) mg/m 3 , respectively. The mean atmospheric concentrations of PM 1 , PM 2.5 , PM 7 , PM 10 , and total volatile organic compounds (TVOCs) was 3.31 (2.6), 12.21 (5.9), 44.16 (16.6), 57 (21.55) μg/m 3 , and 1.31 (1.11) mg/m 3 , respectively. All respiratory symptoms were significantly (pcooking fumes is associated with a significant increase in the prevalence of respiratory symptoms as well as acute reversible decrease in lung functional capacity.

  6. Cognitive Assessment and Prediction to Promote Individualized Capability Augmentation and Reduce Decrement (CAPT PICARD), Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA missions include long periods of low workload followed by sudden high-tempo operations, a pattern that can be detrimental to situational awareness and...

  7. Rotor-System Log-Decrement Identification Using Short-Time Fourier-Transform Filter

    Directory of Open Access Journals (Sweden)

    Qihang Li

    2015-01-01

    Full Text Available With the increase of the centrifugal compressor capability, such as large scale LNG and CO2 reinjection, the stability margin evaluation is crucial to assure the compressor work in the designed operating conditions in field. Improving the precision of parameter identification of stability is essential and necessary as well. Based on the time-varying characteristics of response vibration during the sine-swept process, a short-time Fourier transform (STFT filter was introduced to increase the signal-noise ratio and improve the accuracy of the estimated stability parameters. A finite element model was established to simulate the sine-swept process, and the simulated vibration signals were used to study the filtering effect and demonstrate the feasibility to identify the stability parameters by using Multiple-Input and Multiple-Output system identification method that combines the prediction error method and instrumental variable method. Simulation results show that the identification method with STFT filter improves the estimated accuracy much well and makes the curves of frequency response function clearer. Experiment was carried out on a test rig as well, which indicates the identification method is feasible in stability identification, and the results of experiment indicate that STFT filter works very well.

  8. Decrement of postprandial insulin secretion determines the progressive nature of type-2 diabetes.

    Science.gov (United States)

    Shim, Wan Sub; Kim, Soo Kyung; Kim, Hae Jin; Kang, Eun Seok; Ahn, Chul Woo; Lim, Sung Kil; Lee, Hyun Chul; Cha, Bong Soo

    2006-10-01

    Type-2 diabetes is a progressive disease. However, little is known about whether decreased fasting or postprandial pancreatic beta-cell responsiveness is more prominent with increased duration of diabetes. The aim of this study was to evaluate the relationship between insulin secretion both during fasting and 2 h postprandial, and the duration of diabetes in type-2 diabetic patients. Cross-sectional clinical investigation. We conducted a meal tolerance test in 1466 type-2 diabetic patients and calculated fasting (M0) and postprandial (M1) beta-cell responsiveness. The fasting C-peptide, postprandial C-peptide, M0, and M1 values were lower, but HbA1c values were higher, in patients with diabetes duration > 10 years than those in other groups. There was no difference in the HbA1c levels according to the tertiles of their fasting C-peptide level. However, in a group of patients with highest postprandial C-peptide tertile, the HbA1c values were significantly lower than those in other groups. After adjustment of age, sex, and body mass index (BMI), the duration of diabetes was found to be negatively correlated with fasting C-peptide (gamma = -0.102), postprandial C-peptide (gamma = -0.356), M0 (gamma = -0.263), and M1 (gamma = -0.315; P multiple regression analysis, M0, M1, and homeostasis model assessment for insulin resistance (HOMA-IR) emerged as predictors of HbAlc after adjustment for age, sex, and BMI (R2 = 0.272, 0.080, and 0.056 respectively). With increasing duration of diabetes, the decrease of postprandial insulin secretion is becoming more prominent, and postprandial beta-cell responsiveness may be a more important determinant for glycemic control than fasting beta-cell responsiveness.

  9. Multiple-Decrement Compositional Forecasting with the Lee-Carter Model

    OpenAIRE

    Guan, Tianyu

    2014-01-01

    Changes in cause of death patterns have a great impact on health and social care costs paid by government and insurance companies. Unfortunately an overwhelming majority of methods for mortality projections is based on overall mortality with only very few studies focusing on forecasting cause-specific mortality. In this project, our aim is to forecast cause-specific death density with a coherent model. Since cause-specific death density obeys a unit sum constraint, it can be considered as com...

  10. Rotor-System Log-Decrement Identification Using Short-Time Fourier-Transform Filter

    OpenAIRE

    Li, Qihang; Wang, Weimin; Chen, Lifang; Sun, Dan

    2015-01-01

    With the increase of the centrifugal compressor capability, such as large scale LNG and CO2 reinjection, the stability margin evaluation is crucial to assure the compressor work in the designed operating conditions in field. Improving the precision of parameter identification of stability is essential and necessary as well. Based on the time-varying characteristics of response vibration during the sine-swept process, a short-time Fourier transform (STFT) filter was introduced to increase the ...

  11. Muscle contractility decrement and correlated morphology during the pathogenesis of streptozotocin-diabetic mice.

    Science.gov (United States)

    Fahim, M A; el-Sabban, F; Davidson, N

    1998-06-01

    Peripheral neuropathy of both motor and sensory nerves has been well documented in diabetes mellitus, but the evidence for physiological and correlated morphological changes during the pathogenesis of myopathy is scarce. In the present report, we have chosen the dorsiflexor muscle of adult male mice as a model for studying in situ muscle contraction and neuromuscular ultrastructure during the pathogenesis of streptozotocin-induced diabetes. Thirty mice (30 g bodyweight) were injected once i.p. with streptozotocin solution (200 mg/Kg) to induce experimental diabetes mellitus. Comparative analyses of in situ muscle isometric contractile characteristics were studied (at 1 Hz, 5 Hz and 30 Hz nerve stimulation) in urethane-anesthetized (2 mg/g, i.p.) control and diabetic mice at three time points, 2 weeks, 4 weeks, and 8 weeks postinjection. Synaptic delay was also recorded in diabetic and age-matched control mice. There was a significant increase in synaptic delay in both 4-week and 8-week diabetic mice compared with control mice (8.9 +/- 1.2 msec and 7.6 +/- 0.6 msec, respectively, compared with 6.1 +/- 0.5 msec). At all three stimulation frequencies, diabetes did not affect muscle contractile speed but significantly reduced the twitch tension after 8 weeks, with no changes at 2 weeks or 4 weeks. The recorded single-twitch tension values were 2.6 +/- 0.3 g, 2.1 +/- 0.6 g, 2.2 +/- 0.7 g, and 1.2 +/- 0.1 g for control, 2 weeks, 4 weeks, and 8 weeks, respectively. At 30 Hz, the recorded tension values were 4.6 +/- 1.6 g, 3.1 +/- 1.2 g, 3.1 +/- 1.1 g, and 2.1 +/- 1.0 g for control, 2 weeks, 4 weeks, and 8 weeks, respectively. Ultrastructural changes in neuromuscular junctions were similar to those that have been described in disuse and aging. These changes were observed after 8 weeks and included serve loss of synaptic vesicles, electron-dense bodies, and myelin-like figures as well as degeneration of mitochondria. The results reveal that streptozotocin-induced diabetes affects presynaptically the neuromuscular junction as well as muscle itself. Actions at both sites may contribute to the functional alterations seen in muscle contractile properties and may play a role in the pathogenesis of diabetic neuromyopathy.

  12. Aerobic Exercise Decreases Lung Inflammation by IgE Decrement in an OVA Mice Model.

    Science.gov (United States)

    Camargo Hizume-Kunzler, Deborah; Greiffo, Flavia R; Fortkamp, Bárbara; Ribeiro Freitas, Gabriel; Keller Nascimento, Juliana; Regina Bruggemann, Thayse; Melo Avila, Leonardo; Perini, Adenir; Bobinski, Franciane; Duarte Silva, Morgana; Rocha Lapa, Fernanda; Paula Vieira, Rodolfo; Vargas Horewicz, Verônica; Soares Dos Santos, Adair Roberto; Cattelan Bonorino, Kelly

    2017-06-01

    Aerobic exercise (AE) reduces lung function decline and risk of exacerbations in asthmatic patients. However, the inflammatory lung response involved in exercise during the sensitization remains unclear. Therefore, we evaluated the effects of exercise for 2 weeks in an experimental model of sensitization and single ovalbumin-challenge. Mice were divided into 4 groups: mice non-sensitized and not submitted to exercise (Sedentary, n=10); mice non-sensitized and submitted to exercise (Exercise, n=10); mice sensitized and exposed to ovalbumin (OVA, n=10); and mice sensitized, submitted to exercise and exposed to OVA (OVA+Exercise, n=10). 24 h after the OVA/saline exposure, we counted inflammatory cells from bronchoalveolar fluid (BALF), lung levels of total IgE, IL-4, IL-5, IL-10 and IL-1ra, measurements of OVA-specific IgG1 and IgE, and VEGF and NOS-2 expression via western blotting. AE reduced cell counts from BALF in the OVA group (p<0.05), total IgE, IL-4 and IL-5 lung levels and OVA-specific IgE and IgG1 titers (p<0.05). There was an increase of NOS-2 expression, IL-10 and IL-1ra lung levels in the OVA groups (p<0.05). Our results showed that AE attenuated the acute lung inflammation, suggesting immunomodulatory properties on the sensitization process in the early phases of antigen presentation in asthma. © Georg Thieme Verlag KG Stuttgart · New York.

  13. Decrement of GABAA receptor-mediated inhibitory postsynaptic currents in dentate granule cells in epileptic hippocampus.

    Science.gov (United States)

    Isokawa, M

    1996-05-01

    1. Inhibitory postsynaptic currents (IPSCs) were studied in hippocampal dentate granule cells (DGCs) in the pilocarpine model and human temporal lobe epilepsy, with the use of the whole cell patch-clamp recording technique in slice preparations. 2. In the pilocarpine model, hippocampal slices were prepared from rats that were allowed to experience spontaneous seizures for 2 mo. Human hippocampal specimens were obtained from epileptic patients who underwent surgical treatment for medically intractable seizures. 3. IPSCs were generated by single perforant path stimulation and recorded at a membrane potential (Vm) of 0 mV near the reversal potential of glutamate excitatory postsynaptic currents in the voltage-clamp recording. IPSCs were pharmacologically identified as gamma-aminobutyric acid-A (GABAA) IPSCs by 10 microM bicuculline methiodide. 4. During low-frequency stimulation, IPSCs were not different in amplitude among non-seizure-experienced rat hippocampi, human nonsclerotic hippocampi, seizure-experienced rat hippocampi, and human sclerotic hippocampi. In the last two groups of DGCs, current-clamp recordings indicated the presence of prolonged excitatory postsynaptic potentials (EPSPs) mediated by the N-methyl-D-aspartate (NMDA) receptor. 5. High-frequency stimulation, administered at Vm = -30 mV to activate NMDA currents, reduced GABAA IPSC amplitude specifically in seizure-experienced rat hippocampi (t = 2.5, P < 0.03) and human sclerotic hippocampi (t = 7.7, P < 0.01). This reduction was blocked by an NMDA receptor antagonist, 2-amino-5-phosphonovaleric acid (APV) (50 microM). The time for GABAA IPSCs to recover to their original amplitude was also shortened by the application of APV. 6. I conclude that, when intensively activated, NMDA receptor-mediated excitatory transmission may interact with GABAergic synaptic inhibition in DGCs in seizure-experienced hippocampus to transiently reduce GABA(A) receptor-channel function. Such interactions may contribute to give rise to epileptic excitation in chronically seizure-prone hippocampus.

  14. Real option valuation of a decremental regulation service provided by electricity storage.

    Science.gov (United States)

    Szabó, Dávid Zoltán; Martyr, Randall

    2017-08-13

    This paper is a quantitative study of a reserve contract for real-time balancing of a power system. Under this contract, the owner of a storage device, such as a battery, helps smooth fluctuations in electricity demand and supply by using the device to increase electricity consumption. The battery owner must be able to provide immediate physical cover, and should therefore have sufficient storage available in the battery before entering the contract. Accordingly, the following problem can be formulated for the battery owner: determine the optimal time to enter the contract and, if necessary, the optimal time to discharge electricity before entering the contract. This problem is formulated as one of optimal stopping, and is solved explicitly in terms of the model parameters and instantaneous values of the power system imbalance. The optimal operational strategies thus obtained ensure that the battery owner has positive expected economic profit from the contract. Furthermore, they provide explicit conditions under which the optimal discharge time is consistent with the overall objective of power system balancing. This paper also carries out a preliminary investigation of the 'lifetime value' aggregated from an infinite sequence of these balancing reserve contracts. This lifetime value, which can be viewed as a single project valuation of the battery, is shown to be positive and bounded. Therefore, in the long run such reserve contracts can be beneficial to commercial operators of electricity storage, while reducing some of the financial and operational risks in power system balancing.This article is part of the themed issue 'Energy management: flexibility, risk and optimization'. © 2017 The Author(s).

  15. The peculiar balmer decrement of SN 2009ip: Constraints on circumstellar geometry

    Energy Technology Data Exchange (ETDEWEB)

    Levesque, Emily M.; Stringfellow, Guy S.; Bally, John; Keeney, Brian A. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado 389-UCB, Boulder, CO 80309 (United States); Ginsburg, Adam G., E-mail: Emily.Levesque@colorado.edu [European Southern Observatory, ESO Headquarters, Karl-Schwarzschild-Strasse 2, D-95748 Garching bei München (Germany)

    2014-01-01

    We present optical and near-IR spectroscopic observations of the luminous blue variable SN 2009ip during its remarkable photometric evolution of 2012. The spectra sample three key points in the SN 2009ip light curve, corresponding to its initial brightening in August (2012-A) and its dramatic rebrightening in early October (2012-B). Based on line fluxes and velocities measured in our spectra, we find a surprisingly low I(Hα)/I(Hβ) ratio (∼1.3-1.4) in the 2012-B spectra. Such a ratio implies either a rare Case B recombination scenario where Hα, but not Hβ, is optically thick, or an extremely high density for the circumstellar material of n{sub e} > 10{sup 13} cm{sup –3}. The Hα line intensity yields a minimum radiating surface area of ≳20,000 AU{sup 2} in Hα at the peak of SN 2009ip's photometric evolution. Combined with the nature of this object's spectral evolution in 2012, a high circumstellar density and large radiating surface area imply the presence of a thin disk geometry around the central star (and, consequently, a possible binary companion), suggesting that the observed 2012-B rebrightening of SN 2009ip can be attributed to the illumination of the disk's inner rim by fast-moving ejecta produced by the underlying events of 2012-A.

  16. Effect of stimulus intensity on latent inhibition: A case for generalization decrement

    Directory of Open Access Journals (Sweden)

    Gabriel Rodríguez

    2002-01-01

    Full Text Available En dos experimentos se empleó la técnica de aversión condicionada al sabor en ratas para examinar el efecto de la intensidad del estímulo expuesto sobre la inhibición latente. En el Experimento 1 se valoró el efecto de la exposición de un sabor dulce en distintas concentraciones sobre la tasa de adquisición de su condicionamiento posterior. Los resultados de este experimento mostraron un mayor efecto de inhibición latente tras la exposición del sabor en igual concentración a la empleada durante el condicionamiento (grupo EI que tras su exposición en una concentración mayor (grupo EM o menor (grupo Em. Además, esta atenuación del efecto de inhibición latente en las condiciones de cambio en la concentración resultó menor en el grupo EM que en el grupo Em. El Experimento 2 demostró que la generalización de las propiedades aversivas condicionadas al sabor fue mayor entre las concentraciones empleadas en el grupo EM que en el grupo Em. Estos resultados sugieren que el aparente efecto de la intensidad del estímulo en la inhibición latente podría ser explicado en términos de decremento en la generalización.

  17. Fast detection of unexpected sound intensity decrements as revealed by human evoked potentials.

    Directory of Open Access Journals (Sweden)

    Heike Althen

    Full Text Available The detection of deviant sounds is a crucial function of the auditory system and is reflected by the automatically elicited mismatch negativity (MMN, an auditory evoked potential at 100 to 250 ms from stimulus onset. It has recently been shown that rarely occurring frequency and location deviants in an oddball paradigm trigger a more negative response than standard sounds at very early latencies in the middle latency response of the human auditory evoked potential. This fast and early ability of the auditory system is corroborated by the finding of neurons in the animal auditory cortex and subcortical structures, which restore their adapted responsiveness to standard sounds, when a rare change in a sound feature occurs. In this study, we investigated whether the detection of intensity deviants is also reflected at shorter latencies than those of the MMN. Auditory evoked potentials in response to click sounds were analyzed regarding the auditory brain stem response, the middle latency response (MLR and the MMN. Rare stimuli with a lower intensity level than standard stimuli elicited (in addition to an MMN a more negative potential in the MLR at the transition from the Na to the Pa component at circa 24 ms from stimulus onset. This finding, together with the studies about frequency and location changes, suggests that the early automatic detection of deviant sounds in an oddball paradigm is a general property of the auditory system.

  18. Retardation and summation tests after extinction: The role of familiarity and generalization decrement

    Directory of Open Access Journals (Sweden)

    Luis Aguado

    2004-01-01

    Full Text Available Pruebas de retraso y sumación después de la extinción: El papel de la familiaridad y el decremento de generalización. En cuatro experimentos de aversión al sabor con ratas se compararon los efectos de estímulos extinguidos o preexpuestos en las pruebas de retraso y de sumación. El Experimento 1 mostró que cuando el grado de exposición al sabor crítico es igual en todas las condiciones, la adquisición tras la preexposición y la readquisición después de la extinción se producen con la misma tasa y más lentamente que la adquisición en una condición de control con un estímulo nuevo. En el Experimento 2, la readquisición 2 días después de la extinción fue, de nuevo, más lenta que la adquisición con un nuevo estímulo, pero este retraso desapareció cuando mediaba un intervalo de 21 días entre la extinción y la readquisición. El Experimento 3 mostró que un sabor extinguido y otro preexpuesto producen un efecto de sumación comparable, atenuando por igual la aversión a un sabor previamente condicionado. Finalmente, el Experimento 4 mostró que una atenuación similar de la aversión es producida también por un estímulo nuevo. Estos resultados sugieren, primero, que el retraso de la adquisición observado con un sabor extinguido podría deberse a la inhibición latente producida por la experiencia repetida con el sabor durante la extinción y, segundo, que la atenuación de la aversión a un excitador en la prueba de sumación podría reflejar decremento de la generalización y no un proceso específico de aprendizaje.

  19. Electrophysiological Evidence for Adult Age-Related Sparing and Decrements in Emotion Perception and Attention

    Directory of Open Access Journals (Sweden)

    Joshua W. Pollock

    2012-08-01

    Full Text Available The present study examined adult age differences in processing emotional faces using a psychological refractory period (PRP paradigm. We used both behavioral and event-related potential (P1 component measures. Task 1 was tone discrimination (fuzzy vs. pure tones and Task 2 was emotional facial discrimination (happy vs. angry faces. The stimulus onset asynchrony (SOA between the two tasks was 100 ms, 300 ms, and 900 ms. Earlier research observed age deficits in emotional facial discrimination for negative (angry than for positive (happy faces (Baena et al., 2010. Thus, we predicted that older adults would show decreased attentional efficiency in carrying out dual-task processing on the P1 (a component linked to amygdalar modulation of visual perception; Rotshtein et al., 2010. Both younger and older groups showed significantly higher P1 amplitudes at 100- and 300-ms SOAs than at the 900-ms SOA, and this suggests that both age groups could process Task 2 emotions without central attention. Also, younger adults showed significantly higher P1 activations for angry than for happy faces, but older adults showed no difference. These results are consistent with the idea that younger adults exhibited amygdalar modulation of visual perception, but that older adults did not.

  20. A New Approach for Predicting the Variance of Random Decrement Functions

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune

    mean Gaussian distributed processes the RD functions are proportional to the correlation functions of the processes. If a linear structur is loaded by Gaussian white noise the modal parameters can be extracted from the correlation funtions of the response, only. One of the weaknesses of the RD...... technique is that no consistent approach to estimate the variance of the RD functions is known. Only approximate relations are available, which can only be used under special conditions. The variance of teh RD functions contains valuable information about accuracy of the estimates. Furthermore, the variance...... can be used as basis for a decision about how many time lags from the RD funtions should be used in the modal parameter extraction procedure. This paper suggests a new method for estimating the variance of the RD functions. The method is consistent in the sense that the accuracy of the approach...

  1. A New Approach for Predicting the Variance of Random Decrement Functions

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune

    1998-01-01

    mean Gaussian distributed processes the RD functions are proportional to the correlation functions of the processes. If a linear structur is loaded by Gaussian white noise the modal parameters can be extracted from the correlation funtions of the response, only. One of the weaknesses of the RD...... technique is that no consistent approach to estimate the variance of the RD functions is known. Only approximate relations are available, which can only be used under special conditions. The variance of teh RD functions contains valuable information about accuracy of the estimates. Furthermore, the variance...... can be used as basis for a decision about how many time lags from the RD funtions should be used in the modal parameter extraction procedure. This paper suggests a new method for estimating the variance of the RD functions. The method is consistent in the sense that the accuracy of the approach...

  2. Cognitive Assessment and Prediction to Promote Individualized Capability Augmentation and Reduce Decrement (CAPT PICARD), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Manned NASA missions include long periods of low workload, followed by sudden, high tempo operations. This can be detrimental to situational awareness and...

  3. Estimation of the Coefficient of Restitution of Rocking Systems by the Random Decrement Technique

    DEFF Research Database (Denmark)

    Brincker, Rune; Demosthenous, M.; Manos, G. C.

    The aim of this paper is to investigate the possibility of estimating an average damping parameter for a rocking system due to impact, the so-called coefficient of restitution, from the random response, i.e. when the loads are random and unknown, and the response is measured. The objective is to ...... of freedom system loaded by white noise, estimating the coefficient of restitution as explained, and comparing the estimates with the value used in the simulations. Several estimates for the coefficient of restitution are considered, and reasonable results are achieved....

  4. How Stress Treatments Influence the Performance of Biodegradable Poly(Butylene Succinate-Based Copolymers with Thioether Linkages for Food Packaging Applications

    Directory of Open Access Journals (Sweden)

    Valentina Siracusa

    2017-08-01

    Full Text Available Biodegradable poly(butylene succinate (PBS-based random copolymers containing thioether linkages (P(BSxTDGSy of various compositions have been investigated and characterized from the gas barrier, thermal, and mechanical point of view, after food contact simulants or thermal and photoaging processes. Each stress treatment was performed on thin films and the results obtained have been compared to the same untreated film, used as a standard. Barrier properties with different gases (O2 and CO2 were evaluated, showing that the polymer chemical composition strongly influenced the permeability behavior. The relationships between the diffusion coefficients (D and solubility (S with polymer composition were also investigated. The results highlighted a correlation between polymer chemical structure and treatment. Gas transmission rate (GTR mainly depending on the performed treatment, as GTR increased with the increase of TDGS co-unit amount. Thermal and mechanical tests allowed for the recording of variations in the degree of crystallinity and in the tensile properties. An increase in the crystallinity degree was recorded after contact with simulant liquids and aging treatments, together with a molecular weight decrease, a slight enhancement of the elastic modulus and a decrement of the elongation at break, proportional to the TDGS co-unit content.

  5. How Stress Treatments Influence the Performance of Biodegradable Poly(Butylene Succinate)-Based Copolymers with Thioether Linkages for Food Packaging Applications.

    Science.gov (United States)

    Siracusa, Valentina; Genovese, Laura; Munari, Andrea; Lotti, Nadia

    2017-08-30

    Biodegradable poly(butylene succinate) (PBS)-based random copolymers containing thioether linkages (P(BSxTDGSy)) of various compositions have been investigated and characterized from the gas barrier, thermal, and mechanical point of view, after food contact simulants or thermal and photoaging processes. Each stress treatment was performed on thin films and the results obtained have been compared to the same untreated film, used as a standard. Barrier properties with different gases (O₂ and CO₂) were evaluated, showing that the polymer chemical composition strongly influenced the permeability behavior. The relationships between the diffusion coefficients ( D ) and solubility ( S ) with polymer composition were also investigated. The results highlighted a correlation between polymer chemical structure and treatment. Gas transmission rate ( GTR ) mainly depending on the performed treatment, as GTR increased with the increase of TDGS co-unit amount. Thermal and mechanical tests allowed for the recording of variations in the degree of crystallinity and in the tensile properties. An increase in the crystallinity degree was recorded after contact with simulant liquids and aging treatments, together with a molecular weight decrease, a slight enhancement of the elastic modulus and a decrement of the elongation at break, proportional to the TDGS co-unit content.

  6. Pavement Subgrade Performance Study

    DEFF Research Database (Denmark)

    Zhang, Wei; Ullidtz, Per; Macdonald, Robin

    1998-01-01

    The report describes the second test in the Danish Road Testing Machine (RTM) under the International Pavement Subgrade Performance Study. Pavement response was measured in different layers, and compared to different theroretical values. Performance in terms of plastic strains, rutting...

  7. Developing Effective Performance Measures

    Science.gov (United States)

    2014-10-14

    University When Performance Measurement Goes Bad Laziness Vanity Narcissism Too Many Pettiness Inanity 52 Developing Effective...Kasunic, October 14, 2014 © 2014 Carnegie Mellon University Narcissism Measuring performance from the organization’s point of view, rather than from

  8. Performance SNAPSHOT Reports

    Data.gov (United States)

    Department of Housing and Urban Development — The HOME Program Performance SNAPSHOTs are quarterly cumulative performance reports, which can be useful in tracking the HOME program progress of participating...

  9. Winter maintenance performance measure.

    Science.gov (United States)

    2016-01-01

    The Winter Performance Index is a method of quantifying winter storm events and the DOTs response to them. : It is a valuable tool for evaluating the States maintenance practices, performing post-storm analysis, training : maintenance personnel...

  10. Tracker Performance Metric

    National Research Council Canada - National Science Library

    Olson, Teresa; Lee, Harry; Sanders, Johnnie

    2002-01-01

    .... We have developed the Tracker Performance Metric (TPM) specifically for this purpose. It was designed to measure the output performance, on a frame-by-frame basis, using its output position and quality...

  11. HOPWA Performance Profiles

    Data.gov (United States)

    Department of Housing and Urban Development — HOPWA Performance Profiles are generated quarterly for all agencies receiving HOPWA formula or competitive grants. Performance Profiles are available at the national...

  12. R high performance programming

    CERN Document Server

    Lim, Aloysius

    2015-01-01

    This book is for programmers and developers who want to improve the performance of their R programs by making them run faster with large data sets or who are trying to solve a pesky performance problem.

  13. Mapping Intermediality in Performance

    NARCIS (Netherlands)

    2010-01-01

    Mapping Intermediality in Performance benadert het vraagstuk van intermedialiteit met betrekking tot performance (vooral theater) vanuit vijf verschillende invalshoeken: performativiteit en lichaam; tijd en ruimte; digitale cultuur en posthumanisme; netwerken; pedagogiek en praxis. In deze boeiende

  14. Dan Performer Mei Lanfang

    DEFF Research Database (Denmark)

    Risum, Janne

    2010-01-01

    The convention of performing female characters (dan characters) in Beijing opera, as practised by its most prominent male performer of female characters Mei Lanfang, and its and his cultural context and aesthetic aim...

  15. The Effect of Two Speed Endurance Training Regimes on Performance of Soccer Players.

    Directory of Open Access Journals (Sweden)

    F Marcello Iaia

    Full Text Available In order to better understand the specificity of training adaptations, we compared the effects of two different anaerobic training regimes on various types of soccer-related exercise performances. During the last 3 weeks of the competitive season, thirteen young male professional soccer players (age 18.5±1 yr, height 179.5±6.5 cm, body mass 74.3±6.5 kg reduced the training volume by ~20% and replaced their habitual fitness conditioning work with either speed endurance production (SEP; n = 6 or speed endurance maintenance (SEM; n = 7 training, three times per wk. SEP training consisted of 6-8 reps of 20-s all-out running bouts followed by 2 min of passive recovery, whereas SEM training was characterized by 6-8 x 20-s all-out efforts interspersed with 40 s of passive recovery. SEP training reduced (p<0.01 the total time in a repeated sprint ability test (RSAt by 2.5%. SEM training improved the 200-m sprint performance (from 26.59±0.70 to 26.02±0.62 s, p<0.01 and had a likely beneficial impact on the percentage decrement score of the RSA test (from 4.07±1.28 to 3.55±1.01% but induced a very likely impairment in RSAt (from 83.81±2.37 to 84.65±2.27 s. The distance covered in the Yo-Yo Intermittent Recovery test level 2 was 10.1% (p<0.001 and 3.8% (p<0.05 higher after SEP and SEM training, respectively, with possibly greater improvements following SEP compared to SEM. No differences were observed in the 20- and 40-m sprint performances. In conclusion, these two training strategies target different determinants of soccer-related physical performance. SEP improved repeated sprint and high-intensity intermittent exercise performance, whereas SEM increased muscles' ability to maximize fatigue tolerance and maintain speed development during both repeated all-out and continuous short-duration maximal exercises. These results provide new insight into the precise nature of a stimulus necessary to improve specific types of athletic performance in

  16. Individual styles of professional operator's performance for the needs of interplanetary mission.

    Science.gov (United States)

    Boritko, Yaroslav; Gushin, Vadim; Zavalko, Irina; Smoleevskiy, Alexandr; Dudukin, Alexandr

    Maintenance of the cosmonaut’s professional performance reliability is one of the priorities of long-term space flights safety. Cosmonaut’s performance during long-term space flight decreases due to combination of the microgravity effects and inevitable degradation of skills during prolonged breaks in training. Therefore, the objective of the elaboration of countermeasures against skill decrement is very relevant. During the experiment with prolonged isolation "Mars-500" in IMBP two virtual models of professional operator’s activities were used to investigate the influence of extended isolation, monotony and confinement on professional skills degradation. One is well-known “PILOT-1” (docking to the space station), another - "VIRTU" (manned operations of planet exploration). Individual resistance to the artificial sensory conflict was estimated using computerized version of “Mirror koordinograf” with GSR registration. Two different individual performance styles, referring to the different types of response to stress, have been identified. Individual performance style, called "conservative control", manifested in permanent control of parameters, conditions and results of the operator’s activity. Operators with this performance style demonstrate high reliability in performing tasks. The drawback of the style is intensive resource expenditure - both the operator (physiological "cost") and the technical system operated (fuel, time). This style is more efficient while executing tasks that require long work with high reliability required according to a detailed protocol, such as orbital flight. Individual style, called "exploratory ", manifested in the search of new ways of task fulfillment. This style is accompanied by partial, periodic lack of control of the conditions and result of operator’s activity due to flexible approach to the tasks perfect implementation. Operators spent less resource (fuel, time, lower physiological "cost") due to high self

  17. Performance measurement and pay for performance

    NARCIS (Netherlands)

    Tuijl, van H.F.J.M.; Kleingeld, P.A.M.; Algera, J.A.; Rutten, M.L.; Sonnentag, S.

    2002-01-01

    This chapter, which takes a (re)design perspective, focuses on the management of employees’ contributions to organisational goal attainment. The control loop for the self-regulation of task performance is used as a frame of reference. Several subsets of design requirements are described and related

  18. Managing the "Performance" in Performance Management.

    Science.gov (United States)

    Repinski, Marilyn; Bartsch, Maryjo

    1996-01-01

    Describes a five-step approach to performance management which includes (1) redefining tasks; (2) identifying skills; (3) determining what development tools are necessary; (4) prioritizing skills development; and (5) developing an action plan. Presents a hiring model that includes job analysis, job description, selection, goal setting, evaluation,…

  19. NU Performance/NO Performance? / Keiu Virro

    Index Scriptorium Estoniae

    Virro, Keiu, 1987-

    2009-01-01

    3. "NU Performance'i" festivalist "Recycle Pop" Kanuti gildis 11.-14. novembrini 2009. Kuraatorid Anders Härm ja Priit Raud. Erkki Luugi, Lotte Jürjendali ja Katrin Ratte, Kiwa, Andres Lõo ning ExTRAfINE ehk Marko Laimre, Kati Ilvese, Killu Sukmiti ja Raul Kelleri esinemisest

  20. Nutrition and Mental Performance

    Science.gov (United States)

    Stein, Zena; And Others

    1972-01-01

    Prenatal exposure to the Dutch famine of 1944-45 had no detectable effects on the adult mental performance of surviving male offspring; birth weight was not related to mental performance; and the association of social class with mental performance was strong. (AL)

  1. Relationships and Predictive Capabilities of Jump Assessments to Soccer-Specific Field Test Performance in Division I Collegiate Players.

    Science.gov (United States)

    Lockie, Robert G; Stage, Alyssa A; Stokes, John J; Orjalo, Ashley J; Davis, DeShaun L; Giuliano, Dominic V; Moreno, Matthew R; Risso, Fabrice G; Lazar, Adrina; Birmingham-Babauta, Samantha A; Tomita, Tricia M

    2016-12-03

    Leg power is an important characteristic for soccer, and jump tests can measure this capacity. Limited research has analyzed relationships between jumping and soccer-specific field test performance in collegiate male players. Nineteen Division I players completed tests of: leg power (vertical jump (VJ), standing broad jump (SBJ), left- and right-leg triple hop (TH)); linear (30 m sprint; 0⁻5 m, 5⁻10 m, 0⁻10, 0⁻30 m intervals) and change-of-direction (505) speed; soccer-specific fitness (Yo-Yo Intermittent Recovery Test Level 2); and 7 × 30-m sprints to measure repeated-sprint ability (RSA; total time (TT), performance decrement (PD)). Pearson's correlations ( r ) determined jump and field test relationships; stepwise regression ascertained jump predictors of the tests ( p jumps correlated with the 0⁻5, 0⁻10, and 0⁻30 m sprint intervals ( r = -0.65⁻-0.90). VJ, SBJ, and left- and right-leg TH correlated with RSA TT ( r = -0.51⁻-0.59). Right-leg TH predicted the 0⁻5 and 0⁻10 m intervals (R² = 0.55⁻0.81); the VJ predicted the 0⁻30 m interval and RSA TT (R² = 0.41⁻0.84). Between-leg TH asymmetry correlated with and predicted left-leg 505 and RSA PD ( r = -0.68⁻0.62; R² = 0.39⁻0.46). Improvements in jumping ability could contribute to faster speed and RSA performance in collegiate soccer players.

  2. Muscle function, physical performance and body composition changes in men with prostate cancer undergoing androgen deprivation therapy

    Institute of Scientific and Technical Information of China (English)

    Thomas W Storer; Renee Miciek; Thomas G Travison

    2012-01-01

    Prostate cancer (PCa) is the most common visceral malignancy in men with androgen deprivation therapy (ADT) the preferred therapy to suppress testosterone production and hence tumor growth.Despite its effectiveness in lowering testosterone,ADT is associated with side effects including loss of muscle mass,diminished muscle strength,decrements in physical performance,earlier fatigue and declining quality of life.This review reports a survey of the literature with a focus on changes in muscle strength,physical function and body composition,due to short-term and long-term ADT.Studies in these areas are sparse,especially well-controlled,prospective randomized trials.Cross-sectional and longitudinal data (up to 2 years) for men with PCa treated with ADT as well as patients with PCa not receiving ADT and age-matched healthy men are presented when available.Based on limited longitudinal data,the adverse effects of ADT on muscle function,physical performance and body composition occur shortly after the onset of ADT andtend to persist and worsen over time.Exercise training is a safe and effective intervention for mitigating these changes and initial guidelines for exercise program design for men with PCa have been published by the American College of Sports Medicine.Disparities in study duration,typos of studies and other patient-specific variables such as time since diagnosis,cancer stage and comorbidities may all affect an understanding of the influence of ADT on health,physical performance and mortality.

  3. Relationships and Predictive Capabilities of Jump Assessments to Soccer-Specific Field Test Performance in Division I Collegiate Players

    Directory of Open Access Journals (Sweden)

    Robert G. Lockie

    2016-12-01

    Full Text Available Leg power is an important characteristic for soccer, and jump tests can measure this capacity. Limited research has analyzed relationships between jumping and soccer-specific field test performance in collegiate male players. Nineteen Division I players completed tests of: leg power (vertical jump (VJ, standing broad jump (SBJ, left- and right-leg triple hop (TH; linear (30 m sprint; 0–5 m, 5–10 m, 0–10, 0–30 m intervals and change-of-direction (505 speed; soccer-specific fitness (Yo-Yo Intermittent Recovery Test Level 2; and 7 × 30-m sprints to measure repeated-sprint ability (RSA; total time (TT, performance decrement (PD. Pearson’s correlations (r determined jump and field test relationships; stepwise regression ascertained jump predictors of the tests (p < 0.05. All jumps correlated with the 0–5, 0–10, and 0–30 m sprint intervals (r = −0.65–−0.90. VJ, SBJ, and left- and right-leg TH correlated with RSA TT (r = −0.51–−0.59. Right-leg TH predicted the 0–5 and 0–10 m intervals (R2 = 0.55–0.81; the VJ predicted the 0–30 m interval and RSA TT (R2 = 0.41–0.84. Between-leg TH asymmetry correlated with and predicted left-leg 505 and RSA PD (r = −0.68–0.62; R2 = 0.39–0.46. Improvements in jumping ability could contribute to faster speed and RSA performance in collegiate soccer players.

  4. Performance in Public Organizations

    DEFF Research Database (Denmark)

    Andersen, Lotte Bøgh; Boesen, Andreas; Pedersen, Lene Holm

    2016-01-01

    of management and performance are classified. The results illustrate how a systematization of the conceptual space of performance in public organizations can help researchers select what to study and what to leave out with greater accuracy while also bringing greater clarity to public debates about performance.......Performance in public organizations is a key concept that requires clarification. Based on a conceptual review of research published in 10 public administration journals, this article proposes six distinctions to describe the systematic differences in performance criteria: From which stakeholder...

  5. Danish mutual fund performance

    DEFF Research Database (Denmark)

    Christensen, Michael

    2013-01-01

    This article provides the first independent performance analysis of Danish mutual funds. We analyse selectivity and market timing abilities for 71 mutual funds that have been in operation from 2001 to 2010. The results show great fund performance diversity. Half the funds have performed neutrally......, whereas 42% of the funds have shown significantly negative performance and only 7% of the funds have over-performed their benchmark. Furthermore, 14% of the funds analysed possess market timing abilities, but for 8 out of 10 funds, their market timing ability has been unsuccessful....

  6. Performer rights and responsibilities in historical performance

    Directory of Open Access Journals (Sweden)

    Irving John

    2014-01-01

    Full Text Available In April 2014, fortepianist and Mozart specialist John Irving recorded a CD of solo keyboard sonatas by Joseph Haydn, using a modern copy of a Viennese fortepiano of Haydn’s era. This is an account of the project written from the performer’s perspective, examining some relevant issues of historical performance practice, organology, and detailed reflections upon the performer’s preparations (of various musical and technical kinds for the recording.

  7. Performance Measurement und Environmental Performance Measurement

    OpenAIRE

    Sturm, Anke

    2000-01-01

    Die Zielsetzung der vorliegenden Dissertationsschrift besteht in der Entwicklung einer systematisierten Vorgehensweise, eines Controllingmodells, zur unternehmensinternen Umweltleistungsmessung. Das entwickelte Environmental Performance Measurement (EPM)-Modell umfaßt die fünf Stufen Festlegung der Ziele der Umweltleistungsmessung (1. Stufe), Erfassung der Umwelteinflüsse nach der ökologischen Erfolgsspaltung (2. Stufe), Bewertung der Umwelteinflüsse auf der Grundlage des qualitätszielbezogen...

  8. Predictive performance models and multiple task performance

    Science.gov (United States)

    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.

  9. Walking while performing working memory tasks changes the prefrontal cortex hemodynamic activations and gait kinematics

    Directory of Open Access Journals (Sweden)

    Ming-I Brandon Lin

    2016-05-01

    Full Text Available BackgroundIncreasing evidence suggests that walking while performing a concurrent task negatively influences gait performance. However, it remains unclear how higher-level cognitive processes and coordination of limb movements are altered in challenging walking environments. This study investigated the influence of cognitive task complexity and walking road condition on the neutral correlates of executive function and postural control in dual-task walking. MethodsTwenty-four healthy young adults completed a series of overground walks with three walking road conditions (wide, narrow, with obstacles with and without the concurrent n-back working memory tasks of two complexity levels (1-back and 3-back. Prefrontal brain activation was assessed by functional near-infrared spectroscopy. A three-dimensional motion analysis system was used simultaneously to measure gait performance and lower-extremity kinematics. Repeated measures analysis of variance were performed to examine the differences between the conditions. ResultsIn comparison with standing still, participants showed lower n-back task accuracy while walking, with the worst performance from the road with obstacles. Spatiotemporal gait parameters, lower-extremity joint movements, and the relative changes in oxygenated hemoglobin (HbO concentration levels were all significantly different across the task complexity and walking path conditions. While dual-tasking participants were found to flex their hips and knees less, leading to a slower gait speed, longer stride time, shorter step length, and greater gait variability than during normal walking. For narrow-road walking, smaller ankle dorsiflexion and larger hip flexion were observed, along with a reduced gait speed. Obstacle negotiation was mainly characterized by increased gait variability than other conditions. HbO levels appeared to be lower during dual-task walking than normal walking. Compared to wide and obstacle conditions, walking on

  10. Understanding the Effects of Long-duration Space Flight on Astronant Functional Task Performance

    Science.gov (United States)

    Bloomberg, Jacob J.; Batson, Crystal D.; Buxton, Roxanne E.; Feiveson, Al H.; Kofman, Igor S.; Lee, Stuart M. C.; Miller, Chris A.; Mulavara, Ajitkumar P.; Peters, Brian T.; Phillips, Tiffany; hide

    2014-01-01

    Space flight is known to cause alterations in multiple physiological systems including changes in sensorimotor, cardiovascular, and neuromuscular systems. These physiological changes cause balance, gait and visual disturbances, cardiovascular deconditioning, and loss of muscle mass and strength. These changes may affect a crewmember's ability to perform critical mission tasks immediately after landing on a planetary surface. To understand how changes in physiological function affect functional performance, an interdisciplinary pre- and postflight testing regimen, Functional Task Test (FTT), was developed to systematically evaluate both astronaut functional performance and related physiological changes. Ultimately this information will be used to assess performance risks and inform the design of countermeasures for exploration class missions. We are currently conducting the FTT study on International Space Station (ISS) crewmembers before and after 6-month expeditions. Additionally, in a corresponding study we are using the FTT protocol on subjects before and after 70 days of 6deg head-down bed-rest as an analog for space flight. Bed-rest provides the opportunity for us to investigate the role of prolonged axial body unloading in isolation from the other physiological effects produced by exposure to the microgravity environment of space flight. Therefore, the bed rest analog allows us to investigate the impact of body unloading on both functional tasks and on the underlying physiological factors that lead to decrement in performance and then compare them with the results obtained in our space flight study. Functional tests included ladder climbing, hatch opening, jump down, manual manipulation of objects and tool use, seat egress and obstacle avoidance, recovery from a fall and object translation tasks. Physiological measures included assessments of postural and gait control, dynamic visual acuity, fine motor control, plasma volume, heart rate, blood pressure

  11. TEACHER PERFORMANCE EVALUATION

    Directory of Open Access Journals (Sweden)

    Guadalupe Iván Martínez-Chairez

    2015-07-01

    Full Text Available This research report comes from a study that was developed during the school years 2013-2014, 2014-2015, in the southern state of Chihuahua central region, in the education sector 25 consisting of five school zones that provide services to Meoqui municipalities, Julimes and Delicias. The study is a mixed court, correlational comprehensive sequential procedure. Some of the results is that there is a correlation between the 578 years of service of teachers and the score assigned to students in teaching career, but there is no association between teacher performance and the context in which it works, in addition there is no relationship between the teacher performance and school performance of students on standardized tests. 2.4% of the representative sample presented an excellent teacher performance, 7.3% have a bad teacher performance, but it is noteworthy that 39% of teachers observed lies with good teaching performance.

  12. Performing "the Other"

    DEFF Research Database (Denmark)

    Riis, Helle Bach

    2013-01-01

    A group of youngsters perform their self-composed rap lyrics on stage in the Betty Nansen Theater in Copenhagen. The theater claims, that the performance portraits the youngsters as they truly are – as opposed to the medias portrayal. The play is part of an integration project, co-financed by the......A group of youngsters perform their self-composed rap lyrics on stage in the Betty Nansen Theater in Copenhagen. The theater claims, that the performance portraits the youngsters as they truly are – as opposed to the medias portrayal. The play is part of an integration project, co......-financed by the Danish Ministry of Integration. This essay presents a critical analysis of the representation of the youngsters on stage. The analysis is especially based on the concepts of performance and performativity and on hip-hop as a genre framework for the representation....

  13. Sound perception, performance

    CERN Document Server

    2013-01-01

    Musical Performance covers many aspects like Musical Acoustics, Music Psychology, or motor and prosodic actions. It deals with basic concepts of the origin or music and its evolution, ranges over neurocognitive foundations, and covers computational, technological, or simulation solutions. This volume gives an overview about current research in the foundation of musical performance studies on all these levels. Recent concepts of synchronized systems, evolutionary concepts, basic understanding of performance as Gestalt patterns, theories of chill as performance goals or historical aspects are covered. The neurocognitive basis of motor action in terms of music, musical syntax, as well as therapeutic aspects are discussed. State-of-the-art applications in performance realizations, like virtual room acoustics, virtual musicians, new concepts of real-time physical modeling using complex performance data as input or sensor and gesture studies with soft- and hardware solutions are presented. So although the field is ...

  14. High performance homes

    DEFF Research Database (Denmark)

    Beim, Anne; Vibæk, Kasper Sánchez

    2014-01-01

    Can prefabrication contribute to the development of high performance homes? To answer this question, this chapter defines high performance in more broadly inclusive terms, acknowledging the technical, architectural, social and economic conditions under which energy consumption and production occur....... Consideration of all these factors is a precondition for a truly integrated practice and as this chapter demonstrates, innovative project delivery methods founded on the manufacturing of prefabricated buildings contribute to the production of high performance homes that are cost effective to construct, energy...

  15. PERFORMANCE - AN EVOLVING CONCEPT

    OpenAIRE

    Assist. Mirela-Oana Pintea Ph.D Student; Lect. Monica-Violeta Achim

    2010-01-01

    The concept of performance is a problematic concept and will remain so as long as the definition of company performance varies depending on the interests of users of information. On this consideration, no consensus was reached regarding the definition, methodology and performance models used. Defining this concept is realized in accordance with its objectives of users of information, while the methodology and models used are influenced by legal regulations and management policies. The approac...

  16. Bruce A - performance power

    Energy Technology Data Exchange (ETDEWEB)

    Boucher, P. [Bruce Power, Tiverton, ON (Canada)

    2015-07-01

    This paper discusses the strategy for improving performance at Bruce Power. The key to excellence is changing behaviours. Reinforcing and enforcing expectations, aligned with the 2015 operating to the Highest Standards Site Initiative. Long term equipment strategies, supported by the 2015 Equipment Health Site Initiative, individual and group accountability for online/outage Work Management, with further gains through 2015 Maintenance Alignment and Resource Strategy (MARS) Site Initiative. Results showed human performance improvement, more reliable and predictable units and outage performance improvement.

  17. Extending Critical Performativity

    DEFF Research Database (Denmark)

    Spicer, André; Alvesson, Mats; Kärreman, Dan

    2016-01-01

    In this article we extend the debate about critical performativity. We begin by outlining the basic tenets of critical performativity and how this has been applied in the study of management and organization. We then address recent critiques of critical performance. We note these arguments suffer...... of public importance; engaging with non-academic groups using dialectical reasoning; scaling up insights through movement building; and propagating deliberation...

  18. Collaboration in Performing Arts

    OpenAIRE

    Langeveld, Cees; Belme, D.; Koppenberg, T.

    2014-01-01

    markdownabstract__Abstract__ As a result of declining government support, performing arts organisations (PAOs) face increased challenges and difficulties in the sector. They attempt to develop new ways of generating income and seek new models of organising the production and presentation of performing arts. Hereby, we can think of collaboration and integration as horizontal and vertical within the production chain of performing arts. There are various reasons for cultural organisations to dec...

  19. Performance Analysis of MYSEA

    Science.gov (United States)

    2012-09-01

    Services FSD Federated Services Daemon I&A Identification and Authentication IKE Internet Key Exchange KPI Key Performance Indicator LAN Local Area...spection takes place in different processes in the server architecture. Key Performance Indica- tor ( KPI )s associated with the system need to be...application and risk analysis of security controls. Thus, measurement of the KPIs is needed before an informed tradeoff between the performance penalties

  20. Performance of Patenting Firms

    DEFF Research Database (Denmark)

    Madsen, Erik Strøjer; Smith, Valdemar; Nielsen, Anders Østergaard

    2000-01-01

    Most countries focus on industries with high technology and the governments grant subsidies to innovating firms. However, there has been remarkable few studies of the performance of innovative firms or industries. This study examines the performance of patent active firms compared to the non-patenting...... firms within the manufacturing sector in Denmark. Performance is measured both by growth in employment as well as in the return on equity and profit share in turnover. The results suggest that differences in performance of patenting and non-patenting firms are very small, which questions the political...

  1. Process of performance assessment

    International Nuclear Information System (INIS)

    King, C.M.; Halford, D.K.

    1987-01-01

    Performance assessment is the process used to evaluate the environmental consequences of disposal of radioactive waste in the biosphere. An introductory review of the subject is presented. Emphasis is placed on the process of performance assessment from the standpoint of defining the process. Performance assessment, from evolving experience at DOE sites, has short-term and long-term subprograms, the components of which are discussed. The role of mathematical modeling in performance assessment is addressed including the pros and cons of current approaches. Finally, the system/site/technology issues as the focal point of this symposium are reviewed

  2. Safety performance indicators program

    International Nuclear Information System (INIS)

    Vidal, Patricia G.

    2004-01-01

    In 1997 the Nuclear Regulatory Authority (ARN) initiated a program to define and implement a Safety Performance Indicators System for the two operating nuclear power plants, Atucha I and Embalse. The objective of the program was to incorporate a set of safety performance indicators to be used as a new regulatory tool providing an additional view of the operational performance of the nuclear power plants, improving the ability to detect degradation on safety related areas. A set of twenty-four safety performance indicators was developed and improved throughout pilot implementation initiated in July 1998. This paper summarises the program development, the main criteria applied in each stage and the results obtained. (author)

  3. COGNITIVE PERFORMANCE LABORATORY

    Data.gov (United States)

    Federal Laboratory Consortium — This laboratory conducts basic and applied human research studies to characterize cognitive performance as influenced by militarily-relevant contextual and physical...

  4. Benchmarking and Performance Management

    Directory of Open Access Journals (Sweden)

    Adrian TANTAU

    2010-12-01

    Full Text Available The relevance of the chosen topic is explained by the meaning of the firm efficiency concept - the firm efficiency means the revealed performance (how well the firm performs in the actual market environment given the basic characteristics of the firms and their markets that are expected to drive their profitability (firm size, market power etc.. This complex and relative performance could be due to such things as product innovation, management quality, work organization, some other factors can be a cause even if they are not directly observed by the researcher. The critical need for the management individuals/group to continuously improve their firm/company’s efficiency and effectiveness, the need for the managers to know which are the success factors and the competitiveness determinants determine consequently, what performance measures are most critical in determining their firm’s overall success. Benchmarking, when done properly, can accurately identify both successful companies and the underlying reasons for their success. Innovation and benchmarking firm level performance are critical interdependent activities. Firm level variables, used to infer performance, are often interdependent due to operational reasons. Hence, the managers need to take the dependencies among these variables into account when forecasting and benchmarking performance. This paper studies firm level performance using financial ratio and other type of profitability measures. It uses econometric models to describe and then propose a method to forecast and benchmark performance.

  5. Board Task Performance

    DEFF Research Database (Denmark)

    Minichilli, Alessandro; Zattoni, Alessandro; Nielsen, Sabina

    2012-01-01

    identify three board processes as micro-level determinants of board effectiveness. Specifically, we focus on effort norms, cognitive conflicts and the use of knowledge and skills as determinants of board control and advisory task performance. Further, we consider how two different institutional settings....... The findings show that: (i) Board processes have a larger potential than demographic variables to explain board task performance; (ii) board task performance differs significantly between boards operating in different contexts; and (iii) national context moderates the relationships between board processes...... and board task performance....

  6. Performance Confirmation Plan

    International Nuclear Information System (INIS)

    Lindner, E.N.

    2000-01-01

    As described, the purpose of the Performance Confirmation Plan is to specify monitoring, testing, and analysis activities for evaluating the accuracy and adequacy of the information used to determine that performance objectives for postclosure will be met. This plan defines a number of specific performance confirmation activities and associated test concepts in support of the MGR that will be implemented to fulfill this purpose. In doing so, the plan defines an approach to identify key factors and processes, predict performance, establish tolerances and test criteria, collect data (through monitoring, testing, and experiments), analyze these data, and recommend appropriate action. The process of defining which factors to address under performance confirmation incorporates input from several areas. In all cases, key performance confirmation factors are those factors which are: (1) important to safety, (2) measurable and predictable, and (3) relevant to the program (i.e., a factor that is affected by construction, emplacement, or is a time-dependent variable). For the present version of the plan, performance confirmation factors important to safety are identified using the principal factors from the RSS (CRWMS M and O 2000a) (which is derived from TSPA analyses) together with other available performance assessment analyses. With this basis, key performance confirmation factors have been identified, and test concepts and test descriptions have been developed in the plan. Other activities are also incorporated into the performance confirmation program outside of these key factors. Additional activities and tests have been incorporated when they are prescribed by requirements and regulations or are necessary to address data needs and model validation requirements relevant to postclosure safety. These other activities have been included with identified factors to construct the overall performance confirmation program

  7. Performance Confirmation Plan

    International Nuclear Information System (INIS)

    Lindner, E.N.

    2000-01-01

    As described, the purpose of the Performance Confirmation Plan is to specify monitoring, testing, and analysis activities for evaluating the accuracy and adequacy of the information used to determine that performance objectives for postclosure will be met. This plan defines a number of specific performance confirmation activities and associated test concepts in support of the MGR that will be implemented to fulfill this purpose. In doing so, the plan defines an approach to identify key factors and processes, predict performance, establish tolerances and test criteria, collect data (through monitoring, testing, and experiments), analyze these data, and recommend appropriate action. The process of defining which factors to address under performance confirmation incorporates input from several areas. In all cases, key performance confirmation factors are those factors which are: (1) important to safety, (2) measurable and predictable, and (3) relevant to the program (i.e., a factor that i s affected by construction, emplacement, or is a time-dependent variable). For the present version of the plan, performance confirmation factors important to safety are identified using the principal factors from the RSS (CRWMS M and O 2000a) (which is derived from TSPA analyses) together with other available performance assessment analyses. With this basis, key performance confirmation factors have been identified, and test concepts and test descriptions have been developed in the plan. Other activities are also incorporated into the performance confirmation program outside of these key factors. Additional activities and tests have been incorporated when they are prescribed by requirements and regulations or are necessary to address data needs and model validation requirements relevant to postclosure safety. These other activities have been included with identified factors to construct the overall performance confirmation program

  8. Conducting effective performance appraisals.

    Science.gov (United States)

    2001-01-01

    According to experts, performance appraisals rate just below firing someone as the least favorite thing managers do. Many factors contribute to this view--one is that current systems do a poor job of evaluating performance and in fact often impede both evaluation and performance. When used as part of an ongoing supportive process of goal setting and feedback, performance appraisals can enhance performance and morale. One alternative to traditional employee evaluation methods is full-circle or 360-degree feedback. Contained in this issue are practical suggestions for preparing employees for performance appraisals which, when followed daily, encourage employees to put their best feet forward as part of their regular routine. Also included is a template specific to assessing the performance of clinical laboratory technologists . Additionally, numerous resources are provided to help you refine appraisal systems to fit your needs. Full-circle feedback is proving to be a boon to managers. It relieves them from being the exclusive "heavies" in evaluating performance, integrates appraisal input from several sources, and incorporates increasing employee skills, competencies, and satisfaction, thus improving productivity of people and processes. And aren't integration and continuous improvement what the laboratory is all about?

  9. The Performability Manager

    NARCIS (Netherlands)

    Franken, Leonard J.N.; Haverkort, Boudewijn R.H.M.

    1994-01-01

    The authors describe the performability manager, a distributed system component that contributes to a more effective and efficient use of system components and prevents quality of service (QoS) degradation. The performability manager dynamically reconfigures distributed systems whenever needed, to

  10. Respirator field performance factors

    International Nuclear Information System (INIS)

    Skaggs, B.J.; DeField, J.D.; Strandberg, S.W.; Sutcliffe, C.R.

    1985-01-01

    The Industrial Hygiene Group assisted OSHA and the NRC in measurements of respirator performance under field conditions. They reviewed problems associated with sampling aerosols within the respirator in order to determine fit factors (FFs) or field performance factor (FPF). In addition, they designed an environmental chamber study to determine the effects of temperature and humidity on a respirator wearer

  11. Whither Performance Contracting?

    Science.gov (United States)

    Green, Norman S.

    This report describes briefly performance contracts; discusses their shortcomings, pitfalls, and advantages; and gives some insight into the future development of this new concept. Two shortcomings of performance contracting include (1) teaching to the test and (2) board abdication of its responsibility for making final decisions about educational…

  12. Marketization and Economic Performance

    DEFF Research Database (Denmark)

    Hansen, Morten Balle

    2010-01-01

    . A reform enforcing compulsory competitive tendering in homecare for elderly people in Denmark is analysed and its relation to measures of economic performance is explored. Two competing models of marketization are contrasted in the analysis: a problem solving model inspired by public choice ideology...... little impact on economic performance is found, which lends support to an institutional interpretation of the findings....

  13. Key performance indicators

    NARCIS (Netherlands)

    Zwetsloot, G.I.J.M.

    2014-01-01

    This paper addresses how organisations can use OSH performance indicators. This is an important way to mainstream OSH into business management. Key performance indicators (KPIs) should provide objective data on the OSH situation. It is often said that ‘what gets measured gets managed’. Without

  14. Thermal Inertia Performance Evaluation of Light-Weighted Construction Space Envelopes Using Phase Change Materials in Mexico City’s Climate

    Directory of Open Access Journals (Sweden)

    Adriana Lira-Oliver

    2017-10-01

    Full Text Available The present study’s main objective was to determine the applicability of organic phase change materials (PCMs in a building’s envelope construction system for the passive provision of comfortable indoor thermal conditions over one year based on thermal inertia in Mexico City. Research on PCMs relate mainly to their use in building envelope construction systems to reduce energy consumption for mechanical indoor thermal conditioning—not in passive systems. Computer simulation results of mean indoor temperature variations are presented with the objective of evaluating these construction systems’ thermal inertia properties. In the present study, dynamic thermal simulations (DTS, using EnergyPlus software, of ten 1 m3 test units with envelope construction systems combining organic PCMs of different fusion temperatures with conventional materials were performed. Based on the results, it is concluded that the implementation of organic PCMs with a fusion temperature around 25 °C in combination with aerated concrete in a space envelope results in the highest number of hours the indoor temperatures remain within the comfort range throughout a typical year, due to the decrement of indoor temperature oscillations and, to a large extent, to thermal lag.

  15. The Effects of a Multi-Ingredient Performance Supplement on Hormonal Profiles and Body Composition in Male College Athletes

    Directory of Open Access Journals (Sweden)

    Matthew H. Sharp

    2016-05-01

    Full Text Available Periods of intense training can elicit an acute decline in performance and body composition associated with weakened hormone profiles. This study investigated the effects of a multi-ingredient performance supplement (MIPS on body composition and hormone levels in college athletes following a six-week training protocol. Twenty male college athletes were equally assigned to MIPS and placebo (PLA groups for supplementation (three pills, twice daily in conjunction with resistance training and specialized sports training (e.g., nine total sessions/week for six weeks. Dual Energy X-ray Absorptiometry determined body composition at weeks 0 and 6. Serum samples collected at weeks 0 and 6 determined free testosterone (FT, total testosterone (TT, IGF-1 and total estrogen (TE levels. PLA experienced a significant decline in lean body mass (LBM (−1.5 kg; p < 0.05 whereas the MIPS sustained LBM. The MIPS increased TT 21.9% (541.5 ± 48.7 to 639.1 ± 31.7 and increased FT 15.2% (13.28 ± 1.1 to 15.45 ± 1.3 ng/dL (p < 0.05. Conversely, PLA decreased TT 7.9% (554.5 ± 43.3 to 497.2 ± 39.1 ng/dL, decreased FT 17.4% (13.41 ± 1.8 to 11.23 ± 2.55 ng/dL, and decreased FT:E 12.06% (p < 0.05. These findings suggest the MIPS can prevent decrements in LBM and anabolic hormone profiles during intense training periods.

  16. Design method of high performance precast external walls for warm climate by multi-objective optimization analysis

    International Nuclear Information System (INIS)

    Baglivo, Cristina; Congedo, Paolo Maria

    2015-01-01

    Taking into account the global environmental problems, there is the urgent need to reduce energy consumption and the greenhouse gas emissions in the construction sector. Environmental awareness can be achieved through the extensive application of precast systems in buildings construction. A multi-criteria analysis has been used to obtain energy-efficient precast walls for Zero Energy Building in warm climate focusing on eco-friendly building materials. The modeFRONTIER optimization tool, with the use of computational procedures developed in Matlab, has been used to assess the thermal dynamics of building components. The optimization has been carried out in terms of steady thermal transmittance, periodic thermal transmittance, decrement factor, time shift, areal heat capacity, thermal admittance, surface mass, small thickness, eco sustainability score, light-weight and costs. The best sequences of layers show repetitive features: high surface mass for the first layer (internal side), followed by eco-friendly insulating materials for the middle layer and common insulating materials for the outer layer. The results illustrate that it is possible to obtain high performance precast multi-layered walls also with light and thin solutions; in particular, the superficial mass and the internal areal heat capacity have an important role to obtain the best performance in the warm climate. - Highlights: • Environmental awareness through the application of prefabrication systems. • The precast allows important benefits compared to traditional walls build in situ. • At the end of their useful life, the precast can be re-used. • Precast walls with very high efficiency for warm climates. • High internal areal heat capacity avoids events of overheating/cooling down.

  17. NRC performance assessment program

    International Nuclear Information System (INIS)

    Coplan, S.M.

    1986-01-01

    The U.S. Nuclear Regulatory Commission's (NRC) performance assessment program includes the development of guidance to the U.S. Department of Energy (DOE) on preparation of a license application and on conducting the studies to support a license application. The nature of the licensing requirements of 10 CFR Part 60 create a need for performance assessments by the DOE. The NRC and DOE staffs each have specific roles in assuring the adequacy of those assessments. Performance allocation is an approach for determining what testing and analysis will be needed during site characterization to assure that an adequate data base is available to support the necessary performance assessments. From the standpoint of establishing is implementable methodology, the most challenging performance assessment needed for licensing is the one that will be used to determine compliance with the U.S. Environmental Protection Agency's (EPA) containment requirement

  18. High Performance Marine Vessels

    CERN Document Server

    Yun, Liang

    2012-01-01

    High Performance Marine Vessels (HPMVs) range from the Fast Ferries to the latest high speed Navy Craft, including competition power boats and hydroplanes, hydrofoils, hovercraft, catamarans and other multi-hull craft. High Performance Marine Vessels covers the main concepts of HPMVs and discusses historical background, design features, services that have been successful and not so successful, and some sample data of the range of HPMVs to date. Included is a comparison of all HPMVs craft and the differences between them and descriptions of performance (hydrodynamics and aerodynamics). Readers will find a comprehensive overview of the design, development and building of HPMVs. In summary, this book: Focuses on technology at the aero-marine interface Covers the full range of high performance marine vessel concepts Explains the historical development of various HPMVs Discusses ferries, racing and pleasure craft, as well as utility and military missions High Performance Marine Vessels is an ideal book for student...

  19. Performance Aided Design

    DEFF Research Database (Denmark)

    Parigi, Dario

    2014-01-01

    paradigm where the increasing integration of parametric tools and performative analysis is changing the way we learn and design. The term Performance Aided Architectural Design (PAD) is proposed at the Master of Science of Architecture and Design at Aalborg University, with the aim of extending a tectonic...... tradition of architecture with computational tools, preparing the basis for the creation of the figure of a modern master builder, sitting at the boundary of the disciplines of architecture and engineering. Performance Aided Design focuses on the role of performative analysis, embedded tectonics......, and computational methods tools to trigger creativity and innovative understanding of relation between form material and a increasingly wide range of performances in architectural design. The ultimate goal is to pursue a design approach that aims at embracing rather than excluding the complexity implicit...

  20. Performing the Super Instrument

    DEFF Research Database (Denmark)

    Kallionpaa, Maria

    2016-01-01

    can empower performers by producing super instrument works that allow the concert instrument to become an ensemble controlled by a single player. The existing instrumental skills of the performer can be multiplied and the qualities of regular acoustic instruments extended or modified. Such a situation......The genre of contemporary classical music has seen significant innovation and research related to new super, hyper, and hybrid instruments, which opens up a vast palette of expressive potential. An increasing number of composers, performers, instrument designers, engineers, and computer programmers...... have become interested in different ways of “supersizing” acoustic instruments in order to open up previously-unheard instrumental sounds. Super instruments vary a great deal but each has a transformative effect on the identity and performance practice of the performing musician. Furthermore, composers...

  1. Implementering & Performative Potentialer

    DEFF Research Database (Denmark)

    Damkjer, Annemarie

    organizational boundaries. Furthermore, the analysis reflect how specific modes of ordering in the local process of implementation perform and displace the technology of performance management. The study provides an alternative view of the performative potentials in implementation processes and specifically...... challenge the traditional models of implementation. It is suggested, that we view implementation practices as performative in relation to the co-configuration of technology and organizational practices and that both the co-configurative perspective and the materiality of implementation practices is included......This thesis investigates how technology is constituted as an object of implementation. Using the theoretical lens of actor-network theory the thesis investigates how the technology of performance management becomes a matter of implementation in the Danish Defence and how the technology...

  2. Professional performance in school

    Directory of Open Access Journals (Sweden)

    Rubio, J. F.

    2012-01-01

    Full Text Available Professional performance in education is now calling the attention of researcher due to its role in the professionalizing process intended to increase international education standards. In this article the term professional performance is examined from the two socio-historic traditional roles involved in training the individuals as a bio-psychic and social entity: teachers and executive. By means of scientific methods, the author gives the theoretical grounds connecting professional performance, learning and individual capacity of using them in solving problem at his labor position. The professional performance is regarded as a human value that stimulates the activity. By predicting educational alternatives, the paper portraits a model of professional performance in education, referring the necessary actions needed for achieving the goals of education. Searching and discussing such alternatives leads to reinterpret professional problems and to find out ways of improving educational standards.

  3. PerformAge

    DEFF Research Database (Denmark)

    Fristrup, Tine

    2012-01-01

    are constituted as experts on aging. In the humanistic model of aging, the aging self becomes the expert on the process of becoming of age. Thi sconflicting aspect of the discursive battlefield on aging will be elaborated in the framework of PerformAge and understood as a temporal and spatial theorising of aging......: the poetics of aging. Making the lived experience the centrepiece of this paper, poetic representations of aging lives (Laurel Richardson, 1991, 1992) will articulate subjectively felt experiences in social encounters between people performing age. In writing the social (Dorothy E. Smith, 1999) encounters, I...... as a researcher perform age in the process of figuring the possible age performativities as subject positioning performativity (Judith Butler, 1995) in the social encounters and textualized in poetic representations. Inspired by the work on Reifungsromane (Barbara Frey Waxman, 1990), I do not want to paint...

  4. Long-term bridge performance high priority bridge performance issues.

    Science.gov (United States)

    2014-10-01

    Bridge performance is a multifaceted issue involving performance of materials and protective systems, : performance of individual components of the bridge, and performance of the structural system as a whole. The : Long-Term Bridge Performance (LTBP)...

  5. Relationships between the handball-specific complex test, non-specific field tests and the match performance score in elite professional handball players.

    Science.gov (United States)

    Hermassi, Souhail; Chelly, Mohamed-Souhaiel; Wollny, Rainer; Hoffmeyer, Birgit; Fieseler, Georg; Schulze, Stephan; Irlenbusch, Lars; Delank, Karl-Stefan; Shephard, Roy J; Bartels, Thomas; Schwesig, René

    2018-06-01

    This study assessed the validity of the handball-specific complex test (HBCT) and two non-specific field tests in professional elite handball athletes, using the match performance score (MPS) as the gold standard of performance. Thirteen elite male handball players (age: 27.4±4.8 years; premier German league) performed the HBCT, the Yo-Yo Intermittent Recovery (YYIR) test and a repeated shuttle sprint ability (RSA) test at the beginning of pre-season training. The RSA results were evaluated in terms of best time, total time, and fatigue decrement. Heart rates (HR) were assessed at selected times throughout all tests; the recovery HR was measured immediately post-test and 10 minutes later. The match performance score was based on various handball specific parameters (e.g., field goals, assists, steals, blocks, and technical mistakes) as seen during all matches of the immediately subsequent season (2015/2016). The parameters of run 1, run 2, and HR recovery at minutes 6 and 10 of the RSA test all showed a variance of more than 10% (range: 11-15%). However, the variance of scores for the YYIR test was much smaller (range: 1-7%). The resting HR (r2=0.18), HR recovery at minute 10 (r2=0.10), lactate concentration at rest (r2=0.17), recovery of heart rate from 0 to 10 minutes (r2=0.15), and velocity of second throw at first trial (r2=0.37) were the most valid HBCT parameters. Much effort is necessary to assess MPS and to develop valid tests. Speed and the rate of functional recovery seem the best predictors of competitive performance for elite handball players.

  6. The Efficacy of a Pre-Workout Vegan Supplement on High-Intensity Cycling Performance in Healthy College-Aged Males.

    Science.gov (United States)

    Gallien, Gabrielle; Bellar, David; Davis, Greggory R

    2017-11-02

    There is a limited supply of sport nutrition supplements currently available for vegan or vegetarian athletes. In addition, the efficacy of a vegan or vegetarian pre-workout supplement that does not contain any processed ingredients or stimulants is currently unknown. The purpose of the current study was to examine the effects of an unprocessed vegan pre-workout supplement on high-intensity cycling performance. Participants completed three separate cycling trials following the consumption of a vegan pre-workout supplement, an isocaloric processed supplement, or a zero-calorie placebo supplement. Each supplement was consumed 30 minutes prior to each trial, and each cycling trial was separated by a minimum of 72 hours. Supplements were administered using a randomized, double-blind cross-over design. Each cycling trial was performed at a workload equal to 80% VO 2peak until exhaustion. The average time in seconds (s) until exhaustion values for the vegan, isocaloric, and zero-calorie supplements were 482 ± 163, 480 ± 157, and 496 ± 238, respectively. Consumption of the vegan supplement did not significantly improve performance compared to an isocaloric and zero-calorie supplement (F = 0.12, p =.89). The results of this study indicate that individuals who choose a vegan pre-workout supplement (over an isocaloric or zero-calorie product) will not experience any acute decrements or ergogenic benefits in cycling performance. Although the present study does not support performance benefits of the tested vegan pre-workout supplement before cycling, additional research examining various exercise intensities and modalities is warranted.

  7. Investigating the Effects of Typical Rowing Strength Training Practices on Strength and Power Development and 2,000 m Rowing Performance

    Directory of Open Access Journals (Sweden)

    Ian Gee Thomas

    2016-04-01

    Full Text Available This study aimed to determine the effects of a short-term, strength training intervention, typically undertaken by club-standard rowers, on 2,000 m rowing performance and strength and power development. Twenty-eight male rowers were randomly assigned to intervention or control groups. All participants performed baseline testing involving assessments of muscle soreness, creatine kinase activity (CK, maximal voluntary contraction (leg-extensors (MVC, static-squat jumps (SSJ, counter-movement jumps (CMJ, maximal rowing power strokes (PS and a 2,000 m rowing ergometer time-trial (2,000 m with accompanying respiratory-exchange and electromyography (EMG analysis. Intervention group participants subsequently performed three identical strength training (ST sessions, in the space of five days, repeating all assessments 24 h following the final ST. The control group completed the same testing procedure but with no ST. Following ST, the intervention group experienced significant elevations in soreness and CK activity, and decrements in MVC, SSJ, CMJ and PS (p < 0.01. However, 2,000 m rowing performance, pacing strategy and gas exchange were unchanged across trials in either condition. Following ST, significant increases occurred for EMG (p < 0.05, and there were non-significant trends for decreased blood lactate and anaerobic energy liberation (p = 0.063 – 0.086. In summary, club-standard rowers, following an intensive period of strength training, maintained their 2,000 m rowing performance despite suffering symptoms of muscle damage and disruption to muscle function. This disruption likely reflected the presence of acute residual fatigue, potentially in type II muscle fibres as strength and power development were affected.

  8. Performing rurality. But who?

    Directory of Open Access Journals (Sweden)

    Dymitrow Mirek

    2017-12-01

    Full Text Available Reflective inquiries to better understand ‘the rural’ have tried to embed rural research within the notion of performativity. Performativity assumes that the capacity of language is not simply to communicate but also to consummate action, whereupon citational uses of concepts produce a series of material effects. Of late, this philosophical shift has also implicated geographers as active agents in producing, reproducing and performing rurality. This paper provides a critical evaluation of what this new insistence really means for the production of geographical knowledge. Using framework analysis as a method, the paper scrutinizes several reportedly influential papers on the topic of rural performativity. Our findings reveal that, while indeed reflexive on issues of academic integrity, methodology and ethics, performances of rurality are continuedly placed ‘out there’ amongst ‘rural people’, i.e. in a priori defined and often stereotypically understood contexts, either by way of ‘spatial delimitation’ or ‘activity delimitation’. Effectively, such testimonies provide a truncated state of fidelity, where performance- oriented reflexivity is seconded by contradictory empirics of uneven value and with few commonalities. We conclude that by turning towards performativity as an allegedly more helpful way of obtaining rural coherence, we at the same time overlook our own role in keeping ‘rural theory’ alive.

  9. Learnability and linguistic performance

    DEFF Research Database (Denmark)

    Drozd, Kenneth

    2004-01-01

    of the human biological endowment for language in the form of a UNIVERSAL GRAMMAR (UG) (Chomsky, 1965). With respect to experimental design, C&T have strongly maintained that even young children know UG constraints but perform poorly in some experiments-due to the extralinguistic demands associated...... with experimental tasks, particularly those involved in presupposition accommodation and complex response planning. C&T specifically design their experiments to reduce the impact of extralinguistic demands on children's linguistic performance while at the same time providing felicitous environments for adultlike...... performance....

  10. Java performance tuning

    CERN Document Server

    Shirazi, Jack

    2003-01-01

    Performance has been an important issue for Java developers ever since the first version hit the streets. Over the years, Java performance has improved dramatically, but tuning is essential to get the best results, especially for J2EE applications. You can never have code that runs too fast. Java Peformance Tuning, 2nd edition provides a comprehensive and indispensable guide to eliminating all types of performance problems. Using many real-life examples to work through the tuning process in detail, JPT shows how tricks such as minimizing object creation and replacing strings with arrays can

  11. Enhancing LAN performance

    CERN Document Server

    Held, Gilbert

    2004-01-01

    Enhancing LAN Performance, Fourth Edition explains how to connect geographically separated LANs with appropriate bandwidth, the issues to consider when weighing the use of multiport or dualport devices, how to estimate traffic for new networks, the effects of configuration changes on the performance of Ethernet and Token Ring networks, the design of switch-based networks that prevent traffic bottlenecks, and other critical topics. It provides the tools to address these issues in relation to specific network requirements. This volume develops mathematical models of various LAN performance issue

  12. Breakfast and performance.

    Science.gov (United States)

    Cueto, S

    2001-12-01

    Evidence suggests that the effect of fasting on performance is not uniform, but it is dependent on the basal nutritional status of the subject. Breakfast consumption has a short-term effect in improving selected learning skills, especially work memory. School breakfast programmes have a positive effect on the nutritional status of children, on school attendance and probably on dropout rates. The effect of breakfast consumption on school performance depends on the interaction between the programme, student characteristics (malnutrition) and school organisation. Unless the school setting guarantees a minimum quality standard, the benefits of breakfast consumption will not be evident in performance in complex areas like language or maths.

  13. Nuclear performance and reliability

    International Nuclear Information System (INIS)

    Rothwell, G.

    1993-01-01

    If fewer forced outages are a sign of improved safety, nuclear power plants have become safer and more productive. There has been a significant improvement in nuclear power plant performance, due largely to a decline in the forced outage rate and a dramatic drop in the average number of forced outages per fuel cycle. If fewer forced outages are a sign of improved safety, nuclear power plants have become safer and more productive over time. To encourage further increases in performance, regulatory incentive schemes should reward reactor operators for improved reliability and safety, as well as for improved performance

  14. Clojure high performance programming

    CERN Document Server

    Kumar, Shantanu

    2013-01-01

    This is a short, practical guide that will teach you everything you need to know to start writing high performance Clojure code.This book is ideal for intermediate Clojure developers who are looking to get a good grip on how to achieve optimum performance. You should already have some experience with Clojure and it would help if you already know a little bit of Java. Knowledge of performance analysis and engineering is not required. For hands-on practice, you should have access to Clojure REPL with Leiningen.

  15. Neoliberalism, Performativity and Research

    Science.gov (United States)

    Roberts, Peter

    2007-07-01

    This paper provides a critical analysis of New Zealand's Performance Based Research Fund (PBRF). The first section sketches the development and implementation of the PBRF. The second section evaluates the scheme, concentrating on three themes: the relationship between privatization, competition and research performance; the standardization of research; and motivations for research. The paper acknowledges the thorough work completed by the Tertiary Education Advisory Commission and other policy groups in laying the foundation for the adoption of performance-based research funding in New Zealand. It is argued, however, that when viewed in its larger context, the PBRF constitutes a continuation of neoliberal trends already well established in New Zealand's tertiary education system.

  16. Performance expectation plan

    Energy Technology Data Exchange (ETDEWEB)

    Ray, P.E.

    1998-09-04

    This document outlines the significant accomplishments of fiscal year 1998 for the Tank Waste Remediation System (TWRS) Project Hanford Management Contract (PHMC) team. Opportunities for improvement to better meet some performance expectations have been identified. The PHMC has performed at an excellent level in administration of leadership, planning, and technical direction. The contractor has met and made notable improvement of attaining customer satisfaction in mission execution. This document includes the team`s recommendation that the PHMC TWRS Performance Expectation Plan evaluation rating for fiscal year 1998 be an Excellent.

  17. No Woman's Land (Performance)

    OpenAIRE

    Garton, Rosie; Rippel, IIdiko

    2017-01-01

    'No Woman's Land' (performance) is 1 hr 15 minute large-scale, multi-media performance work. In 1945, Ildikó’s grandmother Lucia Rippel, expelled from her place of birth, walked 220 miles across the fractured landscape of Europe, with her two small children and all her belongings dragged in a cart. In 2015, Ildikó and Rosie retraced her footsteps, crossing borders, climbing fences, bleeding, crying and blistering, carrying their flat-pack children. The performance is a response to ou...

  18. On Time Performance Pressure

    Science.gov (United States)

    Connell, Linda; Wichner, David; Jakey, Abegael

    2013-01-01

    Within many operations, the pressures for on-time performance are high. Each month, on-time statistics are reported to the Department of Transportation and made public. There is a natural tendency for employees under pressure to do their best to meet these objectives. As a result, pressure to get the job done within the allotted time may cause personnel to deviate from procedures and policies. Additionally, inadequate or unavailable resources may drive employees to work around standard processes that are seen as barriers. However, bypassing practices to enable on-time performance may affect more than the statistics. ASRS reports often highlight on-time performance pressures which may result in impact across all workgroups in an attempt to achieve on-time performance. Reporters often provide in-depth insights into their experiences which can be used by industry to identify and focus on the implementation of systemic fixes.

  19. Connected motorcycle system performance.

    Science.gov (United States)

    2016-01-15

    This project characterized the performance of Connected Vehicle Systems (CVS) on motorcycles based on two key components: global positioning and wireless communication systems. Considering that Global Positioning System (GPS) and 5.9 GHz Dedicated Sh...

  20. Improving fleet performance

    International Nuclear Information System (INIS)

    Ramjist, S.

    2015-01-01

    Use Fleet Initiatives to Improve Overall Fleet Performance . Tightly Integrated with Business Planning (Cause & Effect) . Leverage Strength of Broader Organization - Converge on Standard Business Practices . Ancillary Benefit of Improved Agility.