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Sample records for current task demands

  1. Task demand, task management, and teamwork

    Energy Technology Data Exchange (ETDEWEB)

    Braarud, Per Oeivind; Brendryen, Haavar

    2001-03-15

    The current approach to mental workload assessment in process control was evaluated in 3 previous HAMMLAB studies, by analysing the relationship between workload related measures and performance. The results showed that subjective task complexity rating was related to team's control room performance, that mental effort (NASA-TLX) was weakly related to performance, and that overall activity level was unrelated to performance. The results support the argument that general cognitive measures, i.e., mental workload, are weakly related to performance in the process control domain. This implies that other workload concepts than general mental workload are needed for valid assessment of human reliability and for valid assessment of control room configurations. An assessment of task load in process control suggested that how effort is used to handle task demand is more important then the level of effort invested to solve the task. The report suggests two main workload related concepts with a potential as performance predictors in process control: task requirements, and the work style describing how effort is invested to solve the task. The task requirements are seen as composed of individual task demand and team demand. In a similar way work style are seen as composed of individual task management and teamwork style. A framework for the development of the concepts is suggested based on a literature review and experiences from HAMMLAB research. It is suggested that operational definitions of workload concepts should be based on observable control room behaviour, to assure a potential for developing performance-shaping factors. Finally an explorative analysis of teamwork measures and performance in one study indicated that teamwork concepts are related to performance. This lends support to the suggested development of team demand and teamwork style as elements of a framework for the analysis of workload in process control. (Author)

  2. The impact of task demand on visual word recognition.

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    Yang, J; Zevin, J

    2014-07-11

    The left occipitotemporal cortex has been found sensitive to the hierarchy of increasingly complex features in visually presented words, from individual letters to bigrams and morphemes. However, whether this sensitivity is a stable property of the brain regions engaged by word recognition is still unclear. To address the issue, the current study investigated whether different task demands modify this sensitivity. Participants viewed real English words and stimuli with hierarchical word-likeness while performing a lexical decision task (i.e., to decide whether each presented stimulus is a real word) and a symbol detection task. General linear model and independent component analysis indicated strong activation in the fronto-parietal and temporal regions during the two tasks. Furthermore, the bilateral inferior frontal gyrus and insula showed significant interaction effects between task demand and stimulus type in the pseudoword condition. The occipitotemporal cortex showed strong main effects for task demand and stimulus type, but no sensitivity to the hierarchical word-likeness was found. These results suggest that different task demands on semantic, phonological and orthographic processes can influence the involvement of the relevant regions during visual word recognition. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  3. Task Demands in OSCEs Influence Learning Strategies.

    Science.gov (United States)

    Lafleur, Alexandre; Laflamme, Jonathan; Leppink, Jimmie; Côté, Luc

    2017-01-01

    Models on pre-assessment learning effects confirmed that task demands stand out among the factors assessors can modify in an assessment to influence learning. However, little is known about which tasks in objective structured clinical examinations (OSCEs) improve students' cognitive and metacognitive processes. Research is needed to support OSCE designs that benefit students' metacognitive strategies when they are studying, reinforcing a hypothesis-driven approach. With that intent, hypothesis-driven physical examination (HDPE) assessments ask students to elicit and interpret findings of the physical exam to reach a diagnosis ("Examine this patient with a painful shoulder to reach a diagnosis"). When studying for HDPE, students will dedicate more time to hypothesis-driven discussions and practice than when studying for a part-task OSCE ("Perform the shoulder exam"). It is expected that the whole-task nature of HDPE will lead to a hypothesis-oriented use of the learning resources, a frequent use of adjustment strategies, and persistence with learning. In a mixed-methods study, 40 medical students were randomly paired and filmed while studying together for two hypothetical OSCE stations. Each 25-min study period began with video cues asking to study for either a part-task OSCE or an HDPE. In a crossover design, sequences were randomized for OSCEs and contents (shoulder or spine). Time-on-task for discussions or practice were categorized as "hypothesis-driven" or "sequence of signs and maneuvers." Content analysis of focus group interviews summarized students' perception of learning resources, adjustment strategies, and persistence with learning. When studying for HDPE, students allocate significantly more time for hypothesis-driven discussions and practice. Students use resources contrasting diagnoses and report persistence with learning. When studying for part-task OSCEs, time-on-task is reversed, spent on rehearsing a sequence of signs and maneuvers. OSCEs with

  4. Estimating demand for alternatives to cigarettes with online purchase tasks.

    Science.gov (United States)

    O'Connor, Richard J; June, Kristie M; Bansal-Travers, Maansi; Rousu, Matthew C; Thrasher, James F; Hyland, Andrew; Cummings, K Michael

    2014-01-01

    To explore how advertising affects demand for cigarettes and potential substitutes, including snus, dissolvable tobacco, and medicinal nicotine. A Web-based experiment randomized 1062 smokers to see advertisements for alternative nicotine products or soft drinks, then complete a series of purchase tasks, which were used to estimate demand elasticity, peak consumption, and cross-price elasticity (CPE) for tobacco products. Lower demand elasticity and greater peak consumption were seen for cigarettes compared to all alternative products (p demand. These findings suggest significantly lower demand for alternative nicotine sources among smokers than previously revealed.

  5. Cognitive task demands, self-control demands and the mental well-being of office workers.

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    Bridger, Robert S; Brasher, Kate

    2011-09-01

    The cognitive task demands of office workers and the self-control demands of their work roles were measured in a sample of 196 employees in two different office layouts using a self-report questionnaire, which was circulated electronically. Multiple linear regression analysis revealed that both factors were associated with mental well-being, but not with physical well-being, while controlling for exposure to psychosocial stressors. The interaction between cognitive task demands and self-control demands had the strongest association with mental well-being, suggesting that the deleterious effect of one was greater when the other was present. An exploratory analysis revealed that the association was stronger for employees working in a large open-plan office than for those working in smaller offices with more privacy. Frustration of work goals was the cognitive task demand having the strongest negative impact on mental well-being. Methodological limitations and scale psychometrics (particularly the use of the NASA Task Load Index) are discussed. STATEMENT OF RELEVANCE: Modern office work has high mental demands and low physical demands and there is a need to design offices to prevent adverse psychological reactions. It is shown that cognitive task demands interact with self-control demands to degrade mental well-being. The association was stronger in an open-plan office.

  6. Physiological Indices of Pilots' Abilities Under Varying Task Demands.

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    Wang, Zhen; Zheng, Lingxiao; Lu, Yanyu; Fu, Shan

    2016-04-01

    This study investigated pilots' ability by examining the effects of flight experience and task demand on physiological reactions, and analyzing the diagnostic meanings underlying correlated parameters. A total of 12 experienced pilots and 12 less experienced pilots performed 4 simulated flight tasks, including normal and emergency situations. Fixation duration (FD), saccade rate (SR), blink rate (BR), heart rate (HR), respiration rate (RR), and respiration amplitude (RA) were measured during the tasks. More experienced pilots adapted their SR flexibly to changing task demands and had significantly lower SR than less experienced pilots during emergency tasks (29.6 ± 20.0 vs. 70.1 ± 67.1 saccades/min). BR, HR, and RR were affected by pilot experience but not by task demand. More experienced pilots had lower BR, HR, and RR than less experienced pilots during both normal tasks (BR: 14.3 ± 13.0 vs. 32.9 ± 25.8 blinks/min; HR: 72.7 ± 7.9 vs. 83.2 ± 7.2 bpm; RR: 15.4 ± 2.1 vs. 19.5 ± 5.2 breaths/min) and emergency tasks (BR: 10.2 ± 5.0 vs. 32.3 ± 20.8 blinks/min; HR: 73.3 ± 7.3 vs. 82.2 ± 11.6 bpm; RR: 15.6 ± 1.9 vs. 18.0 ± 3.2 breaths/min). FD and RA were not sensitive to either flight experience or task demand. Physiological reactions have the potential to reflect pilots' ability from different aspects. SR and BR could indicate pilots' differences in information access strategy. HR and RR could reflect a pilot's physical fitness. These findings are useful for understanding a pilot's ability.

  7. Hysteresis in Mental Workload and Task Performance: The Influence of Demand Transitions and Task Prioritization.

    Science.gov (United States)

    Jansen, Reinier J; Sawyer, Ben D; van Egmond, René; de Ridder, Huib; Hancock, Peter A

    2016-12-01

    We examine how transitions in task demand are manifested in mental workload and performance in a dual-task setting. Hysteresis has been defined as the ongoing influence of demand levels prior to a demand transition. Authors of previous studies predominantly examined hysteretic effects in terms of performance. However, little is known about the temporal development of hysteresis in mental workload. A simulated driving task was combined with an auditory memory task. Participants were instructed to prioritize driving or to prioritize both tasks equally. Three experimental conditions with low, high, and low task demands were constructed by manipulating the frequency of lane changing. Multiple measures of subjective mental workload were taken during experimental conditions. Contrary to our prediction, no hysteretic effects were found after the high- to low-demand transition. However, a hysteretic effect in mental workload was found within the high-demand condition, which degraded toward the end of the high condition. Priority instructions were not reflected in performance. Online assessment of both performance and mental workload demonstrates the transient nature of hysteretic effects. An explanation for the observed hysteretic effect in mental workload is offered in terms of effort regulation. An informed arrival at the scene is important in safety operations, but peaks in mental workload should be avoided to prevent buildup of fatigue. Therefore, communication technologies should incorporate the historical profile of task demand. © 2016, Human Factors and Ergonomics Society.

  8. Task demands and individual variation in referring expressions

    NARCIS (Netherlands)

    Baltaretu, Adriana-Alexandra; Castro Ferreira, Thiago

    Aiming to improve the human-likeness of natural language generation systems, this study investigates different sources of variation that might influence the production of referring expressions (REs), namely the effect of task demands and inter- intra- individual variation. We collected REs using a

  9. Children's Choice Strategies: The Effects of Age and Task Demands

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    Bereby-Meyer, Yoella; Assor, Avi; Katz, Idit

    2004-01-01

    Two experiments examined the effect of age and cognitive demands on children's choice strategies. Children aged 8-9 and 12-13 years were asked to choose among either two or four products that differed in several attributes of varying importance to them. Choice tasks were designed to differentiate between the lexicographic and the equal-weighting…

  10. Selection of spatial reference frames depends on task's demands

    Directory of Open Access Journals (Sweden)

    Greeshma Sharma

    2016-12-01

    Full Text Available Spatial reference frames (SRF are the means of representing spatial relations or locations either in an egocentric coordinate system (centred on navigator or in an allocentric coordinate system (Centred on object. It is necessary to understand when and how spatial representation switches between allocentric and egocentric reference frames in context to spatial tasks. The objective of this study was to explore if the elementary spatial representation does exist, whether it would remain consistent or change under the influence of a task's demand. Also, we explored how the SRF would assist if the environment is enriched with landmarks, having multiple routes for wayfinding. The results showed that the switching of SRF depends not only on the default representation but also on a task's demand. They also demonstrated that participants who were using allocentric representation performed better in the presence of landmarks.

  11. Enhancing perceptual and attentional skills requires common demands between the action video games and transfer tasks

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    Oei, Adam C.; Patterson, Michael D.

    2015-01-01

    Despite increasing evidence that shows action video game play improves perceptual and cognitive skills, the mechanisms of transfer are not well-understood. In line with previous work, we suggest that transfer is dependent upon common demands between the game and transfer task. In the current study, participants played one of four action games with varying speed, visual, and attentional demands for 20 h. We examined whether training enhanced performance for attentional blink, selective attention, attending to multiple items, visual search and auditory detection. Non-gamers who played the game (Modern Combat) with the highest demands showed transfer to tasks of attentional blink and attending to multiple items. The game (MGS Touch) with fewer attentional demands also decreased attentional blink, but to a lesser degree. Other games failed to show transfer, despite having many action game characteristics but at a reduced intensity. The results support the common demands hypothesis. PMID:25713551

  12. Enhancing perceptual and attentional skills requires common demands between the action video games and transfer tasks.

    Science.gov (United States)

    Oei, Adam C; Patterson, Michael D

    2015-01-01

    Despite increasing evidence that shows action video game play improves perceptual and cognitive skills, the mechanisms of transfer are not well-understood. In line with previous work, we suggest that transfer is dependent upon common demands between the game and transfer task. In the current study, participants played one of four action games with varying speed, visual, and attentional demands for 20 h. We examined whether training enhanced performance for attentional blink, selective attention, attending to multiple items, visual search and auditory detection. Non-gamers who played the game (Modern Combat) with the highest demands showed transfer to tasks of attentional blink and attending to multiple items. The game (MGS Touch) with fewer attentional demands also decreased attentional blink, but to a lesser degree. Other games failed to show transfer, despite having many action game characteristics but at a reduced intensity. The results support the common demands hypothesis.

  13. Enhancing perceptual and attentional skills requires common demands between the action video games and transfer tasks

    Directory of Open Access Journals (Sweden)

    Adam C Oei

    2015-02-01

    Full Text Available Despite increasing evidence that shows action video game play improves perceptual and cognitive skills, the mechanisms of transfer are not well understood. In line with previous work, we suggest that transfer is dependent upon common demands between the game and transfer task. In the current study, participants played one of four action games with varying speed, visual, and attentional demands for twenty hours. We examined whether training enhanced performance for attentional blink, selective attention, attending to multiple items, visual search and auditory detection. Non-gamers who played the game (Modern Combat with the highest demands showed transfer to tasks of attentional blink and attending to multiple items. The game (MGS Touch with fewer attentional demands also decreased attentional blink, but to a lesser degree. Other games failed to show transfer, despite having many action game characteristics but at a reduced intensity. The results support the common demands hypothesis

  14. Frequency modulation of neural oscillations according to visual task demands.

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    Wutz, Andreas; Melcher, David; Samaha, Jason

    2018-02-06

    Temporal integration in visual perception is thought to occur within cycles of occipital alpha-band (8-12 Hz) oscillations. Successive stimuli may be integrated when they fall within the same alpha cycle and segregated for different alpha cycles. Consequently, the speed of alpha oscillations correlates with the temporal resolution of perception, such that lower alpha frequencies provide longer time windows for perceptual integration and higher alpha frequencies correspond to faster sampling and segregation. Can the brain's rhythmic activity be dynamically controlled to adjust its processing speed according to different visual task demands? We recorded magnetoencephalography (MEG) while participants switched between task instructions for temporal integration and segregation, holding stimuli and task difficulty constant. We found that the peak frequency of alpha oscillations decreased when visual task demands required temporal integration compared with segregation. Alpha frequency was strategically modulated immediately before and during stimulus processing, suggesting a preparatory top-down source of modulation. Its neural generators were located in occipital and inferotemporal cortex. The frequency modulation was specific to alpha oscillations and did not occur in the delta (1-3 Hz), theta (3-7 Hz), beta (15-30 Hz), or gamma (30-50 Hz) frequency range. These results show that alpha frequency is under top-down control to increase or decrease the temporal resolution of visual perception.

  15. The effect of task demand and incentive on neurophysiological and cardiovascular markers of effort.

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    Fairclough, Stephen H; Ewing, Kate

    2017-09-01

    According to motivational intensity theory, effort is proportional to the level of task demand provided that success is possible and successful performance is deemed worthwhile. The current study represents a simultaneous manipulation of demand (working memory load) and success importance (financial incentive) to investigate neurophysiological (EEG) and cardiovascular measures of effort. A 2×2 repeated-measures study was conducted where 18 participants performed a n-back task under three conditions of demand: easy (1-back), hard (4-back) and very hard (7-back). In addition, participants performed these tasks in the presence of performance-contingent financial incentive or in a no-incentive (pilot trial) condition. Three bands of EEG activity were quantified: theta (4-7Hz), lower-alpha (7.5-10Hz) and upper-alpha (10.5-13Hz). Fronto-medial activity in the theta band and activity in the upper-alpha band at frontal, central and parietal sites were sensitive to demand and indicated greatest effort when the task was challenging and success was possible. Mean systolic blood pressure and activity in the lower-alpha band at parietal sites were also sensitive to demand but also increased in the incentive condition across all levels of task demand. The results of the study largely support the predictions of motivational intensity using neurophysiological markers of effort. Copyright © 2017. Published by Elsevier B.V.

  16. Blocking-out auditory distracters while driving : A cognitive strategy to reduce task-demands on the road

    NARCIS (Netherlands)

    Unal, Ayca Berfu; Platteel, Samantha; Steg, Linda; Epstude, Kai

    The current research examined how drivers handle task-demands induced by listening to the radio while driving. In particular, we explored the traces of a possible cognitive strategy that might be used by drivers to cope with task-demands, namely blocking-out auditory distracters. In Study 1 (N =

  17. Effect of task demands on dual coding of pictorial stimuli.

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    Babbitt, B C

    1982-01-01

    Recent studies have suggested that verbal labeling of a picture does not occur automatically. Although several experiments using paired-associate tasks produced little evidence indicating the use of a verbal code with picture stimuli, the tasks were probably not sensitive to whether the codes were activated initially. It is possible that verbal labels were activated at input, but not used later in performing the tasks. The present experiment used a color-naming interference task in order to assess, with a more sensitive measure, the amount of verbal coding occurring in response to word or picture input. Subjects named the color of ink in which words were printed following either word or picture input. If verbal labeling of the input occurs, then latency of color naming should increase when the input item and color-naming word are related. The results provided substantial evidence of such verbal activation when the input items were words. However, the presence of verbal activation with picture input was a function of task demands. Activation occurred when a recall memory test was used, but not when a recognition memory test was used. The results support the conclusion that name information (labels) need not be activated during presentation of visual stimuli.

  18. Production practices affecting worker task demands in concrete operations: A case study.

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    Memarian, Babak; Mitropoulos, Panagiotis

    2015-01-01

    Construction work involves significant physical, mental, and temporal task demands. Excessive task demands can have negative consequences for safety, errors and production. This exploratory study investigates the magnitude and sources of task demands on a concrete operation, and examines the effect of the production practices on the workers' task demands. The NASA Task Load Index was used to measure the perceived task demands of two work crews. The operation involved the construction of a cast-in-place concrete building under high schedule pressures. Interviews with each crew member were used to identify the main sources of the perceived demands. Extensive field observations and interviews with the supervisors and crews identified the production practices. The workers perceived different level of task demands depending on their role. The production practices influenced the task demands in two ways: (1) practices related to work organization, task design, resource management, and crew management mitigated the task demands; and (2) other practices related to work planning and crew management increased the crew's ability to cope with and adapt to high task demands. The findings identify production practices that regulate the workers' task demands. The effect of task demands on performance is mitigated by the ability to cope with high demands.

  19. Task demands moderate stereotype threat effects on memory performance.

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    Hess, Thomas M; Emery, Lisa; Queen, Tara L

    2009-06-01

    Previous research has demonstrated that older adults' memory performance is adversely affected by the explicit activation of negative stereotypes about aging. In this study, we examined the impact of stereotype threat on recognition memory, with specific interest in (a) the generalizability of previously observed effects, (b) the subjective experience of memory, and (c) the moderating effects of task demands. Older participants subjected to threat performed worse than did those in a nonthreat condition but only when performance constraints were high (i.e., memory decisions had to be made within a limited time frame). This effect was reflected in the subjective experience of memory, with participants in this condition having a lower ratio of "remember" to "know" responses. The absence of threat effects when constraints were minimal provides important boundary information regarding stereotype influences on memory performance.

  20. Estimating Demand and Cross-Price Elasticity for Very Low Nicotine Content (VLNC) Cigarettes Using a Simulated Demand Task.

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    Tucker, Megan R; Laugesen, Murray; Grace, Randolph C

    2017-03-03

    Very Low Nicotine Content (VLNC) cigarettes might be useful as part of a tobacco control strategy, but relatively little is known about their acceptability as substitutes for regular cigarettes. We compared subjective effects and demand for regular cigarettes and Very Low Nicotine Content (VLNC) cigarettes, and estimated cross-price elasticity for VLNC cigarettes, using simulated demand tasks. 40 New Zealand smokers sampled a VLNC cigarette and completed Cigarette Purchase Tasks to indicate their demand for regular cigarettes and VLNC cigarettes at a range of prices, and a cross-price task indicating how many regular cigarettes and VLNC cigarettes they would purchase at 0.5x, 1x, and 2x the current market price for regular cigarettes, assuming the price of VLNC cigarettes remained constant. They also rated the subjective effects of the VLNC cigarette and their usual-brand regular cigarettes. Cross-price elasticity for VLNC cigarettes was estimated as 0.24 and was significantly positive, indicating that VLNC cigarettes are partially substitutable for regular cigarettes. VLNC cigarettes were rated as less satisfying and psychologically rewarding than regular cigarettes, but this was unrelated to demand or substitutability. VLNC cigarettes are potentially substitutable for regular cigarettes. Their availability may reduce tobacco consumption, nicotine intake and addiction; making it easier for smokers to quit. VLNC cigarettes share the behavioural and sensory components of smoking whilst delivering negligible levels of nicotine. Although smokers rated VLNCs as less satisfying than regular cigarettes, smokers said they would increase their consumption of VLNCs as the price of regular cigarettes increased, if VLNCs were available at a lower price. This suggests that VLNCs are partially substitutable for regular cigarettes. VLNCs can be part of an effective tobacco control strategy, by reducing nicotine dependence and improving health and financial outcomes for smokers

  1. Too easy? The influence of task demands conveyed tacitly on prospective memory

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    Lourenço, Joana S.; Hill, Johnathan H.; Maylor, Elizabeth A.

    2015-01-01

    Previous research suggests that when intentions are encoded, participants establish an attention allocation policy based on their metacognitive beliefs about how demanding it will be to fulfill the prospective memory (PM) task. We investigated whether tacit PM demands can influence judgments about the cognitive effort required for success, and, as a result, affect ongoing task interference and PM performance. Participants performed a lexical decision task in which a PM task of responding to animal words was embedded. PM demands were tacitly manipulated by presenting participants with either typical or atypical animal exemplars at both instructions and practice (low vs. high tacit demands, respectively). Crucially, objective PM task demands were the same for all participants as PM targets were always atypical animals. Tacit demands affected participants’ attention allocation policies such that task interference was greater for the high than low demands condition. Also, PM performance was reduced in the low relative to the high demands condition. Participants in the low demands condition who succeeded to the first target showed a subsequent increase in task interference, suggesting adjustment to the higher than expected demands. This study demonstrates that tacit information regarding the PM task can affect ongoing task processing as well as harm PM performance when actual demands are higher than expected. Furthermore, in line with the proposal that attention allocation is a dynamic and flexible process, we found evidence that PM task experience can trigger changes in ongoing task interference. PMID:25983687

  2. Task demands determine comparison strategy in whole probe change detection.

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    Udale, Rob; Farrell, Simon; Kent, Chris

    2018-05-01

    Detecting a change in our visual world requires a process that compares the external environment (test display) with the contents of memory (study display). We addressed the question of whether people strategically adapt the comparison process in response to different decision loads. Study displays of 3 colored items were presented, followed by 'whole-display' probes containing 3 colored shapes. Participants were asked to decide whether any probed items contained a new feature. In Experiments 1-4, irrelevant changes to the probed item's locations or feature bindings influenced memory performance, suggesting that participants employed a comparison process that relied on spatial locations. This finding occurred irrespective of whether participants were asked to decide about the whole display, or only a single cued item within the display. In Experiment 5, when the base-rate of changes in the nonprobed items increased (increasing the incentive to use the cue effectively), participants were not influenced by irrelevant changes in location or feature bindings. In addition, we observed individual differences in the use of spatial cues. These results suggest that participants can flexibly switch between spatial and nonspatial comparison strategies, depending on interactions between individual differences and task demand factors. These findings have implications for models of visual working memory that assume that the comparison between study and test obligatorily relies on accessing visual features via their binding to location. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  3. Measuring cognitive task demands using dual task methodology, subjective self-ratings, and expert judgments : A Validation Study

    NARCIS (Netherlands)

    Révész, Andrea; Michel, Marije; Gilabert, Roger

    2016-01-01

    This study explored the usefulness of dual-task methodology, self-ratings, and expert judgements in assessing task-generated cognitive demands as a way to provide validity evidence for manipulations of task complexity. The participants were 96 students and 61 ESL teachers. The students, 48 English

  4. Measuring Cognitive Task Demands Using Dual-Task Methodology, Subjective Self-Ratings, and Expert Judgments: A Validation Study

    Science.gov (United States)

    Revesz, Andrea; Michel, Marije; Gilabert, Roger

    2016-01-01

    This study explored the usefulness of dual-task methodology, self-ratings, and expert judgments in assessing task-generated cognitive demands as a way to provide validity evidence for manipulations of task complexity. The participants were 96 students and 61 English as a second language (ESL) teachers. The students, 48 English native speakers and…

  5. Developmental changes in using verbal self-cueing in task-switching situations: the impact of task practice and task-sequencing demands

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    Kray, Jutta; Gaspard, Hanna; Karbach, Julia; Blaye, Agnès

    2013-01-01

    In this study we examined whether developmental changes in using verbal self-cueing for task-goal maintenance are dependent on the amount of task practice and task-sequencing demands. To measure task-goal maintenance we applied a switching paradigm in which children either performed only task A or B in single-task blocks or switched between them on every second trial in mixed-task blocks. Task-goal maintenance was determined by comparing the performance between both blocks (mixing costs). The influence of verbal self-cueing was measured by instructing children to either name the next task aloud or not to verbalize during task preparation. Task-sequencing demands were varied between groups whereas one group received spatial task cues to support keeping track of the task sequence, while the other group did not. We also varied by the amount of prior practice in task switching while one group of participants practiced task switching first, before performing the task naming in addition, and the other group did it vice versa. Results of our study investigating younger (8–10 years) and older children (11–13 years) revealed no age differences in beneficial effects of verbal self-cueing. In line with previous findings, children showed reduced mixing costs under task-naming instructions and under conditions of low task-sequence demands (with the presence of spatial task cues). Our results also indicated that these benefits were only obtained for those groups of children that first received practice in task switching alone with no additional verbalization instruction. These findings suggest that internal task-cueing strategies can be efficiently used in children but only if they received prior practice in the underlying task so that demands on keeping and coordinating various instructions are reduced. Moreover, children benefitted from spatial task cues for better task-goal maintenance only if no verbal task-cueing strategy was introduced first. PMID:24381566

  6. The role of metacognition in prospective memory: anticipated task demands influence attention allocation strategies.

    Science.gov (United States)

    Rummel, Jan; Meiser, Thorsten

    2013-09-01

    The present study investigates how individuals distribute their attentional resources between a prospective memory task and an ongoing task. Therefore, metacognitive expectations about the attentional demands of the prospective-memory task were manipulated while the factual demands were held constant. In Experiments 1a and 1b, we found attentional costs from a prospective-memory task with low factual demands to be significantly reduced when information about the low to-be-expected demands were provided, while prospective-memory performance remained largely unaffected. In Experiment 2, attentional monitoring in a more demanding prospective-memory task also varied with information about the to-be-expected demands (high vs. low) and again there were no equivalent changes in prospective-memory performance. These findings suggest that attention-allocation strategies of prospective memory rely on metacognitive expectations about prospective-memory task demands. Furthermore, the results suggest that attentional monitoring is only functional for prospective memory to the extent to which anticipated task demands reflect objective task demands. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Cardiac responsiveness to attention-demanding tasks in socially maladaptive children

    NARCIS (Netherlands)

    Althaus, M; Aarnoudse, CC; Minderaa, RB; Mulder, Gysbertus; Mulder, Lambertus

    Cardiac responsiveness to attention-demanding tasks in socially maladaptive children A psychofysiological study of the cardiac adaptivity to attention-demanding reaction time tasks demonstrated that children with a lesser variant of the pervasive developmental disorder (DSM-IV: PDDNOS) exhibit less

  8. Skills-demands compatibility as a determinant of flow experience in an inductive reasoning task.

    Science.gov (United States)

    Schiefele, Ulrich; Raabe, Andreas

    2011-10-01

    The skills-demands fit hypothesis of flow theory was examined. Based on the earlier finding that high demands in a game situation do not reduce the experience of flow, a cognitive task paradigm was used. The effect of skills-demands compatibility on the experience of flow but not of other, similar psychological states (i.e., concentration, negative and positive activation) was also investigated. Participants were 89 undergraduate students who worked on a number of inductive reasoning tasks in four successive trials with or without skills-demands compatibility. The results clearly supported the skills-demands fit hypothesis; concentration and activation were affected only by the tasks' difficulty. Inductive reasoning tasks are a useful tool for the experimental analysis of flow, and skills-demands compatibility is a significant and powerful condition of flow, but not of other, similar psychological states.

  9. How task demands shape brain responses to visual food cues.

    Science.gov (United States)

    Pohl, Tanja Maria; Tempelmann, Claus; Noesselt, Toemme

    2017-06-01

    Several previous imaging studies have aimed at identifying the neural basis of visual food cue processing in humans. However, there is little consistency of the functional magnetic resonance imaging (fMRI) results across studies. Here, we tested the hypothesis that this variability across studies might - at least in part - be caused by the different tasks employed. In particular, we assessed directly the influence of task set on brain responses to food stimuli with fMRI using two tasks (colour vs. edibility judgement, between-subjects design). When participants judged colour, the left insula, the left inferior parietal lobule, occipital areas, the left orbitofrontal cortex and other frontal areas expressed enhanced fMRI responses to food relative to non-food pictures. However, when judging edibility, enhanced fMRI responses to food pictures were observed in the superior and middle frontal gyrus and in medial frontal areas including the pregenual anterior cingulate cortex and ventromedial prefrontal cortex. This pattern of results indicates that task sets can significantly alter the neural underpinnings of food cue processing. We propose that judging low-level visual stimulus characteristics - such as colour - triggers stimulus-related representations in the visual and even in gustatory cortex (insula), whereas discriminating abstract stimulus categories activates higher order representations in both the anterior cingulate and prefrontal cortex. Hum Brain Mapp 38:2897-2912, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  10. The Impact of Task Demands on Fixation-Related Brain Potentials during Guided Search.

    Directory of Open Access Journals (Sweden)

    Anthony J Ries

    Full Text Available Recording synchronous data from EEG and eye-tracking provides a unique methodological approach for measuring the sensory and cognitive processes of overt visual search. Using this approach we obtained fixation related potentials (FRPs during a guided visual search task specifically focusing on the lambda and P3 components. An outstanding question is whether the lambda and P3 FRP components are influenced by concurrent task demands. We addressed this question by obtaining simultaneous eye-movement and electroencephalographic (EEG measures during a guided visual search task while parametrically modulating working memory load using an auditory N-back task. Participants performed the guided search task alone, while ignoring binaurally presented digits, or while using the auditory information in a 0, 1, or 2-back task. The results showed increased reaction time and decreased accuracy in both the visual search and N-back tasks as a function of auditory load. Moreover, high auditory task demands increased the P3 but not the lambda latency while the amplitude of both lambda and P3 was reduced during high auditory task demands. The results show that both early and late stages of visual processing indexed by FRPs are significantly affected by concurrent task demands imposed by auditory working memory.

  11. U.S. Army Physical Demands Study: Reliability of Simulations of Physically Demanding Tasks Performed by Combat Arms Soldiers.

    Science.gov (United States)

    Foulis, Stephen A; Redmond, Jan E; Frykman, Peter N; Warr, Bradley J; Zambraski, Edward J; Sharp, Marilyn A

    2017-12-01

    Foulis, SA, Redmond, JE, Frykman, PN, Warr, BJ, Zambraski, EJ, and Sharp, MA. U.S. Army physical demands study: reliability of simulations of physically demanding tasks performed by combat arms soldiers. J Strength Cond Res 31(12): 3245-3252, 2017-Recently, the U.S. Army has mandated that soldiers must successfully complete the physically demanding tasks of their job to graduate from their Initial Military Training. Evaluating individual soldiers in the field is difficult; however, simulations of these tasks may aid in the assessment of soldiers' abilities. The purpose of this study was to determine the reliability of simulated physical soldiering tasks relevant to combat arms soldiers. Three cohorts of ∼50 soldiers repeated a subset of 8 simulated tasks 4 times over 2 weeks. Simulations included: sandbag carry, casualty drag, and casualty evacuation from a vehicle turret, move under direct fire, stow ammunition on a tank, load the main gun of a tank, transferring ammunition with a field artillery supply vehicle, and a 4-mile foot march. Reliability was assessed using intraclass correlation coefficients (ICCs), standard errors of measurement (SEMs), and 95% limits of agreement. Performance of the casualty drag and foot march did not improve across trials (p > 0.05), whereas improvements, suggestive of learning effects, were observed on the remaining 6 tasks (p ≤ 0.05). The ICCs ranged from 0.76 to 0.96, and the SEMs ranged from 3 to 16% of the mean. These 8 simulated tasks show high reliability. Given proper practice, they are suitable for evaluating the ability of Combat Arms Soldiers to complete the physical requirements of their jobs.

  12. Cognitive and collaborative demands of freight conductor activities: results and implications of a cognitive task analysis

    Science.gov (United States)

    2012-07-31

    This report presents the results of a cognitive task analysis (CTA) that examined the cognitive and collaborative demands placed on conductors, as well as the knowledge and skills that experienced conductors have developed that enable them to operate...

  13. An update of the Canadian initiatives of IEA Task 13 : demand response resources

    International Nuclear Information System (INIS)

    Malme, R. |; International Energy Agency, Paris

    2006-01-01

    The International Energy Agency Demand Side Management (IEA DSM) program is an international collaboration with 17 IEA member countries and the European Commission. The program aims to clarify and promote opportunities for DSM through load management, energy efficiency and strategic conservation. Task 13 of the program is charged with reviewing demand response resource (DRR) practices in various markets around the world and developing recommendations and tools for integrating DRR into regular market activities. The Ontario Power Authority (OPA), National Research Council (NRC) and CEA Technologies Inc. (CEATI) are leading participation in Task 13 in Canada. The team is currently collecting market information as well as creating tools to provide references to activities in other markets. This presentation reviewed the team's subtasks, which include: the development of DR market benchmarks and translation methods; the collection of DR consumer surveys and utilization methods; the creation of a DR market potential calculator to provide estimates for generating target marketing strategies; the creation of a valuation guide for technical users, administrators and regulators; a catalogue describing the technologies and systems that are available for use in DR programs; identifying market barriers; and the creation of a web portal that will be a virtual centre of excellence concerning DR methods, technologies and applications. DR programs in Norway, Finland, the Netherlands were also reviewed. refs., tabs., figs

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

    Science.gov (United States)

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

    2016-01-01

    This study investigated variations in heart rate variability (HRV) as a function of cognitive demands. Participants completed an execution condition including the psychomotor vigilance task, a working memory task and a duration discrimination task. The control condition consisted of oddball versions (participants had to detect the rare event) of the tasks from the execution condition, designed to control for the effect of the task parameters (stimulus duration and stimulus rate) on HRV. The NASA-TLX questionnaire was used as a subjective measure of cognitive workload across tasks and conditions. Three major findings emerged from this study. First, HRV varied as a function of task demands (with the lowest values in the working memory task). Second, and crucially, we found similar HRV values when comparing each of the tasks with its oddball control equivalent, and a significant decrement in HRV as a function of time-on-task. Finally, the NASA-TLX results showed larger cognitive workload in the execution condition than in the oddball control condition, and scores variations as a function of task. Taken together, our results suggest that HRV is highly sensitive to overall demands of sustained attention over and above the influence of other cognitive processes suggested by previous literature. In addition, our study highlights a potential dissociation between objective and subjective measures of mental workload, with important implications in applied settings. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Effect of aging on performance, muscle activation and perceived stress during mentally demanding computer tasks

    DEFF Research Database (Denmark)

    Alkjaer, Tine; Pilegaard, Marianne; Bakke, Merete

    2005-01-01

    OBJECTIVES: This study examined the effects of age on performance, muscle activation, and perceived stress during computer tasks with different levels of mental demand. METHODS: Fifteen young and thirteen elderly women performed two computer tasks [color word test and reference task] with different...... levels of mental demand but similar physical demands. The performance (clicking frequency, percentage of correct answers, and response time for correct answers) and electromyography from the forearm, shoulder, and neck muscles were recorded. Visual analogue scales were used to measure the participants......' perception of the stress and difficulty related to the tasks. RESULTS: Performance decreased significantly in both groups during the color word test in comparison with performance on the reference task. However, the performance reduction was more pronounced in the elderly group than in the young group...

  16. Balancing the Demands of Two Tasks: An Investigation of Cognitive-Motor Dual-Tasking in Relapsing Remitting Multiple Sclerosis.

    Science.gov (United States)

    Butchard-MacDonald, Emma; Paul, Lorna; Evans, Jonathan J

    2018-03-01

    People with relapsing remitting multiple sclerosis (PwRRMS) suffer disproportionate decrements in gait under dual-task conditions, when walking and a cognitive task are combined. There has been much less investigation of the impact of cognitive demands on balance. This study investigated whether: (1) PwRRMS show disproportionate decrements in postural stability under dual-task conditions compared to healthy controls, and (2) dual-task decrements are associated with everyday dual-tasking difficulties. The impact of mood, fatigue, and disease severity on dual-tasking was also examined. A total of 34 PwRRMS and 34 matched controls completed cognitive (digit span) and balance (movement of center of pressure on Biosway on stable and unstable surfaces) tasks under single- and dual-task conditions. Everyday dual-tasking was measured using the Dual-Tasking Questionnaire. Mood was measured by the Hospital Anxiety & Depression Scale. Fatigue was measured via the Modified Fatigue Index Scale. No differences in age, gender, years of education, estimated pre-morbid IQ, or baseline digit span between groups. Compared with controls, PwRRMS showed significantly greater decrement in postural stability under dual-task conditions on an unstable surface (p=.007), but not a stable surface (p=.679). Balance decrement scores were not correlated with everyday dual-tasking difficulties or fatigue. Stable surface balance decrement scores were significantly associated with levels of anxiety (rho=0.527; p=.001) and depression (rho=0.451; p=.007). RRMS causes dual-tasking difficulties, impacting balance under challenging conditions, which may contribute to increased risk of gait difficulties and falls. The relationship between anxiety/depression and dual-task decrement suggests that emotional factors may be contributing to dual-task difficulties. (JINS, 2018, 24, 247-258).

  17. Effects of Cognitive Demand on Situational Interest and Running Task Performances

    Science.gov (United States)

    Zhu, Xihe; Chen, Senlin

    2017-01-01

    This study examined the effect of cognitive demand on situational interest and performance using running tasks in physical education. Adolescents (N = 179) participated in a field study involving three different levels of cognitive demand. Running performances and situational interest were measured four times with a testing interval of seven days.…

  18. Planning and Enacting Mathematical Tasks of High Cognitive Demand in the Primary Classroom

    Science.gov (United States)

    Georgius, Kelly

    2013-01-01

    This study offers an examination of two primary-grades teachers as they learn to transfer knowledge from professional development into their classrooms. I engaged in planning sessions with each teacher to help plan tasks of high cognitive demand, including anticipating and planning for classroom discourse that would occur around the task. A…

  19. Trial-to-trial reoptimization of motor behavior due to changes in task demands is limited.

    Directory of Open Access Journals (Sweden)

    Orban de Xivry J-J

    Full Text Available Each task requires a specific motor behavior that is tuned to task demands. For instance, writing requires a lot of accuracy while clapping does not. It is known that the brain adjusts the motor behavior to different task demands as predicted by optimal control theory. In this study, the mechanism of this reoptimization process is investigated by varying the accuracy demands of a reaching task. In this task, the width of the reaching target (0.5 or 8 cm was varied either on a trial-to-trial basis (random schedule or in blocks (blocked schedule. On some trials, the hand of the subjects was clamped to a rectilinear trajectory that ended 2 cm on the left or right of the target center. The rejection of this perturbation largely varied with target width in the blocked schedule but not in the random schedule. That is, subjects exhibited different motor behavior in the different schedules despite identical accuracy demands. Therefore, while reoptimization has been considered immediate and automatic, the differences in motor behavior observed across schedules suggest that the reoptimization of the motor behavior is neither happening on a trial-by-trial basis nor obligatory. The absence of trial-to-trial mechanisms, the inability of the brain to adapt to two conflicting task demands and the existence of a switching cost are discussed as possible sources of the non-optimality of motor behavior during the random schedule.

  20. Attentional Demand of a Virtual Reality-Based Reaching Task in Nondisabled Older Adults

    Science.gov (United States)

    Chen, Yi-An; Chung, Yu-Chen; Proffitt, Rachel; Wade, Eric; Winstein, Carolee

    2015-01-01

    Attention during exercise is known to affect performance; however, the attentional demand inherent to virtual reality (VR)-based exercise is not well understood. We used a dual-task paradigm to compare the attentional demands of VR-based and non-VR-based (conventional, real-world) exercise: 22 non-disabled older adults performed a primary reaching task to virtual and real targets in a counterbalanced block order while verbally responding to an unanticipated auditory tone in one third of the trials. The attentional demand of the primary reaching task was inferred from the voice response time (VRT) to the auditory tone. Participants' engagement level and task experience were also obtained using questionnaires. The virtual target condition was more attention demanding (significantly longer VRT) than the real target condition. Secondary analyses revealed a significant interaction between engagement level and target condition on attentional demand. For participants who were highly engaged, attentional demand was high and independent of target condition. However, for those who were less engaged, attentional demand was low and depended on target condition (i.e., virtual > real). These findings add important knowledge to the growing body of research pertaining to the development and application of technology-enhanced exercise for elders and for rehabilitation purposes. PMID:27004233

  1. Attentional Demand of a Virtual Reality-Based Reaching Task in Nondisabled Older Adults.

    Science.gov (United States)

    Chen, Yi-An; Chung, Yu-Chen; Proffitt, Rachel; Wade, Eric; Winstein, Carolee

    2015-12-01

    Attention during exercise is known to affect performance; however, the attentional demand inherent to virtual reality (VR)-based exercise is not well understood. We used a dual-task paradigm to compare the attentional demands of VR-based and non-VR-based (conventional, real-world) exercise: 22 non-disabled older adults performed a primary reaching task to virtual and real targets in a counterbalanced block order while verbally responding to an unanticipated auditory tone in one third of the trials. The attentional demand of the primary reaching task was inferred from the voice response time (VRT) to the auditory tone. Participants' engagement level and task experience were also obtained using questionnaires. The virtual target condition was more attention demanding (significantly longer VRT) than the real target condition. Secondary analyses revealed a significant interaction between engagement level and target condition on attentional demand. For participants who were highly engaged, attentional demand was high and independent of target condition. However, for those who were less engaged, attentional demand was low and depended on target condition (i.e., virtual > real). These findings add important knowledge to the growing body of research pertaining to the development and application of technology-enhanced exercise for elders and for rehabilitation purposes.

  2. Cognitive Demands Influence Lower Extremity Mechanics During a Drop Vertical Jump Task in Female Athletes.

    Science.gov (United States)

    Almonroeder, Thomas Gus; Kernozek, Thomas; Cobb, Stephen; Slavens, Brooke; Wang, Jinsung; Huddleston, Wendy

    2018-05-01

    Study Design Cross-sectional study. Background The drop vertical jump task is commonly used to screen for anterior cruciate ligament injury risk; however, its predictive validity is limited. The limited predictive validity of the drop vertical jump task may be due to not imposing the cognitive demands that reflect sports participation. Objectives To investigate the influence of additional cognitive demands on lower extremity mechanics during execution of the drop vertical jump task. Methods Twenty uninjured women (age range, 18-25 years) were required to perform the standard drop vertical jump task, as well as drop vertical jumps that included additional cognitive demands. The additional cognitive demands were related to attending to an overhead goal (ball suspended overhead) and/or temporal constraints on movement selection (decision making). Three-dimensional ground reaction forces and lower extremity mechanics were compared between conditions. Results The inclusion of the overhead goal resulted in higher peak vertical ground reaction forces and lower peak knee flexion angles in comparison to the standard drop vertical jump task. In addition, participants demonstrated greater peak knee abduction angles when trials incorporated temporal constraints on decision making and/or required participants to attend to an overhead goal, in comparison to the standard drop vertical jump task. Conclusion Imposing additional cognitive demands during execution of the drop vertical jump task influenced lower extremity mechanics in a manner that suggested increased loading of the anterior cruciate ligament. Tasks utilized in anterior cruciate ligament injury risk screening may benefit from more closely reflecting the cognitive demands of the sports environment. J Orthop Sports Phys Ther 2018;48(5):381-387. Epub 10 Jan 2018. doi:10.2519/jospt.2018.7739.

  3. Improved proprioceptive function by application of subsensory electrical noise: Effects of aging and task-demand.

    Science.gov (United States)

    Toledo, Diana R; Barela, José A; Kohn, André F

    2017-09-01

    The application of subsensory noise stimulation over the lower limbs has been shown to improve proprioception and postural control under certain conditions. Whereas the effect specificity seems to depend on several factors, studies are still needed to determine the appropriate method for training and rehabilitation purposes. In the current study, we investigated whether the application of subsensory electrical noise over the legs improves proprioceptive function in young and older adults. We aimed to provide evidence that stronger and age-related differential effects occur in more demanding tasks. Proprioceptive function was initially assessed by testing the detection of passive ankle movement (kinesthetic perception) in twenty-eight subjects (14 young and 14 older adults). Thereafter, postural control was assessed during tasks with different sensory challenges: i) by removing visual information (eyes closed) and; ii) by moving the visual scene (moving room paradigm). Tests performed with the application of electrical noise stimulation were compared to those performed without noise. The results showed that electrical noise applied over the legs led to a reduction in the response time to kinesthetic perception in both young and older adults. On the other hand, the magnitude of postural sway was reduced by noise stimulation only during a more challenging task, namely, when the optical flow was changing in an unpredictable (nonperiodic) manner. No differential effects of stimulation between groups were observed. These findings suggest that the relevance of proprioceptive inputs in tasks with different challenges, but not the subjects' age, is a determining factor for sensorimotor improvements due to electrical noise stimulation. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  4. Task parameters affecting ergonomic demands and productivity of HVAC duct installation.

    Science.gov (United States)

    Mitropoulos, Panagiotis; Hussain, Sanaa; Guarascio-Howard, Linda; Memarian, Babak

    2014-01-01

    Mechanical installation workers experience work-related musculoskeletal disorders (WMSDs) at high rates. (1) Quantify the ergonomic demands during HVAC installation, (2) identify the tasks and task parameters that generated extreme ergonomic demands, and (3) propose improvements to reduce the WMSDs among mechanical workers. The study focused on installation of rectangular ductwork components using ladders, and analyzed five operations by two mechanical contractors. Using continuous time observational assessment, the videotaped operations were analyzed along two dimensions: (1) the production tasks and durations, and (2) the ergonomic demands for four body regions (neck, arms/shoulders, back, and knees). The analysis identified tasks with low portion of productive time and high portion of extreme postures, and task parameters that generated extreme postures. Duct alignment was the task with the highest portion of extreme postures. The position of the ladder (angle and distance from the duct) was a task parameter that strongly influenced the extreme postures for back, neck and shoulders. Other contributing factors included the difficulty to reach the hand tools when working on the ladder, the congestion of components in the ceiling, and the space between the duct and the ceiling. The identified tasks and factors provide directions for improvement.

  5. Dealing with Prospective Memory Demands While Performing an Ongoing Task: Shared Processing, Increased On-Task Focus, or Both?

    Science.gov (United States)

    Rummel, Jan; Smeekens, Bridget A.; Kane, Michael J.

    2017-01-01

    Prospective memory (PM) is the cognitive ability to remember to fulfill intended action plans at the appropriate future moment. Current theories assume that PM fulfillment draws on attentional processes. Accordingly, pending PM intentions interfere with other ongoing tasks to the extent to which both tasks rely on the same processes. How do people…

  6. Effects of task demands on the early neural processing of fearful and happy facial expressions.

    Science.gov (United States)

    Itier, Roxane J; Neath-Tavares, Karly N

    2017-05-15

    Task demands shape how we process environmental stimuli but their impact on the early neural processing of facial expressions remains unclear. In a within-subject design, ERPs were recorded to the same fearful, happy and neutral facial expressions presented during a gender discrimination, an explicit emotion discrimination and an oddball detection tasks, the most studied tasks in the field. Using an eye tracker, fixation on the face nose was enforced using a gaze-contingent presentation. Task demands modulated amplitudes from 200 to 350ms at occipito-temporal sites spanning the EPN component. Amplitudes were more negative for fearful than neutral expressions starting on N170 from 150 to 350ms, with a temporo-occipital distribution, whereas no clear effect of happy expressions was seen. Task and emotion effects never interacted in any time window or for the ERP components analyzed (P1, N170, EPN). Thus, whether emotion is explicitly discriminated or irrelevant for the task at hand, neural correlates of fearful and happy facial expressions seem immune to these task demands during the first 350ms of visual processing. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Stress reactions to cognitively demanding tasks and open-plan office noise

    DEFF Research Database (Denmark)

    Kristiansen, Jesper; Mathiesen, Line; Nielsen, Pernille Kofoed

    2009-01-01

    measured. RESULTS: Cognitively demanding work tasks were associated with changes in HRV, systolic blood pressure and EMG that reflects increased sympathetic activity in the autonomic nervous system. No effect of noise was observed, except for a higher rating of perceived exertion in the head and, contrary......OBJECTIVES: To investigate the effects of cognitively demanding work tasks and office noise on heart rate variability (HRV), cardiovascular responses and electromyography (EMG) activity in the trapezius muscles. METHODS: Ten female volunteers were exposed to simulated open-plan office noise for 35...

  8. Visual Task Demands and the Auditory Mismatch Negativity: An Empirical Study and a Meta-Analysis.

    Science.gov (United States)

    Wiens, Stefan; Szychowska, Malina; Nilsson, Mats E

    2016-01-01

    Because the auditory system is particularly useful in monitoring the environment, previous research has examined whether task-irrelevant, auditory distracters are processed even if subjects focus their attention on visual stimuli. This research suggests that attentionally demanding visual tasks decrease the auditory mismatch negativity (MMN) to simultaneously presented auditory distractors. Because a recent behavioral study found that high visual perceptual load decreased detection sensitivity of simultaneous tones, we used a similar task (n = 28) to determine if high visual perceptual load would reduce the auditory MMN. Results suggested that perceptual load did not decrease the MMN. At face value, these nonsignificant findings may suggest that effects of perceptual load on the MMN are smaller than those of other demanding visual tasks. If so, effect sizes should differ systematically between the present and previous studies. We conducted a selective meta-analysis of published studies in which the MMN was derived from the EEG, the visual task demands were continuous and varied between high and low within the same task, and the task-irrelevant tones were presented in a typical oddball paradigm simultaneously with the visual stimuli. Because the meta-analysis suggested that the present (null) findings did not differ systematically from previous findings, the available evidence was combined. Results of this meta-analysis confirmed that demanding visual tasks reduce the MMN to auditory distracters. However, because the meta-analysis was based on small studies and because of the risk for publication biases, future studies should be preregistered with large samples (n > 150) to provide confirmatory evidence for the results of the present meta-analysis. These future studies should also use control conditions that reduce confounding effects of neural adaptation, and use load manipulations that are defined independently from their effects on the MMN.

  9. Visual Task Demands and the Auditory Mismatch Negativity: An Empirical Study and a Meta-Analysis

    Science.gov (United States)

    Wiens, Stefan; Szychowska, Malina; Nilsson, Mats E.

    2016-01-01

    Because the auditory system is particularly useful in monitoring the environment, previous research has examined whether task-irrelevant, auditory distracters are processed even if subjects focus their attention on visual stimuli. This research suggests that attentionally demanding visual tasks decrease the auditory mismatch negativity (MMN) to simultaneously presented auditory distractors. Because a recent behavioral study found that high visual perceptual load decreased detection sensitivity of simultaneous tones, we used a similar task (n = 28) to determine if high visual perceptual load would reduce the auditory MMN. Results suggested that perceptual load did not decrease the MMN. At face value, these nonsignificant findings may suggest that effects of perceptual load on the MMN are smaller than those of other demanding visual tasks. If so, effect sizes should differ systematically between the present and previous studies. We conducted a selective meta-analysis of published studies in which the MMN was derived from the EEG, the visual task demands were continuous and varied between high and low within the same task, and the task-irrelevant tones were presented in a typical oddball paradigm simultaneously with the visual stimuli. Because the meta-analysis suggested that the present (null) findings did not differ systematically from previous findings, the available evidence was combined. Results of this meta-analysis confirmed that demanding visual tasks reduce the MMN to auditory distracters. However, because the meta-analysis was based on small studies and because of the risk for publication biases, future studies should be preregistered with large samples (n > 150) to provide confirmatory evidence for the results of the present meta-analysis. These future studies should also use control conditions that reduce confounding effects of neural adaptation, and use load manipulations that are defined independently from their effects on the MMN. PMID:26741815

  10. What is difficult for you can be easy for me. Effects of increasing individual task demand on prefrontal lateralization: A tDCS study.

    Science.gov (United States)

    Vergallito, Alessandra; Romero Lauro, Leonor J; Bonandrini, Rolando; Zapparoli, Laura; Danelli, Laura; Berlingeri, Manuela

    2018-01-31

    Neuroimaging studies suggest that the increment of the cognitive load associated with a specific task may induce the recruitment of a more bilateral brain network. In most studies, however, task demand has been manipulated in a static and pre-specified way, regardless of individual cognitive resources. Here we implemented a new paradigm based on a pre-experimental assessment to set up subject-specific levels of task demand and applied tDCS (transcranial direct current stimulation) to assess each hemisphere involvement in task performance. 24 young participants performed a digit span backward (DSB, complex cognitive function) and a paced finger tapping task (pFT, basic motor function) at 3 levels of subject-specific task demand ("low" 5/5 correct answers, "medium" 3/5, "high" 1/5). Anodal tDCS (20min, 1.5mA) was delivered through a target electrode (5 × 5cm) positioned to stimulate both the inferior frontal gyrus and the primary motor area over left and right hemisphere and in sham condition in three different days. A 3 (left, right, sham) × 3 (low, medium, high) mixed-model with random intercept for subjects was run with R software. As expected, in both tasks accuracy decreased with the increment of subject-specific task demand. Moreover, a significant interaction between type of stimulation and subject-specific task demand was found for the reaction times recorded during the DSB and for the accuracy in the pFT: in the most demanding conditions, right anodal tDCS significantly interfered with behavioural performance. Our results suggest that hemispheric lateralization is modulated by the subject-specific level of task demand and this modulation is not task-specific. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. The Language of Children with Spina Bifida and Hydrocephalus: Meeting Task Demands and Mastering Syntax.

    Science.gov (United States)

    Byrne, Karen; And Others

    1990-01-01

    Linguistic performance of 7 children (mean age=68 months) with spina bifida, hydrocephalus, and average intelligence was evaluated. Subjects dealt with the semantic-pragmatic requirements of linguistically posed problems in an age-appropriate manner. Performance declined as task demands increased but no more than performance of nondisabled…

  12. A Software Environment for an Adaptive Human-Aware Software Agent Supporting Attention-Demanding Tasks

    NARCIS (Netherlands)

    Bosse, T.; Memon, Z.A.; Oorburg, R.; Umair, M.; Treur, J.; de Vos, M.

    2011-01-01

    This paper presents a software environment providing human-aware ambient support for a human performing a task that demands substantial amounts of attention. The agent obtains human attention-awareness in an adaptive manner by use of a dynamical model of human attention, gaze sensoring by an

  13. Disentangling longitudinal relations between physical activity, work-related fatigue, and task demands

    NARCIS (Netherlands)

    Vries, J.D. de; Claessens, B.J.C.; Hooff, M.L.M. van; Geurts, S.A.E.; Bossche, S.N.J. van den; Kompier, A.J.

    2016-01-01

    Purpose This longitudinal study examined ‘normal’, ‘reversed’, and ‘reciprocal’ relationships between (1) physical activity and work-related fatigue; and (2) physical activity and task demands. Furthermore, the effects of across-time change in meaningful physical activity groups on levels of

  14. Attention demanding tasks during treadmill walking reduce step width variability in young adults

    Directory of Open Access Journals (Sweden)

    Troy Karen L

    2005-08-01

    Full Text Available Abstract Background The variability of step time and step width is associated with falls by older adults. Further, step time is significantly influenced when performing attention demanding tasks while walking. Without exception, step time variability has been reported to increase in normal and pathologically aging older adults. Because of the role of step width in managing frontal plane dynamic stability, documenting the influence of attention-demanding tasks on step width variability may provide insight to events that can disturb dynamic stability during locomotion and increase fall risk. Preliminary evidence suggests performance of an attention demanding task significantly decreases step width variability of young adults walking on a treadmill. The purpose of the present study was to confirm or refute this finding by characterizing the extent and direction of the effects of a widely used attention demanding task (Stroop test on the step width variability of young adults walking on a motorized treadmill. Methods Fifteen healthy young adults walked on a motorized treadmill at a self-selected velocity for 10 minutes under two conditions; without performing an attention demanding task and while performing the Stroop test. Step width of continuous and consecutive steps during the collection was derived from the data recorded using a motion capture system. Step width variability was computed as the standard deviation of all recorded steps. Results Step width decreased four percent during performance of the Stroop test but the effect was not significant (p = 0.10. In contrast, the 16 percent decrease in step width variability during the Stroop test condition was significant (p = 0.029. Conclusion The results support those of our previous work in which a different attention demanding task also decreased step width variability of young subjects while walking on a treadmill. The decreased step width variability observed while performing an attention

  15. Brain biomarkers based assessment of cognitive workload in pilots under various task demands.

    Science.gov (United States)

    Gentili, Rodolphe J; Rietschel, Jeremy C; Jaquess, Kyle J; Lo, Li-Chuan; Prevost, Michael; Miller, Matt W; Mohler, Jessica M; Oh, Hyuk; Tan, Ying Ying; Hatfield, Bradley D

    2014-01-01

    Cognitive workload is an important element of cognitive-motor performance such as that exhibited during the piloting of an aircraft. Namely, an increase in task demands on the pilot can elevate cognitive information processing and, thus, the risk of human error. As such, there is a need to develop methods that reliably assess mental workload in pilots within operational settings. The present study contributes to this research goal by identifying physiological and brain biomarkers of cognitive workload and attentional reserve during a simulated aircraft piloting task under three progressive levels of challenge. A newly developed experimental method was employed by which electroencephalography (EEG) was acquired via a dry (i.e., gel-free sensors) system using few scalp sites. Self-reported responses to surveys and piloting performance indicators were analyzed. The findings revealed that as the challenge (task demands) increased, the perceived mental load increased, attentional reserve was attenuated, and task performance decreased. Such an increase in task demands was also reflected by changes in heart rate variability (HRV), as well as in the amplitude of the P300 component of event-related potentials to auditory probes, and in the spectral power of specific EEG frequency bands. This work provides a first step towards a long-term goal to develop a composite system of biomarkers for real-time cognitive workload assessment and state assessment of pilots in operational settings.

  16. Professional development in statistics, technology, and cognitively demanding tasks: classroom implementation and obstacles

    Science.gov (United States)

    Foley, Gregory D.; Bakr Khoshaim, Heba; Alsaeed, Maha; Nihan Er, S.

    2012-03-01

    Attending professional development programmes can support teachers in applying new strategies for teaching mathematics and statistics. This study investigated (a) the extent to which the participants in a professional development programme subsequently used the techniques they had learned when teaching mathematics and statistics and (b) the obstacles they encountered in enacting cognitively demanding instructional tasks in their classrooms. The programme created an intellectual learning community among the participants and helped them gain confidence as teachers of statistics, and the students of participating teachers became actively engaged in deep mathematical thinking. The participants indicated, however, that time, availability of resources and students' prior achievement critically affected the implementation of cognitively demanding instructional activities.

  17. Computerized assessment of sustained attention: interactive effects of task demand, noise, and anxiety.

    Science.gov (United States)

    Ballard, J C

    1996-12-01

    In a sample of 163 college undergraduates, the effects of task demand, noise, and anxiety on Continuous Performance Test (CPT) errors were evaluated with multiple regression and multivariate analysis of variance. Results indicated significantly more omission errors on the difficult task. Complex interaction effects of noise and self-reported anxiety yielded more omissions in quiet intermittent white noise, particularly for high-anxious subjects performing the difficult task. Anxiety levels tended to increase from pretest to posttest, particularly for low-anxious subjects in the quiet, difficult-task condition, while a decrease was seen for high-anxious subjects in the loud, easy-task condition. Commission errors were unrelated to any predictor variables, suggesting that "attention" cannot be considered a unitary phenomenon. The variety of direct and interactive effects on vigilance performance underscore the need for clinicians to use a variety of measures to assess attentional skills, to avoid diagnosis of attention deficits on the basis of a single computerized task performance, and to rule out anxiety and other contributors to poor vigilance task performance.

  18. Surface feature congruency effects in the object-reviewing paradigm are dependent on task memory demands.

    Science.gov (United States)

    Kimchi, Ruth; Pirkner, Yossef

    2014-08-01

    Perception of object continuity depends on establishing correspondence between objects viewed across disruptions in visual information. The role of spatiotemporal information in guiding object continuity is well documented; the role of surface features, however, is controversial. Some researchers have shown an object-specific preview benefit (OSPB)-a standard index of object continuity-only when correspondence could be based on an object's spatiotemporal information, whereas others have found color-based OSPB, suggesting that surface features can also guide object continuity. This study shows that surface feature-based OSPB is dependent on the task memory demands. When the task involved letters and matching just one target letter to the preview ones, no color congruency effect was found under spatiotemporal discontinuity and spatiotemporal ambiguity (Experiments 1-3), indicating that the absence of feature-based OSPB cannot be accounted for by salient spatiotemporal discontinuity. When the task involved complex shapes and matching two target shapes to the preview ones, color-based OSPB was obtained. Critically, however, when a visual working memory task was performed concurrently with the matching task, the presence of a nonspatial (but not a spatial) working memory load eliminated the color-based OSPB (Experiments 4 and 5). These results suggest that the surface feature congruency effects that are observed in the object-reviewing paradigm (with the matching task) reflect memory-based strategies that participants use to solve a memory-demanding task; therefore, they are not reliable measures of online object continuity and cannot be taken as evidence for the role of surface features in establishing object correspondence.

  19. Task demands affect spatial reference frame weighting during tactile localization in sighted and congenitally blind adults

    OpenAIRE

    Heed, Tobias; Roeder, Brigitte; Badde, Stephanie; Schubert, Jonathan

    2017-01-01

    Task demands modulate tactile localization in sighted humans, presumably through weight adjustments in the spatial integration of anatomical, skin-based, and external, posture-based information. In contrast, previous studies have suggested that congenitally blind humans, by default, refrain from automatic spatial integration and localize touch using only skin-based information. Here, sighted and congenitally blind participants localized tactile targets on the palm or back of one hand, while i...

  20. The Effects of Task Demand and External Stimuli on Learner's Stress Perception and Performance

    OpenAIRE

    Lim, Yee Mei; Ayesh, Aladdin, 1972-; Stacey, Martin; Tan, Li Peng

    2016-01-01

    Over the past decades, research in e-learning has begun to take emotions into account, which is also known as affective learning. It advocates an education system that is sentient of learner's cognitive and affective states, as learners' performance could be affected by emotional factors. This exploratory research examines the impacts of task demand and external stimuli on learner's stress perception and job performance. Experiments are conducted on 160 undergraduate students from a higher le...

  1. Change in Thinking Demands for Students Across the Phases of a Science Task: An Exploratory Study

    Science.gov (United States)

    Tekkumru-Kisa, Miray; Schunn, Christian; Stein, Mary Kay; Reynolds, Bertha

    2017-08-01

    Science education communities around the world have increasingly emphasized engaging students in the disciplinary practices of science as they engage in high levels of reasoning about scientific ideas. Consistently, this is a critical moment in time in the USA as it goes through a new wave of science education reform within the context of Next Generation Science Standards (NGSS). We argue that the placement of high demands on students' thinking (i.e., a high level of thinking) in combination with positioning students to use disciplinary practices as they try to make sense of scientific ideas (i.e., a deep kind of thinking) constitute critical aspects of the reform. The main purpose of this paper is to identify and describe the kinds and levels of thinking in which students engage when they are invited to think and reason as demanded by NGSS-aligned curricular tasks. Our analysis of video records of classrooms in which an NGSS-aligned, cognitively demanding task was used, revealed many ways in which the aspirational level and kind of student thinking will not be met in many science classrooms. We propose a way of characterizing and labeling the differences among these kinds and levels of thinking during the implementation of a reform-based biology curriculum. These categories, which focus on two important features emphasized in the NGSS, can help us to better understand, diagnose, and communicate issues during the implementation of high-level tasks in science classrooms.

  2. Investigating the Effects of Concurrent Performance of Physical and Cognitive Demanding Task in Paced Assembly Lines

    Directory of Open Access Journals (Sweden)

    Shakil Ahmed Shaikh

    2013-07-01

    Full Text Available The study was undertaken to investigate the effects of pacing on aspects of performance at an assembly task and on the operators' responses related to work behaviour, perceived workload and perceived stress. A particular objective of the study was to investigate whether physical and cognitive demands may interact in their influences on these effects. An assembly task was simulated in the laboratory and the level of pacing imposed, work height and memory load within the task were all varied. The results showed that the type of pacing commonly imposed (as is common with a lean manufacturing Takt time system in industry can significantly affect both performance and perceived workload and stress. Physical demands (through work height affecting posture and mental demand (through memory load were also found to have significant effects, as would be expected from the many studies of these in the literature. More importantly, some interactions were found between pacing and work height in their effects on quality of assembly and the operator's own rating of performance, and between work height and memory load in their effects on errors. These findings will need to be taken into account by companies when implementing Takt time systems.

  3. Eldercare demands, mental health, and work performance: the moderating role of satisfaction with eldercare tasks.

    Science.gov (United States)

    Zacher, Hannes; Jimmieson, Nerina L; Winter, Gabriele

    2012-01-01

    Due to demographic changes, a growing number of employees provide in-home care to an elderly family member. Previous research suggested a negative relationship between employees' eldercare demands and their work performance. However, the empirical nature of this relationship and its boundary conditions and mediating mechanisms have been neglected. The goal of this multisource study was to examine a mediated-moderation model of eldercare demands, mental health, and work performance. Drawing on the theory of conservation of resources (Hobfoll, 1989), it was expected that employees' satisfaction with eldercare tasks would buffer the negative relationship between eldercare demands and work performance, and that mental health would mediate this moderating effect. Data were collected from 165 employees providing in-home eldercare, as well as from one colleague and one family member of each employee. Results of mediated-moderation analyses supported the hypothesized model. The findings suggest that interventions that aim to increase employees' satisfaction with eldercare tasks may help protect employees from the negative effects of high eldercare demands on mental health and, subsequently, on work performance.

  4. Identifying the critical physical demanding tasks of paramedic work: Towards the development of a physical employment standard.

    Science.gov (United States)

    Fischer, Steven L; Sinden, Kathryn E; MacPhee, Renee S

    2017-11-01

    Public safety related occupations including police, fire and military commonly apply physical employment standard (PES) to facilitate job matching, an approach to evaluate if candidates demonstrate acceptable physical capabilities as required to perform the job safely and effectively. In Canada, paramedics remain as one of the few public safety occupations without an evidence-based, validated PES. The purpose of this study was to document and describe the physical demands of paramedic work and to identify the most physically demanding tasks. These outcomes are essential to inform the design and development of an evidence-based PES for the paramedic sector. Physical demands of paramedic work were documented and described using a direct observation-based task analysis technique. Five paramedic's were trained to document the physical demands of their work, then applied their training to observe more than 90 calls over the course of 20 full 12-h work shifts. Physical demands data were then listed in a survey, administered service-wide, where 155 frontline paramedics identified critically demanding tasks and rank-ordered physical demands from not physically demanding to very strongly demanding. Critically important and physically demanding tasks were identified such as: transferring a patient; loading or unloading a stretcher in to or out of the ambulance; performing CPR; and, raising and lowering a stretcher. It is important that a paramedic-based PES evaluate a candidate's physical capabilities to perform the critical and physically demanding tasks identified in this study. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Perception and action de-coupling in congenital amusia: sensitivity to task demands.

    Science.gov (United States)

    Williamson, Victoria J; Liu, Fang; Peryer, Guy; Grierson, Mick; Stewart, Lauren

    2012-01-01

    Theories that purport the existence of a distinct auditory action stream have received support from the finding that individuals with congenital amusia, a disorder of pitch perception, are able to reproduce the direction of a pitch change that they are unable to identify (Loui, Guenther, Mathys, & Schlaug, 2008). Although this finding has proved influential in theorizing about the existence of an auditory action-stream, aspects of the original study warrant further investigation. The present report attempts to replicate the original study's findings across a sizeable cohort of individuals with amusia (n=14), obtaining action (production) and perception thresholds for pitch direction. In contrast to the original study, we find evidence of a double dissociation: while a minority of amusics had lower (better) thresholds for production compared to perception of pitch, more than half showed the reverse pattern. To explore the impact of task demands, perception thresholds were also measured using a two alternative, criterion-free, forced choice task that avoided labeling demands. Controls' thresholds were task-invariant while amusics' thresholds were significantly task-dependent. We argue that the direction and extent of a perception/production dissociation in this population reflects individual differences in the mapping of pitch representations to labels ("up"; "down") and to the vocal apparatus, as opposed to anything intrinsically yoked to perception or action per se. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Attentional Capture by Salient Distractors during Visual Search Is Determined by Temporal Task Demands

    DEFF Research Database (Denmark)

    Kiss, Monika; Grubert, Anna; Petersen, Anders

    2012-01-01

    The question whether attentional capture by salient but taskirrelevant visual stimuli is triggered in a bottom–up fashion or depends on top–down task settings is still unresolved. Strong support for bottom–up capture was obtained in the additional singleton task, in which search arrays were visible...... until response onset. Equally strong evidence for top–down control of attentional capture was obtained in spatial cueing experiments in which display durations were very brief. To demonstrate the critical role of temporal task demands on salience-driven attentional capture, we measured ERP indicators...... component that was followed by a late Pd component, suggesting that they triggered attentional capture, which was later replaced by location-specific inhibition. When search arrays were visible for only 200 msec, the distractor-elicited N2pc was eliminated and was replaced by a Pd component in the same time...

  7. Public Relations in Contemporary India: Current Demands and Strategy.

    Science.gov (United States)

    Singh, Raveena

    2000-01-01

    Discusses India's new direction and the persistent and insistent demand for public relations. Explains the strategic plan of the professional body in running the gauntlet in this new milieu and the pertinaciousness and urgency of the challenges ahead for public relations. (SC)

  8. Demand Response Within Current Electricity Wholesale Market Design

    OpenAIRE

    Ramos Gutierrez, Ariana Isabel; De Jonghe, Cedric; Six, Daan; Belmans, Ronnie

    2013-01-01

    The introduction of intermittent energy resources calls for the ability to modulate consumption patterns according to electricity availability. This paper provides a brief overview of the main electricity market design characteristics and places demand response within the framework of the existing timeline of market operation. The main differences between electricity markets lie in the price formation mechanisms where some markets pay-as- cleared and some pay- as- bid for the electricity tran...

  9. Emotion, working memory task demands and individual differences predict behavior, cognitive effort and negative affect.

    Science.gov (United States)

    Storbeck, Justin; Davidson, Nicole A; Dahl, Chelsea F; Blass, Sara; Yung, Edwin

    2015-01-01

    We examined whether positive and negative affect motivates verbal and spatial working memory processes, respectively, which have implications for the expenditure of mental effort. We argue that when emotion promotes cognitive tendencies that are goal incompatible with task demands, greater cognitive effort is required to perform well. We sought to investigate whether this increase in cognitive effort impairs behavioural control over a broad domain of self-control tasks. Moreover, we predicted that individuals with higher behavioural inhibition system (BIS) sensitivities would report more negative affect within the goal incompatible conditions because such individuals report higher negative affect during cognitive challenge. Positive or negative affective states were induced followed by completing a verbal or spatial 2-back working memory task. All participants then completed one of three self-control tasks. Overall, we observed that conditions of emotion and working memory incompatibility (positive/spatial and negative/verbal) performed worse on the self-control tasks, and within the incompatible conditions individuals with higher BIS sensitivities reported more negative affect at the end of the study. The combination of findings suggests that emotion and working memory compatibility reduces cognitive effort and impairs behavioural control.

  10. Nicotine-induced enhancement of attention in the five-choice serial reaction time task: the influence of task demands.

    Science.gov (United States)

    Hahn, B; Shoaib, M; Stolerman, I P

    2002-07-01

    Beneficial effects of nicotine on cognitive processes including attention have potential therapeutic uses and have been proposed as incentives for tobacco smoking. To establish task conditions under which the effects of nicotine on attention are obtained reliably and to characterise such effects further. Rats were trained in a modified version of the five-choice serial reaction time task (5-CSRTT) to detect 1-s light stimuli with greater than 70% accuracy and fewer than 20% omission errors. Nicotine was tested under different task requirements by varying signal event rate, stimulus duration and stimulus predictability, and by introducing white-noise distractors. Nicotine (0.05-0.2 mg/kg, s.c.) repeatedly improved accuracy and reduced omission errors and reaction times, leading to increases in numbers of reinforcers earned. Anticipatory responding was increased. Parametric modifications intended to increase demands on sustained attention did not affect performance in a manner suggesting that this subtype of attention was being taxed, and the effects of nicotine were not more marked under such conditions. Shorter stimulus durations impaired performance, but this manipulation weakened the effect of nicotine on accuracy. In contrast, the presence of noise distractors facilitated the effects of nicotine to the extent that distractor-induced impairments were abolished by the drug. The 5-CSRTT can provide a sensitive rodent model for the attention-enhancing effects of nicotine. Changes made to the procedure may have increased its sensitivity to nicotine, particularly with respect to accuracy. There were indications that the effects of nicotine were largest on processes of selective attention or on disengaging attention from irrelevant events and shifting it to behaviourally significant stimuli.

  11. Demand characteristics, pre-test attitudes and time-on-task trends in the effects of chewing gum on attention and reported mood in healthy volunteers.

    Science.gov (United States)

    Allen, A P; Smith, A P

    2012-10-01

    Previous research has indicated that chewing gum enhances reported alertness, but has variable effects on attention. Demand characteristics may explain these effects. The current study investigated the effects of gum and demand characteristics on attention and reported mood over time. Participants completed measures of mood and attention, with and without chewing gum. To manipulate demand characteristics, they were told that the hypothesised effect of gum was either positive or negative, or no hypothesis was mentioned. Attitudes towards gum were assessed pre- and post-manipulation. Gum increased reported alertness; this effect was only significant for positive and neutral demand characteristics. Vigilance accuracy was reduced for chewing gum, but only in the fourth minute of the task, and gum reduced focussed attention accuracy, but only for the first 64 trials. Demand characteristics did not moderate time-on-task effects. Gum improved selective attention. A positive effect on response organisation was observed; this was significant when demand characteristics and pre-test attitudes to gum were both negative. The results suggest that demand characteristics moderate effects on self-reported alertness and response organisation, but cannot explain time-on-task effects or variable main effects on other aspects of attention. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. 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.

  13. Current supply and demand of veterinarians in Japan

    Directory of Open Access Journals (Sweden)

    Katsuaki Sugiura

    2008-06-01

    Full Text Available Since 1966, approximately 1 000 veterinarians graduate each year from 16 veterinary schools in Japan. According to reports submitted by veterinarians to the Ministry of Agriculture, Forestry and Fisheries in January 2007, there were over 35 818 veterinarians in Japan at the end of 2006. Of this total, 13 202 (36.8% were engaged in companion animal practice, 9 112 (25.4% were civil servants and 4 180 (11.7% were engaged in food animal practice. The total number of veterinarians has increased gradually over the past 40 years. Recently, the number of veterinarians engaged in companion animal practice has increased while the number of veterinarians engaged in food animal practice is declining. These trends reflect the change in demand for veterinarians in food and companion animal practice, resulting mainly from changes in the number of food animals and companion animals in recent years. The number of veterinarians in the public sector has decreased gradually due to the administrative reforms of recent years.

  14. When global rule reversal meets local task switching: The neural mechanisms of coordinated behavioral adaptation to instructed multi-level demand changes.

    Science.gov (United States)

    Shi, Yiquan; Wolfensteller, Uta; Schubert, Torsten; Ruge, Hannes

    2018-02-01

    Cognitive flexibility is essential to cope with changing task demands and often it is necessary to adapt to combined changes in a coordinated manner. The present fMRI study examined how the brain implements such multi-level adaptation processes. Specifically, on a "local," hierarchically lower level, switching between two tasks was required across trials while the rules of each task remained unchanged for blocks of trials. On a "global" level regarding blocks of twelve trials, the task rules could reverse or remain the same. The current task was cued at the start of each trial while the current task rules were instructed before the start of a new block. We found that partly overlapping and partly segregated neural networks play different roles when coping with the combination of global rule reversal and local task switching. The fronto-parietal control network (FPN) supported the encoding of reversed rules at the time of explicit rule instruction. The same regions subsequently supported local task switching processes during actual implementation trials, irrespective of rule reversal condition. By contrast, a cortico-striatal network (CSN) including supplementary motor area and putamen was increasingly engaged across implementation trials and more so for rule reversal than for nonreversal blocks, irrespective of task switching condition. Together, these findings suggest that the brain accomplishes the coordinated adaptation to multi-level demand changes by distributing processing resources either across time (FPN for reversed rule encoding and later for task switching) or across regions (CSN for reversed rule implementation and FPN for concurrent task switching). © 2017 Wiley Periodicals, Inc.

  15. Behavioral Economic Purchase Tasks to Estimate Demand for Novel Nicotine/Tobacco Products and Prospectively Predict Future Use: Evidence from the Netherlands.

    Science.gov (United States)

    Heckman, Bryan W; Cummings, K Michael; Nahas, Georges J; Willemsen, Marc C; O'Connor, Richard J; Borland, Ron; Hirsch, Alexander A; Bickel, Warren K; Carpenter, Matthew J

    2018-03-14

    The demand for alternative nicotine/tobacco products is not well established. This paper uses a behavioral economic approach to test whether smokers have differential demand for conventional factory-made, electronic, and very low nicotine content cigarettes (FMCs/ECs/VLNCs) and uses the prospective cohort design to test the predictive validity of demand indices on subsequent use of commercially available FMCs and ECs. Daily smokers (>16 years) from the Netherlands completed an online survey in April 2014 (N=1215). Purchase tasks were completed for FMCs, ECs, and VLNCs. Participants indicated the number of cigarettes they would consume in 24 hours, across a range of prices (0-30 euro). The relationship between consumption and price was quantified into four indices of demand (intensity, Pmax, breakpoint, and essential value). A follow-up survey in July 2015 measured FMC and EC use. At baseline, greater demand was observed for FMCs relative to ECs and VLNCs across all demand indices, with no difference between ECs and VLNCs. At follow-up, greater baseline FMC demand (intensity, essential value) was associated with lower quit rates and higher relapse. EC demand (Pmax, breakpoint, essential value) was positively associated with any EC use between survey waves, past 30 day EC use, and EC purchase between waves. Smokers valued FMCs more than ECs or VLNCs, and FMCs were less sensitive to price increases. Demand indices predicted use of commercially available products over a 15 month period. To serve as viable substitutes for FMCs, ECs and VLNCs will need to be priced lower than FMCs. Purchase tasks can be adapted for novel nicotine/tobacco products as a means to efficiently quantify demand and predict use. Among current daily smokers, the demand for ECs and VLNCs is lower than FMCs.

  16. Higher balance task demands are associated with an increase in individual alpha peak frequency

    Directory of Open Access Journals (Sweden)

    Thorben eHülsdünker

    2016-01-01

    Full Text Available Balance control is fundamental for most daily motor activities, and its impairment is associated with an increased risk of falling. Growing evidence suggests the human cortex is essentially contributing to the control of standing balance. However, the exact mechanisms remain unclear and need further investigation. In a previous study we introduced a new protocol to identify electrocortical activity associated with performance of different continuous balance tasks with the eyes opened. The aim of this study was to extend our previous results by investigating the individual alpha peak frequency (iAPF, a neurophysiological marker of thalamo-cortical information transmission, which remained unconsidered so far in balance research. Thirty-seven subjects completed nine balance tasks varying in surface stability and base of support. Electroencephalography (EEG was recorded from 32 scalp locations throughout balancing with the eyes closed to ensure reliable identification of the iAPF. Balance performance was quantified as the sum of anterior-posterior and medio-lateral movements of the supporting platform. The iAPF, as well as power in the theta, lower alpha and upper alpha frequency bands were determined for each balance task after applying an ICA-based artifact rejection procedure. Higher demands on balance control were associated with a global increase in iAPF and a decrease in lower alpha power. These results may indicate increased thalamo-cortical information transfer and general cortical activation, respectively. In addition, a significant increase in upper alpha activity was observed in the fronto-central region whereas it decreased in the centro-parietal region. Furthermore, midline theta increased with higher task demands probably indicating activation of error detection/processing mechanisms. IAPF as well as theta and alpha power were correlated with platform movements. The results provide new insights into spectral and spatial characteristics

  17. Modulation of the electrophysiological correlates of retrieval cue processing by the specificity of task demands.

    Science.gov (United States)

    Johnson, Jeffrey D; Rugg, Michael D

    2006-02-03

    Retrieval orientation refers to the differential processing of retrieval cues according to the type of information sought from memory (e.g., words vs. pictures). In the present study, event-related potentials (ERPs) were employed to investigate whether the neural correlates of differential retrieval orientations are sensitive to the specificity of the retrieval demands of the test task. In separate study-test phases, subjects encoded lists of intermixed words and pictures, and then undertook one of two retrieval tests, in both of which the retrieval cues were exclusively words. In the recognition test, subjects performed 'old/new' discriminations on the test items, and old items corresponded to only one class of studied material (words or pictures). In the exclusion test, old items corresponded to both classes of study material, and subjects were required to respond 'old' only to test items corresponding to a designated class of material. Thus, demands for retrieval specificity were greater in the exclusion test than during recognition. ERPs elicited by correctly classified new items in the two types of test were contrasted according to whether words or pictures were the sought-for material. Material-dependent ERP effects were evident in both tests, but the effects onset earlier and offset later in the exclusion test. The findings suggest that differential processing of retrieval cues, and hence the adoption of differential retrieval orientations, varies according to the specificity of the retrieval goal.

  18. The influence of an auditory-memory attention-demanding task on postural control in blind persons.

    Science.gov (United States)

    Melzer, Itshak; Damry, Elad; Landau, Anat; Yagev, Ronit

    2011-05-01

    In order to evaluate the effect of an auditory-memory attention-demanding task on balance control, nine blind adults were compared to nine age-gender-matched sighted controls. This issue is particularly relevant for the blind population in which functional assessment of postural control has to be revealed through "real life" motor and cognitive function. The study aimed to explore whether an auditory-memory attention-demanding cognitive task would influence postural control in blind persons and compare this with blindfolded sighted persons. Subjects were instructed to minimize body sway during narrow base upright standing on a single force platform under two conditions: 1) standing still (single task); 2) as in 1) while performing an auditory-memory attention-demanding cognitive task (dual task). Subjects in both groups were required to stand blindfolded with their eyes closed. Center of Pressure displacement data were collected and analyzed using summary statistics and stabilogram-diffusion analysis. Blind and sighted subjects had similar postural sway in eyes closed condition. However, for dual compared to single task, sighted subjects show significant decrease in postural sway while blind subjects did not. The auditory-memory attention-demanding cognitive task had no interference effect on balance control on blind subjects. It seems that sighted individuals used auditory cues to compensate for momentary loss of vision, whereas blind subjects did not. This may suggest that blind and sighted people use different sensorimotor strategies to achieve stability. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. Task demands affect spatial reference frame weighting during tactile localization in sighted and congenitally blind adults.

    Directory of Open Access Journals (Sweden)

    Jonathan T W Schubert

    Full Text Available Task demands modulate tactile localization in sighted humans, presumably through weight adjustments in the spatial integration of anatomical, skin-based, and external, posture-based information. In contrast, previous studies have suggested that congenitally blind humans, by default, refrain from automatic spatial integration and localize touch using only skin-based information. Here, sighted and congenitally blind participants localized tactile targets on the palm or back of one hand, while ignoring simultaneous tactile distractors at congruent or incongruent locations on the other hand. We probed the interplay of anatomical and external location codes for spatial congruency effects by varying hand posture: the palms either both faced down, or one faced down and one up. In the latter posture, externally congruent target and distractor locations were anatomically incongruent and vice versa. Target locations had to be reported either anatomically ("palm" or "back" of the hand, or externally ("up" or "down" in space. Under anatomical instructions, performance was more accurate for anatomically congruent than incongruent target-distractor pairs. In contrast, under external instructions, performance was more accurate for externally congruent than incongruent pairs. These modulations were evident in sighted and blind individuals. Notably, distractor effects were overall far smaller in blind than in sighted participants, despite comparable target-distractor identification performance. Thus, the absence of developmental vision seems to be associated with an increased ability to focus tactile attention towards a non-spatially defined target. Nevertheless, that blind individuals exhibited effects of hand posture and task instructions in their congruency effects suggests that, like the sighted, they automatically integrate anatomical and external information during tactile localization. Moreover, spatial integration in tactile processing is, thus, flexibly

  20. Task demands affect spatial reference frame weighting during tactile localization in sighted and congenitally blind adults.

    Science.gov (United States)

    Schubert, Jonathan T W; Badde, Stephanie; Röder, Brigitte; Heed, Tobias

    2017-01-01

    Task demands modulate tactile localization in sighted humans, presumably through weight adjustments in the spatial integration of anatomical, skin-based, and external, posture-based information. In contrast, previous studies have suggested that congenitally blind humans, by default, refrain from automatic spatial integration and localize touch using only skin-based information. Here, sighted and congenitally blind participants localized tactile targets on the palm or back of one hand, while ignoring simultaneous tactile distractors at congruent or incongruent locations on the other hand. We probed the interplay of anatomical and external location codes for spatial congruency effects by varying hand posture: the palms either both faced down, or one faced down and one up. In the latter posture, externally congruent target and distractor locations were anatomically incongruent and vice versa. Target locations had to be reported either anatomically ("palm" or "back" of the hand), or externally ("up" or "down" in space). Under anatomical instructions, performance was more accurate for anatomically congruent than incongruent target-distractor pairs. In contrast, under external instructions, performance was more accurate for externally congruent than incongruent pairs. These modulations were evident in sighted and blind individuals. Notably, distractor effects were overall far smaller in blind than in sighted participants, despite comparable target-distractor identification performance. Thus, the absence of developmental vision seems to be associated with an increased ability to focus tactile attention towards a non-spatially defined target. Nevertheless, that blind individuals exhibited effects of hand posture and task instructions in their congruency effects suggests that, like the sighted, they automatically integrate anatomical and external information during tactile localization. Moreover, spatial integration in tactile processing is, thus, flexibly adapted by top

  1. Isolating Discriminant Neural Activity in the Presence of Eye Movements and Concurrent Task Demands

    Directory of Open Access Journals (Sweden)

    Jon Touryan

    2017-07-01

    Full Text Available A growing number of studies use the combination of eye-tracking and electroencephalographic (EEG measures to explore the neural processes that underlie visual perception. In these studies, fixation-related potentials (FRPs are commonly used to quantify early and late stages of visual processing that follow the onset of each fixation. However, FRPs reflect a mixture of bottom-up (sensory-driven and top-down (goal-directed processes, in addition to eye movement artifacts and unrelated neural activity. At present there is little consensus on how to separate this evoked response into its constituent elements. In this study we sought to isolate the neural sources of target detection in the presence of eye movements and over a range of concurrent task demands. Here, participants were asked to identify visual targets (Ts amongst a grid of distractor stimuli (Ls, while simultaneously performing an auditory N-back task. To identify the discriminant activity, we used independent components analysis (ICA for the separation of EEG into neural and non-neural sources. We then further separated the neural sources, using a modified measure-projection approach, into six regions of interest (ROIs: occipital, fusiform, temporal, parietal, cingulate, and frontal cortices. Using activity from these ROIs, we identified target from non-target fixations in all participants at a level similar to other state-of-the-art classification techniques. Importantly, we isolated the time course and spectral features of this discriminant activity in each ROI. In addition, we were able to quantify the effect of cognitive load on both fixation-locked potential and classification performance across regions. Together, our results show the utility of a measure-projection approach for separating task-relevant neural activity into meaningful ROIs within more complex contexts that include eye movements.

  2. AAPM/SNMMI Joint Task Force: report on the current state of nuclear medicine physics training

    Science.gov (United States)

    Allison, Jerry D.; Clements, Jessica B.; Coffey, Charles W.; Fahey, Frederic H.; Gress, Dustin A.; Kinahan, Paul E.; Nickoloff, Edward L.; Mawlawi, Osama R.; MacDougall, Robert D.; Pizzuitello, Robert J.

    2015-01-01

    The American Association of Physicists in Medicine (AAPM) and the Society of Nuclear Medicine and Molecular Imaging (SNMMI) recognized the need for a review of the current state of nuclear medicine physics training and the need to explore pathways for improving nuclear medicine physics training opportunities. For these reasons, the two organizations formed a joint AAPM/SNMMI Ad Hoc Task Force on Nuclear Medicine Physics Training. The mission of this task force was to assemble a representative group of stakeholders to: Estimate the demand for board‐certified nuclear medicine physicists in the next 5–10 years,Identify the critical issues related to supplying an adequate number of physicists who have received the appropriate level of training in nuclear medicine physics, andIdentify approaches that may be considered to facilitate the training of nuclear medicine physicists. As a result, a task force was appointed and chaired by an active member of both organizations that included representation from the AAPM, SNMMI, the American Board of Radiology (ABR), the American Board of Science in Nuclear Medicine (ABSNM), and the Commission for the Accreditation of Medical Physics Educational Programs (CAMPEP). The Task Force first met at the AAPM Annual Meeting in Charlotte in July 2012 and has met regularly face‐to‐face, online, and by conference calls. This manuscript reports the findings of the Task Force, as well as recommendations to achieve the stated mission. PACS number: 01.40.G‐ PMID:26699325

  3. Nicotine intake and problem solving strategies are modified during a cognitively demanding water maze task in rats.

    Science.gov (United States)

    Nesil, Tanseli; Kanit, Lutfiye; Pogun, Sakire

    2015-11-01

    Nicotine is the major addictive component in tobacco, and despite well-established adverse health effects of tobacco addiction, some smokers have difficulty quitting. The acute cognitive enhancement and/or the amelioration of the cognitive disruption during withdrawal that some smokers experience after smoking are among important factors that hinder quit attempts. The animal model presented in the current study is comparable to the human smoking condition although nicotine intake routes are different. Rats were exposed to a free choice of oral nicotine starting at adolescence, and given a water maze (WM) task as adults. This design allowed us to see if rats alter their nicotine intake during the WM task and if nicotine preference and intake modify abilities and strategies rats use for problem solving. Male and female rats were exposed to a free choice of oral nicotine/water for 24weeks, starting at five weeks of age. After this period, they were selected based on their nicotine intake and, together with control animals that received only water, were subjected to a place-learning task in the WM. Free-choice nicotine exposure continued during WM testing. Following acquisition, the probe trial presented the rats with a choice between using two different strategies for problem solving. Nicotine supported acquisition and rats increased their nicotine intake during WM testing; this effect was more pronounced in male rats with minimum nicotine preference and intake. Furthermore, nicotine modified the "female type" strategy in solving the place-learning task and nicotine treated female rats, unlike control females, behaved like males. The increase in nicotine intake during mental engagement, and the sexually dimorphic effect of nicotine on problem solving strategies that we have observed in rats, may suggest that implementing sex-specific smoking cessation approaches, especially under stressful and cognitively demanding conditions, may be useful in helping smokers quit

  4. Students and Instant Messaging: Survey on Current Use and Demands for Higher Education

    NARCIS (Netherlands)

    De Bakker, Gijs; Sloep, Peter; Jochems, Wim

    2008-01-01

    De Bakker, G., Sloep, P. B., & Jochems, W. M. G. (2007). Students and instant messaging: survey on current use and demands for higher education. Research in Learning Technology (ALT-J), 15(2), 143-153.

  5. What Do We Really Know about Cognitive Inhibition? Task Demands and Inhibitory Effects across a Range of Memory and Behavioural Tasks.

    Directory of Open Access Journals (Sweden)

    Saima Noreen

    Full Text Available Our study explores inhibitory control across a range of widely recognised memory and behavioural tasks. Eighty-seven never-depressed participants completed a series of tasks designed to measure inhibitory control in memory and behaviour. Specifically, a variant of the selective retrieval-practice and the Think/No-Think tasks were employed as measures of memory inhibition. The Stroop-Colour Naming and the Go/No-Go tasks were used as measures of behavioural inhibition. Participants completed all 4 tasks. Task presentation order was counterbalanced across 3 separate testing sessions for each participant. Standard inhibitory forgetting effects emerged on both memory tasks but the extent of forgetting across these tasks was not correlated. Furthermore, there was no relationship between memory inhibition tasks and either of the main behavioural inhibition measures. At a time when cognitive inhibition continues to gain acceptance as an explanatory mechanism, our study raises fundamental questions about what we actually know about inhibition and how it is affected by the processing demands of particular inhibitory tasks.

  6. Relative effects of demand and control on task-related cardiovascular reactivity, task perceptions, performance accuracy, and mood.

    Science.gov (United States)

    Flynn, Niamh; James, Jack E

    2009-05-01

    The hypothesis that work control has beneficial effects on well-being is the basis of the widely applied, yet inconsistently supported, Job Demand Control (JDC) Model [Karasek, R.A., 1979. Job demands, job decision latitude and mental strain: Implications for job redesign. Adm. Sci. Q. 24, 285-308.; Karasek, R., Theorell, T., 1990. Healthy Work: Stress, Productivity, and the Reconstruction of Working Life. Basic Books, Oxford]. The model was tested in an experiment (N=60) using a cognitive stressor paradigm that sought to prevent confounding between demand and control. High-demand was found to be associated with deleterious effects on physiological, subjective, and performance outcomes. In contrast, few main effects were found for control. Evidence for the buffer interpretation of the JDC Model was limited to a significant demand-control interaction for performance accuracy, whereas substantial support was found for the strain interpretation of the model [van der Doef, M., Maes, S., 1998. The job demand-control(-support) model and physical health outcomes: A review of the strain and buffer hypotheses. Psychol. Health 13, 909-936., van der Doef, M., Maes, S., 1999. The Job Demand-Control(-Support) model and psychological well-being: A review of 20 years of empirical research. Work Stress 13, 87-114]. Manipulation checks revealed that objective control altered perceptions of control but not perceptions of demand. It is suggested that beneficial effects of work-related control are unlikely to occur in the absence of reductions in perceived demand. Thus, contrary to the propositions of Karasek and colleagues, demand and control do not appear to be independent factors.

  7. The clinical endocrinology workforce: current status and future projections of supply and demand.

    Science.gov (United States)

    Vigersky, Robert A; Fish, Lisa; Hogan, Paul; Stewart, Andrew; Kutler, Stephanie; Ladenson, Paul W; McDermott, Michael; Hupart, Kenneth H

    2014-09-01

    Many changes in health care delivery, health legislation, and the physician workforce that affect the supply and demand for endocrinology services have occurred since the first published workforce study of adult endocrinologists in 2003. The objective of the study was to assess the current adult endocrinology workforce data and provide the first analysis of the pediatric endocrinology workforce and to project the supply of and demand for endocrinologists through 2025. A workforce model was developed from an analysis of proprietary and publicly available databases, consultation with a technical expert panel, and the results of an online survey of board-certified endocrinologists. The Endocrine Society commissioned The Lewin Group to estimate current supply and to project gaps between supply and demand for endocrinologists. A technical expert panel of senior endocrinologists provided context, clinical information, and direction. The following were measured: 1) the current adult and pediatric endocrinology workforce and the supply of and demand for endocrinologists through 2025 and 2) the number of additional entrants into the endocrinology work pool that would be required to close the gap between supply and demand. Currently there is a shortage of approximately 1500 adult and 100 pediatric full-time equivalent endocrinologists. The gap for adult endocrinologists will expand to 2700 without an increase in the number of fellows trained. An increase in the prevalence of diabetes mellitus further expands the demand for adult endocrinologists. The gap can be closed in 5 and 10 years by increasing the number of fellowship positions by 14.4% and 5.5% per year, respectively. The gap between supply and demand for pediatric endocrinologists will close by 2016, and thereafter an excess supply over demand will develop at the current rate of new entrants into the work force. There are insufficient adult endocrinologists to satisfy current and future demand. A number of proactive

  8. Resolving conflicts in task demands during balance recovery: does holding an object inhibit compensatory grasping?

    Science.gov (United States)

    Bateni, Hamid; Zecevic, Aleksandra; McIlroy, William E; Maki, Brian E

    2004-07-01

    The ability to reach and "grasp" (grip or touch) structures for support in reaction to instability is an important element of the postural repertoire. It is unclear, however, how the central nervous system (CNS) resolves the potential conflict between holding an object and the need to release the held object and grasp alternative support, particularly if the held object is perceived to be relevant to the task of stabilizing the body, e.g. an assistive device. This study examined whether compensatory grasping is inhibited when holding an object, and whether the influence differs when holding an assistive device (cane) versus a task-irrelevant object (top handle portion of a cane). We also investigated the influence of preloading the assistive device, to determine whether conflicting demands for arm-muscle activation (requiring disengagement of ongoing agonist or antagonist activity) would influence the inhibition of compensatory grasping. Unpredictable forward and backward platform translations were used to evoke the balancing reactions in 16 healthy young adults. A handrail was mounted to the right and foot motion was constrained by barriers, with the intent that successful balance recovery would (in large-perturbation trials) require subjects to release the held object and contact the rail with the right hand. Results showed that grasping reactions were commonly used to recover equilibrium when the hand was free (rail contact in 71% of large-perturbation trials). However, holding either the cane or canetop had a potent modulating effect: although early biceps activation was almost never inhibited completely (significant activity within 200 ms in 98% of trials), the average activation amplitude was attenuated by 30-64% and the average frequency of handrail contact was reduced by a factor of two or more. This reduced use of the rail occurred even though the consequence often involved falling against a safety harness or barriers. Handrail contact occurred least

  9. Neural basis of superior performance of action videogame players in an attention-demanding task.

    Science.gov (United States)

    Mishra, Jyoti; Zinni, Marla; Bavelier, Daphne; Hillyard, Steven A

    2011-01-19

    Steady-state visual evoked potentials (SSVEPs) were recorded from action videogame players (VGPs) and from non-videogame players (NVGPs) during an attention-demanding task. Participants were presented with a multi-stimulus display consisting of rapid sequences of alphanumeric stimuli presented at rates of 8.6/12 Hz in the left/right peripheral visual fields, along with a central square at fixation flashing at 5.5 Hz and a letter sequence flashing at 15 Hz at an upper central location. Subjects were cued to attend to one of the peripheral or central stimulus sequences and detect occasional targets. Consistent with previous behavioral studies, VGPs detected targets with greater speed and accuracy than NVGPs. This behavioral advantage was associated with an increased suppression of SSVEP amplitudes to unattended peripheral sequences in VGPs relative to NVGPs, whereas the magnitude of the attended SSVEPs was equivalent in the two groups. Group differences were also observed in the event-related potentials to targets in the alphanumeric sequences, with the target-elicited P300 component being of larger amplitude in VGPS than NVGPs. These electrophysiological findings suggest that the superior target detection capabilities of the VGPs are attributable, at least in part, to enhanced suppression of distracting irrelevant information and more effective perceptual decision processes.

  10. Prefrontal cortex activation upon a demanding virtual hand-controlled task: a new frontier for neuroergonomics

    Directory of Open Access Journals (Sweden)

    Marika eCarrieri

    2016-02-01

    Full Text Available Functional near-infrared spectroscopy (fNIRS is a non-invasive vascular-based functional neuroimaging technology that can assess, simultaneously from multiple cortical areas, concentration changes in oxygenated-deoxygenated hemoglobin at the level of the cortical microcirculation blood vessels. fNIRS, with its high degree of ecological validity and its very limited requirement of physical constraints to subjects, could represent a valid tool for monitoring cortical responses in the research field of neuroergonomics. In virtual reality (VR real situations can be replicated with greater control than those obtainable in the real world. Therefore, VR is the ideal setting where studies about neuroergonomics applications can be performed. The aim of the present study was to investigate, by a 20-channel fNIRS system, the dorsolateral/ventrolateral prefrontal cortex (DLPFC/VLPFC in subjects while performing a demanding VR hand-controlled task (HCT. Considering the complexity of the HCT, its execution should require the attentional resources allocation and the integration of different executive functions. The HCT simulates the interaction with a real, remotely-driven, system operating in a critical environment. The hand movements were captured by a high spatial and temporal resolution 3D hand-sensing device, the LEAP motion controller, a gesture-based control interface that could be used in VR for tele-operated applications. Fifteen University students were asked to guide, with their right hand/forearm, a virtual ball (VB over a virtual route (VROU reproducing a 42-m narrow road including some critical points. The subjects tried to travel as long as possible without making VB fall. The distance traveled by the guided VB was 70.2±37.2 m. The less skilled subjects failed several times in guiding the VB over the VROU. Nevertheless, a bilateral VLPFC activation, in response to the HCT execution, was observed in all the subjects. No correlation was found

  11. Prefrontal Cortex Activation Upon a Demanding Virtual Hand-Controlled Task: A New Frontier for Neuroergonomics.

    Science.gov (United States)

    Carrieri, Marika; Petracca, Andrea; Lancia, Stefania; Basso Moro, Sara; Brigadoi, Sabrina; Spezialetti, Matteo; Ferrari, Marco; Placidi, Giuseppe; Quaresima, Valentina

    2016-01-01

    Functional near-infrared spectroscopy (fNIRS) is a non-invasive vascular-based functional neuroimaging technology that can assess, simultaneously from multiple cortical areas, concentration changes in oxygenated-deoxygenated hemoglobin at the level of the cortical microcirculation blood vessels. fNIRS, with its high degree of ecological validity and its very limited requirement of physical constraints to subjects, could represent a valid tool for monitoring cortical responses in the research field of neuroergonomics. In virtual reality (VR) real situations can be replicated with greater control than those obtainable in the real world. Therefore, VR is the ideal setting where studies about neuroergonomics applications can be performed. The aim of the present study was to investigate, by a 20-channel fNIRS system, the dorsolateral/ventrolateral prefrontal cortex (DLPFC/VLPFC) in subjects while performing a demanding VR hand-controlled task (HCT). Considering the complexity of the HCT, its execution should require the attentional resources allocation and the integration of different executive functions. The HCT simulates the interaction with a real, remotely-driven, system operating in a critical environment. The hand movements were captured by a high spatial and temporal resolution 3-dimensional (3D) hand-sensing device, the LEAP motion controller, a gesture-based control interface that could be used in VR for tele-operated applications. Fifteen University students were asked to guide, with their right hand/forearm, a virtual ball (VB) over a virtual route (VROU) reproducing a 42 m narrow road including some critical points. The subjects tried to travel as long as possible without making VB fall. The distance traveled by the guided VB was 70.2 ± 37.2 m. The less skilled subjects failed several times in guiding the VB over the VROU. Nevertheless, a bilateral VLPFC activation, in response to the HCT execution, was observed in all the subjects. No correlation was found

  12. Cardiac adaptivity to attention-demanding tasks in children with a pervasive developmental disorder not otherwise specified (PDD-NOS)

    NARCIS (Netherlands)

    Althaus, M; Aarnoudse, CC; Minderaa, RB; Mulder, Gysbertus; Mulder, Lambertus

    1999-01-01

    Background: Decreases in heart rate variability (HRV) have been repeatedly demonstrated to be an index of effort allocation to attention-demanding tasks. Children with autistic-type problems in social interaction and in adapting to unfamiliar situations (DSM-IV: PDD-NOS) have been shown to have

  13. Matching presentational tools' ontology to part-task demands to foster problem-solving in business economics

    NARCIS (Netherlands)

    Slof, Bert; Erkens, Gijsbert; Kirschner, Paul A.

    2011-01-01

    Slof, B., Erkens, G., & Kirschner, P. A. (2010, July). Matching representational tools’ ontology to part-task demands to foster problem-solving in business economics. In K. Gomez, L. Lyons, & J. Radinsky (Eds.), Learning in the Disciplines: Proceedings of the 9th International Conference of the

  14. Interference between a fast-paced spatial puzzle task and verbal memory demands.

    Science.gov (United States)

    Epling, Samantha L; Blakely, Megan J; Russell, Paul N; Helton, William S

    2017-06-01

    Research continues to provide evidence that people are poor multi-taskers. Cognitive resource theory is a common explanation for the inability to efficiently perform multiple tasks at the same time. This theory proposes that one's limited supply of cognitive resources can be utilized faster than it is replenished, which results in a performance decline, particularly when these limited resources must be allocated among multiple tasks. Researchers have proposed both domain-specific, for example, spatial versus verbal processing resources, and domain general cognitive resources. In the present research, we investigated whether a spatial puzzle task performed simultaneously with a verbal recall task would impair performance in either task or both tasks, compared to performance on the tasks individually. As hypothesized, a reduction in word recall was found when dual-tasking, though performance on the puzzle task did not significantly differ between the single- and dual-task conditions. This is consistent, in part, with both a general resource theory and a Multiple Resource Theory, but further work is required to better understand the cognitive processing system. The employment of the recall task in the dual-task paradigm with a variety of secondary tasks will help to continue mapping out the specificity (or lack thereof) of cognitive resources utilized in various mental and physical tasks.

  15. A FUNCTIONAL NEUROIMAGING INVESTIGATION OF THE ROLES OF STRUCTURAL COMPLEXITY AND TASK-DEMAND DURING AUDITORY SENTENCE PROCESSING

    Science.gov (United States)

    Love, Tracy; Haist, Frank; Nicol, Janet; Swinney, David

    2009-01-01

    Using functional magnetic resonance imaging (fMRI), this study directly examined an issue that bridges the potential language processing and multi-modal views of the role of Broca’s area: the effects of task-demands in language comprehension studies. We presented syntactically simple and complex sentences for auditory comprehension under three different (differentially complex) task-demand conditions: passive listening, probe verification, and theme judgment. Contrary to many language imaging findings, we found that both simple and complex syntactic structures activated left inferior frontal cortex (L-IFC). Critically, we found activation in these frontal regions increased together with increased task-demands. Specifically, tasks that required greater manipulation and comparison of linguistic material recruited L-IFC more strongly; independent of syntactic structure complexity. We argue that much of the presumed syntactic effects previously found in sentence imaging studies of L-IFC may, among other things, reflect the tasks employed in these studies and that L-IFC is a region underlying mnemonic and other integrative functions, on which much language processing may rely. PMID:16881268

  16. Task demands and the pressures of everyday life: associations between cardiovascular reactivity and work blood pressure and heart rate.

    Science.gov (United States)

    Steptoe, A; Cropley, M; Joekes, K

    2000-01-01

    Associations between cardiovascular stress reactivity and blood pressure and heart rate recorded in everyday life were hypothesized to depend on the stressfulness of the ambulatory monitoring period relative to standardized tasks and on activity levels at the time of measurement. One hundred two female and 60 male school teachers carried out high- and low-demand tasks under standardized conditions and ambulatory monitoring during the working day. Stress ratings during the day were close to those recorded during the low-demand task. Reactions to the low-demand task were significant predictors of ambulatory blood pressure and heart rate independent of baseline, age, gender, and body mass. Associations were more consistent for ambulatory recordings taken when participants were seated than when they were standing and when the ambulatory monitoring day was considered to be as stressful as usual or more stressful than usual, and not less stressful than usual. Laboratory-field associations of cardiovascular activity depend in part on the congruence of stressfulness and physical activity level in the 2 situations.

  17. Cognitive demand of human sensorimotor performance during an extended space mission: a dual-task study.

    Science.gov (United States)

    Bock, Otmar; Weigelt, Cornelia; Bloomberg, Jacob J

    2010-09-01

    Two previous single-case studies found that the dual-task costs of manual tracking plus memory search increased during a space mission, and concluded that sensorimotor deficits during spaceflight may be related to cognitive overload. Since dual-task costs were insensitive to the difficulty of memory search, the authors argued that the overload may reflect stress-related problems of multitasking, rather than a scarcity of specific cognitive resources. Here we expand the available database and compare different types of concurrent task. Three subjects were repeatedly tested before, during, and after an extended mission on the International Space Station (ISS). They performed an unstable tracking task and four reaction-time tasks, both separately and concurrently. Inflight data could only be obtained during later parts of the mission. The tracking error increased from pre- to in flight by a factor of about 2, both under single- and dual-task conditions. The dual-task costs with a reaction-time task requiring rhythm production was 2.4 times higher than with a reaction-time task requiring visuo-spatial transformations, and 8 times higher than with a regular choice reaction-time task. Long-term sensorimotor deficits during spaceflight may reflect not only stress, but also a scarcity of resources related to complex motor programming; possibly those resources are tied up by sensorimotor adaptation to the space environment.

  18. The impact of reward and punishment on skill learning depends on task demands.

    Science.gov (United States)

    Steel, Adam; Silson, Edward H; Stagg, Charlotte J; Baker, Chris I

    2016-10-27

    Reward and punishment motivate behavior, but it is unclear exactly how they impact skill performance and whether the effect varies across skills. The present study investigated the effect of reward and punishment in both a sequencing skill and a motor skill context. Participants trained on either a sequencing skill (serial reaction time task) or a motor skill (force-tracking task). Skill knowledge was tested immediately after training, and again 1 hour, 24-48 hours, and 30 days after training. We found a dissociation of the effects of reward and punishment on the tasks, primarily reflecting the impact of punishment. While punishment improved serial reaction time task performance, it impaired force-tracking task performance. In contrast to prior literature, neither reward nor punishment benefitted memory retention, arguing against the common assumption that reward ubiquitously benefits skill retention. Collectively, these results suggest that punishment impacts skilled behavior more than reward in a complex, task dependent fashion.

  19. Amygdala responses to unpleasant pictures are influenced by task demands and positive affect trait.

    Science.gov (United States)

    Sanchez, Tiago A; Mocaiber, Izabela; Erthal, Fatima S; Joffily, Mateus; Volchan, Eliane; Pereira, Mirtes G; de Araujo, Draulio B; Oliveira, Leticia

    2015-01-01

    The role of attention in emotional processing is still the subject of debate. Recent studies have found that high positive affect in approach motivation narrows attention. Furthermore, the positive affect trait has been suggested as an important component for determining human variability in threat reactivity. We employed functional magnetic resonance imaging to investigate whether different states of attention control would modulate amygdala responses to highly unpleasant pictures relative to neutral and whether this modulation would be influenced by the positive affect trait. Participants (n = 22, 12 male) were scanned while viewing neutral (people) or unpleasant pictures (mutilated bodies) flanked by two peripheral bars. They were instructed to (a) judge the picture content as unpleasant or neutral or (b) to judge the difference in orientation between the bars in an easy condition (0 or 90(∘) orientation difference) or (c) in a hard condition (0 or 6(∘) orientation difference). Whole brain analysis revealed a task main effect of brain areas related to the experimental manipulation of attentional control, including the amygdala, dorsolateral prefrontal cortex, and posterior parietal cortex. Region of interest analysis showed an inverse correlation (r = -0.51, p pictures. In conclusion, the current study suggests that positive affect modulates attention effect on unpleasant pictures, therefore attenuating emotional responses.

  20. Amygdala responses to unpleasant pictures are influenced by task demands and positive affect trait

    Directory of Open Access Journals (Sweden)

    Tiago Arruda Sanchez

    2015-03-01

    Full Text Available The role of attention in emotional processing is still the subject of debate. Recent studies have found that high positive affect in approach motivation narrows attention. Furthermore, the positive affect trait has been suggested as an important component for determining human variability in threat reactivity. We employed fMRI to investigate whether different states of attention control would modulate amygdala responses to highly unpleasant pictures relative to neutral and whether this modulation would be influenced by the positive affect trait. Participants (n=22, 12 male were scanned while viewing neutral (people or unpleasant pictures (mutilated bodies flanked by two peripheral bars. They were instructed to (a judge the picture content as unpleasant or neutral or (b to judge the difference in orientation between the bars in an easy condition (0º or 90º orientation difference or (c in a hard condition (0º or 6º orientation difference. Whole brain analysis revealed a task main effect of brain areas related to the experimental manipulation of attentional control, including the amygdala, dorsolateral prefrontal cortex and posterior parietal cortex. ROI analysis showed an inverse correlation (r = -0.51, p < 0.01 between left amygdala activation and positive affect level when participants viewed unpleasant stimuli and judged bar orientation in the easy condition. This result suggests that subjects with high positive affect exhibit lower amygdala reactivity to distracting unpleasant pictures. In conclusion, the current study suggests that positive affect modulates attention effect on unpleasant pictures, therefore attenuating emotional responses.

  1. The impact of social threat cues on a card sorting task with attentional-shifting demands.

    Science.gov (United States)

    Mohlman, Jan; DeVito, Alyssa

    2017-12-01

    The current study investigated social anxiety and attentional control using two versions of a task designed to tap intentional shifting of attention and set switching: the standard Wisconsin Card Sorting Test (WCST; Heaton, 1981) and a modified version that included emotionally salient pictorial stimuli, the Emotional Faces Card Sorting Test (EFCST). A Group (lower-, higher-SPS) by Condition (WCST, EFCST) by Sorting Rule (color, form, number) interaction was expected in which the higher-SPS EFCST group would have worse overall performance and make more perseverative errors than the other groups. No differences were predicted on nonperseverative errors, which are typically caused by brief attentional lapses. Participants were 80 undergraduate students who scored in the upper and lower quartile of the distribution on the Social Phobia Scale (SPS; Mattick & Clarke, 1998) were randomly assigned to complete either the WCST or EFCST. On the WCST, the higher-SPS group showed performance similar to that of the lower-SPS group. On the EFCST, the higher-SPS group evidenced more perseverative errors in the condition that depicted angry faces. Interpretations based on a non-clinical sample limit the generalisability of the conclusions. Reliability of this new measure has yet to be established. Successful completion of the WCST requires more than set-shifting processes. These results suggest that the higher-SPS group in the EFCST condition might have had trouble disengaging attention from threat-related cues, despite ongoing corrective feedback. Copyright © 2017. Published by Elsevier Ltd.

  2. Attentional Demands of Balance Under Dual Task Conditions in Young Adults

    Directory of Open Access Journals (Sweden)

    Monire Nobahar Ahari

    2012-10-01

    Full Text Available Objectives: The aim of this study was to identify the role of attentional process in postural control using choice reaction time task while changing the visual and proprioceptive cues under difficult balance task (standing on one-leg. Methods: This cross-sectional study was conducted by participating 20 young people (22.75±2.29. Each subject performed one-leg standing as balance task for each of the following 2 test conditions: free balance position (single task, and balancing while performing secondary cognitive task (choice reaction time task. Each test was carried out for each of the following 3 sensory conditions: on hard surface with open eyes, on hard surface with closed eyes and on foam surface with closed eyes. One way ANOVA was used for analysis. Results: Analyses of the task conditions didn’t show significant difference between single and dual task under two sensory conditions, in open and in closed eye on hard surface (P>0.05, but there was significant difference between single and dual tasks on soft foam with closed eyes [t(19=-2.391, P=0.027]. Discussion: Findings revealed that significant difference in balance performance of individuals under three different sensory conditions caused by reduction in base of support and this effect can be seen in dual task condition as well. Therefore it can be concluded that the nature of the primary task have the most influence on balance performance and this is not the effect of dual task condition.

  3. Students and recorded lectures: survey on current use and demands for higher education

    NARCIS (Netherlands)

    Gorissen, Pierre; Van Bruggen, Jan; Jochems, Wim

    2012-01-01

    Gorissen, P., Van Bruggen, J., & Jochems, W. M. G. (2012). Students and recorded lectures: survey on current use and demands for higher education. Research In Learning Technology, 20(3). doi:10.3402/rlt.v20i0.17299

  4. Current economic downturn and supply chain : The significance of demand and inventory smoothing

    NARCIS (Netherlands)

    Cannella, S.; Ashayeri, J.; Miranda, P.A.; Bruccoleri, M.

    2014-01-01

    The aim of this article is to analyse and quantify the effects of demand and inventory smoothing into supply-chain performance, facing the extreme volatility and impetuous alteration of the market produced by the current economic recession. To do so, we model a traditional serial three-stage supply

  5. Increased Task Demand during Spatial Memory Testing Recruits the Anterior Cingulate Cortex

    Science.gov (United States)

    Carr, Joshua K.; Fournier, Neil M.; Lehmann, Hugo

    2016-01-01

    We examined whether increasing retrieval difficulty in a spatial memory task would promote the recruitment of the anterior cingulate cortex (ACC) similar to what is typically observed during remote memory retrieval. Rats were trained on the hidden platform version of the Morris Water Task and tested three or 30 d later. Retrieval difficulty was…

  6. Distracted in a Demanding Task : A Classification Study with Artificial Neural Networks

    NARCIS (Netherlands)

    Huijser, Stefan; Taatgen, Niels; van Vugt, Marieke; Verheij, Bart; Wiering, Marco

    An important issue in cognitive science research is to know what your subjects are thinking about. In this paper, we trained multiple artificial Neural Network (ANN) classifiers to predict whether subjects’ thoughts were focused on the task (i.e., on-task) or if they were distracted (i.e.,

  7. Adaptive strategy changes as a function of task demands : a study of car drivers

    NARCIS (Netherlands)

    Cnossen, Fokie; Meijman, Theo; Rothengatter, Talib

    2004-01-01

    When drivers perform additional tasks while driving, research shows conflicting results: primary driving performance may deteriorate but adaptive changes such as reducing driving speed have also been noted. We hypothesized that the nature of the secondary task may be important: drivers may give more

  8. Terminology of economics in Albanian: Current state, problems and tasks

    OpenAIRE

    Mulaj, Isa

    2012-01-01

    The primary aim of this paper was to analyze the state of terminology of economics in Albanian language, and depending on the problems identified, to address some recommendations as tasks that are deemed necessary for future research that would contribute to its standardization. The paper begun from the hypothesis that the terminology in question is relatively rich, but finds that academic and scientific research are very limited or largely neglected, thus creating a vacuum in its broader and...

  9. Supply and demand analysis of the current and future US neurology workforce.

    Science.gov (United States)

    Dall, Timothy M; Storm, Michael V; Chakrabarti, Ritashree; Drogan, Oksana; Keran, Christopher M; Donofrio, Peter D; Henderson, Victor W; Kaminski, Henry J; Stevens, James C; Vidic, Thomas R

    2013-07-30

    This study estimates current and projects future neurologist supply and demand under alternative scenarios nationally and by state from 2012 through 2025. A microsimulation supply model simulates likely career choices of individual neurologists, taking into account the number of new neurologists trained each year and changing demographics of the neurology workforce. A microsimulation demand model simulates utilization of neurology services for each individual in a representative sample of the population in each state and for the United States as a whole. Demand projections reflect increased prevalence of neurologic conditions associated with population growth and aging, and expanded coverage under health care reform. The estimated active supply of 16,366 neurologists in 2012 is projected to increase to 18,060 by 2025. Long wait times for patients to see a neurologist, difficulty hiring new neurologists, and large numbers of neurologists who do not accept new Medicaid patients are consistent with a current national shortfall of neurologists. Demand for neurologists is projected to increase from ∼18,180 in 2012 (11% shortfall) to 21,440 by 2025 (19% shortfall). This includes an increased demand of 520 full-time equivalent neurologists starting in 2014 from expanded medical insurance coverage associated with the Patient Protection and Affordable Care Act. In the absence of efforts to increase the number of neurology professionals and retain the existing workforce, current national and geographic shortfalls of neurologists are likely to worsen, exacerbating long wait times and reducing access to care for Medicaid beneficiaries. Current geographic differences in adequacy of supply likely will persist into the future.

  10. Eldercare Demands, Mental Health, and Work Performance : The Moderating Role of Satisfaction With Eldercare Tasks

    NARCIS (Netherlands)

    Zacher, Hannes; Jimmieson, Nerina L.; Winter, Gabriele

    Due to demographic changes, a growing number of employees provide in-home care to an elderly family member. Previous research suggested a negative relationship between employees' eldercare demands and their work performance. However, the empirical nature of this relationship and its boundary

  11. Reduced modulation of scanpaths in response to task demands in posterior cortical atrophy.

    Science.gov (United States)

    Shakespeare, Timothy J; Pertzov, Yoni; Yong, Keir X X; Nicholas, Jennifer; Crutch, Sebastian J

    2015-02-01

    A difficulty in perceiving visual scenes is one of the most striking impairments experienced by patients with the clinico-radiological syndrome posterior cortical atrophy (PCA). However whilst a number of studies have investigated perception of relatively simple experimental stimuli in these individuals, little is known about multiple object and complex scene perception and the role of eye movements in posterior cortical atrophy. We embrace the distinction between high-level (top-down) and low-level (bottom-up) influences upon scanning eye movements when looking at scenes. This distinction was inspired by Yarbus (1967), who demonstrated how the location of our fixations is affected by task instructions and not only the stimulus' low level properties. We therefore examined how scanning patterns are influenced by task instructions and low-level visual properties in 7 patients with posterior cortical atrophy, 8 patients with typical Alzheimer's disease, and 19 healthy age-matched controls. Each participant viewed 10 scenes under four task conditions (encoding, recognition, search and description) whilst eye movements were recorded. The results reveal significant differences between groups in the impact of test instructions upon scanpaths. Across tasks without a search component, posterior cortical atrophy patients were significantly less consistent than typical Alzheimer's disease patients and controls in where they were looking. By contrast, when comparing search and non-search tasks, it was controls who exhibited lowest between-task similarity ratings, suggesting they were better able than posterior cortical atrophy or typical Alzheimer's disease patients to respond appropriately to high-level needs by looking at task-relevant regions of a scene. Posterior cortical atrophy patients had a significant tendency to fixate upon more low-level salient parts of the scenes than controls irrespective of the viewing task. The study provides a detailed characterisation of

  12. Evolution and current status of demand response (DR) in electricity markets: Insights from PJM and NYISO

    International Nuclear Information System (INIS)

    Walawalkar, Rahul; Fernands, Stephen; Thakur, Netra; Chevva, Konda Reddy

    2010-01-01

    In electricity markets, traditional demand side management programs are slowly getting replaced with demand response (DR) programs. These programs have evolved since the early pilot programs launched in late 1990s. With the changes in market rules the opportunities have generally increased for DR for participating in emergency, economic and ancillary service programs. In recent times, various regulators have suggested that DR can also be used as a solution to meet supply - demand fluctuations in scenarios with significant penetration of variable renewable sources in grid. This paper provides an overview of the evolution of the DR programs in PJM and NYISO markets as well as analyzes current opportunities. Although DR participation has grown, most of the current participation is in the reliability programs, which are designed to provide load curtailment during peak days. This suggests that there is a significant gap between perception of ability of DR to mitigate variability of renewables and reality of current participation. DR in future can be scaled to play a more dynamic role in electricity markets, but that would require changes both on technology as well as policy front. Advances in building technologies and energy storage combined with appropriate price signals can lead to enhanced DR participation. (author)

  13. The Effect of Cerebellar Transcranial Direct Current Stimulation on A Throwing Task Depends on Individual Level of Task Performance.

    Science.gov (United States)

    Mizuguchi, Nobuaki; Katayama, Takashi; Kanosue, Kazuyuki

    2018-02-10

    The effect of cerebellar transcranial direct current stimulation (tDCS) on motor performance remains controversial. Some studies suggest that the effect of tDCS depends upon task-difficulty and individual level of task performance. Here, we investigated whether the effect of cerebellar tDCS on the motor performance depends upon the individual's level of performance. Twenty-four naïve participants practiced dart throwing while receiving a 2-mA cerebellar tDCS for 20 min under three stimulus conditions (anodal-, cathodal-, and sham-tDCS) on separate days with a double-blind, counter-balanced cross-over design. Task performance was assessed by measuring the distance between the center of the bull's eye and the dart's position. Although task performance tended to improve throughout the practice under all stimulus conditions, improvement within a given day was not significant as compared to the first no-stimulus block. In addition, improvement did not differ among stimulation conditions. However, the magnitude of improvement was associated with an individual's level of task performance only under cathodal tDCS condition (p performance improvement only for the sub-group of participants with lower performance levels as compared to that with sham-tDCS (p task performance. Thus, cerebellar tDCS would facilitate learning of a complex motor skill task only in a subset of individuals. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  14. Combined Task and Physical Demands Analyses towards a Comprehensive Human Work Model

    Science.gov (United States)

    2014-09-01

    new equipment or modifying tasks and providing training (van der Molen, Sluiter, Hulshof , Vink, & Frings-Dresen, 2005). List the Job Duties (the...00 1/SV, Defence Research and Development Canada. van der Molen, H. F., Sluiter, J. K., Hulshof , C. T. J. , Vink, P., & Frings-Dresen, M. H. W

  15. The neural dynamics of stimulus and response conflict processing as a function of response complexity and task demands

    Science.gov (United States)

    Donohue, Sarah E.; Appelbaum, Lawrence G.; McKay, Cameron C.; Woldorff, Marty G.

    2016-01-01

    Both stimulus and response conflict can disrupt behavior by slowing response times and decreasing accuracy. Although several neural activations have been associated with conflict processing, it is unclear how specific any of these are to the type of stimulus conflict or the amount of response conflict. Here, we recorded electrical brain activity, while manipulating the type of stimulus conflict in the task (spatial [Flanker] versus semantic [Stroop]) and the amount of response conflict (two versus four response choices). Behaviorally, responses were slower to incongruent versus congruent stimuli across all task and response types, along with overall slowing for higher response-mapping complexity. The earliest incongruency-related neural effect was a short-duration frontally-distributed negativity at ~200 ms that was only present in the Flanker spatial-conflict task. At longer latencies, the classic fronto-central incongruency-related negativity ‘Ninc’ was observed for all conditions, which was larger and ~100 ms longer in duration with more response options. Further, the onset of the motor-related lateralized readiness potential (LRP) was earlier for the two vs. four response sets, indicating that smaller response sets enabled faster motor-response preparation. The late positive complex (LPC) was present in all conditions except the two-response Stroop task, suggesting this late conflict-related activity is not specifically related to task type or response-mapping complexity. Importantly, across tasks and conditions, the LRP onset at or before the conflict-related Ninc, indicating that motor preparation is a rapid, automatic process that interacts with the conflict-detection processes after it has begun. Together, these data highlight how different conflict-related processes operate in parallel and depend on both the cognitive demands of the task and the number of response options. PMID:26827917

  16. Regional demand forecasting and simulation model: user's manual. Task 4, final report

    Energy Technology Data Exchange (ETDEWEB)

    Parhizgari, A M

    1978-09-25

    The Department of Energy's Regional Demand Forecasting Model (RDFOR) is an econometric and simulation system designed to estimate annual fuel-sector-region specific consumption of energy for the US. Its purposes are to (1) provide the demand side of the Project Independence Evaluation System (PIES), (2) enhance our empirical insights into the structure of US energy demand, and (3) assist policymakers in their decisions on and formulations of various energy policies and/or scenarios. This report provides a self-contained user's manual for interpreting, utilizing, and implementing RDFOR simulation software packages. Chapters I and II present the theoretical structure and the simulation of RDFOR, respectively. Chapter III describes several potential scenarios which are (or have been) utilized in the RDFOR simulations. Chapter IV presents an overview of the complete software package utilized in simulation. Chapter V provides the detailed explanation and documentation of this package. The last chapter describes step-by-step implementation of the simulation package using the two scenarios detailed in Chapter III. The RDFOR model contains 14 fuels: gasoline, electricity, natural gas, distillate and residual fuels, liquid gases, jet fuel, coal, oil, petroleum products, asphalt, petroleum coke, metallurgical coal, and total fuels, spread over residential, commercial, industrial, and transportation sectors.

  17. What limits dual-tasking in working memory? An investigation of the effect of sub-task demand on maintenance mechanisms employed during dual-tasking

    OpenAIRE

    Doherty, Jason Michael

    2016-01-01

    A number of models of working memory have been proposed since the seminal work of Baddeley and Hitch (1974) on the Multiple Component Model (MCM). Subsequent MCM research focussed on developing a theoretical framework based on modality-specific stores that can operate in parallel during dual-tasking. The MCM can be contrasted with theories of working memory that assume an attention-based domain-general shared resource responsible for both short term retention as well as on-line...

  18. Inhibitory and Working Memory Demands of the Day-Night Task in Children

    Science.gov (United States)

    Simpson, Andrew; Riggs, Kevin J.

    2005-01-01

    Gerstadt, Hong, and Diamond (1994) investigated the development of inhibitory control in children aged 3 1/2 - 7 years using the day-night task. In two studies we build on Gerstadt et al.'s findings with a measure of inhibitory control that can be used throughout childhood. In Study 1 (twenty-four 3 1/2-year-olds and sixteen 5-year-olds) we…

  19. Real-time changes in hippocampal energy demands during a spatial working memory task.

    Science.gov (United States)

    Kealy, John; Bennett, Rachel; Woods, Barbara; Lowry, John P

    2017-05-30

    Activity-dependent changes in hippocampal energy consumption have largely been determined using microdialysis. However, real-time recordings of brain energy consumption can be more accurately achieved using amperometric sensors, allowing for sensitive real-time monitoring of concentration changes. Here, we test the theory that systemic pre-treatment with glucose in rats prevents activity-dependent decreases in hippocampal glucose levels and thus enhances their performance in a spontaneous alternation task. Male Sprague Dawley rats were implanted into the hippocampus with either: 1) microdialysis probe; or 2) an oxygen sensor and glucose biosensor co-implanted together. Animals were pre-treated with either saline or glucose (250mg/kg) 30min prior to performing a single 20-min spontaneous alternation task in a +-maze. There were no significant differences found between either treatment group in terms of spontaneous alternation performance. Additionally, there was a significant difference found between treatment groups on hippocampal glucose levels measured using microdialysis (a decrease associated with glucose pre-treatment in control animals) but not amperometry. There were significant increases in hippocampal oxygen during +-maze exploration. Combining the findings from both methods, it appears that hippocampal activity in the spontaneous alternation task does not cause an increase in glucose consumption, despite an increase in regional cerebral blood flow (using oxygen supply as an index of blood flow) and, as such, pre-treatment with glucose does not enhance spontaneous alternation performance. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. A Work-Demand Analysis Compatible with Preemption-Aware Scheduling for Power-Aware Real-Time Tasks

    Directory of Open Access Journals (Sweden)

    Da-Ren Chen

    2013-01-01

    Full Text Available Due to the importance of slack time utilization for power-aware scheduling algorithms,we propose a work-demand analysis method called parareclamation algorithm (PRA to increase slack time utilization of the existing real-time DVS algorithms. PRA is an online scheduling for power-aware real-time tasks under rate-monotonic (RM policy. It can be implemented and fully compatible with preemption-aware or transition-aware scheduling algorithms without increasing their computational complexities. The key technique of the heuristics method doubles the analytical interval and turns the deferrable workload out the potential slack time. Theoretical proofs show that PRA guarantees the task deadlines in a feasible RM schedule and takes linear time and space complexities. Experimental results indicate that the proposed method combining the preemption-aware methods seamlessly reduces the energy consumption by 14% on average over their original algorithms.

  1. Effects of an attention demanding task on dynamic stability during treadmill walking

    Directory of Open Access Journals (Sweden)

    Troy Karen L

    2008-04-01

    Full Text Available Abstract Background People exhibit increased difficulty balancing when they perform secondary attention-distracting tasks while walking. However, a previous study by Grabiner and Troy (J. Neuroengineering Rehabil., 2005 found that young healthy subjects performing a concurrent Stroop task while walking on a motorized treadmill exhibited decreased step width variability. However, measures of variability do not directly quantify how a system responds to perturbations. This study re-analyzed data from Grabiner and Troy 2005 to determine if performing the concurrent Stroop task directly affected the dynamic stability of walking in these same subjects. Methods Thirteen healthy volunteers walked on a motorized treadmill at their self-selected constant speed for 10 minutes both while performing the Stroop test and during undisturbed walking. This Stroop test consisted of projecting images of the name of one color, printed in text of a different color, onto a wall and asking subjects to verbally identify the color of the text. Three-dimensional motions of a marker attached to the base of the neck (C5/T1 were recorded. Marker velocities were calculated over 3 equal intervals of 200 sec each in each direction. Mean variability was calculated for each time series as the average standard deviation across all strides. Both "local" and "orbital" dynamic stability were quantified for each time series using previously established methods. These measures directly quantify how quickly small perturbations grow or decay, either continuously in real time (local or discretely from one cycle to the next (orbital. Differences between Stroop and Control trials were evaluated using a 2-factor repeated measures ANOVA. Results Mean variability of trunk movements was significantly reduced during the Stroop tests compared to normal walking. Conversely, local and orbital stability results were mixed: some measures showed slight increases, while others showed slight decreases

  2. In a demanding task, three-handed manipulation is preferred to two-handed manipulation.

    Science.gov (United States)

    Abdi, Elahe; Burdet, Etienne; Bouri, Mohamed; Himidan, Sharifa; Bleuler, Hannes

    2016-02-25

    Equipped with a third hand under their direct control, surgeons may be able to perform certain surgical interventions alone; this would reduce the need for a human assistant and related coordination difficulties. However, does human performance improve with three hands compared to two hands? To evaluate this possibility, we carried out a behavioural study on the performance of naive adults catching objects with three virtual hands controlled by their two hands and right foot. The subjects could successfully control the virtual hands in a few trials. With this control strategy, the workspace of the hands was inversely correlated with the task velocity. The comparison of performance between the three and two hands control revealed no significant difference of success in catching falling objects and in average effort during the tasks. Subjects preferred the three handed control strategy, found it easier, with less physical and mental burden. Although the coordination of the foot with the natural hands increased trial after trial, about two minutes of practice was not sufficient to develop a sense of ownership towards the third arm.

  3. An electrophysiological study of task demands on concreteness effects: evidence for dual coding theory.

    Science.gov (United States)

    Welcome, Suzanne E; Paivio, Allan; McRae, Ken; Joanisse, Marc F

    2011-07-01

    We examined ERP responses during the generation of word associates or mental images in response to concrete and abstract concepts. Of interest were the predictions of dual coding theory (DCT), which proposes that processing lexical concepts depends on functionally independent but interconnected verbal and nonverbal systems. ERP responses were time-locked to either stimulus onset or response to compensate for potential latency differences across conditions. During word associate generation, but not mental imagery, concrete items elicited a greater N400 than abstract items. A concreteness effect emerged at a later time point during the mental imagery task. Data were also analyzed using time-frequency analysis that investigated synchronization of neuronal populations over time during processing. Concrete words elicited an enhanced late going desynchronization of theta-band power (723-938 ms post stimulus onset) during associate generation. During mental imagery, abstract items elicited greater delta-band power from 800 to 1,000 ms following stimulus onset, theta-band power from 350 to 205 ms before response, and alpha-band power from 900 to 800 ms before response. Overall, the findings support DCT in suggesting that lexical concepts are not amodal and that concreteness effects are modulated by tasks that focus participants on verbal versus nonverbal, imagery-based knowledge.

  4. Designing informative warning signals: Effects of indicator type, modality, and task demand on recognition speed and accuracy

    Science.gov (United States)

    Stevens, Catherine J.; Brennan, David; Petocz, Agnes; Howell, Clare

    2009-01-01

    An experiment investigated the assumption that natural indicators which exploit existing learned associations between a signal and an event make more effective warnings than previously unlearned symbolic indicators. Signal modality (visual, auditory) and task demand (low, high) were also manipulated. Warning effectiveness was indexed by accuracy and reaction time (RT) recorded during training and dual task test phases. Thirty-six participants were trained to recognize 4 natural and 4 symbolic indicators, either visual or auditory, paired with critical incidents from an aviation context. As hypothesized, accuracy was greater and RT was faster in response to natural indicators during the training phase. This pattern of responding was upheld in test phase conditions with respect to accuracy but observed in RT only in test phase conditions involving high demand and the auditory modality. Using the experiment as a specific example, we argue for the importance of considering the cognitive contribution of the user (viz., prior learned associations) in the warning design process. Drawing on semiotics and cognitive psychology, we highlight the indexical nature of so-called auditory icons or natural indicators and argue that the cogniser is an indispensable element in the tripartite nature of signification. PMID:20523852

  5. Current supply/demand outlook and its impact on gas marketing strategies

    International Nuclear Information System (INIS)

    Maffitt, D.

    1994-01-01

    The current supply/demand outlook for natural gas in Canada is discussed, starting with a review of natural gas supply trends since the deregulation of the market in 1985/86. Market demand trends and expansion of export pipeline capacity are summarized to demonstrate how radically the North American gas marketing industry has changed in the last decade. As of January 1st 1993, Canada ranked eleventh in the world with respect to remaining natural gas reserves (96 Tft 3 ), which represents only 2% of global gas reserves. Canada ranks third in gas production (5 Tft 3 /y), behind the USA and former Soviet Union (19 and 29 Tft 3 /y, respectively). In western Canada, gas production rates have increased 75% since deregulation. Canadian domestic demand has grown 24% since 1985 to the 1993 level of 2.1 Tft 3 /y, while exports to the USA have grown 144% to 2.2 Tft 3 /y. The present environment requires a 'just in time' attitude towards developing new gas reserves and arranging transportation and storage. Long term gas marketing transacations are increasingly deliverability-based, firm delivery commitments which include harsh penalties for nonperformance. 7 figs

  6. Chaotic home environment is associated with reduced infant processing speed under high task demands.

    Science.gov (United States)

    Tomalski, Przemysław; Marczuk, Karolina; Pisula, Ewa; Malinowska, Anna; Kawa, Rafał; Niedźwiecka, Alicja

    2017-08-01

    Early adversity has profound long-term consequences for child development across domains. The effects of early adversity on structural and functional brain development were shown for infants under 12 months of life. However, the causal mechanisms of these effects remain relatively unexplored. Using a visual habituation task we investigated whether chaotic home environment may affect processing speed in 5.5 month-old infants (n=71). We found detrimental effects of chaos on processing speed for complex but not for simple visual stimuli. No effects of socio-economic status on infant processing speed were found although the sample was predominantly middle class. Our results indicate that chaotic early environment may adversely affect processing speed in early infancy, but only when greater cognitive resources need to be deployed. The study highlights an attractive avenue for research on the mechanisms linking home environment with the development of attention control. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Basic emotion processing and the adolescent brain: Task demands, analytic approaches, and trajectories of changes

    Directory of Open Access Journals (Sweden)

    Larissa B. Del Piero

    2016-06-01

    Full Text Available Early neuroimaging studies suggested that adolescents show initial development in brain regions linked with emotional reactivity, but slower development in brain structures linked with emotion regulation. However, the increased sophistication of adolescent brain research has made this picture more complex. This review examines functional neuroimaging studies that test for differences in basic emotion processing (reactivity and regulation between adolescents and either children or adults. We delineated different emotional processing demands across the experimental paradigms in the reviewed studies to synthesize the diverse results. The methods for assessing change (i.e., analytical approach and cohort characteristics (e.g., age range were also explored as potential factors influencing study results. Few unifying dimensions were found to successfully distill the results of the reviewed studies. However, this review highlights the potential impact of subtle methodological and analytic differences between studies, need for standardized and theory-driven experimental paradigms, and necessity of analytic approaches that are can adequately test the trajectories of developmental change that have recently been proposed. Recommendations for future research highlight connectivity analyses and non-linear developmental trajectories, which appear to be promising approaches for measuring change across adolescence. Recommendations are made for evaluating gender and biological markers of development beyond chronological age.

  8. Academic Task Demand in the 21st-Century, High-Stakes-Accountability School: Mapping the Journey from Poor [To Fair to Good to Great] to Excellent?

    Science.gov (United States)

    Szczesiul, Stacy Agee; Nehring, James; Carey, Theodore

    2015-01-01

    Drawing on theoretical and empirical research concerning the relationship between academic work and student learning, this article explores the following questions: What skills are required to execute the academic tasks teachers assign on a daily basis? How do teachers and administrators interpret the task demands represented in instructional…

  9. Identifying interactive effects of task demands in lifting on estimates of in vivo low back joint loads.

    Science.gov (United States)

    Gooyers, Chad E; Beach, Tyson A C; Frost, David M; Howarth, Samuel J; Callaghan, Jack P

    2018-02-01

    This investigation examined interactions between the magnitude of external load, movement speed and (a)symmetry of load placement on estimates of in vivo joint loading in the lumbar spine during simulated occupational lifting. Thirty-two participants with manual materials handling experience were included in the study. Three-dimensional motion data, ground reaction forces, and activation of six bilateral trunk muscle groups were captured while participants performed lifts with two loads at two movement speeds and using two load locations. L4-L5 joint compression and shear force-time histories were estimated using an EMG-assisted musculoskeletal model of the lumbar spine. Results from this investigation provide strong evidence that known mechanical low back injury risk factors should not be viewed in isolation. Rather, injury prevention efforts need to consider the complex interactions that exist between external task demands and their combined influence on internal joint loading. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Current status and prospects for Kepco's steaming coal demand and supply

    International Nuclear Information System (INIS)

    Kim, E.W.

    1991-01-01

    Under the series of Korean Government 5 year economic development plans since 1962, energy consumption in Korea has increased at a rapid pace and industrialization in Korea has been accelerated. As far as coal imports are concerned, coking coal was first imported to Korea in the early 1970s for the first steelworks. Little interest was shown in steaming coal until the early 1970s owing to the cheaper imported oil. People became interested in steaming coal after the first oil crisis in 1973 and import began in 1980 for cement and other industrial uses. In general, electricity demand is increasing far more rapidly than energy consumption. The initial construction of two 560 megawatt power plants using bituminous coal began in 1978 and was completed in 1982. The maiden cargo of bituminous coal for power generation arrived in Korea that year and coal import has been increasing at a rapid rate since then to keep pace with increased consumption. As there are no indigenous bituminous coal resources in Korea and we must depend entirely on overseas coal for our needs to fuel power plants, stable securing of coal is very important. This paper explains the current status and prospects for KEPCOs (Korean Electric Power Corporation) coal demand and supply

  11. The Impact of the Current Economic Crisis on the Demand for Higher Education: An Analysis of Spanish Distance Education Universities

    Science.gov (United States)

    Reina-Paz, María Dolores; Rodríguez-Oromendía, Ainhoa; Sevilla-Sevilla, Claudia

    2012-01-01

    Spain is currently experiencing a difficult economic situation, and in recent years a significant change has been observed in the behavior of the demand for educational programs as a result of this situation. Recent studies reveal a change in student demand that does not have the same effect on all academic institutions. Bearing this behavior in…

  12. The Current Utilization and Future Demand of Radiopharmaceutical and Radioisotopes in Malaysia

    International Nuclear Information System (INIS)

    Ibrahim Ijang; Zakaria Ibrahim; Bohari Yaacob

    2013-01-01

    Radioisotope and pharmaceutical kits play an important role in nuclear medicine for non-invasive diagnosis and treatment of various cancers and cardiovascular disease. Our aim was to survey the current utilization and future demand of radiopharmaceuticals and radioisotopes in Malaysia. The survey methodology technique was done using questionnaire administration modes. The survey was done for four month duration from government hospitals that have nuclear medicine department. The most frequent pharmaceutical kits used in hospitals were Methylene Diphosphonic acid (MDP) for bone imaging and Diethylene Triamine Pantacetic acid (DTPA). Similarly radioisotopes widely used were Tc-99m and Iodine 131.Therefore if produced of Tc-99m by Nuclear Malaysia can improved in term of high quality products, Nuclear Malaysia could be the sole supplier of this product to hospitals in Malaysia. Similarly pharmaceutical kits especially MDP and DTPA, Nuclear Malaysia has the expertise and knowledge to supply these kits to the hospital. (author)

  13. Task-specific effect of transcranial direct current stimulation on motor learning

    Directory of Open Access Journals (Sweden)

    Cinthia Maria Saucedo Marquez

    2013-07-01

    Full Text Available Transcranial direct current stimulation (tDCS is a relatively new non-invasive brain stimulation technique that modulates neural processes. When applied to the human primary motor cortex (M1, tDCS has beneficial effects on motor skill learning and consolidation in healthy controls and in patients. However, it remains unclear whether tDCS improves motor learning in a general manner or whether these effects depend on which motor task is acquired. Here we compare whether the effect of tDCS differs when the same individual acquires (1 a Sequential Finger Tapping Task (SEQTAP and (2 a Visual Isometric Pinch Force Task (FORCE. Both tasks have been shown to be sensitive to tDCS applied over M1, however, the underlying processes mediating learning and memory formation might benefit differently from anodal-tDCS. Thirty healthy subjects were randomly assigned to an anodal-tDCS group or sham-group. Using a double-blind, sham-controlled cross-over design, tDCS was applied over M1 while subjects acquired each of the motor tasks over 3 consecutive days, with the order being randomized across subjects. We found that anodal-tDCS affected each task differently: The SEQTAP task benefited from anodal-tDCS during learning, whereas the FORCE task showed improvements only at retention. These findings suggest that anodal tDCS applied over M1 appears to have a task-dependent effect on learning and memory formation.

  14. Task demands modulate decision and eye movement responses in the chimeric face test: examining the right hemisphere processing account

    Directory of Open Access Journals (Sweden)

    Jason eCoronel

    2014-03-01

    Full Text Available A large and growing body of work, conducted in both brain-intact and brain-damaged populations, has used the free viewing chimeric face test as a measure of hemispheric dominance for the extraction of emotional information from faces. These studies generally show that normal right-handed individuals tend to perceive chimeric faces as more emotional if the emotional expression is presented on the half of the face to the viewer’s left (left hemiface. However, the mechanisms underlying this lateralized bias remain unclear. Here, we examine the extent to which this bias is driven by right hemisphere processing advantages versus default scanning biases in a unique way -- by changing task demands. In particular, we compare the original task with one in which right-hemisphere-biased processing cannot provide a decision advantage. Our behavioral and eye-movement data are inconsistent with the predictions of a default scanning bias account and support the idea that the left hemiface bias found in the chimeric face test is largely due to strategic use of right hemisphere processing mechanisms.

  15. JSC Advanced Curation: Research and Development for Current Collections and Future Sample Return Mission Demands

    Science.gov (United States)

    Fries, M. D.; Allen, C. C.; Calaway, M. J.; Evans, C. A.; Stansbery, E. K.

    2015-01-01

    Curation of NASA's astromaterials sample collections is a demanding and evolving activity that supports valuable science from NASA missions for generations, long after the samples are returned to Earth. For example, NASA continues to loan hundreds of Apollo program samples to investigators every year and those samples are often analyzed using instruments that did not exist at the time of the Apollo missions themselves. The samples are curated in a manner that minimizes overall contamination, enabling clean, new high-sensitivity measurements and new science results over 40 years after their return to Earth. As our exploration of the Solar System progresses, upcoming and future NASA sample return missions will return new samples with stringent contamination control, sample environmental control, and Planetary Protection requirements. Therefore, an essential element of a healthy astromaterials curation program is a research and development (R&D) effort that characterizes and employs new technologies to maintain current collections and enable new missions - an Advanced Curation effort. JSC's Astromaterials Acquisition & Curation Office is continually performing Advanced Curation research, identifying and defining knowledge gaps about research, development, and validation/verification topics that are critical to support current and future NASA astromaterials sample collections. The following are highlighted knowledge gaps and research opportunities.

  16. The application of subjective job task analysis techniques in physically demanding occupations: evidence for the presence of self-serving bias.

    Science.gov (United States)

    Lee-Bates, Benjamin; Billing, Daniel C; Caputi, Peter; Carstairs, Greg L; Linnane, Denise; Middleton, Kane

    2017-09-01

    The aim of this study was to determine if perceptions of physically demanding job tasks are biased by employee demographics and employment profile characteristics including: age, sex, experience, length of tenure, rank and if they completed or supervised a task. Surveys were administered to 427 Royal Australian Navy personnel who characterised 33 tasks in terms of physical effort, importance, frequency, duration and vertical/horizontal distance travelled. Results showed no evidence of bias resulting from participant characteristics, however participants who were actively involved in both task participation and supervision rated these tasks as more important than those involved only in the supervision of that task. This may indicate self-serving bias in which participants that are more actively involved in a task had an inflated perception of that task's importance. These results have important implications for the conduct of job task analyses, especially the use of subjective methodologies in the development of scientifically defensible physical employment standards. Practitioner Summary: To examine the presence of systematic bias in subjective job task analysis methodologies, a survey was conducted on a sample of Royal Australian Navy personnel. The relationship between job task descriptions and participant's demographic and job profile characteristics revealed the presence of self-serving bias affecting perceptions of task importance.

  17. Oak Ridge Isotope Products and Services - Current and Expected Supply and Demand

    International Nuclear Information System (INIS)

    Aaron, W.S.; Alexander, C.W.; Cline, R.L.; Collins, E.D.; Klein, J.A.; Knauer, J.B. Jr.; Mirzadeh, S.

    1999-01-01

    Oak Ridge National Laboratory (ORNL) has been a major center of isotope production research, development, and distribution for over 50 years. Currently, the major isotope production activities include (1) the production of transuranium element radioisotopes, including 252 Cf; (2) the production of medical and industrial radioisotopes; (3) maintenance and expansion of the capabilities for production of enriched stable isotopes; and, (4) preparation of a wide range of custom-order chemical and physical forms of isotope products, particularly in accelerator physics research. The recent supply of and demand for isotope products and services in these areas, research and development (R ampersand D), and the capabilities for future supply are described in more detail below. The keys to continuing the supply of these important products and services are the maintenance, improvement, and potential expansion of specialized facilities, including (1) the High Flux Isotope Reactor (HFIR), (2) the Radiochemical Engineering Development Center (REDC) and Radiochemical Development Laboratory (RDL) hot cell facilities, (3) the electromagnetic calutron mass separators and the plasma separation process equipment for isotope enrichment, and (4) the Isotope Research Materials Laboratory (IRML) equipment for preparation of specialized chemical and physical forms of isotope products. The status and plans for these ORNL isotope production facilities are also described below

  18. Mapping ecosystem services demand: A review of current research and future perspectives

    NARCIS (Netherlands)

    Wolff, S.; Schulp, C.J.E.; Verburg, P.H.

    2015-01-01

    Mapping the demand for ecosystem services (ES) has received increased attention in scientific research and is seen as a relevant tool to inform conservation planning, land use planning and management. Yet, there is a varying understanding of the concept of ES demand, which has implications on how

  19. Alternative methods for skin irritation testing: the current status : ECVAM skin irritation task force report 1

    NARCIS (Netherlands)

    Botham, P.A.; Earl, L.K.; Fentem, J.H.; Roguet, R.; Sandt, J.J.M.

    1998-01-01

    The ECVAM Skin Irritation Task Force was established in November 1996, primarily to prepare a report on the current status of the development and validation of alternative tests for skin irritation and corrosion and, in particular, to identify any appropriate non-animal tests for predicting human

  20. Modeling and managing urban water demand through smart meters: Benefits and challenges from current research and emerging trends

    Science.gov (United States)

    Cominola, A.; Giuliani, M.; Castelletti, A.; Piga, D.; Rizzoli, A. E.

    2015-12-01

    Urban population growth, climate and land use change are expected to boost residential water demand in urban contexts in the next decades. In such a context, developing suitable demand-side management strategies is essential to meet future water demands, pursue water savings, and reduce the costs for water utilities. Yet, the effectiveness of water demand management strategies (WDMS) relies on our understanding of water consumers' behavior, their consumption habits, and the water use drivers. While low spatial and temporal resolution water consumption data, as traditionally gathered for billing purposes, hardly support this understanding, the advent of high-resolution, smart metering technologies allowed for quasi real-time monitoring water consumption at the single household level. This, in turn, is advancing our ability in characterizing consumers' behavior, modeling, and designing user-oriented residential water demand management strategies. Several water smart metering programs have been rolled-out in the last two decades worldwide, addressing one or more of the following water demand management phases: (i) data gathering, (ii) water end-uses characterization, (iii) user modeling, (iv) design and implementation of personalized WDMS. Moreover, the number of research studies in this domain is quickly increasing and big economic investments are currently being devoted worldwide to smart metering programs. With this work, we contribute the first comprehensive review of more than 100 experiences in the field of residential water demand modeling and management, and we propose a general framework for their classification. We revise consolidated practices, identify emerging trends and highlight the challenges and opportunities for future developments given by the use of smart meters advancing residential water demand management. Our analysis of the status quo of smart urban water demand management research and market constitutes a structured collection of information

  1. Enhanced motor learning following task-concurrent dual transcranial direct current stimulation.

    Directory of Open Access Journals (Sweden)

    Sophia Karok

    Full Text Available OBJECTIVE: Transcranial direct current stimulation (tDCS of the primary motor cortex (M1 has beneficial effects on motor performance and motor learning in healthy subjects and is emerging as a promising tool for motor neurorehabilitation. Applying tDCS concurrently with a motor task has recently been found to be more effective than applying stimulation before the motor task. This study extends this finding to examine whether such task-concurrent stimulation further enhances motor learning on a dual M1 montage. METHOD: Twenty healthy, right-handed subjects received anodal tDCS to the right M1, dual tDCS (anodal current over right M1 and cathodal over left M1 and sham tDCS in a repeated-measures design. Stimulation was applied for 10 mins at 1.5 mA during an explicit motor learning task. Response times (RT and accuracy were measured at baseline, during, directly after and 15 mins after stimulation. Motor cortical excitability was recorded from both hemispheres before and after stimulation using single-pulse transcranial magnetic stimulation. RESULTS: Task-concurrent stimulation with a dual M1 montage significantly reduced RTs by 23% as early as with the onset of stimulation (p<0.01 with this effect increasing to 30% at the final measurement. Polarity-specific changes in cortical excitability were observed with MEPs significantly reduced by 12% in the left M1 and increased by 69% in the right M1. CONCLUSION: Performance improvement occurred earliest in the dual M1 condition with a stable and lasting effect. Unilateral anodal stimulation resulted only in trendwise improvement when compared to sham. Therefore, task-concurrent dual M1 stimulation is most suited for obtaining the desired neuromodulatory effects of tDCS in explicit motor learning.

  2. Motor unit recruitment for dynamic tasks: current understanding and future directions.

    Science.gov (United States)

    Hodson-Tole, Emma F; Wakeling, James M

    2009-01-01

    Skeletal muscle contains many muscle fibres that are functionally grouped into motor units. For any motor task there are many possible combinations of motor units that could be recruited and it has been proposed that a simple rule, the 'size principle', governs the selection of motor units recruited for different contractions. Motor units can be characterised by their different contractile, energetic and fatigue properties and it is important that the selection of motor units recruited for given movements allows units with the appropriate properties to be activated. Here we review what is currently understood about motor unit recruitment patterns, and assess how different recruitment patterns are more or less appropriate for different movement tasks. During natural movements the motor unit recruitment patterns vary (not always holding to the size principle) and it is proposed that motor unit recruitment is likely related to the mechanical function of the muscles. Many factors such as mechanics, sensory feedback, and central control influence recruitment patterns and consequently an integrative approach (rather than reductionist) is required to understand how recruitment is controlled during different movement tasks. Currently, the best way to achieve this is through in vivo studies that relate recruitment to mechanics and behaviour. Various methods for determining motor unit recruitment patterns are discussed, in particular the recent wavelet-analysis approaches that have allowed motor unit recruitment to be assessed during natural movements. Directions for future studies into motor recruitment within and between functional task groups and muscle compartments are suggested.

  3. Demand of the power industry of Russia for gas turbines: the current state and prospects

    Science.gov (United States)

    Filippov, S. P.; Dil'man, M. D.; Ionov, M. S.

    2017-11-01

    The use of gas-turbine plants (GTPs) in the power industry of Russia is analyzed. Attention is paid to microturbines and low-, medium-, high-, and superhigh-power GTPs. The efficiency of the gas-turbine plants of domestic and foreign manufacture is compared. The actual values of the installed capacity utilization factor and the corresponding efficiency values are calculated for most GTPs operating in the country. The long-term demand of the country's electric power industry for GTPs for the period until 2040 is determined. The estimates have been obtained for three basic applications of the gas turbines, viz., for replacement of the GTPs that have exhausted their lifetime, replacement of outdated gas-turbine plants at gas-and-oilburning power plants, and construction of new thermal power plants to cover the anticipated growing demand for electric power. According to the findings of the research, the main item in the structure of the demand for GTPs will be their use to replace the decommissioned steam-turbine plants, predominantly those integrated into combined-cycle plants. The priority of the reconstruction of the thermal power plants in operation over the construction of new ones is determined by the large excess of accumulated installed capacities in the country and considerable savings on capital costs using production sites with completed infrastructure. It is established that medium- and high-power GTPs will be the most in-demand plants in the electric power industry. The demand for low-power GTPs will increase at high rates. The demand for microturbines is expected to be rather great. The demand for superhigh-power plants will become quantitatively significant after 2025 and grow rapidly afterwards. The necessity of accelerated development of competitive domestic GTPs with a wide range of capacities and mastering of their series manufacture as well as production of licensed gas turbines at a high production localization level on the territory of the country

  4. Current status and future projections of LNG demand and supplies: A global prospective

    International Nuclear Information System (INIS)

    Kumar, Satish; Kwon, Hyouk-Tae; Choi, Kwang-Ho; Hyun Cho, Jae; Lim, Wonsub; Moon, Il

    2011-01-01

    An unceasing growth of gas consumption in domestic households, industry, and power plants has gradually turned natural gas into a major source of energy. Main drivers in this development are the technical and economic advantages of natural gas. It is a clean, versatile, and easily controllable fuel. On this basis, natural gas is often considered the form of energy that will be the 'bridging fuel' to a sustainable energy system, sometime after 2050. Unlike other main sources of energy, such as oil and coal, gas is not traded on an actual world market. This paper provides an overview on demand and supplies of natural gas (LNG) in the past as a function of gas prices, gas technology (gas sweetening, liquefaction, shipping and re-gasification), and gas market and how they have changed recently. It also discusses the likely developments in global LNG demand for the period to the year 2030. - Highlights: → This study provides an overview on demand and supplies of LNG in the past and future. → Outlook for LNG demand in Asia pacific region is very robust. → In past decade the shale gas production in USA has increased fivefold. → The future of European gas supply depends largely on the geopolitical environments. → Within the gas sector LNG is playing an ever increasing role in gas transportation.

  5. The Effects of 10 Hz Transcranial Alternating Current Stimulation on Audiovisual Task Switching

    Directory of Open Access Journals (Sweden)

    Michael S. Clayton

    2018-02-01

    Full Text Available Neural oscillations in the alpha band (7–13 Hz are commonly associated with disengagement of visual attention. However, recent studies have also associated alpha with processes of attentional control and stability. We addressed this issue in previous experiments by delivering transcranial alternating current stimulation at 10 Hz over posterior cortex during visual tasks (alpha tACS. As this stimulation can induce reliable increases in EEG alpha power, and given that performance on each of our visual tasks was negatively associated with alpha power, we assumed that alpha tACS would reliably impair visual performance. However, alpha tACS was instead found to prevent both deteriorations and improvements in visual performance that otherwise occurred during sham & 50 Hz tACS. Alpha tACS therefore appeared to exert a stabilizing effect on visual attention. This hypothesis was tested in the current, pre-registered experiment by delivering alpha tACS during a task that required rapid switching of attention between motion, color, and auditory subtasks. We assumed that, if alpha tACS stabilizes visual attention, this stimulation should make it harder for people to switch between visual tasks, but should have little influence on transitions between auditory and visual subtasks. However, in contrast to this prediction, we observed no evidence of impairments in visuovisual vs. audiovisual switching during alpha vs. control tACS. Instead, we observed a trend-level reduction in visuoauditory switching accuracy during alpha tACS. Post-hoc analyses showed no effects of alpha tACS in response time variability, diffusion model parameters, or on performance of repeat trials. EEG analyses also showed no effects of alpha tACS on endogenous or stimulus-evoked alpha power. We discuss possible explanations for these results, as well as their broader implications for current efforts to study the roles of neural oscillations in cognition using tACS.

  6. Is effect of transcranial direct current stimulation on visuomotor coordination dependent on task difficulty?

    Directory of Open Access Journals (Sweden)

    Yong Hyun Kwon

    2015-01-01

    Full Text Available Transcranial direct current stimulation (tDCS, an emerging technique for non-invasive brain stimulation, is increasingly used to induce changes in cortical excitability and modulate motor behavior, especially for upper limbs. The purpose of this study was to investigate the effects of tDCS of the primary motor cortex on visuomotor coordination based on three levels of task difficulty in healthy subjects. Thirty-eight healthy participants underwent real tDCS or sham tDCS. Using a single-blind, sham-controlled crossover design, tDCS was applied to the primary motor cortex. For real tDCS conditions, tDCS intensity was 1 mA while stimulation was applied for 15 minutes. For the sham tDCS, electrodes were placed in the same position, but the stimulator was turned off after 5 seconds. Visuomotor tracking task, consisting of three levels (levels 1, 2, 3 of difficulty with higher level indicating greater difficulty, was performed before and after tDCS application. At level 2, real tDCS of the primary motor cortex improved the accurate index compared to the sham tDCS. However, at levels 1 and 3, the accurate index was not significantly increased after real tDCS compared to the sham tDCS. These findings suggest that tasks of moderate difficulty may improve visuomotor coordination in healthy subjects when tDCS is applied compared with easier or more difficult tasks.

  7. Transcranial direct current stimulation over multiple days enhances motor performance of a grip task.

    Science.gov (United States)

    Fan, Julie; Voisin, Julien; Milot, Marie-Hélène; Higgins, Johanne; Boudrias, Marie-Hélène

    2017-09-01

    Recovery of handgrip is critical after stroke since it is positively related to upper limb function. To boost motor recovery, transcranial direct current stimulation (tDCS) is a promising, non-invasive brain stimulation technique for the rehabilitation of persons with stroke. When applied over the primary motor cortex (M1), tDCS has been shown to modulate neural processes involved in motor learning. However, no studies have looked at the impact of tDCS on the learning of a grip task in both stroke and healthy individuals. To assess the use of tDCS over multiple days to promote motor learning of a grip task using a learning paradigm involving a speed-accuracy tradeoff in healthy individuals. In a double-blinded experiment, 30 right-handed subjects (mean age: 22.1±3.3 years) participated in the study and were randomly assigned to an anodal (n=15) or sham (n=15) stimulation group. First, subjects performed the grip task with their dominant hand while following the pace of a metronome. Afterwards, subjects trained on the task, at their own pace, over 5 consecutive days while receiving sham or anodal tDCS over M1. After training, subjects performed de novo the metronome-assisted task. The change in performance between the pre and post metronome-assisted task was used to assess the impact of the grip task and tDCS on learning. Anodal tDCS over M1 had a significant effect on the speed-accuracy tradeoff function. The anodal tDCS group showed significantly greater improvement in performance (39.28±15.92%) than the sham tDCS group (24.06±16.35%) on the metronome-assisted task, t(28)=2.583, P=0.015 (effect size d=0.94). Anodal tDCS is effective in promoting grip motor learning in healthy individuals. Further studies are warranted to test its potential use for the rehabilitation of fine motor skills in stroke patients. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  8. The Attentional Demand of Automobile Driving Revisited: Occlusion Distance as a Function of Task-Relevant Event Density in Realistic Driving Scenarios.

    Science.gov (United States)

    Kujala, Tuomo; Mäkelä, Jakke; Kotilainen, Ilkka; Tokkonen, Timo

    2016-02-01

    We studied the utility of occlusion distance as a function of task-relevant event density in realistic traffic scenarios with self-controlled speed. The visual occlusion technique is an established method for assessing visual demands of driving. However, occlusion time is not a highly informative measure of environmental task-relevant event density in self-paced driving scenarios because it partials out the effects of changes in driving speed. Self-determined occlusion times and distances of 97 drivers with varying backgrounds were analyzed in driving scenarios simulating real Finnish suburban and highway traffic environments with self-determined vehicle speed. Occlusion distances varied systematically with the expected environmental demands of the manipulated driving scenarios whereas the distributions of occlusion times remained more static across the scenarios. Systematic individual differences in the preferred occlusion distances were observed. More experienced drivers achieved better lane-keeping accuracy than inexperienced drivers with similar occlusion distances; however, driving experience was unexpectedly not a major factor for the preferred occlusion distances. Occlusion distance seems to be an informative measure for assessing task-relevant event density in realistic traffic scenarios with self-controlled speed. Occlusion time measures the visual demand of driving as the task-relevant event rate in time intervals, whereas occlusion distance measures the experienced task-relevant event density in distance intervals. The findings can be utilized in context-aware distraction mitigation systems, human-automated vehicle interaction, road speed prediction and design, as well as in the testing of visual in-vehicle tasks for inappropriate in-vehicle glancing behaviors in any dynamic traffic scenario for which appropriate individual occlusion distances can be defined. © 2015, Human Factors and Ergonomics Society.

  9. Managing competing demands through task-switching and multitasking: a multi-setting observational study of 200 clinicians over 1000 hours.

    Science.gov (United States)

    Walter, Scott R; Li, Ling; Dunsmuir, William T M; Westbrook, Johanna I

    2014-03-01

    To provide a detailed characterisation of clinicians' work management strategies. 1002.3 h of observational data were derived from three previous studies conducted in a teaching hospital in Sydney, Australia, among emergency department (ED) doctors (n=40), ward doctors (n=57) and ward nurses (n=104). The rates of task-switching (pausing a task to handle an incoming task) and multitasking (adding a task in parallel to an existing task) were compared in each group. Random intercepts logistic regression was used to determine factors significantly associated with clinicians' use of task-switching over multitasking and to quantify variation between individual clinicians. Task-switching rates were higher among ED doctors (6.0 per hour) than ward staff (2.2 and 1.8 per hour for doctors and nurses, respectively) and vice versa for multitasking rates (9.2 vs 17.3 and 14.1 per hour). Clinicians' strategy use was significantly related to the nature and complexity of work and to the person they were working with. In some settings, time of day, day of the week or previous chosen strategy affected a clinician's strategy. Independent of these factors, there was significant variation between individual clinicians in their use of strategies in a given situation (ED doctors p=0.04, ward staff p=0.03). Despite differences in factors associated with work management strategy use among ED doctors, ward doctors and ward nurses, clinicians in all settings appeared to prioritise certain types of tasks over others. Documentation was generally given low priority in all groups, while the arrival of direct care tasks tended to be treated with high priority. These findings suggest that considerations of safety may be implicit in task-switching and multitasking decisions. Although these strategies have been cast in a negative light, future research should consider their role in optimising competing quality and efficiency demands.

  10. Transcranial direct current stimulation over the parietal cortex alters bias in item and source memory tasks.

    Science.gov (United States)

    Pergolizzi, Denise; Chua, Elizabeth F

    2016-10-01

    Neuroimaging data have shown that activity in the lateral posterior parietal cortex (PPC) correlates with item recognition and source recollection, but there is considerable debate about its specific contributions. Performance on both item and source memory tasks were compared between participants who were given bilateral transcranial direct current stimulation (tDCS) over the parietal cortex to those given prefrontal or sham tDCS. The parietal tDCS group, but not the prefrontal group, showed decreased false recognition, and less bias in item and source discrimination tasks compared to sham stimulation. These results are consistent with a causal role of the PPC in item and source memory retrieval, likely based on attentional and decision-making biases. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Key tasks in healthcare marketing: assessing importance and current level of knowledge.

    Science.gov (United States)

    Kennett, Pamela A; Henson, Steve W; Crow, Stephen M; Hartman, Sandra J

    2005-01-01

    When examining the healthcare industry, the need for continuing education in internal functions (i.e., HR management) has been documented. However, equally important to success in the healthcare industry are external functions such as marketing. In an expansion of research on internally focused functions, we report findings from an exploratory study designed to examine the perceptions of executives about managerial skill needs in the externally focused area of marketing. Specifically, we examine eight key tasks in marketing and ask executives to rate the level of knowledge required for each and then to assess current, or actual, levels of knowledge in the field. Findings suggest that pricing strategy, product strategy, and segmentation and targeting were the tasks that require the most knowledge for healthcare marketers, and that they do, in fact, perceive various gaps in all of the areas examined. Implications and suggestions for future research are provided.

  12. Considering supply and demand of electric energy in life cycle assessments - a review of current methodologies

    International Nuclear Information System (INIS)

    Rehberger, M.; Hiete, M.

    2015-01-01

    A stable power grid requires a balance between electricity supply and demand. To compensate for changes in the demand the network operator puts on or takes off power plants from the net. Peak load plants operate only at times of high electricity demand. As levels for air pollutants emissions are typically lower for peak load plants for reasons of cost-effectiveness, one could argue that a unit of electric energy consumed during peak load has always been associated with a higher environmental impact than at other times. Furthermore, renewable energy technologies, smart approaches for improving the matching between electricity consumption and supply and new products such as electric vehicles or net zero emission buildings gain in importance. In life cycle assessment (LCA) environmental impacts associated with the production and possibly transmission of electricity are most often assessed based on temporally averaged national electricity mixes as electricity flows cannot be traced back to their origin. Neither fluctuations in the supply structure nor the composition of energy supply at a certain moment or regional differences are accounted for. A literature review of approaches for handling electricity in LCA is carried out to compare strengths and weaknesses of the approaches. A better understanding and knowledge about the source of electricity at a given time and place might be valuable information for further reducing environmental impacts, e.g. by shifting electricity consumption to times with ample supply of renewables. Integrating such information into LCA will allow a fairer assessment of a variety of new products which accept a lower energy efficiency to achieve a better integration of renewables into the grid. (authors)

  13. Performance of an attention-demanding task during treadmill walking shifts the noise qualities of step-to-step variation in step width.

    Science.gov (United States)

    Grabiner, Mark D; Marone, Jane R; Wyatt, Marilynn; Sessoms, Pinata; Kaufman, Kenton R

    2018-06-01

    The fractal scaling evident in the step-to-step fluctuations of stepping-related time series reflects, to some degree, neuromotor noise. The primary purpose of this study was to determine the extent to which the fractal scaling of step width, step width and step width variability are affected by performance of an attention-demanding task. We hypothesized that the attention-demanding task would shift the structure of the step width time series toward white, uncorrelated noise. Subjects performed two 10-min treadmill walking trials, a control trial of undisturbed walking and a trial during which they performed a mental arithmetic/texting task. Motion capture data was converted to step width time series, the fractal scaling of which were determined from their power spectra. Fractal scaling decreased by 22% during the texting condition (p Step width and step width variability increased 19% and five percent, respectively (p step width fractal scaling. The change of the fractal scaling of step width is consistent with increased cognitive demand and suggests a transition in the characteristics of the signal noise. This may reflect an important advance toward the understanding of the manner in which neuromotor noise contributes to some types of falls. However, further investigation of the repeatability of the results, the sensitivity of the results to progressive increases in cognitive load imposed by attention-demanding tasks, and the extent to which the results can be generalized to the gait of older adults seems warranted. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Positive feedback : exploring current approaches in iterative travel demand model implementation.

    Science.gov (United States)

    2012-01-01

    Currently, the models that TxDOTs Transportation Planning and Programming Division (TPP) developed are : traditional three-step models (i.e., trip generation, trip distribution, and traffic assignment) that are sequentially : applied. A limitation...

  15. Effects of Panax ginseng, consumed with and without glucose, on blood glucose levels and cognitive performance during sustained 'mentally demanding' tasks.

    Science.gov (United States)

    Reay, Jonathon L; Kennedy, David O; Scholey, Andrew B

    2006-11-01

    Single doses of the traditional herbal treatment Panax ginseng have recently been shown to lower blood glucose levels and elicit cognitive improvements in healthy, overnight-fasted volunteers. The specific mechanisms responsible for these effects are not known. However, cognitive improvements may be related to the glycaemic properties of Panax ginseng. Using a double-blind, placebo-controlled, balanced-crossover design, 27 healthy young adults completed a 10 minute "cognitive demand" test battery at baseline. They then consumed capsules containing either ginseng (extract G115) or a placebo and 30 minutes later a drink containing glucose or placebo. A further 30 minutes later (i.e. 60 minutes post-baseline/capsules) they completed the "cognitive demand" battery six times in immediate succession. Depending on the condition to which the participant was allocated on that particular day, the combination of capsules/drink treatments corresponded to a dose of: 0mg G115/0 mg glucose (placebo); 200mg G115/0 mg glucose (ginseng); 0 mg G115/25 g glucose (glucose) or 200 mg G115/25 g glucose (ginseng/glucose combination). The 10 minute "cognitive demand" battery comprised a Serial Threes subtraction task (2 min); a Serial Sevens subtraction task (2 min); a Rapid Visual Information Processing task (5 min); and a "mental fatigue" visual analogue scale. Blood glucose levels were measured prior to the day's treatment, and before and after the post-dose completions of the battery. The results showed that both Panax ginseng and glucose enhanced performance of a mental arithmetic task and ameliorated the increase in subjective feelings of mental fatigue experienced by participants during the later stages of the sustained, cognitively demanding task performance. Accuracy of performing the Rapid Visual Information Processing task (RVIP) was also improved following the glucose load. There was no evidence of a synergistic relationship between Panax ginseng and exogenous glucose ingestion

  16. Changes in division of labour and tasks within public dentistry: relationship to employees work demands, health and work ability.

    Science.gov (United States)

    Rolander, Bo; Wåhlin, Charlotte; Johnston, Venerina; Wagman, Petra; Lindmark, Ulrika

    2016-08-01

    By 2023, fewer dentists are expected in Sweden, at the same time as the demand for dental care is expected to increase. Older people, in particular, are expected to require more dental health than previous generations. To meet this demand, the public sector dentistry in Sweden is moving towards changes in division of labour among dental professionals, including dentists, dental hygienists and dental nurses. However, the impact of this reallocation on the physical and psychosocial wellbeing of employees is unknown. The aim of this study was to compare workplaces with an equal or larger proportion of dental hygienists than dentists (HDH) with workplaces with a larger proportion of dentists than dental hygienists (HD) on the physical and psychosocial work load, musculoskeletal and psychosomatic disorders and sickness presence. A total of 298 persons employed in the Public Dental Service in a Swedish County Council participated in this study. The medium large clinics HDH reported 85% of employee's with considerably more high psychosocial demands compared to employees in medium HD (53%) and large HD (57%). Employees in medium large clinics HDH also reported sleep problems due to work (25%) compared with employees in medium large clinics HD (6%), large clinics HD (11%) and small clinics HDH (3%). Clinic size does not seem to influence the outcome of the HD and HD clinics to any great extent. Of all employees, about 94-100% reported high precision demands and 78-91% poor work postures.

  17. Opposite effects depending on learning and memory demands in dorsomedial prefrontal cortex lesioned rats performing an olfactory task.

    Science.gov (United States)

    Chaillan, F A; Marchetti, E; Delfosse, F; Roman, F S; Soumireu-Mourat, B

    1997-01-01

    In this study, the functional properties of the dorsomedial prefrontal cortex (dmPFC) of the rat were examined in two olfactory tasks. In a successive cue olfactory discrimination task, dmPFC lesioned animals improved performance across sessions more rapidly than operated control animals. In an olfactory task using fixed interval training, animals with similar lesions were impaired. Both effects, although opposite, can be explained by a temporal processing deficit. The present results seem to indicate that the dmPFC is required for timing, classified as part of non-declarative memory. As reference memory improved in the lesioned animals, the finding is that the dmPFC supports non-declarative memory and thus interacts with declarative memory in the long-term formation of the associations between a particular stimulus (olfactory cue) and particular responses.

  18. Tuition Elasticity of the Demand for Higher Education among Current Students: A Pricing Model.

    Science.gov (United States)

    Bryan, Glenn A.; Whipple, Thomas W.

    1995-01-01

    A pricing model is offered, based on retention of current students, that colleges can use to determine appropriate tuition. A computer-based model that quantifies the relationship between tuition elasticity and projected net return to the college was developed and applied to determine an appropriate tuition rate for a small, private liberal arts…

  19. Hunger and the Externalities of Dietary Preferences: Demand-Side Considerations of the Current Dietary Paradigm

    OpenAIRE

    Anastasia Pseiridis

    2012-01-01

    World hunger and the latest increases in global food prices are mainly dealt with by measures aimed at boosting supply and allowing markets to function more effectively. Motivated by the persistence of world hunger, we do not intend to contribute to either theory or empirical analysis in economics; we rather aim to show that current research and policies are locked in a sort of scientific paradigm which takes as given our dietary preferences, which are in fact fundamental in creating resource...

  20. Transfer-Appropriate Processing in Recognition Memory: Perceptual and Conceptual Effects on Recognition Memory Depend on Task Demands

    Science.gov (United States)

    Parks, Colleen M.

    2013-01-01

    Research examining the importance of surface-level information to familiarity in recognition memory tasks is mixed: Sometimes it affects recognition and sometimes it does not. One potential explanation of the inconsistent findings comes from the ideas of dual process theory of recognition and the transfer-appropriate processing framework, which…

  1. Changes in Elementary Mathematics Teachers' Understanding of Cognitive Demand: When Adapting, Creating, and Using Mathematical Performance Tasks

    Science.gov (United States)

    Jamieson, Thad Spencer

    2015-01-01

    The use of mathematics performance tasks can provide a window into how a student is applying mathematics to various situations, how they are reasoning mathematically and how they are applying conceptual knowledge through problem solving and critical thinking. The purpose of this study was to investigate, according to the elementary mathematics…

  2. How to fit demand side management (DSM) into current Chinese electricity system reform?

    International Nuclear Information System (INIS)

    Yu Yongzhen

    2012-01-01

    DSM is one of the best and most practical policy tools available to China for balancing environmental protection and economic growth. The new round of electricity system reform provides a good opportunity to consolidate and integrate DSM policy and expedite its development and implementation. DSM policy can be upgraded by incorporating it into the current electricity system reform. Comparing the potential acceleration of electricity price reform with the possibility of imposing a System Benefit Charge (SBC), the author argues that support for a SBC would be much easier to gather among policymakers and stakeholders in a short time and would have a much better policy effect in the current situation. The author discusses three kinds of price discrimination related to the DSM development in China: time-based electricity pricing, electricity price discrimination for industrial structure adjustment in China (Fujian Province as a case), and direct power purchases by large customers and preferential tariff policy. These can be well designed to be combined with DSM and energy efficiency policy. - Highlights: ► Elements of DSM have been in place since 1993, but without even and reinforced policy. ► DSM can be upgraded by fitting it into current Chinese electricity system reform. ► Both electricity price reform and SBC would mean increases in electricity payment. ►Imposing SBC is much easier and better than speeding up electricity price reform. ► Three kinds of price discrimination can be well designed to be combined with DSM.

  3. Electric Vehicles in Colorado: Anticipating Consumer Demand for Direct Current Fast Charging

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Eric W. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rames, Clement L. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-07-01

    To support the State of Colorado in planning for growth in direct current fast charging (DCFC) for electric vehicles, the National Renewable Energy Laboratory (NREL) has partnered with the Regional Air Quality Council (RAQC) and the Colorado Department of Transportation (CDOT) to analyze a number of DCFC investment scenarios. NREL analyzed existing electric vehicle registration data from IHS Markit (IHS) to highlight early trends in the electric vehicle market, which were compared with sales forecasts predicting large growth in the Colorado electric vehicle market. Electric vehicle forecasts were then used to develop future DCFC scenarios to be evaluated in a simulation environment to estimate consumer benefits of the hypothetical DCFC networks in terms of increased driving range and electric vehicle miles traveled (eVMT). Simulated utilization of the hypothetical DCFC networks was analyzed for geographic trends, particularly for correlations with vehicle electric range. Finally, a subset of simulations is presented for consumers with potentially inconsistent access to charging at their home location and presumably greater reliance on public DCFC infrastructure.

  4. The Influence of Task Demands, Verbal Ability and Executive Functions on Item and Source Memory in Autism Spectrum Disorder

    Science.gov (United States)

    Semino, Sara; Ring, Melanie; Bowler, Dermot M.; Gaigg, Sebastian B.

    2018-01-01

    Autism Spectrum Disorder (ASD) is generally associated with difficulties in contextual source memory but not single item memory. There are surprising inconsistencies in the literature, however, that the current study seeks to address by examining item and source memory in age and ability matched groups of 22 ASD and 21 comparison adults. Results…

  5. Monitoring transcranial direct current stimulation induced changes in cortical excitability during the serial reaction time task.

    Science.gov (United States)

    Ambrus, Géza Gergely; Chaieb, Leila; Stilling, Roman; Rothkegel, Holger; Antal, Andrea; Paulus, Walter

    2016-03-11

    The measurement of the motor evoked potential (MEP) amplitudes using single pulse transcranial magnetic stimulation (TMS) is a common method to observe changes in motor cortical excitability. The level of cortical excitability has been shown to change during motor learning. Conversely, motor learning can be improved by using anodal transcranial direct current stimulation (tDCS). In the present study, we aimed to monitor cortical excitability changes during an implicit motor learning paradigm, a version of the serial reaction time task (SRTT). Responses from the first dorsal interosseous (FDI) and forearm flexor (FLEX) muscles were recorded before, during and after the performance of the SRTT. Online measurements were combined with anodal, cathodal or sham tDCS for the duration of the SRTT. Negative correlations between the amplitude of online FDI MEPs and SRTT reaction times (RTs) were observed across the learning blocks in the cathodal condition (higher average MEP amplitudes associated with lower RTs) but no significant differences in the anodal and sham conditions. tDCS did not have an impact on SRTT performance, as would be predicted based on previous studies. The offline before-after SRTT MEP amplitudes showed an increase after anodal and a tendency to decrease after cathodal stimulation, but these changes were not significant. The combination of different interventions during tDCS might result in reduced efficacy of the stimulation that in future studies need further attention. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Current status of the tasks performed by the Nuclear Fuel Department for the CAREM project

    International Nuclear Information System (INIS)

    Kaufmann, Federico; Perez, Lidia E.; Perez, Aaldo; Marchi, Daniel E.

    2009-01-01

    CAREM Project required to the Nuclear Fuels Department to perform the necessary tasks to define the powder characteristics and natural UO 2 -Gd 2 O 3 , UO 2 -1.8 and 3.1 % enrichment fuel pellets manufacturing and control parameters. To start with these tasks it was necessary to hire and train staff, begin the licensing process of the facilities, update infrastructure works and equipment of existing facilities. A brief description of the tasks performed is shown. (author)

  7. Evaluating auditory perception and communication demands required to carry out work tasks and complimentary hearing resources and skills for older workers with hearing loss.

    Science.gov (United States)

    Jennings, M B; Shaw, L; Hodgins, H; Kuchar, D A; Bataghva, L Poost-Foroosh

    2010-01-01

    For older workers with acquired hearing loss, this loss as well as the changing nature of work and the workforce, may lead to difficulties and disadvantages in obtaining and maintaining employment. Currently there are very few instruments that can assist workplaces, employers and workers to prepare for older workers with hearing loss or with the evaluation of auditory perception demands of work, especially those relevant to communication, and safety sensitive workplaces that require high levels of communication. This paper introduces key theoretical considerations that informed the development of a new framework, The Audiologic Ergonomic (AE) Framework to guide audiologists, work rehabilitation professionals and workers in developing tools to support the identification and evaluation of auditory perception demands in the workplace, the challenges to communication and the subsequent productivity and safety in the performance of work duties by older workers with hearing loss. The theoretical concepts underpinning this framework are discussed along with next steps in developing tools such as the Canadian Hearing Demands Tool (C-HearD Tool) in advancing approaches to evaluate auditory perception and communication demands in the workplace.

  8. IEA Bioenergy Task 40Sustainable International Bioenergy Trade:Securing Supply and Demand Country Report 2014—United States

    Energy Technology Data Exchange (ETDEWEB)

    Hess, J. Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lamers, Patrick [Idaho National Lab. (INL), Idaho Falls, ID (United States); Roni, Mohammad S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jacobson, Jacob J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Heath, Brendi [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-01-01

    Logistical barrier are tied to feedstock harvesting, collection, storage and distribution. Current crop harvesting machinery is unable to selectively harvest preferred components of cellulosic biomass while maintaining acceptable levels of soil carbon and minimizing erosion. Actively managing biomass variability imposes additional functional requirements on biomass harvesting equipment. A physiological variation in biomass arises from differences in genetics, degree of crop maturity, geographical location, climatic events, and harvest methods. This variability presents significant cost and performance risks for bioenergy systems. Currently, processing standards and specifications for cellulosic feedstocks are not as well-developed as for mature commodities. Biomass that is stored with high moisture content or exposed to moisture during storage is susceptible to spoilage, rotting, spontaneous combustion, and odor problems. Appropriate storage methods and strategies are needed to better define storage requirements to preserve the volume and quality of harvested biomass over time and maintain its conversion yield. Raw herbaceous biomass is costly to collect, handle, and transport because of its low density and fibrous nature. Existing conventional, bale-based handling equipment and facilities cannot cost-effectively deliver and store high volumes of biomass, even with improved handling techniques. Current handling and transportation systems designed for moving woodchips can be inefficient for bioenergy processes due to the costs and challenges of transporting, storing, and drying high-moisture biomass. The infrastructure for feedstock logistics has not been defined for the potential variety of locations, climates, feedstocks, storage methods, processing alternatives, etc., which will occur at a national scale. When setting up biomass fuel supply chains, for large-scale biomass systems, logistics are a pivotal part in the system. Various studies have shown that long

  9. "Binary" and "non-binary" detection tasks: are current performance measures optimal?

    Science.gov (United States)

    Gur, David; Rockette, Howard E; Bandos, Andriy I

    2007-07-01

    We have observed that a very large fraction of responses for several detection tasks during the performance of observer studies are in the extreme ranges of lower than 11% or higher than 89% regardless of the actual presence or absence of the abnormality in question or its subjectively rated "subtleness." This observation raises questions regarding the validity and appropriateness of using multicategory rating scales for such detection tasks. Monte Carlo simulation of binary and multicategory ratings for these tasks demonstrate that the use of the former (binary) often results in a less biased and more precise summary index and hence may lead to a higher statistical power for determining differences between modalities.

  10. Effect of Postural Control Demands on Early Visual Evoked Potentials during a Subjective Visual Vertical Perception Task in Adolescents with Idiopathic Scoliosis.

    Science.gov (United States)

    Chang, Yi-Tzu; Meng, Ling-Fu; Chang, Chun-Ju; Lai, Po-Liang; Lung, Chi-Wen; Chern, Jen-Suh

    2017-01-01

    Subjective visual vertical (SVV) judgment and standing stability were separately investigated among patients with adolescent idiopathic scoliosis (AIS). Although, one study has investigated the central mechanism of stability control in the AIS population, the relationships between SVV, decreased standing stability, and AIS have never been investigated. Through event-related potentials (ERPs), the present study examined the effect of postural control demands (PDs) on AIS central mechanisms related to SVV judgment and standing stability to elucidate the time-serial stability control process. Thirteen AIS subjects (AIS group) and 13 age-matched adolescents (control group) aged 12-18 years were recruited. Each subject had to complete an SVV task (i.e., the modified rod-and-frame [mRAF] test) as a stimulus, with online electroencephalogram recording being performed in the following three standing postures: feet shoulder-width apart standing, feet together standing, and tandem standing. The behavioral performance in terms of postural stability (center of pressure excursion), SVV (accuracy and reaction time), and mRAF-locked ERPs (mean amplitude and peak latency of the P1, N1, and P2 components) was then compared between the AIS and control groups. In the behavioral domain, the results revealed that only the AIS group demonstrated a significantly accelerated SVV reaction time as the PDs increased. In the cerebral domain, significantly larger P2 mean amplitudes were observed during both feet shoulder-width-apart standing and feet together standing postures compared with during tandem standing. No group differences were noted in the cerebral domain. The results indicated that (1) during the dual-task paradigm, a differential behavioral strategy of accelerated SVV reaction time was observed in the AIS group only when the PDs increased and (2) the decrease in P2 mean amplitudes with the increase in the PD levels might be direct evidence of the competition for central

  11. Effect of Postural Control Demands on Early Visual Evoked Potentials during a Subjective Visual Vertical Perception Task in Adolescents with Idiopathic Scoliosis

    Directory of Open Access Journals (Sweden)

    Yi-Tzu Chang

    2017-06-01

    Full Text Available Subjective visual vertical (SVV judgment and standing stability were separately investigated among patients with adolescent idiopathic scoliosis (AIS. Although, one study has investigated the central mechanism of stability control in the AIS population, the relationships between SVV, decreased standing stability, and AIS have never been investigated. Through event-related potentials (ERPs, the present study examined the effect of postural control demands (PDs on AIS central mechanisms related to SVV judgment and standing stability to elucidate the time-serial stability control process. Thirteen AIS subjects (AIS group and 13 age-matched adolescents (control group aged 12–18 years were recruited. Each subject had to complete an SVV task (i.e., the modified rod-and-frame [mRAF] test as a stimulus, with online electroencephalogram recording being performed in the following three standing postures: feet shoulder-width apart standing, feet together standing, and tandem standing. The behavioral performance in terms of postural stability (center of pressure excursion, SVV (accuracy and reaction time, and mRAF-locked ERPs (mean amplitude and peak latency of the P1, N1, and P2 components was then compared between the AIS and control groups. In the behavioral domain, the results revealed that only the AIS group demonstrated a significantly accelerated SVV reaction time as the PDs increased. In the cerebral domain, significantly larger P2 mean amplitudes were observed during both feet shoulder-width-apart standing and feet together standing postures compared with during tandem standing. No group differences were noted in the cerebral domain. The results indicated that (1 during the dual-task paradigm, a differential behavioral strategy of accelerated SVV reaction time was observed in the AIS group only when the PDs increased and (2 the decrease in P2 mean amplitudes with the increase in the PD levels might be direct evidence of the competition for

  12. The SEDIBUD (Sediment Budgets in Cold Environments) Programme: Current activities and future key tasks

    Science.gov (United States)

    Beylich, A. A.; Lamoureux, S. F.; Decaulne, A.

    2012-04-01

    geomorphologists, hydrologists, ecologists, permafrost scientists and glaciologists. SEDIBUD has developed manuals and protocols (SEDIFLUX Manual, available online, see below) with a key set of primary surface process monitoring and research data requirements to incorporate results from these diverse projects and allow coordinated quantitative analysis across the programme. Defined SEDIBUD key test sites provide data on annual climate conditions, total discharge and particulate and dissolved fluxes as well as information on other relevant surface processes. A number of selected key test sites is providing high-resolution data on climate conditions, runoff and sedimentary fluxes, which in addition to the annual data contribute to the SEDIBUD metadata database which is currently developed. Comparable datasets from different SEDIBUD key test sites are integrated and analysed to address key research questions as defined in the SEDIBUD Objective (available online, see below). Defined SEDIBUD key tasks for the coming years include (i) The continued generation and compilation of comparable longer-term datasets on contemporary sedimentary fluxes and sediment yields from SEDIBUD key test sites worldwide, (ii) The continued extension of the SEDIBUD metadata database with these datasets, (iii) The testing of defined SEDIBUD hypotheses (available online, see below) by using the datasets continuously compiled in the SEDIBUD metadata database. Detailed information on the I.A.G./A.I.G. SEDIBUD Programme, SEDIBUD meetings, SEDIBUD publications and SEDIBUD online documents and databases is available at the SEDIBUD website under http://www.geomorph.org/wg/wgsb.html.

  13. Transcranial direct current stimulation (tDCS) to the supplementary motor area (SMA) influences performance on motor tasks.

    Science.gov (United States)

    Hupfeld, K E; Ketcham, C J; Schneider, H D

    2017-03-01

    The supplementary motor area (SMA) is believed to be highly involved in the planning and execution of both simple and complex motor tasks. This study aimed to examine the role of the SMA in planning the movements required to complete reaction time, balance, and pegboard tasks using anodal transcranial direct current stimulation (tDCS), which passes a weak electrical current between two electrodes, in order to modulate neuronal activity. Twenty healthy adults were counterbalanced to receive either tDCS (experimental condition) or no tDCS (control condition) for 3 days. During administration of tDCS, participants performed a balance task significantly faster than controls. After tDCS, subjects significantly improved their simple and choice reaction time. These results demonstrate that the SMA is highly involved in planning and executing fine and gross motor skill tasks and that tDCS is an effective modality for increasing SMA-related performance on these tasks. The findings may be generalizable and therefore indicate implications for future interventions using tDCS as a therapeutic tool.

  14. Cathodal Transcranial Direct Current Stimulation Over Left Dorsolateral Prefrontal Cortex Area Promotes Implicit Motor Learning in a Golf Putting Task.

    Science.gov (United States)

    Zhu, Frank F; Yeung, Andrew Y; Poolton, Jamie M; Lee, Tatia M C; Leung, Gilberto K K; Masters, Rich S W

    2015-01-01

    Implicit motor learning is characterized by low dependence on working memory and stable performance despite stress, fatigue, or multi-tasking. However, current paradigms for implicit motor learning are based on behavioral interventions that are often task-specific and limited when applied in practice. To investigate whether cathodal transcranial direct current stimulation (tDCS) over the left dorsolateral prefrontal cortex (DLPFC) area during motor learning suppressed working memory activity and reduced explicit verbal-analytical involvement in movement control, thereby promoting implicit motor learning. Twenty-seven healthy individuals practiced a golf putting task during a Training Phase while receiving either real cathodal tDCS stimulation over the left DLPFC area or sham stimulation. Their performance was assessed during a Test phase on another day. Verbal working memory capacity was assessed before and after the Training Phase, and before the Test Phase. Compared to sham stimulation, real stimulation suppressed verbal working memory activity after the Training Phase, but enhanced golf putting performance during the Training Phase and the Test Phase, especially when participants were required to multi-task. Cathodal tDCS over the left DLPFC may foster implicit motor learning and performance in complex real-life motor tasks that occur during sports, surgery or motor rehabilitation. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Current problems of the Bulgarian energy industry against the background of global short-term energy demand

    International Nuclear Information System (INIS)

    Batov, S.

    1999-01-01

    The energy demand during the next century due first of all to the expected growth of population necessitates more efficient technologies and huge investments. The production of nuclear energy requires higher safety as well as reduction of costs. A new form of partnership between the developed and developing countries is needed for transferring capital and technologies at special framework terms in order to avoid errors in the process of transition. The Energy Forum'99 highlights the current problems of Bulgarian energy branch and the projects for its future including better utilization of the existing energy resources, for development of new or renewable energy sources, not well utilized at present, and to harmonize the sector with better environmental protection. The most important problems discussed are: 1. Structure and restructuring strategy of the energy sector. Prices and tariffs. Privatization aspects. Construction of new replacement generating capacities; 2. Thermal power plants; 3. Nuclear power plants; 4. District heating and natural gas supply; 5. Efficient energy utilization; 6. Renewable energy sources; 7. Environmental protection and 8. Education

  16. Transcranial Direct Current Stimulation to Enhance Dual-Task Gait Training in Parkinson's Disease: A Pilot RCT.

    Science.gov (United States)

    Schabrun, Siobhan M; Lamont, Robyn M; Brauer, Sandra G

    2016-01-01

    To investigate the feasibility and safety of a combined anodal transcranial direct current stimulation (tDCS) and dual task gait training intervention in people with Parkinson's Disease (PD) and to provide data to support a sample size calculation for a fully powered trial should trends of effectiveness be present. A pilot, randomized, double-blind, sham-controlled parallel group trial with 12 week follow-up. A university physiotherapy department. Sixteen participants diagnosed with PD received nine dual task gait training sessions over 3 weeks. Participants were randomized to receive either active or sham tDCS applied for the first 20 minutes of each session. The primary outcome was gait speed while undertaking concurrent cognitive tasks (word lists, counting, conversation). Secondary measures included step length, cadence, Timed Up and Go, bradykinesia and motor speed. Gait speed, step length and cadence improved in both groups, under all dual task conditions. This effect was maintained at follow-up. There was no difference between the active and sham tDCS groups. Time taken to perform the TUGwords also improved, with no difference between groups. The active tDCS group did however increase their correct cognitive response rate during the TUGwords and TUGcount. Bradykinesia improved after training in both groups. Three weeks of dual task gait training resulted in improved gait under dual task conditions, and bradykinesia, immediately following training and at 12 weeks follow-up. The only parameter enhanced by tDCS was the number of correct responses while performing the dual task TUG. tDCS applied to M1 may not be an effective adjunct to dual task gait training in PD. Australia-New Zealand Clinical Trials Registry ACTRN12613001093774.

  17. Task force's viewpoint of the current BRH Program. Gonad shield, Part F

    International Nuclear Information System (INIS)

    Dolezal, A.

    1975-01-01

    A previous report on radiation protection during diagnostic exposure is reviewed. Some topics discussed are: Task Force regulations for the model by which routine use of patient shielding or gonad shielding would be required; shielding in relation to collimation, scatter radiation, and enforcement of regulations; and proposed regulations for reduction of unnecessary radiation

  18. Part-task training in the context of automation: current and future directions.

    Science.gov (United States)

    Gutzwiller, Robert S; Clegg, Benjamin A; Blitch, John G

    2013-01-01

    Automation often elicits a divide-and-conquer outlook. By definition, automation has been suggested to assume control over a part or whole task that was previously performed by a human (Parasuraman & Riley, 1997). When such notions of automation are taken as grounds for training, they readily invoke a part-task training (PTT) approach. This article outlines broad functions of automation as a source of PTT and reviews the PTT literature, focusing on the potential benefits and costs related to using automation as a mechanism for PTT. The article reviews some past work in this area and suggests a path to move beyond the type of work captured by the "automation as PTT" framework. An illustrative experiment shows how automation in training and PTT are actually separable issues. PTT with automation has some utility but ultimately remains an unsatisfactory framework for the future broad potential of automation during training, and we suggest that a new conceptualization is needed.

  19. Delegation of medical tasks in French radiation oncology departments: current situation and impact on residents' training.

    Science.gov (United States)

    Thureau, S; Challand, T; Bibault, J-E; Biau, J; Cervellera, M; Diaz, O; Faivre, J-C; Fumagalli, I; Leroy, T; Lescut, N; Martin, V; Pichon, B; Riou, O; Dubray, B; Giraud, P; Hennequin, C

    2013-10-01

    A national survey was conducted among the radiation oncology residents about their clinical activities and responsibilities. The aim was to evaluate the clinical workload and to assess how medical tasks are delegated and supervised. A first questionnaire was administered to radiation oncology residents during a national course. A second questionnaire was mailed to 59 heads of departments. The response rate was 62% for radiation oncology residents (99 questionnaires) and 51% for heads of department (30). Eighteen heads of department (64%) declared having written specifications describing the residents' clinical tasks and roles, while only 31 radiation oncology residents (34%) knew about such a document (P=0.009). A majority of residents were satisfied with the amount of medical tasks that were delegated to them. Older residents complained about insufficient exposure to new patient's consultation, treatment planning and portal images validation. The variations observed between departments may induce heterogeneous trainings and should be addressed specifically. National specifications are necessary to reduce heterogeneities in training, and to insure that the residents' training covers all the professional skills required to practice radiation oncology. A frame endorsed by academic and professional societies would also clarify the responsibilities of both residents and seniors. Copyright © 2013 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  20. Quantitative work demands, emotional demands, and cognitive stress symptoms in surgery nurses.

    Science.gov (United States)

    Elfering, Achim; Grebner, Simone; Leitner, Monika; Hirschmüller, Anja; Kubosch, Eva Johanna; Baur, Heiner

    2017-06-01

    In surgery, cognitive stress symptoms, including problems in concentrating, deciding, memorising, and reflecting are risks to patient safety. Recent evidence points to social stressors as antecedents of cognitive stress symptoms in surgery personnel. The current study tests whether cognitive stress symptoms are positively associated with emotional abuse, emotional- and task-related demands and resources in surgery work. Forty-eight surgery nurses from two hospitals filled out the Copenhagen Psychosocial Questionnaire in its German version. Task-related and emotional demands were positively related to cognitive stress symptoms. In a stepwise, multiple, linear regression of cognitive stress symptoms on task-related and emotional demands, emotional abuse and emotional demands were unique predictors (p emotional abuse, emotional demands, and, therefore, communication and cooperation team climate in surgery personnel.

  1. The long-term supply/demand trend of world energy and the current oil situation in the Asia

    International Nuclear Information System (INIS)

    Okamoto, Hiroyuki

    1996-01-01

    Total world primary energy consumption excluding the FSU increased by 2.9% in 1995, which is somewhat above the 10 year average rate of 2.4%. This reflected strong economic growth in most parts of the world. The increase in demand confirmed the recovery of the link between the economic growth and consumption of primary energy, which broke down in the period of oil crises. Oil demand in the Asian Emerging Market Economies has continued to be very strong. Oil demand has doubled in a decade in this region and is now one sixth of world consumption. Malaysia was the fastest growing oil market in the world in 1995 at 15.5%. In volume terms, S. Korea grew the most in the world by 170,000 b/d, closely followed by China and India. Because of the fast growing oil demand, many energy economists expect a tight supply situation in the Asian oil market in the early 21st Century. However, recent technological developments would be able to supply crude oil appropriate for an increase in oil demand. (author)

  2. Demand specifying variables and current ventilation rate requirements with respect to the future use of voc sensing for dcv control

    DEFF Research Database (Denmark)

    Kolarik, Jakub

    be also taken into account in the ventilation control. Recent development in gas sensing technology resulted in a new generation of relatively cheap and practically applicable sensors that can offer measurements of some of the pollutants mentioned above – mainly Volatile Organic Compounds (VOC......Demand Controlled Ventilation (DCV) is a well established principle to provide a certain indoor environmental quality, defined both in the terms of air quality and thermal comfort. This is accomplished by adjusting the supplied airflow rate according to a certain demand indicator, which......). This seems to bring a new dimension into the control of DCV systems. This paper is a contribution to the workshop on utilization of VOC sensing technology used for DCV control. The aim of the paper is to provide a short review of different types of demand variables used to control DCV systems and summarize...

  3. Transcranial direct current stimulation facilitates cognitive multi-task performance differentially depending on anode location and subtask.

    Directory of Open Access Journals (Sweden)

    Melissa eScheldrup

    2014-09-01

    Full Text Available There is a need to facilitate acquisition of real world cognitive multi-tasks that require long periods of training (e.g., air traffic control, intelligence analysis, medicine. Non-invasive brain stimulation – specifically transcranial Direct Current Stimulation (tDCS – has promise as a method to speed multi-task training. We hypothesized that during acquisition of the complex multi-task Space Fortress, subtasks that require focused attention on ship control would benefit from tDCS aimed at the dorsal attention network while subtasks that require redirection of attention would benefit from tDCS aimed at the right hemisphere ventral attention network. We compared effects of 30 min prefrontal and parietal stimulation to right and left hemispheres on subtask performance during the first 45 min of training. The strongest effects both overall and for ship flying (control and velocity subtasks were seen with a right parietal (C4 to left shoulder montage, shown by modeling to induce an electric field that includes nodes in both dorsal and ventral attention networks. This is consistent with the re-orienting hypothesis that the ventral attention network is activated along with the dorsal attention network if a new, task-relevant event occurs while visuospatial attention is focused (Corbetta et al., 2008. No effects were seen with anodes over sites that stimulated only dorsal (C3 or only ventral (F10 attention networks. The speed subtask (update memory for symbols benefited from an F9 anode over left prefrontal cortex. These results argue for development of tDCS as a training aid in real world settings where multi-tasking is critical.

  4. Transcranial direct current stimulation facilitates cognitive multi-task performance differentially depending on anode location and subtask.

    Science.gov (United States)

    Scheldrup, Melissa; Greenwood, Pamela M; McKendrick, Ryan; Strohl, Jon; Bikson, Marom; Alam, Mahtab; McKinley, R Andy; Parasuraman, Raja

    2014-01-01

    There is a need to facilitate acquisition of real world cognitive multi-tasks that require long periods of training (e.g., air traffic control, intelligence analysis, medicine). Non-invasive brain stimulation-specifically transcranial Direct Current Stimulation (tDCS)-has promise as a method to speed multi-task training. We hypothesized that during acquisition of the complex multi-task Space Fortress, subtasks that require focused attention on ship control would benefit from tDCS aimed at the dorsal attention network while subtasks that require redirection of attention would benefit from tDCS aimed at the right hemisphere ventral attention network. We compared effects of 30 min prefrontal and parietal stimulation to right and left hemispheres on subtask performance during the first 45 min of training. The strongest effects both overall and for ship flying (control and velocity subtasks) were seen with a right parietal (C4, reference to left shoulder) montage, shown by modeling to induce an electric field that includes nodes in both dorsal and ventral attention networks. This is consistent with the re-orienting hypothesis that the ventral attention network is activated along with the dorsal attention network if a new, task-relevant event occurs while visuospatial attention is focused (Corbetta et al., 2008). No effects were seen with anodes over sites that stimulated only dorsal (C3) or only ventral (F10) attention networks. The speed subtask (update memory for symbols) benefited from an F9 anode over left prefrontal cortex. These results argue for development of tDCS as a training aid in real world settings where multi-tasking is critical.

  5. Cryptography in the Cloud Computing: the Current State and Logical Tasks

    OpenAIRE

    Sergey Nikolaevich Kyazhin; Andrey Vladimirovich Moiseev

    2013-01-01

    The current state of the cloud computing (CC) information security is analysed and logical problems of storage and data transmission security at CC are allocated. Cryptographic methods of data security in CC, in particular, lightweight cryptography and the cryptography based on bilinear pairings are described.

  6. Cryptography in the Cloud Computing: the Current State and Logical Tasks

    Directory of Open Access Journals (Sweden)

    Sergey Nikolaevich Kyazhin

    2013-09-01

    Full Text Available The current state of the cloud computing (CC information security is analysed and logical problems of storage and data transmission security at CC are allocated. Cryptographic methods of data security in CC, in particular, lightweight cryptography and the cryptography based on bilinear pairings are described.

  7. Task-related modulation of visual neglect in cancellation tasks

    OpenAIRE

    Sarri, Margarita; Greenwood, Richard; Kalra, Lalit; Driver, Jon

    2008-01-01

    Unilateral neglect involves deficits of spatial exploration and awareness that do not always affect a fixed portion of extrapersonal space, but may vary with current stimulation and possibly with task demands. Here, we assessed any ‘top-down’, task-related influences on visual neglect, with novel experimental variants of the cancellation test. Many different versions of the cancellation test are used clinically, and can differ in the extent of neglect revealed, though the exact factors determ...

  8. Identifying and acting on potentially inappropriate care? Inadequacy of current hospital coding for this task.

    Science.gov (United States)

    Cooper, P David; Smart, David R

    2017-06-01

    Recent Australian attempts to facilitate disinvestment in healthcare, by identifying instances of 'inappropriate' care from large Government datasets, are subject to significant methodological flaws. Amongst other criticisms has been the fact that the Government datasets utilized for this purpose correlate poorly with datasets collected by relevant professional bodies. Government data derive from official hospital coding, collected retrospectively by clerical personnel, whilst professional body data derive from unit-specific databases, collected contemporaneously with care by clinical personnel. Assessment of accuracy of official hospital coding data for hyperbaric services in a tertiary referral hospital. All official hyperbaric-relevant coding data submitted to the relevant Australian Government agencies by the Royal Hobart Hospital, Tasmania, Australia for financial year 2010-2011 were reviewed and compared against actual hyperbaric unit activity as determined by reference to original source documents. Hospital coding data contained one or more errors in diagnoses and/or procedures in 70% of patients treated with hyperbaric oxygen that year. Multiple discrete error types were identified, including (but not limited to): missing patients; missing treatments; 'additional' treatments; 'additional' patients; incorrect procedure codes and incorrect diagnostic codes. Incidental observations of errors in surgical, anaesthetic and intensive care coding within this cohort suggest that the problems are not restricted to the specialty of hyperbaric medicine alone. Publications from other centres indicate that these problems are not unique to this institution or State. Current Government datasets are irretrievably compromised and not fit for purpose. Attempting to inform the healthcare policy debate by reference to these datasets is inappropriate. Urgent clinical engagement with hospital coding departments is warranted.

  9. Current and projected water demand and water availability estimates under climate change scenarios in the Weyib River basin in Bale mountainous area of Southeastern Ethiopia

    Science.gov (United States)

    Serur, Abdulkerim Bedewi; Sarma, Arup Kumar

    2017-07-01

    This study intended to estimate the spatial and temporal variation of current and projected water demand and water availability under climate change scenarios in Weyib River basin, Bale mountainous area of Southeastern Ethiopia. Future downscaled climate variables from three Earth System Models under the three RCP emission scenarios were inputted into ArcSWAT hydrological model to simulate different components of water resources of a basin whereas current and projected human and livestock population of the basin is considered to estimate the total annual water demand for various purposes. Results revealed that the current total annual water demand of the basin is found to be about 289 Mm3, and this has to increase by 83.47% after 15 years, 200.67% after 45 years, and 328.78% after 75 years by the 2020s, 2050s, and 2080s, respectively, from base period water demand mainly due to very rapid increasing population (40.81, 130.80, and 229.12% by the 2020s, 2050s, and 2080s, respectively) and climatic variability. The future average annual total water availability in the basin is observed to be increased by ranging from 15.04 to 21.61, 20.08 to 23.34, and 16.21 to 39.53% by the 2020s, 2050s, and 2080s time slice, respectively, from base period available water resources (2333.39 Mm3). The current water availability per capita per year of the basin is about 3112.23 m3 and tends to decline ranging from 11.78 to 17.49, 46.02 to 47.45, and 57.18 to 64.34% by the 2020s, 2050s, and 2080s, respectively, from base period per capita per year water availability. This indicated that there might be possibility to fall the basin under water stress condition in the long term.

  10. [Historical development and current demands on medical training, further and advanced training in hygiene and infection prevention].

    Science.gov (United States)

    Exner, M; Kramer, A

    2012-11-01

    New risks in nosocomial infections and the dramatic increase in antibiotic-resistant pathogens in healthcare facilities have pointed to the urgent need for a good education of students and practitioners in the basics of hospital hygiene and infection prevention. On the other hand in the last 10 years a large number of institutes of hygiene in universities were closed with remarkable consequences concerning the decreased education in modern hygiene and public health. A broad historical overview over the last 200 years of teaching hygiene and public health at German universities is given which was integrated into the education of medical students. Nowadays many universities do not teach modern hygiene and public health. The demand of re-establishing new institutes of hygiene by the German Medical Council is discussed. The curriculum for the formation of hospital hygienists is presented.

  11. Searching for strategies to reduce the mechanical demands of the sit-to-stand task with a muscle-actuated optimal control model

    NARCIS (Netherlands)

    Bobbert, M.F.; Kistemaker, D.A.; Vaz, M.A.; Ackermann, M

    2016-01-01

    Background The sit-to-stand task, which involves rising unassisted from sitting on a chair to standing, is important in daily life. Many people with muscle weakness, reduced range of motion or loading-related pain in a particular joint have difficulty performing the task. How should a person

  12. Transcranial alternating current stimulation (tACS increases risk taking behavior in the Balloon Analogue Risk Task

    Directory of Open Access Journals (Sweden)

    Tal eSela

    2012-02-01

    Full Text Available The process of evaluating risks and benefits involves a complex neural network that includes the dorsolateral prefrontal cortex (DLPFC. It has been proposed that in conflict and reward situations, theta-band (4–8 Hz oscillatory activity in the frontal cortex may reflect an electrophysiological mechanism for coordinating neural networks monitoring behavior, as well as facilitating task-specific adaptive changes. The goal of the present study was to investigate the hypothesis that theta-band oscillatory balance between right and left frontal and prefrontal regions, with a predominance role to the right hemisphere, is crucial for regulatory control during decision-making under risk. In order to explore this hypothesis, we used transcranial Alternating Current Stimulation (tACS, a novel technique that provides the opportunity to explore the functional role of neuronal oscillatory activities and to establish a causal link between specific oscillations and functional lateralization in risky decision-making situations. For this aim, healthy participants were randomly allocated to one of three stimulation groups (LH stimulation / RH stimulation / Sham stimulation, with active AC stimulation delivered in a frequency-dependent manner (at 6.5 Hz; 1mA peak to-peak. During the AC stimulation, participants performed the Balloon Analog Risk Task. This experiment revealed that participants receiving LH stimulation displayed riskier decision-making style compared to sham and RH stimulation groups. However, there was no difference in decision-making behaviors between sham and RH stimulation groups. The current study extends the notion that DLPFC activity is critical for adaptive decision-making in the context of risk-taking and emphasis the role of theta-band oscillatory activity during risky decision-making situations.

  13. Analysis of Current and Future Water Demands in the Upper Indus Basin under IPCC Climate and Socio-Economic Scenarios Using a Hydro-Economic WEAP Model

    Directory of Open Access Journals (Sweden)

    Ali Amin

    2018-04-01

    Full Text Available Pakistan is currently facing physical and economic water scarcity issues that are further complicated by the rapid increase in its population and by climate change. Many studies have focused on the physical water scarcity using hydrological modeling and the measurement of the impact of climate change on water resources in the Upper Indus Basin (UIB. However, few studies have concentrated on the importance of the economic water scarcity, that is, the water management issue under the looming impacts of climate change and the population explosion of Pakistan. The purpose of this study is to develop a management strategy which helps to achieve water security and sustainability in the Upper Indus Basin (UIB with the help of different socio-economic and climate change scenarios using WEAP (Water Evaluation and Planning modeling. The streamflow data of five sub-basins (Gilgit, Hunza, Shigar, Shyok, and Astore and the entire Upper Indus Basin (UIB were calibrated (2006–2010 and validated (2011–2014 in the WEAP model. The coefficient of determination and Nash Sutcliffe values for the calibration period ranged from 0.81–0.96. The coefficient of determination and the Nash Sutcliffe values for the validation period ranged from 0.85–0.94. After the development of the WEAP model, the analysis of the unmet water demand and percent coverage of the water demand for the period of 2006–2050 was computed. Different scenarios were generated for external driving factors (population growth, urbanization, and living standards and the impact of climate change to evaluate their effect on the current water supply system. The results indicated that the future unmet water demand is likely to reach 134 million cubic meters (mcm by the year 2050 and that the external driving factors are putting more pressure on the supply service. This study further explores the importance of proposed dams (likely to be built until 2025 by WAPDA (Water and Power Development

  14. Brain activations during bimodal dual tasks depend on the nature and combination of component tasks

    Directory of Open Access Journals (Sweden)

    Emma eSalo

    2015-02-01

    Full Text Available We used functional magnetic resonance imaging to investigate brain activations during nine different dual tasks in which the participants were required to simultaneously attend to concurrent streams of spoken syllables and written letters. They performed a phonological, spatial or simple (speaker-gender or font-shade discrimination task within each modality. We expected to find activations associated specifically with dual tasking especially in the frontal and parietal cortices. However, no brain areas showed systematic dual task enhancements common for all dual tasks. Further analysis revealed that dual tasks including component tasks that were according to Baddeley’s model modality atypical, that is, the auditory spatial task or the visual phonological task, were not associated with enhanced frontal activity. In contrast, for other dual tasks, activity specifically associated with dual tasking was found in the left or bilateral frontal cortices. Enhanced activation in parietal areas, however, appeared not to be specifically associated with dual tasking per se, but rather with intermodal attention switching. We also expected effects of dual tasking in left frontal supramodal phonological processing areas when both component tasks required phonological processing and in right parietal supramodal spatial processing areas when both tasks required spatial processing. However, no such effects were found during these dual tasks compared with their component tasks performed separately. Taken together, the current results indicate that activations during dual tasks depend in a complex manner on specific demands of component tasks.

  15. Current Market Demand for Core Competencies of Librarianship—A Text Mining Study of American Library Association’s Advertisements from 2009 through 2014

    Directory of Open Access Journals (Sweden)

    Qinghong Yang

    2016-02-01

    Full Text Available As librarianship evolves, it is important to examine the changes that have taken place in professional requirements. To provide an understanding of the current market demand for core competencies of librarianship, this article conducts a semi-automatic methodology to analyze job advertisements (ads posted on the American Library Association (ALA Joblist from 2009 through 2014. There is evidence that the ability to solve unexpected complex problems and to provide superior customer service gained increasing importance for librarians during those years. The authors contend that the findings in this report question the status quo of core competencies of librarianship in the US job market.

  16. Effects of transcranial direct current stimulation (tDCS) on multiscale complexity of dual-task postural control in older adults.

    Science.gov (United States)

    Zhou, Diange; Zhou, Junhong; Chen, Hu; Manor, Brad; Lin, Jianhao; Zhang, Jue

    2015-08-01

    Transcranial direct current stimulation (tDCS) targeting the prefrontal cortex reduces the size and speed of standing postural sway in younger adults, particularly when performing a cognitive dual task. Here, we hypothesized that tDCS would alter the complex dynamics of postural sway as quantified by multiscale entropy (MSE). Twenty healthy older adults completed two study visits. Center-of-pressure (COP) fluctuations were recorded during single-task (i.e., quiet standing) and dual-task (i.e., standing while performing serial subtractions) conditions, both before and after a 20-min session of real or sham tDCS. MSE was used to estimate COP complexity within each condition. The percentage change in complexity from single- to dual-task conditions (i.e., dual-task cost) was also calculated. Before tDCS, COP complexity was lower (p = 0.04) in the dual-task condition as compared to the single-task condition. Neither real nor sham tDCS altered complexity in the single-task condition. As compared to sham tDCS, real tDCS increased complexity in the dual-task condition (p = 0.02) and induced a trend toward improved serial subtraction performance (p = 0.09). Moreover, those subjects with lower dual-task COP complexity at baseline exhibited greater percentage increases in complexity following real tDCS (R = -0.39, p = 0.05). Real tDCS also reduced the dual-task cost to complexity (p = 0.02), while sham stimulation had no effect. A single session of tDCS targeting the prefrontal cortex increased standing postural sway complexity with concurrent non-postural cognitive task. This form of noninvasive brain stimulation may be a safe strategy to acutely improve postural control by enhancing the system's capacity to adapt to stressors.

  17. A Study of Job Demands and Curriculum Development in Agricultural Training Related to the Muskegon County Wastewater Management System. Final Report. Volume II. Task Analysis Results.

    Science.gov (United States)

    Fisher, Harold S.; And Others

    This is the second volume of a four-volume report of a research project designed to (1) identify job needs for agricultural occupations which will result from the Muskegon County Wastewater Management System and perform a task analysis on each occupation, (2) develop instructional modules and determine their place in either high school or 2-year…

  18. The risk-benefit task of research ethics committees: An evaluation of current approaches and the need to incorporate decision studies methods

    Directory of Open Access Journals (Sweden)

    Bernabe Rosemarie D L C

    2012-04-01

    Full Text Available Abstract Background Research ethics committees (RECs are tasked to assess the risks and the benefits of a trial. Currently, two procedure-level approaches are predominant, the Net Risk Test and the Component Analysis. Discussion By looking at decision studies, we see that both procedure-level approaches conflate the various risk-benefit tasks, i.e., risk-benefit assessment, risk-benefit evaluation, risk treatment, and decision making. This conflation makes the RECs’ risk-benefit task confusing, if not impossible. We further realize that RECs are not meant to do all the risk-benefit tasks; instead, RECs are meant to evaluate risks and benefits, appraise risk treatment suggestions, and make the final decision. Conclusion As such, research ethics would benefit from looking beyond the procedure-level approaches and allowing disciplines like decision studies to be involved in the discourse on RECs’ risk-benefit task.

  19. When Age and Culture Interact in an Easy and Yet Cognitively Demanding Task: Older Adults, But Not Younger Adults, Showed the Expected Cultural Differences

    OpenAIRE

    Na, Jinkyung; Huang, Chih-Mao; Park, Denise C.

    2017-01-01

    The interaction between age and culture can have various implications for cognition as age represents the effect of biological processes whereas culture represents the effect of sustaining experiences. Nevertheless, their interaction has rarely been examined. Thus, based on the fact that Asians are more intuitive in reasoning than Americans, we examined how this cultural difference might interact with age. Young and old participants from the US and Singapore performed a categorization task (l...

  20. Impairments of working memory in schizophrenia and bipolar disorder: the effect of history of psychotic symptoms and different aspects of cognitive task demands

    Directory of Open Access Journals (Sweden)

    Dorota eFrydecka

    2014-11-01

    Full Text Available Comparisons of cognitive impairments between schizophrenia (SZ and bipolar disorder (BPD have produced mixed results. We applied different working memory (WM measures (Digit Span Forward and Backward, Short-delay and Long-delay CPT-AX, N-back to patients with SZ (n=23, psychotic BPD (n=19 and non-psychotic BPD (n=24, as well as to healthy controls (HC (n=18 in order to compare the level of WM impairments across the groups. With respect to the less demanding WM measures (Digit Span Forward and Backward, Short-delay CPT-AX, there were no between-groups differences in cognitive performance; however, with respect to the more demanding WM measures (Long-delay CPT-AX, N-back, we observed that the groups with psychosis (SZ, psychotic BPD did not differ from one another, but performed poorer than the group without history of psychosis (non-psychotic BPD. The history of psychotic symptoms may influence cognitive performance with respect to WM delay and load effects as measured by Long-delay CPT-AX and N-back tests respectively. We observed a positive correlation of WM performance with antipsychotic treatment and negative correlation with depressive symptoms in BPD and with negative symptoms in SZ subgroup. Our study suggests that WM dysfunctions are more closely related to the history of psychosis than to the diagnostic categories of SZ and BPD described by psychiatric classification systems.

  1. Development of a “Current Energy Mix Scenario” and a “Electricity as Main Energy Source Scenario” for electricity demand up to 2100

    Directory of Open Access Journals (Sweden)

    Mário J. S. Brito

    2014-06-01

    Full Text Available In this work, we develop a model to forecast world electricity production up to 2100. We analyze historical data for electricity production, population and GDP per Capita for the period 1900–2008. We show that electricity production follows general trends. First, there is an electricity intensity target of 0.20-0.25 kWh per unit of GDP (US$2012 as economies mature, except in countries traditionally relying heavily on renewable electricity (hydroelectricity, for whom this target ranges between 0.50 to 0.80 kWh per unit GDP. Also, countries that belong to the same region tend to follow the evolution of electricity production and GDP/Capita of a regional “modelcountry”. Equations that describe the behavior of these model countries are used to forecast electricity production per capita up to 2100 under a low and a high scenario for the evolution of GDP per Capita. For electricity production two main scenarios were set: “Current Energy MixScenario” and “Electricity as Main Energy Source Scenario”, with two additional sub scenarios considering slightly different electric intensities. Forecasts up to 2100 yield a demand forelectricity production 3.5 to 5 times higher than the current production for the “Current EnergyMix Scenario” and about 9 to 14 times for the “Electricity as Main Energy Source Scenario”. Forecasts for the “Current Energy Mix Scenario” matched well with forecasts from IEA/EIA (International Energy Agency/ Energy Information Administration while the forecasts for the“Electricity as the Main Energy Source Scenario” are much higher than current predictions.

  2. Job task characteristics of Australian emergency services volunteers during search and rescue operations.

    Science.gov (United States)

    Silk, Aaron; Lenton, Gavin; Savage, Robbie; Aisbett, Brad

    2018-02-01

    Search and rescue operations are necessary in locating, assisting and recovering individuals lost or in distress. In Australia, land-based search and rescue roles require a range of physically demanding tasks undertaken in dynamic and challenging environments. The aim of the current research was to identify and characterise the physically demanding tasks inherent to search and rescue operation personnel within Australia. These aims were met through a subjective job task analysis approach. In total, 11 criterion tasks were identified by personnel. These tasks were the most physically demanding, frequently occurring and operationally important tasks to these specialist roles. Muscular strength was the dominant fitness component for 7 of the 11 tasks. In addition to the discrete criterion tasks, an operational scenario was established. With the tasks and operational scenario identified, objective task analysis procedures can be undertaken so that practitioners can implement evidence-based strategies, such as physical selection procedures and task-based physical training programs, commensurate with the physical demands of search and rescue job roles. Practitioner Summary: The identification of physically demanding tasks amongst specialist emergency service roles predicates health and safety strategies which can be incorporated into organisations. Knowledge of physical task parameters allows employers to mitigate injury risk through the implementation of strategies modelled on the precise physical demands of the role.

  3. International Energy Agency (IEA) Task 40 — Sustainable International Energy Trade: Securing Supply and Demand -- Country Report 2010 for the United States

    Energy Technology Data Exchange (ETDEWEB)

    J. Richard Hess; Jacob J. Jacobson; Richard Nelson; Carl Wolf

    2011-12-01

    This report updates the status of U.S. biomass resources currently and future potentials for domestic and export markets of residues, energy crops, and woody resources. Includes energy and fuel production and consumption statistics, driving policies, targets, and government investment in bioenergy industry development.

  4. International Energy Agency (IEA) Task 40 — Sustainable International Energy Trade: Securing Supply and Demand -- Country Report 2009 for the United States

    Energy Technology Data Exchange (ETDEWEB)

    J. Richard Hess; Jacob J. Jacobson; Richard Nelson; Carl Wolf

    2009-06-01

    This report outlines the status of U.S. biomass resources currently and future potentials for domestic and export markets of residues, energy crops, and woody resources. Includes energy and fuel production and consumption statistics, driving policies, targets, and government investment in bioenergy industry development.

  5. When Age and Culture Interact in an Easy and Yet Cognitively Demanding Task: Older Adults, But Not Younger Adults, Showed the Expected Cultural Differences.

    Science.gov (United States)

    Na, Jinkyung; Huang, Chih-Mao; Park, Denise C

    2017-01-01

    The interaction between age and culture can have various implications for cognition as age represents the effect of biological processes whereas culture represents the effect of sustaining experiences. Nevertheless, their interaction has rarely been examined. Thus, based on the fact that Asians are more intuitive in reasoning than Americans, we examined how this cultural difference might interact with age. Young and old participants from the US and Singapore performed a categorization task (living vs. non-living). To measure their reliance on intuition, we manipulated the typicality of targets (animate vs. inanimate). We showed that (1) RTs for inanimate organisms were slower than RTs for animate organisms (atypicality cost), (2) the cost was particularly large for older adults and (3) an age × culture interaction was observed such that cultural differences in the cost (Singaporeans > Americans) was found only among older participants. Further, we demonstrated that the age effect was associated with cognitive function and the culture effect among older adults was associated with cultural values. Finally, a moderated mediation analysis suggests that cognitive function and cultural values interact with each other in order to jointly influence one's cognition.

  6. When Age and Culture Interact in an Easy and Yet Cognitively Demanding Task: Older Adults, But Not Younger Adults, Showed the Expected Cultural Differences

    Science.gov (United States)

    Na, Jinkyung; Huang, Chih-Mao; Park, Denise C.

    2017-01-01

    The interaction between age and culture can have various implications for cognition as age represents the effect of biological processes whereas culture represents the effect of sustaining experiences. Nevertheless, their interaction has rarely been examined. Thus, based on the fact that Asians are more intuitive in reasoning than Americans, we examined how this cultural difference might interact with age. Young and old participants from the US and Singapore performed a categorization task (living vs. non-living). To measure their reliance on intuition, we manipulated the typicality of targets (animate vs. inanimate). We showed that (1) RTs for inanimate organisms were slower than RTs for animate organisms (atypicality cost), (2) the cost was particularly large for older adults and (3) an age × culture interaction was observed such that cultural differences in the cost (Singaporeans > Americans) was found only among older participants. Further, we demonstrated that the age effect was associated with cognitive function and the culture effect among older adults was associated with cultural values. Finally, a moderated mediation analysis suggests that cognitive function and cultural values interact with each other in order to jointly influence one’s cognition. PMID:28396649

  7. A single session of prefrontal cortex transcranial direct current stimulation does not modulate implicit task sequence learning and consolidation.

    Science.gov (United States)

    Savic, Branislav; Müri, René; Meier, Beat

    Transcranial direct current stimulation (tDCS) is assumed to affect cortical excitability and dependent on the specific stimulation conditions either to increase or decrease learning. The purpose of this study was to modulate implicit task sequence learning with tDCS. As cortico-striatal loops are critically involved in implicit task sequence learning, tDCS was applied above the dorsolateral prefrontal cortex (DLPFC). In Experiment 1, anodal, cathodal, or sham tDCS was applied before the start of the sequence learning task. In Experiment 2, stimulation was applied during the sequence learning task. Consolidation of learning was assessed after 24 h. The results of both experiments showed that implicit task sequence learning occurred consistently but it was not modulated by different tDCS conditions. Similarly, consolidation measured after a 24 h-interval including sleep was also not affected by stimulation. These results indicate that a single session of DLPFC tDCS is not sufficient to modulate implicit task sequence learning. This study adds to the accumulating evidence that tDCS may not be as effective as originally thought. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Demand Uncertainty

    DEFF Research Database (Denmark)

    Nguyen, Daniel Xuyen

    This paper presents a model of trade that explains why firms wait to export and why many exporters fail. Firms face uncertain demands that are only realized after the firm enters the destination. The model retools the timing of uncertainty resolution found in productivity heterogeneity models....... This retooling addresses several shortcomings. First, the imperfect correlation of demands reconciles the sales variation observed in and across destinations. Second, since demands for the firm's output are correlated across destinations, a firm can use previously realized demands to forecast unknown demands...... in untested destinations. The option to forecast demands causes firms to delay exporting in order to gather more information about foreign demand. Third, since uncertainty is resolved after entry, many firms enter a destination and then exit after learning that they cannot profit. This prediction reconciles...

  9. GRI baseline projection of U.S. energy supply and demand to 2010. An occasional publication of Gas Research Institute on topics of current interest. December 1989

    International Nuclear Information System (INIS)

    Holtberg, P.D.; Woods, T.J.; Lihn, M.L.; McCabe, N.C.

    1989-12-01

    The report summarizes the 1989 GRI Baseline Projection of U.S. Energy Supply and Demand, which was adopted as a major input to the planning cycle leading to the development of GRI's 1991 R and D program. Summary tables, sectoral breakdowns of energy demand, and the natural gas supply and price trends are presented. Appendixes include a discussion of the methodology and assumptions used to prepare the 1989 projection, and analysis of the potential for higher levels of gas demand, a description of industrial and commercial cogeneration energy supply and demand, a comparison of the 1989 projection with previous GRI projections, and a discussion of additional data used in developing the projection

  10. Monitoring supports performance in a dual-task paradigm involving a risky decision-making task and a working memory task

    Directory of Open Access Journals (Sweden)

    Bettina eGathmann

    2015-02-01

    Full Text Available Performing two cognitively demanding tasks at the same time is known to decrease performance. The current study investigates the underlying executive functions of a dual-tasking situation involving the simultaneous performance of decision making under explicit risk and a working memory task. It is suggested that making a decision and performing a working memory task at the same time should particularly require monitoring - an executive control process supervising behavior and the state of processing on two tasks. To test the role of a supervisory/monitoring function in such a dual-tasking situation we investigated 122 participants with the Game of Dice Task plus 2-back task (GDT plus 2-back task. This dual task requires participants to make decisions under risk and to perform a 2-back working memory task at the same time. Furthermore, a task measuring a set of several executive functions gathered in the term concept formation (Modified Card Sorting Test, MCST and the newly developed Balanced Switching Task (BST, measuring monitoring in particular, were used. The results demonstrate that concept formation and monitoring are involved in the simultaneous performance of decision making under risk and a working memory task. In particular, the mediation analysis revealed that BST performance partially mediates the influence of MCST performance on the GDT plus 2-back task. These findings suggest that monitoring is one important subfunction for superior performance in a dual-tasking situation including decision making under risk and a working memory task.

  11. Monitoring supports performance in a dual-task paradigm involving a risky decision-making task and a working memory task

    Science.gov (United States)

    Gathmann, Bettina; Schiebener, Johannes; Wolf, Oliver T.; Brand, Matthias

    2015-01-01

    Performing two cognitively demanding tasks at the same time is known to decrease performance. The current study investigates the underlying executive functions of a dual-tasking situation involving the simultaneous performance of decision making under explicit risk and a working memory task. It is suggested that making a decision and performing a working memory task at the same time should particularly require monitoring—an executive control process supervising behavior and the state of processing on two tasks. To test the role of a supervisory/monitoring function in such a dual-tasking situation we investigated 122 participants with the Game of Dice Task plus 2-back task (GDT plus 2-back task). This dual task requires participants to make decisions under risk and to perform a 2-back working memory task at the same time. Furthermore, a task measuring a set of several executive functions gathered in the term concept formation (Modified Card Sorting Test, MCST) and the newly developed Balanced Switching Task (BST), measuring monitoring in particular, were used. The results demonstrate that concept formation and monitoring are involved in the simultaneous performance of decision making under risk and a working memory task. In particular, the mediation analysis revealed that BST performance partially mediates the influence of MCST performance on the GDT plus 2-back task. These findings suggest that monitoring is one important subfunction for superior performance in a dual-tasking situation including decision making under risk and a working memory task. PMID:25741308

  12. The current California drought through EDDI's eyes: early warning and monitoring of agricultural and hydrologic drought with the new Evaporative Demand Drought Index.

    Science.gov (United States)

    Hobbins, M.; McEvoy, D.; Huntington, J. L.; Wood, A. W.; Morton, C.; Verdin, J. P.

    2015-12-01

    We have developed a physically based, multi-scalar drought index—the Evaporative Demand Drought Index (EDDI)—to improve treatment of evaporative dynamics in drought monitoring. Existing popular drought indices—such as the Palmer Drought Severity Index that informs much of the US Drought Monitor (USDM)—have primarily relyied on precipitation and temperature (T) to represent hydroclimatic anomalies, leaving evaporative demand (E0) most often derived from poorly performing T-based parameterizations then used to derive actual evapotranspiration (ET) from LSMs. Instead, EDDI leverages the inter-relations of E0 and ET, measuring E0's physical response to surface drying anomalies due to two distinct land surface/atmosphere interactions: (i) in sustained drought, limited moisture availability forces E0 and ET into a complementary relation, whereby ET declines as E0 increases; and (ii) in "flash" droughts, E0 increases due to increasing advection or radiation. E0's rise in response to both drought types suggests EDDI's robustness as a monitor and leading indicator of drought. To drive EDDI, we use for E0 daily reference ET from the ASCE Standardized Reference ET equation forced by North American Land Data Assimilation System drivers. EDDI is derived by aggregating E0 anomalies from its long-term mean across a period of interest and normalizing them to a Z-score. Positive EDDI indicates drier than normal conditions (and so drought). We use the current historic California drought as a test-case in which to examine EDDI's performance in monitoring agricultural and hydrologic drought. We observe drought development and decompose the behavior of drought's evaporative drivers during in-drought intensification periods and wetting events. EDDI's performance as a drought leading indicator with respect to the USDM is tested in important agricultural regions. Comparing streamflow from several USGS gauges in the Sierra Nevada to EDDI, we find that EDDI tracks most major

  13. Improving access to emergency contraception pills through strengthening service delivery and demand generation: a systematic review of current evidence in low and middle-income countries.

    Directory of Open Access Journals (Sweden)

    Angela Dawson

    Full Text Available Emergency contraception pills (ECP are among the 13 essential commodities in the framework for action established by the UN Commission on Life-Saving Commodities for Women and Children. Despite having been on the market for nearly 20 years, a number of barriers still limit women's access to ECP in low- and middle-income countries (LMIC including limited consumer knowledge and poor availability. This paper reports the results of a review to synthesise the current evidence on service delivery strategies to improve access to ECP.A narrative synthesis methodology was used to examine peer reviewed research literature (2003 to 2013 from diverse methodological traditions to provide critical insights into strategies to improve access from a service delivery perspective. The studies were appraised using established scoring systems and the findings of included papers thematically analysed and patterns mapped across all findings using concept mapping.Ten papers were included in the review. Despite limited research of adequate quality, promising strategies to improve access were identified including: advance provision of ECP; task shifting and sharing; intersectoral collaboration for sexual assault; m-health for information provision; and scale up through national family planning programs.There are a number of gaps in the research concerning service delivery and ECP in LMIC. These include a lack of knowledge concerning private/commercial sector contributions to improving access, the needs of vulnerable groups of women, approaches to enhancing intersectoral collaboration, evidence for social marketing models and investment cases for ECP.

  14. Improving Access to Emergency Contraception Pills through Strengthening Service Delivery and Demand Generation: A Systematic Review of Current Evidence in Low and Middle-Income Countries

    Science.gov (United States)

    Dawson, Angela; Tran, Nguyen-Toan; Westley, Elizabeth; Mangiaterra, Viviana; Festin, Mario

    2014-01-01

    Objectives Emergency contraception pills (ECP) are among the 13 essential commodities in the framework for action established by the UN Commission on Life-Saving Commodities for Women and Children. Despite having been on the market for nearly 20 years, a number of barriers still limit women's access to ECP in low- and middle-income countries (LMIC) including limited consumer knowledge and poor availability. This paper reports the results of a review to synthesise the current evidence on service delivery strategies to improve access to ECP. Methods A narrative synthesis methodology was used to examine peer reviewed research literature (2003 to 2013) from diverse methodological traditions to provide critical insights into strategies to improve access from a service delivery perspective. The studies were appraised using established scoring systems and the findings of included papers thematically analysed and patterns mapped across all findings using concept mapping. Findings Ten papers were included in the review. Despite limited research of adequate quality, promising strategies to improve access were identified including: advance provision of ECP; task shifting and sharing; intersectoral collaboration for sexual assault; m-health for information provision; and scale up through national family planning programs. Conclusion There are a number of gaps in the research concerning service delivery and ECP in LMIC. These include a lack of knowledge concerning private/commercial sector contributions to improving access, the needs of vulnerable groups of women, approaches to enhancing intersectoral collaboration, evidence for social marketing models and investment cases for ECP. PMID:25285438

  15. Electricity demand in Kazakhstan

    International Nuclear Information System (INIS)

    Atakhanova, Zauresh; Howie, Peter

    2007-01-01

    Properties of electricity demand in transition economies have not been sufficiently well researched mostly due to data limitations. However, information on the properties of electricity demand is necessary for policy makers to evaluate effects of price changes on different consumers and obtain demand forecasts for capacity planning. This study estimates Kazakhstan's aggregate demand for electricity as well as electricity demand in the industrial, service, and residential sectors using regional data. Firstly, our results show that price elasticity of demand in all sectors is low. This fact suggests that there is considerable room for price increases necessary to finance generation and distribution system upgrading. Secondly, we find that income elasticity of demand in the aggregate and all sectoral models is less than unity. Of the three sectors, electricity demand in the residential sector has the lowest income elasticity. This result indicates that policy initiatives to secure affordability of electricity consumption to lower income residential consumers may be required. Finally, our forecast shows that electricity demand may grow at either 3% or 5% per year depending on rates of economic growth and government policy regarding price increases and promotion of efficiency. We find that planned supply increases would be sufficient to cover growing demand only if real electricity prices start to increase toward long-run cost-recovery levels and policy measures are implemented to maintain the current high growth of electricity efficiency

  16. Nutrient uplift in a cyclonic eddy increases diversity, primary productivity and iron demand of microbial communities relative to a western boundary current

    Directory of Open Access Journals (Sweden)

    Martina A. Doblin

    2016-04-01

    Full Text Available The intensification of western boundary currents in the global ocean will potentially influence meso-scale eddy generation, and redistribute microbes and their associated ecological and biogeochemical functions. To understand eddy-induced changes in microbial community composition as well as how they control growth, we targeted the East Australian Current (EAC region to sample microbes in a cyclonic (cold-core eddy (CCE and the adjacent EAC. Phototrophic and diazotrophic microbes were more diverse (2–10 times greater Shannon index in the CCE relative to the EAC, and the cell size distribution in the CCE was dominated (67% by larger micro-plankton $(\\geq 20\\lrm{\\mu }\\mathrm{m}$ ≥ 20 μ m , as opposed to pico- and nano-sized cells in the EAC. Nutrient addition experiments determined that nitrogen was the principal nutrient limiting growth in the EAC, while iron was a secondary limiting nutrient in the CCE. Among the diazotrophic community, heterotrophic NifH gene sequences dominated in the EAC and were attributable to members of the gamma-, beta-, and delta-proteobacteria, while the CCE contained both phototrophic and heterotrophic diazotrophs, including Trichodesmium, UCYN-A and gamma-proteobacteria. Daily sampling of incubation bottles following nutrient amendment captured a cascade of effects at the cellular, population and community level, indicating taxon-specific differences in the speed of response of microbes to nutrient supply. Nitrogen addition to the CCE community increased picoeukaryote chlorophyll a quotas within 24 h, suggesting that nutrient uplift by eddies causes a ‘greening’ effect as well as an increase in phytoplankton biomass. After three days in both the EAC and CCE, diatoms increased in abundance with macronutrient (N, P, Si and iron amendment, whereas haptophytes and phototrophic dinoflagellates declined. Our results indicate that cyclonic eddies increase delivery of nitrogen to the upper ocean to potentially

  17. Occupational exposure to electric fields and induced currents associated with 400 kV substation tasks from different service platforms.

    Science.gov (United States)

    Korpinen, Leena H; Elovaara, Jarmo A; Kuisti, Harri A

    2011-01-01

    The aim of the study was to investigate the occupational exposure to electric fields, average current densities, and average total contact currents at 400 kV substation tasks from different service platforms (main transformer inspection, maintenance of operating device of disconnector, maintenance of operating device of circuit breaker). The average values are calculated over measured periods (about 2.5 min). In many work tasks, the maximum electric field strengths exceeded the action values proposed in the EU Directive 2004/40/EC, but the average electric fields (0.2-24.5 kV/m) were at least 40% lower than the maximum values. The average current densities were 0.1-2.3 mA/m² and the average total contact currents 2.0-143.2 µA, that is, clearly less than the limit values of the EU Directive. The average values of the currents in head and contact currents were 16-68% lower than the maximum values when we compared the average value from all cases in the same substation. In the future it is important to pay attention to the fact that the action and limit values of the EU Directive differ significantly. It is also important to take into account that generally, the workers' exposure to the electric fields, current densities, and total contact currents are obviously lower if we use the average values from a certain measured time period (e.g., 2.5 min) than in the case where exposure is defined with only the help of the maximum values. © 2010 Wiley-Liss, Inc.

  18. Functional interaction between right parietal and bilateral frontal cortices during visual search tasks revealed using functional magnetic imaging and transcranial direct current stimulation.

    Directory of Open Access Journals (Sweden)

    Amanda Ellison

    Full Text Available The existence of a network of brain regions which are activated when one undertakes a difficult visual search task is well established. Two primary nodes on this network are right posterior parietal cortex (rPPC and right frontal eye fields. Both have been shown to be involved in the orientation of attention, but the contingency that the activity of one of these areas has on the other is less clear. We sought to investigate this question by using transcranial direct current stimulation (tDCS to selectively decrease activity in rPPC and then asking participants to perform a visual search task whilst undergoing functional magnetic resonance imaging. Comparison with a condition in which sham tDCS was applied revealed that cathodal tDCS over rPPC causes a selective bilateral decrease in frontal activity when performing a visual search task. This result demonstrates for the first time that premotor regions within the frontal lobe and rPPC are not only necessary to carry out a visual search task, but that they work together to bring about normal function.

  19. Effects of transcranial direct current stimulation of the motor cortex on prefrontal cortex activation during a neuromuscular fatigue task: an fNIRS study.

    Science.gov (United States)

    Muthalib, Makii; Kan, Benjamin; Nosaka, Kazunori; Perrey, Stephane

    2013-01-01

    This study investigated whether manipulation of motor cortex excitability by transcranial direct current stimulation (tDCS) modulates neuromuscular fatigue and functional near-infrared spectroscopy (fNIRS)-derived prefrontal cortex (PFC) activation. Fifteen healthy men (27.7 ± 8.4 years) underwent anodal (2 mA, 10 min) and sham (2 mA, first 30 s only) tDCS delivered to the scalp over the right motor cortex. Subjects initially performed a baseline sustained submaximal (30 % maximal voluntary isometric contraction, MVC) isometric contraction task (SSIT) of the left elbow flexors until task failure, which was followed 50 min later by either an anodal or sham treatment condition, then a subsequent posttreatment SSIT. Endurance time (ET), torque integral (TI), and fNIRS-derived contralateral PFC oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin concentration changes were determined at task failure. Results indicated that during the baseline and posttreatment SSIT, there were no significant differences in TI and ET, and increases in fNIRS-derived PFC activation at task failure were observed similarly regardless of the tDCS conditions. This suggests that the PFC neuronal activation to maintain muscle force production was not modulated by anodal tDCS.

  20. Pilot Task Demand Load During RNAV Approaches

    NARCIS (Netherlands)

    Heiligers, M.M.

    2011-01-01

    The question that started this research was: “Why is approach A more difficult to fly for a pilot than approach B?”. To find an answer to this question, pilots flew a large variety of Area Navigation (RNAV) approaches during several flight simulator and real flight experiments. The results of these

  1. Self-Rated Attentiveness Interacts with Transcranial Direct Current Stimulation and Noise Stimulation in Reaction Time in a Go/No-Go Task.

    Science.gov (United States)

    Sikström, Sverker; Jürgensen, Anna-Maria; Haghighi, Maryam; Månsson, Daniel; Smidelik, David; Habekost, Thomas

    2016-01-01

    Previous research has found that stimulating inattentive people with auditory white noise induces enhancement in cognitive performance. This enhancement is believed to occur due to a statistical phenomenon called stochastic resonance, where noise increases the probability of a signal passing the firing threshold in the neural cells. Here we investigate whether people with low attentiveness benefit to a larger extent than attentive people from stimulation by auditory white noise and transcranial direct current stimulation (tDCS). The results show, for both auditory noise and tDCS stimulation, that the changes in performance relative to nonstimulation correlate with the degree of attentiveness in a Go/No-Go task, but not in a N-back task. These results suggest that the benefit of tDCS may interact with inattentiveness.

  2. Transcranial direct current stimulation (tDCS) facilitates overall visual search response times but does not interact with visual search task factors.

    Science.gov (United States)

    Sung, Kyongje; Gordon, Barry

    2018-01-01

    Whether transcranial direct current stimulation (tDCS) affects mental functions, and how any such effects arise from its neural effects, continue to be debated. We investigated whether tDCS applied over the visual cortex (Oz) with a vertex (Cz) reference might affect response times (RTs) in a visual search task. We also examined whether any significant tDCS effects would interact with task factors (target presence, discrimination difficulty, and stimulus brightness) that are known to selectively influence one or the other of the two information processing stages posited by current models of visual search. Based on additive factor logic, we expected that the pattern of interactions involving a significant tDCS effect could help us colocalize the tDCS effect to one (or both) of the processing stages. In Experiment 1 (n = 12), anodal tDCS improved RTs significantly; cathodal tDCS produced a nonsignificant trend toward improvement. However, there were no interactions between the anodal tDCS effect and target presence or discrimination difficulty. In Experiment 2 (n = 18), we manipulated stimulus brightness along with target presence and discrimination difficulty. Anodal and cathodal tDCS both produced significant improvements in RTs. Again, the tDCS effects did not interact with any of the task factors. In Experiment 3 (n = 16), electrodes were placed at Cz and on the upper arm, to test for a possible effect of incidental stimulation of the motor regions under Cz. No effect of tDCS on RTs was found. These findings strengthen the case for tDCS having real effects on cerebral information processing. However, these effects did not clearly arise from either of the two processing stages of the visual search process. We suggest that this is because tDCS has a DIFFUSE, pervasive action across the task-relevant neuroanatomical region(s), not a discrete effect in terms of information processing stages.

  3. Current fusion plasma theory grant: Task I, Magnetic confinement fusion plasma theory: Final report, December 1, 1987--November 14, 1988

    International Nuclear Information System (INIS)

    Callen, J.D.

    1988-07-01

    The research performed under this grant over the current 11-1/2 month period has concentrated on key tokamak plasma confinement and heating theory issues: extensions of neoclassical MHD; viscosity coefficients and transport; nonlinear resistive MHD simulations of Tokapole II plasmas; ICRF and edge plasma interactions; energy confinement degradation due to macroscopic phenomena; and coordination of a new transport initiative. Progress and publications in these areas are briefly summarized in this report. 21 refs

  4. Maximum power demand cost

    International Nuclear Information System (INIS)

    Biondi, L.

    1998-01-01

    The charging for a service is a supplier's remuneration for the expenses incurred in providing it. There are currently two charges for electricity: consumption and maximum demand. While no problem arises about the former, the issue is more complicated for the latter and the analysis in this article tends to show that the annual charge for maximum demand arbitrarily discriminates among consumer groups, to the disadvantage of some [it

  5. High-definition transcranial direct current stimulation (HD-tDCS) of left dorsolateral prefrontal cortex affects performance in Balloon Analogue Risk Task (BART).

    Science.gov (United States)

    Guo, Heng; Zhang, Zhuoran; Da, Shu; Sheng, Xiaotian; Zhang, Xichao

    2018-02-01

    Studies on risk preferences have long been of great concern and have examined the neural basis underlying risk-based decision making. However, studies using conventional transcranial direct current stimulation (tDCS) revealed that bilateral stimulation could change risk propensity with limited evidence of precisely focalized unilateral high-definition transcranial direct current stimulation (HD-tDCS). The aim of this experiment was to investigate the effect of HD-tDCS focalizing the left dorsal lateral prefrontal cortex (DLPFC) on risk-taking behavior during the Balloon Analogue Risk Task (BART). This study was designed as a between-subject, single-blind, sham-controlled experiment. University students were randomly assigned to three groups: the anodal group (F3 anode, AF3, F1, F5, FC3 returned), the cathodal group (F3 cathodal, AF3, F1, F5, FC3 returned) and the sham group. Subsequently, 1.5-mA 20-min HD-tDCS was applied during the BART, and the Positive Affect and Negative Affect Scale (PANAS), the Sensation Seeking Scale-5 (SSS-5), and the Behavioral Inhibition System and Behavioral Approach System scale (BIS/BAS) were measured as control variables. The cathodal group earned less total money than the sham group, and no significant difference was observed between the anodal group and the sham group. These results showed that, to some extent, focalized unilateral cathodal HD-tDCS on left DLPFC could change performance during risky tasks and diminish risky decision making. Further studies are needed to investigate the dose effect and electrode distribution of HD-tDCS during risky tasks and examine synchronous brain activity to show the neural basis.

  6. Human resource management for a new generation: The professional orientation of young people in the Czech Republic does not match the current labor market Demands

    OpenAIRE

    Švarcová, Jena; Dohnalová, Zuzana

    2012-01-01

    The Czech economy is traditionally focused on technical fields such as engineering, electronics, and automotive industries. Research among students in secondary schools and universities in the Czech Republic however, shows that future generations would choose another profession, according to the classification by Roe, than required by the job market. The demand of the labour market faces a lack of employees, especially in the group of occupations number 4, technologies, which is still the mos...

  7. Intelligence is differentially related to neural effort in the task-positive and the task-negative brain network

    NARCIS (Netherlands)

    Basten, U.; Stelzel, C.; Fiebach, C.J.

    2013-01-01

    Previous studies on individual differences in intelligence and brain activation during cognitive processing focused on brain regions where activation increases with task demands (task-positive network, TPN). Our study additionally considers brain regions where activation decreases with task demands

  8. Demand response in energy markets

    International Nuclear Information System (INIS)

    Skytte, K.; Birk Mortensen, J.

    2004-11-01

    Improving the ability of energy demand to respond to wholesale prices during critical periods of the spot market can reduce the total costs of reliably meeting demand, and the level and volatility of the prices. This fact has lead to a growing interest in the short-run demand response. There has especially been a growing interest in the electricity market where peak-load periods with high spot prices and occasional local blackouts have recently been seen. Market concentration at the supply side can result in even higher peak-load prices. Demand response by shifting demand from peak to base-load periods can counteract the market power in the peak-load. However, demand response has so far been modest since the current short-term price elasticity seems to be small. This is also the case for related markets, for example, green certificates where the demand is determined as a percentage of the power demand, or for heat and natural gas markets. This raises a number of interesting research issues: 1) Demand response in different energy markets, 2) Estimation of price elasticity and flexibility, 3) Stimulation of demand response, 4) Regulation, policy and modelling aspects, 5) Demand response and market power at the supply side, 6) Energy security of supply, 7) Demand response in forward, spot, ancillary service, balance and capacity markets, 8) Demand response in deviated markets, e.g., emission, futures, and green certificate markets, 9) Value of increased demand response, 10) Flexible households. (BA)

  9. Evaluating Virtual Reality and Augmented Reality Training for Industrial Maintenance and Assembly Tasks

    Science.gov (United States)

    Gavish, Nirit; Gutiérrez, Teresa; Webel, Sabine; Rodríguez, Jorge; Peveri, Matteo; Bockholt, Uli; Tecchia, Franco

    2015-01-01

    The current study evaluated the use of virtual reality (VR) and augmented reality (AR) platforms, developed within the scope of the SKILLS Integrated Project, for industrial maintenance and assembly (IMA) tasks training. VR and AR systems are now widely regarded as promising training platforms for complex and highly demanding IMA tasks. However,…

  10. In demand

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, B. [Bridgestone Ltd. (United Kingdom)

    2005-11-01

    The paper explains how good relationships can help alleviate potential tyre shortages. Demand for large dump truck tyres (largely for China) has increased by 50% within 12 months. Bridgestone's manufacturing plants are operating at maximum capacity. The company supplies tyres to all vehicles at Scottish Coal's opencast coal mines. Its Tyre Management System (TMS) supplied free of charge to customers helps maximise tyre life and minimise downtime from data on pressure, tread and general conditions fed into the hand-held TMS computer. 3 photos.

  11. No effect of anodal transcranial direct current stimulation over the motor cortex on response-related ERPs during a conflict task.

    Directory of Open Access Journals (Sweden)

    Alexander Christian Conley

    2016-08-01

    Full Text Available Anodal transcranial direct current stimulation (tDCS over the motor cortex is considered a potential treatment for motor rehabilitation following stroke and other neurological pathologies. However, both the context under which this stimulation is effective and the underlying mechanisms remain to be determined. In this study, we examined the mechanisms by which anodal tDCS may affect motor performance by recording event-related potentials (ERPs during a cued go/nogo task after anodal tDCS over dominant M1 in young adults (Experiment 1 and both dominant and non-dominant M1 in old adults (Experiment 2. In both experiments, anodal tDCS had no effect on either response time or response-related ERPs, including the cue-locked contingent negative variation (CNV and both target-locked and response-locked lateralised readiness potentials (LRP. Bayesian model selection analyses showed that, for all measures, the null effects model was stronger than a model including anodal tDCS vs. sham. We conclude that anodal tDCS has no effect on response time or response-related ERPs during a cued go/nogo task in either young or old adults.

  12. [Was the current surplus of neurosurgeons predictable in 2009? Analysis of the situation based on the Report of supply and demand of medical specialists in Spain (2008-2025)].

    Science.gov (United States)

    Martín-Láez, Rubén; Ibáñez, Javier; Lagares, Alfonso; Fernández-Alén, José; Díez-Lobato, Ramiro

    2012-11-01

    In 2009 the Spanish Ministry of Health (SMH) published the report of supply and demand of medical specialists in Spain (2008-2025), in which our specialty was considered as presenting a moderate deficit of consultants. However, Spanish neurosurgery is currently in a situation of having a surplus of neurosurgeons. To determine whether it was possible to predict the current excess of neurosurgeons in 2009 and to forecast the most likely perspective of supply and demand in 2017. Raw data extracted from the SMH report, information on the ages of the Spanish neurosurgeons obtained from the study performed by our Board of Directors in 2001, and annual mortality rates for different age ranges provided by the National Institute of Statistics, were used to predict the evolution of supply and demand of neurosurgeons for the periods 2008-2012 and 2013-2017. The current situation of an excess of specialists was predictable in 2009, and if appropriate measures are not taken, a surplus of more than 100 neurosurgeons is likely in 2017, with an unemployment rate above 26% in the worst scenario. In order to match the actual and future demand of specialists, it is necessary and urgent to reduce the number of neurosurgical in-training positions. To achieve this goal, it is essential to obtain periodical and up-to-date structural information of the different Neurosurgery Departments and Units, and to revisit the accreditation terms of the more than fifty current teaching units. Copyright © 2012 Sociedad Española de Neurocirugía. Published by Elsevier España. All rights reserved.

  13. Executive Function Is Necessary for Perspective Selection, Not Level-1 Visual Perspective Calculation: Evidence from a Dual-Task Study of Adults

    Science.gov (United States)

    Qureshi, Adam W.; Apperly, Ian A.; Samson, Dana

    2010-01-01

    Previous research suggests that perspective-taking and other "theory of mind" processes may be cognitively demanding for adult participants, and may be disrupted by concurrent performance of a secondary task. In the current study, a Level-1 visual perspective task was administered to 32 adults using a dual-task paradigm in which the secondary task…

  14. Transcranial Direct Current Stimulation (tDCS) Targeting Left Dorsolateral Prefrontal Cortex Modulates Task-Induced Acute Pain in Healthy Volunteers.

    Science.gov (United States)

    Mariano, Timothy Y; Van't Wout, Mascha; Garnaat, Sarah L; Rasmussen, Steven A; Greenberg, Benjamin D

    2016-04-01

    Current chronic pain treatments target nociception rather than affective "suffering" and its associated functional and psychiatric comorbidities. The left dorsolateral prefrontal cortex (DLPFC) has been implicated in affective, cognitive, and attentional aspects of pain and is a primary target of neuromodulation for affective disorders. Transcranial direct current stimulation (tDCS) can non-invasively modulate cortical activity. The present study tests whether anodal tDCS targeting the left DLPFC will increase tolerability of acute painful stimuli vs cathodal tDCS. Forty tDCS-naive healthy volunteers received anodal and cathodal stimulation targeting the left DLPFC in two randomized and counterbalanced sessions. During stimulation, each participant performed cold pressor (CP) and breath holding (BH) tasks. We measured pain intensity with the Defense and Veterans Pain Rating Scale (DVPRS) before and after each task. Mixed ANOVA revealed no main effect of stimulation polarity for mean CP threshold, tolerance, or endurance, or mean BH time (allP > 0.27). However, DVPRS rise associated with CP was significantly smaller with anodal vs cathodal tDCS (P = 0.024). We further observed a significant tDCS polarity × stimulation order interaction (P = 0.042) on CP threshold, suggesting task sensitization. Although our results do not suggest that polarity of tDCS targeting the left DLPFC differentially modulates the tolerability of CP- and BH-related pain distress in healthy volunteers, there was a significant effect on DVPRS pain ratings. This contrasts with our previous findings that tDCS targeting the left dorsal anterior cingulate cortex showed a trend toward higher mean CP tolerance with cathodal vs anodal stimulation. The present results may suggest tDCS-related effects on nociception or DLPFC-mediated attention, or preferential modulation of the affective valence of pain as captured by the DVPRS. Sham-controlled clinical studies are needed. © 2015

  15. Review of current Southern California edison load management programs and proposal for a new market-driven, mass-market, demand-response program

    Energy Technology Data Exchange (ETDEWEB)

    Weller, G.H.

    2002-01-01

    Utility load management programs, including direct load control and interruptible load programs, constitute a large installed base of controllable loads that are employed by utilities as system reliability resources. In response to energy supply shortfalls expected during the summer of 2001, the California Public Utilities Commission in spring 2001 authorized new utility load management programs as well as revisions to existing programs. This report provides an independent review of the designs of these new programs for a large utility (Southern California Edison) and suggests possible improvements to enhance the price responsiveness of the customer actions influenced by these programs. The report also proposes a new program to elicit a mass-market demand response to utility price signals.

  16. Driving after brain injury: Does dual-task modality matter?

    Science.gov (United States)

    Vickers, Kayci L; Schultheis, Maria T; Manning, Kevin J

    2018-01-01

    Virtual reality technology allows neuropsychologists to examine complex, real-world behaviors with high ecological validity and can provide an understanding of the impact of demanding dual-tasks on driving performance. We hypothesized that a task imposing high cognitive and physical demands (coin-sorting) would result in the greatest reduction in driving maintenance performance. Twenty participants with acquired brain injury and 28 healthy controls were included in the current study. All participants were licensed and drove regularly. Participants completed two standardized VRDS drives: (1) a baseline drive with no distractions, and (2) the same route with three, counterbalanced dual-tasks representing differing demands. A series of 3 (Task)×2 (Group) ANOVAs revealed that the ABI group tended to go slower than the HC group in the presence of a dual-task, F (1, 111) = 6.24, p = 0.01. Importantly, the ABI group also showed greater variability in speed, F (1, 110) = 10.97, p < 0.01, and lane position, F (1, 108) = 7.81, p < 0.01, an effect driven by dual-tasks with both a cognitive and motor demand. These results indicate that long-term driving difficulties following ABI are subtle and likely due to reduced cognitive resources.

  17. Cognitive Modeling for Closed-Loop Task Mitigation, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — As flightdeck equipment becomes more sophisticated and complex, operations become significantly more cognitively demanding. When tasks demands exceed the operator's...

  18. Manipulating perceptual parameters in a continuous performance task.

    Science.gov (United States)

    Shalev, Nir; Humphreys, Glyn; Demeyere, Nele

    2018-02-01

    Sustained attention (SA) is among the most studied faculties of human cognition, and thought to be crucial for many aspects of behavior. Measuring SA often relies on performance on a continuous, low-demanding task. Such continuous performance tasks (CPTs) have many variations, and sustained attention is typically estimated based on variability in reaction times. While relying on reaction times may be useful in some cases, it can pose a challenge when working with clinical populations. To increase interpersonal variability in task parameters that do not rely on speed, researchers have increased demands for memory and response inhibition. These approaches, however, may be confounded when used to assess populations that suffer from multiple cognitive deficits. In the current study, we propose a new approach for increasing task variability by increasing the attentional demands. In order to do so, we created a new variation of a CPT - a masked version, where inattention is more likely to cause misidentifying a target. After establishing that masking indeed decreases target detection, we further investigated which task parameter may influence response biases. To do so, we contrasted two versions of the CPT with different target/distractor ratio. We then established how perceptual parameters can be controlled independently in a CPT. Following the experimental manipulations, we tested the MCCPT with aging controls and chronic stroke patients to assure the task can be used with target populations. The results confirm the MCCPT as a task providing high sensitivity without relying on reaction speed, and feasible for patients.

  19. Assessing the Utility of a Demand Assessment for Functional Analysis

    Science.gov (United States)

    Roscoe, Eileen M.; Rooker, Griffin W.; Pence, Sacha T.; Longworth, Lynlea J.

    2009-01-01

    We evaluated the utility of an assessment for identifying tasks for the functional analysis demand condition with 4 individuals who had been diagnosed with autism. During the demand assessment, a therapist presented a variety of tasks, and observers measured problem behavior and compliance to identify demands associated with low levels of…

  20. Brain Oscillatory and Hemodynamic Activity in a Bimanual Coordination Task Following Transcranial Alternating Current Stimulation (tACS): A Combined EEG-fNIRS Study.

    Science.gov (United States)

    Berger, Alisa; Pixa, Nils H; Steinberg, Fabian; Doppelmayr, Michael

    2018-01-01

    Motor control is associated with synchronized oscillatory activity at alpha (8-12 Hz) and beta (12-30 Hz) frequencies in a cerebello-thalamo-cortical network. Previous studies demonstrated that transcranial alternating current stimulation (tACS) is capable of entraining ongoing oscillatory activity while also modulating motor control. However, the modulatory effects of tACS on both motor control and its underlying electro- and neurophysiological mechanisms remain ambiguous. Thus, the purpose of this study was to contribute to gathering neurophysiological knowledge regarding tACS effects by investigating the after-effects of 10 Hz tACS and 20 Hz tACS at parietal brain areas on bimanual coordination and its concurrent oscillatory and hemodynamic activity. Twenty-four right-handed healthy volunteers (12 females) aged between 18 and 30 ( M = 22.35 ± 3.62) participated in the study and performed a coordination task requiring bimanual movements. Concurrent to bimanual motor training, participants received either 10 Hz tACS, 20 Hz tACS or a sham stimulation over the parietal cortex (at P3/P4 electrode positions) for 20 min via small gel electrodes (3,14 cm 2 Ag/AgCl, amperage = 1 mA). Before and three time-points after tACS (immediately, 30 min and 1 day), bimanual coordination performance was assessed. Oscillatory activities were measured by electroencephalography (EEG) and hemodynamic changes were examined using functional near-infrared spectroscopy (fNIRS). Improvements of bimanual coordination performance were not differently between groups, thus, no tACS-specific effect on bimanual coordination performance emerged. However, physiological measures during the task revealed significant increases in parietal alpha activity immediately following 10 Hz tACS and 20 Hz tACS which were accompanied by significant decreases of Hboxy concentration in the right hemispheric motor cortex compared to the sham group. Based on the physiological responses, we conclude that t

  1. Brain Oscillatory and Hemodynamic Activity in a Bimanual Coordination Task Following Transcranial Alternating Current Stimulation (tACS: A Combined EEG-fNIRS Study

    Directory of Open Access Journals (Sweden)

    Alisa Berger

    2018-04-01

    Full Text Available Motor control is associated with synchronized oscillatory activity at alpha (8–12 Hz and beta (12–30 Hz frequencies in a cerebello-thalamo-cortical network. Previous studies demonstrated that transcranial alternating current stimulation (tACS is capable of entraining ongoing oscillatory activity while also modulating motor control. However, the modulatory effects of tACS on both motor control and its underlying electro- and neurophysiological mechanisms remain ambiguous. Thus, the purpose of this study was to contribute to gathering neurophysiological knowledge regarding tACS effects by investigating the after-effects of 10 Hz tACS and 20 Hz tACS at parietal brain areas on bimanual coordination and its concurrent oscillatory and hemodynamic activity. Twenty-four right-handed healthy volunteers (12 females aged between 18 and 30 (M = 22.35 ± 3.62 participated in the study and performed a coordination task requiring bimanual movements. Concurrent to bimanual motor training, participants received either 10 Hz tACS, 20 Hz tACS or a sham stimulation over the parietal cortex (at P3/P4 electrode positions for 20 min via small gel electrodes (3,14 cm2 Ag/AgCl, amperage = 1 mA. Before and three time-points after tACS (immediately, 30 min and 1 day, bimanual coordination performance was assessed. Oscillatory activities were measured by electroencephalography (EEG and hemodynamic changes were examined using functional near-infrared spectroscopy (fNIRS. Improvements of bimanual coordination performance were not differently between groups, thus, no tACS-specific effect on bimanual coordination performance emerged. However, physiological measures during the task revealed significant increases in parietal alpha activity immediately following 10 Hz tACS and 20 Hz tACS which were accompanied by significant decreases of Hboxy concentration in the right hemispheric motor cortex compared to the sham group. Based on the physiological responses, we conclude that

  2. Demands Set Upon Modern Cartographic Visualization

    Directory of Open Access Journals (Sweden)

    Stanislav Frangeš

    2007-05-01

    Full Text Available Scientific cartography has the task to develop and research new methods of cartographic visualization. General demands are set upon modern cartographic visualization, which encompasses digital cartography and computer graphics: legibility, clearness, accuracy, plainness and aesthetics. In this paper, it is explained in detail what demands should be met in order to satisfy the general demands set. In order to satisfy the demand of legibility, one should respect conditions of minimal sizes, appropriate graphical density and better differentiation of known features. Demand of clearness needs to be met by fulfilling conditions of simplicity, contrasting quality and layer arrangement of cartographic representation. Accuracy, as the demand on cartographic visualization, can be divided into positioning accuracy and accuracy signs. For fulfilling the demand of plainness, the conditions of symbolism, traditionalism and hierarchic organization should be met. Demand of aesthetics will be met if the conditions of beauty and harmony are fulfilled.

  3. Psychopathology and tobacco demand.

    Science.gov (United States)

    Farris, Samantha G; Aston, Elizabeth R; Zvolensky, Michael J; Abrantes, Ana M; Metrik, Jane

    2017-08-01

    Behavioral economic measurement of the relative value of tobacco (Cigarette Purchase Task; CPT) is used to examine individual differences in motivation for tobacco under certain contexts. Smokers with psychopathology, relative to those without, may demonstrate stronger demand for tobacco following a period of smoking deprivation, which could account for disparate rates of smoking and cessation among this subgroup. Participants (n=111) were community-recruited adult daily smokers who completed the CPT after a deprivation period of approximately 60min. Presence of psychopathology was assessed via clinical interview; 40.5% (n=45) of the sample met criteria for past-year psychological diagnosis. Specifically, 31.5% (n=35) had an emotional disorder (anxiety/depressive disorder), 17.1% (n=19) had a substance use disorder, and 19.1% of the sample had more than one disorder. Smokers with any psychopathology showed significantly higher intensity (demand at unrestricted cost; $0) and O max (peak expenditure for a drug) relative to smokers with no psychopathology. Intensity was significantly higher among smokers with an emotional disorder compared to those without. Smokers with a substance use disorder showed significantly higher intensity and O max , and lower elasticity, reflecting greater insensitivity to price increases. Having≥2 disorders was associated with higher intensity relative to having 1 or no disorders. Findings suggest that presence of psychopathology may be associated with greater and more persistent motivation to smoke. Future work is needed to explore the mechanism linking psychopathology to tobacco demand. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Automatic-heuristic and executive-analytic processing during reasoning: Chronometric and dual-task considerations.

    Science.gov (United States)

    De Neys, Wim

    2006-06-01

    Human reasoning has been shown to overly rely on intuitive, heuristic processing instead of a more demanding analytic inference process. Four experiments tested the central claim of current dual-process theories that analytic operations involve time-consuming executive processing whereas the heuristic system would operate automatically. Participants solved conjunction fallacy problems and indicative and deontic selection tasks. Experiment 1 established that making correct analytic inferences demanded more processing time than did making heuristic inferences. Experiment 2 showed that burdening the executive resources with an attention-demanding secondary task decreased correct, analytic responding and boosted the rate of conjunction fallacies and indicative matching card selections. Results were replicated in Experiments 3 and 4 with a different secondary-task procedure. Involvement of executive resources for the deontic selection task was less clear. Findings validate basic processing assumptions of the dual-process framework and complete the correlational research programme of K. E. Stanovich and R. F. West (2000).

  5. Demand Response as a System Reliability Resource

    Energy Technology Data Exchange (ETDEWEB)

    Eto, Joseph H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Lewis, Nancy Jo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Watson, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Kiliccote, Sila [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Auslander, David [Univ. of California, Berkeley, CA (United States); Paprotny, Igor [Univ. of California, Berkeley, CA (United States); Makarov, Yuri [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2012-12-31

    The Demand Response as a System Reliability Resource project consists of six technical tasks: • Task 2.1. Test Plan and Conduct Tests: Contingency Reserves Demand Response (DR) Demonstration—a pioneering demonstration of how existing utility load-management assets can provide an important electricity system reliability resource known as contingency reserve. • Task 2.2. Participation in Electric Power Research Institute (EPRI) IntelliGrid—technical assistance to the EPRI IntelliGrid team in developing use cases and other high-level requirements for the architecture. • Task 2.3. Research, Development, and Demonstration (RD&D) Planning for Demand Response Technology Development—technical support to the Public Interest Energy Research (PIER) Program on five topics: Sub-task 1. PIER Smart Grid RD&D Planning Document; Sub-task 2. System Dynamics of Programmable Controllable Thermostats; Sub-task 3. California Independent System Operator (California ISO) DR Use Cases; Sub-task 4. California ISO Telemetry Requirements; and Sub-task 5. Design of a Building Load Data Storage Platform. • Task 2.4. Time Value of Demand Response—research that will enable California ISO to take better account of the speed of the resources that it deploys to ensure compliance with reliability rules for frequency control. • Task 2.5. System Integration and Market Research: Southern California Edison (SCE)—research and technical support for efforts led by SCE to conduct demand response pilot demonstrations to provide a contingency reserve service (known as non-spinning reserve) through a targeted sub-population of aggregated residential and small commercial customers enrolled in SCE’s traditional air conditioning (AC) load cycling program, the Summer Discount Plan. • Task 2.6. Demonstrate Demand Response Technologies: Pacific Gas and Electric (PG&E)—research and technical support for efforts led by PG&E to conduct a demand response pilot demonstration to provide non

  6. Performance on verbal and low-verbal false belief tasks: evidence from children with Williams syndrome.

    Science.gov (United States)

    Van Herwegen, Jo; Dimitriou, Dagmara; Rundblad, Gabriella

    2013-01-01

    Previous studies that have investigated the relationship between performance on theory of mind (ToM) tasks and verbal abilities in individuals with Williams syndrome (WS) have reported contradictory findings with some showing that language abilities aid performance on ToM tasks while others have found that participants with WS fail these tasks because of their verbal demands. The current study investigated this relationship again comparing performance on a classical change-location task to two newly developed low-verbal tasks, one change-location task and one unexpected content task. Thirty children with WS (aged 5-17;01 years) and 30 typically developing (TD) children (aged between 2;10 years and 9;09 years), who were matched for vocabulary comprehension scores were included in the study. Although performance in the WS group was significantly poorer compared to the TD group on all three tasks, performance was not predicted by their receptive vocabulary or grammatical ability scores. In addition, ToM abilities in both groups depended on the cognitive demands of the task at hand. This finding shows that performance on ToM tasks in WS is not necessarily hindered by their delayed language abilities but rather by the task administered. This could potentially affect the diagnosis of developmental disorders, such as Autism Spectrum Disorders, and comparison of ToM abilities across developmental disorders. Readers of this article should be able to (1) describe the current state of theory of mind research in Williams syndrome, (2) identify which cognitive abilities might explain performance on theory of mind tasks in both typically developing children and in children with Williams syndrome, and (3) interpret the importance of task demands when assessing children's theory of mind abilities. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Strong demand for natural uranium

    International Nuclear Information System (INIS)

    Kalinowski, P.

    1975-01-01

    The Deutsches Atomforum and the task group 'fuel elements' of the Kerntechnische Gesellschaft had organized an international two-day symposium in Mainz on natural uranium supply which was attended by 250 experts from 20 countries. The four main themes were: Demand for natural uranium, uranium deposits and uranium production, attitude of the uranium producing countries, and energy policy of the industrial nations. (orig./AK) [de

  8. Designing for dynamic task allocation

    NARCIS (Netherlands)

    Dongen, van K.; Maanen, van P.P.

    2005-01-01

    Future platforms are envisioned in which human-machine teams are able to share and trade tasks as demands in situations change. It seems that human-machine coordination has not received the attention it deserves by past and present approaches to task allocation. In this paper a simple way to make

  9. Offshore petroleum engineering task force report

    International Nuclear Information System (INIS)

    Ruelokke, M.

    1999-05-01

    The Offshore Petroleum Engineering Task Force was established in July 1998 in response to concerns about Newfoundland and Labrador's share of offshore petroleum engineering activity, with the aim of determining the current capability of the local sector, the demand for such companies and individuals until the year 2010, their capability to grow over that time-frame, and requirements in order to achieve that growth. The report summarizes the analysis undertaken by the Task Force as well as the conclusions it reached and associated recommendations. Section two provides an overview of the offshore engineering activity, including its origins, structure, and key success factors, and its also provides a profile of the industry, internationally, in Canada and in Newfoundland. Section three presents an analysis of the future demand for offshore engineering in Newfoundland until 2010, based on three development scenarios. Section four based on a Consulting Engineers of Newfoundland and Labrador (CENL) survey, establishes the present offshore engineering capacity and capabilities within the province. Section five examines current education and training programs and their ability to respond to future demands. Section six summarizes the conclusions of the analysis and presents recommendations designed to facilitate and promote the development of the local offshore engineering industry. 6 figs

  10. Demand scenarios, worldwide

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, A [Massachusetts Inst. of Technology, Center for Technology, Policy and Industrial Development and the MIT Joint Program on the Science and Policy of Global Change, Cambridge, MA (United States)

    1996-11-01

    Existing methods are inadequate for developing aggregate (regional and global) and long-term (several decades) passenger transport demand scenarios, since they are mainly based on simple extensions of current patterns rather than causal relationships that account for the competition among transport modes (aircraft, automobiles, buses and trains) to provide transport services. The demand scenario presented in this paper is based on two empirically proven invariances of human behavior. First, transport accounts for 10 to 15 percent of household total expenditures for those owning an automobile, and around 5 percent for non-motorized households on average (travel money budget). Second, the mean time spent traveling is approximately one hour per capita per day (travel time budget). These two budgets constraints determine the dynamics of the scenario: rising income increases per capita expenditure on travel which, in turn, increase demand for mobility. Limited travel time constraints travelers to shift to faster transport systems. The scenario is initiated with the first integrated historical data set on traffic volume in 11 world regions and the globe from 1960 to 1990 for all major modes of motorized transport. World average per capita traffic volume, which was 1,800 kilometers in 1960 and 4,2090 in 1990, is estimated to rise to 7,900 kilometers in 2020 - given a modest average increase in Gross World Product of 1.9% per year. Higher economic growth rates in Asian regions result in an increase in regional per capita traffic volume up to a factor of 5.3 from 1990 levels. Modal splits continue shifting to more flexible and faster modes of transport. At one point, passenger cars can no longer satisfy the increasing demand for speed (i.e. rising mobility within a fixed time budget). In North America it is estimated that the absolute traffic volume of automobiles will gradually decline starting in the 2010s. (author) 13 figs., 6 tabs., 35 refs.

  11. Market architecture and power demand management

    International Nuclear Information System (INIS)

    Rious, Vincent; Roques, Fabien

    2014-12-01

    Demand response is a cornerstone problem in electricity markets considering climate change constraint. Most liberalized electricity markets have a poor track record at developing demand response. In Europe, different models are considered for demand response, from a development under a regulated regime to a development under competitive perspectives. In this paper, focusing on demand response for mid-size and small consumers, we investigate which types of market signals should be sent to demand response aggregators to see demand response emerge as a competitive activity. Using data from the French power system over eight years, we compare the possible market design options to allow demand response to develop. Our simulations demonstrate that with the current market rules, demand response is not a profitable activity in the French electricity industry. Introducing a capacity remuneration could bring additional revenues to demand response aggregators if the power system has no over-capacity

  12. Dietetics supply and demand: 2010-2020.

    Science.gov (United States)

    Hooker, Roderick S; Williams, James H; Papneja, Jesleen; Sen, Namrata; Hogan, Paul

    2012-03-01

    The Academy of Nutrition and Dietetics, in conjunction with the Commission on Dietetic Registration (CDR), invited The Lewin Group to undertake an analysis of the dietetics workforce. The purpose of the workforce study was to develop a model that can project the supply and demand for both registered dietitians (RDs) and dietetic technicians, registered (DTRs) (collectively referred to as CDR-credentialed dietetics practitioners) as the result of various key drivers of change. The research team was asked to quantify key market factors where possible and to project likely paths for the evolution of workforce supply and demand, as well as to assess the implications of the findings. This article drew on the survey research conducted by Readex Research and futurist organizations such as Signature i and Trend Spot Consulting. Furthermore, members of the Dietetics Workforce Demand Task Force were a source of institutional and clinical information relevant to the credentialed dietetics workforce--including their opinions and judgment of the current state of the health care market for dietetic services, its future state, and factors affecting it, which were useful and were integrated with the objective sources of data. The model is flexible and accommodates the variation in how RDs and DTRs function in diverse practice areas. For purposes of this study and model, the dietetics workforce is composed of RDs and DTRs. This report presents the results of this workforce study and the methodology used to calculate the projected dietetics workforce supply and demand. The projections are based on historical trends and estimated future changes. Key findings of the study included the following: • The average age of all CDR-credentialed dietetics practitioners in baseline supply (2010) is 44 years; approximately 96% are women. • Approximately 55% of CDR-credentialed dietetics practitioners work in clinical dietetics. • The annual growth rate of supply of CDR

  13. Demand curves for hypothetical cocaine in cocaine-dependent individuals.

    Science.gov (United States)

    Bruner, Natalie R; Johnson, Matthew W

    2014-03-01

    Drug purchasing tasks have been successfully used to examine demand for hypothetical consumption of abused drugs including heroin, nicotine, and alcohol. In these tasks, drug users make hypothetical choices whether to buy drugs, and if so, at what quantity, at various potential prices. These tasks allow for behavioral economic assessment of that drug's intensity of demand (preferred level of consumption at extremely low prices) and demand elasticity (sensitivity of consumption to price), among other metrics. However, a purchasing task for cocaine in cocaine-dependent individuals has not been investigated. This study examined a novel Cocaine Purchasing Task and the relation between resulting demand metrics and self-reported cocaine use data. Participants completed a questionnaire assessing hypothetical purchases of cocaine units at prices ranging from $0.01 to $1,000. Demand curves were generated from responses on the Cocaine Purchasing Task. Correlations compared metrics from the demand curve to measures of real-world cocaine use. Group and individual data were well modeled by a demand curve function. The validity of the Cocaine Purchasing Task was supported by a significant correlation between the demand curve metrics of demand intensity and O max (determined from Cocaine Purchasing Task data) and self-reported measures of cocaine use. Partial correlations revealed that after controlling for demand intensity, demand elasticity and the related measure, P max, were significantly correlated with real-world cocaine use. Results indicate that the Cocaine Purchasing Task produces orderly demand curve data, and that these data relate to real-world measures of cocaine use.

  14. Decoding task-based attentional modulation during face categorization.

    Science.gov (United States)

    Chiu, Yu-Chin; Esterman, Michael; Han, Yuefeng; Rosen, Heather; Yantis, Steven

    2011-05-01

    Attention is a neurocognitive mechanism that selects task-relevant sensory or mnemonic information to achieve current behavioral goals. Attentional modulation of cortical activity has been observed when attention is directed to specific locations, features, or objects. However, little is known about how high-level categorization task set modulates perceptual representations. In the current study, observers categorized faces by gender (male vs. female) or race (Asian vs. White). Each face was perceptually ambiguous in both dimensions, such that categorization of one dimension demanded selective attention to task-relevant information within the face. We used multivoxel pattern classification to show that task-specific modulations evoke reliably distinct spatial patterns of activity within three face-selective cortical regions (right fusiform face area and bilateral occipital face areas). This result suggests that patterns of activity in these regions reflect not only stimulus-specific (i.e., faces vs. houses) responses but also task-specific (i.e., race vs. gender) attentional modulation. Furthermore, exploratory whole-brain multivoxel pattern classification (using a searchlight procedure) revealed a network of dorsal fronto-parietal regions (left middle frontal gyrus and left inferior and superior parietal lobule) that also exhibit distinct patterns for the two task sets, suggesting that these regions may represent abstract goals during high-level categorization tasks.

  15. Meeting increased demand.

    Science.gov (United States)

    Blair, Andrew

    2004-07-01

    New Zealand is a little country with a little economy but with a population that's rapidly aging. New Zealand's population is only 4.3 million people. It's GDP is only $US58.6 billion (2002). New Zealand's expenditure on health as a percentage of GDP is not out of line with that of other countries. As a nation we have been increasing expenditure on health over recent years. In 1990 we spent 7% of GDP on health. In 1995 that increased to 7.65% and is now 8.3%. However, in per capita terms our expenditure on health does not compare so well with like countries. The size of New Zealand's economy is restricting what our country spends on health. Health is already the second highest demand on the New Zealand tax dollar. The tolerance of New Zealanders would be challenged if a Government attempted to increase taxes further to meet the growing demands for expenditure on health, but at the same time the population's expectations are increasing. This is the challenging situation we face today. What lies ahead? Like all industrialized countries New Zealand is facing an aging population. The population below age 40 is decreasing, but it is increasing significantly over that age. 16% of the population is currently aged over 60. By 2051 this proportion will almost double to just over 31%. Coupled with the aging population is increased awareness and expectations, as access to options for treatment and technology becomes readily accessible to the population through such media as the internet. The extent of the impact of the aging population can be clearly represented by focusing on one specialty such as orthopaedics. The New Zealand Orthopaecic Association undertook a study in July 2003 which concluded (among other things) that as a result of the projected aging of the population, over the next 50 years: Musculo-skeletal operations will increase by over 30%. The number of hip replacements will nearly double. The incidence of osteoporosis will increase by a massive 201%. The number

  16. Criteria for demand response systems

    NARCIS (Netherlands)

    Lampropoulos, I.; Kling, W.L.; Bosch, van den P.P.J.; Ribeiro, P.F.; Berg, van den J.

    2013-01-01

    The topic of demand side management is currently becoming more important than ever, in parallel with the further deregulation of the electricity sector, and the increasing integration of renewable energy sources. A historical review of automation integration in power system control assists in

  17. On-Demand Telemetry

    Data.gov (United States)

    National Aeronautics and Space Administration — AFRC has previously investigated the use of Network Based Telemetry. We will be building on that research to enable On-Demand Telemetry. On-Demand Telemetry is a way...

  18. Money Demand in Latvia

    OpenAIRE

    Ivars Tillers

    2004-01-01

    The econometric analysis of the demand for broad money in Latvia suggests a stable relationship of money demand. The analysis of parameter exogeneity indicates that the equilibrium adjustment is driven solely by the changes in the amount of money. The demand for money in Latvia is characterised by relatively high income elasticity typical for the economy in a monetary expansion phase. Due to stability, close fit of the money demand function and rapid equilibrium adjustment, broad money aggreg...

  19. Active listening: task-dependent plasticity of spectrotemporal receptive fields in primary auditory cortex.

    Science.gov (United States)

    Fritz, Jonathan; Elhilali, Mounya; Shamma, Shihab

    2005-08-01

    Listening is an active process in which attentive focus on salient acoustic features in auditory tasks can influence receptive field properties of cortical neurons. Recent studies showing rapid task-related changes in neuronal spectrotemporal receptive fields (STRFs) in primary auditory cortex of the behaving ferret are reviewed in the context of current research on cortical plasticity. Ferrets were trained on spectral tasks, including tone detection and two-tone discrimination, and on temporal tasks, including gap detection and click-rate discrimination. STRF changes could be measured on-line during task performance and occurred within minutes of task onset. During spectral tasks, there were specific spectral changes (enhanced response to tonal target frequency in tone detection and discrimination, suppressed response to tonal reference frequency in tone discrimination). However, only in the temporal tasks, the STRF was changed along the temporal dimension by sharpening temporal dynamics. In ferrets trained on multiple tasks, distinctive and task-specific STRF changes could be observed in the same cortical neurons in successive behavioral sessions. These results suggest that rapid task-related plasticity is an ongoing process that occurs at a network and single unit level as the animal switches between different tasks and dynamically adapts cortical STRFs in response to changing acoustic demands.

  20. Four methodologies to improve healthcare demand forecasting.

    Science.gov (United States)

    Côté, M J; Tucker, S L

    2001-05-01

    Forecasting demand for health services is an important step in managerial decision making for all healthcare organizations. This task, which often is assumed by financial managers, first requires the compilation and examination of historical information. Although many quantitative forecasting methods exist, four common methods of forecasting are percent adjustment, 12-month moving average, trendline, and seasonalized forecast. These four methods are all based upon the organization's recent historical demand. Healthcare financial managers who want to project demand for healthcare services in their facility should understand the advantages and disadvantages of each method and then select the method that will best meet the organization's needs.

  1. Electricity demand forecasting techniques

    International Nuclear Information System (INIS)

    Gnanalingam, K.

    1994-01-01

    Electricity demand forecasting plays an important role in power generation. The two areas of data that have to be forecasted in a power system are peak demand which determines the capacity (MW) of the plant required and annual energy demand (GWH). Methods used in electricity demand forecasting include time trend analysis and econometric methods. In forecasting, identification of manpower demand, identification of key planning factors, decision on planning horizon, differentiation between prediction and projection (i.e. development of different scenarios) and choosing from different forecasting techniques are important

  2. Demand-Side Flexibility for Energy Transitions: Ensuring the Competitive Development of Demand Response Options

    OpenAIRE

    Nursimulu, Anjali; Florin, Marie-Valentine; Vuille, François

    2015-01-01

    This report provides an overview of the current debates about demand response development, focusing primarily on Europe, with some comparisons to the United States. ‘Demand response’ includes strategies that involve end-use customers adapting or altering their electricity demand in response to grid conditions or market prices. It is viewed as a multi-purpose power-system resource that enhances the energy system’s capacity to cope with increasing demand, rising costs of conventional transmissi...

  3. Knowledge acquisition and interface design for learning on demand systems

    Science.gov (United States)

    Nelson, Wayne A.

    1993-01-01

    The rapid changes in our world precipitated by technology have created new problems and new challenges for education and training. A knowledge 'explosion' is occurring as our society moves toward a service oriented economy that relies on information as the major resource. Complex computer systems are beginning to dominate the workplace, causing alarming growth and change in many fields. The rapidly changing nature of the workplace, especially in fields related to information technology, requires that our knowledge be updated constantly. This characteristic of modern society poses seemingly unsolvable instructional problems involving coverage and obsolescence. The sheer amount of information to be learned is rapidly increasing, while at the same time some information becomes obsolete in light of new information. Education, therefore, must become a lifelong process that features learning of new material and skills as needed in relation to the job to be done. Because of the problems cited above, the current model of learning in advance may no longer be feasible in our high-technology world. In many cases, learning in advance is impossible because there are simply too many things to learn. In addition, learning in advance can be time consuming, and often results in decontextualized knowledge that does not readily transfer to the work environment. The large and growing discrepancy between the amount of potentially relevant knowledge available and the amount a person can know and remember makes learning on demand an important alternative to current instructional practices. Learning on demand takes place whenever an individual must learn something new in order to perform a task or make a decision. Learning on demand is a promising approach for addressing the problems of coverage and obsolescence because learning is contextualized and integrated into the task environment rather than being relegated to a separate phase that precedes work. Learning on demand allows learners

  4. Supplies should match growing demand

    International Nuclear Information System (INIS)

    Rasmusen, H.J.

    1997-01-01

    The natural gas industry is currently enjoying healthy growth prospects. Not only is the demand for natural gas steadily growing; the outlook for increasing gas reserves is promising as well. The success of natural gas in the marketplace reflects, on one hand, continuous attention paid to public and customer requirements and, on the other hand, the ability of the gas industry to direct technological developments toward the increasing public demand for gas at competitive market prices supplied in a reliable, safe and environmentally friendly manner. In the past, the gas industry has been involved in the development of technologies for everything from gas production to the end user and from borehole to burner tip, and the author believes that the industry must continue or even increase its emphasis on technology in the future in order to capture new market opportunities. He explains this by looking at the supply side, the demand side and the structural side of the business

  5. Stability of Money Demand Function in Pakistan

    Directory of Open Access Journals (Sweden)

    Haroon Sarwar

    2013-09-01

    Full Text Available The role, which money demand function plays in monetary policy formulation has attracted a lot of research studies to analyze this macroeconomic phenomenon. In the wake of current global and local economic and political upheavals, it is imperative to revisit the stability of money demand function. The study used the time series data and applied latest econometric techniques to find out the long run and short run money demand relationship. Moreover, all the three official monetary aggregates were used for finding out the most stable monetary demand relationship, which could provide correct signals for monetary policy formulation. The study found that broader monetary aggregate (M2 was the proper aggregate, which provided stable money demand function for Pakistan. The real GDP was positively related to the demand for real balances, while opportunity cost of money was negatively related. The study found that the role of financial innovation, in explaining the demand for money warrants attention in formulating monetary policy.

  6. Demand as frequency controlled reserve

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Z.; Togeby, M.; OEstergaard, J.

    2008-09-15

    Using demand as frequency controlled reserve (DFR) is an emerging technology which allow demand to participate actively in maintaining the system operation without reducing the energy service delivered to the customer and without need of user interaction. The basic premise is that traditional frequency controlled reserves from power plants and interconnections with neighbouring systems can be costly, slow and not fulfil the need for future power grids with a high share of wind power and fewer central power plants, and an intention to perform flexible operation such as is landing. Electricity demands, on the other hand, have advantages as frequency reserve including fast activation speed, smooth linear activation, low expected costs, and well-dispersed in the distribution grid. The main challenge of DFR is new methods for monitoring the available capacity. This project has investigated the technology of using electricity demands for providing frequency reserve to power systems. Within the project the potential and economy of DFR compatible loads in Denmark has been investigated, control logic has been designed, power system impact has been investigated, potential business models has been evaluated and an implementation strategy has been suggested. The tasks and goals of the project have been successfully accomplished based on which the conclusion and future recommendation are made. This project has developed the DFR technology that enables electricity demands to autonomously disconnect or reconnect to the grid in response to system frequency variations. The developed DFR technology is proved to be a promising technology from several perspectives. Technically, using DFR is feasible to provide reserves and enhance power system frequency control, while fulfilling technical requirements such as linear activation (or reconnection) according to frequency (or time). Environmentally, the DFR technology is pollution free in contrast to traditional reserves from generation

  7. Resource Demand Scenarios for the Major Metals.

    Science.gov (United States)

    Elshkaki, Ayman; Graedel, T E; Ciacci, Luca; Reck, Barbara K

    2018-03-06

    The growth in metal use in the past few decades raises concern that supplies may be insufficient to meet demands in the future. From the perspective of historical and current use data for seven major metals-iron, manganese, aluminum, copper, nickel, zinc, and lead-we have generated several scenarios of potential metal demand from 2010 to 2050 under alternative patterns of global development. We have also compared those demands with various assessments of potential supply to midcentury. Five conclusions emerge: (1) The calculated demand for each of the seven metals doubles or triples relative to 2010 levels by midcentury; (2) The largest demand increases relate to a scenario in which increasingly equitable values and institutions prevail throughout the world; (3) The metal recycling flows in the scenarios meet only a modest fraction of future metals demand for the next few decades; (4) In the case of copper, zinc, and perhaps lead, supply may be unlikely to meet demand by about midcentury under the current use patterns of the respective metals; (5) Increased rates of demand for metals imply substantial new energy provisioning, leading to increases in overall global energy demand of 21-37%. These results imply that extensive technological transformations and governmental initiatives could be needed over the next several decades in order that regional and global development and associated metal demand are not to be constrained by limited metal supply.

  8. Innovation and Demand

    DEFF Research Database (Denmark)

    Andersen, Esben Sloth

    2007-01-01

    the demand-side of markets in the simplest possible way. This strategy has allowed a gradual increase in the sophistication of supply-side aspects of economic evolution, but the one-sided focus on supply is facing diminishing returns. Therefore, demand-side aspects of economic evolution have in recent years...... received increased attention. The present paper argues that the new emphasis on demand-side factors is quite crucial for a deepened understanding of economic evolution. The major reasons are the following: First, demand represents the core force of selection that gives direction to the evolutionary process....... Second, firms' innovative activities relate, directly or indirectly, to the structure of expected and actual demand. Third, the demand side represents the most obvious way of turning to the much-needed analysis of macro-evolutionary change of the economic system....

  9. PERFECT DEMAND ILLUSION

    Directory of Open Access Journals (Sweden)

    Alexander Yu. Sulimov

    2015-01-01

    Full Text Available The article is devoted to technique «Perfect demand illusion», which allows to strengthen the competitive advantageof retailers. Also in the paper spells out the golden rules of visual merchandising.The definition of the method «Demand illusion», formulated the conditions of its functioning, and is determined by the mainhypothesis of the existence of this method.Furthermore, given the definition of the «Perfect demand illusion», and describes its additional conditions. Also spells out the advantages of the «Perfect demandillusion», before the «Demand illusion».

  10. Divers of Passenger Demand

    OpenAIRE

    Wittmer, Andreas

    2011-01-01

    -Overview drivers of passenger demand -Driver 1: Economic growth in developing countries -Driver 2: International business travel in developed countries -Driver 3: International leisure travel in developed countries

  11. Stroop proactive control and task conflict are modulated by concurrent working memory load.

    Science.gov (United States)

    Kalanthroff, Eyal; Avnit, Amir; Henik, Avishai; Davelaar, Eddy J; Usher, Marius

    2015-06-01

    Performance on the Stroop task reflects two types of conflict-informational (between the incongruent word and font color) and task (between the contextually relevant color-naming task and the irrelevant, but automatic, word-reading task). According to the dual mechanisms of control theory (DMC; Braver, 2012), variability in Stroop performance can result from variability in the deployment of a proactive task-demand control mechanism. Previous research has shown that when proactive control (PC) is diminished, both increased Stroop interference and a reversed Stroop facilitation (RF) are observed. Although the current DMC model accounts for the former effect, it does not predict the observed RF, which is considered to be behavioral evidence for task conflict in the Stroop task. Here we expanded the DMC model to account for Stroop RF. Assuming that a concurrent working memory (WM) task reduces PC, we predicted both increased interference and an RF. Nineteen participants performed a standard Stroop task combined with a concurrent n-back task, which was aimed at reducing available WM resources, and thus overloading PC. Although the results indicated common Stroop interference and facilitation in the low-load condition (zero-back), in the high-load condition (two-back), both increased Stroop interference and RF were observed, consistent with the model's prediction. These findings indicate that PC is modulated by concurrent WM load and serves as a common control mechanism for both informational and task Stroop conflicts.

  12. The Effects of Varying Planning Demands on Drawing Components of Squares and Diamonds.

    Science.gov (United States)

    Broderick, Pia; Laszlo, Judith I.

    1988-01-01

    Investigated effects of changing the level of motor planning demands in simple drawing tasks for which children aged 5-11 years completed or copied squares and diamonds. Results were consistent with previous studies. Low planning demands resulted in less difference between square and diamond performance than did tasks demanding higher planning.…

  13. Current Status and Recommendations for the Future of Research, Teaching, and Testing in the Biological Sciences of Radiation Oncology: Report of the American Society for Radiation Oncology Cancer Biology/Radiation Biology Task Force, Executive Summary

    Energy Technology Data Exchange (ETDEWEB)

    Wallner, Paul E., E-mail: pwallner@theabr.org [21st Century Oncology, LLC, and the American Board of Radiology, Bethesda, Maryland (United States); Anscher, Mitchell S. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States); Barker, Christopher A. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Bassetti, Michael [Department of Human Oncology, University of Wisconsin Carbone Cancer Center, Madison, Wisconsin (United States); Bristow, Robert G. [Departments of Radiation Oncology and Medical Biophysics, Princess Margaret Cancer Center/University of Toronto, Toronto, Ontario (Canada); Cha, Yong I. [Department of Radiation Oncology, Norton Cancer Center, Louisville, Kentucky (United States); Dicker, Adam P. [Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania (United States); Formenti, Silvia C. [Department of Radiation Oncology, New York University, New York, New York (United States); Graves, Edward E. [Departments of Radiation Oncology and Radiology, Stanford University, Stanford, California (United States); Hahn, Stephen M. [Department of Radiation Oncology, University of Pennsylvania (United States); Hei, Tom K. [Center for Radiation Research, Columbia University, New York, New York (United States); Kimmelman, Alec C. [Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Kirsch, David G. [Department of Radiation Oncology, Duke University, Durham, North Carolina (United States); Kozak, Kevin R. [Department of Human Oncology, University of Wisconsin (United States); Lawrence, Theodore S. [Department of Radiation Oncology, University of Michigan (United States); Marples, Brian [Department of Radiation Oncology, Oakland University, Oakland, California (United States); and others

    2014-01-01

    In early 2011, a dialogue was initiated within the Board of Directors (BOD) of the American Society for Radiation Oncology (ASTRO) regarding the future of the basic sciences of the specialty, primarily focused on the current state and potential future direction of basic research within radiation oncology. After consideration of the complexity of the issues involved and the precise nature of the undertaking, in August 2011, the BOD empanelled a Cancer Biology/Radiation Biology Task Force (TF). The TF was charged with developing an accurate snapshot of the current state of basic (preclinical) research in radiation oncology from the perspective of relevance to the modern clinical practice of radiation oncology as well as the education of our trainees and attending physicians in the biological sciences. The TF was further charged with making suggestions as to critical areas of biological basic research investigation that might be most likely to maintain and build further the scientific foundation and vitality of radiation oncology as an independent and vibrant medical specialty. It was not within the scope of service of the TF to consider the quality of ongoing research efforts within the broader radiation oncology space, to presume to consider their future potential, or to discourage in any way the investigators committed to areas of interest other than those targeted. The TF charge specifically precluded consideration of research issues related to technology, physics, or clinical investigations. This document represents an Executive Summary of the Task Force report.

  14. Job-Demands, Job Control, Social Support, Self-Efficacy, and Burnout of Staff of Residential Children's Homes

    Science.gov (United States)

    Brouwers, André; Tomic, Welko

    2016-01-01

    The aim of the current study was to examine among educational staff members of residential children's homes to what extent task demands, job control, emotional and social support from colleagues and management as well as self-efficacy beliefs concerning coping with aggressive behaviour in youngsters are associated with emotional exhaustion,…

  15. Optimal Advertising with Stochastic Demand

    OpenAIRE

    George E. Monahan

    1983-01-01

    A stochastic, sequential model is developed to determine optimal advertising expenditures as a function of product maturity and past advertising. Random demand for the product depends upon an aggregate measure of current and past advertising called "goodwill," and the position of the product in its life cycle measured by sales-to-date. Conditions on the parameters of the model are established that insure that it is optimal to advertise less as the product matures. Additional characteristics o...

  16. Uranium supply and demand

    Energy Technology Data Exchange (ETDEWEB)

    Spriggs, M J

    1976-01-01

    Papers were presented on the pattern of uranium production in South Africa; Australian uranium--will it ever become available; North American uranium resources, policies, prospects, and pricing; economic and political environment of the uranium mining industry; alternative sources of uranium supply; whither North American demand for uranium; and uranium demand and security of supply--a consumer's point of view. (LK)

  17. Wood supply and demand

    Science.gov (United States)

    Peter J. Ince; David B. McKeever

    2011-01-01

    At times in history, there have been concerns that demand for wood (timber) would be greater than the ability to supply it, but that concern has recently dissipated. The wood supply and demand situation has changed because of market transitions, economic downturns, and continued forest growth. This article provides a concise overview of this change as it relates to the...

  18. Spacecraft Demand Tasking and Skip Entry Responsive Maneuvers

    Science.gov (United States)

    2011-06-01

    geomagnetic -induced variations in density and temperature arising due to the solar cycle and related space weather phenomena. As a result, the...perfectly elastic…the tangential velocity is constant and the normal velocity is reversed ,” whereas diffuse collusions are composed of air molecules...Th_first_vec3(:,2) ) set(gca,’XDir’,’ reverse ’) legend(’\\itL/D\\rm =1.0’,’\\itL/D\\rm =1.5’,’\\itL/D\\rm =2.0’,’Location’,’Southwest’); title(’Minimum

  19. The Effect of Visualisation on a Cognitively Demanding Task

    OpenAIRE

    Mahzoon, Alireza

    2015-01-01

    Nowadays, it is more common to see simple interfaces rather than working with the interfaces which look complex. The problem that most students and experts face with when evaluating an interface is mixing up the meaning of usability and complexity. The point is that some of these complex interfaces fulfill the requirements for the definition of usability, ISO 9241 (Bevan, 2001) and usefulness (Nielsen, 2012). In the experiments in what follows, visualization might help the subjects to have a ...

  20. Cognitive task demands modulate the sensitivity of the human cochlea

    Directory of Open Access Journals (Sweden)

    David W Smith

    2012-02-01

    Full Text Available Recent studies lead to the conclusion that focused attention, through the activity of corticofugal and medial olivocochlear efferent pathways, modulates activity at the most peripheral aspects of the auditory system within the cochlea. In two experiments we investigated the effects of different intermodal attention manipulations on the response of outer hair cells (OHCs, and the control exerted by the medial olivocochlear (MOC efferent system. The effect of the MOCs on OHC activity was characterized by measuring the amplitude and rapid adaptation time course of distortion product otoacoustic emissions (DPOAEs. In the first, DPOAE recordings were compared while participants were reading a book and counting the occurrence of the letter a (auditory ignoring and while counting the either short- or long-duration eliciting tones (auditory attending. In the second, DPOAEs were recorded while subjects watched muted movies with subtitles (auditory ignoring/visual distraction and were compared with DPOAEs recorded while subjects counted the same tones (auditory attending as in experiment 1. In both experiments 1 and 2, the absolute level of the averaged DPOAEs recorded during the auditory-ignoring condition was statistically higher than that recorded in the auditory-attending condition. Efferent-induced rapid adaptation was evident in all DPOAE contours, under all attention conditions, suggesting that two medial efferent processes act independently to determine rapid adaptation, which is unaffected by attention, and the overall DPOAE level, which is significantly affected by changes in the focus of attention.

  1. Planning and task management in Parkinson's disease: differential emphasis in dual-task performance.

    Science.gov (United States)

    Bialystok, Ellen; Craik, Fergus I M; Stefurak, Taresa

    2008-03-01

    Seventeen patients diagnosed with Parkinson's disease completed a complex computer-based task that involved planning and management while also performing an attention-demanding secondary task. The tasks were performed concurrently, but it was necessary to switch from one to the other. Performance was compared to a group of healthy age-matched control participants and a group of young participants. Parkinson's patients performed better than the age-matched controls on almost all measures and as well as the young controls in many cases. However, the Parkinson's patients achieved this by paying relatively less attention to the secondary task and focusing attention more on the primary task. Thus, Parkinson's patients can apparently improve their performance on some aspects of a multidimensional task by simplifying task demands. This benefit may occur as a consequence of their inflexible exaggerated attention to some aspects of a complex task to the relative neglect of other aspects.

  2. Asian oil demand

    International Nuclear Information System (INIS)

    Fesharaki, F.

    2005-01-01

    This conference presentation examined global oil market development and the role of Asian demand. It discussed plateau change versus cyclical movement in the global oil market; supply and demand issues of OPEC and non-OPEC oil; if high oil prices reduce demand; and the Asian oil picture in the global context. Asian oil demand has accounted for about 50 per cent of the global incremental oil market growth. The presentation provided data charts in graphical format on global and Asia-Pacific incremental oil demand from 1990-2005; Asia oil demand growth for selected nations; real GDP growth in selected Asian countries; and, Asia-Pacific oil production and net import requirements. It also included charts in petroleum product demand for Asia-Pacific, China, India, Japan, and South Korea. Other data charts included key indicators for China's petroleum sector; China crude production and net oil import requirements; China's imports and the share of the Middle East; China's oil exports and imports; China's crude imports by source for 2004; China's imports of main oil products for 2004; India's refining capacity; India's product balance for net-imports and net-exports; and India's trade pattern of oil products. tabs., figs

  3. Uranium supply and demand

    International Nuclear Information System (INIS)

    1984-05-01

    This report covers the period 1983 to 1995. It draws together the industry's latest views on future trends in supply and demand, and sets them in their historical context. It devotes less discussion than its predecessors to the technical influences underpinning the Institute's supply and demand forecasts, and more to the factors which influence the market behaviour of the industry's various participants. As the last decade has clearly shown, these latter influences can easily be overlooked when undue attention is given to physical imbalances between supply and demand. (author)

  4. On energy demand

    International Nuclear Information System (INIS)

    Haefele, W.

    1977-01-01

    Since the energy crisis, a number of energy plans have been proposed, and almost all of these envisage some kind of energy demand adaptations or conservation measures, hoping thus to escape the anticipated problems of energy supply. However, there seems to be no clear explanation of the basis on which our foreseeable future energy problems could be eased. And in fact, a first attempt at a more exact definition of energy demand and its interaction with other objectives, such as economic ones, shows that it is a highly complex concept which we still hardly understand. The article explains in some detail why it is so difficult to understand energy demand

  5. Linking meters and markets: Roles and incentives to support a flexible demand side

    DEFF Research Database (Denmark)

    Katz, Jonas

    2014-01-01

    wholesale market participants to the demand side is mostly infeasible, resulting in flexibility tasks being aggregated and delegated to balancing responsible wholesale traders. This analysis focuses on whether current incentives and roles are appropriate and where the design could be improved to establish......Present trends in the development of electricity systems are expected to generate a growing need for flexibility in decentralised resources, including demand response. In order to enable decentralised actors to create value, the organisation of markets and incentives should incorporate these new...... a flexible demand side with a particular focus on the Danish case. Design-related barriers are identified that affect expected value, associated risks, and the distribution of responsibilities. This serves as a basis to define policy options in the context of Nordic electricity markets. © 2014 Elsevier Ltd...

  6. Sizewell: UK power demand

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    The Sizewell Inquiry was about whether the next power stations to be built in the UK should be nuclear or coal and, if nuclear, PWRs or AGRs. During the period of the Inquiry forecasts of demand for electricity were low. Now, however, it seems that the forecast demand is much increased. This uncertainty in demand and the wide regional variations are examined in some detail. Facts and figures on electricity sales (area by area) are presented. Also the minutes of supply lost per consumer per year. These show that security of supply is also a problem. It is also shown that the way electricity is used has changed. Whilst electricity generation has been changing to large-scale, centralised power stations the demand patterns may make smaller scale, quickly-constructed units more sensible. The questions considered at the Sizewell Inquiry may, indeed, no longer be the right ones. (UK)

  7. Current status SPEEDI operation and its tasks

    International Nuclear Information System (INIS)

    Fukuyama, Shigeru

    1994-01-01

    The System for Prediction of Environmental Emergency Dose Information called 'SPEEDI' provides realistic estimate of radiation concentration and dose assessment that may result from an atmospheric release of radioactive materials. SPEEDI uses advanced computer-based data processing and data communication system for atmospheric dispersion calculation to derive radiation consequence assessment with the concerned meteorological data and the source term information. SPEEDI has been developed since 1980 by Japan Atomic Energy Research Institute(JAERI), Meteorological Research Institute following to the lessons learned from the accident in 1979 at Three Mile Island, USA. Nuclear Safety Technology Center(NUSTEC) has been constructing a nationwide data communication network that links STA and relevant local governments since 1986. The network now comprises 13 local stations in local governments while the Science and Technology Agency(STA) functions as the command center for SPEEDI in case of emergency. In Japan, the conventional simplified Gaussian plume model has been used for emergency radiation dose estimation however, SPEEDI was recognized as the authorized method for it in 'Emergency Environmental Radiation Monitoring Criteria' and 'Off-site Emergency Planning and Preparedness for Nuclear Power Plants' in 1992. The role of SPEEDI is now far the more important. Local governments are now conducting nuclear emergency exercises almost every year incorporating the information of SPEEDI in their scenarios. (author)

  8. A demanding market

    International Nuclear Information System (INIS)

    Thomas, M.

    1997-01-01

    The article relates to the oil and natural gas market, and it gives a survey of proved reserves at the end of 1996 worldwide. The long term trend of increasing world energy demand has seen a major rise during 1996 when global consumption grew by 3%. But worldwide demand, excluding the Former Soviet Union, shows this figure increasing further to 3.7% for the whole of last year according to statistics. 3 figs

  9. THE TASK TYPE EFFECT ON THE USE OF COMMUNICATION STRATEGIES

    Directory of Open Access Journals (Sweden)

    Elvir Shtavica

    2018-03-01

    Full Text Available An argument that many foreign language students encounter oral communication problems while they try to express their meaning to their partners has encouraged a number of eminent scholars to analyze the use of communication strategies based on the type of the task activity and the level of proficiency. In this paper, the task type effect and the students’ proficiency levels on the communication strategies employed by Kosovan and Bosnian speakers of English were investigated. The purpose of the study was to determine if the students’ proficiency levels and the task type influenced the choice and the number of communication strategies at lexical degree in verbal communication. The study numbered 20 participants in total; Kosovan and Bosnian languages that use English as a foreign language. The subjects were selected upon their degree of proficiency (i.e. Elementary and Intermediate levels and were asked to carry out three different types of the tasks: ten minutes of oral communication, picture story narration and photographic description. The data of the assigned tasks came from audio and video-recording. Thus, the current study used the taxonomy of communication strategies employed by Tarone (1977. Likewise, the communication strategies used by both levels of the students were observed and compared in special instances. It was summarized that the task type and the level of proficiency influenced the number and the choice of different communication strategies in verbal performances. To indicate the present observable facts, two main aspects of the nature of the given tasks were pointed out: context in the task and task demands, respectively.

  10. Student reflections on learning with challenging tasks: `I think the worksheets were just for practice, and the challenges were for maths'

    Science.gov (United States)

    Russo, James; Hopkins, Sarah

    2017-09-01

    The current study considered young students' (7 and 8 years old) experiences and perceptions of mathematics lessons involving challenging (i.e. cognitively demanding) tasks. We used the Constant Comparative Method to analyse the interview responses ( n = 73) regarding what work artefacts students were most proud of creating and why. Five themes emerged that characterised student reflections: enjoyment, effort, learning, productivity and meaningful mathematics. Overall, there was evidence that students embraced struggle and persisted when engaged in mathematics lessons involving challenging tasks and, moreover, that many students enjoyed the process of being challenged. In the second section of the paper, the lesson structure preferences of a subset of participants ( n = 23) when learning with challenging tasks are considered. Overall, more students preferred the teach-first lesson structure to the task-first lesson structure, primarily because it activated their cognition to prepare them for work on the challenging task. However, a substantial minority of students (42 %) instead endorsed the task-first lesson structure, with several students explaining they preferred this structure precisely because it was so cognitively demanding. Other reasons for preferring the task-first structure included that it allowed the focus of the lesson to be on the challenging task and the subsequent discussion of student work. A key implication of these combined findings is that, for many students, work on challenging tasks appeared to remain cognitively demanding irrespective of the structure of the lesson.

  11. 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.

  12. Examining depletion theories under conditions of within-task transfer.

    Science.gov (United States)

    Brewer, Gene A; Lau, Kevin K H; Wingert, Kimberly M; Ball, B Hunter; Blais, Chris

    2017-07-01

    In everyday life, mental fatigue can be detrimental across many domains including driving, learning, and working. Given the importance of understanding and accounting for the deleterious effects of mental fatigue on behavior, a growing body of literature has studied the role of motivational and executive control processes in mental fatigue. In typical laboratory paradigms, participants complete a task that places demand on these self-control processes and are later given a subsequent task. Generally speaking, decrements to subsequent task performance are taken as evidence that the initial task created mental fatigue through the continued engagement of motivational and executive functions. Several models have been developed to account for negative transfer resulting from this "ego depletion." In the current study, we provide a brief literature review, specify current theoretical approaches to ego-depletion, and report an empirical test of current models of depletion. Across 4 experiments we found minimal evidence for executive control depletion along with strong evidence for motivation mediated ego depletion. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  13. Attentional demands and postural recovery: the effects of aging.

    Science.gov (United States)

    Brown, L A; Shumway-Cook, A; Woollacott, M H

    1999-04-01

    Cognitive demands associated with balance and locomotion may contribute to the incidence of falling among older adults. This study addressed issues related to the effects of aging on the attentional demands of recovering from an external disturbance to balance. This research also investigated whether performing a secondary cognitive task differentially affects postural recovery in young versus older adults. Fifteen young and 10 healthy older adults were exposed to a series of balance disturbances. Attentional demands were assessed using a dual task paradigm where postural recovery served as the primary task, and counting backwards served as a concurrent secondary cognitive task. The effect of the counting task was assessed by comparing kinematic variables related to feet-in-place and stepping recovery strategies. Recovering upright stance was found to be attentionally demanding in both age groups. The type of recovery strategy did not influence attentional demands in young adults; however, a hierarchy of increasing attentional demands between the ankle strategy and compensatory stepping was apparent among older adults. In addition, stepping appears to be more attentionally demanding for older adults than for younger adults. Counting backwards did not affect the type of strategy used; however, it did affect the kinematics of stepping. For both age groups, steps occurred when the center of mass was located in a more central location within the base of support when the secondary task was added. The ability to recover a stable posture following an external perturbation is more attentionally demanding for older adults than for younger adults. This would suggest that for some older adults, an increased risk for loss of balance and falls may result if sufficient attentional resources are not allocated to the task of postural recovery.

  14. The Workforce Task Force report: clinical implications for neurology.

    Science.gov (United States)

    Freeman, William D; Vatz, Kenneth A; Griggs, Robert C; Pedley, Timothy

    2013-07-30

    The American Academy of Neurology Workforce Task Force (WFTF) report predicts a future shortfall of neurologists in the United States. The WFTF data also suggest that for most states, the current demand for neurologist services already exceeds the supply, and by 2025 the demand for neurologists will be even higher. This future demand is fueled by the aging of the US population, the higher health care utilization rates of neurologic services, and by a greater number of patients gaining access to the health care system due to the Patient Protection and Affordable Care Act. Uncertainties in health care delivery and patient access exist due to looming concerns about further Medicare reimbursement cuts. This uncertainty is set against a backdrop of Congressional volatility on a variety of issues, including the repeal of the sustainable growth rate for physician reimbursement. The impact of these US health care changes on the neurology workforce, future increasing demands, reimbursement, and alternative health care delivery models including accountable care organizations, nonphysician providers such as nurse practitioners and physician assistants, and teleneurology for both stroke and general neurology are discussed. The data lead to the conclusion that neurologists will need to play an even larger role in caring for the aging US population by 2025. We propose solutions to increase the availability of neurologic services in the future and provide other ways of meeting the anticipated increased demand for neurologic care.

  15. Control and Interference in Task Switching--A Review

    Science.gov (United States)

    Kiesel, Andrea; Steinhauser, Marco; Wendt, Mike; Falkenstein, Michael; Jost, Kerstin; Philipp, Andrea M.; Koch, Iring

    2010-01-01

    The task-switching paradigm offers enormous possibilities to study cognitive control as well as task interference. The current review provides an overview of recent research on both topics. First, we review different experimental approaches to task switching, such as comparing mixed-task blocks with single-task blocks, predictable task-switching…

  16. Global energy demand outlook

    International Nuclear Information System (INIS)

    Hatcher, S.R.

    1999-01-01

    Perhaps the most compelling issue the world will face in the next century is the quality of life of the increasing populations of the poorer regions of the world. Energy is the key to generating wealth and protecting the environment. Today, most of the energy generated comes from fossil fuels and there should be enough for an increase in consumption over the next half century. However, this is likely to be impacted by the Kyoto Protocol on carbon dioxide emissions. Various authoritative studies lead to a global energy demand projection of between 850 to 1070 EJ per year in the mid-21 st century, which is nearly three times as much as the world uses today. The studies further indicate that, unless there is a major thrust by governments to create incentives and/or to levy heavy taxes, the use of fossil fuels will continue to increase and there will be a major increase in carbon dioxide emissions globally. Most of the increase will come from the newly industrializing countries which do not have the technology or financial resources to install non-carbon energy sources such as nuclear power, and the new renewable energy technologies. The real issue for the nuclear industry is investment cost. Developing countries, in particular will have difficulty in raising capital for energy projects with a high installed cost and will have difficulties in raising large blocks of capital. A reduction in investment costs of the order of 50% with a short construction schedule is in order if nuclear power is to compete and contribute significantly to energy supply and the reduction of carbon dioxide emissions. Current nuclear power plants and methods are simply not suited to the production of plants that will compete in this situation. Mass production designs are needed to get the benefits of cost reduction. Water cooled reactors are well demonstrated and positioned to achieve the cost reduction necessary but only via some radical thinking on the part of the designers. The reactors of

  17. Uranium 2009 resources, production and demand

    CERN Document Server

    Organisation for Economic Cooperation and Development. Paris

    2010-01-01

    With several countries currently building nuclear power plants and planning the construction of more to meet long-term increases in electricity demand, uranium resources, production and demand remain topics of notable interest. In response to the projected growth in demand for uranium and declining inventories, the uranium industry – the first critical link in the fuel supply chain for nuclear reactors – is boosting production and developing plans for further increases in the near future. Strong market conditions will, however, be necessary to trigger the investments required to meet projected demand. The "Red Book", jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, is a recognised world reference on uranium. It is based on information compiled in 40 countries, including those that are major producers and consumers of uranium. This 23rd edition provides a comprehensive review of world uranium supply and demand as of 1 January 2009, as well as data on global ur...

  18. Categorization Is Modulated by Transcranial Direct Current Stimulation over Left Prefrontal Cortex

    Science.gov (United States)

    Lupyan, Gary; Mirman, Daniel; Hamilton, Roy; Thompson-Schill, Sharon L.

    2012-01-01

    Humans have an unparalleled ability to represent objects as members of multiple categories. A given object, such as a pillow may be--depending on current task demands--represented as an instance of something that is soft, as something that contains feathers, as something that is found in bedrooms, or something that is larger than a toaster. This…

  19. Competing while cooperating with the same others: The consequences of conflicting demands in co-opetition.

    Science.gov (United States)

    Landkammer, Florian; Sassenberg, Kai

    2016-12-01

    Numerous studies comparing the effects of competition and cooperation demonstrated that competition is detrimental on the social level. However, instead of purely competing, many social contexts require competing while cooperating with the same social target. The current work examined the consequences of such "co-opetition" situations between individuals. Because having to compete and to cooperate with the same social target constitutes conflicting demands, co-opetition should lead to more flexibility, such as (a) less rigid transfer effects of competitive behavior and (b) less rigidity/more flexibility in general. Supporting these predictions, Studies 1a and 1b demonstrated that co-opetition did not elicit competitive behavior in a subsequent task (here: enhanced deceiving of uninvolved others). Study 2 showed that adding conflicting demands (independent of social interdependence) to competition likewise elicits less competitive transfer than competition without such conflicting demands. Beyond that, co-opetition reduced rigid response tendencies during a classification task in Studies 3a and 3b and enhanced flexibility during brainstorming in Study 4, compared with other forms of interdependence. Together, these results suggest that co-opetition leads to more flexible behavior when individuals have to reconcile conflicting demands. Implications for research on social priming, interdependence and competition in everyday life are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  20. UK Nuclear Workforce Demand

    International Nuclear Information System (INIS)

    Roberts, John

    2017-01-01

    UK Nuclear Sites: DECOMMISSIONING - 26 Magnox Reactors, 2 Fast Reactors; OPERATIONAL - 14 AGRs, 1 PWR; 9.6 GWe Total Capacity. Nuclear Workforce Demand • Total workforce demand is expected to grow from ~88,000 in 2017 to ~101,000 in 2021 • Average “inflow” is ~7,000 FTEs per annum • 22% of the workforce is female (28% in civil, 12% in defence) • 81% generic skills, 18% nuclear skills, 1% subject matter experts • 3300 trainees total in SLCs and Defence Enterprise (16% graduate trainees) • At peak demand on Civils Construction, over 4,000 workers will be required on each nuclear new build site • Manufacturing workforce is expected to rise from around 4,000 in 2014 to 8,500 at the peak of onsite activity in 2025

  1. Growing energy demand - environmental impact

    International Nuclear Information System (INIS)

    Rama Rao, G.A.

    2012-01-01

    Scientists can bring information, insights, and analytical skills to bear on matters of public concern. Often they can help the public and its representatives to understand the likely causes of events (such as natural and technological disasters) and to estimate the possible effects of projected policies. Often they can testify to what is not possible. Even so, scientists can seldom bring definitive answers to matters of public debate. Some issues are too complex to fit within the current scope of science, or there may be little reliable information available, or the values involved may lie outside of science. Scientists and technologists strive to find an answer to the growing energy demand

  2. The approach to engineering tasks composition on knowledge portals

    Science.gov (United States)

    Novogrudska, Rina; Globa, Larysa; Schill, Alexsander; Romaniuk, Ryszard; Wójcik, Waldemar; Karnakova, Gaini; Kalizhanova, Aliya

    2017-08-01

    The paper presents an approach to engineering tasks composition on engineering knowledge portals. The specific features of engineering tasks are highlighted, their analysis makes the basis for partial engineering tasks integration. The formal algebraic system for engineering tasks composition is proposed, allowing to set the context-independent formal structures for engineering tasks elements' description. The method of engineering tasks composition is developed that allows to integrate partial calculation tasks into general calculation tasks on engineering portals, performed on user request demand. The real world scenario «Calculation of the strength for the power components of magnetic systems» is represented, approving the applicability and efficiency of proposed approach.

  3. Demand Modelling in Telecommunications

    Directory of Open Access Journals (Sweden)

    M. Chvalina

    2009-01-01

    Full Text Available This article analyses the existing possibilities for using Standard Statistical Methods and Artificial Intelligence Methods for a short-term forecast and simulation of demand in the field of telecommunications. The most widespread methods are based on Time Series Analysis. Nowadays, approaches based on Artificial Intelligence Methods, including Neural Networks, are booming. Separate approaches will be used in the study of Demand Modelling in Telecommunications, and the results of these models will be compared with actual guaranteed values. Then we will examine the quality of Neural Network models. 

  4. DemandStat

    International Nuclear Information System (INIS)

    2003-01-01

    DemandStat is an accurate and up-to-date international statistics database dedicated to energy demand, with an unrivaled level of details for powerful market analysis. It provides detailed consumption statistics (30 sectors) on all energies, detailed 2003 data and historical annual data since 1970, frequent data revision and update (2 updates options), 150 data sources gathered and expertized, all data on a single database Consistent and homogeneous statistics, in line with all major data providers (IEA, Eurostat, ADB, OLADE, etc), no ruptures in time-series with easy request building and data analysis and reactive support from data experts. (A.L.B.)

  5. Education on Demand

    DEFF Research Database (Denmark)

    Boysen, Lis; Hende, Merete

    2015-01-01

    Dette notat beskriver nogle af resultaterne fra programmet "Education on Demand' i projektet Det erhvervsrettede Uddannelseslaboratorium. Programmet har haft fokus på udfordringer og forandringsbehov i uddannelsesinstitutioner og -systemet. Herunder har det beskæftiget sig særligt med de to temat......Dette notat beskriver nogle af resultaterne fra programmet "Education on Demand' i projektet Det erhvervsrettede Uddannelseslaboratorium. Programmet har haft fokus på udfordringer og forandringsbehov i uddannelsesinstitutioner og -systemet. Herunder har det beskæftiget sig særligt med de...

  6. Demand chain management - The evolution

    Directory of Open Access Journals (Sweden)

    D Ericsson

    2011-06-01

    Full Text Available The concepts of Supply Chain Management (SCM and Demand Chain Management (DCM are among the new and debated topics concerning logistics in the literature. The question considered in this paper is: “Are these concepts needed or will they just add to the confusion?” Lasting business concepts have always evolved in close interaction between business and academia. Different approaches start out in business and they are then, more or less si- multaneously, aligned, integrated, systemised and structured in academia. In this way a terminology (or language is provided that helps in further diffusion of the concepts. There is a lack of consensus on the definition of the concept of SCM. This may be one of the major reasons for the difficulty in advancing the science and measuring the results of implementation in business. Relationships in SCM span from rather loose coalitions to highly structured virtual network integrations. DCM is a highly organised chain in which the key is mutual interdependence and partnership. The purpose is to create a distinctive competence for the chain as a whole that helps to identify and satisfy customer needs and wishes. The classical research concerning vertical marketing systems is very helpful in systemising the rather unstructured discussions in current SCM research. The trend lies in increasing competition between channels rather than between companies, which in turn leads to the creation of channels with a high degree of partnership and mutual interdependence between members. These types of channels are known as organised vertical marketing systems in the classic marketing channel research. The behaviour in these types of channels, as well as the formal and informal structures, roles in the network, power and dependence relations, etc. are well covered topics in the literature. The concept of vertical marketing systems lies behind the definition of demand chains and demand chain management proposed in this paper. A

  7. When demand accelerates demand : Trailing the bandwagon

    NARCIS (Netherlands)

    van Herpen, E.; Pieters, R.; Zeelenberg, M.

    2009-01-01

    Consumers generally prefer scarce products, which has been related to their exclusiveness. Currently scarce products, however, are not necessarily exclusive, but could be scarce because many other consumers previously bought them. We propose that consumers also prefer scarce products in this

  8. When demand accelerates demand: Trailing the bandwagon

    NARCIS (Netherlands)

    Herpen, van E.; Pieters, F.G.M.; Zeelenberg, M.

    2009-01-01

    Consumers generally prefer scarce products, which has been related to their exclusiveness. Currently scarce products, however, are not necessarily exclusive, but could be scarce because many other consumers previously bought them. We propose that consumers also prefer scarce products in this

  9. Household energy demand. Empirical studies concerning Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Dargay, J; Lundin, A

    1978-06-01

    This paper investigates the effects of energy policy on households in Sweden and provides the material necessary for evaluation of current and proposed energy-conservation measures. Emphasis is placed on the impact of enery taxation or price changes on household demand for electricity, heating oil, and gasoline and the consequences of such measures for income distribution. The results of the Swedish studies of household demand for heating oil and gasoline indicate that price changes can have a considerable long run impact on fuel utilization. In the short run, price responsiveness is notably reduced, but it is nevertheless of consequence for energy demand.

  10. Causality in demand

    DEFF Research Database (Denmark)

    Nielsen, Max; Jensen, Frank; Setälä, Jari

    2011-01-01

    to fish demand. On the German market for farmed trout and substitutes, it is found that supply sources, i.e. aquaculture and fishery, are not the only determinant of causality. Storing, tightness of management and aggregation level of integrated markets might also be important. The methodological...

  11. Oil supply and demand

    Energy Technology Data Exchange (ETDEWEB)

    Babusiaux, D

    2004-07-01

    Following the military intervention in Iraq, it is taking longer than expected for Iraqi exports to make a comeback on the market. Demand is sustained by economic growth in China and in the United States. OPEC is modulating production to prevent inventory build-up. Prices have stayed high despite increased production by non-OPEC countries, especially Russia. (author)

  12. Oil supply and demand

    Energy Technology Data Exchange (ETDEWEB)

    Rech, O

    2006-07-01

    The year 2004 saw a change in the oil market paradigm that was confirmed in 2005. Despite a calmer geopolitical context, prices continued to rise vigorously. Driven by world demand, they remain high as a result of the saturation of production and refining capacity. The market is still seeking its new equilibrium. (author)

  13. Oil supply and demand

    International Nuclear Information System (INIS)

    Rech, O.

    2006-01-01

    The year 2004 saw a change in the oil market paradigm that was confirmed in 2005. Despite a calmer geopolitical context, prices continued to rise vigorously. Driven by world demand, they remain high as a result of the saturation of production and refining capacity. The market is still seeking its new equilibrium. (author)

  14. The demand for euros

    NARCIS (Netherlands)

    Arnold, I.J.M.; Roelands, S.

    2010-01-01

    This paper investigates the demand for euros using panel data for 10 euro area countries covering the period from 1999 to 2008. Monetary aggregates are constructed to ensure that money is a national concept by excluding deposits owned by non-residents and including external deposits owned by

  15. Oil supply and demand

    International Nuclear Information System (INIS)

    Babusiaux, D.

    2004-01-01

    Following the military intervention in Iraq, it is taking longer than expected for Iraqi exports to make a comeback on the market. Demand is sustained by economic growth in China and in the United States. OPEC is modulating production to prevent inventory build-up. Prices have stayed high despite increased production by non-OPEC countries, especially Russia. (author)

  16. Oil supply and demand

    International Nuclear Information System (INIS)

    Rech, O.

    2004-01-01

    World oil demand, driven by economic development in China, posted the highest growth rate in 20 years. In a context of geopolitical uncertainty, prices are soaring, encouraged by low inventory and the low availability of residual production capacity. Will 2004 bring a change in the oil market paradigm? (author)

  17. Textbook Factor Demand Curves.

    Science.gov (United States)

    Davis, Joe C.

    1994-01-01

    Maintains that teachers and textbook graphics follow the same basic pattern in illustrating changes in demand curves when product prices increase. Asserts that the use of computer graphics will enable teachers to be more precise in their graphic presentation of price elasticity. (CFR)

  18. Oil supply and demand

    Energy Technology Data Exchange (ETDEWEB)

    Rech, O

    2004-07-01

    World oil demand, driven by economic development in China, posted the highest growth rate in 20 years. In a context of geopolitical uncertainty, prices are soaring, encouraged by low inventory and the low availability of residual production capacity. Will 2004 bring a change in the oil market paradigm? (author)

  19. Electricity demand in Tunisia

    International Nuclear Information System (INIS)

    Gam, Imen; Ben Rejeb, Jaleleddine

    2012-01-01

    This paper examines the global electricity demand in Tunisia as a function of gross domestic product in constant price, the degree of urbanization, the average annual temperature, and the real electricity price per Kwh. This demand will be examined employing annual data over a period spanning almost thirty one years from 1976 to 2006. A long run relationship between the variables under consideration is determined using the Vector Autoregressive Regression. The empirical results suggest that the electricity demand in Tunisia is sensitive to its past value, any changes in gross domestic product and electricity price. The electricity price effects have a negative impact on long-run electricity consumption. However, the gross domestic product and the past value of electricity consumption have a positive effect. Moreover, the causality test reveals a unidirectional relationship between price and electricity consumption. Our empirical findings are effective to policy makers to maintain the electricity consumption in Tunisia by using the appropriate strategy. - Highlights: ► This paper examined the electricity demand in Tunisia in the long-run. ► The empirical analysis revealed that in the long-run the electricity demand is affected by changes in its past value, GDP in constant price and real electricity price. ► There is a unidirectional relationship between price and electricity consumption, that is to say, that the electricity price causes the consumption. ► Those results suggest that a pricing policy can be an effective instrument to rationalize the electricity consumption in Tunisia in the long-run.

  20. The Applicability of Rhythm-Motor Tasks to a New Dual Task Paradigm for Older Adults

    Directory of Open Access Journals (Sweden)

    Soo Ji Kim

    2017-12-01

    Full Text Available Given the interplay between cognitive and motor functions during walking, cognitive demands required during gait have been investigated with regard to dual task performance. Along with the needs to understand how the type of concurrent task while walking affects gait performance, there are calls for diversified dual tasks that can be applied to older adults with varying levels of cognitive decline. Therefore, this study aimed to examine how rhythm-motor tasks affect dual task performance and gait control, compared to a traditional cognitive-motor task. Also, it examined whether rhythm-motor tasks are correlated with traditional cognitive-motor task performance and cognitive measures. Eighteen older adults without cognitive impairment participated in this study. Each participant was instructed to walk at self-paced tempo without performing a concurrent task (single walking task and walk while separately performing two types of concurrent tasks: rhythm-motor and cognitive-motor tasks. Rhythm-motor tasks included instrument playing (WalkIP, matching to rhythmic cueing (WalkRC, and instrument playing while matching to rhythmic cueing (WalkIP+RC. The cognitive-motor task involved counting forward by 3s (WalkCount.f3. In each condition, dual task costs (DTC, a measure for how dual tasks affect gait parameters, were measured in terms of walking speed and stride length. The ratio of stride length to walking speed, a measure for dynamic control of gait, was also examined. The results of this study demonstrated that the task type was found to significantly influence these measures. Rhythm-motor tasks were found to interfere with gait parameters to a lesser extent than the cognitive-motor task (WalkCount.f3. In terms of ratio measures, stride length remained at a similar level, walking speed greatly decreased in the WalkCount.f3 condition. Significant correlations between dual task-related measures during rhythm-motor and cognitive-motor tasks support the

  1. Demand Response Resource Quantification with Detailed Building Energy Models

    Energy Technology Data Exchange (ETDEWEB)

    Hale, Elaine; Horsey, Henry; Merket, Noel; Stoll, Brady; Nag, Ambarish

    2017-04-03

    Demand response is a broad suite of technologies that enables changes in electrical load operations in support of power system reliability and efficiency. Although demand response is not a new concept, there is new appetite for comprehensively evaluating its technical potential in the context of renewable energy integration. The complexity of demand response makes this task difficult -- we present new methods for capturing the heterogeneity of potential responses from buildings, their time-varying nature, and metrics such as thermal comfort that help quantify likely acceptability of specific demand response actions. Computed with an automated software framework, the methods are scalable.

  2. Development and validation of a surgical workload measure: the surgery task load index (SURG-TLX).

    Science.gov (United States)

    Wilson, Mark R; Poolton, Jamie M; Malhotra, Neha; Ngo, Karen; Bright, Elizabeth; Masters, Rich S W

    2011-09-01

    The purpose of the present study was to develop and validate a multidimensional, surgery-specific workload measure (the SURG-TLX), and to determine its utility in providing diagnostic information about the impact of various sources of stress on the perceived demands of trained surgical operators. As a wide range of stressors have been identified for surgeons in the operating room, the current approach of considering stress as a unidimensional construct may not only limit the degree to which underlying mechanisms may be understood but also the degree to which training interventions may be successfully matched to particular sources of stress. The dimensions of the SURG-TLX were based on two current multidimensional workload measures and developed via focus group discussion. The six dimensions were defined as mental demands, physical demands, temporal demands, task complexity, situational stress, and distractions. Thirty novices were trained on the Fundamentals of Laparoscopic Surgery (FLS) peg transfer task and then completed the task under various conditions designed to manipulate the degree and source of stress experienced: task novelty, physical fatigue, time pressure, evaluation apprehension, multitasking, and distraction. The results were supportive of the discriminant sensitivity of the SURG-TLX to different sources of stress. The sub-factors loaded on the relevant stressors as hypothesized, although the evaluation pressure manipulation was not strong enough to cause a significant rise in situational stress. The present study provides support for the validity of the SURG-TLX instrument and also highlights the importance of considering how different stressors may load surgeons. Implications for categorizing the difficulty of certain procedures, the implementation of new technology in the operating room (man-machine interface issues), and the targeting of stress training strategies to the sources of demand are discussed. Modifications to the scale to enhance

  3. Compromised Motor Dexterity Confounds Processing Speed Task Outcomes in Stroke Patients

    Directory of Open Access Journals (Sweden)

    Essie Low

    2017-09-01

    Full Text Available Most conventional measures of information processing speed require motor responses to facilitate performance. However, although not often addressed clinically, motor impairment, whether due to age or acquired brain injury, would be expected to confound the outcome measure of such tasks. The current study recruited 29 patients (20 stroke and 9 transient ischemic attack with documented reduction in dexterity of the dominant hand, and 29 controls, to investigate the extent to which 3 commonly used processing speed measures with varying motor demands (a Visuo-Motor Reaction Time task, and the Wechsler Adult Intelligence Scale-IV Symbol Search and Coding subtests may be measuring motor-related speed more so than cognitive speed. Analyses include correlations between indices of cognitive and motor speed obtained from two other tasks (Inspection Time and Pegboard task, respectively with the three speed measures, followed by hierarchical regressions to determine the relative contribution of cognitive and motor speed indices toward task performance. Results revealed that speed outcomes on tasks with relatively high motor demands, such as Coding, were largely reflecting motor speed in individuals with reduced dominant hand dexterity. Thus, findings indicate the importance of employing measures with minimal motor requirements, especially when the assessment of speed is aimed at understanding cognitive rather than physical function.

  4. Aggregated Demand Modelling Including Distributed Generation, Storage and Demand Response

    OpenAIRE

    Marzooghi, Hesamoddin; Hill, David J.; Verbic, Gregor

    2014-01-01

    It is anticipated that penetration of renewable energy sources (RESs) in power systems will increase further in the next decades mainly due to environmental issues. In the long term of several decades, which we refer to in terms of the future grid (FG), balancing between supply and demand will become dependent on demand actions including demand response (DR) and energy storage. So far, FG feasibility studies have not considered these new demand-side developments for modelling future demand. I...

  5. Application of a COTS Resource Optimization Framework to the SSN Sensor Tasking Domain - Part I: Problem Definition

    Science.gov (United States)

    Tran, T.

    With the onset of the SmallSat era, the RSO catalog is expected to see continuing growth in the near future. This presents a significant challenge to the current sensor tasking of the SSN. The Air Force is in need of a sensor tasking system that is robust, efficient, scalable, and able to respond in real-time to interruptive events that can change the tracking requirements of the RSOs. Furthermore, the system must be capable of using processed data from heterogeneous sensors to improve tasking efficiency. The SSN sensor tasking can be regarded as an economic problem of supply and demand: the amount of tracking data needed by each RSO represents the demand side while the SSN sensor tasking represents the supply side. As the number of RSOs to be tracked grows, demand exceeds supply. The decision-maker is faced with the problem of how to allocate resources in the most efficient manner. Braxton recently developed a framework called Multi-Objective Resource Optimization using Genetic Algorithm (MOROUGA) as one of its modern COTS software products. This optimization framework took advantage of the maturing technology of evolutionary computation in the last 15 years. This framework was applied successfully to address the resource allocation of an AFSCN-like problem. In any resource allocation problem, there are five key elements: (1) the resource pool, (2) the tasks using the resources, (3) a set of constraints on the tasks and the resources, (4) the objective functions to be optimized, and (5) the demand levied on the resources. In this paper we explain in detail how the design features of this optimization framework are directly applicable to address the SSN sensor tasking domain. We also discuss our validation effort as well as present the result of the AFSCN resource allocation domain using a prototype based on this optimization framework.

  6. Sulphur demand growing. [Alberta

    Energy Technology Data Exchange (ETDEWEB)

    1975-01-20

    Sulfur markets look better going into 1975 than they have for several years, as North American demand growth is being filled largely by elemental sulfur producers and overseas. Demand is rising as fast as the capacity of Canadian transportation and handling facilities. It will take a long time to make much of a dent in the total Alberta stockpile of 14 million long tons at the end of 1974, with involuntary production from sour gas plants exceeding sales volume since 1972. However, there is some encouragement in the approaching peakout of production combined with a substantial increase in price since the low point of the cycle at the beginning of 1973, and a predicted rise of at least 20% in domestic (North American) sales this year over 1974.

  7. Ontario demand response scenarios

    International Nuclear Information System (INIS)

    Rowlands, I.H.

    2005-09-01

    Strategies for demand management in Ontario were examined via 2 scenarios for a commercial/institutional building with a normal summertime peak load of 300 kW between 14:00 and 18:00 during a period of high electricity demand and high electricity prices. The first scenario involved the deployment of a 150 kW on-site generator fuelled by either diesel or natural gas. The second scenario involved curtailing load by 60 kW during the same periods. Costs and benefits of both scenarios were evaluated for 3 groups: consumers, system operators and society. Benefits included electricity cost savings, deferred transmission capacity development, lower system prices for electricity, as well as environmental changes, economic development, and a greater sense of corporate social responsibility. It was noted that while significant benefits were observed for all 3 groups, they were not substantial enough to encourage action, as the savings arising from deferred generation capacity development do not accrue to individual players. The largest potential benefit was identified as lower prices, spread across all users of electricity in Ontario. It was recommended that representative bodies cooperate so that the system-wide benefits can be reaped. It was noted that if 10 municipal utilities were able to have 250 commercial or institutional customers engaged in distributed response, then a total peak demand reduction of 375 MW could be achieved, representing more than 25 per cent of Ontario's target for energy conservation. It was concluded that demand response often involves the investment of capital and new on-site procedures, which may affect reactions to various incentives. 78 refs., 10 tabs., 5 figs

  8. Household electricity demand profiles

    DEFF Research Database (Denmark)

    Marszal, Anna Joanna; Heiselberg, Per Kvols; Larsen, Olena Kalyanova

    2016-01-01

    Highlights •A 1-min resolution household electricity load model is presented. •Model adapts a bottom-up approach with single appliance as the main building block. •Load profiles are used to analyse the flexibility potential of household appliances. •Load profiles can be applied in other domains, .......g. building energy simulations. •The demand level of houses with different number of occupants is well captured....

  9. Energy demand patterns

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, L; Schipper, L; Meyers, S; Sathaye, J; Hara, Y

    1984-05-01

    This report brings together three papers on energy demand presented at the Energy Research Priorities Seminar held in Ottawa on 8-10 August 1983. The first paper suggests a framework in which energy demand studies may be organized if they are to be useful in policy-making. Disaggregation and the analysis of the chain of energy transformations are possible paths toward more stable and reliable parameters. The second paper points to another factor that leads to instability in sectoral parameters, namely a changeover from one technology to another; insofar as technologies producing a product (or service) vary in their energy intensity, a technological shift will also change the energy intensity of the product. Rapid technological change is characteristic of some sectors in developing countries, and may well account for the high aggregate GDP-elasticities of energy consumption observed. The third paper begins with estimates of these elasticities, which were greater than one for all the member countries of the Asian Development Bank in 1961-78. The high elasticities, together with extreme oil dependence, made them vulnerable to the drastic rise in the oil price after 1973. The author distinguishes three diverging patterns of national experience. The oil-surplus countries naturally gained from the rise in the oil price. Among oil-deficit countries, the newly industrialized countries expanded their exports so rapidly that the oil crisis no longer worried them. For the rest, balance of payments adjustments became a prime concern of policy. Whether they dealt with the oil bill by borrowing, by import substitution, or by demand restraint, the impact of energy on their growth was unmistakable. The paper also shows why energy-demand studies, and energy studies in general, deserve to be taken seriously. 16 refs., 4 figs., 18 tabs.

  10. Migration and Tourism Demand

    Directory of Open Access Journals (Sweden)

    Nuno Carlos LEITÃO

    2012-02-01

    Full Text Available This study considers the relationship between immigration and Portuguese tourism demand for the period 1995-2008, using a dynamic panel data approach. The findings indicate that Portuguese tourism increased significantly during the period in accordance with the values expected for a developed country. The regression results show that income, shock of immigration, population, and geographical distance between Portugal and countries of origin are the main determinants of Portuguese tourism.

  11. Supply and demand perspectives

    International Nuclear Information System (INIS)

    Trienekens, Pieter

    1999-01-01

    The outlook for the European gas market is one of steady growth. This growth will manifest itself in all regions and in all sectors of the market, but most strongly in the power generating sector. To meet future demand, it is necessary to bring gas to Western Europe from remote sources in Russia, North Africa and Norway. These new gas supplies require heavy investments in production and transportation, which can only be undertaken on the basis of long-term take-or-pay contracts. Famous examples of such contracts are the development of the Troll field, the Yamal-Europe pipeline connection, and the bringing on stream of Nigerian LNG for Europe. Tensions are likely to arise between the nature of these long-term gas contracts and the dynamic nature of demand in the gas market, and more specifically in the main growth market, the power sector. The presentation further elaborates on the tensions underlying supply and demand in the years to come

  12. LPG world supply and demand

    International Nuclear Information System (INIS)

    Holmes, Ch.

    2008-01-01

    Over the course of this decade, the global LPG market has moved from being tight, where supply barely exceeded non-price sensitive demand, to the current market situation where supply growth has outstripped demand growth to such an extent that current fundamentals suggest that considerable length will prevail in the market over the near term. As is the case for many other energy commodity markets, the LPG industry has experienced a considerable transformation over the last five years with many new LPG supply projects coming on-stream and demand growth in many developing markets slowing in response to higher energy prices. The near term challenge for LPG producers will be securing outlets for output as the market becomes increasingly oversupplied. With expanding LPG supply and a worldwide tightness in the naphtha market, it is expected that petrochemical consumers will favor relatively low priced LPG over naphtha and the resulting increase in LPG cracking rates will go some way to reducing the expected supply surplus. However, the timing of several new LPG supply projects and the start-up of LPG-based petrochemical plants in the Middle-East are expected to impact global LPG trade and pricing over the next few years. Thus, at this point in time, the global LPG market has a high degree of uncertainty with questions remaining over the impact of high energy (and LPG) prices on traditional and developing market demand, the timing of new supply projects and the combined effect of these two factors on international LPG prices. World LPG production has been rising in nearly every region of the world over the last few years and totaled about 229 million tons in 2007, which is some 30 million tons per year higher than in 2000. The exception is North America which accounts for the largest share of global LPG supply at about 24% but production there has remained relatively flat in recent years. Strong LPG production growth in the Middle-East which contributed to about 19% of

  13. Time-sharing visual and auditory tracking tasks

    Science.gov (United States)

    Tsang, Pamela S.; Vidulich, Michael A.

    1987-01-01

    An experiment is described which examined the benefits of distributing the input demands of two tracking tasks as a function of task integrality. Visual and auditory compensatory tracking tasks were utilized. Results indicate that presenting the two tracking signals in two input modalities did not improve time-sharing efficiency. This was attributed to the difficulty insensitivity phenomenon.

  14. Avoiding the conflict: Metacognitive awareness drives the selection of low-demand contexts.

    Science.gov (United States)

    Desender, Kobe; Buc Calderon, Cristian; Van Opstal, Filip; Van den Bussche, Eva

    2017-07-01

    Previous research attempted to explain how humans strategically adapt behavior in order to achieve successful task performance. Recently, it has been suggested that 1 potential strategy is to avoid tasks that are too demanding. Here, we report 3 experiments that investigate the empirically neglected role of metacognitive awareness in this process. In these experiments, participants could freely choose between performing a task in either a high-demand or a low-demand context. Using subliminal priming, we ensured that participants were not aware of the visual stimuli creating these different demand contexts. Our results showed that participants who noticed a difference in task difficulty (i.e., metacognitive aware participants) developed a clear preference for the low-demand context. In contrast, participants who experienced no difference in task difficulty (i.e., metacognitive unaware participants) based their choices on variables unrelated to cognitive demand (e.g., the color or location associated with a context), and did not develop a preference for the low-demand context. Crucially, this pattern was found despite identical task performance in both metacognitive awareness groups. A multiple regression approach confirmed that metacognitive awareness was the main factor driving the preference for low-demand contexts. These results argue for an important role of metacognitive awareness in the strategic avoidance of demanding tasks. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  15. Modelling curves of manufacturing feasibilities and demand

    Directory of Open Access Journals (Sweden)

    Soloninko K.S.

    2017-03-01

    Full Text Available The authors research the issue of functional properties of curves of manufacturing feasibilities and demand. Settlement of the problem, and its connection with important scientific and practical tasks. According to its nature, the market economy is unstable and is in constant movement. Economy has an effective instrument for explanation of changes in economic environment; this tool is called the modelling of economic processes. The modelling of economic processes depends first and foremost on the building of economic model which is the base for the formalization of economic process, that is, the building of mathematical model. The effective means for formalization of economic process is the creation of the model of hypothetic or imaginary economy. The building of demand model is significant for the market of goods and services. The problem includes the receiving (as the result of modelling definite functional properties of curves of manufacturing feasibilities and demand according to which one can determine their mathematical model. Another problem lies in obtaining majorant properties of curves of joint demand on the market of goods and services. Analysis of the latest researches and publications. Many domestic and foreign scientists dedicated their studies to the researches and building of the models of curves of manufacturing feasibilities and demand. In spite of considerable work of the scientists, such problems as functional properties of the curves and their practical use in modelling. The purpose of the article is to describe functional properties of curves of manufacturing feasibilities and demand on the market of goods and services on the base of modelling of their building. Scientific novelty and practical value. The theoretical regulations (for functional properties of curves of manufacturing feasibilities and demand received as a result of the present research, that is convexity, give extra practical possibilities in a microeconomic

  16. Performing a secondary executive task with affective stimuli interferes with decision making under risk conditions.

    Science.gov (United States)

    Gathmann, Bettina; Pawlikowski, Mirko; Schöler, Tobias; Brand, Matthias

    2014-05-01

    Previous studies demonstrated that executive functions are crucial for advantageous decision making under risk and that therefore decision making is disrupted when working memory capacity is demanded while working on a decision task. While some studies also showed that emotions can affect decision making under risk, it is unclear how affective processing and executive functions predict decision-making performance in interaction. The current experimental study used a between-subjects design to examine whether affective pictures (positive and negative pictures compared to neutral pictures), included in a parallel executive task (working memory 2-back task), have an impact on decision making under risk as assessed by the Game of Dice Task (GDT). Moreover, the performance GDT plus 2-back task was compared to the performance in the GDT without any additional task (GDT solely). The results show that the performance in the GDT differed between groups (positive, negative, neutral, and GDT solely). The groups with affective pictures, especially those with positive pictures in the 2-back task, showed more disadvantageous decisions in the GDT than the groups with neutral pictures and the group performing the GDT without any additional task. However, executive functions moderated the effect of the affective pictures. Regardless of affective influence, subjects with good executive functions performed advantageously in the GDT. These findings support the assumption that executive functions and emotional processing interact in predicting decision making under risk.

  17. Motor demand-dependent activation of ipsilateral motor cortex.

    Science.gov (United States)

    Buetefisch, Cathrin M; Revill, Kate Pirog; Shuster, Linda; Hines, Benjamin; Parsons, Michael

    2014-08-15

    The role of ipsilateral primary motor cortex (M1) in hand motor control during complex task performance remains controversial. Bilateral M1 activation is inconsistently observed in functional (f)MRI studies of unilateral hand performance. Two factors limit the interpretation of these data. As the motor tasks differ qualitatively in these studies, it is conceivable that M1 contributions differ with the demand on skillfulness. Second, most studies lack the verification of a strictly unilateral execution of the motor task during the acquisition of imaging data. Here, we use fMRI to determine whether ipsilateral M1 activity depends on the demand for precision in a pointing task where precision varied quantitatively while movement trajectories remained equal. Thirteen healthy participants used an MRI-compatible joystick to point to targets of four different sizes in a block design. A clustered acquisition technique allowed simultaneous fMRI/EMG data collection and confirmed that movements were strictly unilateral. Accuracy of performance increased with target size. Overall, the pointing task revealed activation in contralateral and ipsilateral M1, extending into contralateral somatosensory and parietal areas. Target size-dependent activation differences were found in ipsilateral M1 extending into the temporal/parietal junction, where activation increased with increasing demand on accuracy. The results suggest that ipsilateral M1 is active during the execution of a unilateral motor task and that its activity is modulated by the demand on precision. Copyright © 2014 the American Physiological Society.

  18. The energy demand in the Narino Department

    International Nuclear Information System (INIS)

    Unidad de Planeacion Minero Energetica, UPME

    2000-01-01

    In the object of making a first approach of regional energy requirements analysis and the good way of satisfying them, the UPME undertook a global energy study for the Narino Department. In this study (UPME 1999) was carried out an analysis of the energy demand and of the socioeconomic factors that determine it; they were also studied the consumptions and the current energy offer and the alternatives of future evolution, with the purpose of having the basic tools of a departmental energy plan. The present article refers specifically to the analysis of the demand and it seeks to show the readers the complexity and the volume of necessary information to carry out the demand studies. They are multiple factors that determine the energy demand in the Narino Department. The size, growth populations, geographical distribution and cultural characteristic, the border condition, the faulty infrastructure of communications, the agricultural economic structure and the low entrance per capita

  19. ACR-SNM Task Force on Nuclear Medicine Training: report of the task force.

    Science.gov (United States)

    Guiberteau, Milton J; Graham, Michael M

    2011-06-01

    The expansion of knowledge and technological advances in nuclear medicine and radiology require physicians to have more expertise in functional and anatomic imaging. The convergence of these two specialties into the new discipline of molecular imaging has also begun to place demands on residency training programs for additional instruction in physiology and molecular biology. These changes have unmasked weaknesses in current nuclear medicine and radiology training programs. Adding to the impetus for change are the attendant realities of the job market and uncertain employment prospects for physicians trained in nuclear medicine but not also trained in diagnostic radiology. With this background, the ACR and the Society of Nuclear Medicine convened the Task Force on Nuclear Medicine Training to define the issues and develop recommendations for resident training.

  20. Cognitive Resource Demands of Redirected Walking.

    Science.gov (United States)

    Bruder, Gerd; Lubas, Paul; Steinicke, Frank

    2015-04-01

    Redirected walking allows users to walk through a large-scale immersive virtual environment (IVE) while physically remaining in a reasonably small workspace. Therefore, manipulations are applied to virtual camera motions so that the user's self-motion in the virtual world differs from movements in the real world. Previous work found that the human perceptual system tolerates a certain amount of inconsistency between proprioceptive, vestibular and visual sensation in IVEs, and even compensates for slight discrepancies with recalibrated motor commands. Experiments showed that users are not able to detect an inconsistency if their physical path is bent with a radius of at least 22 meters during virtual straightforward movements. If redirected walking is applied in a smaller workspace, manipulations become noticeable, but users are still able to move through a potentially infinitely large virtual world by walking. For this semi-natural form of locomotion, the question arises if such manipulations impose cognitive demands on the user, which may compete with other tasks in IVEs for finite cognitive resources. In this article we present an experiment in which we analyze the mutual influence between redirected walking and verbal as well as spatial working memory tasks using a dual-tasking method. The results show an influence of redirected walking on verbal as well as spatial working memory tasks, and we also found an effect of cognitive tasks on walking behavior. We discuss the implications and provide guidelines for using redirected walking in virtual reality laboratories.

  1. Ethane supply and demand

    International Nuclear Information System (INIS)

    Jamerson, J.B.

    1993-01-01

    Estimates are given for ethane production, chiefly from the Gulf Coast area. Increase in interregional transfers are predicted. Comparisons from 1992 through 1995 are made. The author concludes the following: ethane will be supply limited over the decade of the 90's; values will be over competing feedstocks; minimum practical demands will be close to available supply; regional relationships will reflect pipeline tariffs; purity ethane/EP spreads may narrow with new Mt. Belvieu fractionation capacity; new domestic supplies will back out imports; and Ethane's share of ethylene production may drop over the period

  2. Management of Water Demand in Africa and the Middle East ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Management of Water Demand in Africa and the Middle East : Current Practices and Future Needs. Couverture du livre Management of Water Demand in Africa and the Middle East : Current Practices. Directeur(s) : David B. Brooks, Eglal Rached et Maurice Saade. Maison(s) d'édition : CRDI. 1 janvier 1997. ISBN : Épuisé.

  3. Management of Water Demand in Africa and the Middle East ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    1997-01-01

    Management of Water Demand in Africa and the Middle East : Current Practices and Future Needs. Couverture du livre Management of Water Demand in Africa and the Middle East : Current Practices. Editor(s):. David B. Brooks, Eglal Rached et Maurice Saade. Publisher(s):. CRDI. January 1, 1997. ISBN: Épuisé. 78 pages.

  4. Demand Response Valuation Frameworks Paper

    Energy Technology Data Exchange (ETDEWEB)

    Heffner, Grayson

    2009-02-01

    While there is general agreement that demand response (DR) is a valued component in a utility resource plan, there is a lack of consensus regarding how to value DR. Establishing the value of DR is a prerequisite to determining how much and what types of DR should be implemented, to which customers DR should be targeted, and a key determinant that drives the development of economically viable DR consumer technology. Most approaches for quantifying the value of DR focus on changes in utility system revenue requirements based on resource plans with and without DR. This ''utility centric'' approach does not assign any value to DR impacts that lower energy and capacity prices, improve reliability, lower system and network operating costs, produce better air quality, and provide improved customer choice and control. Proper valuation of these benefits requires a different basis for monetization. The review concludes that no single methodology today adequately captures the wide range of benefits and value potentially attributed to DR. To provide a more comprehensive valuation approach, current methods such as the Standard Practice Method (SPM) will most likely have to be supplemented with one or more alternative benefit-valuation approaches. This report provides an updated perspective on the DR valuation framework. It includes an introduction and four chapters that address the key elements of demand response valuation, a comprehensive literature review, and specific research recommendations.

  5. Road infrastructure and demand induction

    DEFF Research Database (Denmark)

    Nielsen, Thomas Alexander Sick; Hovgesen, Henrik Harder; Lahrmann, Harry

    2006-01-01

    a long screenline is used to measure the development in aggregate demand in selected corridors. The paper analyses demand induction by establishing time series of aggregate demand that is compared with the national traffic index. Significant trend breaks in the association between aggregate demand...... in the corridors and the national index, following the opening of motorways or bridges, indicates demand induction by infrastructure expansion in a number of instances. Lack of significant trend breaks following opening year is found in peripheral areas where major population centres are missing. This indicates...... the necessity of some latent demand within suitable travel range for new infrastructure elements to produce significant amounts of induced demand. Estimates of demand induction as a percentage of the realised demand five years after opening are between 10% and 67% for new motorway sections depending...

  6. Tobacco demand, delay discounting, and smoking topography among smokers with and without psychopathology.

    Science.gov (United States)

    Farris, Samantha G; Aston, Elizabeth R; Abrantes, Ana M; Zvolensky, Michael J

    2017-10-01

    Tobacco demand (i.e., relative value attributed to a given reinforcer) and delay discounting (i.e., relative preference for smaller immediate rewards over larger delayed rewards) are two behavioral economic processes that are linked to the progression of problematic substance use. These processes have not been studied among those with psychopathology, a vulnerable group of smokers. The current study examined differences in tobacco demand and delay discounting, and their association with smoking topography among smokers with (n=43) and without (n=64) past-year psychopathology. Adult daily smokers (n=107,M age =43.5; SD=9.7) participated in a study on "smoking behavior." Past-year psychological disorders were assessed via a clinician-administered diagnostic assessment. All subjects participated in an ad libitum smoking trial and then completed an assessment of delay discounting (Monetary Choice Questionnaire) and tobacco demand (Cigarette Purchase Task) approximately 45-60min post-smoking. Smokers with psychopathology, compared to those without, had significantly higher demand intensity and maximum expenditure on tobacco (O max ), but did not differ on other demand indices or delay discounting. Smokers with psychopathology had shorter average inter-puff intervals and shorter time to cigarette completion than smokers without psychopathology. Tobacco demand and delay discounting measures were significantly intercorrelated among smokers with psychopathology, but not those without. Both behavioral economic measures were associated with specific aspects of smoking topography in smokers with psychopathology. The association between tobacco demand and delay discounting is evident among smokers with psychopathology and both measures were most consistently related to smoking behavior. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Resolving task rule incongruence during task switching by competitor rule suppression.

    Science.gov (United States)

    Meiran, Nachshon; Hsieh, Shulan; Dimov, Eduard

    2010-07-01

    Task switching requires maintaining readiness to execute any task of a given set of tasks. However, when tasks switch, the readiness to execute the now-irrelevant task generates interference, as seen in the task rule incongruence effect. Overcoming such interference requires fine-tuned inhibition that impairs task readiness only minimally. In an experiment involving 2 object classification tasks and 2 location classification tasks, the authors show that irrelevant task rules that generate response conflicts are inhibited. This competitor rule suppression (CRS) is seen in response slowing in subsequent trials, when the competing rules become relevant. CRS is shown to operate on specific rules without affecting similar rules. CRS and backward inhibition, which is another inhibitory phenomenon, produced additive effects on reaction time, suggesting their mutual independence. Implications for current formal theories of task switching as well as for conflict monitoring theories are discussed. (c) 2010 APA, all rights reserved

  8. Demand for electrical energy

    International Nuclear Information System (INIS)

    Bergougnoux, J.; Fouquet, D.

    1983-01-01

    The different utilizations of electric energy are reviewed in the residential and tertiary sectors, in the industry. The competitive position of electricity in regard to other fuels has been strengthned by the sudden rise in the price of oil in 1973-1974 and 1979-1980. The evolution of electricity prices depended on the steps taken to adjust the electricity generation system. The substitution of electricity applications for hydro-carbons is an essential point of energy policy. The adjustment at all times, at least cost and most reliability, of the supply of electricity to the demand for it is a major problem in the design and operation of electric systems. National demand for power at a given moment is extremely diversified. Electricity consumption presents daily and seasonal variations, and variations according to the different sectors. Forecasting power requirements is for any decision on operation or investment relating to an electrical system. Load management is desirable (prices according to the customers, optional tariffs for ''peak-day withdrawal''). To conclude, prospects for increased electricity consumption are discussed [fr

  9. Matching energy sources to demand

    International Nuclear Information System (INIS)

    Hendry, A.

    1979-01-01

    Diagrams show the current pattern of energy usage in Scotland; primary energy inputs; the various classes of user; the disposition of input energy in terms of useful and waste energy; an energy flow diagram showing the proportions of primary fuels taken by the various user groups and the proportions of useful energy derived by each. Within the S.S.E.B. area, installed capacity and maximum demand are shown for the present and projected future to the year 2000. A possible energy flow diagram for Scotland in 1996 is shown. The more efficient use of energy is discussed, with particular reference to the use of electricity. The primary energy inputs considered are oil, coal, nuclear, hydro and gas. (U.K.)

  10. Stress in nonregular work arrangements: A longitudinal study of task- and employment-related aspects of stress.

    Science.gov (United States)

    Vahle-Hinz, Tim

    2016-10-01

    In nonregular forms of employment, such as fixed-term or temporary agency work, 2 sources of stress must be distinguished: task-related stress components (e.g., time pressure) and employment-related stress components (e.g., effort to maintain employment). The present study investigated the relationship between task- and employment-related demands and resources and indicators of strain, well-being, work engagement, and self-rated performance in a sample of nonregular employed workers. Using a 2-wave longitudinal design, the results of autoregressive cross-lagged structural equation models demonstrated that time pressure, as a task-related demand, is positively related to strain and negatively related to well-being and self-rated performance. Autonomy, as a task-related resource, exhibited no significant relationships in the current study. Employment-related demands exhibited negative relationships with well-being and work engagement as well as negative and positive relationships with self-rated performance over time. Employment-related resources were primarily positive predictors of well-being and self-rated performance. Fit indices of comparative models indicated that reciprocal effect models (which enable causal and reverse effects) best fit the data. Accordingly, demands and resources predicted strain, well-being, work engagement, and self-rated performance over time and vice versa. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  11. The Effect of "Massed" Task Repetitions on Complexity, Accuracy and Fluency: Does It Transfer to a New Task?

    Science.gov (United States)

    Ahmadian, Mohammad Javad

    2011-01-01

    To date, research results suggest that task repetition positively affects oral task performance. However, researchers have not yet shown the extension of the benefits of repeating the same task to performance of a new task. This article first provides an overview of the currently available research findings on task repetition and then presents the…

  12. The Curvilinear Relationship between State Neuroticism and Momentary Task Performance

    Science.gov (United States)

    Debusscher, Jonas; Hofmans, Joeri; De Fruyt, Filip

    2014-01-01

    A daily diary and two experience sampling studies were carried out to investigate curvilinearity of the within-person relationship between state neuroticism and task performance, as well as the moderating effects of within-person variation in momentary job demands (i.e., work pressure and task complexity). In one, results showed that under high work pressure, the state neuroticism–task performance relationship was best described by an exponentially decreasing curve, whereas an inverted U-shaped curve was found for tasks low in work pressure, while in another study, a similar trend was visible for task complexity. In the final study, the state neuroticism–momentary task performance relationship was a linear one, and this relationship was moderated by momentary task complexity. Together, results from all three studies showed that it is important to take into account the moderating effects of momentary job demands because within-person variation in job demands affects the way in which state neuroticism relates to momentary levels of task performance. Specifically, we found that experiencing low levels of state neuroticism may be most beneficial in high demanding tasks, whereas more moderate levels of state neuroticism are optimal under low momentary job demands. PMID:25238547

  13. LHCb computing tasks

    CERN Document Server

    Binko, P

    1998-01-01

    This document describes the computing tasks of the LHCb computing system. It also describes the logistics of the dataflow between the tasks and the detailed requirements for each task, in particular the data sizes and CPU power requirements. All data sizes are calculated assuming that the LHCb experiment will take data about 107 s per year at a frequency of 200 Hz, which gives 2 \\Theta 109 real events per year. The raw event size should not exceed 100 kB (200 TB per year). We will have to generate about 109 MonteCarlo events per year. The current MonteCarlo simulation program based on the GEANT3.21 package requires about 12 s to produce an average event (all CPU times are normalised to a 1000 MIPS processor). The size of an average MonteCarlo event will be about 200 kB (100 TB per year) of simulated data (without the hits). We will start to use the GEANT4 package in 1998. Rejection factors of 8 and 25 are required in the Level-2 and Level-3 triggers respectively, to reduce the frequency of events to 200 Hz. T...

  14. Uranium 2009: Resources, Production and Demand

    International Nuclear Information System (INIS)

    2010-01-01

    With several countries currently building nuclear power plants and planning the construction of more to meet long-term increases in electricity demand, uranium resources, production and demand remain topics of notable interest. In response to the projected growth in demand for uranium and declining inventories, the uranium industry - the first critical link in the fuel supply chain for nuclear reactors - is boosting production and developing plans for further increases in the near future. Strong market conditions will, however, be necessary to trigger the investments required to meet projected demand. The 'Red Book', jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, is a recognised world reference on uranium. It is based on information compiled in 40 countries, including those that are major producers and consumers of uranium. This 23. edition provides a comprehensive review of world uranium supply and demand as of 1 January 2009, as well as data on global uranium exploration, resources, production and reactor-related requirements. It provides substantive new information from major uranium production centres around the world, as well as from countries developing production centres for the first time. Projections of nuclear generating capacity and reactor-related uranium requirements through 2035 are also featured, along with an analysis of long-term uranium supply and demand issues

  15. Demand for male contraception.

    Science.gov (United States)

    Dorman, Emily; Bishai, David

    2012-10-01

    The biological basis for male contraception was established decades ago, but despite promising breakthroughs and the financial burden men increasingly bear due to better enforcement of child support policies, no viable alternative to the condom has been brought to market. Men who wish to control their fertility must rely on female compliance with contraceptives, barrier methods, vasectomy or abstinence. Over the last 10 years, the pharmaceutical industry has abandoned most of its investment in the field, leaving only nonprofit organisations and public entities pursuing male contraception. Leading explanations are uncertain forecasts of market demand pitted against the need for critical investments to demonstrate the safety of existing candidate products. This paper explores the developments and challenges in male contraception research. We produce preliminary estimates of potential market size for a safe and effective male contraceptive based on available data to estimate the potential market for a novel male method.

  16. Animating the Ethical Demand

    DEFF Research Database (Denmark)

    Vistisen, Peter; Jensen, Thessa; Poulsen, Søren Bolvig

    2015-01-01

    This paper addresses the challenge of attaining ethical user stances during the design process of products and services and proposes animation-based sketching as a design method, which supports elaborating and examining different ethical stances towards the user. The discussion is qualified...... by an empirical study of Responsible Research and Innovation (RRI) in a Triple Helix constellation. Using a three-week long innovation workshop, U- CrAc, involving 16 Danish companies and organisations and 142 students as empirical data, we discuss how animation-based sketching can explore not yet existing user...... dispositions, as well as create an incentive for ethical conduct in development and innovation processes. The ethical fulcrum evolves around Løgstrup’s Ethical Demand and his notion of spontaneous life manifestations. From this, three ethical stances are developed; apathy, sympathy and empathy. By exploring...

  17. Rewarding yet demanding

    DEFF Research Database (Denmark)

    Bjørkedal, S T B; Torsting, A M B; Møller, T

    2016-01-01

    in a logbook. The Canadian Occupational Performance Measure was used to initiate and guide the intervention and the Canadian Model of Client-Centred Enablement for the client-therapist relationship. RESULTS: Participants described the intervention, which presupposed a certain level of patient readiness...... design comprising an eight-week client-centred occupational therapy intervention with semi-structured interviews with five of the six clients out of 10 who completed the intervention. Braun and Clark's thematic analysis was applied to the transcripts. Adherence rate and dropouts were recorded......, as demanding. Participants valued engaging in real-life occupations while anchoring new strategies but also the occupational therapist's role in dealing with failure. Participants felt the intervention assisted in their recovery process and enabled them to engage in meaningful occupations. CONCLUSION...

  18. PROOF on Demand

    International Nuclear Information System (INIS)

    Malzacher, Peter; Manafov, Anar

    2010-01-01

    PROOF on Demand (PoD) is a set of utilities, which allows starting a PROOF cluster at user request, on any resource management system. It provides a plug-in based system, which allows to use different job submission frontends, such as LSF or gLite WMS. Main components of PoD are the PROOFAgent and the PAConsole. PROOFAgent provides the communication layer between the PROOF master on the local machine and the PROOF workers on the remote resources, possibly behind a firewall. PAConsole provides a user-friendly GUI, which is used to setup, manage, and shutdown the dynamic PROOF cluster. Installation is simple and doesn't require administrator privileges, and all the processes run in user space. PoD gives users, who don't have a centrally-administrated static PROOF cluster at their institute, the possibility to enjoy the full power of interactive analysis with PROOF.

  19. Adapting to Changing Memory Retrieval Demands: Evidence from Event-Related Potentials

    Science.gov (United States)

    Benoit, Roland G.; Werkle-Bergner, Markus; Mecklinger, Axel; Kray, Jutta

    2009-01-01

    This study investigated preparatory processes involved in adapting to changing episodic memory retrieval demands. Event-related potentials (ERPs) were recorded while participants performed a general old/new recognition task and a specific task that also required retrieval of perceptual details. The relevant task remained either constant or changed…

  20. The functional neuroanatomy of multitasking: combining dual tasking with a short term memory task.

    Science.gov (United States)

    Deprez, Sabine; Vandenbulcke, Mathieu; Peeters, Ron; Emsell, Louise; Amant, Frederic; Sunaert, Stefan

    2013-09-01

    Insight into the neural architecture of multitasking is crucial when investigating the pathophysiology of multitasking deficits in clinical populations. Presently, little is known about how the brain combines dual-tasking with a concurrent short-term memory task, despite the relevance of this mental operation in daily life and the frequency of complaints related to this process, in disease. In this study we aimed to examine how the brain responds when a memory task is added to dual-tasking. Thirty-three right-handed healthy volunteers (20 females, mean age 39.9 ± 5.8) were examined with functional brain imaging (fMRI). The paradigm consisted of two cross-modal single tasks (a visual and auditory temporal same-different task with short delay), a dual-task combining both single tasks simultaneously and a multi-task condition, combining the dual-task with an additional short-term memory task (temporal same-different visual task with long delay). Dual-tasking compared to both individual visual and auditory single tasks activated a predominantly right-sided fronto-parietal network and the cerebellum. When adding the additional short-term memory task, a larger and more bilateral frontoparietal network was recruited. We found enhanced activity during multitasking in components of the network that were already involved in dual-tasking, suggesting increased working memory demands, as well as recruitment of multitask-specific components including areas that are likely to be involved in online holding of visual stimuli in short-term memory such as occipito-temporal cortex. These results confirm concurrent neural processing of a visual short-term memory task during dual-tasking and provide evidence for an effective fMRI multitasking paradigm. © 2013 Elsevier Ltd. All rights reserved.

  1. Regional supply, demand and utilization of forest biomass in South-East Finland; Metsaeenergian kaeytoen kasvun liiketoimintamahdollisuudet Kaakkois-Suomessa

    Energy Technology Data Exchange (ETDEWEB)

    Laihanen, M.; Karhunen, A.; Ranta, T.

    2011-07-01

    Rising demand of forest biomass in South-East Finland has created need to evaluate the impact for different energy users and producers. The aim of this study is to settle the current demand and availability of forest biomass and to evaluate the opportunities the growth offers. Initial data of study base on current structure of energy supply and on current energy demand. The information can be used as a guideline when evaluating local sufficiency of energy wood and business opportunities for local actors such as energy producers and forest fuel suppliers. Main aim of the study is to create prosperity and entrepreneurship to South-East Finland. Analysis included following tasks: gathering data about the current and potential use and users of forest biomass (logging residues, stumps and small diameter energy wood), settling local availability of forest fuels, creating forest biomass balance to indicate the sufficiency of local resources and to identify the effects of current business opportunities around forest biomass sector. Results of the study illustrate local balance between use and availability of energy wood, need for labor and revenue of forest biomass supply in South-East Finland. Evaluation analysis constructed for regional and local needs combine the current and potential use of forest biomass with local availability. Analysis represents model for evaluating local possibilities of utilization of forest biomass. Co-operation with Forestry Centre of South-East Finland was productive through entire study. (orig.)

  2. Demand and supply in Russian gas market

    International Nuclear Information System (INIS)

    Milovidov, K.N.

    1997-01-01

    The big volume of gas supplies for current and future energy and natural gas balances in Russia is important to understand the likely future dynamics of demand for gas. The path of future demand in Russia is uncertain and the range of possible scenarios is wide. For creating the new gas consumption structure, more deep diversification and development of the gas distribution systems, large investments and considerable periods of time are necessary. The factors usually studied in detail in the conditions of market economy can not be used here as a basis for strategic planning due to several reasons. (R.P.)

  3. Occupational demand and human rights. Public safety officers and cardiorespiratory fitness.

    Science.gov (United States)

    Shephard, R J

    1991-08-01

    The issue of discrimination in physically demanding employment, such as police, firefighters, prison guards and military personnel, is contentious. In terms of oxygen transport, the 'action limit' (calling for personnel selection or task redesign) is a steady oxygen consumption of 0.7 L/min, while the maximum permissible limit is 2.1 L/min. Note is taken of the commonly expressed belief that public safety duties are physically demanding, calling for personnel with an aerobic power of at least 3 L/min, or 42 to 45 ml/kg/min. The actual demands of such work can be assessed on small samples by physiological measurements (using heart rate or oxygen consumption meters), but the periods sampled may not be typical of a normal day. A Gestalt can also be formed as to the heaviness of a given job, or a detailed task analysis can be performed; most such analyses of public safety work list distance running and other aerobic activities infrequently. An arbitrary requirement of 'above average fitness' is no longer accepted by courts, but a further approach is to examine the characteristics of those currently meeting the demands of public safety jobs satisfactorily. Young men commonly satisfy the 3 L/min standard, but this is not usually the case for women or older men; in the case of female employees, it also seems unreasonable that they should be expected to satisfy the same standards as men, since a lower body mass reduces the energy cost of most of the tasks that they must perform. A second criterion sometimes applied to physically demanding work (a low vulnerability to heart attacks) is examined critically. It is concluded that the chances that a symptom-free public safety officer will develop a heart attack during a critical solo mission are so low that cardiac risk should not be a condition of employment. Arbitrary age- and sex-related employment criteria are plainly discriminatory, since some women and 65-year-old men have higher levels of physical fitness than the

  4. Environment-quality demands

    International Nuclear Information System (INIS)

    Delfini, M.G.; Leenhouts, H.P.

    1988-12-01

    In the framework of the Environment Quality Requirements (MKE) project a model has been designed in which environment-quality demands have been defined and quantified, and a measuring strategy has been developed. In the model it is required for the quality of the environment that the radionuclide concentration in the various environment compartiments remains limited in order to keep the effective dose equivalence for the 'reference man' under a certain reference level. In order to be able to determine the maximum nuclide concentration it is necessary to quantify the relation between the concentration in the environment and the dose for the people. The quantitative relation between concentration and dose has been established on the base of parameters (Derived Activity Limits (DAL's) which have to be calculated for each environment compartiment, each nuclide and each exposure pathway. This model has been described and, as example, the DAL's have been calculated for the compartiment air (for which the two exposure pathways inhalation and direct radiation were considered). For the other environment compartiments a similar elaboration is needed. The feasibility of application of the MKE-model in the actual practice of measurements in the environment and examination of dose for the population depends upon the possibility for performing nuclide specific measurements in all environment compartiments, the level of the dose resulting from the contamination of the environment and the related accurateness of the measurements

  5. Increasing Working Memory Load Reduces Processing of Cross-Modal Task-Irrelevant Stimuli Even after Controlling for Task Difficulty and Executive Capacity.

    Science.gov (United States)

    Simon, Sharon S; Tusch, Erich S; Holcomb, Phillip J; Daffner, Kirk R

    2016-01-01

    The classic account of the load theory (LT) of attention suggests that increasing cognitive load leads to greater processing of task-irrelevant stimuli due to competition for limited executive resource that reduces the ability to actively maintain current processing priorities. Studies testing this hypothesis have yielded widely divergent outcomes. The inconsistent results may, in part, be related to variability in executive capacity (EC) and task difficulty across subjects in different studies. Here, we used a cross-modal paradigm to investigate whether augmented working memory (WM) load leads to increased early distracter processing, and controlled for the potential confounders of EC and task difficulty. Twenty-three young subjects were engaged in a primary visual WM task, under high and low load conditions, while instructed to ignore irrelevant auditory stimuli. Demands of the high load condition were individually titrated to make task difficulty comparable across subjects with differing EC. Event-related potentials (ERPs) were used to measure neural activity in response to stimuli presented in both the task relevant modality (visual) and task-irrelevant modality (auditory). Behavioral results indicate that the load manipulation and titration procedure of the primary visual task were successful. ERPs demonstrated that in response to visual target stimuli, there was a load-related increase in the posterior slow wave, an index of sustained attention and effort. Importantly, under high load, there was a decrease of the auditory N1 in response to distracters, a marker of early auditory processing. These results suggest that increased WM load is associated with enhanced attentional engagement and protection from distraction in a cross-modal setting, even after controlling for task difficulty and EC. Our findings challenge the classic LT and offer support for alternative models.

  6. Increasing working memory load reduces processing of cross-modal task-irrelevant stimuli even after controlling for task difficulty and executive capacity

    Directory of Open Access Journals (Sweden)

    Sharon Sanz Simon

    2016-08-01

    Full Text Available The classic account of the Load Theory (LT of attention suggests that increasing cognitive load leads to greater processing of task-irrelevant stimuli due to competition for limited executive resource that reduces the ability to actively maintain current processing priorities. Studies testing this hypothesis have yielded widely divergent outcomes. The inconsistent results may, in part, be related to variability in executive capacity (EC and task difficulty across subjects in different studies. Here, we used a cross-modal paradigm to investigate whether augmented working memory (WM load leads to increased early distracter processing, and controlled for the potential confounders of EC and task difficulty. Twenty-three young subjects were engaged in a primary visual WM task, under high and low load conditions, while instructed to ignore irrelevant auditory stimuli. Demands of the high load condition were individually titrated to make task difficulty comparable across subjects with differing EC. Event-related potentials (ERPs were used to measure neural activity in response to stimuli presented in both the task relevant modality (visual and task-irrelevant modality (auditory. Behavioral results indicate that the load manipulation and titration procedure of the primary visual task were successful. ERPs demonstrated that in response to visual target stimuli, there was a load-related increase in the posterior slow wave, an index of sustained attention and effort. Importantly, under high load, there was a decrease of the auditory N1 in response to distracters, a marker of early auditory processing. These results suggest that increased WM load is associated with enhanced attentional engagement and protection from distraction in a cross-modal setting, even after controlling for task difficulty and EC. Our findings challenge the classic LT and offer support for alternative models.

  7. Intrinsic motivation and organizational identification among on-demand workers.

    Science.gov (United States)

    Rockmann, Kevin W; Ballinger, Gary A

    2017-09-01

    On-demand firms provide services for clients through a network of on-demand workers ready to complete specific tasks for a set contractual price. Given such on-demand work is defined by payment on short-term contracts with no obligation for continued employment, there is little reason to believe on-demand workers experience more than extrinsic motivation and a transactional relationship with the on-demand firm. However, using self-determination theory, we argue that to the degree that on-demand work fulfills innate psychological needs individual on-demand workers will develop intrinsic motivation, which further leads to organizational identification with the on-demand firm. Across 2 survey-based studies we find support for this path to organizational identification. This adds to the literature on motivation and identification by strengthening the link between individual needs and the individual-organizational relationship. Implications for theory and for the management of on-demand workers are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  8. Ad libitum or demand/semi-demand feeding versus scheduled interval feeding for preterm infants.

    Science.gov (United States)

    McCormick, Felicia M; Tosh, Karen; McGuire, William

    2010-02-17

    Scheduled interval feeding of prescribed enteral volumes is current standard practice for preterm infants. However, feeding preterm infants in response to their hunger and satiation cues (ad libitum or demand/semi demand) rather than at scheduled intervals might help in the establishment of independent oral feeding, increase nutrient intake and growth rates, and allow earlier hospital discharge. To assess the effect of a policy of feeding preterm infants on an ad libitum or demand/semi-demand basis versus feeding prescribed volumes at scheduled intervals on growth rates and the time to hospital discharge. We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2009), MEDLINE (1966 to Oct 2009), EMBASE (1980 to Oct 2009), CINAHL (1982 to Oct 2009), conference proceedings, and previous reviews. Randomised or quasi-randomised controlled trials (including cluster randomised trials) that compared a policy of feeding preterm infants on an ad libitum or demand/semi-demand basis versus feeding at scheduled intervals. We used the standard methods of the Cochrane Neonatal Review Group with separate evaluation of trial quality and data extraction by two review authors. We found eight randomised controlled trials that compared ad libitum or demand/semi-demand regimens with scheduled interval regimes in preterm infants in the transition phase from intragastric tube to oral feeding. The trials were generally small and of variable methodological quality. The duration of the intervention and the duration of data collection and follow-up in most of the trials was not likely to have allowed detection of measurable effects on growth. Three trials reported that feeding preterm infants using an ad libitum or demand/semi-demand feeding regimen allowed earlier discharge from hospital (by about two to four days) but other trials did not confirm this

  9. Algae as a Feedstock for Biofuels. An Assessment of the Current Status and Potential for Algal Biofuels Production. Joint Summary report of IEA-AMF Annex XXXIV-2 and IEA Bioenergy Task 39

    Energy Technology Data Exchange (ETDEWEB)

    O' Conner, D. [S and T2 Consultants, Inc. (Canada)

    2011-09-15

    In 2010, the IEA Advanced Motor Fuels Implementing Agreement and the IEA Bioenergy Task 39 both commissioned reports on the status and potential opportunities for Algal Biofuels. While there were substantial similarities in the findings of the two reports, each report provides unique perspectives on different aspects of the technology and the opportunities. This summary draws on both of those reports. The Task 39 report (Bioenergy Algal Biofuels.pdf) was authored by Al Darzins and Philip Pienkos (NREL, US) and Les Edye (BioIndustry Partners, Australia). The IEA AMF report was prepared by Karen Sikes and Ralph McGill (Sentech, Inc. US) and Martijn Van Walwijk (Independent Researcher).

  10. Coping with unexpected oil demand movements

    International Nuclear Information System (INIS)

    Anon.

    2004-01-01

    Continuous upward revisions to world oil demand projections for 2003 and 2004 are compared with the downward revisions that took place in 1998 and 1999, following the 1997 Asian economic crisis. Demand leads supply, in the current case, resulting in a time-lag in the whole supply chain, while supply led demand half a decade ago, with the OECD's commercial stocks reaching record highs. Recent months have seen a reversal of the longstanding inverse relationship between the United States of America's commercial crude oil stock levels and crude prices, and they are now moving in parallel. The fact that the US market is now adequately or even well supplied means that factors other than inventory levels are causing the present high prices. These factors are briefly outlined. OPEC is doing everything it can to maintain market stability, with prices at levels acceptable to producers and consumers. The agreement reached in Beirut on 3 June is the latest example of this. (Author)

  11. Forecasting Ontario's blood supply and demand.

    Science.gov (United States)

    Drackley, Adam; Newbold, K Bruce; Paez, Antonio; Heddle, Nancy

    2012-02-01

    Given an aging population that requires increased medical care, an increasing number of deferrals from the donor pool, and a growing immigrant population that typically has lower donation rates, the purpose of this article is to forecast Ontario's blood supply and demand. We calculate age- and sex-specific donation and demand rates for blood supply based on 2008 data and project demand between 2008 and 2036 based on these rates and using population data from the Ontario Ministry of Finance. Results indicate that blood demand will outpace supply as early as 2012. For instance, while the total number of donations made by older cohorts is expected to increase in the coming years, the number of red blood cell (RBC) transfusions in the 70+ age group is forecasted grow from approximately 53% of all RBC transfusions in 2008 (209,515) in 2008 to 68% (546,996) by 2036. A series of alternate scenarios, including projections based on a 2% increase in supply per year and increased use of apheresis technology, delays supply shortfalls, but does not eliminate them without active management and/or multiple methods to increase supply and decrease demand. Predictions show that demand for blood products will outpace supply in the near future given current age- and sex-specific supply and demand rates. However, we note that the careful management of the blood supply by Canadian Blood Services, along with new medical techniques and the recruitment of new donors to the system, will remove future concerns. © 2012 American Association of Blood Banks.

  12. Modelling Commodity Demands and Labour Supply with m-Demands

    OpenAIRE

    Browning, Martin

    1999-01-01

    In the empirical modelling of demands and labour supply we often lack data on a full set of goods. The usual response is to invoke separability assumptions. Here we present an alternative based on modelling demands as a function of prices and the quantity of a reference good rather than total expenditure. We term such demands m-demands. The advantage of this approach is that we make maximum use of the data to hand without invoking implausible separability assumptions. In the theory section qu...

  13. Managing demand uncertainty: probabilistic selling versus inventory substitution

    OpenAIRE

    Zhang, Y.; Hua, Guowei; Wang, Shouyang; Zhang, Juliang; Fernández Alarcón, Vicenç

    2018-01-01

    Demand variability is prevailing in the current rapidly changing business environment, which makes it difficult for a retailer that sells multiple substitutable products to determine the optimal inventory. To combat demand uncertainty, both strategies of inventory substitution and probabilistic selling can be used. Although the two strategies differ in operation, we believe that they share a common feature in combating demand uncertainty by encouraging some customers to give up some specific ...

  14. Uranium 1999. Resources, production and demand

    International Nuclear Information System (INIS)

    2000-01-01

    In recent years, the world uranium market has been characterised by an imbalance between demand and supply and persistently depressed uranium prices. World uranium production currently satisfies between 55 and 60 per cent of the total reactor-related requirements, while the rest of the demand is met by secondary sources including the conversion of excess defence material and stockpiles, primarily from Eastern Europe. Although the future availability of these secondary sources remains unclear, projected low-cost production capability is expected to satisfy a considerable part of demand through to 2015. Information in this report provides insights into changes expected in uranium supply and demand over the next 15 years. The 'Red Book', jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, is the foremost world reference on uranium. It is based on official information from 49 countries and includes compilations of statistics on resources, exploration, production and demand as of 1 January 1999. It provides substantial new information from all of the major uranium producing centres in Africa, Australia, Eastern Europe, North America and the New Independent States. It also contains an international expert analysis of industry statistics and world-wide projections of nuclear energy growth, uranium requirements and uranium supply. (authors)

  15. Feeding a fierce demand

    Energy Technology Data Exchange (ETDEWEB)

    Zlontinov, D.

    2008-09-15

    Wolverine is a metallurgical coal mining project located in British Columbia (BC). The Wolverine project is owned by Western, who is currently expanding the project by developing an open pit mine property with a reserve of 18 million tonnes located close to its current mine. The company has purchased several new trucks, front shovel loaders, and blasthole drills, and is now shifting over 65,000 bank cubic meters (BCM) per day. Western is also planning to develop an underground mine in the region. The company has formed contracts and business relationships with several smaller companies in order to allow for more rapid startups of its mining operations. However, the company's expansion has been impeded by shortages in qualified mining personnel. The Wolverine project had been engaged in long-term contracts with the Japanese steel industry. Western has now established a number of relationships with clients in Europe, China, and South Korea. 3 figs.

  16. Cognitive task analysis

    NARCIS (Netherlands)

    Schraagen, J.M.C.

    2000-01-01

    Cognitive task analysis is defined as the extension of traditional task analysis techniques to yield information about the knowledge, thought processes and goal structures that underlie observable task performance. Cognitive task analyses are conducted for a wide variety of purposes, including the

  17. Interhemispheric interaction expands attentional capacity in an auditory selective attention task.

    Science.gov (United States)

    Scalf, Paige E; Banich, Marie T; Erickson, Andrew B

    2009-04-01

    Previous work from our laboratory indicates that interhemispheric interaction (IHI) functionally increases the attentional capacity available to support performance on visual tasks (Banich in The asymmetrical brain, pp 261-302, 2003). Because manipulations of both computational complexity and selection demand alter the benefits of IHI to task performance, we argue that IHI may be a general strategy for meeting increases in attentional demand. Other researchers, however, have suggested that the apparent benefits of IHI to attentional capacity are an epiphenomenon of the organization of the visual system (Fecteau and Enns in Neuropsychologia 43:1412-1428, 2005; Marsolek et al. in Neuropsychologia 40:1983-1999, 2002). In the current experiment, we investigate whether IHI increases attentional capacity outside the visual system by manipulating the selection demands of an auditory temporal pattern-matching task. We find that IHI expands attentional capacity in the auditory system. This suggests that the benefits of requiring IHI derive from a functional increase in attentional capacity rather than the organization of a specific sensory modality.

  18. Gaming is related to enhanced working memory performance and task-related cortical activity.

    Science.gov (United States)

    Moisala, M; Salmela, V; Hietajärvi, L; Carlson, S; Vuontela, V; Lonka, K; Hakkarainen, K; Salmela-Aro, K; Alho, K

    2017-01-15

    Gaming experience has been suggested to lead to performance enhancements in a wide variety of working memory tasks. Previous studies have, however, mostly focused on adult expert gamers and have not included measurements of both behavioral performance and brain activity. In the current study, 167 adolescents and young adults (aged 13-24 years) with different amounts of gaming experience performed an n-back working memory task with vowels, with the sensory modality of the vowel stream switching between audition and vision at random intervals. We studied the relationship between self-reported daily gaming activity, working memory (n-back) task performance and related brain activity measured using functional magnetic resonance imaging (fMRI). The results revealed that the extent of daily gaming activity was related to enhancements in both performance accuracy and speed during the most demanding (2-back) level of the working memory task. This improved working memory performance was accompanied by enhanced recruitment of a fronto-parietal cortical network, especially the dorsolateral prefrontal cortex. In contrast, during the less demanding (1-back) level of the task, gaming was associated with decreased activity in the same cortical regions. Our results suggest that a greater degree of daily gaming experience is associated with better working memory functioning and task difficulty-dependent modulation in fronto-parietal brain activity already in adolescence and even when non-expert gamers are studied. The direction of causality within this association cannot be inferred with certainty due to the correlational nature of the current study. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Data-driven Demand Response Characterization and Quantification

    DEFF Research Database (Denmark)

    Le Ray, Guillaume; Pinson, Pierre; Larsen, Emil Mahler

    2017-01-01

    Analysis of load behavior in demand response (DR) schemes is important to evaluate the performance of participants. Very few real-world experiments have been carried out and quantification and characterization of the response is a difficult task. Nevertheless it will be a necessary tool for portf...

  20. Gaze control during interceptive actions with different spatiotemporal demands.

    NARCIS (Netherlands)

    Navia, J.A.; Dicks, M.S.; van der Kamp, J; Ruiz, L.

    It is widely accepted that the sources of information used to guide interceptive actions depend on conflicting spatiotemporal task demands. However, there is a paucity of evidence that shows how information pick-up during interceptive actions is adapted to such conflicting constraints. The present

  1. Autonomic Nervous System Responses to Hearing-Related Demand and Evaluative Threat.

    Science.gov (United States)

    Mackersie, Carol L; Kearney, Lucia

    2017-10-12

    This paper consists of 2 parts. The purpose of Part 1 was to review the potential influence of internal (person-related) factors on listening effort. The purpose of Part 2 was to present, in support of Part 1, preliminary data illustrating the interactive effects of an external factor (task demand) and an internal factor (evaluative threat) on autonomic nervous system measures. For Part 1, we provided a brief narrative review of motivation and stress as modulators of listening effort. For Part 2, we described preliminary data from a study using a repeated-measures (2 × 2) design involving manipulations of task demand (high, low) and evaluative threat (high, low). The low-demand task consisted of repetition of sentences from a narrative. The high-demand task consisted of answering questions about the narrative, requiring both comprehension and recall. During the high evaluative threat condition, participants were filmed and told that their video recordings would be evaluated by a panel of experts. During the low evaluative threat condition, no filming occurred; participants were instructed to "do your best." Skin conductance (sympathetic nervous system activity) and heart rate variability (HRV, parasympathetic activity) were measured during the listening tasks. The HRV measure was the root mean square of successive differences of adjacent interbeat intervals. Twelve adults with hearing loss participated. Skin conductance increased and HRV decreased relative to baseline (no task) for all listening conditions. Skin conductance increased significantly with an increase in evaluative threat, but only for the more demanding task. There was no significant change in HRV in response to increasing evaluative threat or task demand. Listening effort may be influenced by factors other than task difficulty, as reviewed in Part 1. This idea is supported by the preliminary data indicating that the sympathetic nervous system response to task demand is modulated by social evaluative

  2. Skyrmion production on demand by homogeneous DC currents

    Czech Academy of Sciences Publication Activity Database

    Everschor-Sitte, K.; Sitte, M.; Valet, T.; Abanov, A.; Sinova, Jairo

    2017-01-01

    Roč. 19, Sep (2017), s. 1-5, č. článku 092001. ISSN 1367-2630 R&D Projects: GA ČR GB14-37427G; GA MŠk EF16_013/0001405 EU Projects: European Commission(XE) 610115 - SC2 Grant - others:OP VVV - LNSM(XE) CZ.02.1.01/0.0/0.0/16_013/0001405 Institutional support: RVO:68378271 Keywords : magnetization dynamics * micromagnetic simulations * skyrmions * thin films Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.786, year: 2016

  3. Promotion and Fast Food Demand

    OpenAIRE

    Timothy J. Richards; Luis Padilla

    2009-01-01

    Many believe that fast food promotion is a significant cause of the obesity epidemic in North America. Industry members argue that promotion only reallocates brand shares and does not increase overall demand. We study the effect of fast food promotion on market share and total demand by estimating a discrete / continuous model of fast food restaurant choice and food expenditure that explicitly accounts for both spatial and temporal determinants of demand. Estimates are obtained using a unique...

  4. Intercity Travel Demand Analysis Model

    OpenAIRE

    Ming Lu; Hai Zhu; Xia Luo; Lei Lei

    2014-01-01

    It is well known that intercity travel is an important component of travel demand which belongs to short distance corridor travel. The conventional four-step method is no longer suitable for short distance corridor travel demand analysis for the time spent on urban traffic has a great impact on traveler's main mode choice. To solve this problem, the author studied the existing intercity travel demand analysis model, then improved it based on the study, and finally established a combined model...

  5. Job demands-resources model

    OpenAIRE

    Bakker, Arnold; Demerouti, Eva

    2013-01-01

    markdownabstract* The question of what causes job stress and what motivates people has received a lot of research attention during the past five decades. In this paper, we discuss Job Demands-Resources (JD-R) theory, which represents an extension of the Job Demands-Resources model (Bakker & Demerouti, 2007; Demerouti, Bakker, Nachreiner, & Schaufeli, 2001) and is inspired by job design and job stress theories. JD-R theory explains how job demands and resources have unique and multiplicative e...

  6. Rules and more rules: the effects of multiple tasks, extensive training, and aging on task-switching performance.

    Science.gov (United States)

    Buchler, Norbou G; Hoyer, William J; Cerella, John

    2008-06-01

    Task-switching performance was assessed in young and older adults as a function of the number of task sets to be actively maintained in memory (varied from 1 to 4) over the course of extended training (5 days). Each of the four tasks required the execution of a simple computational algorithm, which was instantaneously cued by the color of the two-digit stimulus. Tasks were presented in pure (task set size 1) and mixed blocks (task set sizes 2, 3, 4), and the task sequence was unpredictable. By considering task switching beyond two tasks, we found evidence for a cognitive control system that is not overwhelmed by task set size load manipulations. Extended training eliminated age effects in task-switching performance, even when the participants had to manage the execution of up to four tasks. The results are discussed in terms of current theories of cognitive control, including task set inertia and production system postulates.

  7. Oil supply and demand

    International Nuclear Information System (INIS)

    Mourez, B.; Favennec, J.P.

    1999-01-01

    During 1998, the price of oil continued to fall. In the autumn of 1997, the barrel of Brent was worth about $20 but then its price dropped to $10 during the last months of 1998. Early in 1997, market-watchers began to think that a downturn was possible, but it occurred on a scale that caught operators by surprise. It is always difficult to predict short- and medium-term prices or, in this case, to determine whether current prices, generally considered to be low, are here to stay

  8. North American oil demand outlook

    International Nuclear Information System (INIS)

    Stewart, M.B.

    1995-01-01

    An understanding of the relationship of economic growth and potential petroleum product demand is needed to forecast the potential for North American oil demand growth as well as knowledge of world supply and price. The bullish expectations for economic growth in the US and Canada auger well for North American refiners and marketeers. The growth in world economic output forecast, however, means a larger oil demand and an increase in OPEC's pricing power. Such price increases could depress North American oil demand growth. (author)

  9. Biology task group

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The accomplishments of the task group studies over the past year are reviewed. The purposes of biological investigations, in the context of subseabed disposal, are: an evaluation of the dose to man; an estimation of effects on the ecosystem; and an estimation of the influence of organisms on and as barriers to radionuclide migration. To accomplish these ends, the task group adopted the following research goals: (1) acquire more data on biological accumulation of specific radionuclides, such as those of Tc, Np, Ra, and Sr; (2) acquire more data on transfer coefficients from sediment to organism; (3) Calculate mass transfer rates, construct simple models using them, and estimate collective dose commitment; (4) Identify specific pathways or transfer routes, determine the rates of transfer, and make dose limit calculations with simple models; (5) Calculate dose rates to and estimate irradiation effects on the biota as a result of waste emplacement, by reference to background irradiation calculations. (6) Examine the effect of the biota on altering sediment/water radionuclide exchange; (7) Consider the biological data required to address different accident scenarios; (8) Continue to provide the basic biological information for all of the above, and ensure that the system analysis model is based on the most realistic and up-to-date concepts of marine biologists; and (9) Ensure by way of free exchange of information that the data used in any model are the best currently available

  10. Demand management concept and tool in a dynamic context

    NARCIS (Netherlands)

    Liu, Ankun

    2008-01-01

    ChainScope B.V. is a startup company that develops supply chain optimization and planning software. The optimization software is currently based on the assumption of stationary demand. However, in real-life situation future demand is forecasted through a combination of time series analysis and human

  11. Using Demand Side Management to Adapt to Water Scarcity and ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    The Saiss is a sub-basin of the Sebou basin in Northern Morocco. Due to decreased precipitation and increased water demand, the surface waters of the Saiss basin have been greatly reduced. At the current rate of exploitation, the aquifer will be depleted within 25 years. This project will examine whether demand-side ...

  12. Task-dependent and distinct roles of the temporoparietal junction and inferior frontal cortex in the control of imitation.

    Science.gov (United States)

    Hogeveen, Jeremy; Obhi, Sukhvinder S; Banissy, Michael J; Santiesteban, Idalmis; Press, Clare; Catmur, Caroline; Bird, Geoffrey

    2015-07-01

    The control of neurological networks supporting social cognition is crucially important for social interaction. In particular, the control of imitation is directly linked to interaction quality, with impairments associated with disorders characterized by social difficulties. Previous work suggests inferior frontal cortex (IFC) and the temporoparietal junction (TPJ) are involved in controlling imitation, but the functional roles of these areas remain unclear. Here, transcranial direct current stimulation (tDCS) was used to enhance cortical excitability at IFC and the TPJ prior to the completion of three tasks: (i) a naturalistic social interaction during which increased imitation is known to improve rapport, (ii) a choice reaction time task in which imitation needs to be inhibited for successful performance and (iii) a non-imitative control task. Relative to sham stimulation, stimulating IFC improved the context-dependent control of imitation-participants imitated more during the social interaction and less during the imitation inhibition task. In contrast, stimulating the TPJ reduced imitation in the inhibition task without affecting imitation during social interaction. Neither stimulation site affected the non-imitative control task. These data support a model in which IFC modulates imitation directly according to task demands, whereas TPJ controls task-appropriate shifts in attention toward representation of the self or the other, indirectly impacting upon imitation. © The Author (2014). Published by Oxford University Press.

  13. The Integron: Adaptation On Demand.

    Science.gov (United States)

    Escudero, José Antonio; Loot, Céline; Nivina, Aleksandra; Mazel, Didier

    2015-04-01

    The integron is a powerful system which, by capturing, stockpiling, and rearranging new functions carried by gene encoding cassettes, confers upon bacteria a rapid adaptation capability in changing environments. Chromosomally located integrons (CI) have been identified in a large number of environmental Gram-negative bacteria. Integron evolutionary history suggests that these sedentary CIs acquired mobility among bacterial species through their association with transposable elements and conjugative plasmids. As a result of massive antibiotic use, these so-called mobile integrons are now widespread in clinically relevant bacteria and are considered to be the principal agent in the emergence and rise of antibiotic multiresistance in Gram-negative bacteria. Cassette rearrangements are catalyzed by the integron integrase, a site-specific tyrosine recombinase. Central to these reactions is the single-stranded DNA nature of one of the recombination partners, the attC site. This makes the integron a unique recombination system. This review describes the current knowledge on this atypical recombination mechanism, its implications in the reactions involving the different types of sites, attC and attI, and focuses on the tight regulation exerted by the host on integron activity through the control of attC site folding. Furthermore, cassette and integrase expression are also highly controlled by host regulatory networks and the bacterial stress (SOS) response. These intimate connections to the host make the integron a genetically stable and efficient system, granting the bacteria a low cost, highly adaptive evolution potential "on demand".

  14. BATMAN: MOS Spectroscopy on Demand

    Science.gov (United States)

    Molinari, E.; Zamkotsian, F.; Moschetti, M.; Spano, P.; Boschin, W.; Cosentino, R.; Ghedina, A.; González, M.; Pérez, H.; Lanzoni, P.; Ramarijaona, H.; Riva, M.; Zerbi, F.; Nicastro, L.; Valenziano, L.; Di Marcantonio, P.; Coretti, I.; Cirami, R.

    2016-10-01

    Multi-Object Spectrographs (MOS) are the major instruments for studying primary galaxies and remote and faint objects. Current object selection systems are limited and/or difficult to implement in next generation MOS for space and ground-based telescopes. A promising solution is the use of MOEMS devices such as micromirror arrays, which allow the remote control of the multi-slit configuration in real time. TNG is hosting a novelty project for real-time, on-demand MOS masks based on MOEMS programmable slits. We are developing a 2048×1080 Digital-Micromirror-Device-based (DMD) MOS instrument to be mounted on the Galileo telescope, called BATMAN. It is a two-arm instrument designed for providing in parallel imaging and spectroscopic capabilities. With a field of view of 6.8×3.6 arcmin and a plate scale of 0.2 arcsec per micromirror, this astronomical setup can be used to investigate the formation and evolution of galaxies. The wavelength range is in the visible and the spectral resolution is R=560 for a 1 arcsec object, and the two arms will have 2k × 4k CCD detectors. ROBIN, a BATMAN demonstrator, has been designed, realized and integrated. We plan to have BATMAN first light by mid-2016.

  15. Selection of maintenance tasks

    Energy Technology Data Exchange (ETDEWEB)

    Dean, B; Rombos, P [Wardrop (W.L.) and Associates Ltd., Winnipeg, MB (Canada)

    1995-10-01

    Two methodologies for maintenance task selection, Reliability Centre Maintenance (RCM) and Degradation Mode Analysis (DMA), are compared with regard to application in the nuclear industry and potential for application at CANDU nuclear power plants. RCM is the favoured one of the two methodologies. It is more thorough than DMA, is well supported within the US nuclear industry, and - with experience in application - is gaining cost effectiveness. There is interest in the use of RCM in other nations, including France and Japan, and it is already being implemented at Bruce A NGS and Bruce B NGS in Canada. DMA lags behind RCM in development and currently there is little experience to support claims of major benefits at reduced cost. Significant advantages over RCM need to be demonstrated if DMA is to gain acceptance in the nuclear industry. (author). 41 refs., 7 tabs., 8 figs.

  16. Selection of maintenance tasks

    International Nuclear Information System (INIS)

    Dean, B.; Rombos, P.

    1995-10-01

    Two methodologies for maintenance task selection, Reliability Centre Maintenance (RCM) and Degradation Mode Analysis (DMA), are compared with regard to application in the nuclear industry and potential for application at CANDU nuclear power plants. RCM is the favoured one of the two methodologies. It is more thorough than DMA, is well supported within the US nuclear industry, and - with experience in application - is gaining cost effectiveness. There is interest in the use of RCM in other nations, including France and Japan, and it is already being implemented at Bruce A NGS and Bruce B NGS in Canada. DMA lags behind RCM in development and currently there is little experience to support claims of major benefits at reduced cost. Significant advantages over RCM need to be demonstrated if DMA is to gain acceptance in the nuclear industry. (author). 41 refs., 7 tabs., 8 figs

  17. Do job demands and job control affect problem-solving?

    Science.gov (United States)

    Bergman, Peter N; Ahlberg, Gunnel; Johansson, Gun; Stoetzer, Ulrich; Aborg, Carl; Hallsten, Lennart; Lundberg, Ingvar

    2012-01-01

    The Job Demand Control model presents combinations of working conditions that may facilitate learning, the active learning hypothesis, or have detrimental effects on health, the strain hypothesis. To test the active learning hypothesis, this study analysed the effects of job demands and job control on general problem-solving strategies. A population-based sample of 4,636 individuals (55% women, 45% men) with the same job characteristics measured at two times with a three year time lag was used. Main effects of demands, skill discretion, task authority and control, and the combined effects of demands and control were analysed in logistic regressions, on four outcomes representing general problem-solving strategies. Those reporting high on skill discretion, task authority and control, as well as those reporting high demand/high control and low demand/high control job characteristics were more likely to state using problem solving strategies. Results suggest that working conditions including high levels of control may affect how individuals cope with problems and that workplace characteristics may affect behaviour in the non-work domain.

  18. What would menthol smokers do if menthol in cigarettes were banned? Behavioral intentions and simulated demand.

    Science.gov (United States)

    O'Connor, Richard J; Bansal-Travers, Maansi; Carter, Lawrence P; Cummings, K Michael

    2012-07-01

      The US Food and Drug Administration must consider whether to ban the use of menthol in cigarettes. This study examines how current smokers might respond to such a ban on menthol cigarettes.   Convenience sample of adolescent and adult smokers recruited from an online survey panel.   United States, 2010.   A total of 471 adolescent and adult current cigarette smokers.   Respondents were asked a series of questions about how they might react if menthol cigarettes were banned. In addition, participants completed a simulation purchase task to estimate the demand for menthol and non-menthol cigarettes across a range of prices.   Overall, 36.1% of respondents said they always (18.9%) or usually (17.2%) smoked menthol cigarettes. When asked how they might respond to a ban on menthol cigarettes, 35% of current menthol smokers said they would stop smoking, and 25% said they would 'find a way to buy a menthol brand'. Those who reported they might quit tended to have greater current intentions to quit [odds ratio (OR) = 4.47], while those who reported that they might seek illicit menthol cigarettes were far less likely to report current intentions to quit (OR = 0.06). Estimates for demand elasticity for preferred cigarette type were similar for menthol (α = 0.0051) and non-menthol (α = 0.0049) smokers. Demand elasticity and peak consumption were related to usual cigarette type and cigarettes smoked per day, but did not appear to differ by race, gender or age.   Preliminary evidence suggests that a significant minority of smokers of menthol cigarettes in the United States would try to stop smoking altogether if such cigarettes were banned. © 2012 The Authors, Addiction © 2012 Society for the Study of Addiction.

  19. An Integrated Model of Cognitive Control in Task Switching

    Science.gov (United States)

    Altmann, Erik M.; Gray, Wayne D.

    2008-01-01

    A model of cognitive control in task switching is developed in which controlled performance depends on the system maintaining access to a code in episodic memory representing the most recently cued task. The main constraint on access to the current task code is proactive interference from old task codes. This interference and the mechanisms that…

  20. Operation compatibility: a neglected contribution to dual-task costs

    NARCIS (Netherlands)

    Pannebakker, M.M.; Band, G.P.H.; Ridderinkhof, K.R.

    2009-01-01

    Traditionally, dual-task interference has been attributed to the consequences of task load exceeding capacity limitations. However, the current study demonstrates that in addition to task load, the mutual compatibility of the concurrent processes modulates whether 2 tasks can be performed in

  1. Job Demands and Job Resources in Human Service Managerial Work An External Assessment ThroughWork Content Analysis

    Directory of Open Access Journals (Sweden)

    Linda Corin

    2016-12-01

    Full Text Available Managers’ psychosocial working conditions are important for managerial sustainability in the public sector. The job demands-resources (JD-R model is a widely applied and well-recognized framework for measuring psychosocial working conditions. However, there is still a need for methodological contributions including more objective as well as qualitative ways to assess these conditions. In this study, job demands and job resources as well as the balance between them was qualitatively and externally assessed for first-line human service managers using a work content analysis method. Conditions and actions were focused upon with an external perspective. Special attention was paid to concrete examples and consequences of work characteristics with predefined criteria and cut-off points to guide the assessments. The results reveal an imbalance for human service managers between high levels of job demands and the lack of job resources available to meet these demands. Work overload, conflicting and unclear goals and tasks, emotional demands, restricted control, and lack of supervisory and organizational support generally characterized the managerial assignment. The analysis provided concrete explanations of the current work strain in this group of employees, thereby giving both short-term and long-term possibilities for improvement of managerial work and sustainability.

  2. Oral methylphenidate normalizes cingulate activity in cocaine addiction during a salient cognitive task

    International Nuclear Information System (INIS)

    Goldstein, R.Z.; Woicik, P.A.; Maloney, T.; Tomasi, D.; Alia-Klein, N.; Shan, J.; Honorario, J.; Samaras, D.; Wang, R.; Telang, F.; Wang, G.-J.; Volkow, N.D.

    2010-01-01

    Anterior cingulate cortex (ACC) hypoactivations during cognitive demand are a hallmark deficit in drug addiction. Methylphenidate (MPH) normalizes cortical function, enhancing task salience and improving associated cognitive abilities, in other frontal lobe pathologies; however, in clinical trials, MPH did not improve treatment outcome in cocaine addiction. We hypothesized that oral MPH will attenuate ACC hypoactivations and improve associated performance during a salient cognitive task in individuals with cocaine-use disorders (CUD). In the current functional MRI study, we used a rewarded drug cue-reactivity task previously shown to be associated with hypoactivations in both major ACC subdivisions (implicated in default brain function) in CUD compared with healthy controls. The task was performed by 13 CUD and 14 matched healthy controls on 2 d: after ingesting a single dose of oral MPH (20 mg) or placebo (lactose) in a counterbalanced fashion. Results show that oral MPH increased responses to this salient cognitive task in both major ACC subdivisions (including the caudal-dorsal ACC and rostroventromedial ACC extending to the medial orbitofrontal cortex) in the CUD. These functional MRI results were associated with reduced errors of commission (a common impulsivity measure) and improved task accuracy, especially during the drug (vs. neutral) cue-reactivity condition in all subjects. The clinical application of such MPH-induced brain-behavior enhancements remains to be tested.

  3. Barriers to critical thinking: workflow interruptions and task switching among nurses.

    Science.gov (United States)

    Cornell, Paul; Riordan, Monica; Townsend-Gervis, Mary; Mobley, Robin

    2011-10-01

    Nurses are increasingly called upon to engage in critical thinking. However, current workflow inhibits this goal with frequent task switching and unpredictable demands. To assess workflow's cognitive impact, nurses were observed at 2 hospitals with different patient loads and acuity levels. Workflow on a medical/surgical and pediatric oncology unit was observed, recording tasks, tools, collaborators, and locations. Nineteen nurses were observed for a total of 85.2 hours. Tasks were short with a mean duration of 62.4 and 81.6 seconds on the 2 units. More than 50% of the recorded tasks were less than 30 seconds in length. An analysis of task sequence revealed few patterns and little pairwise repetition. Performance on specific tasks differed between the 2 units, but the character of the workflow was highly similar. The nonrepetitive flow and high amount of switching indicate nurses experience a heavy cognitive load with little uninterrupted time. This implies that nurses rarely have the conditions necessary for critical thinking.

  4. Effects of Task Instruction on Autobiographical Memory Specificity in Young and Older Adults

    Science.gov (United States)

    Ford, Jaclyn Hennessey; Rubin, David C.; Giovanello, Kelly S.

    2013-01-01

    Older adults tend to retrieve autobiographical information that is overly general (i.e. not restricted to a single event, termed the overgenerality effect) relative to young adults’ specific memories. A vast majority of studies that have reported overgenerality effects explicitly instruct participants to retrieve specific memories, thereby requiring participants to maintain task goals, inhibit inappropriate responses, and control their memory search. Since these processes are impaired in healthy aging, it is important to determine whether such task instructions influence the magnitude of the overgenerality effect in older adults. In the current study, participants retrieved autobiographical memories during presentation of musical clips. Task instructions were manipulated to separate age-related differences in the specificity of underlying memory representations from age-related differences in following task instructions. Whereas young adults modulated memory specificity based on task demands, older adults did not. These findings suggest that reported rates of overgenerality in older adults’ memories may include age-related differences in memory representation, as well as differences in task compliance. Such findings provide a better understanding of the underlying cognitive mechanisms involved in age-related changes in autobiographical memory and may also be valuable for future research examining effects of overgeneral memory on general well-being. PMID:23915176

  5. Effects of task instruction on autobiographical memory specificity in young and older adults.

    Science.gov (United States)

    Ford, Jaclyn Hennessey; Rubin, David C; Giovanello, Kelly S

    2014-01-01

    Older adults tend to retrieve autobiographical information that is overly general (i.e., not restricted to a single event, termed the overgenerality effect) relative to young adults' specific memories. A vast majority of studies that have reported overgenerality effects explicitly instruct participants to retrieve specific memories, thereby requiring participants to maintain task goals, inhibit inappropriate responses, and control their memory search. Since these processes are impaired in healthy ageing, it is important to determine whether such task instructions influence the magnitude of the overgenerality effect in older adults. In the current study participants retrieved autobiographical memories during presentation of musical clips. Task instructions were manipulated to separate age-related differences in the specificity of underlying memory representations from age-related differences in following task instructions. Whereas young adults modulated memory specificity based on task demands, older adults did not. These findings suggest that reported rates of overgenerality in older adults' memories might include age-related differences in memory representation, as well as differences in task compliance. Such findings provide a better understanding of the underlying cognitive mechanisms involved in age-related changes in autobiographical memory and may also be valuable for future research examining effects of overgeneral memory on general well-being.

  6. Oral methylphenidate normalizes cingulate activity in cocaine addiction during a salient cognitive task

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, R.Z.; Goldstein, R.Z.; Woicik, P.A.; Maloney, T.; Tomasi, D.; Alia-Klein, N.; Shan, J.; Honorario, J.; Samaras, d.; Wang, R.; Telang, F.; Wang, G.-J.; Volkow, N.D.

    2010-09-21

    Anterior cingulate cortex (ACC) hypoactivations during cognitive demand are a hallmark deficit in drug addiction. Methylphenidate (MPH) normalizes cortical function, enhancing task salience and improving associated cognitive abilities, in other frontal lobe pathologies; however, in clinical trials, MPH did not improve treatment outcome in cocaine addiction. We hypothesized that oral MPH will attenuate ACC hypoactivations and improve associated performance during a salient cognitive task in individuals with cocaine-use disorders (CUD). In the current functional MRI study, we used a rewarded drug cue-reactivity task previously shown to be associated with hypoactivations in both major ACC subdivisions (implicated in default brain function) in CUD compared with healthy controls. The task was performed by 13 CUD and 14 matched healthy controls on 2 d: after ingesting a single dose of oral MPH (20 mg) or placebo (lactose) in a counterbalanced fashion. Results show that oral MPH increased responses to this salient cognitive task in both major ACC subdivisions (including the caudal-dorsal ACC and rostroventromedial ACC extending to the medial orbitofrontal cortex) in the CUD. These functional MRI results were associated with reduced errors of commission (a common impulsivity measure) and improved task accuracy, especially during the drug (vs. neutral) cue-reactivity condition in all subjects. The clinical application of such MPH-induced brain-behavior enhancements remains to be tested.

  7. Multi-modal demands of a smartphone used to place calls and enter addresses during highway driving relative to two embedded systems

    Science.gov (United States)

    Reimer, Bryan; Mehler, Bruce; Reagan, Ian; Kidd, David; Dobres, Jonathan

    2016-01-01

    Abstract There is limited research on trade-offs in demand between manual and voice interfaces of embedded and portable technologies. Mehler et al. identified differences in driving performance, visual engagement and workload between two contrasting embedded vehicle system designs (Chevrolet MyLink and Volvo Sensus). The current study extends this work by comparing these embedded systems with a smartphone (Samsung Galaxy S4). None of the voice interfaces eliminated visual demand. Relative to placing calls manually, both embedded voice interfaces resulted in less eyes-off-road time than the smartphone. Errors were most frequent when calling contacts using the smartphone. The smartphone and MyLink allowed addresses to be entered using compound voice commands resulting in shorter eyes-off-road time compared with the menu-based Sensus but with many more errors. Driving performance and physiological measures indicated increased demand when performing secondary tasks relative to ‘just driving’, but were not significantly different between the smartphone and embedded systems. Practitioner Summary: The findings show that embedded system and portable device voice interfaces place fewer visual demands on the driver than manual interfaces, but they also underscore how differences in system designs can significantly affect not only the demands placed on drivers, but also the successful completion of tasks. PMID:27110964

  8. Multi-modal demands of a smartphone used to place calls and enter addresses during highway driving relative to two embedded systems.

    Science.gov (United States)

    Reimer, Bryan; Mehler, Bruce; Reagan, Ian; Kidd, David; Dobres, Jonathan

    2016-12-01

    There is limited research on trade-offs in demand between manual and voice interfaces of embedded and portable technologies. Mehler et al. identified differences in driving performance, visual engagement and workload between two contrasting embedded vehicle system designs (Chevrolet MyLink and Volvo Sensus). The current study extends this work by comparing these embedded systems with a smartphone (Samsung Galaxy S4). None of the voice interfaces eliminated visual demand. Relative to placing calls manually, both embedded voice interfaces resulted in less eyes-off-road time than the smartphone. Errors were most frequent when calling contacts using the smartphone. The smartphone and MyLink allowed addresses to be entered using compound voice commands resulting in shorter eyes-off-road time compared with the menu-based Sensus but with many more errors. Driving performance and physiological measures indicated increased demand when performing secondary tasks relative to 'just driving', but were not significantly different between the smartphone and embedded systems. Practitioner Summary: The findings show that embedded system and portable device voice interfaces place fewer visual demands on the driver than manual interfaces, but they also underscore how differences in system designs can significantly affect not only the demands placed on drivers, but also the successful completion of tasks.

  9. Differential effects of white noise in cognitive and perceptual tasks

    Directory of Open Access Journals (Sweden)

    Nora Alicia Herweg

    2015-11-01

    Full Text Available Beneficial effects of noise on higher cognition have recently attracted attention. Hypothesizing an involvement of the mesolimbic dopamine system and its functional interactions with cortical areas, the current study aimed to demonstrate a facilitation of dopamine-dependent attentional and mnemonic functions by externally applying white noise in five behavioral experiments including a total sample of 167 healthy human subjects. During working memory, acoustic white noise impaired accuracy when presented during the maintenance period (experiment 1-3. In a reward based long-term memory task, white noise accelerated perceptual judgments for scene images during encoding but left subsequent recognition memory unaffected (experiment 4. In a modified Posner task (experiment 5, the benefit due to white noise in attentional orienting correlated weakly with reward dependence, a personality trait that has been associated with the dopaminergic system. These results suggest that white noise has no general effect on cognitive functions. Instead, they indicate differential effects on perception and cognition depending on a variety of factors such as task demands and timing of white noise presentation.

  10. Differential effects of white noise in cognitive and perceptual tasks.

    Science.gov (United States)

    Herweg, Nora A; Bunzeck, Nico

    2015-01-01

    Beneficial effects of noise on higher cognition have recently attracted attention. Hypothesizing an involvement of the mesolimbic dopamine system and its functional interactions with cortical areas, the current study aimed to demonstrate a facilitation of dopamine-dependent attentional and mnemonic functions by externally applying white noise in five behavioral experiments including a total sample of 167 healthy human subjects. During working memory, acoustic white noise impaired accuracy when presented during the maintenance period (Experiments 1-3). In a reward based long-term memory task, white noise accelerated perceptual judgments for scene images during encoding but left subsequent recognition memory unaffected (Experiment 4). In a modified Posner task (Experiment 5), the benefit due to white noise in attentional orienting correlated weakly with reward dependence, a personality trait that has been associated with the dopaminergic system. These results suggest that white noise has no general effect on cognitive functions. Instead, they indicate differential effects on perception and cognition depending on a variety of factors such as task demands and timing of white noise presentation.

  11. Task-Based Variability in Children's Singing Accuracy

    Science.gov (United States)

    Nichols, Bryan E.

    2016-01-01

    The purpose of this study was to explore the effect of task demands on children's singing accuracy. A 2 × 4 factorial design was used to examine the performance of fourth-grade children (N = 120) in solo and doubled response conditions. Each child sang four task types: single pitch, interval, pattern, and the song "Jingle Bells." The…

  12. Job Management and Task Bundling

    Science.gov (United States)

    Berkowitz, Evan; Jansen, Gustav R.; McElvain, Kenneth; Walker-Loud, André

    2018-03-01

    High Performance Computing is often performed on scarce and shared computing resources. To ensure computers are used to their full capacity, administrators often incentivize large workloads that are not possible on smaller systems. Measurements in Lattice QCD frequently do not scale to machine-size workloads. By bundling tasks together we can create large jobs suitable for gigantic partitions. We discuss METAQ and mpi_jm, software developed to dynamically group computational tasks together, that can intelligently backfill to consume idle time without substantial changes to users' current workflows or executables.

  13. Job Management and Task Bundling

    Directory of Open Access Journals (Sweden)

    Berkowitz Evan

    2018-01-01

    Full Text Available High Performance Computing is often performed on scarce and shared computing resources. To ensure computers are used to their full capacity, administrators often incentivize large workloads that are not possible on smaller systems. Measurements in Lattice QCD frequently do not scale to machine-size workloads. By bundling tasks together we can create large jobs suitable for gigantic partitions. We discuss METAQ and mpi_jm, software developed to dynamically group computational tasks together, that can intelligently backfill to consume idle time without substantial changes to users’ current workflows or executables.

  14. An assessment of the influence of demand response on demand elasticity in electricity retail market

    NARCIS (Netherlands)

    Fonteijn, R.; Babar, M.; Kamphuis, I.G.

    2015-01-01

    A transition towards a sustainable society is currently ongoing. In the electrical power system, this is reflected by the increasing share of renewable energy sources (RES). The weather dependence of some RES results in intermittent and volatile behaviour, thus matching supply and demand has become

  15. Harnessing the power of demand

    Energy Technology Data Exchange (ETDEWEB)

    Sheffrin, Anjali; Yoshimura, Henry; LaPlante, David; Neenan, Bernard

    2008-03-15

    Demand response can provide a series of economic services to the market and also provide ''insurance value'' under low-likelihood, but high-impact circumstances in which grid reliablity is enhanced. Here is how ISOs and RTOs are fostering demand response within wholesale electricity markets. (author)

  16. Guidelines for forecasting energy demand

    International Nuclear Information System (INIS)

    Sonino, T.

    1976-11-01

    Four methodologies for forecasting energy demand are reviewed here after considering the role of energy in the economy and the analysis of energy use in different economic sectors. The special case of Israel is considered throughout, and some forecasts for energy demands in the year 2000 are presented. An energy supply mix that may be considered feasible is proposed. (author)

  17. Coal background paper. Coal demand

    International Nuclear Information System (INIS)

    1997-01-01

    Statistical data are presented on coal demands in IEA and OECD member countries and in other countries. Coal coaking and coaking coal consumption data are tabulated, and IEA secretariat's coal demand projections are summarized. Coal supply and production data by countries are given. Finally, coal trade data are presented, broken down for hard coal, steam coal, coking coal (imports and export). (R.P.)

  18. Uranium resources, demand and production

    International Nuclear Information System (INIS)

    Stipanicic, P.N.

    1985-05-01

    Estimations of the demand and production of principal uranium resource categories are presented. The estimations based on data analysis made by a joint 'NEA/IAEA Working Party on Uranium Resources' and the corresponding results are published by the OECD (Organization for Economic Co-operation and Development) in the 'Uranium Resources, Production and Demand' Known as 'Red Book'. (M.C.K.) [pt

  19. Demand differentiation in inventory systems

    NARCIS (Netherlands)

    Kleijn, M.J.

    1998-01-01

    This book deals with inventory systems where customer demand is categorised into different classes. Most inventory systems do not take into account individual customer preferences for a given product, and therefore handle all demand in a similar way. Nowadays, market segmentation has become a

  20. Demand Response in Smart Grids

    DEFF Research Database (Denmark)

    Hansen, Jacob; Knudsen, Jesper Viese; Annaswamy, Anuradha M.

    2014-01-01

    In recent decades, moves toward higher integration of Renewable Energy Resources have called for fundamental changes in both the planning and operation of the overall power grid. One such change is the incorporation of Demand Response (DR), the process by which consumers can adjust their demand...

  1. Credit demand in Mozambican manufacturing

    DEFF Research Database (Denmark)

    Byiers, Bruce; Rand, John; Tarp, Finn

    2010-01-01

    This paper uses two industrial firm surveys to identify the key determinants of credit demand in Mozambican manufacturing. We construct five different measures of being credit constrained and estimate desired debt demand. Besides firm size and ownership structure, we find evidence that general...

  2. Job demands-resources model

    NARCIS (Netherlands)

    A.B. Bakker (Arnold); E. Demerouti (Eva)

    2013-01-01

    markdownabstract* The question of what causes job stress and what motivates people has received a lot of research attention during the past five decades. In this paper, we discuss Job Demands-Resources (JD-R) theory, which represents an extension of the Job Demands-Resources model (Bakker &

  3. Residential energy demand in Brazil

    International Nuclear Information System (INIS)

    Arouca, M.; Gomes, F.M.; Rosa, L.P.

    1981-01-01

    The energy demand in Brazilian residential sector is studied, discussing the methodology for analyzing this demand from some ideas suggested, for developing an adequate method to brazilian characteristics. The residential energy consumption of several fuels in Brazil is also presented, including a comparative evaluation with the United States and France. (author)

  4. Demand as Frequency Controlled Reserve

    DEFF Research Database (Denmark)

    Xu, Zhao; Togeby, Mikael; Østergaard, Jacob

    This report summaries the research outcomes of the project ‘Demand as Frequency Controlled Reserve (DFR)’, which has received the support from Energinet.dk’s PSO program, Grant no. 2005-2-6380. The objective of this project is to investigate the technology of using electricity demands for providing...

  5. Supply and Demand for Business Education in Naval Aviation

    National Research Council Canada - National Science Library

    Gray, Obra L

    2005-01-01

    ... modernization with current readiness. This project analyzes the supply and demand for postgraduate business education to determine how prepared Naval Aviation is to achieve long-term transformation objectives...

  6. SMALL SERIAL AND SERIAL PRODUCTION MANAGEMENT IN UNSTABLE DEMAND ENVIROUMENT

    Directory of Open Access Journals (Sweden)

    Tsomaeva I. V.

    2014-03-01

    Full Text Available The work presents the methodological approach to production program of the enterprise serial engineering for the current period in the conditions of uncertainty of demand. Here are two problems with this. The first is connected with the formation of the production program of the next quarter, year. Objective could be to stochastic programming, but this task is difficult. Therefore, in this paper we proposed a simple solution. On the basis of statistical historical information about the deviation of actual sales data products from predicted by Monte Carlo generated a lot of production programs. Fixed worst key performance (sales, profit etc. The difference between the values of the planned target and the settlement defines stochastic reserve, to be established at the expense of additional innovations. The second problem is connected with the formation of the production program production in the planned month, taking into account the creation of stocks of production in the conditions when for a short period of time is difficult to build a pattern of change in the quantity demanded by month for serial production, as in some months of the year the products are not produced nor sold. To justify the level of inventories of finished products is information on deviations from the fact plan for past periods. Built function of frequency distribution of the values of deviations. This allows you to further build the methodology for determining the level of production (taking into account the reserves and sales of products that deliver maximum economic effect from the sales in the conditions of a random process of realization of production.

  7. Costs of task allocation with local feedback: Effects of colony size and extra workers in social insects and other multi-agent systems.

    Science.gov (United States)

    Radeva, Tsvetomira; Dornhaus, Anna; Lynch, Nancy; Nagpal, Radhika; Su, Hsin-Hao

    2017-12-01

    Adaptive collective systems are common in biology and beyond. Typically, such systems require a task allocation algorithm: a mechanism or rule-set by which individuals select particular roles. Here we study the performance of such task allocation mechanisms measured in terms of the time for individuals to allocate to tasks. We ask: (1) Is task allocation fundamentally difficult, and thus costly? (2) Does the performance of task allocation mechanisms depend on the number of individuals? And (3) what other parameters may affect their efficiency? We use techniques from distributed computing theory to develop a model of a social insect colony, where workers have to be allocated to a set of tasks; however, our model is generalizable to other systems. We show, first, that the ability of workers to quickly assess demand for work in tasks they are not currently engaged in crucially affects whether task allocation is quickly achieved or not. This indicates that in social insect tasks such as thermoregulation, where temperature may provide a global and near instantaneous stimulus to measure the need for cooling, for example, it should be easy to match the number of workers to the need for work. In other tasks, such as nest repair, it may be impossible for workers not directly at the work site to know that this task needs more workers. We argue that this affects whether task allocation mechanisms are under strong selection. Second, we show that colony size does not affect task allocation performance under our assumptions. This implies that when effects of colony size are found, they are not inherent in the process of task allocation itself, but due to processes not modeled here, such as higher variation in task demand for smaller colonies, benefits of specialized workers, or constant overhead costs. Third, we show that the ratio of the number of available workers to the workload crucially affects performance. Thus, workers in excess of those needed to complete all tasks

  8. Costs of task allocation with local feedback: Effects of colony size and extra workers in social insects and other multi-agent systems.

    Directory of Open Access Journals (Sweden)

    Tsvetomira Radeva

    2017-12-01

    Full Text Available Adaptive collective systems are common in biology and beyond. Typically, such systems require a task allocation algorithm: a mechanism or rule-set by which individuals select particular roles. Here we study the performance of such task allocation mechanisms measured in terms of the time for individuals to allocate to tasks. We ask: (1 Is task allocation fundamentally difficult, and thus costly? (2 Does the performance of task allocation mechanisms depend on the number of individuals? And (3 what other parameters may affect their efficiency? We use techniques from distributed computing theory to develop a model of a social insect colony, where workers have to be allocated to a set of tasks; however, our model is generalizable to other systems. We show, first, that the ability of workers to quickly assess demand for work in tasks they are not currently engaged in crucially affects whether task allocation is quickly achieved or not. This indicates that in social insect tasks such as thermoregulation, where temperature may provide a global and near instantaneous stimulus to measure the need for cooling, for example, it should be easy to match the number of workers to the need for work. In other tasks, such as nest repair, it may be impossible for workers not directly at the work site to know that this task needs more workers. We argue that this affects whether task allocation mechanisms are under strong selection. Second, we show that colony size does not affect task allocation performance under our assumptions. This implies that when effects of colony size are found, they are not inherent in the process of task allocation itself, but due to processes not modeled here, such as higher variation in task demand for smaller colonies, benefits of specialized workers, or constant overhead costs. Third, we show that the ratio of the number of available workers to the workload crucially affects performance. Thus, workers in excess of those needed to

  9. A cognitive task analysis of the SGTR scenario

    International Nuclear Information System (INIS)

    Hollnagel, E.; Edland, A.; Svenson, O.

    1996-04-01

    This report constitutes a contribution to the NKS/RAK-1:3 project on Integrated Sequence Analysis. Following the meeting at Ringhals, the work was proposed to be performed by the following three steps: Task 1. Cognitive Task Analysis of the E-3 procedure. Task 2. Evaluation and revision of task analysis with Ringhals/KSU experts. Task 3. Integration with simulator data. The Cognitive Task Analysis (CTA) of Task 1 uses the Goals-Means Task Analysis (GMTA) method to identify the sequence of tasks and task steps necessary to achieve the goals of the procedure. It is based on material supplied by Ringhals, which describes the E-3 procedure, including the relevant ES and ECA procedures. The analysis further outlines the cognitive demands profile associated with individual task steps as well as with the task as a whole, as an indication of the nominal task load. The outcome of the cognitive task analysis provides a basis for proposing an adequate event tree. This report describes the results from Task 1. The work has included a two-day meeting between the three contributors, as well as the exchange of intermediate results and comments throughout the period. After the initial draft of the report was prepared, an opportunity was given to observe the SGTR scenario in a full-scope training simulator, and to discuss the details with the instructors. This led to several improvements from the initial draft. (EG)

  10. Musical expertise has minimal impact on dual task performance.

    Science.gov (United States)

    Cocchini, Gianna; Filardi, Maria Serena; Crhonkova, Marcela; Halpern, Andrea R

    2017-05-01

    Studies investigating effect of practice on dual task performance have yielded conflicting findings, thus supporting different theoretical accounts about the organisation of attentional resources when tasks are performed simultaneously. Because practice has been proven to reduce the demand of attention for the trained task, the impact of long-lasting training on one task is an ideal way to better understand the mechanisms underlying dual task decline in performance. Our study compared performance during dual task execution in expert musicians compared to controls with little if any musical experience. Participants performed a music recognition task and a visuo-spatial task separately (single task) or simultaneously (dual task). Both groups showed a significant but similar performance decline during dual tasks. In addition, the two groups showed a similar decline of dual task performance during encoding and retrieval of the musical information, mainly attributed to a decline in sensitivity. Our results suggest that attention during dual tasks is similarly distributed by expert and non-experts. These findings are in line with previous studies showing a lack of sensitivity to difficulty and lack of practice effect during dual tasks, supporting the idea that different tasks may rely on different and not-sharable attentional resources.

  11. China expands refining sector to handle booming oil demand

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    China's refining sector is in the midst of a major expansion and reorganization in response to booming domestic demand for petroleum products. Plans call for hiking crude processing capacity to 3.9 million b/d in 1995 from the current 3.085 million b/d. Much of that 26% increase will come where the products demand growth is the strongest: China's coastal provinces, notably those in the southeast. Despite the demand surge, China's refineries operated at only 74% of capacity in 1991, and projections for 1992 weren't much better. Domestic crude supply is limited because of Beijing's insistence on maintaining crude export levels, a major source of hard currency foreign exchange. The paper discusses the superheated demand; exports and imports; the refining infrastructure; the Shenzhen refinery; Hong Kong demand; southeast coast demand; 1993 plans; and foreign investment

  12. Does Knowledge Contribute to the Acceptance of Demand Response?

    Directory of Open Access Journals (Sweden)

    Salla Annala

    2014-03-01

    Full Text Available More flexible demand side would benefit the electricity markets, networks and sustainable power generation in many ways. The success of demand response programs, however, relies on consumer acceptance. This paper reviews previous studies about acceptability of different kinds of residential demand response programs. Furthermore, it discusses whether consumers who are more aware of the principles and benefits of demand response have more positive attitudes towards demand response programs. The results of the literature review and two survey studies suggest that price and security of supply are currently bigger motives to change consumption behaviour than environmental issues and that the savings expected to trigger any action (and to lead to lasting change in behaviour may be relatively high. Therefore, the framing of demand response programs goals may affect the acceptance. Additionally, consumers seem to prefer simple price structures that remain constant for a long time to more dynamic options.

  13. The effect of task complexity and task conditions on foreign language development and performance: three empirical studies

    NARCIS (Netherlands)

    Sercu, L.; de Wachter, L.; Peters, E.; Kuiken, F.; Vedder, I.

    2006-01-01

    It has been argued that tasks constitute a valid alternative unit to sequence the language learning process, as opposed to linguistically defined syllabuses. Implementing this claim presupposes that it is possible to access the cognitive and linguistic demands of tasks, so that they can be sequenced

  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. Are demand forecasting techniques applicable to libraries?

    OpenAIRE

    Sridhar, M. S.

    1984-01-01

    Examines the nature and limitations of demand forecasting, discuses plausible methods of forecasting demand for information, suggests some useful hints for demand forecasting and concludes by emphasizing unified approach to demand forecasting.

  16. A Heuristic Task Scheduling Algorithm for Heterogeneous Virtual Clusters

    OpenAIRE

    Weiwei Lin; Wentai Wu; James Z. Wang

    2016-01-01

    Cloud computing provides on-demand computing and storage services with high performance and high scalability. However, the rising energy consumption of cloud data centers has become a prominent problem. In this paper, we first introduce an energy-aware framework for task scheduling in virtual clusters. The framework consists of a task resource requirements prediction module, an energy estimate module, and a scheduler with a task buffer. Secondly, based on this framework, we propose a virtual ...

  17. Project Tasks in Robotics

    DEFF Research Database (Denmark)

    Sørensen, Torben; Hansen, Poul Erik

    1998-01-01

    Description of the compulsary project tasks to be carried out as a part of DTU course 72238 Robotics......Description of the compulsary project tasks to be carried out as a part of DTU course 72238 Robotics...

  18. Workplace for analysis of task performance

    NARCIS (Netherlands)

    Bos, J; Mulder, LJM; van Ouwerkerk, RJ; Maarse, FJ; Akkerman, AE; Brand, AN; Mulder, LJM

    2003-01-01

    In current research on mental workload and task performance a large gap exists between laboratory based studies and research projects in real life working practice. Tasks conducted within a laboratory environment often lack a strong resemblance with real life working situations. This paper presents

  19. Electric demand and the antinuclear movement

    International Nuclear Information System (INIS)

    Studness, C.M.

    1984-01-01

    The author feels that, with electric demand growth of 4.5 to 5% per year expected, it will be only a matter of time before stepping-up the stream of utility capacity additions becomes an important issue. If demand grows 4.5% per year instead of 2.8% as projected by NERC, demand will be 10% higher and peak reserve margins about 12 percentage points lower than envisioned by the NERC projections after five years. By 1988 or 1989, little or no excess capacity will remain, and the utilities will be faced with adding twice as much capacity annually as now planned to avoid service deterioration. As questions about the adequacy of current utility capacity plans and concerns about service quality move toward center stage, the antinuclear movement should find it increasingly difficult to garner the broad support it now enjoys. Capacity represented by any uncompleted nuclear plants will appear increasingly beneficial, and those who do not have strong antinuclear sentiments should become increasingly hesitant about lending support to the movement. Accordingly, electric demand growth in due course can be expected to drain marginal supporters from the antinuclear movement and thereby erode the movement's vitality

  20. Task assignment and coaching

    OpenAIRE

    Dominguez-Martinez, S.

    2009-01-01

    An important task of a manager is to motivate her subordinates. One way in which a manager can give incentives to junior employees is through the assignment of tasks. How a manager allocates tasks in an organization, provides information to the junior employees about his ability. Without coaching from a manager, the junior employee only has information about his past performance. Based on his past performance, a talented junior who has performed a difficult task sometimes decides to leave the...

  1. Functional Task Test (FTT)

    Science.gov (United States)

    Bloomberg, Jacob J.; Mulavara, Ajitkumar; Peters, Brian T.; Rescheke, Millard F.; Wood, Scott; Lawrence, Emily; Koffman, Igor; Ploutz-Snyder, Lori; Spiering, Barry A.; Feeback, Daniel L.; hide

    2009-01-01

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

  2. Task assignment and coaching

    NARCIS (Netherlands)

    Dominguez-Martinez, S.

    2009-01-01

    An important task of a manager is to motivate her subordinates. One way in which a manager can give incentives to junior employees is through the assignment of tasks. How a manager allocates tasks in an organization, provides information to the junior employees about his ability. Without coaching

  3. DeMand: A tool for evaluating and comparing device-level demand and supply forecast models

    DEFF Research Database (Denmark)

    Neupane, Bijay; Siksnys, Laurynas; Pedersen, Torben Bach

    2016-01-01

    Fine-grained device-level predictions of both shiftable and non-shiftable energy demand and supply is vital in order to take advantage of Demand Response (DR) for efficient utilization of Renewable Energy Sources. The selection of an effective device-level load forecast model is a challenging task......, mainly due to the diversity of the models and the lack of proper tools and datasets that can be used to validate them. In this paper, we introduce the DeMand system for fine-tuning, analyzing, and validating the device-level forecast models. The system offers several built-in device-level measurement...... datasets, forecast models, features, and errors measures, thus semi-automating most of the steps of the forecast model selection and validation process. This paper presents the architecture and data model of the DeMand system; and provides a use-case example on how one particular forecast model...

  4. Probabilistic Predictions of Traffic Demand for En Route Sectors Based on Individual Flight Data

    Science.gov (United States)

    2010-01-01

    The Traffic Flow Management System (TFMS) predicts the demand for each sector, and traffic managers use these predictions to spot possible congestion and to take measures to prevent it. These predictions of sector demand, however, are currently made ...

  5. Beads task vs. box task: The specificity of the jumping to conclusions bias.

    Science.gov (United States)

    Balzan, Ryan P; Ephraums, Rachel; Delfabbro, Paul; Andreou, Christina

    2017-09-01

    Previous research involving the probabilistic reasoning 'beads task' has consistently demonstrated a jumping-to-conclusions (JTC) bias, where individuals with delusions make decisions based on limited evidence. However, recent studies have suggested that miscomprehension may be confounding the beads task. The current study aimed to test the conventional beads task against a conceptually simpler probabilistic reasoning "box task" METHODS: One hundred non-clinical participants completed both the beads task and the box task, and the Peters et al. Delusions Inventory (PDI) to assess for delusion-proneness. The number of 'draws to decision' was assessed for both tasks. Additionally, the total amount of on-screen evidence was manipulated for the box task, and two new box task measures were assessed (i.e., 'proportion of evidence requested' and 'deviation from optimal solution'). Despite being conceptually similar, the two tasks did not correlate, and participants requested significantly less information on the beads task relative to the box task. High-delusion-prone participants did not demonstrate hastier decisions on either task; in fact, for box task, this group was observed to be significantly more conservative than low-delusion-prone group. Neither task was incentivized; results need replication with a clinical sample. Participants, and particularly those identified as high-delusion-prone, displayed a more conservative style of responding on the novel box task, relative to the beads task. The two tasks, whilst conceptually similar, appear to be tapping different cognitive processes. The implications of these results are discussed in relation to the JTC bias and the theoretical mechanisms thought to underlie it. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Energy in China: Coping with increasing demand

    International Nuclear Information System (INIS)

    Sandklef, Kristina

    2004-11-01

    Sustaining the increasing energy consumption is crucial to future economic growth in China. This report focuses on the current and future situation of energy production and consumption in China and how China is coping with its increasing domestic energy demand. Today, coal is the most important energy resource, followed by oil and hydropower. Most energy resources are located in the inland, whereas the main demand for energy is in the coastal areas, which makes transportation and transmission of energy vital. The industrial sector is the main driver of the energy consumption in China, but the transport sector and the residential sector will increase their share of consumption in China, but the transport sector and the residential sector will increase their share of consumption by 2020. China's energy intensity decreased during the 1990s, but it is still high in a global comparison. China is projected to increase its energy consumption at least two times between 2000 and 2025. The government has an equal focus on energy conservation and to develop the current energy resources. Coal will continue to be the most important fuel, but the demand for oil, hydropower, natural gas and nuclear power will also increase. The main future challenges are transportation of energy resources within China and securing oil supply, both domestic and imports

  7. Gas demand to rise in the Usa

    International Nuclear Information System (INIS)

    Anon.

    2000-01-01

    Could US consumption of natural gas rise by as much as 13 quadrillion Btu (quads) over the next 20 years? A new study conducted for the American Gas Foundation by Washington Policy and Analysis says it's certainly a possibility if appropriate policies are implemented. 'Fueling the Future: Natural Gas and New Technologies for a Cleaner 21. Century', confirms what natural gas industry professionals have long suspected: changes in US energy policy that favor increased use of natural gas could improve air quality, conserve energy and reduce reliance on imported oil from politically unstable countries. Consequently, the study forecasts that the environmental, economic and efficiency advantages of natural gas-combined with advances in gas-related technologies and the introduction of new end-use technologies - could help push. US gas consumption into the 35-quad range over the next two decades. Currently, American gas demand is close to 22 quads a year. The study tracks two scenarios: a 'current projection', which shows gas demand reaching nearly 30 quads by 2020, and an 'accelerated projection', which foresees demand topping 35 quads by then based on the adoption of national policies encouraging greater use of natural gas. (authors)

  8. Prospective memory in young and older adults: the effects of task importance and ongoing task load.

    Science.gov (United States)

    Smith, Rebekah E; Hunt, R Reed

    2014-01-01

    Remembering to perform an action in the future, called prospective memory, often shows age-related differences in favor of young adults when tested in the laboratory. Recently Smith, Horn, and Bayen (2012; Aging, Neuropsychology, and Cognition, 19, 495) embedded a PM task in an ongoing color-matching task and manipulated the difficulty of the ongoing task by varying the number of colors on each trial of the task. Smith et al. found that age-related differences in PM performance (lower PM performance for older adults relative to young adults) persisted even when older adults could perform the ongoing task as well or better than the young adults. The current study investigates a possible explanation for the pattern of results reported by Smith et al. by including a manipulation of task emphasis: for half of the participants the prospective memory task was emphasize, while for the other half the ongoing color-matching task was emphasized. Older adults performed a 4-color version of the ongoing color-matching task, while young adults completed either the 4-color or a more difficult 6-color version of the ongoing task. Older adults failed to perform as well as the young adults on the prospective memory task regardless of task emphasis, even when older adults were performing as well or better than the young adults on the ongoing color-matching task. The current results indicate that the lack of an effect of ongoing task load on prospective memory task performance is not due to a perception that one or the other task is more important than the other.

  9. Ecological Relevance Determines Task Priority in Older Adults' Multitasking.

    Science.gov (United States)

    Doumas, Michail; Krampe, Ralf Th

    2015-05-01

    Multitasking is a challenging aspect of human behavior, especially if the concurrently performed tasks are different in nature. Several studies demonstrated pronounced performance decrements (dual-task costs) in older adults for combinations of cognitive and motor tasks. However, patterns of costs among component tasks differed across studies and reasons for participants' resource allocation strategies remained elusive. We investigated young and older adults' multitasking of a working memory task and two sensorimotor tasks, one with low (finger force control) and one with high ecological relevance (postural control). The tasks were performed in single-, dual-, and triple-task contexts. Working memory accuracy was reduced in dual-task contexts with either sensorimotor task and deteriorated further under triple-task conditions. Postural and force performance deteriorated with age and task difficulty in dual-task contexts. However, in the triple-task context with its maximum resource demands, older adults prioritized postural control over both force control and memory. Our results identify ecological relevance as the key factor in older adults' multitasking. © The Author 2013. 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.

  10. Petroleum demand continues to grow but slowly

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    While it is always entertaining and intellectually stimulating to look at all the marvelous technological alternatives just around the corner for transport, the transport task in Australia continues to grow and so does petroleum consumption. Australia presently consumes more than 750,000 barrels per day of petroleum products. Latest figures are given for petroleum consumption up to the end of August 1998. They indicate that total demand for petrol has continued to grow, but very slowly. Growth in 1997-1998 compared with 1996-1997 was only 0.3%. This trend for very low growth has been continued into July and August, perhaps indicative of a slow down in the economy

  11. Voltage Controlled Dynamic Demand Response

    DEFF Research Database (Denmark)

    Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Mahat, Pukar

    2013-01-01

    Future power system is expected to be characterized by increased penetration of intermittent sources. Random and rapid fluctuations in demands together with intermittency in generation impose new challenges for power balancing in the existing system. Conventional techniques of balancing by large...... central or dispersed generations might not be sufficient for future scenario. One of the effective methods to cope with this scenario is to enable demand response. This paper proposes a dynamic voltage regulation based demand response technique to be applied in low voltage (LV) distribution feeders....... An adaptive dynamic model has been developed to determine composite voltage dependency of an aggregated load on feeder level. Following the demand dispatch or control signal, optimum voltage setting at the LV substation is determined based on the voltage dependency of the load. Furthermore, a new technique...

  12. Energy demand: Facts and trends

    Energy Technology Data Exchange (ETDEWEB)

    Chateau, B; Lapillonne, B

    1982-01-01

    The relationship between economic development and energy demand is investigated in this book. It gives a detailed analysis of the energy demand dynamics in industrialized countries and compares the past evolution of the driving factors behind energy demand by sector and by end-uses for the main OECD countries: residential sector (space heating, water heating, cooking...), tertiary sector, passenger and goods transport by mode, and industry (with particular emphasis on the steel and cement industry). This analysis leads to a more precise understanding of the long-term trends of energy demand; highlighting the influence on these trends of energy prices, especially after the oil price shocks, and of the type of economic development pattern.

  13. Temperature Effect on Energy Demand

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Duk [Korea Energy Economics Institute, Euiwang (Korea)

    1999-03-01

    We provide various estimates of temperature effect for accommodating seasonality in energy demand, particularly natural gas demand. We exploit temperature response and monthly temperature distribution to estimate the temperature effect on natural gas demand. Both local and global smoothed temperature responses are estimated from empirical relationship between hourly temperature and hourly energy consumption data during the sample period (1990 - 1996). Monthly temperature distribution estimates are obtained by kernel density estimation from temperature dispersion within a month. We integrate temperature response and monthly temperature density over all the temperatures in the sample period to estimate temperature effect on energy demand. Then, estimates of temperature effect are compared between global and local smoothing methods. (author). 15 refs., 14 figs., 2 tabs.

  14. Demand Response Spinning Reserve Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Eto, Joseph H.; Nelson-Hoffman, Janine; Torres, Carlos; Hirth,Scott; Yinger, Bob; Kueck, John; Kirby, Brendan; Bernier, Clark; Wright,Roger; Barat, A.; Watson, David S.

    2007-05-01

    The Demand Response Spinning Reserve project is a pioneeringdemonstration of how existing utility load-management assets can providean important electricity system reliability resource known as spinningreserve. Using aggregated demand-side resources to provide spinningreserve will give grid operators at the California Independent SystemOperator (CAISO) and Southern California Edison (SCE) a powerful, newtool to improve system reliability, prevent rolling blackouts, and lowersystem operating costs.

  15. Television Advertising and Soda Demand

    OpenAIRE

    Lopez, Rigoberto A.; Liu, Yizao; Zhu, Chen

    2012-01-01

    This study examines the effects of television advertising on consumer demand for carbonated soft drinks using a random coefficients logit model (BLP) with household and advertising data from seven U.S. cities over a three year period. We find that advertising decreases the price elasticity of demand, indicating that advertising plays predominantly a persuasive, therefore anti-competitive role in this market. Further results show that brand spillover effects are significant and that measuring ...

  16. Balancing supply and demand resources

    International Nuclear Information System (INIS)

    Sinha, J.; Saleeby, R.G.

    1990-01-01

    This article deals with using demand-side management (DSM) resources as an effective means of balancing supply and demand as a part of least-cost planning. The authors present a more sophisticated application of the load forecast adjustment method that reduces the number of DSM programs that need to be evaluated and provides blocks large enough to eliminate resolution problems in production costing models

  17. Attentional demands of cued walking in healthy young and elderly adults

    NARCIS (Netherlands)

    Peper, C.E.; Oorthuizen, J.K.; Roerdink, M.

    2012-01-01

    Acoustic and visual cues are frequently used in gait rehabilitation. Attuning the steps to the cues is attentionally demanding. We examined the attentional demands of walking to two types of cues using a probe reaction time (RT) task. The steps were cued by either metronome beeps or visual stepping

  18. Data Science in Supply Chain Management: Data-Related Influences on Demand Planning

    Science.gov (United States)

    Jin, Yao

    2013-01-01

    Data-driven decisions have become an important aspect of supply chain management. Demand planners are tasked with analyzing volumes of data that are being collected at a torrential pace from myriad sources in order to translate them into actionable business intelligence. In particular, demand volatilities and planning are vital for effective and…

  19. US residential energy demand and energy efficiency: A stochastic demand frontier approach

    International Nuclear Information System (INIS)

    Filippini, Massimo; Hunt, Lester C.

    2012-01-01

    This paper estimates a US frontier residential aggregate energy demand function using panel data for 48 ‘states’ over the period 1995 to 2007 using stochastic frontier analysis (SFA). Utilizing an econometric energy demand model, the (in)efficiency of each state is modeled and it is argued that this represents a measure of the inefficient use of residential energy in each state (i.e. ‘waste energy’). This underlying efficiency for the US is therefore observed for each state as well as the relative efficiency across the states. Moreover, the analysis suggests that energy intensity is not necessarily a good indicator of energy efficiency, whereas by controlling for a range of economic and other factors, the measure of energy efficiency obtained via this approach is. This is a novel approach to model residential energy demand and efficiency and it is arguably particularly relevant given current US energy policy discussions related to energy efficiency.

  20. Satisfying the demand for financial information in public traded companies

    DEFF Research Database (Denmark)

    Holm, Claus

    A public traded company which wishes to comply with IAS standards and stock exchange requirements for full public disclosure of relevant information faces a major communication task. The Investor Relation policy of such a company has to satisfy a demand for financial information which seems...... line focus to the disclosure of cash flow surrogates like EBITA and EBITDA. Overall, the findings suggest a communication strategy intended to satisfy the demand from the professional analysts. However, the shear number of different key figures and financial ratios identified in the study suggest...

  1. Current status of safety analysis report for ANPP

    International Nuclear Information System (INIS)

    Amirjanyan, A.

    1999-01-01

    Current situation concerning Armenian NPP safety analysis report is considered within the frame of accepted safety practice. Licensing procedure is being developed. Technical support group was established in the Armenian Nuclear Regulatory Authority (ANRA). The task of the group is to study modern methods of NPP in depth safety analysis for technical assistance for the ANRA, and perform independent safety assessments. ANRA will be obliged to demand assistance from various foreign organisations for preparation of different parts of the Safety Analysis Report like determination though certain parts can be prepared in Armenia

  2. Assessing the significance of climate and community factors on urban water demand

    OpenAIRE

    Md Mahmudul Haque; Prasanna Egodawatta; Ataur Rahman; Ashantha Goonetilleke

    2015-01-01

    Ensuring adequate water supply to urban areas is a challenging task due to factors such as rapid urban growth, increasing water demand and climate change. In developing a sustainable water supply system, it is important to identify the dominant water demand factors for any given water supply scheme. This paper applies principal components analysis to identify the factors that dominate residential water demand using the Blue Mountains Water Supply System in Australia as a case study. The resul...

  3. Game-based training of flexibility and attention improves task-switch performance: near and far transfer of cognitive training in an EEG study

    OpenAIRE

    Olfers, Kerwin J. F.; Band, Guido P. H.

    2017-01-01

    There is a demand for ways to enhance cognitive flexibility, as it can be a limiting factor for performance in daily life. Video game training has been linked to advantages in cognitive functioning, raising the question if training with video games can promote cognitive flexibility. In the current study, we investigated if game-based computerized cognitive training (GCCT) could enhance cognitive flexibility in a healthy young adult sample (N = 72), as measured by task-switch performance. Thre...

  4. Stochastic model of forecasting spare parts demand

    OpenAIRE

    Ivan S. Milojević; Rade V. Guberinić

    2012-01-01

    If demand is known for the whole planning period (complete information), then this type of demand or a supply system is deterministic. In the simplest cases, the demand per time unit is constant. If demand levels change over time following a precisely determined and pre-known principle, this type of demand is also classified as deterministic. This quality of demand is very rare. In most cases demand is the product of a process, for example TMS maintenance, whose progression cannot be predicte...

  5. Vagal and sympathetic activity in burnouts during a mentally demanding workday

    NARCIS (Netherlands)

    Zanstra, Ydwine J.; Schellekens, Jan M. H.; Schaap, Cas; Kooistra, Libbe

    2006-01-01

    Objective: We study differences in task performance and related sympathetic-vagal reaction patterns between burnouts and controls during a mentally demanding workday. Method: Thirty-nine adults with burnout and 40 healthy controls performed mental tasks during a simulated workday. At pretest, just

  6. Avoiding the Conflict: Metacognitive Awareness Drives the Selection of Low-Demand Contexts

    NARCIS (Netherlands)

    Desender, K.; Buc Calderon, C.; Van Opstal, F.; Van den Bussche, E.

    2017-01-01

    Previous research attempted to explain how humans strategically adapt behavior in order to achieve successful task performance. Recently, it has been suggested that 1 potential strategy is to avoid tasks that are too demanding. Here, we report 3 experiments that investigate the empirically neglected

  7. Estimating cross-price elasticity of e-cigarettes using a simulated demand procedure.

    Science.gov (United States)

    Grace, Randolph C; Kivell, Bronwyn M; Laugesen, Murray

    2015-05-01

    Our goal was to measure the cross-price elasticity of electronic cigarettes (e-cigarettes) and simulated demand for tobacco cigarettes both in the presence and absence of e-cigarette availability. A sample of New Zealand smokers (N = 210) completed a Cigarette Purchase Task to indicate their demand for tobacco at a range of prices. They sampled an e-cigarette and rated it and their own-brand tobacco for favorability, and indicated how many e-cigarettes and regular cigarettes they would purchase at 0.5×, 1×, and 2× the current market price for regular cigarettes, assuming that the price of e-cigarettes remained constant. Cross-price elasticity for e-cigarettes was estimated as 0.16, and was significantly positive, indicating that e-cigarettes were partially substitutable for regular cigarettes. Simulated demand for regular cigarettes at current market prices decreased by 42.8% when e-cigarettes were available, and e-cigarettes were rated 81% as favorably as own-brand tobacco. However when cigarettes cost 2× the current market price, significantly more smokers said they would quit (50.2%) if e-cigarettes were not available than if they were available (30.0%). Results show that e-cigarettes are potentially substitutable for regular cigarettes and their availability will reduce tobacco consumption. However, e-cigarettes may discourage smokers from quitting entirely as cigarette price increases, so policy makers should consider maintaining a constant relative price differential between e-cigarettes and tobacco cigarettes. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Demand Potential for Goat Meat in Southern States: Empirical Evidence from a Multi-State Goat Meat Consumer Survey

    OpenAIRE

    Nelson, Mack C.; Liu, Xuanli

    2005-01-01

    A survey conducted in 11 Southeastern states elicits consumers' demand and preferences for various goat meat products. The data permit examination of goat meat demand of ethnic populations and the diversity among the states surveyed. The study uses five econometric models to examine the current demand, potential demand, and demand related to season and occasions on the goat meat market. Our analysis suggests that there exist a substantial demand for goat meat and the potential increase in the...

  9. Pattern of Demand For Money

    Directory of Open Access Journals (Sweden)

    Ahmad Berlian

    2017-12-01

    Full Text Available In the activity of the modern economy, the availability of money as a means of transaction is very important, because with the money as a means to pay consumers can easily to get the basic material needs are required, the manufacturer can provide the raw materials of labor for production, and distributors can obtain a variety of merchandise to be delivered at the end consumer. The pattern of use of money is influenced by the attitude of the public in the transaction. Researchers assume, that there are differences among communities, either by group differences in income, educational differences, ethnic differences, differences in profession, and perhaps even religious differences embraced. So as to provide information to the monetary authorities, to enrich the theory of demand for money based economic agents in Indonesia, and for the application of the theory of demand for money, the researchers felt the need to study patterns of use of money. Qualitative research, in addition to knowing whether the variables that affect the demand for money as the above theory is still relevant for economic actors in Indonesia at this time, or even are new variables, as well as the motive of money demand. Keywords: Demand for money, Keynes Theory, qualitative method

  10. Anterior medial prefrontal cortex exhibits activation during task preparation but deactivation during task execution.

    Directory of Open Access Journals (Sweden)

    Hideya Koshino

    Full Text Available BACKGROUND: The anterior prefrontal cortex (PFC exhibits activation during some cognitive tasks, including episodic memory, reasoning, attention, multitasking, task sets, decision making, mentalizing, and processing of self-referenced information. However, the medial part of anterior PFC is part of the default mode network (DMN, which shows deactivation during various goal-directed cognitive tasks compared to a resting baseline. One possible factor for this pattern is that activity in the anterior medial PFC (MPFC is affected by dynamic allocation of attentional resources depending on task demands. We investigated this possibility using an event related fMRI with a face working memory task. METHODOLOGY/PRINCIPAL FINDINGS: Sixteen students participated in a single fMRI session. They were asked to form a task set to remember the faces (Face memory condition or to ignore them (No face memory condition, then they were given 6 seconds of preparation period before the onset of the face stimuli. During this 6-second period, four single digits were presented one at a time at the center of the display, and participants were asked to add them and to remember the final answer. When participants formed a task set to remember faces, the anterior MPFC exhibited activation during a task preparation period but deactivation during a task execution period within a single trial. CONCLUSIONS/SIGNIFICANCE: The results suggest that the anterior MPFC plays a role in task set formation but is not involved in execution of the face working memory task. Therefore, when attentional resources are allocated to other brain regions during task execution, the anterior MPFC shows deactivation. The results suggest that activation and deactivation in the anterior MPFC are affected by dynamic allocation of processing resources across different phases of processing.

  11. Phonological similarity effect in complex span task.

    Science.gov (United States)

    Camos, Valérie; Mora, Gérôme; Barrouillet, Pierre

    2013-01-01

    The aim of our study was to test the hypothesis that two systems are involved in verbal working memory; one is specifically dedicated to the maintenance of phonological representations through verbal rehearsal while the other would maintain multimodal representations through attentional refreshing. This theoretical framework predicts that phonologically related phenomena such as the phonological similarity effect (PSE) should occur when the domain-specific system is involved in maintenance, but should disappear when concurrent articulation hinders its use. Impeding maintenance in the domain-general system by a concurrent attentional demand should impair recall performance without affecting PSE. In three experiments, we manipulated the concurrent articulation and the attentional demand induced by the processing component of complex span tasks in which participants had to maintain lists of either similar or dissimilar words. Confirming our predictions, PSE affected recall performance in complex span tasks. Although both the attentional demand and the articulatory requirement of the concurrent task impaired recall, only the induction of an articulatory suppression during maintenance made the PSE disappear. These results suggest a duality in the systems devoted to verbal maintenance in the short term, constraining models of working memory.

  12. Transport Task Force Leadership, Task 4

    International Nuclear Information System (INIS)

    Callen, J.D.

    1991-07-01

    The Transport Task Force (TTF) was initiated as a broad-based US magnetic fusion community activity during the fall of 1988 to focus attention on and encourage development of an increased understanding of anomalous transport in tokamaks. The overall TTF goal is to make progress on Characterizing, Understanding and Identifying how to Reduce plasma transport in tokamaks -- to CUIR transport

  13. "Photographing money" task pricing

    Science.gov (United States)

    Jia, Zhongxiang

    2018-05-01

    "Photographing money" [1]is a self-service model under the mobile Internet. The task pricing is reasonable, related to the success of the commodity inspection. First of all, we analyzed the position of the mission and the membership, and introduced the factor of membership density, considering the influence of the number of members around the mission on the pricing. Multivariate regression of task location and membership density using MATLAB to establish the mathematical model of task pricing. At the same time, we can see from the life experience that membership reputation and the intensity of the task will also affect the pricing, and the data of the task success point is more reliable. Therefore, the successful point of the task is selected, and its reputation, task density, membership density and Multiple regression of task positions, according to which a nhew task pricing program. Finally, an objective evaluation is given of the advantages and disadvantages of the established model and solution method, and the improved method is pointed out.

  14. 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....

  15. Retail Demand Response in Southwest Power Pool

    Energy Technology Data Exchange (ETDEWEB)

    Bharvirkar, Ranjit; Heffner, Grayson; Goldman, Charles

    2009-01-30

    In 2007, the Southwest Power Pool (SPP) formed the Customer Response Task Force (CRTF) to identify barriers to deploying demand response (DR) resources in wholesale markets and develop policies to overcome these barriers. One of the initiatives of this Task Force was to develop more detailed information on existing retail DR programs and dynamic pricing tariffs, program rules, and utility operating practices. This report describes the results of a comprehensive survey conducted by LBNL in support of the Customer Response Task Force and discusses policy implications for integrating legacy retail DR programs and dynamic pricing tariffs into wholesale markets in the SPP region. LBNL conducted a detailed survey of existing DR programs and dynamic pricing tariffs administered by SPP's member utilities. Survey respondents were asked to provide information on advance notice requirements to customers, operational triggers used to call events (e.g. system emergencies, market conditions, local emergencies), use of these DR resources to meet planning reserves requirements, DR resource availability (e.g. seasonal, annual), participant incentive structures, and monitoring and verification (M&V) protocols. Nearly all of the 30 load-serving entities in SPP responded to the survey. Of this group, fourteen SPP member utilities administer 36 DR programs, five dynamic pricing tariffs, and six voluntary customer response initiatives. These existing DR programs and dynamic pricing tariffs have a peak demand reduction potential of 1,552 MW. Other major findings of this study are: o About 81percent of available DR is from interruptible rate tariffs offered to large commercial and industrial customers, while direct load control (DLC) programs account for ~;;14percent. o Arkansas accounts for ~;;50percent of the DR resources in the SPP footprint; these DR resources are primarily managed by cooperatives. o Publicly-owned cooperatives accounted for 54percent of the existing DR resources

  16. Energy supply and demand in California

    Science.gov (United States)

    Griffith, E. D.

    1978-01-01

    The author expresses his views on future energy demand on the west coast of the United States and how that energy demand translates into demand for major fuels. He identifies the major uncertainties in determining what future demands may be. The major supply options that are available to meet projected demands and the policy implications that flow from these options are discussed.

  17. International Oil Supplies and Demands

    Energy Technology Data Exchange (ETDEWEB)

    1991-09-01

    The eleventh Energy Modeling Forum (EMF) working group met four times over the 1989--90 period to compare alternative perspectives on international oil supplies and demands through 2010 and to discuss how alternative supply and demand trends influence the world's dependence upon Middle Eastern oil. Proprietors of eleven economic models of the world oil market used their respective models to simulate a dozen scenarios using standardized assumptions. From its inception, the study was not designed to focus on the short-run impacts of disruptions on oil markets. Nor did the working group attempt to provide a forecast or just a single view of the likely future path for oil prices. The model results guided the group's thinking about many important longer-run market relationships and helped to identify differences of opinion about future oil supplies, demands, and dependence.

  18. Fundamental Travel Demand Model Example

    Science.gov (United States)

    Hanssen, Joel

    2010-01-01

    Instances of transportation models are abundant and detailed "how to" instruction is available in the form of transportation software help documentation. The purpose of this paper is to look at the fundamental inputs required to build a transportation model by developing an example passenger travel demand model. The example model reduces the scale to a manageable size for the purpose of illustrating the data collection and analysis required before the first step of the model begins. This aspect of the model development would not reasonably be discussed in software help documentation (it is assumed the model developer comes prepared). Recommendations are derived from the example passenger travel demand model to suggest future work regarding the data collection and analysis required for a freight travel demand model.

  19. International Oil Supplies and Demands

    International Nuclear Information System (INIS)

    1991-09-01

    The eleventh Energy Modeling Forum (EMF) working group met four times over the 1989--90 period to compare alternative perspectives on international oil supplies and demands through 2010 and to discuss how alternative supply and demand trends influence the world's dependence upon Middle Eastern oil. Proprietors of eleven economic models of the world oil market used their respective models to simulate a dozen scenarios using standardized assumptions. From its inception, the study was not designed to focus on the short-run impacts of disruptions on oil markets. Nor did the working group attempt to provide a forecast or just a single view of the likely future path for oil prices. The model results guided the group's thinking about many important longer-run market relationships and helped to identify differences of opinion about future oil supplies, demands, and dependence

  20. International Oil Supplies and Demands

    International Nuclear Information System (INIS)

    1992-04-01

    The eleventh Energy Modeling Forum (EMF) working group met four times over the 1989--1990 period to compare alternative perspectives on international oil supplies and demands through 2010 and to discuss how alternative supply and demand trends influence the world's dependence upon Middle Eastern oil. Proprietors of eleven economic models of the world oil market used their respective models to simulate a dozen scenarios using standardized assumptions. From its inception, the study was not designed to focus on the short-run impacts of disruptions on oil markets. Nor did the working group attempt to provide a forecast or just a single view of the likely future path for oil prices. The model results guided the group's thinking about many important longer-run market relationships and helped to identify differences of opinion about future oil supplies, demands, and dependence

  1. Consumer demand and quality assurance

    DEFF Research Database (Denmark)

    Grunert, Klaus G; Wognum, Nel; Trienekens, Jacques

    2011-01-01

    Consumers differ in their demands, and this mau have implications for the type of supply chain governance that is most suitable for serving them. We present a segmentation of pork consumers in the EU based on their food-related lifestyles and demand for different pork products. We then present...... an inventory of pork chain governance and quality management systems, also resulting from a pan-European study, and attempt to match types of chains to consumer segments, arguing that the type of quality demanded by the consumers has implications especially for the quality management system governing the chain......, and that these implications are different for fresh meat and processed meat. The paper closes with a call for more collaboration between chain researchers and consumer researchers....

  2. International Oil Supplies and Demands

    Energy Technology Data Exchange (ETDEWEB)

    1992-04-01

    The eleventh Energy Modeling Forum (EMF) working group met four times over the 1989--1990 period to compare alternative perspectives on international oil supplies and demands through 2010 and to discuss how alternative supply and demand trends influence the world's dependence upon Middle Eastern oil. Proprietors of eleven economic models of the world oil market used their respective models to simulate a dozen scenarios using standardized assumptions. From its inception, the study was not designed to focus on the short-run impacts of disruptions on oil markets. Nor did the working group attempt to provide a forecast or just a single view of the likely future path for oil prices. The model results guided the group's thinking about many important longer-run market relationships and helped to identify differences of opinion about future oil supplies, demands, and dependence.

  3. North American supply/demand

    International Nuclear Information System (INIS)

    Pocino, M.C.

    1998-01-01

    The projected supply and demand for natural gas in five major regions of North America for the year 2000 was presented. In most regions, supply is expected to be greater than demand. A summary of how California dealt with an increase in natural gas demand in 1990 was presented. The California strategy included a readjustment of pipeline capacity, storage capacity and transportation. Whereas in the 1980s, when capacity was inadequate, the focus was on competition with alternate fuels, maximized capacity use, primary concern about reliability and only secondary concern about price, in the the 1990s, with excess capacity, the emphasis is on 'gas on gas' competition, efforts to satisfy the customer, primary concern about price, and only marginal concern about reliability. tabs., figs

  4. Climate change and energy demand

    International Nuclear Information System (INIS)

    Hengeveld, H.G.

    1991-01-01

    Climate and weather events affect energy demand in most economic sectors. Linear relationships exist between consumption and heating degree days, and peak electricity demand increases significantly during heat waves. The relative magnitudes of demand changes for a two times carbon dioxide concentration scenario are tabulated, illustrating heating degree days and cooling degree days for 5 Prairie locations. Irrigation, water management, crop seeding and harvesting and weed control are examples of climate-dependent agricultural activities involving significant energy use. The variability of summer season liquid fuel use in the agricultural sector in the Prairie provinces from 1984-1989 shows a relationship between agricultural energy use and regional climate fluctuations. 4 refs., 2 figs., 1 tab

  5. The Effect of Task Type and Pre-task Planning Condition on the Accuracy of Intermediate EFL Learners' Writing Performance

    Directory of Open Access Journals (Sweden)

    Seyeed Mohammad Alavi

    2012-05-01

    Full Text Available Task-based language teaching, which requires learners to transact tasks resembling their real life language needs, demands language learners to perform planning at different stages of their learning. Since various types of tasks can be used in task-based instruction, the present study examined the effect of task types and various participatory structures during pre-task planning on the quality of learners' writing performance, (i.e., accuracy. Towards this end, 120 intermediate EFL students were randomly assigned to 3 experimental groups and one control group. While the experimental groups were subjected to different pre-task planning conditions, (i.e., individual, pair, and group, the control group performed tasks without any planning. During the treatment, they experienced task modeling, presentation and completion. A factorial design was followed in the present study, and the collected data were analyzed through ANOVAs that revealed task type and pre-task planning condition influenced the writing accuracy of the participants in a way that resulted in greater accuracy in the decision-making task in the experimental groups, thereby ensuring the effectiveness of the treatment in mitigating the long-standing problem of EFL learners in achieving higher levels of accuracy when a specific task type is concerned.

  6. Pay for load demand - electricity pricing with load demand component

    International Nuclear Information System (INIS)

    Pyrko, Jurek; Sernhed, Kerstin; Abaravicius, Juozas

    2003-01-01

    This publication is part of a project called Direct and Indirect Load Control in Buildings. Peak load problems have attracted considerable attention in Sweden during last three winters, caused by a significant decrease in available reserve power, which is a consequence of political decisions and liberalisation of the electricity market. A possible way to lower peak loads, avoiding electricity shortages and reducing electricity costs both for users and utilities, is to make customers experience the price difference during peak load periods and, in this way, become more aware of their energy consumption pattern and load demand. As of January 1st 2001, one of the Swedish energy utilities - Sollentuna Energi - operating in the Stockholm area, introduced a new electricity tariff with differentiated grid fees based on a mean value of the peak load every month. This tariff was introduced for all residential customers in the service area. The objective of this study is to investigate the extent to which a Load Demand Component, included in electricity pricing, can influence energy use and load demand in residential buildings. What are the benefits and disadvantages for customers and utilities? This paper investigates the impact of the new tariff on the utility and different types of typical residential customers, making comparisons with previous tariff. Keywords Load demand, electricity pricing, tariff, residential customers, energy behaviour

  7. Load Reduction, Demand Response and Energy Efficient Technologies and Strategies

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, Paul A.; Parker, Graham B.; Hatley, Darrel D.

    2008-11-19

    The Department of Energy’s (DOE’s) Pacific Northwest National Laboratory (PNNL) was tasked by the DOE Office of Electricity (OE) to recommend load reduction and grid integration strategies, and identify additional demand response (energy efficiency/conservation opportunities) and strategies at the Forest City Housing (FCH) redevelopment at Pearl Harbor and the Marine Corps Base Hawaii (MCBH) at Kaneohe Bay. The goal was to provide FCH staff a path forward to manage their electricity load and thus reduce costs at these FCH family housing developments. The initial focus of the work was at the MCBH given the MCBH has a demand-ratchet tariff, relatively high demand (~18 MW) and a commensurate high blended electricity rate (26 cents/kWh). The peak demand for MCBH occurs in July-August. And, on average, family housing at MCBH contributes ~36% to the MCBH total energy consumption. Thus, a significant load reduction in family housing can have a considerable impact on the overall site load. Based on a site visit to the MCBH and meetings with MCBH installation, FCH, and Hawaiian Electric Company (HECO) staff, recommended actions (including a "smart grid" recommendation) that can be undertaken by FCH to manage and reduce peak-demand in family housing are made. Recommendations are also made to reduce overall energy consumption, and thus reduce demand in FCH family housing.

  8. Enabling technologies for industrial energy demand management

    International Nuclear Information System (INIS)

    Dyer, Caroline H.; Hammond, Geoffrey P.; Jones, Craig I.; McKenna, Russell C.

    2008-01-01

    This state-of-science review sets out to provide an indicative assessment of enabling technologies for reducing UK industrial energy demand and carbon emissions to 2050. In the short term, i.e. the period that will rely on current or existing technologies, the road map and priorities are clear. A variety of available technologies will lead to energy demand reduction in industrial processes, boiler operation, compressed air usage, electric motor efficiency, heating and lighting, and ancillary uses such as transport. The prospects for the commercial exploitation of innovative technologies by the middle of the 21st century are more speculative. Emphasis is therefore placed on the range of technology assessment methods that are likely to provide policy makers with a guide to progress in the development of high-temperature processes, improved materials, process integration and intensification, and improved industrial process control and monitoring. Key among the appraisal methods applicable to the energy sector is thermodynamic analysis, making use of energy, exergy and 'exergoeconomic' techniques. Technical and economic barriers will limit the improvement potential to perhaps a 30% cut in industrial energy use, which would make a significant contribution to reducing energy demand and carbon emissions in UK industry. Non-technological drivers for, and barriers to, the take-up of innovative, low-carbon energy technologies for industry are also outlined

  9. Latent factor structure of a behavioral economic marijuana demand curve.

    Science.gov (United States)

    Aston, Elizabeth R; Farris, Samantha G; MacKillop, James; Metrik, Jane

    2017-08-01

    Drug demand, or relative value, can be assessed via analysis of behavioral economic purchase task performance. Five demand indices are typically obtained from drug purchase tasks. The goal of this research was to determine whether metrics of marijuana reinforcement from a marijuana purchase task (MPT) exhibit a latent factor structure that efficiently characterizes marijuana demand. Participants were regular marijuana users (n = 99; 37.4% female, 71.5% marijuana use days [5 days/week], 15.2% cannabis dependent) who completed study assessments, including the MPT, during a baseline session. Principal component analysis was used to examine the latent structure underlying MPT indices. Concurrent validity was assessed via examination of relationships between latent factors and marijuana use, past quit attempts, and marijuana expectancies. A two-factor solution was confirmed as the best fitting structure, accounting for 88.5% of the overall variance. Factor 1 (65.8% variance) reflected "Persistence," indicating sensitivity to escalating marijuana price, which comprised four MPT indices (elasticity, O max , P max , and breakpoint). Factor 2 (22.7% variance) reflected "Amplitude," indicating the amount consumed at unrestricted price (intensity). Persistence factor scores were associated with fewer past marijuana quit attempts and lower expectancies of negative use outcomes. Amplitude factor scores were associated with more frequent use, dependence symptoms, craving severity, and positive marijuana outcome expectancies. Consistent with research on alcohol and cigarette purchase tasks, the MPT can be characterized with a latent two-factor structure. Thus, demand for marijuana appears to encompass distinct dimensions of price sensitivity and volumetric consumption, with differential relations to other aspects of marijuana motivation.

  10. Demand as Frequency Controlled Reserve

    DEFF Research Database (Denmark)

    Xu, Zhao; Østergaard, Jacob; Togeby, Mikael

    2011-01-01

    Relying on generation side alone is deemed insufficient to fulfill the system balancing needs for future Danish power system, where a 50% wind penetration is outlined by the government for year 2025. This paper investigates using the electricity demand as frequency controlled reserve (DFR) as a new...... balancing measure, which has a high potential and can provide many advantages. Firstly, the background of the research is reviewed, including conventional power system reserves and the electricity demand side potentials. Subsequently, the control logics and corresponding design considerations for the DFR...

  11. Prediction Models for Dynamic Demand Response

    Energy Technology Data Exchange (ETDEWEB)

    Aman, Saima; Frincu, Marc; Chelmis, Charalampos; Noor, Muhammad; Simmhan, Yogesh; Prasanna, Viktor K.

    2015-11-02

    As Smart Grids move closer to dynamic curtailment programs, Demand Response (DR) events will become necessary not only on fixed time intervals and weekdays predetermined by static policies, but also during changing decision periods and weekends to react to real-time demand signals. Unique challenges arise in this context vis-a-vis demand prediction and curtailment estimation and the transformation of such tasks into an automated, efficient dynamic demand response (D2R) process. While existing work has concentrated on increasing the accuracy of prediction models for DR, there is a lack of studies for prediction models for D2R, which we address in this paper. Our first contribution is the formal definition of D2R, and the description of its challenges and requirements. Our second contribution is a feasibility analysis of very-short-term prediction of electricity consumption for D2R over a diverse, large-scale dataset that includes both small residential customers and large buildings. Our third, and major contribution is a set of insights into the predictability of electricity consumption in the context of D2R. Specifically, we focus on prediction models that can operate at a very small data granularity (here 15-min intervals), for both weekdays and weekends - all conditions that characterize scenarios for D2R. We find that short-term time series and simple averaging models used by Independent Service Operators and utilities achieve superior prediction accuracy. We also observe that workdays are more predictable than weekends and holiday. Also, smaller customers have large variation in consumption and are less predictable than larger buildings. Key implications of our findings are that better models are required for small customers and for non-workdays, both of which are critical for D2R. Also, prediction models require just few days’ worth of data indicating that small amounts of

  12. Pattern of demand for children in Pakistan.

    Science.gov (United States)

    Ahmed, T

    1992-01-01

    The study aim was to determine the pattern of demand for children and to suggest ways to introduce the idea of a small-family norm and reduce the unmet need for contraception in Pakistan. The concept of demand for children included the wantedness of the last birth and the timing of the next birth and changed with stage in reproductive life cycle. Data were obtained from the Pakistan Contraception Prevalence Survey of 1984/85. Pakistan's strong patriarchal system emphasized rapid achievement of first pregnancy in order to assure the perpetuation of the lineage. Female status, even with advanced education, emphasized fecundity and producing a male heir. The birthing pattern among rural and urban lower-class women is to bear 3-4 children early in marriage. Evidence from prior surveys showed that educated women plan for a delay in second birth. Of the 6655 ever pregnant and nonsterilized women, about 48% of currently married women desired discontinuation of childbearing. 18% desired a delay of childbearing by 2 years and 10% desired no more children after a last undesired pregnancy. Unmet need was estimated at 17% of all women in the sample. Women desiring no more children were primarily older with 6-8 prior births. Indirect fertility estimates were generated by using Arriaga's techniques for stages of family formation. The resulting estimates showed that higher-parity women desiring no more children still had 2 more children, which was evidence of unmet need. Those desiring more children had higher fertility than those not desiring more children. These women also showed different patterns in their total demand for children, ideal family size, currently living children, and desire for their next birth. Ideal size tended to rise over the length of a marriage, which may mean that women with growing families may justify unwanted fertility. Duration of marriage was viewed as a reasonable indicator of need for fertility control and the concomitant need for outreach

  13. Default mode network connectivity during task execution.

    Science.gov (United States)

    Vatansever, D; Menon, D K; Manktelow, A E; Sahakian, B J; Stamatakis, E A

    2015-11-15

    Initially described as task-induced deactivations during goal-directed paradigms of high attentional load, the unresolved functionality of default mode regions has long been assumed to interfere with task performance. However, recent evidence suggests a potential default mode network involvement in fulfilling cognitive demands. We tested this hypothesis in a finger opposition paradigm with task and fixation periods which we compared with an independent resting state scan using functional magnetic resonance imaging and a comprehensive analysis pipeline including activation, functional connectivity, behavioural and graph theoretical assessments. The results indicate task specific changes in the default mode network topography. Behaviourally, we show that increased connectivity of the posterior cingulate cortex with the left superior frontal gyrus predicts faster reaction times. Moreover, interactive and dynamic reconfiguration of the default mode network regions' functional connections illustrates their involvement with the task at hand with higher-level global parallel processing power, yet preserved small-world architecture in comparison with rest. These findings demonstrate that the default mode network does not disengage during this paradigm, but instead may be involved in task relevant processing. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Following the time course of face gender and expression processing: a task-dependent ERP study.

    Science.gov (United States)

    Valdés-Conroy, Berenice; Aguado, Luis; Fernández-Cahill, María; Romero-Ferreiro, Verónica; Diéguez-Risco, Teresa

    2014-05-01

    The effects of task demands and the interaction between gender and expression in face perception were studied using event-related potentials (ERPs). Participants performed three different tasks with male and female faces that were emotionally inexpressive or that showed happy or angry expressions. In two of the tasks (gender and expression categorization) facial properties were task-relevant while in a third task (symbol discrimination) facial information was irrelevant. Effects of expression were observed on the visual P100 component under all task conditions, suggesting the operation of an automatic process that is not influenced by task demands. The earliest interaction between expression and gender was observed later in the face-sensitive N170 component. This component showed differential modulations by specific combinations of gender and expression (e.g., angry male vs. angry female faces). Main effects of expression and task were observed in a later occipito-temporal component peaking around 230 ms post-stimulus onset (EPN or early posterior negativity). Less positive amplitudes in the presence of angry faces and during performance of the gender and expression tasks were observed. Finally, task demands also modulated a positive component peaking around 400 ms (LPC, or late positive complex) that showed enhanced amplitude for the gender task. The pattern of results obtained here adds new evidence about the sequence of operations involved in face processing and the interaction of facial properties (gender and expression) in response to different task demands. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Uranium resources, production and demand in South Africa

    International Nuclear Information System (INIS)

    Brynard, H.J.; Ainslie, L.C.

    1990-01-01

    This paper provides a review of the historical development of the South African uranium market and the current status of uranium exploration, resources and production. A prognosticated view of possible future demand for uranium in South Africa is attempted, taking cognisance of the finite nature of the country's coal resources and estimated world uranium demand. Although well endowed with uranium resources, South Africa could face a shortage of this commodity in the next century, should the predicted electricity growth materials. (author)

  16. Uranium resources, production and demand in South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Brynard, H J; Ainslie, L C [Atomic Energy Corporation of South Africa Ltd., Pretoria (South Africa)

    1990-06-01

    This paper provides a review of the historical development of the South African uranium market and the current status of uranium exploration, resources and production. A prognosticated view of possible future demand for uranium in South Africa is attempted, taking cognisance of the finite nature of the country's coal resources and estimated world uranium demand. Although well endowed with uranium resources, South Africa could face a shortage of this commodity in the next century, should the predicted electricity growth materials. (author)

  17. Planning Annuaulised hours when spike in demand exists

    Directory of Open Access Journals (Sweden)

    MR Sureshkumar

    2012-04-01

    Full Text Available Manpower planning using annualised hours is an effective tool where seasonal demand for staff in industry exists. In annualised hours (AH workers are contracted to work for a certain number of hours per year. The workers are associated with relative efficiency for different types of tasks. This paper proposes a Mixed Integer linear Programming (MILP model to solve an annualised working hours planning problem when spike in demand exists. The holiday weeks for the workers are considered as partially individualised. If a worker has been assigned with more than one type of working week in a week, this will be compensated with one or more holiday week. The performance of the model is demonstrated with an example. It can be seen that this type of modelling helps to meet the spikes in demand with less capacity shortage compared with one working week in a week.

  18. Supporting complex search tasks

    DEFF Research Database (Denmark)

    Gäde, Maria; Hall, Mark; Huurdeman, Hugo

    2015-01-01

    , is fragmented at best. The workshop addressed the many open research questions: What are the obvious use cases and applications of complex search? What are essential features of work tasks and search tasks to take into account? And how do these evolve over time? With a multitude of information, varying from...

  19. Task leaders reports

    International Nuclear Information System (INIS)

    Loriaux, E.F.; Jehee, J.N.T.

    1995-01-01

    Report on CRP-OSS Task 4.1.1. ''Survey of existing documentation relevant to this programme's goals'' and report on CRP-OSS Task 4.1.2. ''Survey of existing Operator Support Systems and the experience with them'' are presented. 2 tabs

  20. Collusion and the elasticity of demand

    OpenAIRE

    David Collie

    2004-01-01

    The analysis of collusion in infinitely repeated Cournot oligopoly games has generally assumed that demand is linear, but this note uses constant-elasticity demand functions to investigate how the elasticity of demand affects the sustainability of collusion.